Computing optical flow using a discrete, spatio-temporal, wavelet multiresolution analysis

This paper describes a wavelet-based system for computing localized velocity fields associated with time-sequential imagery. The approach combines the mathematical rigor of the multiresolution wavelet analysis with well known spatiotemporal frequency flow computation principles. The foundation of the approach consists of a unique, nonhomogeneous multiresolution wavelet filter bank designed to extract moving objects in a 3D image sequence based on their location, size and speed. The filterbank is generated by an unconventional 3D subband coding scheme that generates twenty orientation tuned filters at each spatial and temporal resolution. The frequency responses of the wavelet filter bank are combined using a least-squares method to assign a velocity vector to each spatial location in an image sequence. Several examples are provided to demonstrate the flow computation abilities of the wavelet vector motion sensor.