Adapting optical-flow to measure object motion in reflectance and x-ray image sequences (abstract only)

Abstract

This paper adapts Horn and Schunck's work on optical flow to the problem of determining arbitrary motions of objects from 2-dimensional image sequences. The method allows for gradual changes in the way an object appears in the image sequence, and allows for flow discontinuities at object boundaries. We find velocity fields that give estimates of the velocities of objects in the image plane. These velocities are computed from a series of images using information about the spatial and temporal brightness gradients. A constraint on the smoothness of motion within an object's boundaries is used. The method can be applied to interpretation of both reflectance and x-ray images. Results arc shown for models of ellipsoids undergoing expansion, as well as for an x-ray image sequence of a beating heart.