Contrast enhancement is considered as one of the critical trademark in the field of image processing and histogram equalization is a straightforward and understood strategy for image contrast upgrade, this technique utilizes the histogram of image in its preparing. In spite of the fact that the ordinary histogram equalization technique is broadly acknowledged however this strategy experiences the drawback of “mean-shift” issue, i.e. mean brightness of processed image will always be the middle gray level regardless the mean brightness of the input image. So it is not considered as the best technique for balance improvement with brightness protection. A few other histogram equalization based techniques have been introduced to overcome the issue of mean shift problem. In this paper we will survey generally utilized histogram equalization strategies utilized for differentiation upgrade and brightness conservation.
Keywords: – histogram equalization, contrast enhancement, brightness preservation.
Rajshree Singh, Brajesh Patel