Adaptive fast matching algorithm based on sub-block ordering

Abstract

In this paper, adaptive fast matching algorithms are proposed based on the sub-block ordering. Proposed two algorithms for the lossless fast matching only reduce the unnecessary matching complexity of motion estimation in the video coding. By observing the expectation of the sum of absolute differences between the current sub-block and a reference sub-block in the pixel domain, we derive an absolute difference model which indicates the relationship between the sub-block distortion and the intra sub-block complexity. In the same way, we consider the inter complexity among all sub-block with the absolute difference model. From the absolute difference model, we derive the transform coefficient model for measuring the sub-block complexity in the transform domain based on the Parseval's theorem. Experimental results show the proposed fast matching algorithms reduce the unnecessary complexity of the full search algorithm about 20% on average without any loss of image quality.