Matching Pursuit Dictionary Pruning for MPEG-4 Video Object Coding

This paper describes how Matching Pursuit can be employed in an MPEG-4 video encoder as a replacement for the DCT at boundary-blocks to improve coding efficiency, while retaining backward compatibility. The key aspect of Matching Pursuit is that the video signal can be represented with less coefficients than with an orthogonal transform, due to the over-complete set of basis functions. However, Matching Pursuit cannot be integrated in a straightforward way into an existing encoder framework without loss of coding performance. Therefore, we modify the Matching Pursuit algorithm to increase the compression efficiency by a newly developed dictionary pruning scheme. Experimental results show that it can improve the obtained PSNR by up to 1 dB at object boundaries when compared to the basic Matching Pursuit.