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Can tracker calculate speed of a squash ball?
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Can tracker calculate speed of a squash ball?
March 17, 2020 4:13PM UTC
Ferris Hussein
1 Posts
I would like to use my phone camera to record the speed of a squash ball before and after it hits the front wall. This can be around 150 mph and the ball is the size of a ping pong ball. Is this doable?
Re: Can tracker calculate speed of a squash ball? -
Apr 9 7:10PM UTC
Michael Jenner
1 Posts
Hi, You can calculate an estimate of how much the object moves through the scene during the exposure time in percent by using the formula: vobj/(2*fps*Dscene)*100 where vobj is velocity of object in m/s. fps is frame rate in frames per second, Dscene is dimension of scene in direction of motion - in meter. Assuming you are recording with a scene dimension of 1m, with velocity of 67 m/s (~150mph) with a frame rate of 30 fps: 67/(2*30*1)*100 ~= 112 % you will probably not see the ball in this video. If your camera can do 240 fps: 67/(2*240*1)*100 ~= 14 % This will still be very blurry and most likely useless. If your phone supports 960fps you can get "down" to 3,5% of scene per exposure time which seems ok. Note, you will need to ensure good contrast between ball color and background. Kind regards, Michael