Lately I have been working on trying facial recognition with the Kinect, using the new Developer Toolkit (v1.5.1). The API for the FaceTracking tools can be found here: http://m
I working on a project like this one for my master's degree and I am computing distance using mahalanobis distance which is scale-invariant. Here is the formula: d(x,y)=sqrt(Pow((Xi-Yi),2)/Pow(Si,2)) ; i:1-->N, where Si is the standard deviation of the Xi and Yi over the sample set. Here is wikipedia link: http://en.wikipedia.org/wiki/Mahalanobis_distance