Abstract: Face recognition under different illumination conditions is one of the challenging problems in pattern recognition field.In this paper,a pre-processing technique based on Region Regulation Model (RRM) is proposed.It divides a face image into four parts,and in each part a linear transformation point-by-point is conducted.The technique is feasible,simple and tractable in computing.Moreover,it is very effective to weaken the aftereffect of varying illumination.Comparing with the popular techniques,such as Histogram Equalization (HE) and Region-based Histogram Equalization (RHE),experiments are performed on Yale B face image database.The results illustrate that this pre-processing technique is available and efficient.

Key words: illumination variation, histogram equalization, region-based histogram equalization, image regulation, face recognition