Modified full-search block-based motion estimation algorithm with distance dependent thresholds

A modified full-search (MFS) algorithm is presented for block-based motion estimation applications, which introduces the novel concept of variable distance dependent thresholds. The performance of the MFS algorithm is analyzed and quantitatively compared with both the traditional and exhaustive full-search (FS) technique, and the computationally faster, non-exhaustive three-step-search (TSS) algorithm. Experimental results show that by applying an appropriate threshold function, the MFS algorithm not only matches the speed of the TSS algorithm, but both retains a block distortion error comparable to the global minimum produced by the FS algorithm, and avoids the problem of identifying large numbers of spurious motion vectors in the search process.