基于节点搜索的可变形块运动补偿

本文讨论可变形块匹配(DBMA)的运动补偿和预测方法,提出基于节点搜索的可变形块匹配算法(NS-DBMA),并在此基础上提出分数像素精度预测和双模式混合预测方法.实验结果表明,NS-DBMA比全搜索方块匹配法(EBMA)平均改善约2dB;其运算量仅为基于梯度的可变形块匹配算法(GB-DBMA)的一半,但能得到更好的主客观预测质量,且更易于VLSI硬件实现.

适可而止的基于节点搜索的可变形块运动补偿

基于节点搜索的可变形块搜索是一种新型的运动估计方法,它比传统的基于平移的运动搜索有更高的精度,但该方法运算量比较大。本文在基于节点搜索可变形块运动补偿算法中采用适可而止的措施,对搜索精度足够的非平移块终止当前搜索,直接跳到半像素精度搜索。实验结果表明,只要门限选择得当,就能以预测质量降低很小的代价换来运算速度的大幅提高。

基于节点交叉搜索的可变形块匹配运动估计算法

文章在讨论可变形块(DBMA)的运动估计和基于节点位移的可变形块运动模型的基础上,提出了基于节点交叉搜索的可变形块匹配算法(CS-DBMA)。以四节点模型为例,详细研究了该算法的搜索过程和流程,并利用两个序列进行测试,测试结果表明,在预测效果减少很小的情况下,CS-DBMA算法的运算量大大的减少。

A fast block-matching algorithm based on variable shape search

Block-matching motion estimation plays an important role in video coding. The simple and efficient fast block-matching algorithm using Variable Shape Search (VSS) proposed in this paper is based on diamond search and hexagon search. The initial big diamond search is designed to fit the directional centre-biased characteristics of the real-world video se- quence, and the directional hexagon search is designed to identify a small region where the best motion vector is expected to locate. Finally, the small diamond search is used to select the best motion vector in the located small region. Experimental results showed that the proposed VSS algorithm can significantly reduce the computational complexity, and provide competitive computational speedup with similar distortion performance as compared with the popular Diamond-based Search (DS) algorithm in the MPEG-4 Simple Profile.