Methods and systems using multiple watermarks

• US 6,636,615 B1
• Filed: 11/03/1999
• Issued: 10/21/2003
• Est. Priority Date: 01/20/1998
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B., Gustafson, Ammon E.
• Primary Examiner(s): Patel, Jayanti K.
• Application Number:
  US09/433,104
• Time in Patent Office: 1,448 Days
• Field of Search: 382/100, 382/232, 382/112, 382/115, 382/135, 382/284, 380/28, 380/42, 380/232, 380/54, 380/201, 380/203, 705/54, 705/26, 705/51, 345/630, 709/723, 709/217, 713/176, 358/444, 358/3.28, 250/372, 235/380, 283/67-70
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0071 using multiple or alternating watermarks
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2207/30144 Printing quality
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07F 7/08 by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/086 by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/12 Card verification
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: H04N 1/00002 Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for error detection, error correction or monitoring in digital computers or digital computer components G06F11/00
• CPC Class Codes: H04N 1/00005 relating to image data
• CPC Class Codes: H04N 1/00037 Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00092 relating to the original or to the reproducing medium, e.g. imperfections or dirt detecting properties of a sheet H04N1/00681
• CPC Class Codes: H04N 1/32149 Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32304 Embedding different sets of additional information
• CPC Class Codes: H04N 1/32309 in colour image data

Abstract

Two or more digital watermarks, with different characteristics, are embedded in a document. The characteristics are chosen so that the watermarks will be affected in different manners if the document is subsequently copied or reproduced. The detection process or mechanism reads two or more of the watermarks and compares their characteristics. While wear and handling may change the characteristics of the digital watermarks in a document, the relationship between the characteristics of the multiple digital watermarks in a document will nevertheless give an indication as to whether a document is an original or a copy of an original. Document wear can be independently assessed and used as an aid in interpreting the detected watermark characteristics.

Claims

1. A method comprising:

sensing a first parameter related to a first digital watermark in a document;

sensing a second parameter related to a second digital watermark in the document;

sensing a third parameter related to wear of the document; and

by reference to said first, second and third parameters, assessing whether the document is likely an original document.

2. A document including a substrate with printing thereon, the printing comprising at least first and second steganographic watermarks, wherein the first and second steganographic watermarks are designed to change differently when the document is subjected to first and second corruption processes.

3. The document of claim 2 where the document is one of the group consisting of a product label, a product tag, product packaging, a banknote, a coupon, and a food stamp.

4. The document of claim 2 in which the first corruption process includes wear, and the second corruption process includes scanning and printing.

5. A method comprising:

sensing a first parameter related to a first digital watermark from a document;

sensing a second parameter related to a second digital watermark from the document; and

by reference to at least the first and second parameters, assessing whether the document is likely an original document, wherein the first and second digital watermarks are designed to change differently when subjected to a corruption process.

6. A method comprising:

sensing a first parameter related to a first digital watermark from a document;

sensing a second parameter related to a second digital watermark from the document;

sensing a third parameter related to wear of the document; and

by reference to said first, second and third parameters, assessing whether the document is likely an original document, wherein sensing of the first and second parameters comprises visible light scanning of the document to retrieve the first and second parameters.

7. A method comprising:

sensing a first parameter related to a first digital watermark from a document;

sensing a second parameter related to a second digital watermark from the document; and

by reference to at least the first and second parameters, assessing whether the document is likely an original document, wherein the first digital watermark comprises a relatively higher likelihood of withstanding a corruption operation, while the second digital watermark comprises a relatively lower likelihood of withstanding the corruption operation.