Wavelet domain watermarks
First Claim
Patent Images
1. A method of encoding an auxiliary signal in a media signal comprising:
- performing a wavelet decomposition of the media signal into two or more levels of resolution, including an approximate level and one or more higher resolution levels;
modifying the approximate level to encode an auxiliary signal such that the modification is substantially imperceptible in an output form of the media signal;
wherein the auxiliary signal comprises a watermark orientation signal.
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Abstract
A wavelet domain watermark encoder and decoder embed and detect auxiliary signals in a media signal, such as a still image, video or audio signal. A watermark orientation signal is embedded in a wavelet decomposed signal to facilitate detection of the watermark in a geometrically distorted version of the embedded signal.
523 Citations
27 Claims
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1. A method of encoding an auxiliary signal in a media signal comprising:
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performing a wavelet decomposition of the media signal into two or more levels of resolution, including an approximate level and one or more higher resolution levels;
modifying the approximate level to encode an auxiliary signal such that the modification is substantially imperceptible in an output form of the media signal;
wherein the auxiliary signal comprises a watermark orientation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary information is substantially imperceptible in an output form of the media signal;
- the method comprising;
performing a wavelet decomposition of the media signal into two or more levels of resolution, including an approximate level and one or more higher resolution levels; and
detecting the auxiliary information from the approximate level;
wherein the auxiliary signal comprises a watermark orientation signal; and
further including;using the orientation signal to determine orientation of the auxiliary signal in the media signal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
performing correlation between a reference orientation signal and the approximate level of the media signal to determine orientation of the auxiliary signal.
- the method comprising;
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13. The method of claim 12 including:
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performing a log re-sampling of the approximate level; and
performing the correlation on the re-sampled media signal and log sampled version of the reference orientation signal.
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14. The method of claim 12 including:
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performing a polar re-sampling of the approximate level; and
performing the correlation on the re-sampled media signal and polar sampled version of the reference orientation signal.
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15. A computer readable medium having software for performing the method of claim 9.
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16. A method of embedding an auxiliary signal into a media signal so that the auxiliary signal is substantially imperceptible to a human in the embedded media signal, the method comprising:
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performing a wavelet decomposition of the media signal; and
embedding a watermark orientation signal into the wavelet decomposition, wherein the auxiliary signal includes the watermark orientation signal and the watermark orientation signal has attributes used to determine orientation of the auxiliary signal in a geometrically distorted version of the media signal. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary signal is substantially imperceptible in an output form of the media signal;
- the method comprising;
performing a wavelet decomposition of the media signal into two or more levels of resolution; and
correlating a reference watermark orientation signal with the wavelet decomposition of the media signal to determine orientation of the auxiliary signal in the media signal. - View Dependent Claims (23, 24, 25, 26, 27)
performing multi-level correlation between the reference watermark orientation signal and the wavelet decomposition.
- the method comprising;
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24. The method of claim 23 including:
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performing correlation at an initial low level of resolution of the wavelet decomposition; and
refining results of the correlation at least one higher level of resolution of the wavelet decomposition.
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25. The method of claim 22 including:
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performing correlation at subbands within a level of resolution of the wavelet decomposition;
and combining results of the correlations at the subbands.
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26. The method of claim 22 including:
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performing a polar resampling of at least one level of resolution; and
performing correlation on the resampled level of correlation.
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27. A computer readable medium including software for performing the method of claim 22.
Specification