New adaptive interpolation schemes for efficient meshbased motion estimation

Motion estimation and compensation is an essential part of existing video coding systems. The mesh-based motion estimation (MME) produces smoother motion field, better subjective quality (free from blocking artifacts), and higher peak signal-to-noise ratio (PSNR) in many cases, especially at low bitrate video communications, compared to the conventional block matching algorithm (BMA). However, the iterative refinement process of MME is computationally much costly and makes the method impractical in real- (or near real-) time systems. Also, eliminating the iterative refinement step deteriorates the motion estimation result. In this paper, we propose motion adaptive interpolation schemes for noniterative MME, which use BMA to compute the motion vectors (MVs) of mesh nodes. The proposed algorithm aims at compromising the MME and BMA by modifying the interpolation patterns (IPPs) of the MME in an adaptive manner, based on the MVs of mesh nodes. Experimental results show notable rate-distortion improvement over both BMA and conventional non-iterative MME, with acceptable visual quality and system complexity, especially when applied to sequences with medium to high motion activities.