Fast block-matching motion estimation based on an improved cross-diamond search algorithm

In block motion estimation, search patterns with different shapes or sizes have a large impact on the searching speed and quality of performance. In this paper, we propose an improved cross-diamond search algorithm (ICDS), using large/small cross-search pattern as the initial step for fast block motion estimation in according to center-biased characteristics of motion-vector distribution. In addition, the algorithm uses directional diamond search patterns as the subsequent steps based on direction characteristics of motion vector distribution for large motion vectors. The improvement of ICDS over DS and CDS can be up to a 60% and 35% gain on speedup, respectively. Experimental results show that the ICDS is much more robust, and provides faster searching than other popular fast block-matching algorithms with the comparative distortions.