Patent ID: 7895107
Filing Date: 2011-02-22
Classification: G06F,G06K,G06Q,G08C

Abstract:
1. A method of interacting with a printed form, the method comprising the steps of: maintaining a page description corresponding to a printed form in a computer system, said printed form including human-readable content and coded data printed as a collection of tags, each tag being indicative of an identity of the form and of a location of the tag on the form, at least some of the coded data being coincident with the content; receiving, indicating data from an optically imaging pen operated by a user, the indicating data being indicative of the identity of the form and of a position of a nib of the pen relative to the form, the indicating data having been generated by the pen using at least some of the coded data it sensed when placed in an operative position relative to the form; retrieving the page description using the identity of the form; and identifying an interaction with the form using the position of the nib and the retrieved page description, wherein the position of the nib is determined by inferring a perspective transform from perspective-distorted corners of a tag of known size when sensing the coded data and using the perspective transform together with a known geometry of pen optics to compute the position of the nib.