True-motion estimation with 3-D recursive search block matching

A new recursive block-matching motion estimation algorithm with only eight candidate vectors per block is presented. A fast convergence and a high accuracy, also in the vicinity of discontinuities in the velocity plane, was realized with such new techniques as bidirectional convergence and convergence accelerators. A new search strategy, asynchronous cyclic search, which allows a highly efficient implementation, is presented. A new block erosion postprocessing proposal further effectively eliminates block structures from the generated vector field. Measured with criteria relevant for the field rate conversion application, the new motion estimator is shown to have a superior performance over alternative algorithms, while its complexity is significantly less