So as to build sharp one histogram (or multiple histograms), some improvements are proposed, i.e., various accurate prediction and interpolation approaches [19]–[31] to build sharp histogram, sorting and selection scheme [19]–[30] to choose those pixels in the smooth regions for building sharp sub-histogram, and recent multiple histograms based schemes [32]–[35] to construct several tight/sharp sub-histograms according to their texture similarity.