Patent ID: 7204428
Filing Date: 2007-04-17
Classification: G06K

Abstract:
1. A two-dimensional identifier applied to an object for encoding a value so that the value is determinable when the two-dimensional identifier is placed adjacent to a surface sensing system, the two-dimensional identifier comprising: (a) a cue component comprising a contiguous radial area of a detectable material to which the surface sensing system is responsive and which is approximated as an ellipse when detected by said surface sensing system, said ellipse having axes that indicate an orientation of the two-dimensional identifier relative to a coordinate system of the surface sensing system, the radial area including a sub-area comprising the non-detectable material disposed at a first predefined radius from a center of the radial area, the sub-area representing a start bit that indicates a start location from which the code portion is to be read; (b) a code portion disposed in a predefined location relative to the cue component, said code portion encoding the value with at least one binary element that is detectable by the surface sensing system; and (c) a border region that encompasses the cue component and the code portion, the border region comprising a non-detectable material that is not sensed as part of the two-dimensional identifier by the surface sensing system and which functions as an interference mask around the cue component and the code portion, to minimize noise.