Fast integer-pel and fractional-pel motion estimation for H.264/AVC
Fast integer-pel and fractional-pel motion estimation for H.264/AVC
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DOI：
10.1016/j.jvcir.2004.12.002
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发表时间：
2006-04-01
影响因子：
2.6
通讯作者：
Zheng, Junli
中科院分区：
文献类型：
--
作者：
Chen, Zhibo;Xu, Jianfeng;Zheng, Junli
264/AVC中的快速运动估计算法，其质量性能与全搜索算法相当，并提供了一种在质量性能和搜索速度之间取得平衡的策略。整像素搜索是运动估计中最耗时的模块。本文提出了一种混合的无网格交叉多六边形网格搜索算法，该算法很好地解决了局部极小值引起的运动矢量估计错误问题。结果表明，与快速全搜索算法相比，该算法在搜索时间上节省了90%以上，而对于不同运动范围的所有测试序列，平均PSNR损失小于0.056 dB。分数像素快速搜索在整数运动估计速度得到大幅度提高的情况下是不可忽视的。利用分数像素搜索窗口内误差曲面为单峰的特性，提出了一种中心偏置分数像素搜索（CBFPS）算法，与全分数像素搜索算法相比，该算法可节省30-50%的计算量。提前终止是本文讨论的另一个问题，要构造一个完整的运动估计方法，给出一个统一的方法，可以覆盖广泛的应用，在早期和正确的阶段终止程序肯定是必要的。给出了一种基于标准SAD差（NSD）的模型来辅助终止决策，并通过改变调制因子来实现搜索速度和重建质量之间的折衷。(c)2005年爱思唯尔公司All rights reserved.
This paper gives out a fast motion estimation algorithm for H.264/AVC, which has almost the same quality performance as that of the Full Search scheme and also provides a strategy to balance the quality performance and the search speed. Integer-pel search is the most time consuming module for motion estimation. In this paper a hybrid Unsymmetrical-cross Multihexagon-grid Search (UMHexagonS) algorithm is introduced, which well solves the false motion vector estimation problem because of the local-minimum. As results, it saves more than 90% on search time whereas the averaging PSNR loss is less than 0.056 dB for all tested sequences with different motion extent compared with the Fast Full Search scheme. Fractional-pel fast search is not negligible when the integer motion estimation has been extensively speeded up. By utilizing the property of uni-modal error surface inside the fractional-pel search window, a novel Center Biased Fractional-pel Search (CBFPS) algorithm is proposed in this paper, which can save 30-50% computation compared with the Full Fractional-pel Search scheme. Early termination is another problem discussed in this paper, to construct a complete motion estimation method, giving a uniform method which can cover a wide range of applications, terminating the program at early and right stage is certainly required. A model based on the Normative SAD Difference (NSD) is given to assist the termination decisionmaking, and a tradeoff between the search speed and the reconstructed quality can be achieved by changing a modulation factor. (c) 2005 Elsevier Inc. All rights reserved.