A Survey on Image Contrast Enhancement

Image Contrast enhancement without affecting other parameters of an image is one of the challenging tasks in image processing. The quality of poor images can be improved using various Image Contrast Enhancement techniques. Contrast is the visual difference that makes an object distinguishable from background. This paper presents the comparative study of some popular image contrast enhancement techniques such as histogram equalization, Brightness preserving bi-histogram equalization, Dualistic Sub image Histogram Equalization, Recursive Mean Separate Histogram Equalization and Minimum Mean Brightness Error Bi-histogram Equalization. Bi-histogram equalization preserves the original brightness to certain level. There are some cases that are not preserving well by Brightness Preserving Histogram Equalization as they require higher degree of preservation. Brightness Preserving Histogram Equalization referred to a Recursive Mean Separate Histogram Equalization to provide not only better but also scalable brightness preservation. Brightness preservation not handled well in Histogram Equalization, Brightness Preserving Histogram Equalization, and Dualistic Sub image Histogram Equalization but it is handled well in Recursive Mean Separate Histogram Equalization and Minimum Mean Bi-histogram Equalization