Robustly estimating changes in image appearance

We propose a generalized model of image ''appearance change" in which brightness variation over time is represented as a probabilistic mixture of different causes, We define four generative models of appearance change due to (1) object or camera motion: (2) illumination phenomena: (3) specular reflections: and (4) "iconic changes" which are specific to the objects being viewed. These iconic changes include complex occlusion events and changes in the material properties of the objects. We develop a robust statistical framework for recovering these appearance changes in image sequences. This approach generalizes previous work on optical flow to provide a richer description of image events and more reliable estimates of image motion in the presense of shadows and specular reflections. (C) 2000 Academic Press.