Hybrid digital watermarking for video authentication

1. A hybrid digital watermarking system for video authentication, the system comprising:

an authenticated acquisition subsystem for digital watermarking video data;

a video management subsystem in signal communication with the authenticated acquisition subsystem for verifying the digital watermarked video data; and

signature means for applying a control signature to the video data,

wherein the signature means embeds signature bits into data blocks in accordance with a pseudo-random sequence that introduces a dependency among the blocks,

wherein the pseudo-random sequence is generated from a data-dependent seed extracted from at least one frame,

wherein the data-dependent seed is responsive to at least one DC coefficient, and

wherein the at least one DC coefficient is coarsely quantized prior to seed generation.

2. A system as defined in claim 1 wherein the video management subsystem is in intermittent signal communication with the authenticated acquisition subsystem.

3. A system as defined in claim 1 , the authenticated acquisition subsystem comprising a video imaging device for acquiring original video data.

4. A system as defined in claim 1 , the authenticated acquisition subsystem comprising a watermarking device for applying each of an identity signature and a control signature to the video data.

5. A system as defined in claim 4 wherein the control signature comprises fragile control bits and robust control bits.

6. A system as defined in claim 4 wherein the identity signature and the control signature are applied to the video data concurrent with real-time acquisition of the video data.

7. A system as defined in claim 4 wherein the identity signature and the control signature are embodied in a single hybrid digital watermark.

8. A system as defined in claim 7 wherein the single hybrid digital watermark achieves progressively varying robustness in a single watermark by means of at least one of error-correcting signature coding and rate-distortion guided bit embedding.

9. A system as defined in claim 1 , the video management subsystem comprising a verification device for verifying a control signature and an identity signature.

10. A system as defined in claim 9 wherein the identity signature and the control signature are extracted from a single digital watermark.

11. A system as defined in claim 1 , the video management subsystem comprising a watermark verifying playback device for verifying a control signature and an identity signature and displaying verified video data.

12. A system as defined in claim 11 wherein the watermark verifying playback device alerts a user to the presence of altered video content.

13. A hybrid digital watermarking system for video authentication as defined in claim 1 , the system further comprising watermark means for digitally watermarking the video data.

14. A system as defined in claim 13 , further comprising verification means in signal communication with the watermark means for verifying the digitally watermarked video data.

15. A system as defined in claim 14 , further comprising transmission means for intermittently transmitting the digitally watermarked video data prior to verification.

16. A system as defined in claim 14 , further comprising compression means for compressing the digitally watermarked video data prior to verification.

17. A system as defined in claim 16 wherein the compression means comprises encoding means for Moving Pictures Expert Group (“MPEG”) encoding the digitally watermarked video data prior to verification.

18. A system as defined in claim 17 wherein the encoding means comprises MPEG-2 encoder means for encoding the digitally watermarked video data prior to verification.

19. A system as defined in claim 17 wherein the encoding means comprises MPEG-4 encoder means for encoding the digitally watermarked video data prior to verification.

20. A system as defined in claim 14 , further comprising imaging means for acquiring original video data.

21. A system as defined in claim 20 wherein the imaging means acquires original video data in Digital Video (“DV”) format.

22. A system as defined in claim 14 , further comprising signature means for applying each of an identity signature and a control signature to the video data.

23. A system as defined in claim 22 wherein the signature means applies the identity signature and the control signature to the video data concurrent with real-time acquisition of the video data.

24. A system as defined in claim 22 wherein the signature means is in signal communication with the watermark means for combining the identity signature and the control signature in a single hybrid digital watermark.

25. A system as defined in claim 24 , further comprising at least one of:

coding means for coding error-correcting signatures in the single hybrid digital watermark; and

embedding means in signal communication with the encoding means for embedding rate-distortion guided bits in the single hybrid digital watermark to achieve progressively varying robustness.

26. A system as defined in claim 24 , further comprising verification means for verifying a control signature and an identity signature.

27. A system as defined in claim 26 wherein the verification means extracts the identity signature and the control signature from a single digital watermark.

28. A system as defined in claim 24 , further comprising:

signature verification means for verifying at least one of a control signature and an identity signature; and

display means in signal communication with the signature verification means for displaying verified video data.

29. A system as defined in claim 28 , further comprising alert means for producing an alert responsive to the presence of altered video content.

30. A system as defined in claim 16 , the verification means comprising tamper detection means responsive to knowledge specific to the compression domain.

31. A system as defined in claim 30 wherein the compression domain comprises DCT encoded data.

32. A system as defined in claim 30 wherein the knowledge specific to the compression domain comprises at least one of spatial and temporal dependencies.

33. A system as defined in claim 30 , further comprising:

likelihood means for assigning a likelihood value for possible tampering to each error block based its number of neighbors; and

temporal integration means for temporally integrating the likelihood values to compute a score map indicative of potentially tampered regions.

34. A system as defined in claim 22 wherein the signature means embeds signature bits into data blocks in accordance with a pseudo-random sequence that introduces a dependency among the blocks.

35. A system as defined in claim 34 wherein the pseudo-random sequence is generated from a data-dependent seed extracted from at least one frame.

36. A system as defined in claim 35 wherein the data-dependent seed for generating the pseudo-random sequence is itself generated using a hash function.

37. A system as defined in claim 36 wherein the data-dependent seed is responsive to at least one DC coefficient.

38. A system as defined in claim 37 wherein the at least one DC coefficient is coarsely quantized prior to seed generation.

39. A method of hybrid digital watermarking for video authentication, the method comprising:

digitally watermarking video data;

verifying the digitally watermarked video data;

applying a control signature to the video data;

embedding bits of the control signature into data blocks in accordance with a pseudo-random sequence that introduces a dependency among the blocks;

extracting a data-dependent seed from at least one frame, wherein the seed is responsive to at least one DC coefficient;

generating the pseudo-random sequence from the extracted data-dependent seed; and

applying a coarse quantizer to the at least one DC coefficient prior to seed generation.

40. A method as defined in claim 39 , further comprising intermittently transmitting the digitally watermarked video data prior to verification.

41. A method as defined in claim 39 , further comprising compressing the digitally watermarked video data prior to verification.

42. A method as defined in claim 41 wherein compressing comprises Moving Pictures Expert Group (“MPEG”) encoding the digitally watermarked video data prior to verification.

43. A method as defined in claim 42 wherein compressing comprises MPEG-2 encoding the digitally watermarked video data prior to verification.

44. A method as defined in claim 42 wherein compressing comprises MPEG-4 encoding the digitally watermarked video data prior to verification.

45. A method as defined in claim 39 , further comprising acquiring original video data.

46. A method as defined in claim 45 wherein the acquired original video data is in Digital Video (“DV”) format.

47. A method as defined in claim 39 , further comprising applying each of an identity signature and a control signature to the video data.

48. A method as defined in claim 47 wherein the control signature comprises fragile control bits and robust control bits.

49. A method as defined in claim 47 , further comprising embedding bits of the control signature into data blocks in accordance with a pseudo-random sequence that introduces a dependency among the blocks.

50. A method as defined in claim 49 , further comprising:

extracting a data-dependent seed from at least one frame; and generating the pseudo-random sequence from the extracted seed.

51. A method as defined in claim 50 , further comprising generating the seed for the pseudo-random sequence in accordance with a hash function.

52. A method as defined in claim 51 wherein the data-dependent seed is responsive to at least one DC coefficient.

53. A method as defined in claim 52 , further comprising applying a coarse quantizer to the at least one DC coefficient prior to seed generation.

54. A method as defined in claim 53 wherein the at least one DC coefficient is selected from a plurality of data blocks having a DC coefficient value close to a quantization level of the coarse quantizer.

55. A method as defined in claim 47 wherein the identity signature and the control signature are applied to the video data concurrent with real-time acquisition of the video data.

56. A method as defined in claim 47 wherein the identity signature and the control signature are embodied in a single hybrid digital watermark.

57. A method as defined in claim 56 , further comprising at least one of:

coding error-correcting signatures in the single hybrid digital watermark; and

embedding rate-distortion guided bits in the single hybrid digital watermark to achieve progressively varying robustness.

58. A method as defined in claim 39 , further comprising verifying a control signature and an identity signature.

59. A method as defined in claim 58 wherein the identity signature and the control signature are extracted from a single digital watermark.

60. A method as defined in claim 39 , further comprising:

verifying a control signature and an identity signature; and

displaying verified video data.

61. A method as defined in claim 60 , further comprising producing an alert responsive to the presence of altered video content.

62. A method as defined in claim 41 , further comprising detecting tampering in coordination with knowledge specific to the compression domain.

63. A method as defined in claim 62 wherein the compression domain comprises DCT encoded data.

64. A method as defined in claim 62 wherein the knowledge specific to the compression domain comprises at least one of spatial and temporal dependencies.

65. A method as defined in claim 62 , further comprising:

assigning a likelihood value for possible tampering to each error block based its number of neighbors; and

temporally integrating the likelihood values to compute a score map indicative of potentially tampered regions.