  This paper deals with a challenging, frequently encountered, yet not properly
investigated problem in two-frame optical flow estimation. That is, the input
frames are compounds of two imaging layers -- one desired background layer of
the scene, and one distracting, possibly moving layer due to transparency or
reflection. In this situation, the conventional brightness constancy constraint
-- the cornerstone of most existing optical flow methods -- will no longer be
valid. In this paper, we propose a robust solution to this problem. The
proposed method performs both optical flow estimation, and image layer
separation. It exploits a generalized double-layer brightness consistency
constraint connecting these two tasks, and utilizes the priors for both of
them. Experiments on both synthetic data and real images have confirmed the
efficacy of the proposed method. To the best of our knowledge, this is the
first attempt towards handling generic optical flow fields of two-frame images
containing transparency or reflection.
