EXTRACTING OBJECT MOTION DURING OBSERVER MOTION - COMBINING CONSTRAINTS FROM OPTIC FLOW AND BINOCULAR DISPARITY

Detection of object motion by moving observers and perception of veloc ity by stationary or moving observers ordinarily require information a bout object distance. It might be expected that object motion could be obtained without distance by use of a combination of optic flow and b inocular disparity information. We describe how object motion could, i n principle, be derived this way. The analysis also permits recovery o f target distance. Finally, information about the observer's motion ma y be obtained in a similar fashion, assuming the existence of two stat ionary environmental points at an unknown distance. Although studies o f human observers have not been completed, it appears that these infor mational variables are available under conditions in which observers p erform well at detecting motion and stability. In particular, the info rmation may help to explain why a visible surface in near space facili tates accurate perception.