The capability of a moving autonomous vehicle to predict the motion of other objects based on their apparent motion in its field of view. Put in very simple terms: if a robot moves, any stationary objects will appear to move in the opposite direction t the same speed. However, another moving object will appear to move differently. An autonomous robot must deduce the direction and speed of other moving objects, also taking into account depth and its own motion. Optical flow, of course, requires camera input.