An efficient contrast enhancement method using repulsive force of edges

This paper presents a novel algorithm which employs edge information to automatically improve the quality of low contrast images. This algorithm finds and thins the edges of an input image and then assigns a controlled repulsive force to each of them. The gray levels of the image are shifted to new values based on the force of all edges. Some shifted gray levels may overflow the gray-scale interval (0–255), therefore they are returned back into the original interval by using a new transfer function. This transfer function preserves the details of the input image as much as possible while enhancing its contrast. Finally, the intensity of each pixel in the input image is mapped into its corresponding output value to obtain the enhanced image. Experimental results reveal that the proposed algorithm has the best performance compared to the other methods evaluated considering preservation of image details while enhancing its contrast.