How can i interprete output of opticalflow?

i get u and v motion vectors from opticalflow.How yo interprete values of that output.It shows high values around object boundry only.With out quiver and other line reprsentation,how i can understand values of opticalflow?Because i want to compare motion detection algorithm.like opticalflow and block match.

Answer 1

[Dima Lisin]

Hi Anu,

Getting high flow values at the object's boundary is expected, especially if the object does not have much texture. Let's say you have a video of a white square moving on a black background. The only pixels whose value changes from frame to frame, are pixels on the square's boundary. Everywhere else the flow will be 0.

On the other hand, if the object has some texture, then you will get non-zero optical flow at its interior pixels too.