Visually Lossless Accuracy of Motion Vector in Overcomplete Wavelet-based Scalable Video Coding

In this paper, we propose a visually lossless accuracy model for scalable coding of motion vectors in overcomplete wavelet-based scalable video codec. By exploiting theory of stationary random process, we first estimate motion compensation errors in spatial domain due to inaccurate motion vectors. We then extend the results to overcomplete wavelet domain, and further derive the errors caused by fraction-pixel motion vectors. Finally, combining with a visibility model of wavelet coefficient errors, we propose a novel algorithm to estimate the accuracy threshold of motion vectors with which motion compensation errors will be invisible. Experimental results show that our algorithm is effective in estimating visually lossless accuracy threshold of motion vectors. The proposed algorithm can also be used in scalable motion estimation in wavelet domain. It can accelerate motion estimation speed by stopping halfway at the accuracy that will not cause any visible errors.