Contrast Improvement using Local Gamma Correction

Abstract

This paper represents a local Gamma-correction technique that tries to supplement the limitations of the conventional Gamma-correction scheme. Gamma correction is a widely used contrast manipulation scheme which is broadly employed in many image enhancement applications. However, this technique is able to enhance a particular range of intensity levels and simultaneously fails to enhance the other intensity regions in an image. An image with different grades of intensity regions can't be enhanced simultaneously using a single gamma value. To overcome this problem, an adaptive local gamma correction technique is proposed here. In this method, the gamma factor is varied locally according to the local mean intensity of a neighborhood. As a result, the local gamma values corresponding to the different grades of intensity range would be different resulting in effective contrast manipulation of an image. This results in contrast improvement of different image regions of dissimilar grade of intensity range. Simulation results reveal that the proposed technique subjectively provides superior performance than many of the existing image enhancement schemes.