AN ADJUSTABLE BLOCK MOTION ESTIMATION ALGORITHM BY MULTIPATH SEARCH

Abstract

A speed-quality adjustable block-matching algorithm (BMA) based on multipath flatted-hexagon search (MFHS) is developed for motion estimation. To improve the accuracy of fast BMA near to that of full search (FS), the problem of being trapped at the local minimum block distortion measure (BDM) should be overcome. In the proposed method, an adaptive threshold of BDM is introduced to determine the required search directions in order to escape from being trapped at a minimum BDM, followed by a flatted-hexagon search performed in the direction according to the BDM below a threshold. Then, the motion vector will be refined at each search step unite the searching process is stopped. The BDM threshold will be adaptive for the purpose of adjusting the search speed and matching probability required in the specific application. Experimental results show that the proposed MFHS algorithm can achieve a matching probability upto 99.35% and 13.85 times of search speed of FS in some certain sequence.