A histogram equalization model for color image contrast enhancement

The main aim of this paper is to develop a histogram equalization algorithm for color image contrast enhancement. Our idea is to propose a variational approach containing an energy functional to determine local transformations in the lightness (L) and chroma (C) channels of the CIE LCH color space such that the histograms in these two channels can be redistributed locally. In order to minimize the differences among the local transformation at the nearby pixel locations in each channel, the spatial regularization of the transformation is incorporated in the functional for the equalization process. The existence and uniqueness of the minimizer of the variational model can be shown. Experimental results are reported to show that the performance of the proposed models is competitive with the other compared methods for several testing images.