Patent ID: 6823009
Filing Date: 2004-11-23
Classification: H04N

Abstract:
A method of evaluating the degradation of a video image coded by blocks of pixels, this degradation being generated by a coding and/or storage and/or transmission system producing an output image on the basis of an input image, the method comprising:a) selecting an input image and determining a spatial activity of the input image in an analysis window representing at least one part of the image which exhibits a set of said blocks of pixels, this determination implementing the following sub-stages: i) determining, for each block of the said set of blocks of pixels, transformed coefficients via a block transform according to the blocks, ii) determining, on the basis of the transformed coefficients the spatial activity of each block of the set of blocks of pixels, and iii) determining, on the basis of the spatial activity of each block, the overall spatial activity of the set of the blocks of pixels constituting the analysis window b) selecting the output image corresponding to the input image and determining the said overall spatial activity of the output image in the analysis window, by implementing sub-stages a i) to a iii) for the output image; and c) comparing the overall spatial activity of the output image in the analysis window and the overall spatial activity of the input image in the analysis window.