US6512837B1
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Watermarks carrying content dependent signal metrics for detecting and characterizing signal alteration
Assignee: Digimarc Corp
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Filing: 2000-10-11
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Granted: 2003-01-28
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Expires: 2020-10-11
Abstract
Abstract The invention provides methods and systems for detecting and characterizing alterations of media content, such as images, video and audio signals, using watermark messages to carry signal metrics. By comparing signal metrics extracted from the watermark to signal metrics calculated from a suspect signal, a watermark decoder can detect and even classify types of alterations to the watermarked signal.
Inventors
- 👤 Farid Ahmed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:10
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/005; G06T1/0064; G06T1/0028; H; H04; H04N; H04N1/00; H04N1/00002; H04N1/00005; H04N1/00026; H04N1/00037; H04N1/00039; H04N1/00045; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32203; H04N1/32229; H04N1/32288; G06T2201/00; G06T2201/005; G06T2201/0061
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
89 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein results of comparing the signal metrics are used to characterize a type of alteration based on a model that maps signal metric changes to alteration types.
Claim 2
Independent Claim
89 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein results of comparing the signal metrics are used to characterize a type of alteration based on a model that maps signal metric changes to alteration types.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the media signal is an image signal.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein signal metrics are computed for blocks of the media signal such that each block has two or more corresponding signal metrics.
Claim 5
Dependent Claim
18 words
The method of claim 3 wherein the signal metrics are computed from and embedded into the same blocks.
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein there are at least three metrics, and one metric is a function of two other metrics.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein at least one metric is computed based on edge information in a block of the media signal.
Claim 8
Dependent Claim
27 words
The method of claim 6 wherein the media signal comprises an image signal, and at least one metric is compute based on horizontal and vertical edge information.
Claim 9
Dependent Claim
14 words
A computer readable medium having software for performing the method of claim 1 .
Claim 10
Independent Claim
79 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein at least one metric is computed based on differences between adjacent blocks of the media signal.
Claim 11
Independent Claim
79 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein at least one metric is computed based on differences between adjacent blocks of the media signal.
Claim 12
Independent Claim
93 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein a first metric is a function of media signal data in a block, and a second metric is a function of differences between the media signal data of adjacent blocks.
Claim 13
Independent Claim
93 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein a first metric is a function of media signal data in a block, and a second metric is a function of differences between the media signal data of adjacent blocks.
Claim 14
Dependent Claim
18 words
The method of claim 10 wherein a third metric is a function of the first and second metrics.
Claim 15
Independent Claim
88 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein the metrics include horizontal and vertical edge information metrics, and a change in the horizontal and vertical edge information metrics is used to detect copying.
Claim 16
Independent Claim
88 words
A method of detecting alteration of a watermarked media signal comprising: dividing the watermarked media signal into blocks; decoding watermark signals from the blocks; extracting signal metrics from the watermark signals decoded from the blocks; comparing the signal metrics with corresponding signal metrics computed from the watermarked media signal, wherein a difference between the computed and extracted signal metrics evidences signal alteration; wherein the metrics include horizontal and vertical edge information metrics, and a change in the horizontal and vertical edge information metrics is used to detect copying.
Claim 17
Independent Claim
100 words
A method for embedding auxiliary information into a media signal for detecting alteration of the media signal, the method comprising: calculating two or more signal metrics of the media signal; and performing a watermark embedding process to embed the signal metrics into the media signal, such that the signal metrics are within an acceptable tolerance when computed from the media signal before and after the watermark embedding process; wherein the signal metrics are selected to detect particular types of alteration and are part of parametric model that classifies the particular types of alteration as a function of the signal metrics.
Claim 18
Independent Claim
100 words
A method for embedding auxiliary information into a media signal for detecting alteration of the media signal, the method comprising: calculating two or more signal metrics of the media signal; and performing a watermark embedding process to embed the signal metrics into the media signal, such that the signal metrics are within an acceptable tolerance when computed from the media signal before and after the watermark embedding process; wherein the signal metrics are selected to detect particular types of alteration and are part of parametric model that classifies the particular types of alteration as a function of the signal metrics.
Claim 19
Dependent Claim
34 words
The method of claim 13 including computing the metrics for each of block of a set of blocks of the media signal, and encoding the signal metrics for each block into the media signal.
Claim 20
Dependent Claim
20 words
The method of claim 14 wherein the signal metrics are embedded into the same blocks from which they are derived.
Claim 21
Dependent Claim
20 words
The method of claim 13 wherein one of the signal metrics is based on edge information of the media signal.
Claim 22
Dependent Claim
14 words
A computer readable medium having software for performing the method of claim 15 .
Claim 23
Independent Claim
94 words
A method for embedding auxiliary information into a media signal for detecting alteration of the media signal, the method comprising: calculating two or more signal metrics of the media signal; and performing a watermark embedding process to embed the signal metrics into the media signal, such that the signal metrics are within an acceptable tolerance when computed from the media signal before and after the watermark embedding process; wherein the signal metrics include a signal metric derived from differences between adjacent blocks of the media signal and embedded into one of the adjacent blocks.
Claim 24
Independent Claim
94 words
A method for embedding auxiliary information into a media signal for detecting alteration of the media signal, the method comprising: calculating two or more signal metrics of the media signal; and performing a watermark embedding process to embed the signal metrics into the media signal, such that the signal metrics are within an acceptable tolerance when computed from the media signal before and after the watermark embedding process; wherein the signal metrics include a signal metric derived from differences between adjacent blocks of the media signal and embedded into one of the adjacent blocks.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2006-01-27 | 2006-07-29 | 2007-01-28 | $2000.00 | Window Closed / Lapsed |
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