Dynamic Stereo in Visual Navigation

Visual processing is very important for robot navigation. It has been demonstrated that many complex operations, which deserve an intelligent behaviour, can be performed relying only on reflexes to visual stimuli. In this framework the detection of corridors of free space along the robot trajectory is certainly a very important capability to safely navigate. Stereo vision and motion parallax can be used as cues to infer scene structure and determine free space areas. In this paper we propose a cooperative schema in which binocular disparity, computed on several stereo images over time, is combined with optical flow from the same sequence to obtain a relativedepth map of the scene. Both time-to-impact and depth scaled by the distance of the camera from the fixation point in space are considered as good, relative measurements which are based on the viewer (but centered on the environment). Simple relations are defined which combine disparity and optical flow for relative-depth estimates...