中文说明：一个简单的两帧图片间的光流计算,流表达了图像的变化，由于它包含了目标运动的信息，因此可被观察者用来确定目标的运动情况。 由光流的定义可以引申出光流场，
English Description：
A simple calculation of optical flow between two images, which represents the change of the image, can be used by the observer to determine the motion of the target because it contains the information of the target motion. The optical flow field can be derived from the definition of optical flow,