Histogram Equalization-A Simple but Efficient Technique for Image Enhancement

Abstract

This paper demonstrates the significance of histogram processing of an image particu larly the histogram equalization (HE). It is one of the widely used image enhancement technique. It has become a popular technique for contrast enhancement because the method is simple and effect ive. The basic idea of HE is to re-map the gray levels of an image. Here we propose two different techniques of Histogram Equalizat ion namely, the global HE and local HE. The Histogram Equalization has been performed in the MATLA B environ ment. The merits and demerits of both techniques of Histogram Equalization have also been discussed. It is seen after exhaustive experimentation on a nu mber of sample images that the proposed image enhancement techniques can be considered as an imp rovement over the inbuilt MATLAB function histeq.