一种运动估计的快速预测搜索算法
A NEW PREDICTIVE SEARCH ALGORITHM USED FOR MOTION ESTIMATION IN MPEG2
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摘要: 本文提出了一种运动估计的快速预测搜索算法(PSA)。该算法首先用当前块的三个邻近块运动矢量的线性加权来得到预测矢量,然后以预测点为起始点,采用33的搜索窗进行搜索步长为1的移动窗搜索,直到搜索到达搜索域的边界或搜索的局部最小点位于搜索窗的中心时停止。该算法由于利用了序列图象的实际运动矢量与预测矢量之间距离的空间分布特性一中心偏置分布特性和时间上的相关特性,并采用了中止判决准则,可以明显地减少搜索次数。仿真表明这种算法减少了搜索范围和搜索次数,提高了搜索效率,降低了运动估计的计算复杂性。本文还详细地给出了PSA算法与其它常用快速算法的比较结果。
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关键词:
- 运动估计; MPEG2; 预测搜索算法
Abstract: A new predictive search (PSA) algorithm is proposed in this paper, where the search displacements are between -16 to +15.5. It firstly derives motion vector from the linear weighting of motion vectors of the three adjacent blocks, then searches from the prediction point using 3 3 search window and search with the step of one until it reaches the boundary of search area or the local minimum point lies in the center of search window. Based on the spatial characteristics of center-biased distance between motion vector and corresponding prediction vector and temporal correlation of motion vectors, this method can significantly reduces the search times. Simulation results show that the proposed PSA is efficient to reduce the search range, search times, and computational complexity. Comparisons of PSA with other fast search algorithms are also given in detail. -
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