Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
IEEE Trans Image Process. 2011 Apr;20(4):1036-46. doi: 10.1109/TIP.2010.2083675. Epub 2010 Oct 4.
Transforms used in image coding are also commonly used to compress prediction residuals in video coding. Prediction residuals have different spatial characteristics from images, and it is useful to develop transforms that are adapted to prediction residuals. In this paper, we explore the differences between the characteristics of images and motion compensated prediction residuals by analyzing their local anisotropic characteristics and develop transforms adapted to the local anisotropic characteristics of these residuals. The analysis indicates that many regions of motion compensated prediction residuals have 1-D anisotropic characteristics and we propose to use 1-D directional transforms for these regions. We present experimental results with one example set of such transforms within the H.264/AVC codec and the results indicate that the proposed transforms can improve the compression efficiency of motion compensated prediction residuals over conventional transforms.
用于图像编码的变换也常用于压缩视频编码中的预测残差。预测残差与图像具有不同的空间特征，开发适应预测残差的变换是很有用的。在本文中，我们通过分析它们的局部各向异性特征来探索图像和运动补偿预测残差特征之间的差异，并开发适应这些残差局部各向异性特征的变换。分析表明，运动补偿预测残差的许多区域具有一维各向异性特征，我们建议对这些区域使用一维方向变换。我们在 H.264/AVC 编解码器内使用一组这样的变换进行了实验，并表明所提出的变换可以提高运动补偿预测残差的压缩效率超过传统变换。
