On the complexity and accuracy of motion estimation using Lie operators

Conventional motion estimation algorithms in video coding consider only translations, which can be readily characterized by displacement motion vectors. We might be able to achieve more accurate motion estimation by enlarging the search windows, at the expense of drastically increased computational complexity. Alternatively, we could also increase the accuracy of motion estimation by taking into account potential non-translation motions of objects in a video scene, without increasing the search window size. In this paper, we conduct a comparative study on the computational complexity of these two methods. We demonstrate that our motion estimation method based on the Lie operators can significantly increase the accuracy of motion estimation, while requiring much lower complexity than the method of enlarged search windows.