ACTIVE VISION FOR RELIABLE RANGING - COOPERATING FOCUS, STEREO, AND VERGENCE

This article addresses the problem of measuring reliabily the absolute three-dimensional position of objects in an unknown and cluttered scene. It circumvents the limitations of a single sensor or single algorithm by using several range recovery techniques together, so that they cooperate in visual behaviors similar to those exhibited by the human visual system. Implemented visual behaviors include (i) aperture adjustment to vary depth of field and contrast, (ii) focus ranging followed by fixation, (iii) stereo ranging followed by focus ranging, and (iv) focus ranging followed by disparity prediction followed by focus ranging. The main contribution is a demonstration that two particular visual ranging processes-focusing and stereo-can cooperate to improve measurement reliability. The results of 75 experiments processing close to 3000 different object points lying at distances between 1 and 3 meters demonstrate that the computed range values are highly reliable.