Method and apparatus for measuring blockiness in video images

摘要

The present invention relates to an apparatus and method for processing images, in particular for determining the degree of blockiness in coded images. The invention comprises apparatus and methods for determining a degree of blockiness by performing the steps of: for each of a plurality of pixels determining a vertical gradient measure in dependence upon the values of said pixel and neighbouring pixels; comparing said vertical gradient measure with a vertical gradient threshold and defining said pixel as a potential horizontal boundary in dependence thereon determining a horizontal gradient measure in dependence upon the values of said pixel and neighbouring pixels; comparing said horizontal gradient measure with a horizontal gradient threshold and defining said pixel as a potential vertical boundary in dependence thereon; and determining said blocking artefact measure in dependence upon the vertical gradient measure of pixels defined as a potential horizontal boundary and upon the horizontal gradient measure of pixels defined as a potential vertical boundary. Method and apparatus for generating a quality measure in dependence upon the measure of blockiness are also provided.