WO2001033495A1 - Procedes et systemes utilisant de multiples filigranes - Google Patents

Procedes et systemes utilisant de multiples filigranes Download PDF

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Publication number
WO2001033495A1
WO2001033495A1 PCT/US2000/029454 US0029454W WO0133495A1 WO 2001033495 A1 WO2001033495 A1 WO 2001033495A1 US 0029454 W US0029454 W US 0029454W WO 0133495 A1 WO0133495 A1 WO 0133495A1
Authority
WO
WIPO (PCT)
Prior art keywords
document
watermarks
watermark
original
wear
Prior art date
Application number
PCT/US2000/029454
Other languages
English (en)
Inventor
Geoffrey B. Rhoads
Ammon E. Gustafson
Original Assignee
Digimarc Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Digimarc Corporation filed Critical Digimarc Corporation
Priority to EP00973864A priority Critical patent/EP1264268A1/fr
Priority to AU12320/01A priority patent/AU1232001A/en
Publication of WO2001033495A1 publication Critical patent/WO2001033495A1/fr

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T1/00—General purpose image data processing
    • G06T1/0021—Image watermarking
    • G06T1/005—Robust watermarking, e.g. average attack or collusion attack resistant
    • G06T1/0071—Robust watermarking, e.g. average attack or collusion attack resistant using multiple or alternating watermarks
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/0002—Inspection of images, e.g. flaw detection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00002—Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00002—Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for
    • H04N1/00005—Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for relating to image data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00002—Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for
    • H04N1/00026—Methods therefor
    • H04N1/00037—Detecting, i.e. determining the occurrence of a predetermined state
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00002—Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for
    • H04N1/00092—Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for relating to the original or to the reproducing medium, e.g. imperfections or dirt
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32288—Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
    • H04N1/32304—Embedding different sets of additional information
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2201/00—General purpose image data processing
    • G06T2201/005—Image watermarking
    • G06T2201/0083—Image watermarking whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious

Definitions

  • the present invention relates to steganography, and more particularly relates to the use of multiple watermarks to determine the authenticity or history of a particular document or image.
  • the present invention is directed to an improved technique for using steganography and digital watermark technology to facilitate differentiating original documents from copies of the original.
  • the present invention can also be used for various other purposes such as to embed multiple types of information in a single document or to provide watermarks that enable documents to perform special functions. .
  • the detection process or mechanism reads the two digital watermarks and compares their characteristics. While wear and handling may change the characteristics of the individual watermarks, the relationship between the characteristic of the two watermarks will never-the-less give an indication as to whether a document is an original or a copy of an original.
  • two digital watermarks in a document may have different energy levels.
  • the absolute energy level of a digital watermark in an original image may be decreased if a document is subject to wear.
  • the energy level of the digital watermark in an image may be decreased if an image is scanned and reprinted on a color printer.
  • the relationship between the energy level of the two digital watermarks will be different in an image that has been subject to wear and in a reproduced image.
  • the ratio between the signal to noise ratio of the watermarks will be different in an original subject to wear and in a copy generated by scanning the original and printing the scanned image.
  • Other characteristics of multiple digital watermarks can also be used to differentiate original documents from copies.
  • a watermark-independent assessment of wear can be performed, and the results used to aid in differentiating original documents from copies.
  • Figure 1 shows the paths that a document and a copy may follow.
  • Figures 2A and 2B show a fine grain and a course grain watermark.
  • Figure 3 A and 3B show a geometrically linear and a geometrically random assignment of pixels to a bit in a digital watermark.
  • Figure 4 illustrates a fourth embodiment of the invention.
  • a number of different watermarks are embedded in a document.
  • Each of the watermarks embedded in the document has a different character. All watermarks are somewhat affected when a document is subjected to wear, and all watermarks are somewhat affected when a document is duplicated by being scanned and reprinted. However, the magnitude of the effect caused by being scanned and reprinted on watermarks with certain characteristics is much greater than the effect on watermarks with different characteristics. Likewise, wear and handling of a document affects watermarks with certain characteristics much more than it affects watermarks with different characteristics.
  • CMYK cyan, magenta, yellow, black
  • the present invention takes advantage of the fact that if an original is copied and then a copy is printed, the image on the printed copy will have gone through several conversions to which the original will not have been subjected.
  • the conversions to which a copy may be subjected are:
  • any characteristics of the two digital watermarks that will be affected differently by the additional conversion process to which copies are subjected can be used to differentiate copies from an original. Since the two watermarks with different characteristics are affected in a different manner by the additional conversion step, a comparison of the characteristics of the two watermarks in a document being examined will indicate if the document is an original (which has not gone through the additional conversions) or a copy which has gone through the additional conversions. While the characteristics of each watermark will have been changed by wear and by the copying process, the comparison between the characteristics of the two watermarks will still be able to differential a copy from an original.
  • First watermark Has fine grain
  • Second watermark Has a course grain
  • First watermark Has geometrically linear assignment of pixels
  • Second watermark Has geometrically random assignment of pixels.
  • First watermark Has low power
  • Second watermark Has higher power
  • First watermark uses standard RGB to HSI and HSI to RGB transformations
  • Second watermark is biased before being transformed from HSI to RGB.
  • Figure 1 shows the steps to which documents and copies are typically subjected.
  • a document 10 may be subjected to handling and wear 11 resulting in a worn document 10A.
  • Document 10 may also be scanned as illustrated by box 12. The scanning produces a digital image that can be printed, as illustrated by box 13. The printed image may be subjected to handling and wear 14 resulting in a copy 10B. It is noted that the document 10 may also be subject to handling and wear prior to the scanning operation 12.
  • the task to which this invention is directed is the task of differentiating the worn document 10A from the copy 10B.
  • the document 10 includes an image (not explicitly shown) that has two digital watermarks inserted therein.
  • the first watermark has a fine grain and the second watermark has a course grain.
  • the grain of the two watermarks is illustrated in Figure 2.
  • Figure 2 A shows the grain of the first watermark and figure 2B shows the grain of the second watermark.
  • the first watermark uses blocks of 9 pixels (a 3 by 3 block). Each of the pixels in each 9 pixel block has its gray value changed by the same amount.
  • Figure 2A shows that the first 9 pixel block has its gray value increase and the second 9 pixel block has its gray value decreased. The amount of increase and the selection of blocks that is increased and decreased is conventional.
  • the grain of the second watermark is in blocks that are 6 pixels by 6 pixels or 36 pixels. All of the pixels in each 36 pixel block are changed by the same amount.
  • the two watermarks have power ratios of 1 to 1.
  • the power of the first watermark will be degraded somewhat more than the power of the second watermark.
  • a detector which reads the watermarks might find that the power ratio of the water marks is 1 to 2. If the document 10 is scanned and the resulting digital image is printed to make a copy of the document 10, the ratio of the power of the watermarks will be affected much more than the effect of handling and wear.
  • the power ratio of the watermarks maybe 1 to 10, thereby allowing one to differentiate the worn original document 10A from the copy 10B.
  • the mechanism for inserting watermarks into an image is well known, as is the technique for reading a watermark and using correlation techniques to determine the signal to noise ratio (i.e. the power) of a watermark.
  • Figures 3 A and 3B show an alternative technique for implementing the present invention.
  • the two watermarks inserted into the image on a document have different patterns of assigning pixels to the bits of the payload represented by the watermark.
  • the first watermark utilizes a geometrically linear assignment of pixels to each bit.
  • Figure 3 A shows an image that has 500 by 500 pixels.
  • each bit of the watermark would have 5000 pixels assigned to represent that bit.
  • a linear assignment could have each fifth bit in each row (100 bits per row) and each fifth row (50 rows) assigned to each bit of the watermark.
  • 5000 pixels would be assigned to each bit in a very orderly or linear manner.
  • the watermark with a linear assignment of pixels and the watermark with a random assignment of pixels would be affected differently by handling and wear on the original document than they would be by being scanned and reprinted.
  • the third embodiment of the invention described herein utilizes watermarks that have different power levels. Handling and wear as contrasted to scanning and printing would affect a watermark with a low power level differently than a watermark with a high power level. Watermarks with different power levels can be inserted into a document in order to practice the present invention utilizing commercially available programs such as Adobe Photoshop or Corel Draw. In the Adobe Photoshop and Corel Draw programs, the power or intensity of the watermark can be adjusted by setting a simple control setting in the program.
  • the fourth embodiment of the invention introduces different characteristics into two watermarks by modifications made to one of the watermarks during the initial step during which the watermarks are introduced into an image.
  • the operation of the fourth embodiment can be explained as shown in Figure 4.
  • the first watermark is inserted into the image in a conventional manner by modifying the I value in the HSI representation of the image using the first watermark values (designated as WMl ⁇ ).
  • a first RGB value designated RGB(l) is then calculated using a conventional transformation designated T.
  • the second watermark WM2 is then biased toward a particular color and the biased watermark is then combined with the HSI values and transformed to a second set of RGB values designated RGB(2).
  • the values RGB(l) and RGB(2) are combined to form the watermarked image designated RGB(F).
  • RGB to HSI color space can be anyone of a variety of known other techniques.
  • the RGB to HSI conversion can be one of the techniques explained in the above referenced text book such as the following: (which assumes that RGB and Intensity have a value range of 0 to I and that Red equals 0°): First calculate:
  • the HSI values are converted to RGB values using a transform "T".
  • HI must be between 0 and 360, SI must be non-negative and can be between 0 and 1 and X is a value between 0 and 1)
  • RGBF RGBF
  • the wear of the document can be independently assessed and used to aid in distinguishing an original from a copy.
  • the wear of the document can be assessed.
  • Various means can be used to distinguish document wear.
  • One is high frequency content, as can be determined by high pass filtering the document image data, or performing an FFT, DCT, etc.
  • a worn document typically loses some high frequency energy.
  • contrast - a worn document typically loses contrast.
  • color gamut - a worn document may fade to a less varied gamut.
  • luminance the soiling of a document can decrease the overall document brightness.
  • physical integrity - a worn document droops when only partially supported.
  • Still other means is a quick human assessment of wear, with human entry of a corresponding datum into a system (e.g., on a wear scale of 0 to 10, or simply "crisp,” “used,” or “very worn”). Still other means can similarly be employed.
  • the wear can be graded on an arbitrary scale, depending on the particular measurement means used. In an illustrative case, wear may range from 0 ("crisp") to 7(extreme). In the Fig. 5 example, the x point may be at wear value 5. In distinguishing the documents, a look-up table, microprocessor-implemented algorithm, or other arrangement can be provided that takes as its input the ratio and wear values, and produces outputs, e.g., as follows:
  • the different watermarks can be of entirely different types.
  • one watermark can comprise slight alterations to the image normally printed on a document
  • the second can comprise a texture formed on the document substrate, or a background weave or tint pattern - both of which convey watermark data.
  • texture-, weave- and tint-based watermarks are shown, e.g., in copending applications 09/074,034 (filed May 6, 1998), 09/127,502 (filed July 31, 1998), 09/151,492 (filed September 11, 1998), patent 5,850,481, and laid-open PCT publication WO 99/53428.
  • Documents may include multiple similar watermarks in addition to the watermarks having different characteristics according to the present invention.
  • the term "document” generally refers to a physical entity.
  • the same methodologies can also be applied to purely digital images - e.g., to detect losses that an image has suffered through a lossy compression/decompression process such as JPEG or MPEG, color re-balancing, etc., and thereby discern something about the history of a digital image.
  • Such an apparatus can include a scanning ID, or stationary 2D image sensor (e.g., CMOS or CCD), and a microprocessor suitably programmed to discern first and second watermarks in image data provided by the sensor (as well as wear, if desired). (In some cases, a stationary ID sensor may be employed.)
  • CMOS or CCD complementary metal-oxide-semiconductor
  • Such apparatus further includes an output device - such as a display screen, indicator light, audible tone, voice synthesizer, or equivalent device - to provide an appraisal of the document's validity based on the sensed information.
  • a similar apparatus can be provided for use by Customs officials at ports of entry to check merchandise tags, packaging, labels, and other printed indicia associated with clothing, purses, electronic components, software, and other readily-counterfeitable goods, to determine whether the sensed tag/package/label is an original, or a copy. While such a determination may not provide the confidence needed to seize a shipment as counterfeit, it could flag the goods as suspect and needing further inspection and/or forensic analysis.

Abstract

Au moins deux filigranes numériques présentant des caractéristiques numériques sont intégrés à un document (10). Les caractéristiques sont choisies de sorte que les filigranes subissent des altérations de différentes sortes si le document fait l'objet d'une copie ou d'une reproduction ultérieure. Le processus ou le mécanisme de détection permet la lecture d'au moins deux filigranes et la comparaison de leurs caractéristiques. Alors que l'usure et la manipulation (11) peuvent modifier les caractéristiques des filigranes numériques d'un document, la relation entre les caractéristiques de multiples filigranes numériques d'un document permet cependant de donner une indication sur le fait qu'un document est un original ou une copie d'original (10B). L'usure d'un document peut être évaluée de manière indépendante et utilisée comme un élément facilitant l'interprétation des caractéristiques de filigranes détectés.
PCT/US2000/029454 1999-01-20 2000-10-25 Procedes et systemes utilisant de multiples filigranes WO2001033495A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP00973864A EP1264268A1 (fr) 1999-01-20 2000-10-25 Procedes et systemes utilisant de multiples filigranes
AU12320/01A AU1232001A (en) 1999-11-03 2000-10-25 Methods and systems using multiple watermarks

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US23478099A 1999-01-20 1999-01-20
US09/433,104 1999-11-03

Publications (1)

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WO2001033495A1 true WO2001033495A1 (fr) 2001-05-10

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5617119A (en) * 1994-06-08 1997-04-01 Systems Research & Applications Corporation Protection of an electronically stored image in a first color space by the alteration of a digital component in a second color space
US5664018A (en) * 1996-03-12 1997-09-02 Leighton; Frank Thomson Watermarking process resilient to collusion attacks
US5687236A (en) * 1995-06-07 1997-11-11 The Dice Company Steganographic method and device
US5825892A (en) * 1996-10-28 1998-10-20 International Business Machines Corporation Protecting images with an image watermark
US5862218A (en) * 1996-04-04 1999-01-19 Fotonation, Inc. Method and apparatus for in-camera image marking and authentication
US5933798A (en) * 1996-07-16 1999-08-03 U.S. Philips Corporation Detecting a watermark embedded in an information signal
US5974548A (en) * 1996-07-12 1999-10-26 Novell, Inc. Media-independent document security method and apparatus

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5617119A (en) * 1994-06-08 1997-04-01 Systems Research & Applications Corporation Protection of an electronically stored image in a first color space by the alteration of a digital component in a second color space
US5893101A (en) * 1994-06-08 1999-04-06 Systems Research & Applications Corporation Protection of an electronically stored image in a first color space by the alteration of digital component in a second color space
US5687236A (en) * 1995-06-07 1997-11-11 The Dice Company Steganographic method and device
US5664018A (en) * 1996-03-12 1997-09-02 Leighton; Frank Thomson Watermarking process resilient to collusion attacks
US5862218A (en) * 1996-04-04 1999-01-19 Fotonation, Inc. Method and apparatus for in-camera image marking and authentication
US5974548A (en) * 1996-07-12 1999-10-26 Novell, Inc. Media-independent document security method and apparatus
US5933798A (en) * 1996-07-16 1999-08-03 U.S. Philips Corporation Detecting a watermark embedded in an information signal
US5825892A (en) * 1996-10-28 1998-10-20 International Business Machines Corporation Protecting images with an image watermark

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