Secure document design carrying auxiliary machine readable information

• US 7,286,684 B2
• Filed: 06/11/2003
• Issued: 10/23/2007
• Est. Priority Date: 03/17/1994
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B., Rodriguez, Tony F.
• Primary Examiner(s): Johns; Andrew W.
• Application Number:
  US10/460,092
• Publication Number:
  US 20030215112A1
• Time in Patent Office: 1,595 Days
• Field of Search: 382/100, 382/135, 382/232, 380/210, 380/287, 380/54, D19/11, 283/72, 283/85, 283/93, 283/113, 283/57, 283/901, 283/902
• US Class Current: 382/100
• 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 2201/0052 Embedding of the watermark in the frequency domain
• 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 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• 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: 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 1/00846 : based on detection of a dedicated indication, e.g. marks or the like
• CPC Class Codes: H04N 1/00875 : Inhibiting reproduction, e.g. by disabling reading or reproduction apparatus
• 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 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 2201/3226 : 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 2201/328 : Processing of the additional information
• CPC Class Codes: H04N 5/913 : for scrambling ; for copy protection

Abstract

A two dimensional pattern design for secure documents serves as both a machine readable code and an aesthetic part of the documents'"'"' design. A method for generating the design generates a variable auxiliary message comprising message values and maps the message values to a two dimensional pattern of areas on the document. The areas each comprise an arrangement of pixels on the printed document. Depending on a value of the message mapped to a corresponding area, the method assigns a visible structure to the corresponding area. Different visible structures are assignable to a single value of the message to create a visible design having a desired aesthetic appearance.

Claims

1. A method of generating a machine readable code for a printed document, the method comprising:

generating a variable auxiliary message comprising message values;

mapping the message values to a two dimensional pattern of areas on the document;

wherein the areas each comprise an arrangement of pixels on the printed document;

depending on a value of the message mapped to a corresponding area, assigning a visible structure to the corresponding area, wherein different visible structures are assignable to a single value of the message to create a visible design having a desired aesthetic appearance.

2. The method of claim 1 wherein the visible structures form a pattern of lines of varying lengths.

3. The method of claim 2 wherein the different visible structures that are selectively assignable to the single value comprise lines of varying length.

4. The method of claim 1 wherein the auxiliary message is repeated and represented by different patterns in the two dimensional pattern.

5. The method of claim 4 wherein the manner in which the message is represented by the different patterns is dependent on a key.

6. The method of claim 1 wherein the auxiliary message is redundantly spread over the two dimensional pattern using a random number.

7. The method of claim 6 wherein the message comprises binary values and the binary values are randomized into substantially equal probability of two different binary values.

8. The method of claim 1 wherein detection of the machine readable code is integrated with detection of a visible seal.

9. The method of claim 1 wherein the pattern includes a visible calibration signal that forms an artistic element of the printed document.

10. The method of claim 9 wherein the machine readable code is embedded within the artistic element.

11. The method of claim 1 wherein the machine readable code carries information that conelates with or is redundant to readable information on the printed document for authentication of the document by comparing at least a part of the machine readable code with the readable information printed on the document.

12. A computer readable medium on which is stored instructions for performing the method of claim 1.

13. A method of generating a watermarked image, said image being divided into a plurality of areas, said method comprising:

generating a watermark tile that includes luminance change values for pixels which will embed a watermark in an image,

associating said areas in said image with pixels in said watermark tile,

drawing lines between said areas in said image, the lines being dependent at least in part on a relationship of the luminance change values of the pixels in the watermark tile that conespond to the areas where said line is drawn.

14. The method recited in claim 13 where said areas each have an index value that is related to the change value of the associated pixel in said watermark tile.

15. The method in claim 14 where each line is drawn from an area to an adjacent area that has the highest index value.

16. A physical image on a substrate which includes a plurality of lines, said image being divided into a plurality of areas, said image being created by lines drawn between said areas so as to cany a machine readable digital watermark payload, wherein an amount of a line drawn over an area is varied in accordance with a value of a machine readable data element of the digital watermark to be conveyed in the area.

17. A system for creating an image that carries a watermark payload, said system comprising,

means to generate a watermark tile including change values that represent a watermark payload,

means for drawing lines in an image in response to the change values in said watermark tile, whereby said image carries a watermark a payload, wherein an amount of a line drawn over an area is varied in accordance with a value of a machine readable data element of the watermark tile to be conveyed in the area.

18. A physical document that includes a plurality of printed artifacts, said artifacts being created at selected positions in a pattern so as to carry a machine readable variable message payload, the message payload being repeated, scrambled, and mapped to areas within the pattern based on a key used to generate encoded message elements, the message elements having values that correspond to the artifacts, wherein the artifact assigned to a particular value of an element is variable to enable selection of artifacts in a pattern having a desired aesthetic appearance.

19. A physical document that includes a plurality of printed visual objects, said visual objects being created at selected positions so as to carry a machine readable variable message payload encoded into a pattern of the visual objects, the message payload being repeated, scrambled, and mapped to areas on the pattern based on a key used to generate encoded message elements, the message elements having values that correspond to the visual objects, wherein the artifact assigned to a particular value of an element is variable to enable selection of artifacts in the pattern having a desired aesthetic appearance.

20. A system for generating a watermarked image, said image being divided into a plurality of areas, said system comprising,

a memory;

a program stored in the memory for generating a watermark tile which includes change values for the areas which will embed a digital watermark in an image, areas in said image being associated with change values in said watermark tile,

a program stored in the memory for drawing lines between said areas in said output image, the beginning and end of said lines being dependent at least in part on the change values of the pixels in the watermark tile that correspond to the area where said lines begin and end wherein an amount of a line drawn over an area is varied in accordance with a value of a machine readable data element of the watermark tile to be conveyed in the area; and

a processor for executing the program for generating a watermark tile and the program for drawing lines.

21. A method of drawing an image which includes a machine readable digital watermark payload, said image being divided into a plurality of areas,

generating a watermark tile that specifies change values that will represent a watermark payload, and

drawing lines between areas in said image in response to the values in said watermark tile;

wherein said watermark tile has change values for a plurality of pixels, and wherein said image includes at least as many areas as there are pixels in said watermark tile.

22. The method of claim 21 wherein the lines drawn between areas depend upon the change value in the corresponding pixel in said watermark tile.

23. The method of claim 22 wherein the change values in said watermark tile are quantified into fewer levels than the number of levels used to represent change values in the watermark tile.

24. The method of claim 23 wherein said change values are quantified into ten levels.

25. A method of drawing an image in response to change values in a message tile generated by a machine readable message coding program, said tile having change values for a particular number of pixels that represent a particular payload,

quantifying said change values into a selected number of index values,

dividing said image into areas, each area being associated with one pixel change value in said tile, each area having an index value related to the associated pixel change value in said tile,

drawing a line in said image staffing at a selected area by drawing a line from said selected area to an adjacent area having the highest index value,

decreasing the index value of the area where said line started,

drawing another line from the area where said line terminated to the adjacent area having the highest index value, and

repeating said decreasing and said drawing another line for a number of iterations, whereby an auxiliary message reading program is operable to read said particular payload encoded in the lines in said image.