Fast sub-pixel motion estimation algorithm based on best position calculation

Sub-pixel motion estimation is efficient to improve performance of video compression. Yet the full sub-pixel search algorithm adopted widely nowadays not only seems time-consuming but also leads to exponential growth memory spending for interpolation image as the increasing of sub-pixel accuracy. A fast algorithm is proposed in this paper, which calculates the best position in sub-pixel level directly instead of traditional checking points one by one, then checks two points at most based on the calculated position. As a result, search speed is enhanced greatly without additional memory cost. Experiments show that the algorithm obtains similar PSNR to full sub-pixel search at very low computation cost.