Global motion model based on B-spline wavelets: application to motion estimation and video indexing

This paper describes a framework to estimate a global motion model based on B-spline wavelets. The wavelet-based model allows optical flow to be recovered at different resolution levels from the image derivatives. By combining estimation from different resolution levels in a coarse to fine scheme, our algorithm is able to recover a large range of velocity magnitudes. Our algorithm is evaluated on artificial and real image sequences and provides accurate optical flows. The wavelet coefficients of the model at low resolution levels also provide features to index video or to recognize activities. Preliminary experiments on video indexing based on coarse wavelet coefficients are presented. As an example, we have considered video sequences containing different human activities. Wavelet coefficients are efficient to give a database partition related to the kind of human activities.