Bright region preserving back-light image enhancement using clipped histogram equalization

Abstract

This paper presents a back-light image enhancement method using modified histogram as an optimal intensity transfer function based on clipped histogram equalization. The proposed method separates and clips the input histogram according to the clipping rate computed by the mean brightness of an input image. Next, the clipped histogram bins are adaptively redistributed according to the shape of histogram in the bright region. Since the bright region of modified histogram has a uniform shape, the proposed method makes the cumulative distribution function be a linear function in the bright region of the histogram. The experimental results show that the proposed method enhances the contrast of dark region without saturation and over-enhancement in the bright region.