SIGGRAPH 2011, where a gaggle of gurus with IQs far, far higher than ours explained in detail what the future of 3D face scanning would hold. Scientists from ETH Zürich, Texas A&M, Technion-Israel Institute of Technology, Carnegie Mellon University as well as a variety of folks from Microsoft Research and Disney Research labs were on hand, with each subset revealing a slightly different technique to solving an all-too-similar problem: painfully accurate 3D face tracking. Haoda Huang et al. revealed a highly technical new method that involved the combination of marker-based motion capture with 3D scanning in an effort to overcome drift, while Thabo Beeler et al. took a drastically different approach.
Those folks relied on a markerless system that used a well-lit, multi-camera system to overcome occlusion, with anchor frames acting as staples in the success of its capture abilities. J. Rafael Tena et al. developed "a method that not only translates the motions of actors into a three-dimensional face model, but also subdivides it into facial regions that enable animators to intuitively create the poses they need." Naturally, this one's most useful for animators and designers, but the first system detailed is obviously gunning to work on lower-cost devices -- Microsoft's Kinect was specifically mentioned, and it doesn't take a seasoned imagination to see how in-home facial scanning could lead to far more interactive games and augmented reality sessions. The full shebang can be grokked by diving into the links below, but we'd advise you to set aside a few hours (and rest up beforehand).