UMHexagonS是H.264视频编码标准中所采用的快速整像素运动估计算法,但在许多实时场景的应用中,该算法还明显存在搜索点数过多、搜索速度较慢的缺憾,急需进一步的改进和优化。在UMHexagonS算法的基础上,提出一种基于运动信息自适应的快速运动估计算法。使用动态搜索窗为不同尺寸的块自适应地分配预测搜索窗;根据当前块的运动剧烈程度选择运动类型自适应的搜索方案;通过分析实际运动序列水平、垂直方向的偏向特性依次采用带方向的十字型搜索和自适应的矩形—菱形搜索;利用预测运动矢量的方向信息采用自适应的多层次八边形区域搜索;并依据块的尺寸大小采用自适应的六边形搜索。实验结果表明,本文算法相比于UMHexagonS算法而言,图像的峰值信噪比(PSNR)平均提高了0.0125 dB,同时运动估计时间减少了13%32%,其场景自适应能力和实时性能都得到了很大的增强。

UMHexagonS is a fast integer-pixelmotion estimation algorithm, which was adopted by the H.264 video coding standard, however, in the application of real-time scenes, there still existing some shortcomings, such as the excessive use of search points and the slow search speed. Therefore, further improvement and optimization is needed for this algorithm. Based on the UMHexagonS algorithm, a new fast motion algorithm based on motion information adaptation is proposed in this paper. Dynamical search windows are used for different-size blocks adaptively. Motion-type adaptation search strategies are adopted by the motion intensity of the current block. In addition, directional cross-shaped search and adaptive rectangle-diamond search are used according to the bias characteristics of actual motion sequences in the horizontal and vertical direction. Then an adaptive octagon search is adopted by using the direction information of motion vectors, and to carry on an adaptive hexagon search for different-size blocks. Experimental results show that the motion estimation time of the novel algorithm is reduced 13%32% and the average PSNR is increased by 0.0125 dB. In addition, both the scenes adaptive ability and real-time performance are strongly strengthened.