3-D redundant DCT restoration method for MPEG-compressed video

When a video sequence is compressed by the MPEG encoder with a low coding rate, various artifacts such as blocking artifacts are produced. To remove the artifacts, this paper proposes a video restoration approach with the 3-D redundant DCT, which utilizes spatiotemporal correlations of a moving image sequence more effectually than the 3-D orthogonal DCT. The approach recovers an image sequence by applying the shrinkage operation to 3-D DCT coefficients of the recovered sequence with the imposition of the MPEG-quantization constraint, an expansion of the JPEG-quantization constraint. Experimental simulations demonstrate that the approach successfully removes the compression artifacts selectively and improves subjective quality considerably.