An approach based on parametric sigmoid function for contrast enhancement with mean brightness preservation

Enhancing the contrast of a digital image without affecting the mean brightness of the input digital image is a basic requirement in many electronic applications. In this paper we proposed a contrast enhancement technique without affecting the mean brightness of the images. We propose a parametric sigmoid formula in which contrast and the position of steepest point of the curve of the function is adjusted by the parameters of sigmoid function. The experimental results show that we are able to enhance the contrast of the input image without making any significant effect on the mean brightness of the image.