Optimal unified approach to warping and overlapped block estimation in video coding

Among the class of block-based motion estimators, warping prediction and overlapped block motion estimation have emerged recently as two of the most effective inter-frame estimation algorithms. Warping estimation is based on linear operations in the motion field, while overlapped block estimators are based on a linear sum of motion-based estimators in the intensity field. In this paper, we propose a unified framework for estimation of pixel intensities based jointly on warping and overlapped blocks. We motivate our estimator through a discussion of ambiguities in an incomplete (sparsely sampled) motion field; and that different object motions call for resolution of motion ambiguities in either the motion or intensity domain. We offer a means of optimizing the joint estimator simultaneously in intensity and motion domains, thus guaranteeing improved performance compared to warping and overlapped block estimators, which the joint model contains as special cases. Furthermore, the joint framework provides an excellent vehicle for studying the interactions and relative merits of warping and overlapped block estimators in the presence of various motion scenarios.