Modified unsharp masking detection using Otsu thresholding and Gray code

In order to improve image quality, unsharp masking (USM) is a great solution for image enhancement. To detect USM sharpening, we propose an improved method called edge perpendicular Gray coding (EPGC). With EPGC, the number of feature points generated from binary encoding can be reduced to half and thus the execution of calculating histogram can be accelerated. In addition, we use Otsu thresholding to enhance Canny edge detection. As a result, the accuracy of USM detection is increased. Experimental results show that EPGC performs better than previous methods.