Motion estimation using complex wavelets

This paper describes a new wavelet-based approach to the motion estimation problem for digital video. A complex-valued discrete wavelet transform is used to decompose each frame into a subsampled directionally bandpass filtered hierarchy. The transform is defined so that at each level there is an approximate correspondence between local translation and coefficient phase shift. This relationship is used to estimate motion within each orientation subband. 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. The technique is suitable for video compression schemes and can also be used for stereo vision and image registration