Computer Software and Hardware Platforms

The presence measure experiment of Chapter 4 made use of a standard PC and ``Virtual TV'' (VTV) software from Warp, Ltd. [1] which allows a very large image to be stored in memory. The VTV software ``precomput[es] the rendering of a scene from all possible view orientations. This permits unlimited pan/tilt/roll/zoom freedom at high framerates on standard VGA cards.'' [107] Instead of dynamically computing updates to the visual scene, oscillations were implemented more efficiently by indexing into different portions of the image. This allowed for a frame-rate of 60 Hz. Unfortunately, it also meant that the scene could not be displayed in stereo: the same indexed image was sent to both eyes of the HMD. To keep the frame-rate consistently at 60 Hz in all conditions, an ``approximate dewarp'' mode was used, which does not precisely simulate oscillations around a fixed center-point. For the same reason, a rather low resolution of 240x320 pixels was used.

The reported presence/foreground occlusion research reported in Chapter 5 made use of the Division ProVision 100. The ProVision 100 is a hardware/software platform designed specifically for supporting virtual environments. It combines an Intel 486 platform with dedicated stereo graphics, three-dimensional audio, and low-latency virtual world interactivity in a single chassis. It can be accessed by standard UNIX applications. It comes with dVS, Division's software environment, which provides a distributed foundation for applications and a high level object-oriented programming interface. It is used in conjunction with the Division dVisor HMD described below.

The environment used for the research described in Chapter 5 was ``SharkWorld''. ``SharkWorld'' was developed by Division, Ltd. and features a texture-mapped underwater scene with a sunken ship and various moving sea creatures. The participants tried to catch sharks using a virtual net which followed real hand position.

The research involving control reversals (see Appendix C) made use of images generated by a Silicon Graphics Reality Engine II and displayed on a Silicon Graphics 20'' monitor.

Human Interface Technology Lab

Human Interface Technology Lab