Dense Pyramidal LK Optical Flow example resides in L2/examples/lkdensepyrof directory.
This benchmark tests the performance of lkdensepyrof function with a pair of images. Optical flow is the pattern of apparent motion of image objects between two consecutive frames, caused by the movement of object or camera. It is a 2D vector field, where each vector is a displacement vector showing the movement of points from first frame to second.
The tutorial provides a step-by-step guide that covers commands for building and running kernel.