Multi Segment Histogram Equalization for Brightness Preserving Contrast Enhancement

Abstract

Histogram equalization (HE) method proved to be a simple and most effective technique for contrast enhancement of digital images, but it does not preserve the brightness and natural look of images. To overcome this problem, several Bi- and Multi-histogram equalization methods have been proposed. Among them, the Bi-HE methods significantly enhance the contrast and may preserve the brightness, but they destroy the natural look of the image. On the other hand, Multi-HE methods are proposed to maintain the natural look of image at the cost of either the brightness or its contrast. In this paper, we propose a Multi-HE method for contrast enhancement of natural images while preserving its brightness and natural look. The proposed method decomposes the histogram of an input image into multiple segments, and then HE is applied to each segment independently. Simulation results for several test images show that the proposed method enhances the contrast while preserving brightness and natural look of the images.KeywordsHistogram equalizationhistogram segmentationcontrast enhancementbrightness preserving