Patent ID: 8335401
Filing Date: 2012-12-18
Classification: H04N

Abstract:
1. A system for measuring blocking artifacts in a digital image, the digital image being divided into a plurality of blocks and having luminance components and chrominance components, the system comprising: at least one memory; and at least one processor operative to execute at least one computer program out of the at least one memory: to generate, from one of the luminance and chrominance components of the digital image, image pixel data in an image pixel array corresponding to the digital image, the image pixel array having a plurality of pixel locations for pixel values of the image pixel data; to calculate gradient image data in a gradient image array from the image pixel data, the gradient image array containing a plurality of gradient values of the gradient image data, each of the plurality of gradient values corresponding to a respective gradient value calculated in a specified direction for a respective pair of adjacent pixel locations in the image pixel array; to calculate normalized gradient image data in a normalized gradient image array from the plurality of gradient values contained in the gradient image array, the normalized gradient image array containing a plurality of normalized gradient values of the normalized gradient image data; to generate profile data by accumulating the plurality of normalized gradient values contained in the normalized gradient image array with reference to the specified direction; to apply a 1-dimensional (1-D) discrete Fourier transform (DFT) to the profile data to generate a plurality of DFT coefficients; to establish a range of block size values for the plurality of blocks in the specified direction; for each block size value, to generate an initial measurement of blocking artifacts in the digital image from peak magnitudes of the DFT coefficients, thereby obtaining a plurality of initial blocking artifact measurements; to designate a maximum one of the plurality of initial blocking artifact measurements as a final measurement of blocking artifacts in the digital image; and to generate an output indicative of the final measurement of blocking artifacts in the digital image.