Image contrast enhancement based on histogram equalization of sub-image

Аннотация

Image contrast enhancement purposely aim the visibility of image to be increased. One of the common methods used for improving contrast in digital images is Histogram equalization (HE). This paper presents a method to enhance the contrast of an image by applying histogram equalization to a part of the image. The image is partitioned into two parts based on the pixel intensities with respect to the median intensity. Histogram equalization is applied to either one of the two parts while keeping the other part unchanged as in the image. Applying histogram equalization to one part of the image, in which the peak intensity is involved, generates higher contrast image than applying histogram equalization to the entire image. Experimental results based on qualitative and quantitative evaluation have demonstrated that the proposed method is able to increase the brightness of an input image.