A parallel implementation method of FFT-based full-search block matching algorithms

One category of fast full-search block matching algorithms (BMAs) is based on the fast Fourier transformation (FFT). This paper proposes a parallel implementation method of FFT-based full-search BMAs. The FFT-based full-search BMAs are much faster than the direct full-search BMA, and its accuracy is as same as the direct full-search BMA. However, these are not designed for parallel processing. The proposed method divides the search window into multiple sub search windows using the overlap-save method, and the FFT-based full-search BMA is applied to each sub search window. These sub search windows are processed in parallel. By dividing the search window, the method can not only process in parallel, but also select the efficient FFT size. Furthermore, the method can also calculate two cross-correlations at the same time. These properties also contribute to speeding up of the block matching. The experimental results shows that the method on 6 cores CPU is about 11 times faster than the conventional FFT-based full-search BMA.