Patent ID: 7233320

Claim:
A method of enabling user interaction with computer software running in a computer system via: an interface surface having printed thereon: visible information relating to the computer software, and a plurality of tags, each tag containing at least one perspective feature and coded data indicative of an identity of the interface surface and a location on the surface, said method comprising the steps of: (a) placing a pen, having a nib and an optical sensor, in an operative position relative to the interface surface and sensing at least one tag; (b) calculating a two-dimensional perspective transform of the tag using the sensed at least one perspective feature; (c) generating indicating data using: a known spatial relationship between the pen's physical axis and the pen optical axis, said axes being different from each other; the sensed coded data, and the two-dimensional perspective transform, said indicating data identifying the identity of the interface surface and a position of the pen nib relative to the interface surface; (d) sending the indicating data to a computer system, thereby enabling the computer system to identify at least one interactive element relating to the computer software, and operate the computer software in accordance with instructions associated with the at least one interactive element.