摘要
本文对Ｈ．２６３编码算法的现有实现方法作了深入的分析，首先发现变换部分存在大量无效运算，提出了在变换前加判决的前变换判决的编码方案，以压缩无效的变换运算；其次发现运动估计部分由于忽略了图像场景的分级运动而存在一定的无效搜索运算，提出了基于分级运动的可变搜索域法来压缩无效的搜索运算；最后将前变换判决方案与运动估计的可变搜索域法有机地结合在一起，提出了全局判决编码方案，从而比较全面地改进了现有实现方法，因而能大幅度地提高编码器的编码速度．
In this paper,two important modifications in DCT based coding algorithm are suggested after making deep study on the generally used scheme of H.263 coder.First,we find plenty of invalid computation in the transformation part of the H.263 coder and an improved scheme based on the pre transform decision to avoid invalid computation is proposed.Second,in the motion estimation part of the coder,we find that normal search algorithms are not effective,which neglects different levels of motion in image sequences,and we suggest a new search algorithm which has variable search region based on the difference of motion level.Combining the pre transform decision scheme with variable search region method in motion estimation,a global decision coding scheme is provided,which greatly increases the coding speed of H.263 coder.
出处
《电子学报》
EI
CAS
CSCD
北大核心
1999年第4期66-70,共5页
Acta Electronica Sinica
关键词
可变搜索域法
全局判决编码
方案
图像编码
Pre transform decision coding scheme,Variable search region method,Global decision coding scheme,Image coding
