Techniques and systems for embedding and detecting watermarks in digital data
First Claim
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1. A method for embedding a watermark in data, including a processor to perform the steps of:
- analysing the data to derive a transform matrix for extracting from the data amplitudes of statistically mutually independent components of the data;
encoding the data using the transform matrix;
classifying said components in accordance with their energies, into higher, lower and medium energy ranges;
selecting the components classified in said medium energy range;
modifying at least a portion of the selected components using a watermark pattern; and
decoding the data using an inverse of the transform matrix to obtain watermarked data in which the watermark pattern is embedded.
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Abstract
A method for embedding and detecting watermarks in digital data. Data is analysed by an independent component analysis to derive a transform matrix W encoding properties of the data. The data is encoded using this transform matrix W, and a watermark is embedded into it. Then the inverse of the transform matrix is applied to obtain watermarked data. The presence of the watermark is found by applying the transform matrix again, and examining the result for the presence of the watermark.
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Citations
36 Claims
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1. A method for embedding a watermark in data, including a processor to perform the steps of:
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analysing the data to derive a transform matrix for extracting from the data amplitudes of statistically mutually independent components of the data; encoding the data using the transform matrix; classifying said components in accordance with their energies, into higher, lower and medium energy ranges; selecting the components classified in said medium energy range; modifying at least a portion of the selected components using a watermark pattern; and decoding the data using an inverse of the transform matrix to obtain watermarked data in which the watermark pattern is embedded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for embedding a watermark in data, including a processor arranged to:
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analyse the data to derive a transform matrix for extracting from the data amplitudes of components of the data which are statistically mutually independent; encode the data using the transform matrix; classify said components in accordance with their energies, into higher, lower and medium energy ranges; select the components classified in said medium energy range; modify at least a portion of the selected components using a watermark pattern; and decode the data using an inverse of the transform matrix to obtain watermarked data in which the watermark pattern is embedded. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for embedding a watermark in data, including a processor to perform the steps of:
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analysing the data to derive a transform matrix for extracting from the data amplitudes of statistically mutually independent components of the data; encoding the data using the transform matrix; modifying at least a portion of the encoded data with a watermark pattern; and decoding the data using an inverse of the transform matrix to obtain watermarked data in which the watermark pattern is embedded, wherein the modified portion of the encoded data is selected by ordering the components by their amplitudes and selecting components having amplitudes within one or more amplitude ranges, and is further selected by ordering the components according to their main properties, and selecting components having similar parameters of the main properties, wherein the component main properties include spatial location, orientation and frequency magnitude.
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36. An apparatus for embedding a watermark in data, including a processor arranged to:
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analyse the data to derive a transform matrix for extracting from the data amplitudes of components of the data which are statistically mutually independent; encode the data using the transform matrix;
modify at least a portion of the encoded data using a watermark pattern; anddecode the data using an inverse of the transform matrix to obtain watermarked data in which the watermark pattem is embedded, wherein the modified portion of the encoded data is selected by ordering the components by their amplitudes and selecting components having amplitudes within one or more amplitude ranges, and is further selected by ordering the components according to their main properties, and selecting components having similar parameters of the main properties, wherein the component main properties include spatial location, orientation and frequency magnitude.
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Specification