Hsiang Shih-Ta, Woods John W, Ohm Jens-Rainer
Electrical, Computer, and Systems Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA.
IEEE Trans Image Process. 2004 Aug;13(8):1018-28. doi: 10.1109/tip.2004.828421.
Three-dimensional (3-D) subband/wavelet coding with motion compensation has been demonstrated to be an efficient technique for video coding applications in some recent research works. When motion compensation is performed with half-pixel accuracy, images need to be interpolated in both temporal subband analysis and synthesis stages. The resulting subband filter banks developed in these former algorithms were not invertible due to image interpolation. In this paper, an invertible temporal analysis/synthesis system with half-pixel-accurate motion compensation is presented. We look at temporal decomposition of image sequences as a kind of down-conversion of the sampling lattices. The earlier motion-compensated (MC) interlaced/progressive scan conversion scheme is extended for temporal subband analysis/synthesis. The proposed subband/wavelet filter banks allow perfect reconstruction of the decomposed video signal while retaining high energy compaction of subband transforms. The invertible filter banks are then utilized in our 3-D subband video coder. This video coding system does not contain the temporal DPCM loop employed in the conventional hybrid coder and the earlier MC 3-D subband coders. The experimental results show a significant PSNR improvement by the proposed method. The generalization of our algorithm for MC temporal filtering at arbitrary subpixel accuracy is also discussed.
在最近的一些研究工作中，带运动补偿的三维（3-D）子带/小波编码已被证明是一种用于视频编码应用的有效技术。当以半像素精度执行运动补偿时，在时间子带分析和合成阶段都需要对图像进行插值。由于图像插值，在这些先前算法中开发的子带滤波器组是不可逆的。本文提出了一种具有半像素精度运动补偿的可逆时间分析/合成系统。我们将图像序列的时间分解视为采样晶格的一种下变频。早期的运动补偿（MC）隔行/逐行扫描转换方案被扩展用于时间子带分析/合成。所提出的子带/小波滤波器组允许对分解后的视频信号进行完美重建，同时保持子带变换的高能量压缩性。然后，可逆滤波器组被用于我们的3-D子带视频编码器。该视频编码系统不包含传统混合编码器和早期MC 3-D子带编码器中使用的时间DPCM环路。实验结果表明，所提出的方法显著提高了峰值信噪比（PSNR）。我们还讨论了将算法推广到任意子像素精度的MC时间滤波。
