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US 5,848,155 AGranted
Spread spectrum watermark for embedded signalling
AssigneeNEC Research Institute, Inc.
InventorIngemar J. Cox
Life of this patent
Estimating the term…
Abstract
A watermark is embedded into audio/video/image/multimedia data using spread spectrum methodology. The watermark is extracted from watermarked data without the use of an original or unwatermarked version of the data by using spatial or temporal local averaging of the frequency coefficients of the watermarked data.
Claims22
A method of extracting a watermark from watermarked data comprising the steps of:
- receiving watermarked data;
- spectrum normalizing the watermarked data to generate a normalized signal;
- correlating the normalized signal with predetermined PN sequences corresponding to predetermined symbols to provide correlated signals for each predetermined PN sequence;
- deciding which PN sequence is present in the watermarked data based upon said correlated signals;
- and
- extracting a watermark corresponding to a sequence of PN sequences present.
3 more elements
A method for inserting a watermark into data comprising the steps of:
- providing a watermark;
- providing a spectrum of the data;
- shaping the spectrum of the watermark commensurate with the average spectrum of the data;
- and
- combining the shaped spectrum watermark with the spectrum of the data to obtain watermarked data spectrum.
2 more elements
A method of inserting a watermark into data comprising the steps of:
- providing a watermark signal,
- providing a spectrum of the data;
- shaping the spectrum of the watermark signal to be commensurate with the spectrum of the data;
- and
- summing the shaped spectrum watermark signal with the spectrum of the data to obtain watermarked data spectrum.
2 more elements
Dependencies are inferred from the claim text.