Adaptive Contrast Enhancement using Optimal Equalization of 2-Dimensional Histogram

In this paper, an adaptive image contrast enhancement algorithm based on an optimization problem in two dimensional histogram domain is presented. To reduce the unwanted effects of the histogram adjustment, through this optimization-similar to the other methods- the 2D histogram of enhanced image is found in close proximity to input image histogram and uniform distribution, simultaneously. In addition, different from the other methods, by adaptive adjusting the components of a weight matrix, local information is counted. Experimental results in the quantitative and qualitative assessments on a wide range of images demonstrate the performance of the proposed method. Tests have shown that with the addition of the adaptive adjusting the weights, the average performance in contrast enhancement increases 75 and 3 percent from the viewpoint of the AMBE_N and DE_N, respectively.