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2016-07-16 00:47:42 -0500 asked a question Detect presence of moving ball in a time block

How to detect position of a moving ball in a video?
Camera position is steady for the duration of the video.

Looking for algorithm or approach. Currently tried:

  1. substracting frames from each other to find difference. (ball is present together with a bunch of other moving parts)
  2. Blur, canny, find contours, make convex hulls
  3. Assume anything with more than 5 points on the convex is a ball
  4. Doesn't work: too many other objects qualify (ie, people moving, birds, trees, w/e
  5. Ball is not round on video. It's a squashed ellipse in motion
  6. Ball movement leaves a trail of 'changed pixels' which are the background that's being uncovered
  7. Ball is not of a single color and not always present / visible
2016-07-04 03:37:28 -0500 commented question Detecting the volleyball net

Nope. On different images camera may be located in different places. The most reasonable assumption to make about position is that the majority of the lower half of the picture is mostly sand and the net is somewhere towards the middle.

2016-07-04 02:35:00 -0500 asked a question Detecting the volleyball net

What would be your approach to detecting the volleyball net on this images.
I am a struggling with coming up with a decent solution.
Unfortunately, bilateralFilter or gaussianBlur all result in a lot of noise (especially the trees and sand) for the canny line detector.

Can you suggest a better course of action ? Any ideas will be appreciated. Specifically, how to filter out sand and trees.

P.S. Also tried inRange based on hue, but the net and the human skin fall within the range of the sand.


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