Abstract: Histogram equalization (HE) or projection is the well known method for the image enhancement because of its simplicity and is the base for advanced algorithms. Mainly there are two branches: global and local HE. In the global histogram equalization the entire image is equalized at a stretch where as in local histogram equalization the image is divided into sub-blocks and HE is carried for each block. In this paper, the image is segmented first. Number of sub-block is based on size of image and also sub-blocks are taken such that they are not overlapped. Then HP is done individually on each sub-block following this each sub-block is related to three of its adjacent sub-blocks by certain weight. This is to enhance the local details as well as to overcome the blocking effect. The algorithm is implemented using MATLAB and from results it can be shown that it enhances the image without any blocking effects also local details are enhanced. So it well suits for consumer electronics.

Keywords: Histogram equalization, Contrast enhancement, Local histogram equalization.