The use of optical flow for the autonomous navigation

This paper describes the analysis of image sequences taken by a T.V. camera mounted on a car moving in usual outdoor sceneries. Because of the presence of shocks and vibrations during the image acquisition, the numerical computation of temporal derivatives is very noisy and therefore differential techniques to compute the optical flow do not provide adequate results. By using correlation based techniques and by correcting the optical flows for shocks and vibrations, it is possible to obtain useful sequences of optical flows. From these optical flows it is possible to estimate the egomotion and to obtain information on the absolute velocity, angular velocity and radius of curvature of the moving vehicle. These results suggest that the optical flow can be successfully used by a vision system for assisting a driver in a vehicle moving in usual outdoor streets and motorways