01/01/1994 09:00 AM
Computer Science
Intereactive stereoscopic images can be viewed on a graphics workstation by producing side-by-side images and viewing through a simple mirror device. However, it is important that the viewing device have pairs of adjustable nonparallel mirrors so large windows can be viewed without the human\'s sightlines needing to diverge, or ``look wall-eyed\". Trans- formations to produce the correct images for this viewing method are described. Previous work applied to the case where both left and right images were to be superimposed and multiplexed in the same region of the screen, often called anaglyphs. Such cases are adequately handled by a translation and an off-axis perspective transformation. The same kind of transformation can be used with a parallel-mirror device, but such devices have practical limitations. This paper shows that nonparallel mirrors require a somewhat more complicated transformation involving scene rotations as well. Derivation of the correct angle of rotation is the main difficulty in computing this transformation. The transformation can be implemented by a sequence of graphics library procedures. Advantages and disadvantages of nonparallel mirror methods are discussed.
