Image dependent brightness preserving histogram equalization

Abstract

This paper proposes image-dependent brightness preserving histogram equalization (IDBPHE) technique to enhance image contrast while preserving image brightness. The curvelet transform and histogram matching technique are used to enhance image. The proposed IDBPHE technique undergoes two steps. (i) The curvelet transform is used to identify bright regions of the original image. (ii) Histogram of the original image is modified with respect to a histogram of the identified regions. Histogram of the original image is modified using a histogram of portion of the same image hence, it enhances image contrast while preserving image brightness without any undesired artifacts. A subjective assessment to compare the visual quality of the images is carried out. Absolute mean brightness error (AMBE) and peak signal to noise ratio (PSNR) are used to evaluate the effectiveness of the proposed method in the objective sense. The proposed method have been tested using several images and gives better visual quality and PSNR value as compared to several other methods.