利用块特性的自适应十字搜索模式运动估计法  

An algorithm of adaptive rood pattern search using characteristic of different kinds of block

作　　者：夏金祥[1] 黄顺吉[1] 

机构地区：[1]电子科技大学电工学院电子工程系701-4,成都610054

出　　处：《信号处理》2005年第6期621-627,共7页Journal of Signal Processing

摘　　要：运动估计和补偿在MPEG-4编码器和解码器中占用资源最多,人们直寻求较有竞争力的运动估计和补偿 的算法。本文提出的利用块特性的自适应十字搜索模式运动估计法,它充分利用VOP的块的特性,不同的块采用不同的 运动估计策略。首先,VOP的边框内块分三类。当前块为VOP的透明块时,不进行运动估计,由解码端直接生成。当前 块为VOP的边界块时,参考帧不填充,边界块间的SAD计算采用二值α平面值计算。当前块为VOP的模糊块时,模糊 块的SAD计算采用灰度值计算。其次,对进行运动估计的块,先排除静止块,对运动块,采用自适应十字搜索模式。利 用块特性的自适应十字搜索模式运动估计法极大地提高了搜索效率,同时计算量显著减少,并且具备较好的峰值信噪比, 是一种较有潜力的运动估计和补偿算法。Motion estimation and compensation costs the most resource in MPEG-4 encoder and decoder, and people are always seeking the emulative algorithm of motion estimation and compensation. This paper proposes an algorithm of adaptive rood pattern search using the characteristic of different kinds of block, in which the different strategy is used for different kinds of block. First, the blocks of VOP bounding box is classified into the transparent blocks, the boundary blocks, and the opaque blocks. For the transparent blocks, the motion estimation is not needed, and is generated by the decoder. For the boundary blocks, the padding process in the referenced frame is not required, and its SAD （the sum of absolute difference） is computed by the binary alpha planes＇ values. For the opaque blocks, its SAD is computed by the pixels＇ intensities. Second, for the blocks with motion estimation, the static blocks are prejudged, for the moving blocks, an adaptive rood pattern search is used. The proposed approach of motion estimation improves greatly the efficiency of searching, and also the computation load is reduced remarkably with good PRSN （peak ratio of signal to noise）. The proposed approach of motion estimation is very potential.

关 键 词：运动估计和补偿 块特性 自适应十字搜索模式 VOP MPEG-4 

分 类 号：TN919.81[电子电信—通信与信息系统] TP393.4[电子电信—信息与通信工程]