Christian Giordano shows off an innovative prototype of a face-tracking Ubuntu user interface at the Canonical Design Blog. It's just an exploration and it's not planned to be included in Ubuntu any time soon, but he did publish the source code online so people familiar with Processing and third party libraries can toy with the concept.
During a small exploration we did internally few months ago, we thought about how Ubuntu could behave if it was more aware of its physical context. Not only detecting the tilt of the device (like iPhone apps) but also analysing the user’s presence.
With few hours available, I mock up something very quickly in Processing using a face recognition library (computer-vision).
Despite it could be hard to detect the horizontal position of the user’s head without a camera, we are in no way defining the technology required. The proximity could be in-facts detected with infra-red or ultra-sound sensors.