Kinect Scaling in C++ - c++

Question

I am experimenting with the kinect, however I am having some problems with scaling. The below is code from the kinect-kcb and although the face tracking works for the 'mesh' I am having problems returning the scaling value for my own classes. The below code returns a correct rotation and translation which function perfectly, but the scale only ever returns 1 for a long period (despite the mesh clearly changing size) and then slowly gets smaller 0.98... etc but clearly not correct scaling values.
float scale;
float rotation[ 3 ];
float translation[ 3 ];
hr = mResult->Get3DPose( &scale, rotation, translation );
if ( SUCCEEDED( hr ) ) {
Vec3f r( rotation[ 0 ], rotation[ 1 ], rotation[ 2 ] );
Vec3f t( translation[ 0 ], translation[ 1 ], translation[ 2 ] );
face.mPoseMatrix.translate( t );
face.mPoseMatrix.rotate( r );
face.mPoseMatrix.translate( -t );
face.mPoseMatrix.translate( t );
face.mPoseMatrix.scale( Vec3f::one() * scale );
}
This scale value is used repeatedly thoughout the code, but does not seem to change often enough (example functions - not in order):
hr = mModel->Get3DShape( shapeUnits, numShapeUnits, animationUnits, numAnimationUnits, scale, rotation, translation, pts, numVertices );
hr = mModel->GetProjectedShape( &mConfigColor, mSensorData.ZoomFactor, viewOffset, shapeUnits, numShapeUnits, animationUnits,
numAnimationUnits, scale, rotation, translation, pts, numVertices );
The kinect has a function FaceModel.Scale(), however this only returns a constant value which I assume is the initial scaling value for the 3D model, and then I assumed the above scaling value would change as the user moved closer and further away from the camera.

Answer 1

The method IFTResult::Get3DPose among other things, gives you the face scale value. If it is equal to 1.0 then the face scale is equal to the loaded 3D model (so nothing to do?).
If when reloading the 3d model, the face value is not equal to 1.0 then you need to do work on the model.
have you tried outputting some debug info of what IFTResult::Get3DPose assigns to pScale?
its also possible that the system is failing to track, you can check this with IFTResult::GetStatus.
It may be that what you are after is the magnitude of the face rectangle. This would scale with the proximity of the image subject.
Heres a relevant code project link.