Fast eye localization based on pixel differences

A novel fast eye localization algorithm based on pixel differences is presented, which is suitable for face recognition system on mobile device. It is based on the fact that eyeball is dark and round. A binary eye map is obtained by choosing those pixels darker than surrounding; then it is filtered by a rank order filter; connected regions in the eye map are then labeled by their geometric centers; best suitable eyeball pair is selected based on a set of geometric constraints. If no eyeball pair is detected, the algorithm is repeated iteratively until one pair is found. The algorithm is fast since it converts the gray level image to a binary eye map at the beginning. The algorithm is tested on our own face database, which consists of 4095 images of size 250×200. Detection rate is 93.04% when the tolerance is 0.7 times of eyeball width.