Abstract
Optical flow has been defined as the apparent motion of image brightness patterns in an image sequence. Interpretation of optical flow has typically been made as a geometric entity, namely an image displacement field, consistent with an assumed image brightness transformation model. In this paper, I propose a new mathematical definition, one that permits a unified representation and interpretation of optical flow, based on both geometric and radiometric properties. I investigate the implication of the new interpretation in the context of selected optical flow models. I present results of selected experiments with real images to emphasize the significance of the revised definition.