Method and apparatus for encoding paper with information

• US 7,050,201 B2
• Filed: 08/14/2003
• Issued: 05/23/2006
• Est. Priority Date: 11/10/1999
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Alattar, Adnan M.
• Primary Examiner(s): Rogers, Scott A.
• Application Number:
  US10/642,451
• Publication Number:
  US 20040131225A1
• Time in Patent Office: 1,013 Days
• Field of Search: 358/3.28, 358/1.9, 358/1.11, 358/470, 358/488, 382/100, 382/287, 382289-292, 235/494, 283/113
• US Class Current: 358/3.28
• CPC Class Codes: D21F 11/00 Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
• CPC Class Codes: D21F 9/00 Complete machines for making continuous webs of paper
• CPC Class Codes: G03G 21/046 by discriminating a special original, e.g. a bank note
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain

Abstract

Paper is textured with a pattern that yields a known signature signal when transformed to the frequency domain. This signature can be used for various purposes, including determining the angular orientation of the paper when scanned, conveying a plural-bit digital watermark, and for simple document recognition purposes (e.g., photocopiers that refuse to reproduce banknotes). The texturing can be effected during the paper-making process, e.g., by shaping the surface of a de-watering element accordingly.

Claims

1. A method of marking a paper document comprising:

receiving a first signal comprising plural encoded bits of data;

receiving a second signal comprising an orientation component, the orientation component corresponding to a predetermined frequency domain orientation component; and

in a paper document production process, including a step that imparts into a surface topology of the paper document the first signal and the second signal to thereby steganographically mark the paper document.

2. The method of claim 1, wherein the orientation component comprises plural impulses.

3. A method of marking a paper document comprising acts of:

receiving a signal comprising plural bits of data and an orientation component, the orientation component having characteristics observable in at least one transform domain; and

imparting into a surface topology of a paper document a representation of the signal to thereby steganographically mark the paper document, wherein the representation of the signal is machine-readable from optical scan data representing at least a portion of the paper document.

4. The method of claim 3 wherein the transform domain comprises a frequency domain.

5. The method of claim 3 wherein the paper document comprises a synthetic.

6. The method of claim 3 wherein said imparting utilizes a de-watering element.

7. A method of marking a document comprising acts of:

receiving a plural-component signal, wherein at least one component of the plural-component signal has characteristics that are observable in at least one transform domain; and

shaping a surface of a document in accordance with the plural-component signal to thereby steganographically mark the document, wherein the plural-component signal is machine-readable from optical scan data representing at least a portion of the document.

8. The method of claim 7 wherein the transform domain comprises a frequency domain.

9. The method of claim 7 wherein the document comprises a synthetic.

10. The method of claim 7 wherein said shaping utilizes a de-watering element.

11. The method of claim 7 wherein the plural-component signal comprises a plural-bit message.

12. The method of claim 7 wherein the plural-component signal comprises an orientation component.