As a straightforward method , the full search algorithm ( fs ) is widely used because of its high performance . usually , fs is computationally expensive in a video encoder . as a result , in order to reduce the heavy computational load of fs , active research has focused on fast bmas for a long time and several sub - optimal search algorithms for block - based motion estimation have been developed . these include : three step search ( tss ) , four step search ( fss ) , two - d logarithmic search , orthogonal search , cross search , etc 目前块匹配运动估计算法有很多，如全搜索法、三步法、共轭方向搜索法、二维对数搜索法、交叉搜索法、钻石搜索法以及四步搜索法等，它们各有优缺点，全搜索法精度高，但计算量大，三步搜索法和交叉搜索法搜索速度较快，但搜索误差较大，容易陷入局部最小值。
First , in chapter 2 block - based stereo video coding technologies are researched . based on the analyzing of the constraints of disparity distribution and corrections among disparity vectors as well as corrections between motion vectors and disparity vectors , fast algorithms for disparity estimation are proposed . experimental results show the proposed algorithms are efficient 首先在第二章研究了基于块的立体视频编码技术，重点分析了立体视频中视差的特点及其分布特性，研究了视差矢量和运动矢量之间的相关性，在此基础上给出了视差估计的快速算法，进行了实验测试，实验结果显示快速算法有很强的实用性，这是本文的一个创新点。
Many fast block - based motion estimation algorithms have been proposed to reduce the computational complexity , for examples , three - step search , four - step search , new three - step search , etc . most of the fast block matching algorithms are based on the assumption that the block distortion measure increases monotonically as the check point moves away from the global minimum block distortion measure point 这些快速搜索算法大多基于块失真度量随着搜索点偏离最佳匹配点而单调增加的假定,但是这种假定往往只在局部范围成立,对于块失真度量是多极值分布的情况,搜索过程就可能陷入局部最优。
