I want to track an object(for example, a moving ball) in a video. Referring to opencv tutorial - 'Features2D + Homography to find a known object', I have been able to track my object in a still image by providing a reference image. I plan to use a reference image to detect the moving object from the first frame of input video. For the next frame the object detected in previous frame should act as a reference image and so on.
But I don't know how to find back an object from its descriptor. An image having several objects in it will have several keypoints, but how to find whick keypoint or bunch of keypoints belong to which object in an image.