US Patent 7533816 Method of associating audio with a position on a surface

A method of enabling recorded video to be associated with a location on a surface is provided. The surface has coded data printed thereon, which is indicative of a plurality of locations on the surface. The method comprises the steps of: interacting with the surface using an optical sensing device comprising a video camera; recording video using the video camera; reading some of the coded data during the interaction; determining a position of the sensing device using the read coded data; and communicating, to a computer system, position data indicative of the position of the sensing device and video data corresponding to the recorded video, thereby enabling the computer system to associate the video data with the position.