Techniques for Detecting, Analyzing, and Using Visible Authentication Patterns

• US 20080301767A1
• Filed: 01/06/2005
• Published: 12/04/2008
• Est. Priority Date: 01/06/2004
• Status: Active Grant

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Zhao, Jian, Picard, Justin
• Granted Patent: US 7,937,588 B2
• Time in Patent Office: Days
• US Class Current: 726/2
• CPC Class Codes: G06T 1/0042 Fragile watermarking, e.g. so as to detect tampering
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06T 2201/0081 whereby both original and watermarked images are required at decoder, e.g. destination-based, non-blind, non-oblivious
• CPC Class Codes: G09C 5/00 Ciphering apparatus or methods not provided for in the preceding groups, e.g. involving the concealment or deformation of graphic data such as designs, written or printed messages
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 2201/3263 of a graphical motif or symbol, e.g. Christmas symbol, logo H04N2201/3211 takes precedence
• CPC Class Codes: H04N 2201/3266 of text or character information, e.g. text accompanying an image H04N2201/3226 takes precedence
• CPC Class Codes: H04N 2201/3269 of machine readable codes or marks, e.g. bar codes or glyphs
• CPC Class Codes: H04N 2201/3271 Printing or stamping
• CPC Class Codes: H04N 2201/3281 Encryption; Ciphering
• CPC Class Codes: H04N 2201/3284 for error correction

Abstract

Improved techniques for making copy detection patterns and using them to detect copying relationships between digital representations. The techniques include techniques for including a message in a copy detection pattern without altering the copy detection patterns entropy and reading the message, techniques for using a copy detection pattern on an analog form to determine whether the analog form is an original analog form without reference to a digital representation of the original of the analog form'"'"'s copy detection pattern, techniques for increasing the sensitivity of copy detection using copy detection patterns by modifying one of two copy detection patterns that are being compared to take into account alterations resulting from the copying process, techniques for distributing a copy detection pattern across a document, and techniques for using the entropy of a copy detection pattern to locate the copy detection pattern. Also disclosed are applications of copy detection patterns with copying that involves transformations between the digital and analog forms and with digital-to-digital copying.

Claims

1-52. -52. (canceled)

53. A digital representation of an analog signal, the digital representation being wherein:

the digital representation includes a representation of a copy detection signal that is sensitive to transformations produced by digital-to-analog and analog-to-digital conversions, whereby the representation of the copy detection signal may be used to determine whether another digital representation of the analog signal was made by digitizing an analog signal produced from the digital representation.

54. (canceled)

55. A method of creating a digital authentication pattern that contains a message, the digital authentication pattern belonging to a digital representation and the method comprising:

selecting sets of pattern elements belonging to the digital authentication pattern to carry message elements of the message; and

for each selected set, setting the values of the pattern elements in the set to carry the message element such that the digital authentication pattern'"'"'s ability to detect copying remains substantially unchanged.

56. The method according to claim 55, further comprising setting the values such that the entropy of the digital authentication pattern is substantially unchanged.

57. The method according to claim 55, wherein the message elements specify values belonging to a range thereof;

and a selected set of pattern elements is set to indicate a message element specifying one of the values of the range, in said setting act.

58. The method according to claim 57 wherein the selected set is set using a key, in said setting act.

59. The method according to claim 57 wherein the sets of pattern elements belong to categories thereof, the category of a set of pattern elements indicates the value of a message element contained therein, and the set of pattern elements is given a category as required for the value of the message element, in said setting act.

60. The method according to claim 59 wherein the sets of pattern elements belong to two categories.

61. The method according to claim 59, wherein the values of the pattern elements in the set are inverted to indicate a value belonging to a category, in said setting act.

62. The method according to claim 55, wherein the message is encoded using a key.

63. The method according to claim 55, wherein in said selecting act, a key is used to select the set of pattern elements that an element of the message is inserted into.

64. The method according to claim 55 wherein the pattern element is a primitive element of the digital representation to which the digital authentication pattern belongs.

65. A storage device wherein that:

the storage device contains code which, when executed by a processor, implements the method according to claim 55.

66. A digital authentication pattern that contains a message, the digital authentication pattern comprising:

a plurality of sets of pattern elements, the plurality of sets of pattern elements including sets thereof that carry message elements belonging to the message; and

in a set that carries a message element, the set'"'"'s values are set such that the digital authentication pattern'"'"'s ability to detect copying remain substantially unchanged.

67. The digital authentication pattern according to claim 66, wherein:

the values are set such that an entropy of the digital authentication pattern is substantially unchanged.

68. The digital authentication pattern according to claim 66, wherein:

the message elements specify values belonging to a range thereof; and

in a set that carries message elements, the set'"'"'s values are set to indicate a message element specifying one of the values of the range.

69. The digital authentication pattern according to claim 68 wherein:

the sets of pattern elements belong to categories thereof;

the category of a set of pattern elements indicates the value of a message element contained therein; and

in a set that carries message elements, the set has a category as required for the value of the message element.

70. The digital authentication pattern according to claim 66, wherein:

the pattern element is a primitive element of the digital representation to which the digital authentication pattern belongs.

71. The digital authentication pattern according to claim 70, wherein:

the pattern element is a pixel.

72. The digital authentication pattern according to claim 70, wherein:

the digital representation is a representation of an audio signal and the pattern element is a primitive of the representation of the audio signal.

73. The digital authentication pattern according to claim 70, wherein:

the digital representation is a representation of a video signal and the pattern element is a primitive of the representation of the video signal.

74. A storage device wherein that:

the storage device contains the digital authentication pattern according to claim 66.

75. A method of reading a message contained in a digital authentication pattern that includes a plurality of sets of pattern elements, the method comprising:

selecting sets of the pattern elements from the plurality, said selected sets carrying message elements of the message and the values of said selected set'"'"'s pattern elements being set such that the digital authentication pattern'"'"'s ability to detect copying remains substantially unchanged; and

for each selected set, comparing the selected set with equivalent sets that have a possible value of the message element to determine a value of the message element in the selected set.

76. The method according to claim 75 further comprising after the message has been read, creating an equivalent digital authentication pattern to the digital authentication pattern that contains the message, whereby the digital authentication pattern that contains the message is comparable with the equivalent digital authentication pattern to determine a copying relationship with regard to a digital representation that contains the digital authentication pattern that contains the message.

77. The method according to claim 76 wherein in said creating act, the equivalent digital authentication pattern is created by replacing sets of pattern elements therein that do not carry message elements with equivalent sets of pattern elements that do carry message elements.

78. The method according to claim 75, wherein the message elements specify values belonging to a range thereof;

and the equivalent sets of pattern elements include a set for each of the values in the range thereof.

79. The method according to claim 75 wherein the selection is done using a key, in said selecting act.

80. The method according to claim 78 wherein the sets of pattern elements belong to categories thereof;

the category of a set of pattern elements indicates the value of a message element contained therein and the equivalent sets include a set for each of the categories, in said comparing act.

81. The method according to claim 80, wherein the sets of pattern elements belong to two categories.

82. The method according to claim 80, wherein a set of pattern elements whose original values have been inverted indicates a message element value corresponding to the category of the set of pattern elements, in said comparing act.

83. The method according to claim 75, wherein a message element is repeated in the sets of pattern elements and further comprising comparing sets of pattern elements containing the repeated message element to statistically determine a value of the repeated message element.

84. A storage device wherein that:

the storage device contains code which, when executed by a processor, implements the method according to claim 75.