OpenCV notes - Optical Flow

Optical Flow - for e.g. tracking how far an object has moved from
current position. For e.g. tracking a nod/shake of a face.

OpenCV's calcOpticalFlowPyrLK function implements the Lucas-Kanade
method of computing optical flow.

OpenCV function called goodFeaturesToTrack, selects features based on
the algorithm described below :

As the name suggests, the Good Features to Track algorithm (also known
as the Shi-Tomasi algorithm) attempts to select features that work
well with the algorithms of tracking and the use cases of tracking.