(with Allan Jepson)
This work develops a new model for estimating optical flow based on the motion of planar regions plus local deformations. The approach exploits brightness information to organize and constrain the interpretation of the motion by using segmented regions of piecewise smooth brightness to hypothesize planar regions in the scene. Parametric flow models are estimated in these regions in a two step process which first computes a coarse fit and estimates the appropriate parameterization of the motion of the region (two, six, or eight parameters). The initial fit is refined using a generalization of the standard area-based regression approaches. Since the assumption of planarity is likely to be violated, we allow local deformations from the planar assumption in the same spirit as physically-based approaches which model shape using coarse parametric models plus local deformations. This parametric+deformation model exploits the strong constraints of parametric approaches while retaining the adaptive nature of regularization approaches. Experimental results on a variety of images indicate that the parametric+deformation model produces accurate flow estimates while the incorporation of brightness segmentation provides precise localization of motion boundaries.
Black, M. J. and Jepson, A., Estimating optical flow in segmented images using variable-order parametric models with local deformations, IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 18, No. 10, Oct. 1996, pp. 972-986.
Black, M. J. and Jepson, A., Estimating multiple independent motions in segmented images using parametric models with local deformations, Workshop on Non-rigid and Articulate Motion, Austin, Texas, Nov. 1994, pp. 220-227. (postscript)