US 7,204,428 B2 · Identification of object on interactive display surface by identifying coded pattern

Abstract

A coded pattern applied to an object is identified when the object is placed on a display surface of an interactive display. The coded pattern is detected in an image of the display surface produced in response to reflected infrared (IR) light received from the coded pattern by an IR video camera disposed on an opposite side of the display surface from the object. The coded pattern can be either a circular, linear, matrix, variable bit length matrix, multi-level matrix, black/white (binary), or gray scale pattern. The coded pattern serves as an identifier of the object and includes a cue component and a code portion disposed in a predefined location relative to the cue component. A border region encompasses the cue component and the code portion and masks undesired noise that might interfere with decoding the code portion.

Claims26

Dependent claims

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.

1 more element

A method for determining a value from a two-dimensional identifier applied to an object when the object is placed adjacent to a surface of a surface sensing system, comprising the steps of:

(a) detecting a cue component of the two-dimensional identifier, the cue component comprising a contiguous area that is detectable by the surface sensing system and is encompassed by a border region that is not sensed by the surface sensing system as being part of the two-dimensional identifier and which functions as an interference mask around the cue component to minimize noise;
(b) approximating the cue component as an ellipse having a major axis and a minor axis, to determine a position and orientation of the cue component relative to the surface sensing system;
(c) locating a beginning of a code portion of the two-dimensional identifier relative to the position and orientation of the cue component, the value being encoded in the code portion by a plurality of binary elements, each of a predefined area and the code portion also being encompassed by the border region, which also functions as an interference mask around the code portion to minimize noise;
(d) detecting the plurality of binary elements at predefined locations relative to one of the beginning of the code portion and to each other, with the surface sensing system;
(e) decoding the value that is encoded as a function of the plurality of binary elements that are detected;
and
(f) determining an object identifier associated with the value of the two-dimensional identifier.

4 more elements

A system for determining a value from a two-dimensional identifier applied to an object, comprising:

(a) an interactive display surface having an interactive side adjacent to which the object can be placed, and an opposite side;
(b) a light source that directs infrared light toward the opposite side of the interactive display surface and through the interactive display surface, to the interactive side;
(c) a light sensor disposed to receive and sense infrared light reflected back from the patterned object through the interactive display surface forming an image that includes the two-dimensional identifier applied to the object;
(d) a processor in communication with the light sensor;
and
(e) a memory in communication with the processor, the memory storing data and machine instructions that cause the processor to carry out a plurality of functions, including:
(i) detecting a cue component of the two-dimensional identifier with the light sensor, the cue component comprising a contiguous area that is detectable by the light sensor and is encompassed by a border region that is not sensed by the light sensor as being part of the two-dimensional identifier and which functions as an interference mask around the cue component to minimize noise;
(ii) approximating the cue component as an ellipse having a major axis and a minor axis, to determine a position and orientation of the cue component relative to the interactive display surface;
(iii) locating a beginning of a code portion of the two-dimensional identifier relative to the position and orientation of the cue component, the value being encoded in the code portion by a plurality of binary elements, each of a predefined area and the code portion also being encompassed by the border region, which also functions as an interference mask around the code portion to minimize noise;
(iv) detecting the plurality of binary elements at predefined locations relative to one of the beginning of the code portion and to each other, with the light sensor;
and
(v) decoding the value that is encoded as a function of the plurality of binary elements that are detected.

9 more elements

Dependencies are inferred from the claim text.

Identification of object on interactive display surface by identifying coded pattern

Life of this patent

Identification of object on interactive display surface by identifying coded pattern

Life of this patent

Abstract

Claims26