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Authentication of physical and electronic media objects using digital watermarks

Assignee: Digimarc Corp
•
Filing: 2005-02-03
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Granted: 2008-09-09
•
Expires: 2025-02-03
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Abstract

Abstract Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Another digital watermarking method for authenticating a media object transforms a media signal to a frequency domain comprising an array of frequency coefficients. It selects a first set of frequency coefficients, and alters the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern. The pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.

Inventors

  • 👤 Adnan M. Alattar
  • 👤 J. Scott Carr
  • 👤 Phillip Andrew Seder
  • 👤 Neil Lofgren
  • 👤 Geoffrey B. Rhoads

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 11:08
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/14; G06K7/1404; G06K7/1408; G06K7/1417; B; B42; B42D; B42D25/00; B42D25/30; B42D25/333; G06F; G06F16/00; G06F16/90; G06F16/95; G06F16/955; G06K19/00; G06K19/06; G06K19/06009; G06K19/06037; G06K19/06046; G06K19/08; G06K19/10; G06K19/14; G06K19/18; G06K7/1439; G06K7/1447; G06Q; G06Q20/00; G06Q20/30; G06Q20/34; G06Q20/341; G06Q20/38; G06Q20/40; G06Q20/401; G06Q20/4014; G06Q20/40145; G06T; G06T1/00; G06T1/0021; G06T1/0028; G06T1/005; G06T1/0064; G06V; G06V30/00; G06V30/40; G07; G07C; G07C9/00; G07C9/20; G07C9/22; G07C9/25; G07C9/253; G07D; G07D7/00; G07D7/003; G07D7/0034; G07D7/004; G07F; G07F7/00; G07F7/08; G07F7/086; G07F7/10; G07F7/1008; G10; G10L; G10L19/00; G10L19/018; G11; G11B; G11B20/00; G11B20/00086; G11B20/00884; G11B20/00891; H; H04; H04N; H04N1/00; H04N1/00002; H04N1/00005; H04N1/00026; H04N1/00037; H04N1/00071; H04N1/00074; H04N1/00079; H04N1/00838; H04N1/0084; H04N1/00843; H04N1/00846; H04N1/00856; H04N1/00875; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32154; H04N1/3216; H04N1/32203; H04N1/32208; H04N1/32251; H04N1/32288; H04N1/32352; H04N19/00; H04N19/46; H04N19/467; H04N21/00; H04N21/20; H04N21/23; H04N21/238; H04N21/2389; H04N21/23892; H04N21/80; H04N21/83; H04N21/835; H04N21/8358; G06K2019/06215; G06K2019/06253; G06T2201/00; G06T2201/005; G06T2201/0052; G06T2201/0065; H04L; H04L2463/00; H04L2463/103; H04N1/32106; H04N1/32122; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3204; H04N2201/3205; H04N2201/3207; H04N2201/3225; H04N2201/3226; H04N2201/3233; H04N2201/3269; H04N2201/327; H04N2201/3271; H04N2201/3274; H04N2201/328; H04N2201/3284

Claims Analysis

Total Claims: 52
Claim 1
Independent Claim 49 words
A method for encoding auxiliary data into a host signal comprising: computing a content specific message dependent on the host signal; encoding the content specific message into a watermark signal; embedding the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal.
Claim 2
Independent Claim 49 words
A method for encoding auxiliary data into a host signal comprising: computing a content specific message dependent on the host signal; encoding the content specific message into a watermark signal; embedding the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal.
Claim 3
Dependent Claim 20 words
The method of claim 1 wherein the content specific message represents one or more salient features of the host signal.
Claim 4
Dependent Claim 24 words
The method of claim 2 wherein the host signal comprises an image signal, and the salient features include spatial locations of the salient features.
Claim 5
Dependent Claim 65 words
The method of claim 3 wherein the image signal comprises a photo of a person, and the salient features include one or more of the following facial features of the person in the photo: eyes, nose, and mouth; wherein the photo is authenticated by decoding the spatial locations of the salient features from the watermark and comparing the decoded features with features in the photo.
Claim 6
Dependent Claim 44 words
The method of claim 1 wherein the content specific message comprises a semi-sensitive hash of the host signal, where the semi-sensitive hash is defined as a hash that remains substantially unchanged through digital to analog and analog to digital conversion of the host signal.
Claim 7
Dependent Claim 18 words
The method of claim 5 wherein the semi-sensitive hash comprises a low pass filtering of the host signal.
Claim 8
Dependent Claim 22 words
The method of claim 6 wherein the low pass filtering comprises selecting most significant bits of selected parts of the host signal.
Claim 9
Dependent Claim 26 words
The method of claim 5 wherein the host signal comprises a photo of a bearer of a photo identification document that is printed on the document.
Claim 10
Dependent Claim 51 words
The method of claim 8 further including: encoding a unique identifier of the bearer in the watermark signal such that the photo identification document is authenticated by scanning the photo, decoding the unique identifier from the scanned photo, and comparing the unique identifier with an expected unique identifier for the bearer.
Claim 11
Dependent Claim 25 words
The method of claim 9 wherein the expected unique identifier is read from a different part of the photo identification document other than the photo.
Claim 12
Dependent Claim 31 words
The method of claim 1 wherein the host signal is an image on an object, and the content specific message comprises a unique identifier associated with a bearer of the object.
Claim 13
Dependent Claim 17 words
A computer readable medium on which is stored software for performing the method of claim 1 .
Claim 14
Independent Claim 77 words
A method for authenticating a media object comprising: transforming a media signal to a frequency domain comprising an array of frequency coefficients; selecting a first set of frequency coefficients; altering the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern; wherein the pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.
Claim 15
Independent Claim 77 words
A method for authenticating a media object comprising: transforming a media signal to a frequency domain comprising an array of frequency coefficients; selecting a first set of frequency coefficients; altering the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern; wherein the pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.
Claim 16
Dependent Claim 19 words
The method of claim 13 wherein the coefficients comprise subband coefficients in a wavelet decomposition of the media signal.
Claim 17
Dependent Claim 95 words
The method of claim 13 including: encoding message symbols into the media signal, where the message symbols each have corresponding coefficient values, the encoding including reading a first coefficient in the first set, selecting a coefficient value among the coefficient values corresponding to a symbol to be encoded that results in a minimum change to the first coefficient, replacing the first coefficient in the first set with the selected coefficient value, and repeating the process of reading, selecting, and replacing coefficients to encode one or more additional message symbols in the first set of coefficients.
Claim 18
Dependent Claim 61 words
The method of claim 13 further including: for each coefficient in the first set, selecting a corresponding coefficient in a corresponding set, and changing values of the coefficients in the first set and the corresponding coefficients in the corresponding set such that the differences between the coefficient values in the first set and the corresponding set form a desired delta pattern.
Claim 19
Dependent Claim 14 words
The method of claim 16 wherein the desired delta pattern is a pseudorandom pattern.
Claim 20
Dependent Claim 20 words
The method of claim 17 wherein the pseudorandom pattern is generated from a seed number derived from the media signal.
Claim 21
Dependent Claim 69 words
The method of claim 16 wherein changing values of the coefficients in the first set and the corresponding set includes replacing a coefficient in the first set with a value computed as an average of the coefficient in the first set and the corresponding coefficient in the second set plus a delta value, and replacing the corresponding coefficient in the corresponding set with the average minus the delta value.
Claim 22
Dependent Claim 17 words
A computer readable medium on which is stored software for performing the method of claim 13 .
Claim 23
Dependent Claim 17 words
An object bearing a media signal that has processed according to the method of claim 13 .
Claim 24
Dependent Claim 21 words
An object bearing a host signal that has been encoded with auxiliary data according to the method of claim 1 .
Claim 25
Dependent Claim 66 words
An identification document including: a first image embedded with watermark data and printed on the document; wherein a copy of the first image is embedded with watermark data, and is referenced on the document or encoded into the document; and wherein the watermark data embedded in the first image and the copy is related in a manner that enables validity of the document to be verified.
Claim 26
Dependent Claim 66 words
An identification document including: a first image embedded with watermark data and printed on the document; wherein a copy of the first image is embedded with watermark data, and is referenced on the document or encoded into the document; and wherein the watermark data embedded in the first image and the copy is related in a manner that enables validity of the document to be verified.
Claim 27
Dependent Claim 23 words
The identification document of claim 23 wherein the copy of the first image is stored in a machine readable code on the document.
Claim 28
Dependent Claim 23 words
The identification document of claim 23 wherein the copy of the first image is compressed before being stored in the machine readable code.
Claim 29
Dependent Claim 65 words
The identification document of claim 23 wherein the copy of the first image is stored in a database entry referenced via a database key in the watermark data embedded in the first image printed on the document; and wherein the database key extracted from the watermark in the first image is used to look up the copy of the first image in the database entry.
Claim 30
Dependent Claim 37 words
The identification document of claim 23 wherein the watermark data embedded in the first image printed on the document includes a number that is cryptographically related to a number embedded in the copy of the first image.
Claim 31
Independent Claim 68 words
A method for encoding auxiliary data into a host signal comprising: computing a content specific message dependent on the host signal; encoding the content specific message into a watermark signal; embedding the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal; wherein the content specific message includes data representing locations of one or more salient features of the host signal.
Claim 32
Independent Claim 68 words
A method for encoding auxiliary data into a host signal comprising: computing a content specific message dependent on the host signal; encoding the content specific message into a watermark signal; embedding the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal; wherein the content specific message includes data representing locations of one or more salient features of the host signal.
Claim 33
Dependent Claim 68 words
The method of claim 28 wherein the host signal comprises a photo of a person, and the one or more salient features include one or more of the following facial features of the person in the photo: eyes, nose, and mouth; wherein the photo is authenticated by decoding the spatial locations of the salient features from the watermark and comparing the decoded features with features in the photo.
Claim 34
Dependent Claim 51 words
A decoder for decoding the locations of the salient features from the host signal that have been embedded into the host signal according to the method of claim 28 , and for comparing the decoded locations with locations of features in the host signal to determine authenticity of the host signal.
Claim 35
Dependent Claim 17 words
An object carrying an image that has been processed according to the method of claim 28 .
Claim 36
Independent Claim 131 words
A method for authenticating a media object comprising: transforming a media signal to a frequency domain comprising an array of frequency coefficients; selecting a first set of frequency coefficients; altering the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern; wherein the pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern; for each coefficient in the first set, selecting a corresponding coefficient in a corresponding set, and changing values of the coefficients in the first set and the corresponding coefficients in the corresponding set such that the differences between the coefficient values in the first set and the corresponding set form a desired delta pattern.
Claim 37
Independent Claim 131 words
A method for authenticating a media object comprising: transforming a media signal to a frequency domain comprising an array of frequency coefficients; selecting a first set of frequency coefficients; altering the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern; wherein the pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern; for each coefficient in the first set, selecting a corresponding coefficient in a corresponding set, and changing values of the coefficients in the first set and the corresponding coefficients in the corresponding set such that the differences between the coefficient values in the first set and the corresponding set form a desired delta pattern.
Claim 38
Dependent Claim 19 words
A decoder for decoding the pattern from a media signal that has been processed according to claim 32 .
Claim 39
Dependent Claim 17 words
An object carrying an image that has been processed according to the method of claim 32 .
Claim 40
Independent Claim 71 words
A method of encoding a plural symbol auxiliary message into content, comprising: (a) processing received input content to yield characteristic information related thereto; (b) defining a plural symbol auxiliary message that includes said characteristic information yielded from the input content; (c) performing an algorithmic transformation on said plural symbol auxiliary message to yield a watermark signal; and (d) processing the input content to steganographically convey the watermark signal, yielding encoded content.
Claim 41
Independent Claim 71 words
A method of encoding a plural symbol auxiliary message into content, comprising: (a) processing received input content to yield characteristic information related thereto; (b) defining a plural symbol auxiliary message that includes said characteristic information yielded from the input content; (c) performing an algorithmic transformation on said plural symbol auxiliary message to yield a watermark signal; and (d) processing the input content to steganographically convey the watermark signal, yielding encoded content.
Claim 42
Dependent Claim 38 words
The method of claim 35 wherein: said input content includes a text portion and an image portion; said characteristic information is derived from the text portion; and said processing comprises embedding the watermark signal in said image portion.
Claim 43
Dependent Claim 43 words
The method of claim 35 wherein: said input content includes a first portion, and a second portion distinct from said first portion; said characteristic information is based on the first portion; and said processing comprises embedding the watermark signal in said second portion.
Claim 44
Dependent Claim 28 words
The method of claim 35 wherein (d) includes locally adapting the strength of the watermark signal in accordance with local attributes of the input content, to enhance imperceptibility.
Claim 45
Dependent Claim 24 words
The method of claim 35 wherein (d) includes embedding the watermark signal substantially throughout the input content, rather than only in isolated portions thereof.
Claim 46
Dependent Claim 24 words
The method of claim 35 wherein said encoded content represents image information, and the method further includes printing said encoded content on a substrate.
Claim 47
Dependent Claim 12 words
A printed document produced according to the method of claim 40 .
Claim 48
Dependent Claim 52 words
In a method of digitally watermarking content, the method including performing an algorithmic transformation on a plural symbol auxiliary message to yield a watermark signal, and altering the content in accordance with said watermark signal, an improvement comprising deriving at least certain symbols of said auxiliary message from data representing the content.
Claim 49
Dependent Claim 52 words
In a method of digitally watermarking content, the method including performing an algorithmic transformation on a plural symbol auxiliary message to yield a watermark signal, and altering the content in accordance with said watermark signal, an improvement comprising deriving at least certain symbols of said auxiliary message from data representing the content.
Claim 50
Dependent Claim 11 words
The method of claim 42 wherein said content comprises graphic indicia.
Claim 51
Dependent Claim 46 words
The method of claim 42 wherein the content comprises plural samples, and the method includes: deriving at least certain symbols of said auxiliary message from a first set of said samples; and altering a second, different set of said samples in accordance with the watermark signal.
Claim 52
Dependent Claim 12 words
A document having content digitally watermarked according to claim 42 printed thereon.

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3.5 Years (Year 4) 2011-09-09 2012-03-10 2012-09-09 $2000.00 Window Closed / Lapsed
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