An approach to obstacle detection and steering control from optical flow

In this work an approach to obstacle detection and steering control for safe car driving is presented. It is based on the evaluation of 3D motion and structure parameters from optical flow through the analysis of image sequences acquired by a TV camera mounted on a vehicle moving along usual city roads, countryroads or motorways. This work founds on the observation that if a camera is appropriately mounted on a vehicle which moves on a planar surface, the problem of motion and structure recovery from optical flow becomes linear and local, and depends on only two parameters: the angular velocity around an axis orthogonal to the planar surface, and the ratio between the viewed depth and the translational speed, i.e. the generalized time-to-collision. Examples of the detection of moving surrounding cars and of the trajectory recovery algorithm on image sequences of traffic scenes from urban roads are provided.