Question

I’m building a kinect driven .net app, is it possible to limit the kinect’s detection distance?

Its like i have an interactive shopping window that is controlled by a kinect, i want only the person who steps on the X mark on the ground to be detected or lets say the person who is 3 meters far from the sensor to be detected.
If anybody is closer than the 3 meters or farther than that it wouldn’t detect him.

I use VB.Net for coding although most of the codes are translated from C#, any help is greatly appreciated.

Thanks.

Answer 1

In your SkeletonFrameReady callback, you likely have a foreach loop (or similar) to step through your active skeletons. You should also be looking to see if they are actively tracked.

foreach (Skeleton skeleton in _skeletons) {

    // some extra setup stuff here...

    if (skeleton.TrackingState != SkeletonTrackingState.Tracked)
      return;

    // the Kinect is actively tracking the skeleton at this point

    ...
}

What you want to do at this point is check the Z position of the person. Pick a joint you want to use as reference — I’d suggest the head, hip or spine. If the Z position is where you want it to be, continue to act on the skeleton.

foreach (Skeleton skeleton in _skeletons) {
    ....

    if (skeleton.TrackingState != SkeletonTrackingState.Tracked)
      return;

    if (skeleton.Joints[JointType.Spine].Position.Z < _minValue || skeleton.Joints[JointType.Spine].Position.Z > _maxValue)
      return;

    // if you reach this point, the person is standing a certain distance from the Kinect.  Not too close, not too far away.

}

You will want to check a range for the Z position. It can be a small range, but you want to give the user enough space to move a little without the Kinect ignoring them.

UPDATE: You may also be able to use the Position property from the Skeleton. It has a single x/y/z reference to a calculated point for the entire skeleton in the Kinect’s FOV.