How to do Joint tracking in Kinect with a scaled Image

Question

I trying to do some Joint Tracking with kinect (just put a ellipse inside my right hand) everything works fine for a default 640x480 Image, i based myself in this channel9 video. My code, updated to use the new CoordinateMapper classe is here

 ...
CoordinateMapper cm = new CoordinateMapper(this.KinectSensorManager.KinectSensor);
ColorImagePoint handColorPoint = cm.MapSkeletonPointToColorPoint(atualSkeleton.Joints[JointType.HandRight].Position, ColorImageFormat.RgbResolution640x480Fps30);

Canvas.SetLeft(elipseHead, (handColorPoint.X) - (elipseHead.Width / 2)); // center of the ellipse in center of the joint
Canvas.SetTop(elipseHead, (handColorPoint.Y) - (elipseHead.Height / 2));

This works. The question is:

How to do joint tracking in a scaled image, 540x380 for example?

Answer 1

The solution for this is pretty simple, i fugured it out.

What a need to do is find some factor to apply to the position. This factor can be found takin the atual ColorImageFormat of the Kinect and dividing by the desired size, example:

Lets say i am working with the RgbResolution640x480Fps30 format and my Image (ColorViewer) have 220x240. So, lets find the factor for X:

double factorX = (640 / 220); // the factor is 2.90909090...

And the factor for y:

double factorY = (480/ 240); // the factor is 2...

Now, i adjust the position of the ellipse using this factor.

Canvas.SetLeft(elipseHead, (handColorPoint.X / (2.909090)) - (elipseHead.Width / 2));
Canvas.SetTop(elipseHead, (handColorPoint.Y / (2)) - (elipseHead.Height / 2));