Different Presentations of 3D Objects
Hanqiu Sun, Kwong Wai Chen, Pheng Ann Heng
Dept. of Computer Science & Engineering, The Chinese University of Hong Kong
To achieve high-level realism of virtual reality (VR) system, the virtual environment should reproduce sufficient depth cues the same as human's perception in the real world. These include stereopsis, perspective, occlusion, shadows, texture and the like. Conventional graphics workstations can realize some of the depth cues such as occlusion, perspective, lighting and shade, atmospheric effect (e.g. fog). More sophisticated VR system can also render binocular disparity, motion parallax, interposition, and convergence. A virtual reality application, however, should provide high refresh rate so the user can interact with the application in real time. To achieve high frame rate, the application should be tuned and optimized for real-time performance. It is usually better to reproduce more depth cues, but it can take the computer with limited resource more time to render and thus degrade the performance. For instance, stereoscopic vision requires two display channels to be rendered in a frame interval. Since humans have only limited vision, more details may be at times unnecessary. It is important to found out what depth cues are really required and what can be ignored if a high frame rate is to be achieved.
In this project, we investigated how the depth perception is affected by different representations of 3D objects in static virtual scenes. We studied depth cues in human's perception, human stereo viewing, and stereo-graphics VR system (hardware & software components). Based on the study, a set of experimental trials was designed and conducted to evaluate the factors that may influence a subject's ability to estimate the depth of objects in a static scene. The experiments also measured how advanced rendering is really needed when presenting 3D objects in static virtual scenes.
Many authors in the literature have discussed general issues on depth perception. There are, however, few specific studies in the computer graphics