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Case Study: Shadow Robot
Image courtesy of Shadow Robot: The Shadow Dexterous Hand Series
Robotics Solutions--Giving a Helping Hand
Robots are being adopted at a rapid rate within many varied sectors. Industry challenges once thought too big to solve are now a reality with robotics. Early on, one company had a vision and drive too big to fail—Shadow Robot. Pioneers in the industry, they’ve been on the cutting-edge of robotics for over a decade, delivering customized robotics solutions around the world.
Image courtesy of Shadow Robot: The Shadow Dexterous Hand Series
Product: Shadow Dexterous Hand Robot
Among their award-winning robots, is the Shadow Dexterous Hand. It’s a humanoid hand-and-arm system that provides human-level dexterity at a distance, or remotely, which is referred to as teleoperation. The system tracks human user fingertip positions and orientations relative to the palm, and this next generation robot hand system touts unmatched dexterity.
Hailed among top researchers, the teleoperation robot system gets particular attention when the work environment is unsafe, impractical, expensive, or undesirable. Shadow Robot categorizes these environments into six areas that start with the letter “D,” including work that’s Dull, Dirty, Dangerous, Delicate, Distant, or Difficult.
Examples of work that fall into the six “D’s” include: repetitive tasks on assembly lines, mining, cleaning, fine assembly work, remote maintenance, nuclear decommissioning, bomb disposal, or work in areas difficult to access.
Finding the Right Motion Tracking Solution
With a wide variety of potential use cases in mind, and the intention to do good with robots, Shadow Robot set out to find the right tracking solution. Some of the key, next generation features needed to take their product to the next level included real-time tracking, enabling finger pivoting, finger sliding and finger gaiting, and independent side-to-side finger movement. Shadow Robot faced three main challenges when assessing motion tracking technologies for integration:
1. Requirements for high-fidelity tracking with low latency
2. Line-of-sight occlusions
3. Sensor size
Image courtesy of Shadow Robot: The Shadow Dexterous Hand Series
Challenge #1: High-Fidelity Tracking Capability and Low Latency
The human hand is a highly adaptive extremity, and the robot hand needed to truly replicate the quick dexterity of its human hand counterpart. High-fidelity tracking, a high level of precision, and near-zero lag time, (otherwise known as latency) were critical. Most tracking systems are plagued by latency issues, which can limit applications in robotics, VR (virtual reality) and AR (augmented reality).
Challenge #2: Line-of-Sight Occlusions
An object, person, or equipment can easily block the line-of-sight in tracking applications, causing delays in tracking data. For example, with hand and finger tracking, a hand that moves in the wrong angle or gets out of range, runs the risk of motion tracking disruption. Line-of-sight occlusions are a common issue with optical tracking technologies (otherwise known as camera-based tracking). This can pose a challenge for some applications.
Challenge #3: Sensor Size
Finding sensors small enough to fit into a glove without constricting or obstructing finger movement was key. Motion tracking sensors needed to be micro-sized, flexible and deliver reliable, repeatable results.
The Solution--Polhemus AC Electromagnetics Motion Tracking Technology
Shadow Robot tested several motion tracking technologies to vet the pros and cons of each. After trial and error, they integrated AC electromagnetics, by Polhemus, the Experts in Motion Tracking™. All three challenges were resolved with the Polhemus VIPER™ system, used with Micro Sensors. According to Shadow Robot’s engineering team, small sensor size, high update rates, and the lack of need for line-of-sight is what set Polhemus technology apart from the rest.
What is VIPER?
VIPER™ is the latest motion tracking system by Polhemus. It’s a high-speed, high-fidelity system, with update rates up to 960Hz, fast enough to track the quick hands and fingers of a high-fidelity robot. VIPER delivers latency as low as 1 millisecond, and tracks up to 16 sensors.
Due to the propriety nature of Polhemus magnetic tracking technology, the challenges with line-of-sight occlusions were eliminated. Polhemus technology has the rare capability to track through gloves, walls, clothing, and people.
The Polhemus Micro Sensors slip on and off easily, with optional Micro Mounts, making them the preferred choice for professionals doing hand and finger tracking. The sensors are easily embedded into hardware, clothing or other form factors, and are available with a standard, more rigid cable and a flexible, pliable cable, perfect for hand and finger tracking, or in this case, robot hand and finger tracking.
"You have world-class dexterity from the human-like, five-fingered, robot hand and you can track user fingertip positions and orientations with no line-of-sight required, using the conveniently small and mighty Polhemus sensors."
-Rich Walker, Managing Director, Shadow Robot
Image courtesy of Shadow Robot: The Shadow Dexterous Hand Series
The collaboration of Polhemus motion tracking technology and Shadow Robot’s Dexterous Hand was ground-breaking, paving the way for new, complex applications in robotics. According to Rich Walker, Managing Director of Shadow Robot, “The combination of the precision motion tracking of Polhemus sensors and the renowned Shadow Dexterous Hand from Shadow Robot truly revolutionizes remote working when used in our teleoperation system. The integration of the two leading technologies is a must-have for any researcher in robotics.“
About Shadow Robot
Shadow Robot applies robotics technology to solve real-world problems for people. They’re best known for designing and manufacturing state-of-the-art anthropomorphic robot hands, like the Shadow Dexterous Hand Series, the World’s Most Dexterous Humanoid Robot Hands. Specializing in custom robot solutions, Shadow Robot is experienced in design, development and production. Along with designing and fabricating their latest products, they help clients solve difficult problems with the most innovative robotic systems on the market. They lead with innovation, but stay guided by their ethics, keeping to their strict mantra of creating “robots for good” policy. Learn more about Shadow Robot.
Polhemus is the global leader in high-fidelity motion measurement. They have been helping customers break new ground with best-in-class 6DOF electromagnetic tracking and digitizing systems for over 50 years. Polhemus products are widely used in such areas as: medical applications, university research, robotics applications, including robotics surgery, training and simulation, computer-aided design, virtual and augmented reality, and more.
Case Study: Hybrid VR Dental Training Simulator for Dental Education
Left: GEOTAR-Media, Leonardo Dental Training Simulator Shown, Right: Software interface view of procedure.
High quality dental training education requires consistency, and well-trained faculty and practitioners, along with an objective assessment of skills. Limited resources can pose a challenge for training the volume of dental students necessary. These resource constraints can include budget, a lack of research to be applied in the clinical setting and adequate, qualified teaching staff.
GEOTAR-Media developed a dental training simulator called Leonardo. Leonardo is a dental simulator used for virtual tracking of dental instruments. It was developed as a training solution for dental students, and has a built-in objective assessment.
“The feedback we have consistently received from our customers is they find it to be precise and suitable for the objective assessments they require….People find Leonardo to be a very unique product.”
Alexandra Alekseeva, GEOTAR-Media
How It Works
Leonardo is a hybrid simulator that tracks interventions on teeth models in real time and gives comprehensive feedback of all procedures. Procedures include standard and more advanced skill sets, including
- Taking the history of the patient
- Selecting of anesthesia type, specific to the patient
- Preparing the anesthesia and the accuracy associated with this procedure
- Measuring the percentage of healthy tissues and level of excess movements
- Total time spent and total useful time
GEOTAR-Media Screen Interface, Showing 6DOF Tracking of Dental Tool
Due to the nature of the fine motor skills needed for the dental profession, precision of movement is a key element of the training. Subtle changes in the position and orientation of a dental tool can have a major impact on a patient’s comfort level and patient outcome. Mastering the techniques are critical and creating a realistic training and simulation environment will best prepare students for the work they will do with real patients.
Why Polhemus Motion Tracking Technology?
By using the highly accurate Polhemus 6DOF motion tracking system, the student’s tool is tracked and measured with sub-millimeter accuracy. This is a key element of the objective assessment outcome, as a precise skill assessment can be made using the data provided by the tracking system.
Left: Tool tracks full 6DOF—both position and orientation
No Line-of-Sight Occlusions
There is never a time when the student’s movements are blocked or not tracked due to line-of-sight issues, so no training time is wasted.
Embeddable Technology/Realistic Environment
Tiny Micro Sensors™ are used that are seamlessly integrated into actual dental tools used in the clinical setting. Due to the nature of Polhemus AC Electromagnetic Tracking, system components such as the sensors and the source are fully embeddable. (Photo: Polhemus Micro Sensor integrated into the dental tool).
Being able to use actual dental tools provides the same look and feel students will use in real clinical settings. This provides students with an environment that is most similar to a real-world environment, which is a best practice in any training and simulation experience.
What About Metal and Electromagnetics?
Sometimes, it makes sense when Polhemus sensors are integrated with tools to utilize a tip-offset, meaning the tip of the sensor is moved a slight distance away from the tool.
A tip-offset may be used for multiple reasons. For example, it can be used to avoid the potential negative influence of certain types of metals that may otherwise affect tracking accuracy.
Most times, a slight offset of the tracking sensor, or other work-arounds can mitigate any potential distortion.
(Polhemus Micro Sensor shown with Tip-Offset on Actual Dental Tool)
“Polhemus is the most precise tracking system among all non-optical tracking systems.”
Alexandra Alekseeva, GEOTAR-Media
GEOTAR-Media representative, Alexandra Alekseeva, says other technologies were attempted and most of them were optical-based technologies. They found that optical technologies had many challenges and limitations regarding calibration and ergonomics. They needed a system that you could set up one time, and then turn on and easily get started. After testing a myriad of technologies, GEOTAR-Media found that Polhemus was the best fit for the Leonardo simulator.
GEOTAR-Media is the leader in medical education in Russia. Founded in 1994 as a publishing house, they’ve expanded to have a software division, and have produced over 10,000 books and journals for the medical market. They’ve developed a robust e-library that caters to physicians and medical schools. GEOTAR-Media is a distributor of over 10,000 products from more than 30 vendors around the globe. Leonardo is their signature product, created from years of experience and in-house expertise. GEOTAR-Media covers more than 40% of the entire Russian simulation market. They serve state universities, medical and government institutions, scientific and research institutes and professional societies.
For more information on the Leonardo Dental Simulator, go to: http://www.leonardo-dental.com/
For more information on GEOTAR-Media, go to: www.geotar-med.ru.
Case Study: VSS Vector 21, Virtual Reality Range Finding Binoculars
VSS (Virtual Simulation Systems) required a tracking sensor that delivered full 6DOF (6 Degrees of Freedom) measurement for their Virtual Reality Range Finding Binoculars (Vector 21). The Polhemus G4 was selected because of its full 6DOF tracking, no-line-of sight requirements, and its easy set up and portability.
Vector 21 is a military device used in many countries around the world. VSS, based in Australia, has created a replica of the hardware and incorporated state-of-the-art virtual simulation technology for training purposes. The current standard VR model is a replica of the device called Leica Vector 21, however customization for other types of visual devices is an option.
By integrating Polhemus magnetic motion tracking, VR Binoculars are being tracked in 3D space, with the movement reproduced in the virtual world in real-time. The Polhemus G4™ was selected because of its full 6DOF tracking, no-line-of sight requirements, and its easy set up and portability. The G4 tracker is a wireless product with a small SEU that can be belt-worn, as needed, as the SEU is roughly the size of a mobile phone. The G4 sensor easily mounts on the top of the binoculars. The VR binoculars are plug-and-play, and come equipped with a USB/HDMI connection, as well as a mounting plate for tracking solutions.
The VR Binoculars are great for an array of coordination efforts, including coordination of ground units. It allows the user to know the precise range related to where he or she is looking. The device also has a compass bearing, which reflects the degrees at a precise level. Because Polhemus proprietary electromagnetic tracking is used, the tracking is in real-time, without any appreciable lag time.
There is zero simulator sickness associated with use, not often the case with many other VR visuals powered by other types of technologies.
There are several benefits to using the VR Binocular training device. By replicating the user experience virtually, there are significant cost savings, by preserving the utilization of human resources and necessary training materials that would be used in a typical mock training experience. The time alone involved in properly setting up such an experience is significant. Also, using virtual methods allows for introducing less common or more challenging training scenarios that are not practical to set up in a live training exercise.
The Vector 21 VR Binoculars can be used with a dome screen, or can be an integral component in a full simulator, such as a sniper or a JTAC simulator. It can also be used completely by itself, depending on the training objective.
Other training capabilities for Vector 21 include: call for fire, close air support, target description exercises, information gathering, battlefield commentary, and much more.
VSS (Virtual Simulation Systems) is a groundbreaking company, developing new and custom solutions for both military and civilian simulation needs. They offer an innovative range of products in the synthetic training realm and are constantly developing new technologies to meet cost-effective outcomes. VSS designs and builds custom simulators, full procedural or part task trainers to suit any needs at any budget. These range from vehicles to aircraft, projection domes to virtual displays and more. They offer Commercial Off The Shelf simulators that are modular and can be combined or customized in many ways. Visit: www.virtualsimulationsystems.com for more information.
Case Study: VSS Case Study: MK2 Sniper
VSS (Virtual Simulation Systems), out of Australia, wanted to create a training and simulation product that would cater to soldiers using scoped weapons for applications such as sniper shooting. They sought to provide the most realistic training experience possible. Because of the nature of sniper shooting, and the precision skill level that is necessary, a high-fidelity tracking system was an absolute must for a realistic sniper simulator. They accomplished this by using their dynamic software and integrating the Polhemus G4™ tracking system.
VSS created the MK2 Sniper Simulator. Its development is the result of close collaboration with VSS and the Australian Defense Force. The MK2 offers a wide range of uses and capabilities. Capabilities include: sniper team engagement, tracking and engaging realistic moving targets, mil-dot holds on linear targets, rapid re-engagements, and missed target drills.
One of the most important and unique things about the MK2 Sniper training is that it can be used with a soldier’s own field weapon. This eliminates inconsistencies with training when using different hardware, such as varying degrees of trigger pressure and differing weapon weight distribution. Using the MK2 Sniper with a soldier’s actual service weapon is simple. The MK2 is compact and easily attaches to the front of their existing scope. With the Polhemus G4 sensor mounted on the weapon, its movement is tracked in full 6DOF, so both position and orientation are tracked seamlessly.
The trainee views the magnified virtual world through the scope, just as they would in live training or operations. When shots are fired, this is reflected in real time using simulation software by VSS. The software offers dynamic real-world location scenarios, and ballistic effects that are accurately modeled and replicated. The high-fidelity tracking technology, combined with the VSS software creates an engaging virtual world and delivers a complete and realistic training solution.
The Polhemus G4 motion tracker is an integral part of this total solution. Because G4 tracks in full 6DOF with a high degree of accuracy, trainees are able to practice as they would perform in a live operation.
The MK2 Sniper Simulator can be used by itself as a sniper training tool, or additional components can be added. Adding VR binoculars or modular projection domes enhance the product capabilities further, enabling additional inputs and layers to be added to the training experience.
There are numerous benefits to using the MK2 Sniper Simulator. Training in a virtual environment allows for a conservation of material resources; without the need to shoot countless rounds of live bullets during training sessions, significant cost savings are achieved. Additionally, a virtual reality training environment is by far the safest setting for training soldiers, eliminating the possibility of accidents, and providing the ability and option to do virtual training runs prior to live training.
Another major benefit is flexibility. Previously, training in specific, complex environments were a challenge due to cost constraints, available manpower and location settings. With MK2, the environment is replicated via the software, and the real-time tracking enables a training experience that mimics a live operation environment like never before.
- How does the tracking work? Learn about our AC Electromagnetics
- Contact email@example.com for product information.
Case Study: VSS VSS Case Study: M134 Dillon Minigun
In the virtual environment, the Simulated M134 Minigun training system is set up with the Polhemus G4™ motion tracking system. Because the tracking system is true 6DOF, the sensor tracks both the position and orientation of an object.
When it comes to finding ways to save money on military training, operations that use heavy ammunition are among the top of the list. VSS (Virtual Simulation Systems), out of Australia, developed the Simulated M134 Minigun. It’s a full-size replica of the original M134, made to deliver the most realistic training experience possible, while enabling a significant cost savings for military groups (Polhemus sensor shown on top of the VSS M134 Minigun).
The actual live weapon, the Original M134, is a high powered, six-barrel machine gun. Featuring a Gatling-style rotating barrel, this powerful military weapon can shoot rounds of ammunition at a high rate, with a rate of fire up to 6000 rounds per minute. This volume of ammunition is extremely costly for each training exercise.
Used with the Polhemus G4, the Simulated M134 Minigun significantly cuts costs by not firing live rounds, yet provides the various scenarios in a virtual environment to prepare trainees for live operations.
Besides learning how to lead their firing, trainees also learn the skills necessary to lead the target, which isn’t always intuitive, and takes practice. They also learn how to react in various situations, including maintaining safety precautions, and what to do in case there are equipment malfunctions in a live operation.
The Simulated M134 is an accurate depiction of the live weapon with all of its functioning parts and if any critical part of the weapon is disabled in any way or removed, the weapon will not allow the trainee to fire. With features such as force feedback during fire and dry firing with high frequency vibration module, trainees get a fully simulated experience.
Originally targeted for use by the U.S. Army, the live mini gun can be mounted on humvees, but is primarily used on helicopters. In the virtual environment, the Simulated M134 Minigun training system is set up with the Polhemus G4™ motion tracking system.
Because the tracking system is true 6DOF, the sensor tracks both the position and orientation of an object. In this case, a sensor is attached to the gun and a second sensor is attached to the HMD equipped helmet. Viewing the virtual scenario through the HMD, the trainee’s head movement is tracked, along with the gun movement.
Besides saving on ammunition costs, another cost benefit with simulated training is the aircraft never leaves the ground; this saves on fuel and aircraft maintenance, as well as the travel costs involved with sending an entire training crew for a training mission. With less time in the air, there are also environmental benefits.
The M134 is available with composite plastics or metal construction. It is available to system integrators or as a full stand-alone simulated training solution by VSS.
VSS (Virtual Simulation Systems) is a groundbreaking company, developing new and custom solutions for both military and civilian simulation needs. They offer an innovative range of products in the synthetic training realm and are constantly developing new technologies to meet cost-effective outcomes. VSS designs and builds custom simulators, full procedural or part task trainers to suit any needs at any budget. These range from vehicles to aircraft, projection domes to virtual displays and more. They offer Commercial off the shelf simulators that are modular and can be combined or customized in many ways.
Case Study: VSS CATS, Complete Aircrew Training System
By attaching G4 sensors to the aircrew helmets, both position and orientation are tracked. Crew members can walk about the mock cabin freely, even passing in front of one another, with each trainee being tracked continuously.
Simulated training has expanded into many areas, but there seems no better use of this type of training when it provides the kind of experience for jobs that save lives. Training highly skilled and effective aircrews for an array of operations is a dangerous endeavor, and a costly one. VSS (Virtual Simulation Systems), out of Australia, has created a cost-effective solution for procedural aircraft crew training that provides a safe method and allows for training on complex operations, including rescue missions. This total solution is the CATS (Complete Aircrew Training System).
CATS is used for training in more than ten locations around the world. It’s utilized by the Australian Defense Force, the European Defense Agency, the UK Ministry of Defense, and has also aided in civilian training by its utilization of the rescue provider, Priority 1 Air Rescue.
A break-through in aircrew training, CATS provides a realistic training experience that would not otherwise be possible. By equipping crew members with virtual reality headsets, their positions are tracked in 3D space in 6 Degrees-of-Freedom. By combining dynamic software by VSS, this allows the trainees to be completely immersed in a high-fidelity representation of the aircraft and any cabin.
This is accomplished with the integration of Polhemus G4™ which uses electromagnetic motion tracking. By attaching G4 sensors to the aircrew helmets, both position and orientation are tracked. Crew members can walk about the mock cabin freely, even passing in front of one another, with each trainee being tracked continuously. With Polhemus motion tracking technology, a line-of-sight is not necessary for tracking, so there is no interruption of data. As long as the sensors are within the range of a Polhemus source, seamless 6DOF tracking is achieved. Watch the CATS video here.
The Polhemus G4 tracking system is also scalable, so sources or sensors can be added to increase the range or the number of people or objects tracked. The high-fidelity tracking creates a high-quality VR experience.
A wide variety of operational environments are available with CATS, including coastlines, forests, mountains, western cities and afghan villages. Training can be tailored to the specific needs of the user and any geo-specific training area can be implemented. Several modular options are available including, but not limited to: door gunnery, hoisting and winching, marshalling, and a cockpit module.
When VSS released CATS, they set the standard for simulated aircrew training. Aside from it enabling a high cost savings, trainees gain experience in dangerous missions that are hard to replicate in live training. They also train over terrain they would only see in a live mission, and every CATS simulated training session allows for a safe experience where all trainees come home.
VSS continues to develop a wide array of simulation technologies and they are constantly innovating to deliver dynamic solutions that evolve as fast as training needs do.
VSS (Virtual Simulation Systems) is a groundbreaking company, developing new and custom solutions for both military and civilian simulation needs. They offer an innovative range of products in the synthetic training realm and are constantly developing new technologies to meet cost-effective outcomes. VSS designs and builds custom simulators, full procedural or part task trainers to suit any needs at any budget. These range from vehicles to aircraft, projection domes to virtual displays and more. They offer Commercial Off The Shelf simulators that are modular and can be combined or customized in many ways. (Photos Courtesy of VSS).
Case Study: Bull 3D System Using the Polhemus G4
There are plenty of people who seek to improve their recreational golf game, and then there are those who need to understand their precise body movements and how this affects every aspect of their game. Mark Bull, owner of Bull 3D out of the UK, caters to the latter audience. Combining his biomechanics expertise with the latest cutting-edge technologies, he provides precision, expert-level analysis for exceptional golf performance development.
As a young athlete, Mark Bull was a high-level, respected golf player. After sustaining an injury, he became fascinated with biomechanics. He combined his love of sports, anatomy, and science to become a leading biomechanist and PGA professional who enables players to unlock their full potential. He has been offering his world-class services since 2001 to various level athletes, including several top major players.
Bull devised the Bull 3D System, utilizing the Polhemus G4™ motion tracker from Polhemus. Strategically placed sensors provide full 6DOF precision data for selected points, detecting the slightest movement, and capturing both position and orientation of the user.
With a system electronics unit the size of a mobile phone, G4 is compact and can be belt-worn. No cameras of any kind are used in the motion tracking, as the system uses Polhemus electromagnetic technology. This means there is never a break in the line-of-sight. The user has full freedom of movement, and with every golf swing, the system produces a continuous data stream, with no interruptions.
Bull couples the Polhemus hardware with sophisticated software, providing a wealth of information. It allows for a true understanding of how joints and segments move in golf and in real-time. Also, learned, are intrinsic values such as speeds, the force produced, acceleration/decelerations, elastic recoil and angular velocity. This data allows for instantaneous discussion with the athlete and their coaching team.
Through the use of audible biofeedback, real-time improvements can be made, allowing for immediate changes for both short and long-term gains. This makes each session highly impactful to both the user and their coaches.
According to Bull, the main difference in his system, compared to others on the market, is the intellect behind the data. First off, the data has to be highly accurate and produce repeatable results. The Polhemus G4 system accomplishes this piece. Secondly, knowing how to interpret and apply the data is critical. In any given session, this always proves proves to be the biggest skill needed. Watch the systems in action here.
"For my objectives, there are no limitations for what the Polhemus G4 motion tracker can do and the functionalities are superb." Mark Bull
Bull has been using Polhemus technology since 2005, but says G4 was a break-through because it allowed the freedom and ability to easily capture precision body movement both indoors and out. The tetherless G4 tracker allows him to bring the portable system to the user’s actual environment. Bull says this is vital for high-aspiration athletes and professionals he works with, both in the studio and on the golf course.
Injury prevention is also a major part of the program and mission, and is the priority in most sessions. Bull’s PhD work reviewed body structures and their correlation to swing patterns. He says this is among the best uses of the data. He uses his analysis and creates training programs that best avoid paths to pain and help rehabilitate an injury, if necessary.
Bull has worked with many high level golf players, including several major champions. The clients span is around the globe, including the UK, the U.S., Australia, Europe.
As far as what’s ahead for Bull 3D, he is exploring expansion into multiple sports in the immediate future. In other biomechanical applications, Bull connects the G4 to other measurement devices, such as force platforms and launch monitors. This allows for correlating the data for a much greater understanding of how the athlete is moving and behaving.
After researching a variety of solutions, Bull says, “The portability, credibility and functionality G4 offers, combined with each user’s education, philosophies and experiences provides a wonderful correlation. Each client situation is unique. Because of the adaptability of the G4 tracking system, along with all the other elements, each client is truly their own separate case study."
Case Study: Polhemus G4 in Virtual Rehabilitation
At the Union de Mutuas Rehab Unit in Valencia, Spain, some patients actually look forward to physical therapy. Thanks to BioTrak, a virtual reality rehabilitation system, repetitive physical therapy movement has now turned into a customizable, fun and challenging game for patients—and an efficient cost savings tool for the clinic. The latest electromagnetic motion tracker, G4™ by Polhemus, is the technology powering this VR system that focuses on rehabilitation.
The system, BioTrak, has a simple set up, consisting of a video display (a screen, projector or similar), a standard PC to run the software application and the Polhemus G4 electromagnetic motion tracker. The G4 system consists of the following components: the systems electronics unit, (hub), an electromagnetic source, and one or more sensors, the humeroscapular recovery application utilizes three sensors that are attached to the wrist, elbow, and scapula.
Ismael Estudillo is the CTO of Bienetec in Valencia, Spain. He describes the VR rehab game, “The application shows a virtual scenario where different colored jelly items rise from the floor. G4 allows the application to represent the patient’s feet and to transfer their movements to the virtual world. The mechanics of the application is very simple; it consists of stepping on every item with one foot, while keeping the other one still.” The initial game was created very simply to test the system—more complex versions are currently being developed.
The entire VR application has proven to be a robust system, and is currently used by therapists at different locations from 8:00 am to 8:00 pm, with few breaks in between. It provides enough interest to keep patients motivated and on schedule with their rehabilitation efforts, paving the way for cost efficiency and a speedy recovery.
Why Polhemus Electromagnetic Motion Tracking Technology?
Electromagnetic motion tracking was selected for the VR rehab application because of its affordability, ease of set-up and ability to produce repeatable results. Other technologies, such as optical systems, present line-of-sight issues, which are impractical for a typical PT clinic set-up.
Camera technology can sometimes be cost prohibitive and is known to have too many environmental limitations, such as ambient light control. Camera technology also lacks the portability that BioTrak offers.
Polhemus electromagnetic motion tracking was the perfect solution. The Polhemus G4 was chosen because of its wireless communication system, which allows for freedom of movement. Also, the set-up is simple and portable—just turn it on and start tracking. All of these factors made Polhemus motion tracking technology ideal for PT environments; the system has aided in the specific areas of balance recovery and musculoskeletal rehabilitation.
Polhemus Sensors Attached to Patient Using BioTrak Application For Musculoskeletal Application
According to Estudillo, several factors have made this virtual reality system effective for the rehabilitation application:
- Efficiency as a clinical tool: since it has been designed by clinicians and since it is based on the motor relearning principles, this VR Rehabilitation system can be considered a powerful tool to improve balance control of patients.
- Ease of use: BioTrak includes a friendly user interface from the point of view of both clinicians and patients.
- Customization to patient’s needs: BioTrak can fit each patient’s impairment to provide a custom rehabilitation session to each patient.
- Motivation: BioTrak provides enjoyable and motivating task-oriented exercises.
Dr. Felicidad Calduch, Head Physiatrist of the Rehabiliation Service, sees the benefits derived from the use of the system being twofold: “We’ve been using BioTrak during these last five years, from the development of the first prototype to its actual configuration. From a physician’s perspective, BioTrak facilitates balance rehabilitation according to the motor learning principles and accelerates the process of regaining postural stability to humeroscapular mobility. From the patient’s perspective, the process of rehabilitation becomes more enjoyable, fun and challenging without losing efficiency.”
Before BioTrak was implemented, no other virtual rehabilitation devices were being used by the clinicians at Valencia hospital. The treatment for musculoskeletal injuries was performed using traditional physical therapy. These methods were costly, tedious and time consuming, and the volume of patients was a challenge.
Dr. Felicidad Calduch has found that BioTrak has proven to be cost efficient. “The recovery of musculoskeletal injuries has a tremendous impact in terms of functional independence. The use of BioTrak has allowed us to shorten the length of stay of our hospitalized patients, since it facilitates a greater and quicker acquisition of global mobility and functionality in terms of activities of daily living. Besides, the benefit of BioTrak in terms of usability, it can be easily located in a traditional rehab unit and the set-up parameters for a complete rehab session can be easily configured. This makes BioTrak an excellent option from a cost saving perspective.”
Dr. Juan Gala, Medical Director of Union de Muturas and CEO of INSALUD, commented on the use of BioTrak, “From a physical therapist’s view, BioTrak represents a new and promising rehabilitation tool to deal with one of the most common and most dysfunctional deficits after several pathogies with high incidence and prevalence rates, such as musculoskeletal injuries or brain injuries. The system is versatile enough to meet each patient’s needs in terms of motor dysfunction.”
Patient Feedback is Key
Gala has seen the benefits first-hand and stated, “Other aspects of the VR system, such as “Patient Feedback,” which increases the challenge perception of the patients, and the “Results Menu” which gives an accurate and useful view of the rehab processes are clear, positive aspects of this device. In our experience, intensive treatment with BioTrak has significantly improved the balance, stamina and speed of movement of most of our patients. Moreover, most of them found their rehab sessions motivating, fun and challenging, which has even more relevance in patients with long-term rehabilitation processes.”
"BioTrak helped me a lot during my recovery after a stroke. I worked on both strength and balance and I could walk much better to the point of leaving the crutch that I usually needed. I also was able to work on the coordination of my movements.” ---Rehabilitation Patient, Neurorehabilitation Service of Hospital NISA Valencia al Mar
BioTrak is a tool based on virtual reality technology which integrates in a single platform training exercises for the rehabilitation of certain body functions that have been depleted or lost due to various pathologies. BioTrak´s technology allows the patients to interact in a virtual environment where they are challenged to fulfill simple tasks by means of their own movements. The system motivates patients in order to improve their adherence to the treatment, and serves as a very efficient tool in their process of recovery. BioTrak is a product marketed by Bienetec and devised by LabHuman. Photos Courtesy of Bienetec
Case Study: PATRIOT Used In Volkswagen Spray Paint Gun Color and Trim Exhibit
Polhemus technology powers a vast array of virtual reality simulators, so when OmniMedia was faced with the challenge of creating an interactive virtual reality exhibit, the solution was the Polhemus PATRIOT.
Volkswagen Spray Paint Gun Color and Trim Exhibit
Challenge: OmniMedia was charged with designing an interactive virtual reality exhibit using a spray paint gun to engage attendees for an automotive trade show. The George P. Johnson Company of Auburn Hills, Michigan, contracted with OmniMedia to work on this project. Polhemus sensor shown in image embedded in the spray paint applicator.
Solution: Howard White, President of OmniMedia, looked for a 3D motion tracking device that could be used with a commercial spray gun to provide the most realistic virtual experience. Initially, a primary concern for White was finding a tracking device that had the robustness needed for the application.
Given that the show was a large, well-attended event, he knew the device would get frequent use, and thousands of people would be handling it on the trade show floor. White needed tracking technology that provided reliable, repeatable results; he also needed it to work seamlessly with multiple units within the show floor space. The tracking device also had to measure position and orientation, given the nature of the application with the spray paint applicator.
After exploring options, White decided on the Polhemus PATRIOT™ motion tracking product for his spray paint exhibit. Because Polhemus technology is electromagnetic-based, line-of-sight is not necessary. This makes Polhemus technology the top choice when an application calls for embedding sensors, as done in the spray painting exhibit.
With the sensors embedded into the spray paint applicator, White was able to achieve the most realistic virtual reality environment to illustrate the spray paint application.
Booth visitors pulled the spray gun trigger to start each unique experience; they selected a car, chose a color, and began spraying. They transformed their virtual car from blank white to an accurate, current color of their selected VW model.
By using Polhemus magnetic sensors with high accuracy and low latency, a very realistic experience was successfully created. To enhance the total virtual experience and add realism, sensory inputs wereadded, such as switches and speakers.
Polhemus proprietary technology measures both position and orientation, enabling the sensor to track where a person or object is at any time in 3D space. Multiple PATRIOT systems were used concurrently in the same space without cross-talk interference, due to multi-channel operating capability.
Because the nature of spray painting requires the user to twist and turn the spray gun in various positions, true 6DOF technology is the only way to achieve this. For this reason, spray painting is a great way to easily illustrate what 6DOF technology actually means and what it does.
Unlike camera tracking options, Polhemus sensors do not need a field of view in order to track motion; this is why they can be embedded into a custom form factor.
Howard White, of OmniMedia, was pleased with how the project turned out and said, “We have produced multiple versions of this interactive exhibit; it’s been highly effective and has been used in auto shows all over the US, including Miami, Portland, Boston, Cleveland, Atlanta and more.”
OmniMedia engages audiences through innovative and interactive multimedia. From iPad apps to motion activated exhibits and arcade-style games, they create inspiring content and deliver world-class installations. They take the client’s vision and create attention-getting, robust designs that last. (Images courtesy of OmniMedia Group).
Case Study: FastSCAN Used to Improve Crop Yields
The Polhemus FastSCAN™ laser scanner supplied by advanced visualization company, Virtalis, is playing a vital part in an international study to improve crop yields.
Dr. Erik Murchie, Lecturer in Crop Physiology, Division of Plant and Crop Sciences at The University of Nottingham in the United Kingdom explained, “It’s all about analyzing the ratio of light intercepted or ‘captured’ by the crop to the amount of biomass produced. In order to do this, we’ve got to study the architecture of the rice and wheat canopies at quite a fine scale. For example, if we can open up their canopy, we’ll get more light to the plant tissues and optimize its photosynthesis. With their complex, curved leaves, these plants have proved very difficult to measure over large areas."
"We’ve been successful using FastSCAN in the lab and are now deploying it in field trials in Mexico." Dr. Erik Murchie
Polhemus FASTRAK Unit Embedded in FastSCAN
The FastSCAN acquires 3D surface images when the handheld laser scanning wand is swept over an object, in a motion similar to spray painting. FastSCAN works by projecting a fan of laser light on the object while the camera views the laser to record cross-sectional depth profiles.
FastSCAN has an embedded Polhemus FASTRAK® unit, which determines position and orientation, enabling the computer to reconstruct the full three-dimensional surface of the object. Its non-contact methodology is important when dealing with humans, animals and plants as well as valuable or fragile objects.
Qingfeng Song, a PhD student in Plant Systems Biology at Shanghai Institutes for Biological Sciences in China, has just returned from Mexico where he sought to measure photosynthesis rates in different varieties of wheat by taking slices through the plants’ canopies.
According to Song, FastSCAN had never been used for this kind of application before and so they had to experiment with the best way to use it out in the field.
"By working in low light levels at dusk and without destroying the plants, I was able to capture data over a large area for the team to study. Such data are required for the development and validation of a realistic 3D canopy photosynthesis model," said Song.
This case study published with Permission and Courtesy of VIRTALIS
Case Study: FastSCAN Critical Tool in Restoration and Replication Project
Jim Turner, owner and founder of Honeoye Falls Millwork was approached to be a part of the restoration and replication of an 18th Century Pipe Organ known as the Craighead-Saunders organ project. This historic organ had been declared a national treasure and no original parts are permitted to leave Lithuania. The Polhemus FastSCAN was instrumental in this complex project.
Jim was challenged by the fact that he needed 3D models of the pieces that made up the organ, to then bring back to the US in order to replicate the original.
Realizing he needed a 3D scanner Jim evaluated many, and chose FastSCAN™ for multiple reasons including portability, ease-of-use, quality of scans and most impressive to Jim, the auto stitching functionality.
Some pieces were not allowed to be moved, and in some instances touched, it was crucial to have a portable scanner that was easy to set-up. Jim had to reach pieces where no other scanner could have been setup. FastSCAN’s handheld wand easily moved around, above and below the large and irregular pieces as needed to capture a complete scan.
While scanning the life-sized angel, as seen in the photo above, Jim explains, “I was set up on a platform scanning the life size angel and the entire platform was moving with every step, but with the transmitter strapped to the angel, the scans came out fine”.
Other pieces were moved to a scanning station which was a ping pong table in the back area of the church, dirt floor, and no lights except a large window. Jim was able to scan about 66 pieces in 4 days.
Portability was essential: “FastSCAN was the only scanner that was portable and robust enough to be set-up on a piece of scaffolding for me to scan this life size angel free-hand." – Jim Turner
The organ is made up of "pipe shades", ornately carved baffles that go at the top and bottom of a set of pipes, restricting the airflow and modifying the sound of the organ. The photo is an example of the pipe shades Jim was tasked in replicating. This pipe shade measures 74" long and 34" wide.
Jim scanned the pipe shades which created a 3D model within the FastSCAN software exported the file from FastSCAN to his CAD/CAM software to create a toolpath he then sent the toolpath file to his milling machine for carving.
Total carving time was about 23 hours: 11.5 hours for the roughing cut, 1.5 hours for preliminary finishing, and 10 hours for final cut. Both the front and back of these parts were carved to match the originals.
“I could not have done this project without FastSCAN. The parts came out exactly like the originals, and I was able to stay within the customer’s budget.” Jim Turner
Case Study: New Wave Woodworking completes complex restoration project with FastSCAN
Rudy was looking for a portable 3D non-contact laser scanner to have the ability to reverse engineer quickly and easily and produce high quality furniture fast. Rudy found the solution with FastSCAN from Polhemus.
Rudy Schemitz, custom manufacturer of furniture and owner of New Wave Woodworking Inc., located in Honesdale, PA, is a pioneer, taking woodworking to a new level with the Polhemus FastSCAN. Woodworking has always been a part of Rudy's life, and he was taught early on by the best craftsmen of his time. Rudy has modernized aspects of the woodworking industry by utilizing new technology, allowing him to bring his business to innovative heights.
Rudy was looking for a portable 3D non-contact laser scanner to have the ability to reverse engineer quickly and easily and produce high quality furniture fast. In the course of his search he came across the Polhemus FastSCAN, a lightweight, handheld, portable solution for real-time 3D laser scanning.
He learned that FastSCAN exports to most popular software packages using common file formats such as STL, IGS, OBJ, DXF among others. He also realized these file formats can be imported into various software packages for use with CNC and multi-axis mills.
Upon evaluating other laser scanners, Rudy chose FastSCAN because of its quality, portability, reasonable price and customer support. Portability was a key factor.
It's often not possible to bring large or immobile pieces of furniture to a stationary scanner station. This portability allows the woodworking team to bring the scanner to the customer job site for quick and easy scanning of complex 3D surfaces.
With FastSCAN, the rapid prototyping process involves scanning a custom built frame, molding, or piece of furniture using the FastSCAN laser scanner, then exporting the file format of choice into one of many software packages available: Rhino®, Clay Tools from Sensable Technologies,VisualMill, ArtCAM, and/or other industry CAD tools.
Within the chosen CAD tool/software, the file can then be manipulated and saved before being exported to a CNC or multi-axis machine for carving. The FastSCAN also allowed Rudy to digitally 3D archive his custom pieces he had built for future file access rather than a paper document retrieval system.
A hand carved leg was scanned using FastSCAN. It was then converted to an STL file and stacked on an X axis in a CAD program to produce a total of 12 legs. The file was exported into a CAM software package and was then able to bring that file to the carving machine. When finished, the board is flipped over, and the bottoms are then milled.
When finished, the pieces out of the stock on a bandsaw were then cut. They were held in place by 1/2 inch dowels that are modeled into the legs during the CAD process. The hand carver then cleans up the legs and gives them the final detail that the carving machine missed.
To carve the scanned leg by hand it took a little over 4 hours from start to finish. To scan that leg, write the programming, machine and finish carving the 12 legs took just about 8 hours.
"Bottomline, FastSCAN saved us a little over 40 hours of hand carving time", says Guy Mathews, 3D/CAD/CAM Division of New Wave Woodworking Inc.
Before Rudy discovered FastSCAN, the process involved digitizing pieces with a 3D digitizer. Although this method is a common and very effective method, the digitizing process can be time consuming and sometimes limiting, depending on the size of the piece being digitized.
With Rudy's leap into new technology and skillful thinking, he has been able to build his business to a greater capacity, not to mention achieving prominent status within the woodworking industry.
"We are delighted with FastSCAN, your customer support and your company as a whole," states Guy Mathews.
Case Study: Mixed Media Artist Uses FastSCAN For Rapid Prototyping of Art
Vivian Pratt, a mixed media artist, combines technology and various media methods with her traditional wood carvings, creating 3D rapid prototype reproductions, playing the traditional against the cyber-sculpture, resulting in an energy and tension not possible with a single sculpture. Vivian creates her wood sculptures using roots and driftwood, then carves, adds and forms pieces to create the finished masterpiece. Vivian's art features fantasy creatures, part human, part animal with allusions to dragons and gods.
The technique of creating an original wood sculpture can take weeks to complete. Once it is finished, this sculpture is then scanned with a Polhemus FastSCAN system. FastSCAN is a lightweight, handheld, portable 3D scanner creating real-time images.
The scanning process is fast, taking as little as just one minute, depending on the complexity of the sculpture. The file can then be saved in multiple file formats such as STL, IGES, OBJ, DXF and many others, for easy importing into a CAD or modeling software of choice. In this particular case Vivian exports into Maya®, and is then able to modify the scan for complete customization.
Vivian tailored this particular scan adding frill to the neck and removing certain attributes in order to resemble a female unicorn (see printed model image; actual artwork shown with two sculptures). The customized model was then produced with a Dimension printer at a reduced scale. After putting weeks of work into each sculpture, with a simple scan Vivian has the ability to customize and reproduce her art using a rapid prototyping system.
Using FastSCAN not only saves time, but offers options such as scaling and digital archiving which are not available with traditional methods.
Case Study: Joint Mongolian-Smithosonian Deer Stone Project using FastSCAN
The Polhemus FastSCAN laser scanner was used to make 3D record of archaelogical data from deer stone site investigations.
Documenting the deer stones includes photography of all sides with color and scale indication, drawings, condition notes, and, for the first time, 3D records of individual monuments, all of which are intended to complement the detailed mapping and archaeological data from deer stone site investigations.
The northern Mongolian province of Hovsgol Aimag has been the focus of collaborative research, coordinated by the Arctic Studies Center and its director, Dr. William W. Fitzhugh (Smithsonian's National Museum of Natural History) since 2001. In its investigations of the region's connections to arctic cultural history, the Joint Mongolian-Smithsonian Deer Stone Project (DSP) has included archaeological studies of "deer stones" and the ritual contexts in which they are found.
Averaging 1-3 m in height, these upright stone slabs are characterized by low-relief carvings of deer with flowing antlers. Over 550 have been identified thus far in Mongolia's grassy steppe region, occurring singly, in small groups, or concentrated in larger groupings, often in association with stone burial mounds, called khirigsuur. These monumental features have generally been dated to the Late Bronze to Early Iron Age, approximately 3000 years ago.
Geographic isolation has hampered systematic documentation and archaeological investigation, and very little still is known about the deer stones' age, function and meaning within their social, cultural, religious or artistic contexts. Endangered by unprotected exposure to harsh environmental conditions and increasingly by human causes, the deer stones are now considered among the most important - and threatened - archaeological treasures of Central Asia. This has placed a high priority on efforts both to understand and preserve these national icons, and has framed the documentation component being undertaken by MCI.
Documenting the deer stones includes photography of all sides with color and scale indication, drawings, condition notes, and, for the first time, 3-dimensional records of individual monuments, all of which are intended to complement the detailed mapping and archaeological data from deer stone site investigations.
The priority for the ACP conservation team during the June-July field season was testing a portable hand-held 3D laser scanner for use in the field. This technology allows dimensional and topographic information to be recorded rapidly and accurately in digital format without directly contacting the object's surface. The digital files can be displayed graphically and can also be exported to specialized milling machines to create high-resolution 3D models.
Once the logistical aspects of scanning under extremely rustic conditions were worked out, Rae Beaubien, Vicky Karas and Carolyn Thome were able to scan 10 deer stones at four sites, using locally available materials to construct temporary shade shelters over the deer stones and a small generator to run the scanner and a laptop computer.
Three of the sites were located around Lake Erkhel, about 30 km north of Muren, the region's major town, including the tallest one known to date (3.8 m); and Erkhel North and Erkhel East, with two deer stones each.
The team ultimately required only two to three hours to completely scan a deer stone, including the time to set up the shelter and equipment.
Case Study: Digital Archives of Star Wars Artifacts Created with FastSCAN
The studio was tasked with the immense project of creating a digital archive of the 1977 Star Wars artifacts. A team of technicians from Gentle Giant was allowed access. "The FastSCAN was critical to the project," says Steve Chapman of Gentle Giant Digital.
Gentle Giant Digital is a world-leader in digital 3D scanning for toys, games, & film, and a division of Gentle Giant Studios founded in 1994 and based in Burbank, California. Gentle Giant Digital use a wide range of scanning equipment allowing them to digitize full body, heads, props, maquettes, vehicles and movie sets, and provides a mobile digital service.
Gentle Giant selected the Polhemus FastSCAN™ Cobra™ and according to Karl Meyer, owner of Gentle Giant, "It has proved to be a key component. The FastSCAN has completed our arsenal." Recently, the studio was tasked with the immense project of creating a digital archive of the 1977 Star Wars artifacts.
A team of technicians from Gentle Giant was allowed access to the famous Lucasfilm archives at Skywalker Ranch where they digitized props, models and costumes, everything from Han Solo's blaster to the original Imperial Walker model.
The FastSCAN Cobra is a lightweight, handheld laser scanner, which you sweep over an object – just like spray painting. This lets you scan those hard to reach places other scanners cannot, as Steve reported from the set of Star Wars III in Sydney: "In fact we have never been able to scan rubber prosthetic masks effectively in the past because of under-cutting fill-in from our head scanner."
"FastSCAN was critical to the project." Steve Chapman of Gentle Giant Digital
As you scan, the 3D image appears on the computer screen in real-time. The finished scan is then processed by the FastSCAN software to combine any overlapping sweeps, significantly reducing the time to develop surface models. "We love our Polhemus scanner," says Steve. "In fact the creature department on Star Wars III loved it so much that their entire crew often spent their down-time scanning their own creature creations."
From the set of Harry Potter III in London, Steve said, "The scanning wand has been able to get data from objects we could not conceive of scanning with any other gear." They were able to scan an eight foot tall werewolf among other items on the set. Steve emphasized, "I don't know how we could have done it without your scanner."
Case Study: FastSCAN Lets You Race Through Reverse Engineering
Using the Polhemus FastSCAN, a laser surface scanner which creates 3D models, MWDesign was able to streamline the reverse engineering process for vehicle conversion from left hand to right hand drive for Bunce Motor Company.
As published in Time Compression Technologies, FastSCAN streamlines the reverse engineering process for vehicle conversion from left hand to right hand drive for Bunce Motor Company. A typical conversion can take up to eight months, but with their newly acquired hardware and software knowledge, MWDesign anticipates bringing the entire conversion process down to one working week.
MWDesign was selected to provide a 3D model digital scan and reverse engineer all internal components of a Corvette, including changing the windshield wiper direction from right/left to left/right. The reverse engineering module "REX" (Reverse Engineering Extensions) from Pro/Engineer® was used to import and process the scan data. After stripping the vehicle down to its essential components for the conversion, the dash console and the center console were ready to be scanned.
Technical expertise for the scanning process was supplied by ARANZ Scanning Limited. All metal components from the dash were removed and the dash was sprayed with a contrast-enhancing agent to give the black dash a more scanable surface. ARANZ scanned the whole dash at a resolution of around 0.5 mm. Post processing with FastSCAN created a high-resolution water-tight STL file for importing into Pro/Engineer.
At the resolution used, the grain in the leather upholstery was clearly visible in the raw data. Although FastSCAN can calculate finer data points, the size of the resulting file for such a large component was the limiting factor.
The STL file was imported into Pro/Engineer and using features available in their reverse engineering extensions module "REX" a parametric model was created and saved as a Pro/Engineer file. The data was then split into two parts: upholstery and structural. As the upholstery surfaces were organic in nature, they needed to be offset by 3.5 mm to allow for foam padding and upholstering of the new dash. The structural part was constructed from a morph of flat planes and simple surfaced forms, requiring a high degree of accuracy as a number of other components are located within the dash structure.
The two-part assembly was finally re-combined to form a third completed model part. While maintaining integrity and stability, the file size of this model was able to be reduced by over 30% using Pro/Engineer's "Publish Geometry" command.
The two methods of surfacing resulted in a clean and robust model that allowed manipulation of the non-symmetric features such as heads up display, gauge console mounting and the Corvette logo over the passenger air bag.
The re-combined dash surface files were exported to a five axis CNC router. The dashboard was machined in high density closed cell foam 1.5 mm undersize to allow the patternmakers at Bunce Motor Company to build up the surface with 2 layers of fiberglass allowing a better finished surface from which to form the master molds.
The total conversion time was reduced to four months by utilizing the FastSCAN system and the other techniques described. MWDesign anticipates bringing the entire conversion process down to one working week.
With an established process in place, and their newly acquired hardware and software knowledge, MWDesign is preparing to develop interior conversions for a Dodge pick-up and a Hummer.
ARANZ Scanning Ltd is a wholly owned subsidiary of ARANZ (Applied Research Associates NZ Ltd) which was formed in 1995 specifically to develop and commercialize the patented technology used in its very successful hand-held laser scanner. The scanner now known as the Polhemus FastSCAN has found application in animation and graphics, prosthetics and orthotics, forensics, medicine, archaeology, bio-sciences, and reverse-engineering. www.aranz.com
MWDesign specializes in product design, managing the project from concept to production. MWDesign works for private clients, yet fits seamlessly into other design teams and companies to provide everything from ideas to construction of 3D computer models for tooling and production. www.mwdesign.co.nz
Bunce Motor Company specializes in the importation and selling of Chevrolet/GMC vehicles and spare parts from North America, converting these vehicles to right hand drive for the New Zealand and Australian markets, the manufacture of right hand drive components, and vehicle sales and service. www.bunce.co.nz
Case Study: Polhemus FastSCAN used in The Lord of the Rings Motion Picture
The Lord of the Rings used a template for all of their computer generated characters from detailed clay maquettes sculptured by workshop artists. The Polhemus FastSCAN, 3D scanner became invaluable in capturing data off the scale creature maquettes.
In a traditional approach, the digital modelers would have modeled the creature by eye, referencing the sculpture, or loaded photographs of the maquette into the computer, resulting in rough CG approximation of the detailed maquette.
At the start of The Lord of the Rings, Weta Digital became involved with Applied Research Associates, a New Zealand company that had developed a groundbreaking 3D scanner, later picked up in the United States by Polhemus and marketed as FastSCAN. That 3D scanner became invaluable in capturing data off the scale creature maquettes.
"It was not only incredibly accurate; it was free-form. It was free to rotate at any angle in relation to the object being scanned, so there weren't areas in shadow to the scanner. The wand could get into every nook and cranny." Matt Aitken
"The scanner was extremely successful in capturing minute detail," creature creator, Richard Taylor, elaborated. "To facilitate this high-end scanning, we created very large-scale scannable maquettes for some of the creatures, up to six-feet tall, in some cases."
"As the scan progressed, we could see the creature growing in real time in the computer. One of the problems with visual effects is it's too easy to alter the designs. With this technology, we could tightly control the art direction..." said Taylor.
In the course of several passes, the scanning laser would be moved over every surface of the maquette.
The software attendant to the scanner would then stitch those passes together, creating a single surface with no overlapping data due to its ability to recognize when the laser was passing over a point already scanned. What resulted from the scan was a highly detailed, single polygonal mesh model (see image).
First image courtesy of ARANZ; Second image courtesy of Cinefex
Extracted with permission from "Ring Masters", by Jody Duncan.
Cinefex #89 - January 2002 - pp 64-131.
Copyright © 2002 by Don Shay. www.cinefex.com
Third image courtesy of Weta Digital - New Line Cinema all rights reserved
Case Study: Polhemus 3D Scanner Used In Movie Character Animation
As the industry's most compact handheld laser scanner, FastSCAN™, is a fast, flexible and attractively priced system for scanning 3D objects and significantly speeds up the 3D modeling and animation process. FastSCAN was the perfect solution for creating special effects for this movie project.
First Sun is a company associated with The Gibson Group, dedicated exclusively to feature film production. In 2000, it premiered writer/director, Glenn Standring's The Irrefutable Truth About Demons, at the Cannes Film Festival.
The Gibson Group is recognized as one of New Zealand's leading independent film and television production companies. It has built an international reputation based on creativity and professional excellence and specializes in the production of high-end television drama for both primetime and children's audiences. Arts magazine, comedy and information programming also contribute to an output of between 80 and 100 hours of programming each year.
Nigel Streeter, who was the Special Effects Supervisor for Demons, designed and set up the Gibson Group CGI facility three years ago. He has remained at the helm ever since, producing a steady stream of impressive visual effects. As well as creating visual effects, Nigel and his team are skilled at 2D and 3D animation, specifically the creation of 3D environments and 3D character animation. They also write their own CGI scripts, and develop software for specific graphic requirements.
The challenge for Nigel and his team when working on Demons was the daunting task of developing special effects on a budget that was considered very limited, based on the effects they planned to create.The Polhemus 3D FastSCAN was the perfect solution.
As the industry's most compact handheld laser scanner, FastSCAN™ is a fast, flexible and attractively priced system for scanning 3D objects and significantly speeds up the 3D modeling and animation processes. Instead of bringing objects to the scanner, users take FastSCAN directly to the object – anywhere in the world.
Built with Polhemus' world-renowned FASTRAK® tracking technology, FastSCAN combines handheld convenience with the ability to "auto stitch" 3D models together in real-time. The scanner knows at all times exactly where it is in relationship to the object that it is being scanned.
This information is transmitted to the imaging software that instantly joins the pieces into a single, exact three-dimensional replica of the object being scanned. When you're done scanning, the files can be easily exported into nearly all leading CAD, graphics, and animation applications.
To keep production of Demons on schedule, a quick digital solution was needed. After an intense review of digital technology options, they came upon FastSCAN. First Sun determined that FastSCAN was the only viable scanning solution, and decided to go for it.
"The scanner arrived Friday evening and we began scanning within 30 minutes of unpacking the unit. We were extremely surprised with how easy the scanner was to use, and how portable it was." Nigel Streeter
The Producers immediately became at ease with their decision to go digital as they saw how simple it was going to be, and how much more detail and realism they could achieve by using FastSCAN. First, Nigel and his team digitized a small scale Maquette of the whole creature, then the full-scale model of the head and shoulders (bust). See the screen print of the scan that was digitized with FastSCAN and the maquette of the demon. This was created in just 15 minutes.
The scan of the head was used to get the detail of the creature. The scan of the small Maquette was used for the body, which was matched up to the head, scans in the digital domain. The scans were exported as obj.wire frames, and imported into Maya for manipulation, which was limited, as the scans were so clean and accurate.
"The high level of textural detail that we were able to capture was beyond what we ever imagined possible. It provided us with the ability to create creatures that lookvery real," said Streeter. "In the end, the FastSCAN allowed the movie to be truer to the original concept without filming the creatures in the physical world. FastSCAN also enabled the producers to view the special effects on screen in seconds. This helped to eliminate errors and made the entire creative processes more efficient."
The Gibson Group not only recognizes a need for the scanner as they utilized it here, but they would also like to have FastSCAN on every set to scan images that can be imposed into the film during post-production. According to Streeter, "We feel that FastSCAN is a great tool and reasonably priced solution. We would like to continue to use FastSCAN to produce high-quality, innovative, special effects for future projects. Scanning as a means of creating digital images, provides us with a fantastic solution for creating lower cost effects without having to sacrifice quality."
Quantification of Visual Interests
Multiple Object Tracking
Case Study: Polhemus 3D Laser Scanner Enables Perfect Prosthetic Fit
Hanger needed an alternative to the traditional plaster casting. Hanger and Polhemus teamed up to develop a 3D laser-scanning technology that would provide a faster, cleaner and less invasive alternative to traditional casting. The solution was FastSCAN.
Headquartered in Bethesda, Maryland, Hanger Prosthetics & Orthotics, a division of Hanger Orthopedic Group, Inc (NYSE:HGR), owns and operates over 600 orthotic and prosthetic (O&P) patient care centers nationwide. Staffed by nearly 900 certified practitioners, Hanger Prosthetics & Orthotics provides patients with convenient, consistent, high-quality care.
In the orthotics business, Hanger designs, fabricates, fits and maintains standard and custom-made braces that provide external support to patients suffering from musculoskeletal disorders and injuries from sports or other activities. In the prosthetics business, Hanger does the same for custom-made artificial limbs for patients who are without limbs as a result of traumatic injuries, vascular diseases, diabetes, cancer, or congenital disorders.
Hanger fits many proprietary technologies such as its patented ComfortFlex™ Socket, which combines science, technology, and anatomy to provide an intimate interface between the patient's body and the prosthetic device. Hanger's specialized patient care programs include International Upper Extremity and Lower Extremity Prosthetics, National Orthotics, Immediate Post-Operative Prosthetics (IPOP), and Diabetic Foot Management.
Plaster casting is the traditional method of fitting custom orthotics and prosthetics. This procedure can be messy, time consuming, bothersome, and may also cause trauma associated with manipulating post-surgical spinal patients.
The fitting of devices on children, who can be afraid of the casting and cast removal procedures, is often stressful for both the patient and parents. For example, the cranial casting procedure, used in the creation of cranial helmets, requires the infant's head be wrapped in wet plaster, causing an irritating experience for infants and parents.
A Better Solution
To enhance the overall patient treatment experience and ensure accurate orthotic and prosthetic devices, Hanger needed an alternative to the traditional plaster casting. Hanger and Polhemus teamed up to develop a 3D laser-scanning technology that would provide a faster, cleaner and less invasive alternative to traditional casting.
The three-dimensional laser scanner, developed by Polhemus and Applied Research Associates of New Zealand, exclusively for use by Hanger practitioners, named Insignia™, incorporates the same patented technology used by the United States Armed Services, which enables image capture of limbs, head or torso to occur in a rapid and accurate fashion for all patients in a variety of settings.
Insignia's compact, portable laser scanner works by casting a fan of laser light over the person's limb, head, or body, while the camera on the wand views the laser to record a cross-sectional profile of the object. To allow for patient movement during scanning, Insignia employs two embedded motion-tracking devices.
The practitioner attaches a small receiver to the patient, close to the area being scanned. This receiver works with the embedded motion-tracking device to determine the position and orientation of the scanner's wand, relative to the body part being scanned.
Using the Insignia scanning wand, the practitioner scans the part of the body being fit for a device. This is done by smoothly sweeping the handheld laser scanning wand over the body part, in a manner similar to spray painting, enabling the computer to reconstruct the full three-dimensional surface of the object within Hanger's proprietary CAD/CAM software.
Developed exclusively for Hanger, Insignia revolutionizes the process of fitting a patient for a prosthetic or orthotic device. Insignia's cutting edge technology, combined with Hanger's highly-skilled staff provides patients with highly accurate, well fitting devices, as well as significant improvements in comfort, convenience, and timesavings.
Patients no longer have to endure the mess and bother associated with plaster casting. "Insignia is a big improvement over plaster casting. There is less mess and it's so fast and easy. Insignia is a wonderful method for making a prosthesis," says Gayle Dekker, a Hanger patient.
For post-surgery patients, the Insignia scan requires little, if any, physical contact, and scanning can be performed on patients in bed. A unique symmetry feature used for post-surgical spinal patients allows the patient to be fit for a spinal jacket while lying in bed without having to roll from front to back. The Hanger practitioner scans one hemisphere of the body and the symmetry function built into the Insignia software creates the image of the opposite side to form a complete image.
This cutting edge technology ensures consistently accurate custom fitted devices. "My socket had a better fit than what I had before, especially around the knee," says Ken Hammer, a Hanger patient.
The scans are accurate to within one millimeter and the three-dimensional feature gives detailed surface information often lost with a cast or mechanical digitizer.
Insignia's proprietary CAD software creates a permanent patient record that allows for rapid refitting and adjustments, the justification of medical necessity for a new device, and better patient/physician information exchange.
The components of Insignia required to capture the patient's image – the laser wand, laptop, and motion-tracking devices – all fit into a compact, portable case that is smaller than a standard carry-on piece of luggage.
Conveniently, patients who cannot travel to a Hanger patient care center can be scanned at home, in the hospital, or in a nursing home/rehabilitation facility.
Created to design an array of prosthetic and orthotic devices, Insignia is currently being used by Hanger practitioners for the following devices:
- Post-op, preparatory, temporary and permanent protheses for foot, below-knee and above-knee amputees
- Functional and passive protheses for hand, below-elbow, and above-elbow amputees
- Ankle foot orthoses, spinal jackets and cranial helmets
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- Contact firstname.lastname@example.org for more information.
- For more information on Hanger, please call 1-877-4HANGER or visit: www.hanger.com
Case Study: Polhemus FastSCAN Digitizes World Renowned Sculptures
Renowned artists determined a way to decrease the creation time of sculptures, utilizing FastSCAN 3D laser scanner.
Ralph Helmick and Stuart Schechter are sculptors with a shared interest in the mechanics of visual perception. In 1994, Helmick and Schechter incorporated and opened Helmick + Schechter Sculpture (H+S) in Newton, Massachusetts. As highly respected artists, they are known for their massive hand sculpted collages located in malls, sports facilities, and businesses throughout the country.
Each collage contains numerous smaller carved objects used to form a larger sculpted figure. Since the artists began collaboration of their work, they have developed a range of experimental approaches linked more by underlying esthetic principals than a signature style.
The Handheld 3D Digital Scanning Solution
As H+S gained recognition, it became apparent they needed to reduce the amount of time it took to create each sculpture. Using traditional creative processes involve making molds of subjects by hand and casting them in a malleable material. Once the object is cast and then dried, the artists begin sculpting. After the artists sculpt the objects, they create a second mold and cast that is used to build the final sculpture. This process is very time consuming, especially when used to create a sculpture made up of multiple objects.
H+S determined that reducing the rapid prototyping process was the most efficient way to decrease time spent to make each sculpture. This would allow them to accommodate the number of projects they were being commissioned to sculpt. However, H+S also needed to find a solution that did not compromise their artistic integrity.
After extensive research into digitizing products, H+S determined they could hasten the mold making process to accomplish their goal. A faster mold making process would involve digitizing their subjects with some type of scanner. They found various 3D digitizing systems in the marketplace but quickly learned that most of the scanners were expensive and cumbersome. In addition, many of the larger stationary scanners required the use of a turnstile, which limited the size of the objects that could be scanned. Turntable units were also not practical.
H+S eventually dismissed these competitive products, and ultimately selected the Polhemus FastSCAN, a lightweight, reasonably priced and portable handheld 3D-laser scanner. "We couldn't use a scanner with a tabletop turntable because it limited the objects that we could scan. We needed a scanner that was portable and could scan the surface area of both large and small objects," Helmick said. "FastSCAN allowed us to quickly and easily scan objects on location or in our studio with a high degree of accuracy."
What set the Polhemus scanner apart was its ability to scan objects and provide a full 360 degree digital representation of the surface area with sufficient detail.
Schechter commented, "FastSCAN can export the data representation of the scan in almost any file format." Schechter continued, "The ability for us to bring FastSCAN on location was also a big plus. FastSCAN can be hand carried virtually anywhere, and can scan objects of all sizes in minutes."
Using the Polhemus Solution
With the Polhemus FastSCAN, the artists are able to quickly create realistic and accurate digital representations of the objects that they sculpt. Schechter noted, "The key to this modern technique of digitizing our subjects is its ability to capture enough detail that we take and enhance, giving each object our own sculpted signature; this can't be achieved with computer generated art." Helmick continued, "This allows us to add our artistic vision and distills the important elements that only come from the eye and hand of an artist."
"Using digital scanning has tremendously simplified our creative process. Before FastSCAN we had to manually form each mold, which is a long and tedious process. Now we have the initial casting in our hands in a matter of days. The old method took weeks for the mold to be created and cast." Stuart Schechter.
With FastSCAN, H&S is able to create sculptures much faster by significantly speeding up the rapid prototyping process. It also has enabled them to use modern technology which shortens the creative process without compromising H+S's style and vision. According to Helmick, "Computer generated artwork does not allow an artist to put their true artistic signature on it. However, with FastSCAN we can create digital art that we handcraft. This is what makes our artwork so unique: it has a modern, yet hand sculpted look to it."
"The FastSCAN is a vital tool for us. It has allowed us to create many more sculptures than ever before, enabling us to significantly grow our business in a short period of time," said Schechter. "We also have been very pleased with the level of technical support Polhemus has provided. They have kept in touch, showing continued interest in our business and the performance of FastSCAN." Schechter continued, "Polhemus is good at sharing new technologies and product upgrades that we will continue to utilize."
Case Study: FastSCAN Cobra Takes Breedlove Guitars into the 21st Century
Breedlove Guitars, was outsourcing the reverse engineering and measuring of their guitars from Oregon to Montana, where they would use a CAD system. The FastSCAN Cobra made it possible for them to become more efficient in their production of acoustic guitars, by making tasks that once took days to complete take only minutes.
For years, Breedlove Guitars, based in Tumalo, Oregon, was outsourcing the reverse engineering and measuring of their guitars from Oregon to Montana, where they would use a CAD system to gather all the measurements needed to cut the wood and shape the guitars. This process would take several days or often more than a week, which drastically slowed down productivity and, to an extent, held back their business. What Breedlove needed was to find a way to do all of this at their own facilities in a more efficient and effective manner.
How Breedlove Solved Their Problem
Breedlove contacted a company in Auburn, Washington, called MultiCam Northwest. Through MultiCam, Breedlove was able to obtain "cut and carve" equipment, as well as a Polhemus FastSCAN Cobra. With all these advances, Breedlove was now able to do all of the preparation work at their own facilities in Oregon. The FastSCAN Cobra made it possible for Breedlove to become more efficient in their production of acoustic guitars, by making tasks that once took days to complete take only minutes now.
To get all the information needed to create the guitars, through reverse engineering, the guitar first needed to be scanned, which only takes a few minutes. After the guitar was scanned and put into a mesh format for measurements, the scanned file was saved as an STL file. Once saved as an STL file, Breedlove then can export the file into a CAD program known as Rhinoceros, a modeling tool for designers that utilizes Windows technology. The scanned image is processed through the CAD system, and put into a program called MasterCam, developed by MultiCam Northwest. This program is loaded onto the Multi-Cut & Carve machine, making it possible for the equipment to cut the wood into a perfect shape for the guitar.
By eliminating the outsourcing of the reverse engineering for their guitars, Breedlove was able to produce a finished product in much less time. Their productivity increased dramatically, as well as their profitability. The FastSCAN Cobra, combined with the MultiCam system, was a great decision and a change in the right direction for Breedlove. (Image shows a detailed scanned picture of the guitar neck, put into mesh form for detailed measurements).
The MultiCam "Cut & Carve" Solution
MultiCam, LP is the leading manufacturer of CNC routers. Thousands of machines are installed worldwide. Twelve MultiCam Technology Centers are located throughout the United States to provide local support, repair service, sales and application training. The MultiCam is a proven solid production system and organizations from a wide variety of industries find it to be a trustworthy and reliable routing solution. The rigid, all steel construction of the MultiCam makes it a robust platform for high-speed cutting and exceptional edge quality.
3D CAD Case Study: Modeling 3D Data in SolidWorks
Tru-Test Ltd is a multinational company that designs, develops, manufactures and markets agritech and electrophysiological solutions. Tru-Test required 3D data of peri-natal infants to aid in the design of a specific electrode array for premature infants, to be used with a new type of EEG monitoring device.
This required Tru-Test to use a computer model in order to determine the size and geometry of the electrode to fit the shape and curvature of the heads. The need for accurate data was paramount. However, suitable 3D data was not available.
The solution was found with the Polhemus FastSCAN™, a handheld 3D laser scanner, which was used for scanning two anatomically correct, premature baby dolls. FastSCAN's FastRBF Extensions™, was used to create a model for exporting to SolidWorks.
Scanning and Processing
The head and shoulder areas of the two dolls were scanned using the FastSCAN (Figures 2a and 3a). The FastRBF Extentions automatically fits a surface to the original data points to guarantee that the output mesh is free from holes and watertight (Figures 2b and 3b). The FastRBF surface is also guaranteed to pass within a specified tolerance (in this case 0.1mm) of the original surface points. Furthermore, it has smoothing capabilities that can remove noise from the data. This proved invaluable when scanning the fetal doll.
The doll's surface was a semi-opaque silicon rubber (Figure 1), that gave a very poorly defined (noisy) surface as viewed by the laser scanner (Figure 2a). Powdering or painting the surface would have solved the problem, but it became apparent during processing with the FastRBF Extensions that this was not required. The smoothing feature ensured that the noise was removed but the detail of the original surface was retained (Figure 2b).
As a CAD package, in this case SolidWorks, was the target program for the output model, it was important to reduce the facet count to a manageable size. The FastRBF Extensions simplification reduced the polygon count for the fetal doll from approximately 169,000 facets to 23,000 facets (a reduction of 86%), and for the newborn doll, from approximately 97,000 to 17,000 (a reduction of 82%).
A close-up of one of the dolls before and after simplification is shown in Figure 4. To achieve this, an accuracy parameter of 0.05mm was used, so that the simplified mesh would be no further than 0.05mm from the non-simplified surface.
(a): The fetal doll: raw data comprising approximately 141,000 facets
(b): The FastRBF processed surface comprising approximately 97,000 facets
(a): The newborn doll: raw data comprising approximately 247,000 facets
(b): The FastRBF processed surface comprising approximately 169,000 facets
Figure 4: The newborn doll before and after FastRBF simplification: the fine mesh and the simplified mesh
Figure 5 shows the closed surface which was then exported as IGES 128 (NURBs) entities, which is one of the many industry standard formats that FastSCAN supports.
In order to compare the ability of SolidWorks to import these surfaces, the fetal doll model was exported as a closed surface, i.e. with closed planes at the bounding box (Figure 5), and the newborn doll was exported as an open surface, ie the model was not closed at the shoulders and base.
Importing into SolidWorks
A product engineer from Tru-Test was given the task of importing and manipulating the objects in SolidWorks. For the (closed) fetal model, importing took approximately three minutes, resulting in an "imported solid" (as seen in the feature manager tree). The product engineer was able to start working on the model immediately.
With the open newborn model, the task of creating a solid model involved a few more steps before SolidWorks would recognize the model as a solid. Briefly, these included:
- Lofting surfaces over the open boundaries using the "create planar surface" command
- Saving the model as a Parasolid file, and reloading the file
- Using "import diagnosis" on all the surfaces, and choosing the "close all gaps" option
- Again, saving the model as a Parasolid file, and reloading the file – which was now a perfect SolidWorks imported solid model
The resulting models as exported into SolidWorks are shown in Figure 6.
Figure 6: Screen captures of the two models in SolidWorks
According to the Product Engineer, with the help of FastSCAN, "The project was very satisfying and very successful."
The mathematical consistency of the post-processed data guaranteed by the FastSCAN FastRBF Extensions was critical in creating models that could be loaded and manipulated in SolidWorks. The following table summarizes the steps involved (times for the fetal model).
CAD Modeling by Product Engineer and Mechanical Draughtsman with the Research and Development team of Tru-Test Ltd
Case Study: Polhemus Technology Used in New Zealand Fisheries Research
The National Institute of Water and Atmospheric Research (NIWA), in New Zealand, carries out fish biomass surveys for the Ministry of Fisheries using acoustic techniques. This involves surveying areas of the ocean with an echosounder that sends out pulses of sound. Echoes are received back from schools of fish and these are recorded for later analysis. Polhemus FastSCAN 3D laser technology was utilized in this research study.
Echoes From Fish
Using lasers to study how much sound reflects off a fish, a new method of recording three-dimensional shapes is being applied in research aimed at improving assessments of New Zealand's fisheries resources.
The National Institute of Water and Atmospheric Research (NIWA), in New Zealand, carries out fish biomass surveys for the Ministry of Fisheries using acoustic techniques. This involves surveying areas of the ocean with an echosounder that sends out pulses of sound.
Echoes are received back from schools of fish and these are recorded for later analysis. The total strength of the echo from a school is divided by the strength of an echo from an "average" fish to estimate the number of fish present. Therefore we need to know how much sound is reflected from various species of fish – known as their target strength – and how this varies with fish size and orientation. For further details on how fish biomass is calculated using acoustic surveys, see Water & Atmosphere 4(1): 13-17.
This article describes the swimbladder modelling technique for estimating the target strength of fish.
Fish and Their Swimbladders
Many fish have a gas-filled swimbladder used for buoyancy control, for sound production, and as an aid to hearing. Sound reflects particularly well at abrupt changes in density and sound speed, such as between fish tissues and the gas in the swimbladder.
The swimbladder typically generates about 95% of the sound reflected from fish. The remainder comes from the flesh, bones and organs. Hence, acoustic models of the sound reflection from swimbladders are an appropriate way of estimating the target strength of some fish. These models are particularly useful for species where it is difficult to collect data in their natural environment (termed in situ data).
As an example, the results of orange roughy acoustic surveys conducted in 1998 and 1999 suggested that more than 50% of the orange roughy biomass was to be found on, or just above, flat seafloor outside the main spawning concentrations or away from the main spawning hills. One of the primary uncertainties in the estimates of orange roughy biomass on these flat areas is the target strength of other species found mixed with the orange roughy. The target strength of these species is unknown or poorly known, reducing the accuracy of the orange roughy biomass estimates.
Modelling the Swimbladder
Swimbladders often have complex shapes with many ridges and hollows, which makes them difficult to measure. Because we cannot derive exact mathematical equations for the target strength of these swimbladders, we use a technique that divides the surface into many small regions and then sums the contributions from each region using a formula called the Kirchhoff integral. This produces an estimate of the scattering from the whole swimbladder.
But how can we map the three-dimensional (3D) surface of the swimbladder?
First we take a freshly caught dead fish and inject resin into its swimbladder. Knowing how much resin to inject is a bit subjective, and as a rule we use a volume of resin equivalent to the volume of gas required to keep the fish neutrally buoyant. (This is obtained by weighing the fish in air and then in seawater – the difference is the amount of positive or negative buoyancy of the fish). The resin is left to set, after which the resin cast is removed from the fish and cleaned. This gives us a reasonably accurate cast of the swimbladder, and the procedure is sufficiently easy that we have collected, to date, over 400 casts from 28 species of fish.
In the past we obtained a 3D representation of each cast surface by first slicing it every 1 to 10 mm, depending on the smoothness of the cast shape. The swimbladder shown in the illustrations would have been cut into about 150 slices. Each two-dimensional slice was then digitised, and finally the 3D shape reconstructed using a computer program. This process was very laborious, prone to errors, time-consuming (several hours to several days per cast) and it destroyed the cast.
To improve upon this, we have started using a new method. A handheld 3D laser scanner is used to scan in the cast quickly and easily – the time taken is now a few minutes, and the cast is left intact. The photograph shows one of the authors scanning a swimbladder cast from a hake (Merluccius australis), and the figure above shows the resulting 3D image.
The FastSCAN scanner has considerably improved the quality of the 3D data and has also allowed us to scan several hundred casts very efficiently.
In the ocean, fish swim at various tilt and roll angles, and this needs to be taken into account. So our next step is to calculate the target strength of the digitised swimbladder casts at various orientations. Also, the casts are scaled to simulate fish of different sizes and the target strength calculated. The results from swimbladders of different-sized fish for each species are used to estimate a general relationship between fish length and target strength for each species.
Interpreting the Results
The relation between target strength, fish size and tilt for a hake swimbladder is shown in the graph.
The general form of the relationship is common to many species. As the swimbladder tilts, the effective size of the swimbladder decreases as viewed from the direction that the acoustic wave is travelling and, because a smaller object reflects less sound, the target strength decreases. The pronounced low values in the curve occur at angles where sound scattered from one part of the swimbladder cancels out sound scattered from another part of the swimbladder. For low values of fish length/acoustic wavelength (L/l), the variation of target strength with tilt angle is relatively smooth and gradual. As the fish gets larger (or the acoustic wavelength decreases – which is the same as increasing the frequency), the variation in target strength with tilt angle becomes more rapid and contains more very low values.
Modelling has given us target strength estimates for some species for the first time, leading to improved acoustic biomass estimates. Further research is planned that will use the 3-D swimbladder models to investigate ways to identify the species of the fish using just the acoustic echo.
Animation Case Study: Formthotic Advertising
Foot Science International commissioned Montage Multi Media ("Montage") to produce a thirty second looping animation showing the relationship between the human foot and their Formthotic innersole. The Polhemus FastSCAN 3D laser scanner was used.
The project required a high degree of anatomical accuracy and would have been a very laborious modeling exercise had it not been for the handheld laser scanner.
Although the scanner had some trouble in the crevices of the toe area, it produced a level of detail throughout the rest of the foot that was simply amazing. Veins, tendons and bones all came through extremely well. The image reflects the scan of the foot.
The scan had around 52000 polys (this was reduced from the much higher resolution original scan), but this was still too large for Montage's needs and a little unwieldy for additional modeling. Montage used polygon reduction software to take the polys down to around 15000
Using the scan as a guide, a set of new toes was generated for the foot using Lightwave's MetaNurbs feature. After removing the toes from the scan, a bridge was then made between the new toes and the rest of the foot using the Skin command.
The scanner gave Montage an excellent representation of one of a staff member's feet in a scan that took only seconds. The setup time and experimentation was minimal.
Despite initial concerns about the modeling, texturing was easily the most time-consuming part of the project, requiring maps on all three axes, seamlessly blended together.
The final animation was well received by the client and was used as part of an interactive kiosk at an international tradeshow in Germany and also featured in a TV commercial.
The image represents a frame from the 30-second animation.
Modeling, animation and text by Peter Wain of Montage Multi Media, Christchurch, New Zealand; find out more at: www.montage.co.nz.
3D Case Study: The Virtual Frigate
Using the Polhemus FastSCAN, a 1.2 meter model of Te Kaha, a frigate in the Royal New Zealand Navy, was able to be digitized.
To accomplish this, cross sections of the hull were sliced from the digitized object files. The deck, guns, radar, etc, were then added by hand, using the digitized object files for obtaining scale reference points.
Finally, image files were rendered, and a Java applet was written to provide the interactivity, to form the final 3D models that appears on the Royal New Zealand Navy website.
Exploded view with final 3D model (inset)
Modeling, animation and text by Craig Pownall of Zivo (formerly Clearview), an internet integration and website development company.
Case Study: G4 Used in Virtusphere Locomotion System
Polhemus G4™ wireless motion tracker used with Virtusphere, the 10-foot hollow sphere that allows a total immersion experience. G4 delivers both position and orientation, as users navigate various scenes and terrain wearing a head mounted display.
Imagine stepping into what looks like a human-sized gerbil wheel, and being completely immersed in a virtual reality world that’s enveloped by a sphere—a sphere that transforms your entire environment at the click of a button. With endless possible scenes to explore, you could be taken on a strenuous trail run that pushes your limits, tour the city sites of Moscow, or even test your reflexes in a combat zone where every second counts.
These scenarios are all made possible by Virtusphere, the virtual reality locomotion simulator. Virtusphere utilizes the Polhemus G4™ 6DOF wireless motion tracker, based on its portability, seamless tracking capabilities, and the fact that it delivers both position and orientation.
(Image shows Polhemus 6DOF Sensor attached to HMD)
The Latypov brothers are the brain power behind Virtusphere. Ray Latypov, Virtusphere CEO, and Allan Latypov, CTO, developed the idea and perfected the Virtusphere product. It works similar to a giant version of a track ball on a computer mouse. The 10-foot hollow sphere is mounted on a special platform that allows the user to rotate freely in 360 degrees. Users wear a head-mounted display, and the sphere design allows them to walk, jump or run, as they are fully immersed into a virtual environment.The wireless G4 provides the user complete freedom of movement as they react to the changing scenes viewed on the head-mounted display.
Paired with the G4 Polhemus technology, the user is untethered, unrestricted, and every movement is in sync with their virtual environment.
The sphere is portable, weighing approximately 650 pounds and requires about 100 square feet to set up the apparatus. The sphere can be transported by minivan or a vehicle of similar size, and takes approximately six hours to construct.
Powered by Polhemus
Polhemus provides the motion tracking technology for the sphere application. The highly accurate tracking capabilities of G4 make it possible for users to react in real-time to real-world obstacles as they walk, run and jump.
This level of 6DOF precision tracking, combined with the locomotion of the sphere, provides the user with the most realistic training simulation experience possible. This makes Virtusphere ideal for applications such as individual training, team training, and mission rehearsal exercises. (Image shows Polhemus 6DOF Sensor attached to gun manipulator).
Virtusphere is committed to providing solutions to end users, application developers and integrators. An endless possibility of applications exists,by using all of the same hardware and simply changing the software. Aside from virtual military combat training for soldiers, Virtusphere can also be helpful in training security forces, fire safety personnel, or other types of teams that can benefit from muscle memory training or reflex testing. Outside of training exercises, other applications for Virtusphere include: virtual tours offered in museums, virtual workouts in fitness centers, virtual architectural walk-throughs, and innovative gaming applications that allow the users to be immersed inside their own video game.
Latypov favors the Polhemus G4 tracking solution because he says, “Like Virtusphere, the Polhemus G4 tracker is the closest thing to the natural environment.”
The Future of Virtusphere
When asked what the future holds for Virtusphere, Ray Latypov says, for him, seeing his idea come to life is already magic, but he is still shooting for the stars, and has several other new ideas in the works. He refers to himself as an inventor, and a scientist—and some see him as a visionary. As far as what’s next for Virtusphere, Latypov replied in true visionary fashion, “I think about all the things you could do…and I say…why not?”
The Russian born Latypov brothers had an interest in computer video games and saw potential for something new. Ray Latypov was educated in physics, and had a background and interest in mathematical modeling and simulation.
In 1993, Ray Latypov went to the New York City library and devoted a month to reading about virtual reality. He was surprised to learn that although other systems existed, none utilized immersive locomotion. Latypov formulated a clear vision to develop a virtual reality locomotion solution. He began to think of all the ways it could be used, including military training for dismounted users. Latypov says, “Pilots have this type of training available to them; why send soldiers to war into dangerous situations without the most realistic training environment, instead of using one that actually involves training muscle memory? Virtusphere delivers this.
Virtusphere has gained much media attention and has appeared on CNN, Fox News, and the Discovery Channel, among other media outlets. The Virtusphere product has been utilized in a variety of ways—everything from entertainment for large corporate parties to training and simulation for military candidates.
Case Study: G4 Tracker - Seamless System Integration
The G4 motion tracker is getting rave reviews in terms of functionality--and has been described as best-in-class, based on performance alone. But it’s also getting a significant nod for its quick set up, user friendly design, and ease of system integration. Khymeia, a virtual reality rehabilitation company, located in Italy, uses the G4 tracking system for their virtual reality rehabilitation systems. Read why G4 was the perfect solution for Khymeia.
When it comes to selecting a motion tracking product, choosing the right kind of technology is critical, and dependent on the specific application. Evaluating the right product within that realm of technology is the next step. But significant consideration should be given regarding the complexity of the system set up and the integration process.
Roberto Furlan, Managing Director from Khymeia Group, reported that upon receiving the latest wireless motion tracker, G4, a seamless implementation was achieved and the product was easier to use than any similar product he had tried before.According to Furlan, G4 exhibited superior qualities compared to other trackers. The product was a perfect fit for their virtual rehabilitation application.
"Total implementation of the G4 system required less than two working days--and it works great with our software." In the world of software integration, this is considered an extremely fast integration phase.
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- Visit the Khymeia Website
- Read More About G4--The Latest Wireless Polhemus Motion Tracker
- For more information contact: email@example.com
Case Study: G4 Wireless Tracker Reported to Have Seamless System Integration
When it comes to selecting a motion tracking product, choosing the right kind of technology is critical, and dependent on the specific application. Evaluating the right product within that realm of technology is the next step. But significant consideration should be given regarding the complexity of the system set up and the integration process.
With the recent release of the latest 6DOF (Degrees of Freedom) Wireless Motion Tracker from Polhemus, G4 is getting rave reviews in terms of functionality--and has been described as best-in-class, based on performance alone. But it's getting a significant nod for its quick set-up, user friendly design, and ease of system integration.
Roberto Furlan, Managing Director from Khymeia Group, a virtual rehabiliation company, reported that upon receiving the latest wireless motion tracker, G4, a seamless implementation was achieved and the product was easier to use than any similar product he had tried before. According to Furlan, G4 exhibited superior qualities compared to other trackers, and he added, "Total implementation of the G4 system required less than two working days--and it works great with our software." In the world of software integration, this is considered an extremely fast integration phase.
Ease of implementation for G4 can be attributed to a few factors. Historically, much time and consideration has gone into the development of the SDK (Software Development Kit) for all Polhemus motion trackers, including flagship products, such as LIBERTY, PATRIOT, and FASTRAK. With each motion tracker that has been introduced, there is continuity with software design, and the same basic interface exists for all Polhemus trackers.
Users benefit from the knowledge that comes from over 40 years of industry experience in creating a user-friendly integration process. Polhemus is reputed to have an SDK that's very user-friendly and the G4 is consistent with this, providing the developer all the necessary tools, including clearly documented information and comprehensive code samples.
The manual that accompanies G4 serves as a thorough and detailed guide to refer to as the user is walked through the simple screen prompts. Also, because of the nature of Polhemus proprietary electromagnetic technology, installation does not require elaborate equipment and the actual set-up of G4 takes only minutes.
Current users of Polhemus motion trackers will appreciate that the SDK for G4 allows the user to migrate to G4 fairly easily. Great time and consideration went into the SDK, with the realization that some customers with current Polhemus systems would want to transition to G4 upon its release.
The SDK is full of great examples. It's well designed, so its very clear about what you need to do in your code," according to a Principal Software Engineer at Polhemus.
Khymeia Group is located in Padova, Italy, and has been a long-time partner with Polhemus as an OEM since 2001.They have strong industry knowledge and are well aware of competing technologies, as well as the value of seamless, timely system integration.
Furlan was enthusiastic, saying "G4 is really remarkable, in front of any other device that we experienced until now. It's really a great product that definitely surpasses all others in its class."
- Read more about: G4--The Latest Wireless Polhemus Motion Tracker
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- Contact firstname.lastname@example.org for product information.
Case Study: Polhemus Wireless Tracking Used For Augmented Reality
Total Immersion is an augmented reality (AR) solutions provider based in France. Committed to become the leader in augmented reality solutions, Total Immersion has invested in people and technology to provide the most powerful AR solution. Total Immersion chose LIBERTY™ LATUS™ from Polhemus to advance their AR solutions.
LIBERTY LATUS, a totally wireless motion tracking system, integrates easily with Total Immersion's D'FUSION software, which inserts virtual 3D objects into live video images. This solution provides the user with a non-invasive, interactive environment between the user and real time video capture.
Augmented reality is the use of live video imagery which is digitally processed and "augmented" by the addition of interactive 3D graphic objects. This is achieved by overlaying computer generated graphics, sounds and haptics into real world environments.
LIBERTY LATUS uses wireless markers to track position and orientation of an object. Each self-contained marker is tracked in space by receptors, each of which provide an eight-foot diameter spherical coverage. The system is capable of accommodating up to 12 markers and up to 16 receptors to create large areas of coverage.
Traditionally, special effects are created offline, frame-by-frame, requiring user interaction and computer graphics system rendering. Now with D'FUSION, the software analyzes the live action images to determine the camera parameters and uses this to drive the generation of the virtual graphic objects to be merged. The user holds a wireless tracking marker to specify where the 3D objects need to appear in real time.
The camera follows the movement of the hand and the result is displayed onto the television screen. Because the marker tracks position and orientation of the "virtual" object, which appears to be in the hand of the user, it can be simulated as if it were a real object.
The wireless technology is a significant enhancement to Total Immersion's AR solution, enabling the user to have complete freedom of movement without the concern of wires (see photo: Virtual 3D image of car prototype).
Total Immersion utilizes this advanced technology in various industries and has most recently been chosen by CBS News to enhance its show 48 Hours. Hosts of the show will use D'FUSION to provide viewers with technical and scientific explanations directly on the set.
An automobile manufacturer used this technology in a large corporate presentation where they introduced a prototype of a new car. Since the car only existed in virtual 3D form, this technology was extremely useful in providing a model of the prototype, including color options.
Other industries Total Immersion markets its AR solutions to include aerospace, theme parks/entertainment, special events, military, and architecture.
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Case Study: LIBERTY LATUS Used For Helicopter Trainer
Building on the success of United Kingdom-based Virtalis' Reality Helicopter Voice Marshalling Trainer, upgrades for which were delivered to the Royal Air Force (RAF) in 2007, the company has now developed a portable variant of the training system which features the Polhemus LIBERTY LATUS tracking system. The Helicopter Crew Reality System Portable trainer is aimed at helicopter rearcrew undertaking tasks such as operating with underslung loads, SAR and general operations in difficult terrain which require input from crew in the rear of the aircraft.
Andrew Connell, Virtalis Technical Director, explained that, "by using a low cost, standard PC, which works from a single graphics card, we have created an off the shelf product which takes only ten minutes to set up. We have been able to harness developments in computing power so it offers advances in graphics quality, performance and user interfaces. The rest of the system consists of a head-mounted display, a tracking system, two LCD panels and a joystick.
Like our RAF system, it features three marshalling environments: sea, land and coastline, though in recognition of the variety of helicopters in use around the world, it can feature different models. It is simple to customize, so that new local terrain can be easily generated. Tailored systems for different helicopters and/or familiar landscapes will cost a bit more than the standard model."
The skills performed by rear aircrew play a vital role in both search and rescue missions and in the delivery of military and survival resources to remote areas.
Located in the rear cabin of a helicopter, harnessed aircrew monitor the landscape through the open cabin door and verbally relay flight commands to the pilot in order to guarantee an accurate and safe approach to the helicopter's landing site or target object.
Two bases responsible for the helicopter training within the RAF, the Central Flying School (Helicopters) and Defence Helicopter Flying School at RAF Shawbury and the Search and Rescue Training Unit at RAF Valley are currently operating the original system.
Like its predecessor, the new system utilizes Virtalis' real-time rendering engine, kRender. This allows the student to see a seascape animated right to the horizon. Such details are important because aircrew are trained to use surface physical details to help gauge distance for the pilot.
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- For more information on the Reality Helicopter Voice Marshalling System, please contact Virtalis.
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- For more information contact: firstname.lastname@example.org
Case Study: Neuroscience Application Powered by Polhemus Trackers
Polhemus motion tracking technology enables motion measurement in a neuroscience application. Polhemus proprietary electromagnetic technology is ideal for this type of work because of its high level of accuracy and ability to produce repeatable results.
Imagine holding a cup of coffee, and just as you begin to take a sip, your hand begins to tremble uncontrollably. It’s this type of simple daily task that leaves Parkinson’s Disease patients feeling frustrated and asking for answers--from doctors and the research community.
At the Institute for Neural Computation in La Jolla, California, the approach is to analyze the normal motor control and learning processes, and the nature of the breakdown in those processes in patients with selective failure of specific sensory of motorsystems of the brain.
Working with the patients after the surgery enables Dr. Poizner to evaluate the effectiveness of Brain Stimulation Therapy. By using Polhemus precision motion tracking technology, Dr. Poizner is able to measure and evaluate how well the therapy is working.
By connecting the light-weight and unencumbering Polhemus sensors to the patient’s hand, for example, he is able to capture quantitative data and analyze the degree of trembling the patient experiences, down to the slightest of movements. Dr. Poizner then reports this quantitative data to the clinical side, providing critical insight into how well the therapy is working (image: courtesy of the Poizner Lab). Polhemus’ proprietary electromagnetic technology is ideal for this type of work because of its high level of accuracy and ability to produce repeatable results, said Dr. Poizner.
The Poizner Lab utilizes various Polhemus motion tracking products, including: FASTRAK®—used to digitize positions of EEG electrodes and LIBERTY™—both 8 and 16-sensor systems used for measuring patient reach and grasp, and other biomechanical metrics
“It was important that we accurately tracked in space without any line of sight occlusions. This is very high tech—as it measures the most subtle movement.”
Research in this area of neuroscience has been particularly challenging in the past. A method for capturing body movement three-dimensionally and correlating it with a patient’s brain wave activity will be a significant advancement in understanding therapeutic effectiveness.
According to Dr. Poizner, “The ultimate goal was to be able to quickly and cheaply provide an assessment in a quantitative, correlated, rigorous fashion.”
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Case Study: Motion Capture System for Hand Tracking Using Polhemus System
In this study, we developed the high accuracy Hand MoCap system by using the electromagnetic tracker LIBERTY™ 16 tracking system by Polhemus. The system uses small and light receivers. The cables of the receivers were replaced with special thin cables so as not to block the movement of the fingers.
Kazutaka Mitobe, Takaaki Kaiga, Takashi Yukawa,
Takeshi Miura, Hideo Tamamoto, Al Rodgers and Noboru Yoshimura
Akita University, Warabi-za Co., Akita Keizaihoka University, Polhemus
Motor area that controls the movements of the human body is divided functionally into each control region. In the motor area, the area of the hand is almost the same as the total area of arm, torso and lower body. This physiological fact indicates that human hand movements require very complicated control.
As a result, our hand can perform high precision movements as an actuator. Motion capture (MoCap) technique that can digitize a position and a posture as a time-series data is widely used in order to create animation and CG. It is very difficult to measure all hand movements because each hand has twenty-seven bones and nineteen joints. The most widely used tool for a hand MoCap has been CyberGlove (Immersion Co.) that can digitize only 80 percent of all hand movements. Therefore, it has been impossible to record the finger movements of a pianist that are high in speed and in accuracy.
In this study, we developed the high accuracy Hand MoCap system by using the electromagnetic tracker (LIBERTY™ 16 system, Polhemus) that used small and light receivers. The cables of the receivers were replaced with special thin cables so as not to block the movement of the fingers.
2. System Design
Figure 1 shows the composition of the MoCap system for a hand. The magnetic tracker that is composed from one transmitter (23*28*16 mm) and sixteen receivers (9.6*9.6*9.6 mm) can digitize the distance (x, y, z) from a transmitter to a receiver. The magnetic tracker can digitize the relative angle (Azimuth, Elevation, Roll) of receiver against a transmitter.
Each receiver was processed in order to fit to the finger. We used three receivers in order to measure one finger, and one receiver was used for the back of each hand. Sixteen receivers were used for each hand. Additionally, the adapter unit was modified with a stretch fabric band in order to fit any hand size. Each receiver was attached on the finger using Kinesiotex tape and liquid type plastic in order to prevent the receiver from sliding. Two LIBERTY systems were connected to a computer (ThinkPad, IBM) through a USB interface.
The hand MoCap can measure the data (six degree of freedom) of 32 receivers at the rate of 240Hz simultaneously. The spatial resolution of the hand MoCap was 0.0038 mm. The angle resolution of the hand MoCap was 0.0012deg.
The receivers were evaluated to test if the accuracy was affected by the proximity to one another. Our evaluation indicated that the accuracy was not affected even if each receiver was adjacent. The dispersion of position data was under 0.1mm, and the dispersion of angle was under 0.1 deg. This range of dispersion is sufficient to measure human finger movements.
In order to evaluate the user-friendliness of this system, we measured the movements of pianist's finger by the hand MoCap system. Musical composition was "Sonata KV 331, Turkish March" (Mozart, Wolfgang Amadeus). The hand MoCap data was converted into BVA format, and the data was read in MoCap software FiLMBOX. A skeleton and the model of a hand that had been made separately were read in FiLMBOX, and attached to the hand MoCap data that was read earlier.
Fig. 2 shows the CG animation of the pianist's musical performance scene (click the photo to watch Micro Sensor 1.8 in action!). We confirmed that the CG animation closely resembled the video image filmed by a video camera. This shows that the hand MoCap system can digitize the finger movements accurately. The automation of making the CG animation from the Hand MoCap data, which currently is done manually, would make a significant improvement. In the future study, we will develop the automatic algorithm in order to calibrate the hand MoCap data.
This study was supported by the 'strategic information and communications R&D promotion programme (SCOPE) of the Ministry of internal affairs and communications of Japan.
Case Study: Biomechanics Analysis—IST Integrates Polhemus LIBERTY
Innovative Sports Training (IST), based in Chicago, IL, provides complete solutions for 6 Degree-Of-Freedom (6DOF) motion capture and integrated comprehensive analysis. The MotionMonitor, IST's software package, integrated with Polhemus LIBERTY, the fastest, most accurate, scalable electromagnetic motion tracker available, creates the finest advanced data acquisition and analysis system in the market place. Combined, this provides a perfect set of tools for a quick and flexible setup, data collection and data analysis.
Once the LIBERTY is set-up, sensors (up to 16 available per LIBERTY system) are assigned to body segments. Various protocols can be used for tracking anatomical landmarks and defining local coordinate systems for each body segment. Once the subject/patient is setup, various user-defined parameters can be assigned to control the manner in which the activity is recorded, i.e. using event markers and triggers to start or end data collection such that all activities are synchronized to one specific event.
After data has been recorded, the activity along with graphical displays of data can be played back immediately. All standard kinematic and kinetic data can be selected from drop-down menu items. In addition, the user can calculate data with the user-defined data formula using any raw or processed data variable. Smoothing parameters such as a Butterworth filter can be applied uniquely to each sensor or data acquisition channel. Further enhanced functionalities for data reduction and exporting are also available.
Other hardware systems such as EMG, force plates, event markers, digital video, haptic devices, immersive displays and eye-tracking can be integrated as well for synchronous data collection and analysis along with the sensor data.
Why LIBERTY is the Professional's Choice
LIBERTY offers a quick and easy subject set-up and is a more economical system over traditional optical video systems. When line-of-sight could be an issue, the Polhemus LIBERTY system is a strong component to the solution.
LIBERTY is particularly valuable when time is of the essence, and researchers or clinicians need a system by which they can set-up their respective subjects or patients in minimal time. The LIBERTY system tracks all 6 degrees-of-freedom, which eliminates the set-up of multiple markers per body segment.
IST and Polhemus have built a strong relationship enabling the ability to provide a turn-key motion tracking solution to meet the various needs of many applications for data acquisition and analysis. For more information on IST, email firstname.lastname@example.org or visit www.innsport.com.
Case Study: US Olympic Gymnastics Study Using Polhemus Tracking Technology
The purpose of this study was to provide some preliminary information on the vault board. These initial results are part of a much larger ongoing study of the behaviors of gymnastics apparatuses. The Polhemus LIBERTY was used for the precision motion measurement that was necessary.
Wm A. Sands, Ph.D., Head – Sport Biomechanics and Engineering, U.S. Olympic Committee
Sarah L. Smith, Ph.D., Senior Biomechanist, U.S. Olympic Committee
Thomas Piacentini, Intern, Sport Biomechanics and Engineering
The vault board is used for vaulting take-offs, drills and skills for tumbling and vaulting, and other apparatus mounts. It has undergone a limited amount of scrutiny with regard to its behavior. However, the interaction of the vault board with gymnasts has scarcely been addressed. The following information is largely descriptive and meant to portray vault board movement behaviors during vaulting take-offs and our current preliminary efforts at studying the vault board.
Vault board behavior was analyzed by two primary means: high-speed video and magnetic motion tracking. Video analyses of vault board behavior were undertaken using high-speed video (NAC HSV 400) at 200 frames per second. Four reflective markers were placed on the board as shown in Figure 1. The reflective markers were video taped and then rendered to x-y coordinates (two-dimensional analyses) via Peak Performance Technologies software.
The raw data were analyzed for position, displacement, and velocity information. Figure 1 shows the vault board response that occurred when a young male gymnast performed a handspring vault over a vault table. Note that the response of the board indicated an intermediate recoil and a complex wave-like movement of the upper surface of the board that resulted in tipping of the board from side-to-side, as well as a whipping movement of the most forward board marker.
Figure 1: Note the white markers attached to the side edge of the vault board. These markers permit automatic digitizing of the vault board movements during a take-off impact. Note that the impact resulted in a side-to-side tipping of the vault board and a fore-aft complex wave-like motion. The graphic depictions below the photos show the traced movements of the four markers. The upper-left marker that corresponds to the top forward corner of the vault board shows an intermediate recoil. The 2D Raw Coordinates Spread Display plots each point while moving the image sequentially to the right to prevent marker positions from being drawn on top of each other. The Spread Display shows most clearly the intermediate recoil of the upper-left marker of the vault board.
In addition to the high-speed video of the vault board movement, later work has taken advantage of a magnetic motion tracking system. The LIBERTY™ magnetic motion tracking system was provided by Polhemus; the software was provided by Advanced Motion Measurement, LLC. Eight magnetic sensors were taped rigidly to the side edge of the top and bottom surfaces of the vault board.
These sensors provide six degrees of freedom sensing which means that the sensors are able to record positions in x, y, and z planes; the sensors also provide angular position and displacement information in a roll, pitch, and azmuth type format. These sensors provide sub-millimeter precision and sample at 240 Hz.
The precision was so great that the gymnast's last few running steps were detected by the sensors due to the deformation of the wooden gymnasium floor as the gymnast approached. Figure 2 shows the sensor configuration.
The magnetic motion tracking system is important due to the issue of the vault safety mat that will be used for Yurchenko-type vaults. Reflective video makers will be obscured by the safety mat making the detection of board motion impossible by traditional video means (Figure 3).
Figure 2: Magnetic sensors are shown taped to the side edge of a vault board's upper and lower surfaces. Note the transmitter for the magnetic sensors is shown on the tripod to the left of the vault board. The magnetic field created by the transmitter is sensed and the relative positions of the sensors are recorded by a laptop computer.
An example of the type of data provided by the magnetic sensors is shown in Figures 4 and 5.
Both figures show screen images of the Advanced Motion Measurement software with the sensor triads depicted along with a graph of the Z direction (up and down) sensor positions for six of the eight sensors. Figure 4 shows the results of a take-off on one type of vault board.
Figure 3: Image with gymnast shows the vault board is shown with the safety mat surrounding the board on three sides. An example of the type of data provided by the magnetic sensors is shown in Figures 4 and 5. Both figures show screen images of the Advanced Motion Measurement software with the sensor triads depicted along with a graph of the Z direction (up and down) sensor positions for six of the eight sensors. Figure 4 shows the results of a take-off on one type of vault board.
Figure 4: Sensor configuration and sensor movement are shown above. The graph shows the movement of sensors 1 through 6. Note that the take-off from this board presented an intermediate recoil that occurred during the initial descent of the magnetic sensors during the initial impact of the gymnast onto the vault board.
Figure 5 shows the movement of the sensors on a different type of vault board. Note that the take-off from this board does not show an intermediate recoil. Figures 4 and 5 were the result of the same athlete performing the same handspring vault. Sensor configuration and movements (see graph) are shown in the Figure 5 screenshot.
Figure 6 shows the vault board response for a Yurchenko vault. The Yurchenko vault take-off from the vault board is usually performed with a take-off impact much closer to the higher end of the board (i.e. closer to the vault table).
This type of take-off is performed after a round off which serves to turn the gymnast 180 degrees from his or her run; thus the athlete is facing backward when contacting the board.
Figure 6. Yurchenko take-off. Note that the vault board movements are more subtle and displacement patterns show that the gymnast's take-off has a more prolonged contact time with the board.
To conclude this initial discussion of vault board behavior, Figures 7 and 8 display the vault board recoil patterns as depicted by the sensors. Note that the recoil movements of the two measured vault boards are quite different for the same type of vault performed by the same gymnast. One of the boards (Figure 7) shows the sensors rising almost directly vertical. Figure 8 shows the sensors rising vertically initially and then move obliquely backward. At present, whether one movement is superior to the other is unknown.
Figure 7. Vertical recoil actions of one type of vault board. Note that the sensors rise almost directly vertical during recoil.
Figure 8: Note that the triads move vertically during the early phase of the major board recoil, but then the triads move rearward and upward during the latter phase of the recoil.
Figure 9 shows the displacement of sensors during a Yurchenko vault take-off in a multi-image format. Note that the forward-end (rightmost) of the board (Sensor 1) is deflecting the farthest and this corresponds to the take-off impact striking the forward end of the board.
This deflection pattern is in marked contrast to the typical type of impact pattern that is observed when gymnasts perform a handspring type vault where board contact occurs nearer the rear or leftmost part of the board (e.g., sensors 3 and 4).
Figure 9: Yurchenko vault, initial impact. Note that Sensor 1 is descending farther and more rapidly than the remaining sensors. This indicates the position of the feet where the gymnast contacted the board.
This preliminary report has shown that the two types of vault boards analyzed thus far behave differently. Moreover, it was shown that individual athletes often have markedly different impact signatures with regard to vault board movements.
In order to determine if these differences in both athlete and vault board behaviors are good or bad, further analyses will be necessary. Moreover, the results indicated that the board actions, gymnasts' impressions of these actions, and resulting take-off actions are often counter-intuitive and may defy conventional coaching wisdom. These analysis techniques will be applied to the floor exercise apparatuses and balance beams. The capabilities of these measurement techniques look very promising.
Fie, J. (1984). Synthetic boards spring past wood. Technique, 4(1), 12-13,19.
Greenwood, M., & Newton, J. W. (1996). Direct force measurement of the vault take-off in gymnastics. J. M. C. S. Abrantes Proceedings XIV International Symposium on Biomechanics in Sports (pp. 332-334). Lisbon, Portugal: Edicoes FMH Universidade Tecnica de Lisbon.
Sano, S., Ikegami, Y., Nunome, H., Apriantoni, T., & Sakurai, S. (2004). An accurate estimation of the springboard reaction force in vaulting table of gymnastics. Proceedings of XXII International Symposium of Biomechanics in Sports University of Ottawa, Ottawa, Canada: Faculty of Health Sciences, University of Ottawa, Ottawa, Canada.
Case Study: U.S. Olympic Committee Uses Polhemus LIBERTY Tracker
J.R. McNeal, Ph.D., H.A. Salo - Eastern Washington University, Dept of Physical Education, Health and Recreation. Cheney, WA.
W.A. Sands, Ph.D. – Head - Sport Biomechanics and Engineering, United States Olympic Committee, Colorado Springs, CO.
Recent literature has demonstrated that static stretching exercise may lead to an acute reduction in an individual's ability to perform activities requiring maximal strength and/or power (see Behm, Button, & Butt, 2001; Cornwell, Nelson, Heise, & Sidaway, 2001; and McNeal & Sands, 2003 for example).
Joint position sense (JPS) is a component of proprioception and is described as the individual's ability to know where his/her body parts are located in relation to each other (Lephart & Fu, 2001). This information is important for a number of practical reasons.
First, athletes and others regularly stretch as a part of their warm up and as a preventative of injury. However, if the athlete's ability to locate his/her limbs in space is compromised by stretching, then the injury prevention aspect of stretching may be questionable and stretching may be contraindicated for injury prevention. Second, in terms of performance enhancement, if stretching interferes with position sense, then those skills requiring exquisitely precise technique should not be preceded by stretching.
In order to measure one's ability to locate a limb in three-dimensional space one requires sophisticated laboratory instrumentation that is precise, robust, reliable, and easy to use. "We found that the Polhemus LIBERTY system of magnetic tracking sensors was a perfect choice.
This system provides extraordinary precision and ease of use," states Bill Sands. Advanced Motion Measurement, LLC (AMM) software was used in conjunction with the Polhemus hardware in order to render data for analysis in six degrees of freedom. This kind of motion analysis is easy to obtain with the Polhemus and AMM systems. Other biomechanical analysis systems require considerable post processing and analyze rotational motions of limbs only with great difficulty. In our study, rotational information was paramount to understanding proprioception following stretching.
The study was conducted using 21 adults, recreationally active subjects (11 male, 10 female). The study sought to determine if a subject's ability to reposition their arm in space while blindfolded differed following an acute bout of static stretching to the shoulder musculature. While traditional goniometric tools could be used to evaluate changes in joint angle, the error of measurement was considered unacceptable for the purposes of this study.
Subjects were outfitted with the Polhemus magnetic sensors. Sensors were placed on the torso (C7), upper arm, wrist, and forehead using Velcro straps (Figure 1). Anatomical landmarks were then digitized with a magnetic sensor fixed to a pen (Figure 2), so that positions could be scaled to each individual's anatomical lengths, and a robotic model of the body could be created.
"The Polhemus LIBERTY magnetic tracking system suited our unique research needs precisely. The data collection rate of 240 Hz and the precision of the data obtained were important for our study," says Bill Sands.
Subjects were seated in a chair and blindfolded using obstructed-vision swimming goggles. The seated position was used to help limit variation in trunk position while moving the arm during testing. The arm of each subject was passively placed by the principal investigator in three positions: a low position of approximately 50 degrees in the sagittal plane (Figure 3), an oblique position of approximately 110 degrees sagittal and 30 degrees of horizontal abduction, and a high position of approximately 150 degrees sagittal. The initial angles were determined goniometrically, and each individual subject's 3D coordinates were recorded in real-time to determine exact coordinate locations with the Polhemus and AMM system. The subject's arm was placed in each position three times, and each time the subject was asked to hold this position for three seconds and to remember the location so that it could be reproduced by the subject during testing.
Figure 4 shows a model drawn by the Polhemus and AMM system generated using a subject's data from the maximal passive ROM test. Data were sampled for approximately one second following verbal indication by the subject that they were at their maximal flexed position. This test was conducted as a pretest to determine if the stretching protocol actually induced a temporary increase in range of motion, and to ensure that each subject fell within published normative values for shoulder range of motion. Following range of motion testing, the subjects were statically stretched by the principle investigator in four positions (horizontal hyper-adduction, flexion, hyperextension, and horizontal hyper-abduction), with each position held for 30 seconds.
Immediately following the stretching protocol, the subject's arms were again passively placed in each of the three pre-testing positions (one repetition only) in order to remind the subjects of the required positions to be tested. Then post testing of JPS was conducted, followed by the maximal flexed range of motion test to assess the effectiveness of the stretching protocol.
Initial investigation of the data showed excellent repeatability for the maximal flexed range of motion positions, with variations in repeated trials often less than one cm (3D coordinate position of the wrist compared to the torso sensor). Data analysis will involve the determination of an absolute angle of the arm in each of the positions of interest. If appropriate, mean JPS will be calculated and compared pre to post. In addition, the variability in repeated trials of JPS may prove to be interesting, as static stretching may lead to a greater variation in JPS.
"In summary, while other more traditional biomechanical equipment could have been used to solve the research question of this study, the Polhemus and AMM system demonstrated a level of sophistication and precision that made this type of study possible and in many ways easy," states Bill Sands.
Case Study: Assisting Olympic Weightlifting With Motion Tracking
Olympic weightlifters compete in two lifts, the snatch and the clean and jerk. In both lifts the lifter begins by pulling the weighted barbell from the floor to an overhead position. A study was done with an Olympic athlete using Polhemus technology.
William A. Sands, Ph.D. - Head Sport Biomechanics and Engineering
U.S. Olympic Committee - Sport Sciences
Weightlifters compete in two lifts, the snatch and the clean and jerk. In both lifts the lifter begins by pulling the weighted barbell from the floor to an overhead position. The snatch lift is performed in one continuous movement while the clean and jerk has the athlete pull the bar to a shoulder position and then the athlete "jerks" or pushes the bar overhead to complete the lift.
Jackie Berube is an elite weightlifter training at the Olympic Training Center in Colorado Springs. Jackie has the distinction of being one of the strongest athletes, pound-for-pound, male or female we have ever tested at the Training Center. Jackie is an outstanding athlete having been a collegiate gymnast and women's wrestling world medalist. Jackie also excels at weightlifting; however she has an anatomical limitation in that her elbows will not completely extend due to bony restrictions in her elbow joints (Figure 2. Measuring Jackie Berube's elbow range of motion).
This places her at a significant disadvantage in the overhead portions of her lifts. She faces the paradoxical problem of being strong enough to get a heavy weight overhead, but unable to "lock" her elbows and thus hold the weight there for the necessary time to achieve a completed lift.
We are using Polhemus hardware and Advanced Motion Measurement software to help Jackie learn to maintain tension in her triceps and thus hold the weight aloft in spite of her elbow anatomy (Figure 2. Jackie holding the bar overhead while instrumented).
The high sampling rate of the Polhemus LIBERTY (240Hz) allows Jackie and her coaches to see her movement with the clarity that slow motion provides.
The Polhemus and Advanced Motion Measurement system allow us to monitor her lifts in real time and thus provide her with nearly instantaneous feedback regarding her body position and elbow movements.
We have worked with her to establish a wider grip and more awareness of her arm and elbow movements. The tracking system permits Jackie to perform each lift with immediate feedback on how she did, and then see her body position changes immediately after each lift on a laptop computer.
The coaches have been staggered by the system's ability to render a lifter in a "robot" shape that makes the image more recognizable and easy to analyze using a trained coach's eye.
Jackie's awareness of her arm positions, the tension required to support the weight, and the speed with which she must attain and maintain tension in her triceps has improved markedly and we are monitoring her development every few weeks.
The high sampling rate of the Polhemus LIBERTY (240Hz) allows Jackie and her coaches to see her movement with the clarity that slow motion provides.The Sport Sciences Division of the USOC is also developing this same technology to help pistol shooters track their arm, hand, and gun motions.
CASE STUDY: USING POSTURE AND BEHAVIOR TO INFORM AFFECTIVE COMPUTERS BY PREDICTING HUMAN INTENTION
Affective computing is a research area in computing which suggests that for computers to be able to perform at a level of interaction more natural for people, and for computers to be genuinely intelligent, they must have the ability to recognize, understand, and even to have and express emotions (Picard 1997). Polhemus LIBERTY was utilized in this study.
T D Jones and S W Lawson
School of Computing, Napier University, Edinburgh
Key Results: Preliminary experiments show that an affective computer system is capable of monitoring human posture and successfully outputting the correct posture classification to match the movement being exhibited.
How does the work advance the state-of-the-art: Affective computers can predict the intention of a person through the behavior that the person exhibits and provide a service or function based on the recognition of the action to be performed.
Motivation (problems addressed): A single class of behavior can be exhibited in varied ways by different people; recognition of a particular movement that can be performed in diverse ways will also have to adjust to varying speeds of the same behavior and alternate motions that comprise it.
The context in which behavior is performed is also paramount in defining the outcome of the intended action; an affective computer would need to have sufficient data of the context in which a person is situated.
Affective computing is a research area in computing which suggests that for computers to be able to perform at a level of interaction more natural for people, and for computers to be genuinely intelligent, they must have the ability to recognize, understand, and even to have and express emotions (Picard 1997).
Behavior is an expression of our emotions and can provide others with a certain amount of information about their state of mind. A person's posture and behavior can inform those around them of their intended actions, such is to say that a human can predict the actions of another by interpreting their movements based on previous experience.
The aim of the research introduced in this paper is to capture human behavior using sensors that will record a performed movement. This data will be processed automatically by an affective computer which will attempt to predict the intention of the person from their exhibited behavior.
The remainder of this paper describes the apparatus and experimental procedure adopted for the research, it then discusses the results of some preliminary experiments and concludes with proposed future work.
Apparatus and Experimental Procedure
To capture behaviors, a Polhemus LIBERTY system was used, which was equipped with eight independent sensors, measuring six degrees or reference: spatial coordinates X,Y,Z and orientation coordinates X,Y,Z; each sensor is capable of producing 240 updates per second. Fig. 1: Shows Polhemus Liberty sensors attached to subject.
Two behaviors were captured from six subjects: a punch and a handshake. Three sensors were strapped to the right arm (Fig. 1), the first positioned on the hand (sensor A), the second on the upper forearm (sensor B), and the third on the upper arm (sensor C).
The sensors relay their information in relation to a stationary transmitter which produces a low electromagnetic frequency.
Results and Discussion
The data gathered by the Polhemus equipment was analysed offline. Fig. 2 shows the data produced by a punch for (sensor A) only, which was attached to the hand.
The X coordinate shows the movement of the hand travelling directly toward the punch bag. The Y coordinate shows the hand moving back behind the body and then its trajectory as it moves forward and upwards to the target, and the Z coordinate shows the height of the hand as it moves backwards and up and then travels forward towards the target. Fig. 2: Results of punch behavior
Fig. 3 shows the data produced by a handshake for sensor A only, which was attached to the hand.
The X coordinate shows the hand travelling toward the target by crossing in front of their body, indicated by the upwards slope on the graph. The Y coordinate shows the forward motion of the hand. The Z coordinate show the height of the hand to the point of contact, indicated by the first line and then one shake of the hands to a rest position, the second line. Fig. 3: Results of handshake behavior
For each subject the data was analysed and compared with their repetitions. Next, the data was analysed against other test subjects data for comparison. Preliminary results show there is very little variation between individuals repetitions; overall, there are small variations between test subjects performing the same behavior.
For a computer to be able to predict behavior it must first be able to recognize the behaviors and make sense of them. To do this the data gathered so far will be used as training sets for programs such as neural and probabilistic networks (Rumelhart 1986), (Speckt 1990). Once the networks are trained they will be fed data from more tests in an attempt to achieve the highest percentage of recognition. Once this has been achieved the data will be streamlined for the least data required to perform the same result. Finally, the networks will then be trained to predict behavior, it is intended that a real time system will be created to demonstrate this.
The data gathered has shown that it is possible to recognize human behavior and determine the trajectory of movement throughout all phases of the behavior being exhibited. If an autonomous affective computer system can successfully process this data it should be possible to have a system that can recognize and predict human behavior.
Picard, R. W. (1997) Affective Computing. MIT Press.
Rumelhart, D. E., McClelland, J. (1986). Parallel Distributed Processing.Cambridge, MA: MIT Press. 1.
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Case Study: Vermont Air National Guard Uses Polhemus SCOUT in F-16 Simulators
The Vermont Air National Guard (ANG) uses over 90 MetaVR™ Virtual Reality Scene Generator™ (VRSG)™ licenses in their four-ship simulators at the new F-16 Mission Training Center (MTC) located at the VT Air National Guard (ANG) facilities at the Burlington International Airport, Burlington, VT.
The F-16 MTC officially opened on June 4, 2010 with a ceremony that included U.S. Sen. Patrick Leahy, Lt. Gen. Christopher D. Miller, the Air Force's deputy chief of staff for strategic plans and programs, and top National Guard officials. MetaVR and International Simulation & Training Systems (ISTS, the subcontractor that built the simulators) were given awards for engineering excellence.
Figure 1: One of four cockpit simulators at the new F-16 MTC, located at the ANG base at the Burlington International Airport, Burlington, VT. The multi-channel synchronized view, driven by VRSG, is rendering the VT virtual terrain built by MetaVR. Photo courtesy of MetaVR; photo credit to SSgt. Dan DiPetro, 158 FW, Vermont National Guard.
About the Simulators
The site consists of four F-16 full mission trainers, instructor/operator stations (IOS) for each cockpit, and an after-action review capability. Each cockpit consists of a 360-degree wraparound display based on the A-10C FMT seamless M2-DART display. The original M2-DART display used one projector for each of the eight display facets. The contractor team enhanced this design by using two or three projectors on each of the eight display facets, for a total of 18 HD projectors.
Figure 2: Inside the new F-16 MTC, located at the ANG base at Burlington International Airport, Burlington, VT. Photo courtesy of MetaVR; photo credit to SSgt. Dan DiPetro, 158 FW, Vermont National Guard.
Inside the wraparound display sets a high-fidelity cockpit with functional buttons, switches, and multi-function displays (MFDs). The MFDs can display targeting pod video in electro-optic (EO), infrared (IR), or ground-mapping radar. An instructor/operator station (IOS) exists for each cockpit. The IOS establishes the environment the simulator will fly in, to include geographic location, weather, and time-of-day. The IOS also controls the threat environment using the AFRL XCITE target generator. The IOS includes a large flat-screen TV that can simultaneously display a replica of out-the window scene, heads-up display, and both multi-function displays.
Unique to this installation is its novel approach to night vision goggle (NVG) training. The visual system uses a stimulate approach rather than simulate approach to NVG training. The pilot wears his real NVGs while in the cockpit, so he can become accustomed to the form-factor and limited field-of-view.
Using the Polhemus SCOUT tracker, the pilot is head-tracked with 6 degrees-of-freedom, enabling the image generator to know at any moment the exact location and viewing direction of the pilot's head.
The Polhemus SCOUT tracker is an AC magnetic head tracker that requires no mapping effort to run at high accuracy within the full mission simulators. The image generator renders an NVG area of interest (AOI) inside a cone visible to the goggles. Imagery rendered inside the NVG AOI is modified to stimulate NVGs and display covert lights. Imagery rendered outside the NVG AOI is rendered as normal unaided-eye, and covert lights are not visible outside the NVG AOI. This forces the pilots to look through the NVGs to be able to see the scene in sufficient detail at night for flying.
About the VT ANG Database
MetaVR has built and delivered to the Vermont Air National Guard 3D terrain of the ANG base facilities and airfield at the Burlington International Airport, Burlington, VT.
The 6-geocell Metadesic-formatted 3D terrain, built with MetaVR's Terrain Tools for ArcGIS is comprised of 47 GB of data of Vermont and upstate New York, with 60-meters post spacing, 1-meter imagery with a 0.5-meter imagery inset of the Vermont Air National Guard airfield and base facilities. The Vermont Air National Guard uses the terrain for its F-16C simulation-based training. Figure 3: Real-time aerial view in VRSG of the virtual Vermont ANG base and airfield, with Lake Champlain visible in the background. Photo courtesy of MetaVR
About the Models
The virtual terrain contains approximately 45-high resolution, geolocated models of hangars, offices, storage facilities, and other buildings in the area, a high-resolution F-16C aircraft model, and the runway. In addition, the virtual terrain includes the commercial air terminal, and approximately 40 other models of elements at Burlington International Airport such as runway lights, street light, signs, and trees. Figure 4: Real-time VRSG rendering of an F-16 entity taking off from the runway of the virtual Vermont ANG airfield. Photo courtesy of MetaVR
All site-specific models were created with textures derived from high-resolution photographs taken at the site, at ground level, with a 10-megapixel camera. The models were built with industry standard 3D modeling tools such as Autodesk, Maya and 3D Studio Max. Content from MetaVR's 3D model libraries is also used on the terrain.
For simulating night scenes, the terrain contains thousands of cultural light points of the airport and the Greater Burlington area. VSRG has an ephemeris model to predict moon position and phase, and populates the sky with a 40,000 light-point star field. The cultural lights, moon disk, and star field enable trainees in the cockpit simulator to fly the area at night with accurate celestial references and provide realistic simulation of actual night vision goggles. Figure 5: View at dusk of the hangar, from across the runway. Photo courtesy of MetaVR
To geolocate many of the elements on the airfield terrain to match the ones on the actual airfield itself, an interactive panoramic view was created from photos taken at the site as a reference, using photo-stitching software.
MetaVR Terrain Tools for ESRI ArcGIS was used to create the terrain mesh, which includes a high resolution representation of the Lake Champlain coastline. At runtime, VRSG Metadesic generates multi-textured, animated, normal-mapped water surfaces in the cutout regions identified as water. The terrain tiles seamlessly match with the water tiles generated by VRSG. Figure 6: Night scene of the commercial terminal at the virtual Burlington International Airport. Photo courtesy of MetaVR
Figure 7: The panoramic view was mapped onto a 3D cylindrical model, resulting in a 360 degree virtual view, or model that could be examined as a reference for placing models on the terrain. Photo courtesy of MetaVR
Figure 8: VRSG real-time aerial view of the virtual shoreline region of Lake Champlain, Burlington, Vermont. Photo courtesy of MetaVR
Case Study: PATRIOT™ Tracks the Positioning of Ultrasound Probe for Training and Simulation System
Historically, ultrasound training has been a challenging task; training on real-life patients can be difficult and alternative forms of training did not exist. MedSim changed this and revolutionized training for ultrasound users. With their flagship product, UltraSim®, MedSim was the first to pioneer the use of simulation for ultrasound training. The Polhemus PATRIOT system was used.
MedSim—Pioneers in Ultrasound Simulation Training
The ability to simulate ultrasound training was an important break-through for health care. An advantage of simulated ultrasound training is it allows trainees to practice with various types of situations—everything from normal to abnormal cases.
The UltraSim provides a realistic environment that looks and feels as it would with a real patient. For example, with a simulated obstetrical exam, the screen image is identical to that of a real fetus using real ultrasound equipment. The trainee can scan an entire fetus’s anatomy.
“The UltraSim simulates the functions of a conventional ultrasound machine, allowing students to perform sonographic examinations on a mannequin. The UltraSim is a self-guided simulator that gives students realistic hands-on ultrasound scanning experience without the need for live patients.
The scanning techniques used by the students simulate the same skills necessary to examine a patient in a clinical setting,” said Denise Levine, Sales Manager, North America, MedSim Inc.
UltraSim Powered by Polhemus PATRIOT—6DOF, Cost Effective Tracking Solution
After evaluating various technology options for UltraSim, MedSim selected Polhemus motion tracking technology to power UltraSim. PATRIOT provides the necessary six-degree-of-freedom tracking and its combined performance and affordability made it the top choice.
There are multiple advantages of using the PATRIOT system in a training simulator—the small size and portability of the entire system, the affordable price, and the unique ability to embed the sensor inside the probe.
Because Polhemus proprietary technology is electromagnetic based, the sensor can be embedded into a custom form factor. This made the PATRIOT a perfect fit for MedSim’s UltraSim.
The PATRIOT precisely tracks the position and orientation of the mock ultrasound probe relative to an anatomically correct training mannequin.
The UltraSim system uses this probe position data to change the ultrasound image accordingly. MedSim’s UltraSim delivers the much needed ultrasound scanning experience and the ability to identify and examine different anatomic areas with standard ultrasound equipment settings, controls and functions. (Image shows MedSim Ultrasound Probe with embedded sensor).
UltraSim—Also Aids in Quality Assurance
According to Levine, “Instructors can measure and monitor the student’s skills and progression. The simulator is a valuable tool that provides standardized, non-subjective evaluations of the student’s scanning abilities.” This aids in quality assurance and is helpful to medical organizations that accredit professionals in procedures and examination techniques. There are many benefits to the trainers, trainees, and the hospitals, but the real benefit translates to the future patients who will be examined by a competent, well-trained technician.
MedSim is a leading simulation design company with a history in various industries as diverse as defense avionics and medical training technology. Former parent company, Hadas Avionics, designed simulation systems for training fighter pilots to control the sophisticated weapon systems of attack aircraft. MedSim is focused on furthering the development and use of its simulation technologies in industries where high performance and accountability are crucial.
After being spun-off by Israeli-based Hadas Avionics in 1994, MedSim began designing medical training simulation devices. MedSim’s focus is advanced medical simulation devices and its first product, UltraSim, an ultrasound simulation device, was launched in November 1995. With UltraSim, allied health departments, medical schools and hospitals can use this real-time simulation training device to improve their student residents and physician’s ultrasound imaging and diagnostic techniques. MedSim UltraSim units are sold and used worldwide. UltraSim system and probe images courtesy of MedSim.
Case Study published with permission of MedSim
Case Study: SimSurgery Finds Success with SEP Simulator—Powered by Polhemus PATRIOT
Polhemus is proud to provide the enabling technology for training and simulation. Polhemus technology powers the SEP Simulator, which allows surgical students to train and learn surgical skills. When reviewing tracking options, PATRIOT was top choice.
If you were going in for major surgery, would you like the reassurance that your surgeon had already logged plenty of training time and had achieved a high level of proficiency on the procedure? Thankfully, companies like SimSurgery are helping to provide additional, innovative training options for surgeons through simulation. SimSurgery is not new to training and simulation; they’ve been developing quality products for surgical simulation since 1999.
Headquartered in Norway, they also have offices in Germany and the U.S. The company is constantly upgrading and developing new products, which are based on the SimSurgery Educational Platform, otherwise known as SEP--an award winning training and educational platform for laparoscopic and robotic surgery.
Polhemus PATRIOT System Powers SEP Simulator
Polhemus is proud to provide the enabling technology that powers SEP. SimSurgery uses the Polhemus PATRIOT system in the SEP simulator. Specifically, the SEP system allows surgical students to train and learn surgical skills, such as hand-eye coordination, use of endoscope and surgical instruments, tissue manipulation, and other procedural skills before operating on patients.
The PATRIOT sensors are not only easily embedded, but due to the true 6DOF, the SEP system can track both position and orientation of laparoscopic instruments. Vidar Sorhus, PhD
Why PATRIOT Over Other Motion Tracking Systems?
When reviewing tracking options, PATRIOT was top choice. According to Vidar Sorhus, PhD, CTO, SimSurgery, “The reason for this selection is the combination of performance, cost, and size of the PATRIOT system--we needed a system with two trackers that we could embed into our simulation hardware.”
The PATRIOT sensors are not only easily embedded, but due to the true 6DOF the PATRIOT delivers, the SEP system can track both position and orientation of laparoscopic instruments. The tracked position and orientation data is used as input to real-time 3D simulation of surgical techniques and procedures.
For this application, SimSurgery needed a high level of accuracy and repeatability of position and orientation values, as well as a high update rate. PATRIOT was the perfect solution to achieve this.
According to Vidar Sorhus of SimSurgery, "A great advantage of the PATRIOT tracking system used in SEP is that it measures the position and orientation of the free instruments without having the instruments anchored in a mechanical measurement system. This feature makes the simulator user interface very flexible and allows the user to freely select an instrument port. As a consequence, the system can be used to simulate scenarios with any port configurations, including single incision laparoscopic surgery."
The SimSurgery laparoscopy simulator, combined with the SEP learning concept is based on validated educational principles. It is a unique tool for minimally invasive surgery training and performance evaluation. SEP allows for proficiency based training, providing surgeons the opportunity to increase competency at every level. Today, SEP is being used at leading institutions in the U.S., Europe, and Asia. For more information about SimSurgery and their products, visit: SimSurgery.
Case Study: Polhemus PATRIOT Beats Competition for Virtual Reality Application
Virtual reality products have always been the leader in the market, but the technology used in the original units, created ten years ago, was extremely outdated. Arcadian Virtual Reality, L.L.C. provides virtual reality entertainment. Recognized around the world as the industry leader in Location Based Entertainment, Arcadian uses Virtuality™ equipment, originally developed by Virtuality Entertainment, LTD.
Virtuality products have always been the leader in the market, but the technology used in the original units, created ten years ago, was extremely outdated. Polhemus InsideTrak boards could no longer be purchased along with other devices and Arcadian was faced with the challenge of producing a brand new product and had to shop for alternative components.
Already using the InsideTrak for head and hand positioning in their software experiences, Arcadian had to find a new unit that would be comparable to the previous products without sacrificing quality or price. When researching for a new tracking device, Arcadian technicians began scouring the market for the best available products. They quickly identified some key issues.
"As we have used the InsideTrak in past products, we looked for an integrated solution first. This would help us keep external components to a minimum, as the overall appearance of our system is a priority, but an integrated solution was unavailable," said Jared Hargrave, president of Arcadian VR.
"We began looking at the PATRIOT™, a newly released product from Polhemus. Even though this was not an integrated option, the footprint was small enough that we would be able to place it inside of our unit. This accomplished our first goal."
The second goal was serviceability. Arcadian found many products that would provide tracking solutions adequately, but none were easily replaced or repaired. The USB and RS-232 compatibility of the PATRIOT was perfect for their installation. Arcadian was able to quickly replace the unit and its components. The sensors and source generator were simply plugged into the unit, not hard wired. The ability to swap components in a short time accomplished their second goal.
Tracking systems have often had problems with Degree-Of-Freedom (DOF) levels. Arcadian found multiple products that provided 3DOF, none of which suited their needs. In order to provide a reliable virtual reality experience, they needed a 6DOF tracking solution.
"After testing products by other vendors, the PATRIOT quickly became our solution," stated Hargrave. "It provided our 6DOF solution at a superb update rate of 60Hz with a 12 millisecond latency. As for refresh rate, the PATRIOT outperformed any other product we tested. Our third goal was quickly realized."
The Arcadian software experience often requires the user to hold their hand(s) outstretched. With a tracking sensor on the hand, this often created interaction complications with products from other vendors. Since the PATRIOT provides a range of up to four feet with accuracy, their fourth goal was met. Arcadian products are internationally known, so they had to provide a system that would work in European markets. The PATRIOT provided a built-in solution, being able to operate on U.S. power systems (120 volts) and European systems (240 volts). Arcadian found they could seamlessly integrate this product into their new design.
The final and most important goal identified was ease of programming. "In the past, we had to write our own source code for tracking devices, taking much time and resources. With the need to push a product as quickly as possible, and an SDK included with the PATRIOT, with well documented code available," noted Hargrave, "we could integrate the tracking system into our experiences as quickly as possible. PATRIOT has proven to be the solution."
Case Study: Users Can Use Their Body To Navigate Using ChairIO, for Virtual Environments
The chairIO is a hands-free travel interface used in Virtual Environments (VE) where the body is used to navigate. This is a project that has been developed by the interactive media/virtual environment group which was founded in February 2004 at the University of Hamburg, Germany. It is part of the department of informatics. Three scientists and several students work on projects , teach and learn in the areas of human-centered Human-Computer Interaction, Computer Graphics, Virtual Environment Systems and Technology, Interactive Storytelling, and Art. The Polhemus PATRIOT motion tracking system was used for this application.
Navigation is one of the most important tasks in VE. The chairIO project is an interface based on a commercially available seat, the Swopper™, and the Polhemus PATRIOT, a two-sensor motion tracking product. The Swopper stool is an ergonomic seat for use in an office environment. It has a rotatable seat, 360º pivot point, height and damping adjustment, and a linkage arm consisting of a spring/shock combination. The seat can tilt in any direction and the spring/damper system allows the user to bounce. The seat itself is on a rotational system on top of the linkage arm, allowing it to independently rotate.
To operate the chairIO, the user sits on the device and, by shifting body weight, tilts it in any direction or rotates the seat. This physical movement of the seat is mapped to viewpoint/direction movement in the game environment. For example, the sensation of forward movement is achieved by moving your body forward and tilting the seat forward. Rotating the view requires slightly rotating the seat, thereby triggering slower or faster rotation of the view in that direction.
For a 3D ground-following movement, this method is easy and highly intuitive to use and, furthermore, is fun. The movement is computationally divided into the component translation and rotation. Translation of the current viewpoint is performed by tilting the seat in any direction and translation speed is non-linearly mapped in relationship to how far in the direction of the desired travel the user tilts the stool.
In an area surrounding the center the mapping is linear; thereafter, the distance is mapped as linear plus a cubic factor. This allows the user to travel at higher speeds by tilting the seat further in the direction of travel.
The PATRIOT determines the position and orientation of the seat using two points on the seat. This method was chosen primarily for its robustness in initializing the interface, as it is not position dependent and allows re-adjustment of the seat's height and of the seat itself. An initialization procedure sets a few values used in the calculation, such as the rotation of the seat and the position of the Swopper.
Based on these variables the PATRIOT provides the translational component from the initial position. The rotation of the seat is calculated by applying the inverse tilt transform to the seat and comparison with the initial rotation. Future plans include integrating low-price standard sensors into the chair.
The software written to connect the interface to Linux or Windows® applications makes use of VRPN. For Windows, PPJoyis was used to present the chairIO data as joystick data to applications.
For more information on University of Hamburg chairIO project please visit http://imve.informatik.uni-hamburg.de/projects/chairIO/index.htm.
Case Study: China’s Agriculture Studies Use Fastrak
The Polhemus FASTRAK® system was used as a digitizer for studies conducted in China to study agriculture, specifically the study of plant growth under different climate and soil conditions.
Study #1: Corn Growth
Xiping Wang, from the College of Resources and Environmental Sciences in Shijiazhuang, China, used FASTRAK® in a study to estimate the photosynthetic active reactions in corn. Wang used a 3D model of the corn to measure the above-ground architecture of the plants with coordinates of points on the leaves and cobs using the FASTRAK® as a digitizer. With this information, Wang’s team was able to create a highly detailed 3D digital model of the corn stalks, along with different intensity levels of sunlight that came in contact with each leaf.
Total incident PPFD intercepted by individual leaves for a selected plant in low density MSP (measured subplot) canopy generated by 3DIRMS model at noon on August 8, 2002. ("Estimating photosynthetically active rediation distribution in maize canopies by a three-dimensional incident radiation model," Xiping Wang, Yan Guo, Xiyong Wang, Yuntao Ma, Baoguo Li. 2008.)
The study concluded that planting the corn closer together had an effect on the height of the corn’s growth and the size of the leaves, resulting in taller plants with smaller leaves.
The corn that was planted in a lower density was shorter, with larger leaves and had a higher percentage of sun at the base compared to the more densely planted corn. However, Wang’s team found the more densely planted corn had a higher percentage of sun at the upper portion of the plants.
The test data allowed Wang and his team to create a simulated model which is able to show similar results given the estimated density of the planted corn.
Study #2: Rice Growth
A study of hybrid rice using a spatial light model based on 3D digitizing, by Bangyou Zheng, from the College of Resources and Environment, China Agricultural University in Beijing, China, used FASTRAK® as a digitizer. Zheng’s team collected strategic points on the rice plant along with the topological information of the study area.
The team used nine plants at various stages of growth, digitizing and measuring four to ten points on each stem. The distance between points was no more than 1 cm. Two people digitizing nine plants took less than ten hours to complete the measurements at each stage of growth.
Three-dimensional reconstructions of an individual rice plant and rice stand based on the 3D digitized data. Example was from Y58S/9311 at the filling stage. ("Comparison of architecture among different cultivars of hybrid rice using a spatial light model based on 3-D digitising," Bangyou Zheng, Lijuan Shi, Yuntao Ma, Qiyun Deng, Baoguo Li, Yan Guo. 2008).
Zheng’s study concluded that the “3D digitizing technology can be used to quantify rice architecture in a paddy field.”
The study showed that the rice plants with steeper leaf angles allowed light to easily penetrate the plant more deeply. This significantly enhanced the photosynthesis at the lower portion of the plant during a higher angle of the sun, and resulted in a more uniform light distribution within a densely planted rice field.
Study #1: Corn Growth ("Estimating photosynthetically active rediation distribution in maize canopies by a three-dimensional incident radiation model," Xiping Wang, Yan Guo, Xiyong Wang, Yuntao Ma, Baoguo Li. 2008.)
Study #2: Rice Growth ("Comparison of architecture among different cultivars of hybrid rice using a spatial light model based on 3-D digitising," Bangyou Zheng, Lijuan Shi, Yuntao Ma, Qiyun Deng, Baoguo Li, Yan Guo. 2008.)
Case Study: Motion Tracking Enables Measurement of the Effectiveness of Brain Stimulation Therapy
Polhemus motion tracking technology is used to enable motion measurement in a neuroscience application. Research in this area of neuroscience has been particularly challenging in the past. A method for capturing body movement three-dimensionally and correlating it with a patient’s brain wave activity is a significant advancement in understanding therapeutic effectiveness.
Imagine holding a cup of coffee, and just as you begin to take a sip, your hand begins to tremble uncontrollably. It’s this type of simple daily task that leaves Parkinson’s Disease patients feeling frustrated and asking for answers--from doctors and the research community.
At the Institute for Neural Computation in La Jolla, California, the approach is to analyze the normal motor control and learning processes, and the nature of the breakdown in those processes in patients with selective failure of specific sensory of motorsystems of the brain. (from Poizner Lab website).
Working with the patients after the surgery enables Dr. Poizner to evaluate the effectiveness of Brain Stimulation Therapy. By using Polhemus precision motion tracking technology, Dr. Poizner is able to measure and evaluate how well the therapy is working. By connecting the light-weight and unencumbering Polhemus sensors to the patient’s hand, for example, he is able to capture quantitative data and analyze the degree of trembling the patient experiences, down to the slightest of movements. Dr. Poizner then reports this quantitative data to the clinical side, providing critical insight into how well the therapy is working.
Polhemus’ proprietary electromagnetic technology is ideal for this type of work because of its high level of accuracy and ability to produce repeatable results.
When selecting the precision motion tracker for this research project, Dr. Poizner said, “It was important that we accurately tracked in space without any line of sight occlusions. This is very high tech—as it measures the most subtle movement.”
Dr. Poizner has used various Polhemus motion tracking products, including:
- FASTRAK®—used to digitize positions of EEG electrodes
- LIBERTY™—both 8- and 16- sensor systems used for measuring patient reach and grasp, and other biomechanical metrics
Research in this area of neuroscience has been particularly challenging in the past. A method for capturing body movement three-dimensionally and correlating it with a patient’s brain wave activity will be a significant advancement in understanding therapeutic effectiveness.
According to Dr. Poizner, “The ultimate goal was to be able to quickly and cheaply provide an assessment in a quantitative, correlated, rigorous fashion.”
This study of Measuring the Effectiveness of Brain Stimulation Therapy was presented at the 2010 Neuroscience Show in San Diego, California.
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Case Study: Compumedics NeuroScan & Polhemus FASTRAK enables Medical Research Applications
Using Polhemus technology, NeuroScan was able to be the first in the industry to produce a three dimensional image of a subject's head. "For the first time, we can quickly take EEG data and overlay it on a MR image for an exact definition of where electrical activity is coming," said Stephen Sands, Chief Scientist.
Background: Compumedics NeuroScan, formerly known as NeuroScan, Inc., was established in 1988 to pursue the development and sale of advanced computer software and apparatus to assist in understanding the electrophysiological functioning of the brain.
The company has expanded its focus to now provide products for the new topic of "multimodal neuroimaging," encompassing electrophysiological technology (EEG and Evoked Potentials), magnetic resonance imaging (MRI, both functional and anatomical), positron emission tomography (PET), magnetoencephalography (MEG) and computer tomography (CT). The company's mission is to provide neuroimaging for medical research.
The Polhemus Motion Capture Solution
In 1992, NeuroScan received a contract from the National Institute of Neurological Disorders and Strokes (a division of the National Institute of Health) to build the first commercial 128 channel EEG/EP system. As part of this new system, NeuroScan made the decision to incorporate into the product exact electrode placement on the head to provide the highest quality and most accurate recording available.
After researching products on the market that would aid them in building this high accuracy component, NeuroScan selected the Polhemus ISOTRAK™ solution, a 3D motion tracking and digitizing system. Later, with the introduction of the Polhemus FASTRAK®, a system offering higher speed and accuracy, NeuroScan decided to upgrade to incorporate the highest accuracy system on the market.
Using Polhemus technology, NeuroScan was the first in the industry to produce a 3D image of a subject's head and define the exact location of electrodes placed on the subject.
The Polhemus Advantage
"For the first time we can quickly take EEG data and overlay it on a MR image for an exact definition of where electrical activity is coming," said Dr. Stephen Sands, Chief Scientist. "Before using Polhemus' solutions, this was a long and difficult process to accurately calculate this activity."
For example, the Polhemus data can be read by its new Current Reconstruction and Imaging (CURRY) software. CURRY is a powerful package which allows users to combine the results of EEG/MEG measurements with image modalities such as MRI and CT. The result is a realistic 3D view of brain electrical activity.
"MRI takes a snapshot of the brain at every second, giving a read out of the structure of the brain," said Sands. "While EEG works in milliseconds, which allows one to view the brain as it is actually functioning; by combining the two, you have a more accurate understanding of the brain's activity. Using Polhemus within our products, we are taking several steps forward in better understanding how the brain works."
FASTRAK is an award-winning 3D motion tracking and digitizing system that offers high speed, high accuracy, and low latency using one to four receivers for medical, animation, simulation and motion capture applications. Because accuracy was critical to NeuroScan's needs, the FASTRAK was an ideal solution.
"With FASTRAK, we believe we have the highest accuracy solution, bar none. Accuracy is imperative to the success of our products and is particularly important when understanding the brain." Dr. Stephen Sands
NeuroScan has achieved great success using Polhemus' solutions. Today, NeuroScan's products are used by over 1500 leading universities and research institutes around the world.
"We look forward to working with Polhemus products," said Sands. "We have been very happy with not only the products themselves, but also with the technical support as well. We will continue to work closely with Polhemus in our future endeavors."
Case Study: Polhemus Tracking System Used in Biomechanics Research
Skill Technologies' client base was primarily research oriented so it was critical they had the advantage of true real-time motion analysis. Polhemus FASTRAK enabled this with the ability to accurately compute the position and orientation of a tiny receiver as it moves through space.
Advanced Motion Measurement LLC, formerly known as Skill Technologies, was founded in 1991, developing innovative real-time, 6 Degree-Of-Freedom (6DOF) motion analysis systems. Skill's product family includes 6D-RESEARCH™, 3D-SPINE™ and 3D-GOLF™ which are utilized by companies around the world for research, clinical, sports analysis and teaching purposes.
The Need for Motion Capture
As an Olympic gymnast for Australia in both the Montreal and Moscow games, Phillip Cheetham knew first-hand about human motion and its effects on the body as a whole. Also, as former head of engineering for the U.S. Olympic Committee Sports Sciences Program and former Chairman and co-founder of a leading video motion measurement company, he had the background necessary to see the importance and need for a generalized true real-time motion analysis system. In 1991, Phillip Cheetham and his brother Stephen, started Skill Technologies with the mission to provide the most innovative biomechanics and motion analysis systems on the market.
In the early 90's, the Cheethams were relying on video analysis to work with their biomechanics and motion analysis systems. In researching ways to more fully utilize 6DOF motion tracking, the Cheethams realized that a real-time electromagnetic solution would significantly enhance their software products.
"We have had a lot of experience with video motion analysis companies," stated Stephen Cheetham. "We consider video technology to be old technology in comparison to the advanced real-time capabilities that Polhemus offers with its magnetic solutions."
The Polhemus Solution
Skill's client base is primarily research oriented; therefore, it was critical that they had the advantage of true real-time motion analysis. The Polhemus FASTRAK® offers users the ability to accurately compute the position and orientation of a tiny receiver as it moves through space. This device virtually eliminates the problem of latency as it provides dynamic, real-time measurement of position and orientation.
"Polhemus offers us 6 Degree-Of-Freedom, real-time motion capture," said Cheetham. "That is critical to the biomechanics community and the clinical world. Our customers don't have the time to deal with the extensive and tedious post-processing required of other solutions on the market. Polhemus' dynamic capabilities are integral to our customer's success."
With 6D-RESEARCH, Skill Technologies provides a means to track, quantify, display and document true 3D motion of the human body, in real-time. It provides an accurate three-dimensional, 6DOF system that captures and dynamically displays motion using fully rendered 3D graphical models and parameter graphs. 6D-RESEARCH allows the user to define a body segment for each sensor. The segments are then scaled and positioned, creating a precise fully rendered 3D graphic model that moves simultaneously with the subject.
This is critical for Skill's growing customer base which includes leading providers of biomechanics, kinesiology, sports medicine, physical therapy, sports instructors and others. For example, the University of Connecticut's Department of Psychology is using 6D-RESEARCH to study postural control and limb proprioception. In this study, the university is researching how the human body "knows" where the different parts of the body are located.
Another example is the University of Alberta, Canada's, division of neuroscience using it to measure 3D tremor in patient's hands, wrists and arms to study diseases such as Parkinson's Disease. By being able to measure the actual intensity of the tremor, they can determine the precise amount of drugs needed to treat the disease, resulting in tremendous cost-savings for very expensive medication.
A very innovative application of the Polhemus FASTRAK is in Skill's latest product called 3D-GOLF. 3D-GOLF is a virtual golf training and swing analysis system that can be used by golf teaching professionals. Its most unique feature is its biofeedback capability, which is provided by FASTRAK's real-time response. The biofeedback mode utilizes audio tones to help the student hear and "feel" a good swing. When a student deviates from the specified movement envelope the computer beeps. This facilitates better teaching and faster learning.
Case Study: FASTRAK used for Position and Orientation Tracking in the VR Haptic Workstation
The Haptic Workstation was a ground-breaking 3D haptics innovation from Immersion Corporation. It's a fully integrated simulation system providing right and left whole-hand force feedback, immersive 3D viewing. The Polhemus FASTRAK was used as the motion tracking solution.
Founded in 1993, Immersion Corporation develops hardware and software technologies that improve the way people interact with computers. Immersion is revolutionizing the way one interacts with digital devices of all types. Typically in Virtual Reality, one uses two senses when computing: sight and hearing. Immersion's TouchSense™ technology engages a third sense - touch - to give you a more complete, intuitive experience.
The Haptic Workstation is a ground-breaking 3D haptics innovation from Immersion Corporation. It is a fully integrated simulation system providing right and left whole-hand force feedback, immersive 3D viewing, and easy to use CAD model manipulation and interaction software. Immersive 3D viewing is provided by a head-mounted display. The Polhemus FASTRAK® is used to find the position of the head-mounted display in real-time. Immersion offers other hardware solutions where the Polhemus FASTRAK is used to track position and orientation of the users' hands.
The FASTRAK is the industry standard, providing the most accurate electromagnetic motion tracking solution. With an accuracy of .03 inches RMS, 4ms latency, and resolution of .0002 inches per inch, this is the most precise device of its kind.
Case Study: Fakespace ImmersaDesk M1 Harnesses the Power of Polhemus Technology
In order to provide optional head tracking for its customers, Fakespace Systems, Inc., an Iowa-based company, needed to find a tracking system compatible with their product, a virtual modeling station. In creating the ImmersaDesk M1, Fakespace faced several challenges and choices. The solution was the Polhemus FASTRAK system.
The ImmersaDesk™ is a versatile, fixed or portable virtual modeling station ideal for development and engineering review applications. Small enough to fit into an office, the self-contained M1 offers a large 44" high-resolution visualization screen. The desktop angle is adjustable to suit any work style or viewing preference.
Optional head tracking facilitates the correct perspective of stereo imaging as you navigate naturally around the desk. These optional tracking systems also facilitate the use of various interaction devices such as the stylus (Polhemus), V-Wand™, and CubicMouse™. The folding design allows for easy room-to-room movement, storage or transport.
The M1 solution is ideal for a number of different applications including;
- Virtual Prototyping
How the Polhemus FASTRAK Worked for Fakespace
In creating the ImmersaDesk M1, Fakespace faced several challenges and choices. In order to provide optional head tracking for its customers, FakeSpace needed to find a tracking system compatible with their product. Since acoustic tracking was too easily affected by occlusion and internal acoustic was too expensive, FakeSpace realized that the price and versatility of the Polhemus FASTRAK® provided the best options in a motion tracking system for their product.
Fakespace went with the Polhemus FASTRAK system for a few reasons. First, many of the tracking systems available from other companies did not work with the active stereo shutter glasses. Additionally, most of the drivers offered were not readily available for other types of tracking systems. Although the FASTRAK system already held these advantages over its competitors, it was also less expensive. In conclusion, FakeSpace went with the greatest functionality at the best price.
Case Study: The Johnson Center for Virtual Reality—Industrial Training Simulation
In SprayPaint the application of liquid coatings in industrial paint booths is simulated, and the Polhemus FASTRAK is used to report the position and orientation of a spray gun mockup as the user moves it to control the virtual gun in the life-sized computer-generated paint booth.
The Johnson Center for Virtual Reality was established in 1999 as a service and development center of Pine Technical College, a unit of Minnesota State Colleges and Universities. Its mission is to encourage and support the use of computer simulation to improve education and training. Several industrial training simulations have been created for regional industries, including SprayPaint and QualityInspection, and several others are in development.
"To give the trainee users a realistic experience, we knew we would have to provide a natural way for them to interact with and control things in the 3D virtual environment," said John Heckman, Director, Johnson Center VR. "The real-time positioning information from Polhemus FASTRAK® has proven to be the key."
"We tried other motion tracking products but chose Polhemus FASTRAK for its accuracy and reasonable price," states Heckman. "We had to write drivers for applications and found Polhemus technical support and examples to be helpful."
In SprayPaint, for example, the application of liquid coatings in industrial paint booths is simulated, and the Polhemus FASTRAK is used to report the position and orientation of a spray gun mockup as the user moves it to control the virtual gun in the life-sized computer-generated paint booth. The Polhemus FASTRAK data stream allows mathematical modeling of where and how the virtual paint hits the paintable objects found in the simulation. In some versions, a head-mounted Polhemus FASTRAK receiver also controls the user's point-of-view.
In other simulations the Polhemus FASTRAK allows users to control virtual tools and objects without having to learn a keyboard interface. As a result, simulations can mimic workplace actions and behaviors in very believable and effective ways.