A Fast Approach for No-Reference Image Sharpness Assessment Based on Maximum Local Variation

This letter proposes a simple and fast approach for no-reference image sharpness quality assessment. In this proposal, we define the maximum local variation (MLV) of each pixel as the maximum intensity variation of the pixel with respect to its 8-neighbors. The MLV distribution of the pixels is an indicative of sharpness. We use standard deviation of the MLV distribution as a feature to measure sharpness. Since high variations in the pixel intensities is a better indicator of the sharpness than low variations, the MLV of the pixels are subjected to a weighting scheme in such a way that heavier weights are assigned to greater MLVs to make the tail end of MLV distribution thicker. The weighting leads to an improvement of the MLV distribution to be more discriminative for different blur degrees. Finally, the standard deviation of the weighted MLV distribution is used as a metric to measure sharpness. The proposed approach has a very low computational complexity and the performance analysis shows that our approach outperforms the state-of-the-art techniques in terms of correlation with human vision system on several commonly used databases.