Research on differential approach based optical flow computation

Optical flow aims to measure motion field from the apparent motion of the brightness pattern. It has high value both in theory and application. The paper systematically introduces the history of optical flow and the basic theory of differential approach. Ingredients for an accurate and robust optical flow are deeply discussed, including brightness constancy, gradient constancy and smoothness constraint. Then, several ways are considered to combine these ingredients in an optimal energy function. Also, multigrid method is described in detail, which shows good performance in accelerating the iterative process. At last, the paper points out some possible trends for further research.