Histogram Equalization Based Image Contrast Enhancement Techniques-Review

Image enhancement is one of the challenging issues in digital image processing. Contrast enhancement techniques are used for improving visual quality of low contrast images. Histogram Equalization (HE) is one of the common methods used for improving contrast in digital images. As a result, such image creates side-effects such as washed out appearance and false contouring due to the significant change in brightness. In order to overcome these problems, mean brightness preserving HE based techniques have been proposed. Generally, these methods partition the histogram of the original image into sub histograms and then independently equalize each sub histogram with Histogram Equalization. This paper presents a review of recent histogram based techniques for still image contrast enhancement. Comparisons with the best available results are given in order to illustrate the best possible technique that can be used as powerful image enhancement.