The ability to explore unknown spaces independently, safely and efficiently is one of the challenging aspects of any blind assisting system. Many of the known existing electronic travel aids do not reveal spatial information to the blind. Therefore in this paper the focus is on obtaining the spatial information with the help of image processing techniques. Different disparity estimation algorithms are studied in order to arrive at a scheme specifically suitable for the blind. Real time images are captured by a pair of image sensors and the proposed algorithm will determine the surface conditions such as curbs, stair case and other general obstacles encountered on the navigational path.