Image preprocessing techniques for illumination-invariant face recognition based on Self Quotient Images

SQI method has been proven to be an efficient image preprocessing technique for illumination-invariant face recognition. In this paper, we propose to apply smoothing and Contrast Limited Adaptive Histogram Equalization before SQI method. The motivation is to conquer the suppress noise that may hinder recognition task and enhance sharp edges in low frequency illumination parts which is beyond the capability of SQI.