Auxiliary functions and optimal scanning for road detection by dynamic programming

Shape information is useful for road detection to improve the correctness and smoothness of the results. Within the frame of dynamic programming, the proposed method stores in an auxiliary image the global direction V(M) followed in the current shortest path. The potential is a function of this image, so that pixels prolongating the current shortest path are favored. The auxiliary image is updated recursively at the same time as the energy, during the optimization. A variant of this method stores in the auxiliary image the center of the circle tangent to the current shortest path. Another application presented herein computes the average of the potential instead of its sum. The optimality principle is not verified anymore with the auxiliary functions but they give smoother results without increasing the complexity. Furthermore, several improvements w.r.t. the scanning allow gains of up to 50% for the computational time.