Hierarchical motion estimation with 2-scale tilings

In this paper, we introduce the notion of 2-scale tilings for block-based hierarchical motion estimation. We propose an algorithm where, at the lowest level in a hierarchy of resolutions, motion estimation is performed using two different block sizes in the block-matching process. At the intermediate levels of resolution, each candidate motion vector is also refined at two different scales; the best motion vector from each scale is propagated to the next resolution for further refinement or pruning. At the full resolution image, one motion vector is selected for refinement for each block on the basis of minimizing the motion-compensated predicted error.