运动估计UMHexagonS算法的研究与改进

An improvement on the motion estimation algorithm:UMHexagonS

针对UMHexagonS算法计算复杂、耗时等问题提出改进算法。首先，通过在预测起始点处增加了准静止块闽值来判断是否可以立即停止搜索；然后，用扩展的菱形搜索代替原算法中的5×5的螺旋式全搜索以降低计算复杂度；最后，利用多层次8点八边形代替多六边形网格搜索。实验结果表明，改进算法在保证图像质量的前提下可以有效地减少10％～30％的运动估计时间，提高了总体的编码性能。

According to the problems that UMHexagonS ＇algorithm have high computational complexity and time-consuming, the article proposed three improvements. Firstly, the algorithm increase a quasi-stationary block threshold at the forecast starting point for early termination; Then, in order to reduce the computational complexity, 5×5 spiral-full-search of UMHexagonS algorithm is replaced by the extended-diamond search. Finally, we use the eight point multi-octagon-grid search to replace the multi-hexagongrid search. Experimental resuhs demonstrate that the proposed algorithm can reduce about ten to thirty percent of the searching time of the motion estimation without loss of its accuracy, and improves the coding performance.