Fast motion estimation with search-center prediction

Abstract

This paper presents a new block-based motion estimation al- gorithm that employs motion-vector prediction to locate an initial search point, which is called a search center, and an outward spiral search pattern with motion-vector refinement, to speed up the motion estimation process. It is found that the proposed algorithm is only slightly slower than cross search, but has a peak signal-to-noise ratio (PSNR) very close to that of full search (FS). Our research shows the motion vector of a target block can be predicted from the motion vectors of its neighboring blocks. The predicted motion vector can be used to locate a search center in the search window. This approach has two distinct merits. First, as the search center is closer to the optimum motion vector, the possi- bility of finding it is substantially higher. Second, it takes many less search points to achieve this. Results show that the proposed algorithm can achieve 99.7% to 100% of the average PSNR of FS, while it only requires 1.40% to 4.07% of the computation time of FS. When compared with six other fast motion estimation algorithms, it offers the best trade- off between two objective measures: average PSNR and search time. © 2001 Society of Photo-Optical Instrumentation Engineers. (DOI: 10.1117/1.1367865) Subject terms: block matching; motion estimation; search center; motion vector prediction; search pattern.