Divergent stereo for robot navigation: learning from bees

A qualitative approach to visually guided navigation based on the computation of optical flow field is presented. The approach is based on the use of two cameras mounted on a mobile robot and with the optical axis directed in opposite directions, such that the two visual fields do not overlap (divergent stereo). Range computation is based on the computation of the apparent image speed on images acquired during the robot´s motion. An example of reflex-type control of motion, driven by differential estimation of the flow field measured by the two eyes, is presented. It is shown how a difficult task like navigating through a funneled corridor with obstacles is possible without the need for metric depth estimation