Robust motion estimation using complex wavelets

This paper describes a new approach to the problem of estimating motion in video image sequences. The algorithm operates on the complex coefficients obtained by applying the new complex discrete wavelet transform to each frame. This transform implements an efficient analysis by an ensemble of Gabor-like filters of different orientation and scales. The Gabor-like form of the filters means that local translations induce phase rotations in the corresponding complex coefficients. This relationship is used to estimate the motion at each subpixel of each scale. The estimates are combined over all orientations and scales using a coarse-to-fine refinement strategy to produce a fractional-pel accurate motion field with a directional confidence measure. Compared with intensity-based algorithms, the new algorithm is robust to simple image formation perturbations