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absolute joint coordinates & pacing newframeready event RRS feed

  • Question

  • Hello,

    Having a lot of fun lwith the kinect sdk, thank you Microsoft.

    May i ask 2 questions :

    1°) I want to know how still is a joint. Therefore i guess i should add (skeleton.position.x + skeleton.jointid.position.x) to have the absolute movement in the x plane. Correct?

    1bis°) Would you know the confidence interval (sigma) of the joint coordinates?

    2°) Because i want to record the position at precise time intervals, i use a timer 100. But i guess because a newframereadyevent isn't ready i have a 10% delay. Is there a way to reduce hardware framerate so that i have exactly 10 Hz recording (or is there another way to do that)?

     

    Thank you very much

     



    Tuesday, August 9, 2011 11:54 PM

Answers

  • yes, if you move camera above TV from a lower level then Y coordinates will change even though you didn't move.

    Some kind of scarecrow would work better than a poster, since a scarecrow is more similar to a person in 3D space. The kinect is able to detect people even if they aren't moving, so as long as your object looks similar enough to a person, whether it is moving or not shouldn't matter.

    Hope this helps,
    Eddy


    I'm here to help
    • Marked as answer by Sambafr Thursday, August 11, 2011 5:58 PM
    Thursday, August 11, 2011 12:27 AM

All replies

  • 1) SkeletonData.Joints[JointID].Position.X is already an absolute position relative to X axis, so you don't need to add the overall skeleton position to make this into an absolute value. If you want to measure movement in X plane, you could subtract X position of joint in a previous frame from X position of joint in current frame:

    Single diffX = newFrame.Skeletons[i].Joints[JointID].Position.X - oldFrame.Skeletons[i].Joints[JointID].Position.X;

    1bis) The Kinect SDK beta does not provide confidence values for joint positions, sorry.

    2) Sorry, SDK does not let you specify desired framerate. Frames are always delivered whenever they become available, at a rate of approx 30 frames per second.

    Hope this helps,
    Eddy


    I'm here to help
    Wednesday, August 10, 2011 7:15 PM
  • Thanks for your answer,

    If i understand correctly, the x,y,z plan is not defined by the joint but by the camera (origin); ex: if i put the camera above the tv (it was under before) the y coordinates will change, eventhough i didn't move?, Correct?

     

    What still object could i get to test the cameras confidence values? A poster of a man or some sort of scarecrow? Is it possible to dazzle kinect by using something that looks like a man but that isnt moving?. Does someone have an idea, i need the confidence values for my project?

     

    Thak you again for your help

     

    Thursday, August 11, 2011 12:12 AM
  • yes, if you move camera above TV from a lower level then Y coordinates will change even though you didn't move.

    Some kind of scarecrow would work better than a poster, since a scarecrow is more similar to a person in 3D space. The kinect is able to detect people even if they aren't moving, so as long as your object looks similar enough to a person, whether it is moving or not shouldn't matter.

    Hope this helps,
    Eddy


    I'm here to help
    • Marked as answer by Sambafr Thursday, August 11, 2011 5:58 PM
    Thursday, August 11, 2011 12:27 AM
  • thanks
    Thursday, August 11, 2011 5:58 PM