Double-search-window block matching using the fast fourier transform

We propose double-search-window block matching and describe an FFT-based fast algorithm for it. The double-search-window defines two different-sized search windows, an inside-search-window and an outside-search-window, for block-matching. The proposed method achieves the same accuracy as a direct SSD full search in the inside-search-window. It also offers a pseudo-full-search result in the outside-search-window. By evaluating the results comprehensively, the new approach could achieve more precise motion vectors as well as generate the predicted pictures with fewer matching errors, but with almost the same computational load as in the conventional single-search-window block matching.