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Detecting a thrown object hitting a wall in front of the camera?

asked 2017-05-11 03:03:56 -0500

goolag gravatar image


Has anyone any ideas on how I would detect a thrown object hitting a wall in front of the camera - the object could originate from any angle so I'm racking my brains on how I would determine when the object impacted the wall.

For example, I have the camera a fixed distance perpendicular to a wall - if i throw a ball at the wall, I want to track it then determine the moment of impact against the wall.

Would I use the diameter of the ball? As the ball moved further from the camera, the perceived diameter would shrink - I could then take the calibrated diameter and camera distance and assume the ball had hit the wall.

Does that make sense, is it possible or is there a better way


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answered 2017-05-11 04:32:59 -0500

kbarni gravatar image

Check the optical flow methods in OpenCV.

For this application you can use a sparse optical flow (much faster than the dense optical flows).

To detect the impact, check the high values in the derivatives of the path.

Another idea would be to use a PCA based optical flow analysis and check when the Lambda2 increases. (maybe check this code I found on google?

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Asked: 2017-05-11 03:03:56 -0500

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Last updated: May 11 '17