A virtual space video conferencing demonstration system

This report describes a system that was constructed to demonstrate and study the subjective effects of switching delay in a virtual space video conferencing system and presents some preliminary results of the subjective evaluations. The concept of virtual space video teleconferencing provides geographically separated participants with a visual environment that very closely simulates a meeting room where all participants are physically present. At each site, TV camera/monitor pairs representing the remote participants are located in front of the physically present participant in approximately the same positions as these participants would occupy if they were seated around a meeting table in the same room. The local participant can at any time choose which monitor (participant) he wishes to watch and, by the head and eye positions as seen on the monitors, he can determine where the other participants are looking as well. A virtual space conference consisting of N single participant sites would require (N x (N-1)) TV camera/monitor pairs, and presenting a continuous video signal to each monitor would require as many dedicated video channels. By taking advantage of the fact that a participant can view only one monitor at a time, and utilizing a transmission scheme which dynamically allocates a single incoming video channel to each site to carry the signal for the monitor currently in view, the total video channel requirement can be reduced significantly.