The Trinocular General Support Algorithm: A Three-camera Stereo Algorithm For Overcoming Binocular Matching Errors

The combined use of binocular and new trinocular matching constraints in the Trinocular General Support Algorithm's (TGSA) parallel relaxation computation is shown to overcome many of the problems in binocular sterm matching. These problems include: (I) ambiguity in matching in periodic regions, especially when such a region is partially-occluded, (2) erroneous matches near occluded regions, and (3) missing and erronwus matches due to significant structural variations between the images. The TGSA employs cameras positioned at the vertices of an isosceles right triangle. Matching takes place between the horizontally-aligned pair of images and the vertically-aligned pair of images. Along with a variety of binocular constraints, new trinocular constraints, called trinocular uniqueness and the trinocular disparity gradient, are used to relate vertical and horizontal matches. When combined using a connectionist network relaxation algorithm, these constraints help to overcome the binocular matching problems listed above. For example, the trinocular disparity gradient provides enough information to directly resolve ambiguity in periodic regions in many cases. The TGSA has been tested on a number of image triples to demonstrate its advantages over previous binocular and trinocular stereo matching algorithms.