<title>Multigrid block-matching motion estimation with an adaptive local mesh refinement</title>

Abstract

Block-based motion estimation and compensation have been efficiently applied in block-based video coding schemes, such as those using DCT, and have been adopted in standards as CCITT/H.261 and ISO/MPEG-II. However, the use of block-based motion estimation techniques in subband coding schemes represents a contradiction, and may introduce block artifacts. In this paper, we present a multigrid block matching motion estimation technique giving more accurate motion field, in the sense of the true motion in the scene, while reaching near optimal solutions in minimizing the energy of the prediction error, when compared to the classical full-search block matching. In addition, a locally adaptive mesh refinement procedure is introduced, allowing more accurate motion fields on edges of moving objects, without increasing the side information required to transmit the motion vectors. The local mesh refinement coarsely approximates a segmentation of the motion field, and reduces block artifacts when the motion estimation is used in a subband coding scheme.