Method and apparatus for recording and reproducing electronic watermark information, and recording medium
First Claim
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1. A method of recording electronic watermark information comprising the steps of:
- embedding electronic watermark information in a video signal at a minimal disturbance against said video signal; and
recording a reference signal which is inserted at a position different from the position of said electronic watermark information, wherein said reference signal is used to set a detection level used by a detector to detect said watermark information which has been embedded in said video signal.
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Abstract
When a video signal having electronic watermark information embedded therein is recorded on a recording medium, a reference signal is inserted in the video signal at a position different from a position of embedment of the electronic watermark information. The electronic watermark information is embedded in the video signal by alteration of a luminous value of a luminance signal included in the video signal. When the video signal is reproduced from the recording medium, a luminous value of the electronic watermark information is modified based on the reference signal.
145 Citations
13 Claims
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1. A method of recording electronic watermark information comprising the steps of:
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embedding electronic watermark information in a video signal at a minimal disturbance against said video signal; and
recording a reference signal which is inserted at a position different from the position of said electronic watermark information, wherein said reference signal is used to set a detection level used by a detector to detect said watermark information which has been embedded in said video signal. - View Dependent Claims (2, 3, 4)
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5. A method of recording and reproducing electronic watermark information comprising the steps of:
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embedding electronic watermark information in a video signal at a minimal disturbance against said video signal;
recording a reference signal which is inserted at a position different from the position of said electronic watermark information; and
reproducing said reference signal and modifying said electronic watermark information by using said reference signal, wherein said reference signal is used to set a detection level used by a detector to detect said watermark information which has been embedded in said video signal. - View Dependent Claims (6, 7)
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8. A method of reproducing electronic watermark information comprising the steps of:
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detecting a reference signal for detecting electronic watermark information from a recording medium on which a video signal, said electronic watermark information which is embedded in said video signal by the alteration of the luminous value of the luminance signal included in said video signal and said reference signal which is inserted at a position different from the position of embedment of said electronic watermark information are recorded, wherein said reference signal is used to set a detection level used during said detecting step to detect said watermark information which has been embedded in said video signal; and
modifying the luminous value of said electronic watermark information based on said reference signal.
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9. An apparatus for reproducing electronic watermark information comprising:
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an electronic watermark information detecting circuit which detects electronic watermark information from a video signal;
a reference signal detecting circuit which detects a reference signal; and
a modification circuit which modifies the amplitude of said electronic watermark information based on the amplitude of said reference signal, wherein said reference signal is used to set a detection level used by said electronic watermark information detecting circuit to detect said watermark information which has been embedded in said video signal. - View Dependent Claims (10, 11, 12, 13)
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Specification