Methods, apparatus and systems for an electronic watermark having resistance to scaling
First Claim
1. A method for performing an electronic watermark on digital data, comprising the steps of:
- preparing a digital embedded pattern having information that is to be embedded as an electronic watermark in digital data; and
embedding said embedded pattern in said digital data at least twice or more repeatedly;
wherein said embedded pattern has a tuple of base block patterns that are orthogonal to each other and has a repetitive pattern in the horizontal and/or vertical direction, and wherein the step of embedding employs a known repetition rate.
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Abstract
The present invention provides methods, apparatus and systems for embedding and detecting an electronic watermark without requiring signals for geometric compensation. A particular embodiment uses a periodic pattern with repetition as an embedded pattern itself, which has information embedded as an electronic watermark, and observes the change of its period upon detection to calculate the scaling factor. When detecting the electronic watermark, the scaling factor of images is calculated from digital data that underwent the scaling processing, and then the processing to detect the electronic watermark is performed based on the obtained scaling factor.
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Citations
26 Claims
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1. A method for performing an electronic watermark on digital data, comprising the steps of:
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preparing a digital embedded pattern having information that is to be embedded as an electronic watermark in digital data; and embedding said embedded pattern in said digital data at least twice or more repeatedly; wherein said embedded pattern has a tuple of base block patterns that are orthogonal to each other and has a repetitive pattern in the horizontal and/or vertical direction, and wherein the step of embedding employs a known repetition rate. - View Dependent Claims (2, 3, 4, 11)
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5. A method for detecting an electronic watermark embedded in digital data, comprising the steps of:
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when detecting an embedded pattern that has a tuple of base block patterns that are orthogonal to each other and has been embedded in digital data at least twice or more repeatedly, finding a period having a maximum correlation by autocorrelation of said embedded repetitive pattern; detecting a scaling factor added to a frame from a change of said period; and detecting said embedded pattern using said scaling factor employing the repetition rate of the embedded pattern. - View Dependent Claims (6, 7, 8, 9)
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10. A method for performing an electronic watermark on digital data composed of plural frames, comprising the steps of:
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preparing a digital embedded pattern having information that is to be embedded as an electronic watermark in digital data; and embedding said embedded pattern in one of said frames at least twice or more repeatedly; wherein said embedded pattern has tuple of base block patterns that are orthogonal to each other and has a repetitive pattern in the horizontal or vertical direction.
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12. A method for detecting an electronic watermark embedded in digital data composed of plural frames, comprising the steps of:
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when detecting an embedded pattern that has a tuple of base block patterns that are orthogonal to each other and has been embedded in one of said frames at least twice or more repeatedly, finding a period having a maximum correlation by autocorrelation of the pattern in said one frame; and detecting a scaling factor added to the frame from a change of said period. - View Dependent Claims (13)
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14. A method comprising:
- performing an electronic watermark on MPEG data composed of plural frames, wherein said MPEG data is divided into intra blocks of 8×
8 pixels in size and further performed DCT, including the steps of;preparing an embedded pattern having information that is to be embedded as an electronic watermark in said MPEG data, the embedded pattern being composed of a tuple of base block patterns of 8×
4 pixels in size that are orthogonal to each other; andembedding said embedded pattern in one of said frames at least twice or more repeatedly; wherein said embedded pattern has a repetitive pattern in the horizontal or vertical direction.
- performing an electronic watermark on MPEG data composed of plural frames, wherein said MPEG data is divided into intra blocks of 8×
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15. A method for performing an electronic watermark on compressed digital data, comprising the steps of:
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preparing a digital embedded pattern having information that is to be embedded as an electronic watermark in digital data; and embedding said embedded pattern in said digital data at least twice or more repeatedly; wherein said embedded pattern has a tuple of base block patterns that are orthogonal to each other and has a repetitive pattern in the horizontal or vertical direction, an autocorrelation peak of said repetitive pattern appearing differently when finding a scaling factor upon detection.
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16. A method for detecting an electronic watermark embedded in compressed digital data, comprising the steps of:
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when detecting an embedded pattern that has a tuple of base block patterns that are orthogonal to each other and has been embedded in digital data at least twice or more repeatedly, finding a period having a maximum correlation by autocorrelation of said embedded pattern; detecting a scaling factor added to the digital data from a change of said period; and detecting information embedded in the digital data by applying a shift pattern prepared in advance to a detected block. - View Dependent Claims (17)
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18. A system for performing an electronic watermark on digital data, comprising:
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means for preparing a digital embedded pattern having information that is to be embedded as an electronic watermark in digital data; and means for embedding said embedded pattern in said digital data at least twice or more repeatedly; wherein said embedded pattern has a tuple of base block patterns that are orthogonal to each other and has a repetitive pattern in the horizontal or vertical direction. - View Dependent Claims (19, 20)
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21. A system for detecting an electronic watermark embedded in digital data, comprising:
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when detecting an embedded pattern that has a tuple of base block patterns that are orthogonal to each other and has been embedded in digital data at least twice or more repeatedly, means for finding a period having a maximum correlation by autocorrelation of said embedded repetitive pattern; means for detecting a scaling factor added to the digital data from a change of said period; and means for detecting said embedded pattern using said scaling factor. - View Dependent Claims (22, 23)
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24. A computer readable storage medium tangibly embodying a program to cause a computer to perform an electronic watermark on digital data, the program comprising:
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a function of preparing a digital embedded pattern having information that is to be embedded as an electronic watermark in digital data; and a function of embedding said embedded pattern in said digital data at least twice or more repeatedly; wherein said embedded pattern has a tuple of base block patterns that are orthogonal to each other and has a repetitive pattern in the horizontal or vertical direction.
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25. A computer readable storage medium tangibly embodying a program to cause a computer to detect an electronic watermark embedded in digital data, the program comprising:
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when detecting an embedded pattern that has a tuple of base block patterns that are orthogonal to each other and has been embedded in digital data at least twice or more repeatedly, a function of finding a period having a maximum correlation by autocorrelation of said embedded repetitive pattern; a function of detecting a scaling factor added to a frame from a change of said period; and a function of detecting said embedded pattern using said scaling factor. - View Dependent Claims (26)
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Specification