Opencv C++ finding movement in a thresholded image

Question

I am using openCv with C++ and I am trying to find a moving ball under different lighting conditions. So far I am able to filter an image by thresholding it using HSV color space. The problem with this is that it will pick up other object that have a similar color. It is very tedious to figure out the exact hsv range everytime there is a ball with different color/background.

Is there a way for me to apply any filter on the thresholded binary image to detect only the objects that are moving? This way I will only find the ball and not other objects since they are usually stationary.

Thank you,

Varun

Answer 1

Simplest approach would be frame differencing / background learning in an image sequence.

• frame differencing: substract two successive frames, the result is the moving part (you will probably only get the edges of moving objects)

• background learning: eg build an average over 50 frames, this would be your learned background, then substract the current frame, again the difference is the moving part