Adaptive Region-Based Image Enhancement Method for Face Recognition Under Varying Illumination Conditions

Illumination changes in face images form a main obstacle in face recognition systems. To deal with this problem, this study presents a novel adaptive region-based image preprocessing scheme that enhances face images and facilitates the face recognition task. This method enhances both the edges and the contrast in face images regionally so as to alleviate the side lighting effects. Compared with the conventional global histogram equalization method, our method is shown to be more suitable for dealing with uneven illuminations in face images. This method is evaluated on the Yale B face database. The experimental results show the advantages of the proposed method with an improvement of 16.1% on average over the histogram equalization method