US6681029B1
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Decoding steganographic messages embedded in media signals
Assignee: Digimarc Corp
•
Filing: 2000-07-06
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Granted: 2004-01-20
•
Expires: 2020-07-06
Abstract
Abstract A decoder process reads a message steganographically encoded in a composite signal. One decoding process operates on a potentially modified version of the composite signal. The message is comprised of one or more symbols, each being associated with predetermined signal characteristics. The decoding process correlates these predetermined signal characteristics with the potentially modified composite signal to decode message symbols. Another decoding process analyzes a potentially modified version of the composite signal to gather evidence of signal characteristic associated with a message symbol. Based on the evidence, it determines whether the message symbol is present in the potentially modified version of the composite signal. Yet another decoding process analyzes the composite signal to gather evidence of characteristics associated with the message symbols in the message. Based on the evidence, it estimates message symbols. It compares the estimated message symbols with one or more message symbols known to be included in the message to assess whether the composite signal has a valid message.
Inventors
- 👤 Geoffrey B. Rhoads
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:19
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/14; B; B42; B42D; B42D25/00; B42D25/20; B42D25/23; 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; G06K7/1404; G06K7/1408; G06K7/1417; 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; G06T1/005; G06T1/0057; G06V; G06V30/00; G06V30/40; G07; G07C; G07C9/00; G07C9/20; G07C9/22; G07C9/25; G07C9/253; G07D; G07D7/00; G07D7/003; G07D7/0032; G07D7/0034; G07D7/004; G07F; G07F17/00; G07F17/16; G07F17/26; G07F7/00; G07F7/08; G07F7/086; G07F7/10; G07F7/1008; G07F7/1016; G07F7/12; G10; G10L; G10L19/00; G10L19/018; G11; G11B; G11B20/00; G11B20/00086; G11B20/00094; G11B20/00166; G11B20/0021; G11B20/00884; G11B20/00891; H; H04; H04B; H04B1/00; H04B1/66; H04B1/665; H04N; H04N1/00; H04N1/00002; H04N1/00005; H04N1/00026; H04N1/00037; H04N1/00071; H04N1/00074; H04N1/00079; 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; H04N5/00; H04N5/76; H04N5/91; H04N5/913; G06K2019/06215; G06K2019/06253; G06T2201/00; G06T2201/005; G06T2201/0052; G06T2201/0065; G11B20/00115; G11B20/00181; H04N1/32106; H04N1/32122; H04N2005/91307; H04N2005/91321; H04N2005/91335; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3204; H04N2201/3205; H04N2201/3207; H04N2201/3225; H04N2201/3226; H04N2201/3233; H04N2201/3242; H04N2201/3249; H04N2201/3269; H04N2201/327; H04N2201/3271; H04N2201/3274; H04N2201/328; H04W; H04W4/00; H04W4/12
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
87 words
A method of decoding a message embedded into a host signal, where the message is encoded in a two-dimensional code signal inserted into the host signal to form a composite signal in which the code signal is hidden and symbols in the message have predetermined signal characteristics such that the code signal is substantially invisible in the host signal, the method comprising: receiving a potentially modified version of the composite signal; and correlating the predetermined signal characteristics with the potentially modified composite signal to decode message symbols.
Claim 2
Independent Claim
87 words
A method of decoding a message embedded into a host signal, where the message is encoded in a two-dimensional code signal inserted into the host signal to form a composite signal in which the code signal is hidden and symbols in the message have predetermined signal characteristics such that the code signal is substantially invisible in the host signal, the method comprising: receiving a potentially modified version of the composite signal; and correlating the predetermined signal characteristics with the potentially modified composite signal to decode message symbols.
Claim 3
Dependent Claim
45 words
The method of claim 1 including: correlating the predetermined signal characteristics with the potentially modified composite signal to compute a measure of correlation for a message symbol; and determining whether the message symbol is embedded in the composite signal based on the measure of correlation.
Claim 4
Dependent Claim
14 words
The method of claim 1 including: decoding the message without using the host signal.
Claim 5
Independent Claim
100 words
A method of decoding a message embedded into a host signal, where the message is encoded in a two-dimensional code signal inserted into the host signal to form a composite signal and symbols in the message have predetermined signal characteristics, the method comprising: receiving a potentially modified version of the composite signal; and correlating the predetermined signal characteristics with the potentially modified composite signal to decode message symbols; decoding the message without using the host signal; estimating at least portions of the host signal; and removing an estimate of at least portions of the host signal before decoding the message.
Claim 6
Independent Claim
100 words
A method of decoding a message embedded into a host signal, where the message is encoded in a two-dimensional code signal inserted into the host signal to form a composite signal and symbols in the message have predetermined signal characteristics, the method comprising: receiving a potentially modified version of the composite signal; and correlating the predetermined signal characteristics with the potentially modified composite signal to decode message symbols; decoding the message without using the host signal; estimating at least portions of the host signal; and removing an estimate of at least portions of the host signal before decoding the message.
Claim 7
Dependent Claim
24 words
The method of claim 4 including: estimating a host signal by computing a local average around discrete samples of the potentially modified composite signal.
Claim 8
Dependent Claim
28 words
The method of claim 3 including filtering the potentially modified composite signal to remove portions of the host signal; and decoding the message from the filtered composite signal.
Claim 9
Dependent Claim
27 words
The method of claim 1 wherein the host signal is a video signal and the message is encoded into two or more frames of the video signal.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein the host signal is an image signal.
Claim 11
Dependent Claim
33 words
The method of claim 1 wherein the code signal is adapted based on the host signal to make the code signal less perceptible to humans in an output form of the composite signal.
Claim 12
Dependent Claim
17 words
The method of claim 1 wherein the code signal is derived in part from the host signal.
Claim 13
Dependent Claim
22 words
The method of claim 1 wherein at least part of the decoded message is used to control processing of the composite signal.
Claim 14
Dependent Claim
21 words
The method of claim 11 wherein at least part of the decoded message controls a device that processes the composite signal.
Claim 15
Dependent Claim
28 words
The method of claim 11 wherein at least part of the decoded message is used to control copying, playback or recording of the composite signal in the device.
Claim 16
Dependent Claim
19 words
The method of claim 1 wherein at least part of the decoded message is output on an output device.
Claim 17
Dependent Claim
30 words
The method of claim 1 wherein at least part of the decoded message is an address or a reference to an address of a network resource on a computer network.
Claim 18
Dependent Claim
25 words
The method of claim 1 wherein at least part of the decoded message is a reference to a database storing information about the host signal.
Claim 19
Dependent Claim
21 words
The method of claim 1 including: correlating the predetermined signal characteristics with the potentially modified composite signal using a matched filter.
Claim 20
Dependent Claim
67 words
The method of claim 1 wherein the predetermined signal characteristic comprises a signal vector and including: correlating the signal vector with the potentially modified composite signal by computing a dot product between the signal vector and at least a portion of the potentially modified composite signal to produce a measure of correlation; and determining whether a message symbol has been encoded based on the measure of correlation.
Claim 21
Dependent Claim
15 words
The method of claim 18 wherein the dot product is computed in a spatial domain.
Claim 22
Dependent Claim
22 words
The method of claim 18 wherein the.signal vector is a predetermined noise signal associated with a message symbol or set of symbols.
Claim 23
Independent Claim
128 words
A method of decoding a message steganographically embedded into a host signal, where the message is embedded into the host signal to form a composite signal in which the message is substantially imperceptible by adjusting the host signal to encode a signal characteristic associated with a message symbol, the method comprising: analyzing a potentially modified version of the composite signal to gather evidence of the characteristic associated with the message symbol, including estimating a steganographic signal embedded in the composite signal by comparing samples of the composite signal with corresponding neighboring samples and deriving an estimate of the steganographic signal based on a result of the comparison; and based on the evidence, determining whether the message symbol is present in the potentially modified version of the composite signal.
Claim 24
Independent Claim
128 words
A method of decoding a message steganographically embedded into a host signal, where the message is embedded into the host signal to form a composite signal in which the message is substantially imperceptible by adjusting the host signal to encode a signal characteristic associated with a message symbol, the method comprising: analyzing a potentially modified version of the composite signal to gather evidence of the characteristic associated with the message symbol, including estimating a steganographic signal embedded in the composite signal by comparing samples of the composite signal with corresponding neighboring samples and deriving an estimate of the steganographic signal based on a result of the comparison; and based on the evidence, determining whether the message symbol is present in the potentially modified version of the composite signal.
Claim 25
Dependent Claim
33 words
The method of claim 21 wherein the evidence includes a measure of correlation and includes: correlating a signal characteristic associated with a message symbol with the potentially modified version of the composite signal.
Claim 26
Dependent Claim
93 words
The method of claim 21 wherein the message includes two or more symbols embedded into the host signal, each being associated with a distinct signal characteristic, and includes: analyzing a potentially modified version of the composite signal to gather evidence of the characteristics associated with the message symbols; based on the evidence, determining whether the message symbols are present in the potentially modified version of the composite signal; and reconstructing at least a portion of the message from message symbols determined to be present in the potentially modified version of the composite signal.
Claim 27
Dependent Claim
14 words
The method of claim 21 wherein the signal characteristic is a two-dimensional code signal.
Claim 28
Independent Claim
148 words
A method of decoding a message steganographically embedded into a host signal, where the message is embedded into the host signal to form a composite signal in which the message is substantially imperceptible by adjusting the host signal to encode signal characteristics associated with message symbols, the method comprising: analyzing a potentially modified version of the composite signal to gather evidence of the characteristics associated with the message symbols in the message, including estimating at least portions of the host signal, and removing an estimate of at least portions of the host signal to compute an estimate of steganographically embedded data; and based on the evidence, estimating message symbols in the steganographically embedded data; and comparing the estimated message symbols with one or more message symbols known to be included in the message to assess whether the potentially modified version of the composite signal has a valid message.
Claim 29
Independent Claim
148 words
A method of decoding a message steganographically embedded into a host signal, where the message is embedded into the host signal to form a composite signal in which the message is substantially imperceptible by adjusting the host signal to encode signal characteristics associated with message symbols, the method comprising: analyzing a potentially modified version of the composite signal to gather evidence of the characteristics associated with the message symbols in the message, including estimating at least portions of the host signal, and removing an estimate of at least portions of the host signal to compute an estimate of steganographically embedded data; and based on the evidence, estimating message symbols in the steganographically embedded data; and comparing the estimated message symbols with one or more message symbols known to be included in the message to assess whether the potentially modified version of the composite signal has a valid message.
Claim 30
Dependent Claim
22 words
The method of claim 25 wherein the message includes at least one known message symbol and one or more other message symbols.
Claim 31
Dependent Claim
36 words
The method of claim 25 wherein the host signal has two or more dimensions, and the message is embedded in the host signal so as to extend over two or more dimensions of the host signal.
Claim 32
Dependent Claim
37 words
The method of claim 1 comprising: estimating the two-dimensional code signal by comparing samples of the composite signal with corresponding neighboring samples and deriving an estimate of code signal elements based on a result of the comparison.
Claim 33
Dependent Claim
23 words
The method of claim 4 wherein the estimate of the host signal is used to compute an estimate of the two-dimensional code signal.
Claim 34
Dependent Claim
32 words
The method of claim 25 wherein the estimate of the steganographically embedded data is derived by comparing samples of the composite signal with corresponding samples of the estimate of the host signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-01-19 | 2007-07-21 | 2008-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-01-19 | 2011-07-21 | 2012-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-01-19 | 2015-07-21 | 2016-01-20 | $7700.00 | Window Closed / Lapsed |