Binary glyph codes based on color relationships

• US 5,684,885 A
• Filed: 09/27/1995
• Issued: 11/04/1997
• Est. Priority Date: 09/27/1995
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Cass, Todd A., Marimont, David H.
• Primary Examiner(s): JOHNS, ANDREW W
• Application Number:
  US08/534,521
• Time in Patent Office: 769 Days
• Field of Search: 382/100, 382/112, 382/162, 382/165, 382/166, 382/232, 235/465, 235/469, 235/494, 283/72, 283/114, 380/9, 380/54
• US Class Current: 382/100
• CPC Class Codes: G06K 19/06018 one-dimensional coding
• CPC Class Codes: G06K 7/143 Glyph-codes

Abstract

Binary digital data is rendered on a surface, such as a sheet of paper, by printing a series of color patches on the sheet, with the 1 bits rendered as color patches of a first color and the 0 bits rendered as color patches of the second color. The color patches are arranged in a predetermined order along an axis on the surface. The second color relates to the first color by a fixed relationship in color space, whereby the absolute values of the first and second colors are immaterial to a detecting apparatus. The color patches can be intermixed with areas of a third color, the third color representing an average in color space of the first color and the second color.

Claims

1. A method of creating a document bearing digital information on a surface, the digital information comprising bits in a first state and bits in a second state arranged in a predetermined relative order, comprising the steps of:

assigning each bit of the digital information to one of a set of small areas on the surface, the small areas being regularly spaced along an axis on the surface, the bits being assigned in the predetermined relative order to the small areas along the axis;

for each bit in the first state, printing a color patch of a first color in the assigned small area; and

for each bit in the second state, printing a color patch of a second color in the assigned small area,

the color patches being printed contiguously on the surface along the axis resulting in a region appearing to be substantially homogenously-colored to a casual observer.

2. The method of claim 1, wherein the digital information further comprises bits in a third to an Nth state, and further comprising the step of

for each bit in each state of the third to Nth state, printing in the assigned small area a color patch of a unique color for each state.

3. A method of creating a document bearing digital information on a surface, the digital information comprising bits in a first state and bits in a second state arranged in a predetermined relative order, comprising the steps of:

assigning each bit of the digital information to one of a set of small areas on the surface, the small areas being regularly spaced along an axis on the surface, the bits being assigned in the predetermined relative order to the small areas along the axis;

for each bit in the first state, printing a color patch of a first color in the assigned small area;

for each bit in the second state, printing a color patch of a second color in the assigned small area; and

printing on the surface a color patch of a third color, the third color being located in color space on a vector between the first color and the second color.

4. The method of claim 3, wherein the color patches of the first color and second color are printed as islands within a background of the third color.

5. The method of claim 3, further comprising the step of printing at least a subset of color patches in the shapes of geometric data glyphs.

6. The method of claim 3, further comprising the step of printing at least a subset of color patches as alphanumeric characters.

7. The method of claim 3, wherein the digital information further comprises bits in a third to an Nth state, and further comprising the step of

for each bit in each state of the third to Nth state, printing in the assigned small area a color patch of a unique color for each state.

8. A method of reading a document bearing digital information on a surface, the digital information comprising color patches regularly spaced along an axis on the surface, the color patches comprising color patches of a first color and color patches of a second color, the first color patches and the second color patches being arranged along the axis in a predetermined relative order, comprising the steps of:

determining an average color of a large number of small areas on the surface;

calculating a location of the first color in color space, the first color being of a predetermined relationship in color space with the average color;

detecting, in the document, local concentrations of pixel areas of the first color;

calculating a location of the second color in color space, the second color being of a predetermined relationship in color space with the first color;

detecting, in the document, local concentrations of pixel areas of the second color;

determining spatial relationships, in the document, of the local concentrations of pixel areas of the first color and the local concentrations of pixel areas of the second color; and

deriving binary data from the spatial relationships of the local concentrations of pixel areas of the first color and the local concentrations of pixel areas of the second color.