Digital watermarks and methods for security documents

• US 6,750,985 B2
• Filed: 10/10/2001
• Issued: 06/15/2004
• Est. Priority Date: 03/17/1994
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): Johns, Andrew W.
• Application Number:
  US09/975,739
• Publication Number:
  US 20020080996A1
• Time in Patent Office: 979 Days
• Field of Search: 382/100, 382/135, 382/232, 380/51, 380/54, 380/55, 713/176, 358/3.28, 430/307, 101/3.1, 101/28, 101/32, 101/150, 101/170, 101/368, 101/395, D19/11
• US Class Current: 358/3.28
• CPC Class Codes: B29C 45/1418 the inserts being deformed or preformed, e.g. by the injection pressure
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/40145 Biometric identity checks
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06V 30/40 Document-oriented image-based pattern recognition
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07D 7/0032 using holograms
• CPC Class Codes: G07D 7/0034 using watermarks
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G07F 17/16 for devices exhibiting advertisements, announcements, pictures or the like
• 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 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G07F 7/1016 Devices or methods for securing the PIN and other transaction-data, e.g. by encryption arrangements for secret communication, see H04L9/00
• 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: G11B 20/00094 : involving measures which result in a restriction to authorised record carriers
• CPC Class Codes: G11B 20/00166 : involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/0021 : involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00224 : wherein the key is obtained from a remote server
• CPC Class Codes: G11B 20/00557 : wherein further management data is encrypted, e.g. sector headers, TOC or the lead-in or lead-out areas
• CPC Class Codes: G11B 20/00855 : involving a step of exchanging information with a remote server
• CPC Class Codes: G11B 20/00876 : wherein physical copy protection means are attached to the medium, e.g. holograms, sensors, or additional semiconductor circuitry
• CPC Class Codes: G11B 20/00884 : involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: G11B 20/00891 : embedded in audio data
• CPC Class Codes: H04B 1/665 : using psychoacoustic properties of the ear, e.g. masking effect
• 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 1/00079 : remotely
• CPC Class Codes: H04N 1/00843 : based on recognising a copy prohibited original, e.g. a banknote pattern authentication and markers therefor, forgery detection G06V20/95; character recognition G06V30/10; document-oriented image-based pattern recognition G06V30/40; testing paper currency or similar valuable papers for genuineness G07D7/00
• CPC Class Codes: H04N 1/00846 : based on detection of a dedicated indication, e.g. marks or the like
• CPC Class Codes: H04N 1/00867 : with additional data, e.g. by adding a warning message details of embedding additional information in an image H04N1/32144
• CPC Class Codes: H04N 1/0087 : with hidden additional data, e.g. data invisible to the human eye
• CPC Class Codes: H04N 1/00875 : Inhibiting reproduction, e.g. by disabling reading or reproduction apparatus
• CPC Class Codes: H04N 1/32122 : in a separate device, e.g. in a memory or on a display separate from image data
• CPC Class Codes: H04N 1/32144 : embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32149 : Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32203 : Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 : involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32219 : involving changing the position of selected pixels, e.g. word shifting, or involving modulating the size of image components, e.g. of characters H04N1/32224 takes precedence
• CPC Class Codes: H04N 1/32251 : in multilevel data, e.g. greyscale or continuous tone data
• CPC Class Codes: H04N 1/32261 : in binary data H04N1/32256 takes precedence
• CPC Class Codes: H04N 1/32288 : Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
• CPC Class Codes: H04N 1/32304 : Embedding different sets of additional information
• CPC Class Codes: H04N 1/32352 : Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 2005/91321 : the copy protection signal being a copy protection control signal, e.g. a record inhibit signal
• CPC Class Codes: H04N 2005/91335 : the copy protection signal being a watermark
• CPC Class Codes: H04N 21/23892 : involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 : involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3205 : of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 : of an address
• CPC Class Codes: H04N 2201/3225 : of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 : of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3239 : using a plurality of different authentication information
• CPC Class Codes: H04N 2201/327 : which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3271 : Printing or stamping
• CPC Class Codes: H04N 2201/3274 : Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 2201/328 : Processing of the additional information
• CPC Class Codes: H04N 5/913 : for scrambling ; for copy protection
• CPC Class Codes: Y10S 428/916 : Fraud or tamper detecting
• CPC Class Codes: Y10T 428/24802 : Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

Security documents (e.g. passports, currency, event tickets, and the like) are encoded to convey machine-readable multi-bit binary information (e.g., a digital watermark), usually in a manner not alerting human viewers that such information is present. The documents can be provided with overt or subliminal calibration patterns. When a document incorporating such a pattern is scanned (e.g. by a photocopier), the pattern facilitates detection of the encoded information notwithstanding possible scaling or rotation of the scan data. The calibration pattern can serve as a carrier for the watermark information, or the watermark can be encoded independently. In one embodiment, the watermark and the calibration pattern are formed on the document by an intaglio process, with or without ink. A photocopier responsive to such markings can take predetermined action if reproduction of a security document is attempted. A passport processing station responsive to such markings can use the decoded binary data to access a database having information concerning the passport holder. Some such apparatuses detect both the watermark data and the presence of a visible structure characteristic of a security document (e.g., a printed seal of the document'"'"'s issuer).

Claims

1. A method of producing a security document, comprising:

providing multi-bit binary data;

forming a pattern of recesses in a metal member, said pattern having the multi-bit binary data encoded therein; and

pressing a substrate into said metal member to texture the substrate in accordance with said binary data;

wherein the method includes mathematically transforming the multi-bit binary data into a two-dimensional array of values, and creating the pattern of recesses by reference to the array of values.

2. The method of claim 1 further including inking the recesses prior to the pressing.

3. The method of claim 1 in which the pattern has the multi-bit binary data steganographically encoded therein, wherein a human viewer of the texture on the substrate is not alerted that it conveys multi-bit binary data.

4. A method of producing a security document, comprising:

providing multi-bit binary data;

forming a pattern of recesses in a metal member, said pattern having the multi-bit binary data encoded therein; and

pressing a substrate into said metal member to texture the substrate in accordance with said binary data;

wherein the pattern includes plural features, and the multi-bit binary data is mapped to the features in accordance with an algorithm.

5. The method of claim 4 wherein a change to one bit of the multi-bit binary data results in a corresponding, deterministic change to the pattern.

6. The method of claim 4 further including inking the recesses prior to the pressing.

7. The method of claim 4 in which the pattern has the multi-bit binary data steganographically encoded therein, wherein a human viewer of the texture on the substrate is not alerted that it conveys multi-bit binary data.

8. A method of producing a security document, comprising:

providing multi-bit binary data;

forming a pattern of recesses in a metal member, said pattern having the multi-bit binary data encoded therein; and

pressing a substrate into said metal member to texture the substrate in accordance with said binary data;

wherein certain bits of said multi-bit binary data are derived from others of the bits, and aid in error detection and correction when the pattern is subsequently decoded.

9. The method of claim 8 further including inking the recesses prior to the pressing.

10. The method of claim 8 in which the pattern has the multi-bit binary data steganographically encoded therein, wherein a human viewer of the texture on the substrate is not alerted that it conveys multi-bit binary data.

11. A method of producing a security document, comprising:

providing multi-bit binary data;

mathematically transforming the multi-bit binary data into a two-dimensional array of values;

defining a pattern by reference to said two-dimensional array of values;

providing a printing member shaped in accordance with said pattern; and

pressing a substrate into the printing member to texture the substrate in accordance with the binary data.

12. The method of claim 11 further including inking the shaped printing member prior to the pressing.

13. The method of claim 11 in which the pattern has the multi-bit binary data steganographically encoded therein, wherein a human viewer of the texture on the substrate is not alerted that it conveys multi-bit binary data.

14. A method of producing a security document, comprising:

providing multi-bit binary data;

providing a pattern of indentations in a printing member, the pattern having the multi-bit binary data encoded therein; and

pressing a substrate into the printing member to texture the substrate in accordance with the binary data;

wherein the pattern includes plural features, and the multi-bit binary data is mapped to the features in accordance with an algorithm.

15. The method of claim 14 wherein a change to one bit of the multi-bit binary data results in a corresponding, deterministic change to the pattern.

16. The method of claim 14 further including inking the indentations prior to the pressing.

17. The method of claim 14 in which the pattern has the multi-bit binary data steganographically encoded therein, wherein a human viewer of the texture on the substrate is not alerted that it conveys multi-bit binary data.

18. A method of producing a security document, comprising:

providing multi-bit binary data;

providing a pattern of indentations in a printing member, the pattern having the multi-bit binary data encoded therein; and

pressing a substrate into the printing member to texture the substrate in accordance with the binary data;

wherein certain bits of the multi-bit binary data are derived from others of the bits, and aid in error detection and correction when said pattern is subsequently decoded.

19. The method of claim 18 further including inking the indentations prior to the pressing.

20. A method of producing an encoded document, comprising:

providing multi-bit binary data;

applying an algorithm to map said multi-bit data into a two dimensional pattern that includes plural features; and

impressing indentations into a substrate according to said pattern to thereby shape the microtopology of the substrate, wherein the multi-bit data is steganographically conveyed by said substrate.