HIERARCHICAL MOTION ESTIMATOR (HME) FOR BLOCK-BASED VIDEO CODERS

A hierarchical block-based motion estimation strategy for video sequen ce coding is proposed, which allows to reduce both the computational l oad and the number of transmitted motion vectors, The estimation is pe rformed by first computing a coarse motion field at the lowest resolut ion of a Gaussian pyramid and then propagating and refining it till th e maximum resolution, Main innovations concern the adaptive vector pro pagation and updating strategy, which allow an efficient recovery from wrong estimates while maintaining a low computational load, The advan tages of the proposed method are manifold: first, it is able to decrea se the computation of even two orders magnitude for an equivalent comp ensation; second, it generates a lower number of motion vectors, resul ting in a lower information rate; third, it produces a more homogeneou s motion field, thus easing a successive segmentation.