We recently demonstrated an Active Appearance Model-based, real-time face tracker for the Nokia N900 using VXL:
so it is certainly possible. Unfortunately, we can't release the code for licensing reasons but we have recently committed a simple shape model library (in vxl/contrib/mul/msm) which should get you some way along the line. You'd also have to figure out how to get head pose from the feature points - we haven't got that far yet.
Phil Tresadern.

From: Wim Vriend [facetracknoir@gmail.com]
Sent: 03 December 2010 13:51
To: vxl-users@lists.sourceforge.net
Subject: [Vxl-users] How to use VXL in Visual C++ to track a face realtime?

Hello VXL-users,

I am developer of an open-source program called FaceTrackNoIR and I'm looking for ways to expand (and improve) my program. As you can see in the web-site, FaceTrackNoIR uses the SeeingMachines faceAPI to retrieve the rotations and translations of the users face. Then the program translates these values and sends them to a game/flightsim using the appropriate protocol. Movement of the face then results in movement of the in-game character.

I found VXL on the internet and I wonder if it is possible to use it as real-time facetracker? The faceAPI has some serious drawbacks (it's not open-source, support is 'zero' and it's quite CPU-demanding). I would like to offer users the option to choose a different tracker...

Has anyone done something like this before?

Thanks in advance,

Wim Vriend