The Dense Pyramidal LK Optical Flow example resides in the L2/examples/lkdensepyrof directory.
This benchmark tests the performance of the 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 an object or camera. It is a 2D vector field, where each vector is a displacement vector showing the movement of points from the first frame to the second.
The tutorial provides a step-by-step guide that covers commands for building and running a kernel.