Steganographic encoding and decoding of auxiliary codes in media signals
First Claim
1. A method of decoding an auxiliary code embedded in an audio signal, the method comprising:
- performing statistical decoding of a multibit auxiliary code embedded in an audio signal, where the auxiliary code has been repetitively embedded in the audio signal;
decoding code values of the auxiliary code from two or more different portions of the audio signal, each having the multibit auxiliary code;
wherein statistical features of portions of the audio signal have been modified according to statistical features associated with the code values to embed the code values in the audio signal;
using the code values decoded from the two or more different portions of the audio signal to determine statistically the code values of the auxiliary code.
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Abstract
One aspect of the invention is a method of decoding an auxiliary code embedded in an audio signal. The method performs a statistical decoding of a multibit auxiliary code embedded in an audio signal. The auxiliary code has been repetitively embedded in the audio signal. The method decodes code values of the auxiliary code from two or more different portions of the audio signal, each having the multibit auxiliary code. It then uses the code values decoded from two or more different portions to determine statistically the code values of the auxiliary code. Another aspect of the invention is another method of decoding an auxiliary code embedded in an audio signal. The method receives an audio signal suspected of being embedded with an auxiliary code. It evaluates a statistical feature of a portion of the audio signal to decode code values of the auxiliary code from the audio signal. It then determines a code value in the auxiliary code based on the statistical feature. The statistical feature may comprise, for example, the power of the audio signal. The statistical feature may be analyzed over different portions of the audio signal to decode two or more values of the auxiliary code.
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Citations
27 Claims
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1. A method of decoding an auxiliary code embedded in an audio signal, the method comprising:
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performing statistical decoding of a multibit auxiliary code embedded in an audio signal, where the auxiliary code has been repetitively embedded in the audio signal;
decoding code values of the auxiliary code from two or more different portions of the audio signal, each having the multibit auxiliary code;
wherein statistical features of portions of the audio signal have been modified according to statistical features associated with the code values to embed the code values in the audio signal;
using the code values decoded from the two or more different portions of the audio signal to determine statistically the code values of the auxiliary code. - View Dependent Claims (2, 5, 6, 7, 8, 9, 10, 11, 12)
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3. A method of decoding an auxiliary code embedded in an audio signal, the method comprising:
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performing statistical decoding of a multibit auxiliary code embedded in an audio signal, where the auxiliary code has been repetitively embedded in the audio signal;
decoding code values of the auxiliary code from two or more different portions of the audio signal, each having the multibit auxiliary code;
using the code values decoded from the two or more different portions of the audio signal to determine statistically the code values of the auxiliary code;
wherein a statistical feature of the audio signal is analyzed to decode the code values of the auxiliary code and wherein the statistical feature of the audio signal comprises entropy.
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4. A method of decoding an auxiliary code embedded in an audio signal, the method comprising:
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performing statistical decoding of a multibit auxiliary code embedded in an audio signal, where the auxiliary code has been repetitively embedded in the audio signal;
decoding code values of the auxiliary code from two or more different portions of the audio signal, each having the multibit auxiliary code;
using the code values decoded from the two or more different portions of the audio signal to determine statistically the code values of the auxiliary code;
wherein a statistical feature of the audio signal is analyzed to decode the code values of the auxiliary code and wherein the statistical feature of the audio signal comprises power.
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13. A computer readable medium on which is stored software for performing a method of decoding an auxiliary code embedded in an audio signal, the method comprising:
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performing statistical decoding of a multibit auxiliary code embedded in an audio signal, where the auxiliary code has been repetitively embedded in the audio signal;
decoding code values of the auxiliary code from two or more different portions of the audio signal, each having the multibit auxiliary code;
wherein statistical features of portions of the audio signal have been modified according to statistical features associated with the code values to embed the code values in the audio signal;
using the code values decoded from the two or more different portions of the audio signal to determine statistically the code values of the auxiliary code.
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14. A method of decoding an auxiliary code embedded in an audio signal, the method comprising:
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receiving an audio signal suspected of being embedded with an auxiliary code;
evaluating a statistical feature of a portion of the audio signal to decode code values of the auxiliary code from the audio signal; and
determining a code value in the auxiliary code based on the statistical feature;
wherein the statistical feature comprises power of the audio signal.
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15. A method of steganographically encoding a set of source data with a set of auxiliary data, each of said sets of data comprising a plurality of elements, the method including:
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(a) providing a carrier signal;
(b) processing elements of the carrier signal in accordance with a corresponding element of the set of auxiliary data to produce a processed datum, including scaling the processed datum as a function of the source data in a perceptual domain in which the source data is perceived by humans so as to make the processed datum adaptive to the source data in the perceptual domain;
(c) combining the processed datum with elements of said set of source data to produce an encoded datum, said combining including performing an addition operation between the processed data and said elements of source data;
(d) repeating steps (b) and (c) for other elements of the sets of auxiliary data and source data, thereby producing a set of encoded data;
including modulating a statistical characteristic of samples of the source data such that the resulting encoded source data has a statistical characteristic corresponding to a value of the auxiliary data element being encoded, and the auxiliary data element is decodable by measuring the statistical characteristic for elements of the encoded source data. - View Dependent Claims (16, 17)
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18. A method of steganographically encoding a set of source data with a set of auxiliary data, each of said sets of data comprising a plurality of elements, the method including:
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(a) providing a carrier signal;
(b) processing elements of the carrier signal in accordance with a corresponding element of the set of auxiliary data to produce a processed datum, including scaling the processed datum as a function of the source data in a perceptual domain in which the source data is perceived by humans so as to make the processed datum adaptive to the source data in the perceptual domain;
(c) combining the processed datum with elements of said set of source data to produce an encoded datum, said combining including performing an addition operation between the processed data and said elements of source data;
(d) repeating steps (b) and (c) for other elements of the sets of auxiliary data and source data, thereby producing a set of encoded data;
including modulating statistical characteristics of time domain samples of the source signal such that the auxiliary data is decoded by computing the statistical characteristics of the samples of the encoded source signal. - View Dependent Claims (19)
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20. A method of steganographically encoding a set of source data with a set of auxiliary data, each of said sets of data comprising a plurality of elements, the method including:
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providing a carrier signal;
processing elements of the carrier signal in accordance with corresponding elements of the set of auxiliary data to produce processed data sets;
combining the processed data sets with elements of said set of source data to produce encoded source data, including modulating a statistical characteristic of samples of the source data such that the resulting encoded source data has a statistical characteristic corresponding to a value of the auxiliary data element being encoded, and the auxiliary data element is decodable by measuring the statistical characteristic for elements of the encoded source data. - View Dependent Claims (21, 22, 25)
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23. A computer readable medium on which is stored instructions for performing a method of steganographically encoding a set of source data with a set of auxiliary data, each of said sets of data comprising a plurality of elements, the method including:
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providing a carrier signal;
processing elements of the carrier signal in accordance with corresponding elements of the set of auxiliary data to produce processed data sets;
combining the processed data sets with elements of said set of source data to produce encoded source data, including modulating a statistical characteristic of samples of the source data such that the resulting encoded source data has a statistical characteristic corresponding to a value of the auxiliary data element being encoded, and the auxiliary data element is decodable by measuring the statistical characteristic for elements of the encoded source data.
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24. A steganographic decoder operable to decode the encoded source data which has been encoded according to a method of steganographically encoding a set of source data with a set of auxiliary data, each of said sets of data comprising a plurality of elements, the method including:
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providing a carrier signal;
processing elements of the carrier signal in accordance with corresponding elements of the set of auxiliary data to produce processed data sets;
combining the processed data sets with elements of said set of source data to produce encoded source data, including modulating a statistical characteristic of samples of the source data such that the resulting encoded source data has a statistical characteristic corresponding to a value of the auxiliary data element being encoded, and the auxiliary data element is decodable by measuring the statistical characteristic for elements of the encoded source data.
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26. A method of steganographically encoding a set of source data with a set of auxiliary data, each of said sets of data comprising a plurality of elements, the method including:
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providing a transformation between auxiliary data elements and a code signal;
processing elements of the auxiliary data in accordance with the transformation to produce processed data sets;
combining the processed data sets with elements of said set of source data to produce encoded source data, including modulating a statistical characteristic of samples of the source data such that the resulting encoded source data has a statistical characteristic corresponding to a value of the auxiliary data element being encoded, and the auxiliary data element is decodable by measuring the statistical characteristic for elements of the encoded source data. - View Dependent Claims (27)
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Specification