Block-Matching Algorithm Based on Dynamic Search Window Adjustment

Dynamic search window adjustment for block-matching algorithm(BMA) based on the block similarity to overcome the computational complexity of full search BMA is presented. The proposed method for adjustment of the size of search window is performed with three steps:(1)Set newsearch origin basedonblock similarity anddisplacedblockdifference(DBD), as a displacement of the block which has smaller DBD between the zero displaced and the displaced as much as adjacent block’s motion vector that has maximum block similarity. (2)Adjust the size of searchwindow in inverse proportion to block similarity, and (3)Update the thresholds for accommodation to a given image sequence. The technique can be easily applied for full search BMA or several fast search algorithms such as TSS, NTSS, OTS, PHODS, etc. to get more efficiency and less falling into local-minimum. Experimental results show that the proposed technique has good performance in terms of the number of matching blocks, and sum of absolute error for each block, compared with an adjustment of search window using initial set and using adaptive adjustment scheme proposed by [12], when these techniques for search window adjustment are applied for full search(FS), three-step search(TSS), new three-step search(NTSS).