The MSRR Augmented Reality system

Our AR system is shown in the figure below - basically two stereo image streams are combined and presented to the user. One image stream (the 3D computer graphics) is generated by an Intergraph TDZ2000, and the other is captured from teh remote environemnt by a stereo robotic head system mounted on a mobile vehicle. A 3D model of the real world can be developed off-line on the Intergraph using 3dStudioMax, then imported into and manipulated in real time using World Toolkit software. The combination of the image streams (PAL from the stereo head cameras and VGA from the Intergraph) is achieved using luma-keying devices. Two systems for viewing the stereo mixed video are available - a Virtual Research V8 HMD and a 21" stereo monitor from Stereographics.

The head and vehicle controller is based around a PMAC multi-axis motion controller from Delta Tau Inc . The PMAC card performs initialization, calibration, PID-parameter tuning and runtime control functions. A host PC, running Windows NT, provides the interface between the head tracking system (currently either a Polhemus Fastrak or an Intersense IS-300 device) and the servo positioning system by interpreting the trajectory data from the input sensor and translating this information into a suitable format to present to the PMAC closed loop control system. The encoder readings of the pan and tilt axes, stored in registers on the PMAC device, can be copied in real time to an area of dual ported RAM for access by the host PC.

Communications between the Intergraph system and the head/vehicle controller are implemented using a 100Mbit Ethernet link. The World Toolkit program running on the Intergraph can request an update of the position of the stereo head and the vehicle between each rendering operation via this socket connection. This sockets link does not degrade the performance of the graphics system and a frame rate of 35 frames per second is achievable.

MSRR people involved with the development of this system are Shaun Lawson, Vincent Valdy, John Pretove , and Alison Wheeler.

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These pages are administered by Maarten Michielen (m.michielen@surrey.ac.uk)
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Last change: April 2000