ABSTRACT Contrast enhancement is important and plays vital role in many applications. Histogram
equalization-based techniques are widely used techniques for contrast enhancement. However, it faces the
contrast over-stretching, which in return causes the loss of details and unnatural look to the target image.
To address this issue, this work presents a novel scheme for image contrast enhancement. The contribution of
the proposed scheme is twofold. First, the image can lose many important information when an image size is
decreased. For that, the image is transformed from spatial to wavelet domain so that the multi-resolution can
be achieved. Second, Gamma correction is a proven technique that produces natural look and preserves mean
brightness of an image with the choice of optimal gamma values. Here, Particle Swarm Optimization (PSO)
is utilized to select the optimal gamma values. In this study, an effective fitness function is proposed to
maximize the performance of PSO. Experimental findings show that the proposed approach improve the
image contrast up to a greater extent without introducing any artifacts.