An object position and orientation detection system and in particular one which is capable of describing observed movement in three dimensions. In conjunction with a suitable display, such as a projector, an interactive whiteboard or similar application can be realised. Elegant methods suitable for calibrating such a system are described, which allow the realisation of pen drawing, for example, without it being necessary to know the exact arrangement of the projector, screen and camera. Methods suitable for aligning a corresponding imaging device are also described, which creates the illusion of a beam from the camera hitting the screen to turn the camera into a 'virtual torch'.
Object position and orientation detection system