Optical tracking of head and device of multiple users formed an important and integral component of the research done in the IMVIS FP7 project.
The IMVIS (2008-2011)FP7 project description
The IMVIS project carried out research to develop novel projection-based stereoscopic multi-view systems for co-located collaborative 3D displays for multiple users. The use of PS-Tech's optical tracking technology played an important role to enable the interaction between multiple users.
Optical tracking of head and device of multiple users
The physical effects of geometric manipulations must match the corresponding activities from the physical artefacts. These physical artefacts or input devices provide intuitive usability but also mutual awareness in co-located collaborative work, when properly designed in shape and appearance. Then, the flow of interaction with the system, through the optical tracking of head and device of multiple users, becomes understandable by observing the operators actions.
PS-Tech’s multi-user optical tracking
PS-Tech developed a multi-user optical tracking system, with its available technology, to enable multiple users to interact with a projection based multi-view system.
The optical tracking goals for IMVIS are summarized below:
- Expansion of a single user tracking system to multi-sensor tracking,
- Resolving the problem of occlusion,
- Wide area coverage,
- Integration and synchronization of multiple tracking units,
- Integration of the synchronization of multiple shutter glasses of the users,
- Tracking Targets : 20,
- Tracking Volume [m x m x m]: 5x3x2,
- Tracking Rate/Latency [Hz]/[ms]: 50/33,
- Tracking Accuracy [mm]/[Â°]: 5/1.
The experiences from the IMVIS project resulted in the optical trackers PST 55 and PST 110.
The PST 55/110 optical tracking system
There are many different systems for optical tracking on the market. For the IMVIS project, a new approach was taken which resulted in affordable systems with a unique price-performance ratio. The PST 55 and PST 110 have resulted from the project with price points that are below that of competing systems while maintaining similar performance (accuracy/speed).
The PST 55/110 performs all processing internally. Most existing systems supply a set of cameras and require the use of a separate computer to perform the actual tracking. This puts a large load on the client system, slowing down other applications, on which simulations and rendering may also be taking place. The PST 55/110 only requires a small program on a user’s computer to communicate with the tracking unit, resulting in a very small impact on a system’s resources.
The PST 55/110 is a fully integrated unit that requires no complicated calibration procedures. Most existing systems use separate cameras and need to be calibrated as soon as a camera is moved (which can happen involuntarily due to small vibrations in the setup for example). As a result the PST 55/110 is easier to maintain, move or setup in another environment.
The PST 55/110 has a far greater flexibility in the type of rigid bodies it can track. Many existing systems only work with spherical markers and support only a small number of markers per body. Although this is also supported by the PST 55/110, flat markers can also be used and attached to any type of object. For instance, a toy car or coffee cup could be equipped with flat markers. This enables a user to manipulate such objects as he would do normally, unhampered by sticks with spherical markers.