新三步搜索算法考虑了块矢量中心偏移的特性，在初步搜索时对中心周围的

位置同时做了匹配运算。在物体做小范围运动时，这种改进很有效，可以大大减少运算量，然而，在物体做大范围运动时，这种改进却带来了额外的运算量。现实的情况经常是物体既有小范围的偏移，也有大范围的运动。因此，在考虑块匹配算法时，既要照顾块的中心偏移特性，也要兼顾块的大范围运动。四步搜索 (Four-Step Search FSS)能够兼顾两种情况，可以得到较好的性能。

-The new three-step search algorithm to consider the block vector offset characteristics of the Center, in the initial search around the location of the center has done a matching operation at the same time. Done in small-scale movement of objects, this improvement is very effective, can greatly reduce the computational complexity, however, expand the scope of movement in the objects, this improvement has brought about additional computing capacity. Reality both objects are often small-scale migration, there are a wide range of movement. Therefore, in considering the block-matching algorithms, it is necessary to take care of the center block offset characteristics, but also take into account the large-scale block movement. Four-step search (Four-Step Search FSS) to take into account both cases, you can get a better performance.