In my second year of under grad, after getting inspired from MIT Media Labs's SixthSense project, I went forward and built Finger Mouse. This project allows the users to control the mouse pointer of their computer through a camera. The users have to wear coloured markers on two of their fingers and using gestures, actions such as mouse single click and mouse double click can be done.
I further extended this mouse to be used with a first-person shooter game - Counter Strike to augument the physical actions of game playing into the the virtual world to give the gamer a more realistic experience.
HCI, Image Processing