Measuring blockiness in decoded video images

摘要

An apparatus and method for determining the degree of blockiness in decoded video images is disclosed. A Fourier transform of the decoded video image or an image derived from a decoded video image is generated. Components of the Fourier transform characteristic of block edges in the decoded image are identified. The energy of at least one of the identified components is measured, and the measured energy of the or each identified component is compared with the total energy within the Fourier transform. The comparison is indicative of the degree of blockiness in the decoded image prior to generation of the Fourier transform, and can be used to predict an objective degree of blockiness with improved accuracy. By filtering in the frequency, rather than the spatial domain, the block edges within the decoded image are isolated from the remaining information within the decoded image with significantly more accuracy than previously.