Abstract: Image enhancement is a process of improving the quality of the image by improving its features. Contrast enhancement is one of the challenging and interesting areas of image processing. In visual perception of the real world, contrast is determined by the difference in the colour and brightness of the object and other objects within the same field of view. The commonly used techniques for contrast enhancement fall into two categories:(1) indirect methods and (2) direct methods. Indirect approaches mainly modify histogram by assigning new values to the original intensity levels. Direct contrast enhancement method establishes a criterion of contrast measurement and enhancesthe image by improving the contrast measure. In this paper, we propose a fuzzy contrast enhancement method employing both direct and indirect methods.

Keywords: Fuzzy logic, Defuzzification, Histogram, Contrast improvement index.