基于起点预测和SAD分布的快速运动估计算法

基于块的运动估计是视频压缩国际标准中广泛采用的关键技术。文中提出了结合相邻块运动向量相等和SAD值比较的起点预测方法,减少了起点预测时计算SAD的开销;利用SAD分布的方向性,对SAD值偏小部分重点搜索,加速了块匹配的快速搜索策略。在此基础上设计了一种新的快速运动估计算法,该算法在大幅度提高搜索效率的同时,得到了与全搜索非常接近的搜索结果,从而减少或避免了不必要的搜索。

A New Fast Motion Estimation Algorithm Based on Initial Search Point Estimation and SAD Distribution

The block-based motion estimation has been widely used in the international standards of video compression. By combining the equality of the motion vectors of the neighbor blocks and the SAD comparison, this paper presents an initial estimating of the search point, which reduces the cost of computing SAD. According to the directionality of the SAD distribution, a fast search method is proposed to speed up the block matching. Extensive search is taken for the pixels in the direction with smaller SAD, but sparse search for the regions in other directions. A new fast motion estimation algorithm is implemented, which performs as accurate as full-search, but needs much less computation.