Computer-supported determination and analysis of moving components in images, often called the optical flow, is a highly complex task and challenging to undertake full analysis at real-time frame rates. For this reason it is only rarely available in imaging libraries.
To achieve satisfactory results a specially adapted version of the so-called block matching technique is used. Using this method the image is divided into blocks within which the displacement of the image content is determined. The flow vectors are calculated for each fixed grid point in the image. Blocks can overlap arbitrarily to reach higher spatial resolutions. Block size as well as step size are freely selectable.
One of the tools to feature this is CVB Optical Flow.