Gesture-based games using camera phones is a project carried out by the Georgia Tech Mobile Lab

We have developed a collection of mobile phone games that incorporate physical gesture interactions. Users interact with the game by physically moving the phone in free space. For example, in Pong, a user moves the phone left and right to control the paddle. The games do not rely on special motion sensors. Instead, they use the mobile phone's camera as the motion detector. By using computer vision techniques like motion blur detection and optical flow it is possible to detect up to 6 degrees of freedom. We have developed three entertainment applications to explore this application domain. The first is a simple single player Pong game. The second is a Doodle application that demonstrates the various degrees of freedom. The third is a multiplayer version of the Pong game that leverages the Bluetooth capabilities available on many camera phones.

Why do I blog this? their system seems to be compelling: instead of using motion sensors, they take advantage of the camera lens, through motion detection. I am curious to know the accuracy of such a system to embed the tangible interactions they describe.