Embedding a digital signature in a video sequence
First Claim
1. A method for embedding and retrieving information in a video signal, the method comprising the steps of:
- selecting a first subset and a second subset of the video signal;
determining a relationship between the first subset and the second subset of the video signal;
changing the relationship between the first subset and the second subset of the video signal, wherein the step of changing includes encoding the information into the video signal to produce a changed video signal having a changed relationship; and
detecting the changed relationship from the changed video signal and, from the detected changed relationship, retrieving the encoded information;
wherein the first subset belongs to one frame and the second subset belongs to a different frame of the video signal.
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Accused Products
Abstract
Method and apparatus for watermarking digital video material by embedding a digital signature. One embodiment of the system integrates the embedding procedure into a block-based compression scheme. In one embodiment, a 32-bit digital signature is embedded into the x- and y-coordinates of motion vectors. Since not all motion vectors are suitable for coding (with regard to objectionable visible artifacts), three hybrid selection criteria have been developed for determining whether or not to code a motion vector. A probabilistic coding procedure has also been developed to avoid problems that arise when fewer than 16 blocks and/or vectors (where 16 vectors correspond to 32 bits) can be coded in a frame. One such procedure makes use of binary random sequences to virtually code the signature into the motion vectors. The system has been implemented on a CRAY T3D massively parallel supercomputer, where a near-real-time (5 frames per second) embedding of the signature is obtainable. The results show that it is possible to embed and retrieve a 32-bit signature if enough blocks over time are selected.
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Citations
36 Claims
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1. A method for embedding and retrieving information in a video signal, the method comprising the steps of:
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selecting a first subset and a second subset of the video signal; determining a relationship between the first subset and the second subset of the video signal; changing the relationship between the first subset and the second subset of the video signal, wherein the step of changing includes encoding the information into the video signal to produce a changed video signal having a changed relationship; and detecting the changed relationship from the changed video signal and, from the detected changed relationship, retrieving the encoded information; wherein the first subset belongs to one frame and the second subset belongs to a different frame of the video signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for embedding digital information into a video signal such that the digital information can later be retrieved, the digital information including a plurality of bits, the system comprising:
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a selector that selects a first subset and a second subset of the video signal; a comparator that determines a relationship between the first subset and the second subset of the video signal; and a changer that changes the relationship between the first subset and the second subset of the video signal by encoding the information into the video signal to produce a changed video signal having a changed relationship; wherein the first subset belongs to one frame and the second subset belongs to a different frame of the video signal. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method for embedding a retrievable watermark into a video signal, the video signal providing a series of video frames including a first frame and a second frame, the method comprising the steps of:
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detecting a change between the first frame and the second frame; producing change information based on the change; and encoding the retrievable watermark into the change information.
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16. A method for embedding a retrievable watermark into a video signal, the video signal providing a series of video frames including a first frame and a second frame, the method comprising the steps of:
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detecting a change between the first frame and the second frame; producing change information based on the change; and encoding the watermark into the change information; wherein the step of encoding modifies a motion vector based on the watermark. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for embedding digital information into a video signal such that the digital information can later be retrieved;
- the digital information including a plurality of bits, the video signal providing a series of video frames including a first frame and a subsequent second frame, the first frame being subdivided into a plurality of blocks, the method comprising the steps of;
obtaining a motion vector for each one of a subset of the blocks in the first frame, each motion vector representative of a displacement between a block in the first frame and a corresponding block in the second frame; and modifying one or more of said motion vectors based on a value of one or more bits of said digital information such that the digital information can later be retrieved. - View Dependent Claims (26)
- the digital information including a plurality of bits, the video signal providing a series of video frames including a first frame and a subsequent second frame, the first frame being subdivided into a plurality of blocks, the method comprising the steps of;
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27. A method for embedding digital information into a video signal such that the digital information can later be retrieved;
- the digital information including a plurality of bits, the video signal providing a series of video frames including a first frame and a subsequent second frame, the first frame being subdivided into a plurality of blocks, the method comprising the steps of;
obtaining a motion vector for each one of a subset of the blocks in the first frame, each motion vector representative of a displacement between a block in the first frame and a corresponding block in the second frame; and modifying one or more of said motion vectors based on a value of one or more bits of said digital information; wherein the digital information includes a signature having a predefined bitset S(I), I=1, 2, . . . , L, where L is the number of bits in the signature, and wherein the step of modifying modifies a component of the motion vector based on one or more bits of said digital information.
- the digital information including a plurality of bits, the video signal providing a series of video frames including a first frame and a subsequent second frame, the first frame being subdivided into a plurality of blocks, the method comprising the steps of;
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28. A method for embedding digital information into a video signal, the video signal providing a series of video frames including a first frame and a subsequent second frame, the method comprising the steps of:
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detecting a motion between the first frame and the second frame; producing a motion vector set based on the motion; selecting change information that includes a suitable subset of the motion vector set that is suitable for coding; and encoding the digital information into the change information such that the digital information can later be retrieved. - View Dependent Claims (29)
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30. A watermarking system for embedding digital information into a video signal such that the digital information can later be retrieved;
- the digital information including a plurality of bits, the video signal providing a series of video frames including a first frame and a subsequent second frame, the first frame being subdivided into a plurality of blocks, the watermarking system comprising;
a block-based motion-estimation (BBME) coder, and wherein the BBME coder generates a motion vector for each one of a subset of the blocks in the first frame, each motion vector representative of a displacement between a block in the first frame and a corresponding block in the second frame; and a motion-vector modifier coupled to an output of the BBME coder that modifies one or more of said motion vectors based on a value of one or more bits of said digital information. - View Dependent Claims (31)
- the digital information including a plurality of bits, the video signal providing a series of video frames including a first frame and a subsequent second frame, the first frame being subdivided into a plurality of blocks, the watermarking system comprising;
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32. A storage medium having a computer program stored thereon for causing a suitably programmed system to embed information in a video signal by performing the following steps when such program is executed on the system:
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selecting a first subset and a second subset of the video signal; determining a relationship between the first subset and the second subset of the video signal; and changing the relationship between the first subset and the second subset of the video signal, wherein the step of changing includes encoding the information into the video signal to produce a changed video signal having a changed relationship; wherein the first subset belongs to one frame and the second subset belongs to a different frame of the video signal. - View Dependent Claims (33, 34, 35)
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36. A data structure for holding video information, the video information having embedded digital information such that the digital information can be retrieved from the video information, the digital information including a plurality of bits, the data structure comprising:
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a plurality of video frames, each frame being subdivided into a plurality of blocks; and a plurality of motion vectors, each one of said motion vectors associated with one block of a selected subset of the plurality of blocks, each motion vector representative of a displacement between a block in one frame and a corresponding block in a different frame, wherein the plurality of motion vectors has been modified based on a value of one or more bits of said digital information.
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Specification