Optical flow method
Optical flow is the velocity of pixel motion object projecting in the image plane. It is a technique used to describe image motion. The research of optical flow is to determine each pixel’s motion by researching the pixels intensity change with time. It is usually applied to a series of images that have a small time step between them, for example, video frames. Optical
flow calculates a velocity for points within the images, and provides an estimation of where points could be in the next image sequence