Contrast enhancement based on divided histogram manipulation

A novel histogram manipulation technique, which re-assigns pixels of three sub-images based on a divided histogram, is presented. We use k-means to obtain two cluster centroids from the input image histogram, and then two thresholds are deduced to divide the input image into three sub-images. After mathematical morphology, connected components are obtained from sub-images separately. The proposed novel histogram manipulation technique applies, separately, histogram equalization to the three sub-images that were obtained by decomposing the input image based on two thresholds in the original histogram.