No-reference image sharpness Algorithm based on gradient shape

Abstract

Image sharpness is an important aspect of image quality. It used to measure the degree of focus at the time of image acquisition. It also play an important role for video compression. Here, one new sharpness algorithm based on gradient shape is introduced in this paper. which is used for no-reference Image .The algorithm gets region of Interest in image firstly, then search the edge which can present sharpness information in selected region . It calculates edge transition zone width, then gets gray contrast in edge region, finally a probability summation algorithm model be set by these factors. This algorithm can calculate the sharpness degree of different images. A lot of experimental results show that this sharpness algorithm is effective and keep consistency with human subjective judgment. It can be used to describe the no-reference image sharpness effectively.