Low-Band-Shifted Hierarchical Backward Motion Estimation, Compensation for Wavelet-Based Video Coding.
Yufei Yuan, Mrinal Kr. Mandal · Indian Conference on Computer Vision, Graphics and Image Processing · 2002
A new framework for block-based backward motion compensation in wavelet scalable video coding scheme is proposed. Motion estimation and compensation are hierarchically conducted in wavelet domain using coarser level lowpass subband in the current frame and synthesized next finer level lowpass subband in the reference frame, hence, the motion information does not need to be transmitted. To alleviate the aliasing effect caused by decimation in wavelet decomposition, the lowpass subband in reference frame are shifted to obtain four subbands, which are then used in motion estimation and compensation to generate final prediction. A flexible quantization scheme and arithmetic coding is used to individually encode the motion compensated subbands without exploiting cross-band correlation. Compared to the motion estimation and compensation scheme without shifting of the lowpass subband, the proposed technique provides around 2 dB improvement in PSNR for compression of full motion sequence. The multi-level scalability of the scheme makes it useful for low bandwidth networks, such as satellite or cellular networks.