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ok newb here... tracking speed of a pitch. RRS feed

  • Question

  • Not sure if kinect sensors could track an object thats 12" in diameter and moving 55-60 mph, any thoughts on this.  What I mean by track is mostly just capturing the speed of the pitch, if I could do strike zone stuff that would be cool to; just not sure if the kinect sensors are capable of capturing this at all. 

    Thanks.

    tr

     

    Monday, June 20, 2011 12:42 AM

Answers

  • troth,

    While the capabilities to do this certainly exist (you could write the object tracking algorithm yourself on top of data provided by depth stream) I would expect a large error when trying to do this with kinect device + SDK, because the frames are not captured/returned at a guaranteed constant rate suitable for precise timing like you'd want for calculating speed of pitch with high accuracy.

    Also, Kinect captures frames at a rate of approximately 30 frames per second and, in the time between frame and frame, an object moving at 60mph would have moved approximately 0.9 meters, and if the diameter is approx 0.3 meters (12 inches), then there would be a large gap between captured object in one frame vs the next, so your tracking algorithm would have to be written to handle that.

    Hope this answers your question,
    Eddy


    I'm here to help
    Tuesday, July 5, 2011 7:51 PM
  • this statement "kinect device + SDK, because the frames are not captured/returned at a guaranteed constant rate"  seems to indicate that the issue is only with the pc/sdk version, is that correct?  Either way thanks for the response!

     

    You'd be better off using a webcam and making a motion tracking algorithm to track it. You'll need a pretty high speed camera if it's moving at 55 - 60 mph. It might also be more accurate to record the video of the object moving and then analyze the frames after so timing doesn't affect the values.
    Friday, July 8, 2011 3:26 PM

All replies

  • troth,

    While the capabilities to do this certainly exist (you could write the object tracking algorithm yourself on top of data provided by depth stream) I would expect a large error when trying to do this with kinect device + SDK, because the frames are not captured/returned at a guaranteed constant rate suitable for precise timing like you'd want for calculating speed of pitch with high accuracy.

    Also, Kinect captures frames at a rate of approximately 30 frames per second and, in the time between frame and frame, an object moving at 60mph would have moved approximately 0.9 meters, and if the diameter is approx 0.3 meters (12 inches), then there would be a large gap between captured object in one frame vs the next, so your tracking algorithm would have to be written to handle that.

    Hope this answers your question,
    Eddy


    I'm here to help
    Tuesday, July 5, 2011 7:51 PM
  • this statement "kinect device + SDK, because the frames are not captured/returned at a guaranteed constant rate"  seems to indicate that the issue is only with the pc/sdk version, is that correct?  Either way thanks for the response!

     

    Friday, July 8, 2011 2:33 PM
  • this statement "kinect device + SDK, because the frames are not captured/returned at a guaranteed constant rate"  seems to indicate that the issue is only with the pc/sdk version, is that correct?  Either way thanks for the response!

     

    You'd be better off using a webcam and making a motion tracking algorithm to track it. You'll need a pretty high speed camera if it's moving at 55 - 60 mph. It might also be more accurate to record the video of the object moving and then analyze the frames after so timing doesn't affect the values.
    Friday, July 8, 2011 3:26 PM
  • Personally for something like that I think I would use an accelerometer strapped to the wrist. Gulf Coast Data Concepts sells a small standalone accelerometer. Realistically you would like want two of them so you can track two body parts at once. It would likely help to know someone that can sew to make an elastic band with velro to hold the device. I assume 6G would be enough. That's about 120 MPH/s acceleration captured at up to 320 samples/sec.

    You could use the Kinect to capture the motion is slow motion. That would be the person performing the pitch doing so in slow motion. That would get you, generally, now the skeleton moves and then the accelerometers could give you more precise data.

    Saturday, July 9, 2011 7:11 AM