METHOD FOR EVALUATING THE DEGRADATION OF A VIDEO IMAGE INTRODUCED BY A DIGITAL TRANSMISSION AND/OR STORAGE AND/OR CODING SYSTEM

The invention concerns a method for assessing the degradation of a video image coded by blocks of picture elements or pixels, comprising the following steps: a) selecting an input image and determining its spatial activity (SA) in an analysis window according to the following sub-steps: i) determining for each block (n, m) the transformed coefficients Fn m (i, y) by a block transform; ii) determining from the transformed coefficients Fn, m (i, y) each block spatial activity bsa; iii) determining the analysis window global spatial activity SA1; b) selecting the output image corresponding to the input image and determining said global spatial activity SA2 of the output image; c) comparing the spatial activities (SA2) and (SA1)