New technology on stereo vision for mobile robots

A stereo vision system is presented. Having felt strongly the necessity of providing robots with a visual system, the authors have first developed a visual sensing system for obstacle detection. Experiments to detect obstacles are shown. The visual system used in the experiments is LDM (laminated difference method) system, an entirely new technology, for internal processing, although having the same hardware construction as that of conventional stereo visions. LDM is based on the comparison in brightness between picture elements to avoid occlusion problem and to achieve high-speed processing. Using a heuristic method to find solutions that satisfy the geometrical conditions in three-dimensional space in detecting the corresponding points in stereo pictures, it reduces the vagueness resulting from correspondence processing between picture elements. The visual sensing system uses 10 MHz NEC PC PASCAL and requires 1.7 sec for scanning 256 horizontal directions (one scanning line) from the fetching of a picture to depth measurement in the directions of the field of view.<>