Abstract: An object position and orientation detection system and in particular one which is capable of describing observed movement in 3 dimensions. In one example, a spherical patterned marker with concentric rings is imaged using one or more digital cameras, and the resulting images are processed to determine the position and orientation of an object to which the patterned marker is attached. The method of optical tracking employed by the system allows motion to be determined in six degrees of freedom. In conjunction with a suitable display, such as a projector, an interactive white board or similar application can be realized.