一種運動估計的快速預(yù)測搜索算法
A NEW PREDICTIVE SEARCH ALGORITHM USED FOR MOTION ESTIMATION IN MPEG2
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摘要: 本文提出了一種運動估計的快速預(yù)測搜索算法(PSA)。該算法首先用當(dāng)前塊的三個鄰近塊運動矢量的線性加權(quán)來得到預(yù)測矢量,然后以預(yù)測點為起始點,采用33的搜索窗進(jìn)行搜索步長為1的移動窗搜索,直到搜索到達(dá)搜索域的邊界或搜索的局部最小點位于搜索窗的中心時停止。該算法由于利用了序列圖象的實際運動矢量與預(yù)測矢量之間距離的空間分布特性一中心偏置分布特性和時間上的相關(guān)特性,并采用了中止判決準(zhǔn)則,可以明顯地減少搜索次數(shù)。仿真表明這種算法減少了搜索范圍和搜索次數(shù),提高了搜索效率,降低了運動估計的計算復(fù)雜性。本文還詳細(xì)地給出了PSA算法與其它常用快速算法的比較結(jié)果。
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關(guān)鍵詞:
- 運動估計; MPEG2; 預(yù)測搜索算法
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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