Interactive viewpoint control and three-dimensional operations

Techniques are discussed for creating a rendered view into a 3D scene, interactively based on the locations and orientations of the observer’s head and the display surface. Stereoscopic headmounted displays (HMDs) demonstrate a simplified, special case of these techniques, because the eyes and monitors move in unison. A largely overlooked class of interactive displays uses the relative positions between the eyes and monitor as input. These displays can be stereo or monoscopic, fixed or mobile, and the rendering process should incorporate the correct perspective distortion, which depends on the locations of the viewpoint(s) and the display monitor. Three real-time graphics display systems were prototyped and examined: a high-resolution display which corrects the perspective projection based on the location of the observer’s eye; the same display, extended to modify the view as the monitor is tilted and swiveled; and a handheid LCD display which can be freely moved and rotated as it displays a view based on the eye and monitor positions. A simple experiment indicates that tracking the head and providing the appropriate view improves the ability to pick specific 3D locations in space using a 2D display, when compared to a fixed view and a mouse-controlled view.