Wavelet domain watermarks
AssigneeDigimarc Corporation
InventorsRavi K. Sharma, Adnan M. Alattar, Farid Ahmed, Geoffrey B. Rhoads
Life of this patent
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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.
Claims27
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.
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.
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:
- 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.
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.
Dependencies are inferred from the claim text.