Contrast Stretching Recursively Separated Histogram Equalization for Brightness Preservation and Contrast Enhancement

Contrast enhancement of an image can efficiently performed by histogram equalization. However, this method tends to introduce unnecessary visual deterioration such as saturation effect. One of the solutions to overcome this weakness is by preserving the mean brightness of the input image inside the output image. This paper proposes a new histogram equalization method called contrast stretching recursively separated histogram equalization (CSRSHE), for brightness preservation and image contrast enhancement. This algorithm applies a two stage approach: 1) A new intensity is assigned to each pixel according to an adaptive transfer function that is designed on the basis of the global and local statistics of the input image. 2) Performing recursive mean separate histogram equalization based on a modified local contrast stretching manipulation. We show that compared to other existent methods, CSRSHE preserves the image brightness more accurately and produces images with better contrast enhancement.