Method and apparatus for embedding watermarks

• US 7,460,684 B2
• Filed: 12/09/2005
• Issued: 12/02/2008
• Est. Priority Date: 06/13/2003
• Status: Active Grant

• Current Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Original Assignee: Nielsen Media Research, Inc. (Nielsen Holdings plc)
• Inventors: Srinivasan, Venugopal
• Primary Examiner(s): Tabatabai; Abolfazl
• Application Number:
  US11/298,040
• Publication Number:
  US 20070300066A1
• Time in Patent Office: 1,089 Days
• Field of Search: 382/100, 382/232, 382/240, 382/233, 382/243, 382/244, 370522-529, 713/176, 713/179, 380/51, 380/54, 380/201, 380/210, 380/252, 380/287, 283/72, 283 74- 81, 283/93, 283/113, 283/901, 283/902, 700/94
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G10L 19/0212 using orthogonal transformation
• CPC Class Codes: G10L 25/27 characterised by the analysis technique

Abstract

Methods and apparatus for embedding a watermark are disclosed. In an example method, one or more frames associated with a compressed digital data stream (240) is identified. Each of the one or more frames is unpacked to determine a plurality of transform coefficient sets (320). The plurality of transform coefficient sets (320) is modified to embed the watermark (230).

Claims

1. A method of embedding a watermark comprising:

identifying one or more frames associated with a compressed digital data stream;

unpacking each of the one or more frames to identify a plurality of transform coefficient sets; and

modifying the plurality of transform coefficient sets to embed the watermark by;

determining a mantissa code associated with a watermarked transform coefficient of one of a plurality of watermarked transform coefficient sets; and

substituting the mantissa code associated with the watermarked transform coefficient for a mantissa code associated with a corresponding transform coefficient of one of the plurality of transform coefficient sets.

2. A method as defined in claim 1, wherein modifying the plurality of transform coefficient sets comprises substituting a watermarked transform coefficient set for at least one of the plurality of transform coefficient sets.

3. A method as defined in claim 1, wherein determining the mantissa code associated with the watermarked transform coefficient of the one of the plurality of watermarked transform coefficient sets comprises:

selecting a code signal frequency to encode to the plurality of transform coefficient sets based on data to be embedded;

determining a masking energy associated with the code signal frequency to be encoded to the plurality of transform coefficient sets;

selecting a magnitude for the watermarked transform coefficient based on the masking energy; and

determining the mantissa code associated with the watermarked transform coefficient based on the magnitude.

4. A method as defined in claim 3, wherein the code signal frequency comprises a frequency corresponding to one of a plurality of high resolution frequency domain representations.

5. A method as defined in claim 3, wherein the code signal comprises one or more sinusoidal components, and wherein each sinusoidal component has a frequency based on a desired code.

6. A method as defined in claim 1, wherein modifying the plurality of transform coefficient sets comprises:

generating a plurality of time-domain audio blocks based on the plurality of transform coefficient sets;

generating a plurality of reconstructed audio blocks based on the plurality of time-domain audio blocks; and

generating a plurality of watermarked audio blocks based on the plurality of reconstructed audio blocks.

7. A method as defined in claim 6, wherein generating the plurality of time-domain audio blocks comprises generating a first time-domain audio block and a second time-domain audio block associated with an original audio block.

8. A method as defined in claim 6, wherein generating the plurality of reconstructed audio blocks based on the plurality of time-domain audio blocks comprises generating a reconstructed time-domain audio block corresponding to an original audio block based on a first time-domain audio block and a second time-domain audio block.

9. A method as defined in claim 8, wherein generating the fieit-reconstructed time-domain audio block the first audio block based on the first time domain audio block and the second time domain audio block comprises adding the first and second time-domain audio blocks.

10. A method as defined in claim 6, wherein generating the plurality of watermarked audio blocks based on the plurality of reconstructed audio blocks comprises:

generating a modifiable time-domain audio block based on the plurality of reconstructed audio blocks; and

generating a first watermarked audio block and a second watermarked audio block based on the modifiable time-domain audio block and the watermark.

11. A method as defined in claim 10, wherein generating the modifiable time-domain audio block based on the plurality of reconstructed audio blocks comprises concatenating a first reconstructed audio block and a second reconstructed audio block to form a 512-sample audio block.

12. A method as defined in claim 1, wherein modifying the plurality of transform coefficient sets comprises modifying the plurality of transform coefficient sets based on the plurality of watermarked transform coefficient sets.

13. A method as defined in claim 1, wherein modifying the plurality of transform coefficient sets comprises generating the plurality of watermarked transformed coefficient sets based on a first watermarked audio block and a second watermarked audio block.

14. A method as defined in claim 13, wherein generating the plurality of watermarked coefficient sets based on the first and second watermarked audio blocks comprises determining a respective mantissa code associated with at least one watermarked transform coefficient of each of the plurality watermarked transform coefficient sets based on compression information associated with the compressed digital data stream.

15. A method as defined in claim 1, wherein each of the plurality of transform coefficient sets comprises one or more modified discrete cosine transform coefficients.

16. A method as defined in claim 1, wherein the compressed digital data stream is compressed in accordance with an audio compression standard.

17. A method as defined in claim 1, wherein identifying the one or more frames associated with the compressed digital data stream comprises identifying audio blocks associated with at least one of a plurality of audio channels.

18. A method as defined in claim 1, wherein unpacking each of the one or more frames to identify the plurality of transform coefficient sets comprises identifying compression information associated with the compressed digital data stream.

19. A method as defined in claim 1 further comprising repacking the one or more frames base4-en-a-based on the plurality of watermarked transform coefficient sets.

20. A method as defined in claim 1, wherein the watermark is associated with one of a media source and a media program.

21. An apparatus for embedding a watermark comprising:

an identifier to identify one or more frames associated with a compressed digital data stream;

an unpacker to unpack each of the one or more frames to identifying a plurality of transform coefficient sets; and

a modifier to determine a mantissa code associated with a watermarked transform coefficient of one of a plurality of watermarked transform coefficient sets and to substitute the mantissa code associated with the watermarked transform coefficient for a mantissa code associated with a corresponding transform coefficient of one of the plurality of transform coefficient sets to modify the plurality of transform coefficient sets to embed the watermark.

22. An apparatus as defined in claim 21, wherein the modifier selects a code signal frequency to encode to the plurality of transform coefficient sets based on data to be embedded, determines a masking energy associated with the code signal frequency to be encoded to the plurality of transform coefficient sets, selects a magnitude for the watermarked transform coefficient based on the masking energy, and determines the mantissa code associated with the watermarked transform coefficient based on the magnitude.

23. An apparatus as defined in claim 22, wherein the code signal frequency comprises a frequency corresponding to one of a plurality of high resolution frequency domain representations.

24. An apparatus as defined in claim 22, wherein the code signal frequency comprises one or more sinusoidal components, and wherein each sinusoidal component has a frequency based on a desired code.

25. An apparatus as defined in claim 21, wherein the modifier generates a plurality of time-domain audio blocks, generates a plurality of reconstructed audio blocks based on the plurality of time-domain audio blocks, and generates a plurality of watermarked audio blocks based on the plurality of reconstructed audio blocks.

26. An apparatus as defined in claim 25, wherein the modifier generates a first time-domain audio block and a second time-domain audio block associated with an original audio block.

27. An apparatus as defined in claim 25, wherein the modifier generates a reconstructed time-domain audio block corresponding to an original audio block based on a first time-domain audio block and a second time-domain audio block.

28. An apparatus as defined in claim 27, wherein the modifier adds the first and second time-domain audio blocks.

29. An apparatus as defined in claim 25, wherein the modifier generates a modifiable time-domain audio block based on the plurality of reconstructed audio blocks, and generates a first watermarked audio block and a second watermarked audio block based on the modifiable time-domain audio block and the watermark.

30. An apparatus as defined in claim 29, wherein the modifier concatenates a first reconstructed audio block and a second reconstructed audio block to form a 512-sample audio block.

31. An apparatus as defined in claim 30, wherein the modifier determines a respective mantissa code associated with each watermarked coefficient of at least one of the plurality watermarked coefficient sets based on compression information of the compressed digital data stream.

32. An apparatus as defined in claim 21, wherein the modifier modifies the plurality of transform coefficient sets based based on the plurality of watermarked transform coefficient sets.

33. An apparatus as defined in claim 32, wherein the modifier generates one of the plurality of watermarked transform coefficient sets based on a first watermarked audio block and a second watermarked audio block.

34. An apparatus as defined in claim 32, wherein the modifier substitutes one of the plurality of watermarked transform coefficient sets for one of the plurality of transform coefficient sets.

35. An apparatus as defined in claim 21, wherein each of the plurality of transform coefficient sets comprises one or more modified discrete cosine transform coefficients.

36. An apparatus as defined in claim 21, wherein the compressed digital data stream is compressed in accordance with an audio compression standard.

37. An apparatus as defined in claim 21, wherein the identifying unit identifies audio blocks associated with a plurality of audio channels.

38. An apparatus as defined in claim 21, wherein the unpacking unit identifies compression information associated with the compressed digital data stream.

39. An apparatus as defined in claim 21, wherein the watermark comprises a watermark associated with one of a media source and a media program.

40. An apparatus as defined in claim 21 further comprising a frame repacker to repack the one or more frames based on the plurality of watermarked transform coefficient sets.

41. A computer accessible medium storing computer readable instructions, which when executed, cause a computer to:

identify one or more frames associated with a compressed digital data stream;

unpack each of the one or more frames to identify a plurality of transform coefficient sets; and

modify the plurality of transform coefficient sets to embed a watermar by;

determining a mantissa code associated with a watermarked transform coefficient of one of a plurality of watermarked transform coefficient sets; and

substituting the mantissa code associated with the watermarked transform coefficient for a mantissa code associated with a corresponding transform coefficient of one of the plurality of transform coefficient sets.

42. A computer accessible medium as defined in claim 41, wherein the instructions, which when executed, cause the computer to modify the plurality of transform coefficient sets by substituting at least one of the watermarked transform coefficient sets for at least one of the plurality of transform coefficient sets.

43. A computer accessible medium as defined in claim 41, wherein the instructions, which when executed, cause the computer to determine the mantissa code associated with the watermarked transform coefficient of the one of the plurality of watermarked transform coefficient sets by:

selecting a code signal frequency to encode to the plurality of transform coefficient sets based on data to be embedded;

determining a masking energy associated with the code signal frequency to be encoded to the plurality of transform coefficient sets;

selecting a magnitude for the watermarked transform coefficient based on the masking energy; and

determining the mantissa code associated with the watermarked transform coefficient based on the magnitude.

44. A computer accessible medium as defined in claim 43, wherein the code signal frequency comprises a frequency corresponding to one of a plurality of high resolution frequency domain representations.

45. A computer accessible medium as defined in claim 43, wherein the code signal frequency comprises one or more sinusoidal components, and wherein each sinusoidal component has a frequency based on a desired code.

46. A computer accessible medium as defined in claim 41, wherein the instructions, which when executed, cause the computer to modify the plurality of transform coefficient sets by:

generating a plurality of time-domain audio blocks based on the plurality of transform coefficient sets;

generating a plurality of reconstructed audio blocks based on the plurality of time-domain audio blocks; and

generating a plurality of watermarked audio blocks based on the plurality of reconstructed audio blocks.

47. A computer accessible medium as defined in claim 46, wherein the instructions, which when executed, cause the computer to generate the plurality of time-domain audio blocks by generating a first time-domain audio block and a second time-domain audio block associated with an original audio block.

48. A computer accessible medium as defined in claim 46, wherein the instructions, which when executed, cause the computer to generate a reconstructed time-domain audio block corresponding to an original audio block based on a first time-domain audio block and a second time-domain audio block.

49. A computer accessible medium as defined in claim 48, wherein the instructions, which when executed, cause the computer to generate the reconstructed time-domain audio block corresponding to the original audio block bby adding the first and second time-domain audio blocks.

50. A computer accessible medium as defined in claim 46, wherein the instructions, which when executed, cause the computer to generate the plurality of watermarked audio blocks by:

generating a modifiable time-domain audio block based on the plurality of reconstructed audio blocks; and

generating a first watermarked audio block and a second watermarked audio block based on the modifiable time-domain audio block and the watermark.

51. A computer accessible medium as defined in claim 50, wherein the instructions, which when executed, cause the computer to generate the modifiable time-domain audio block by concatenating a first reconstructed audio block and a second reconstructed audio block to form a 512-sample audio block.

52. A computer accessible medium as defined in claim 46, wherein the instructions, which when executed, cause the computer to generate one of a one of the plurality of watermarked transform coefficient sets based on a first watermarked audio block and a second watermarked audio block.

53. A computer accessible medium as defined in claim 52, wherein the instructions, which when executed, cause the computer to generate the one of the plurality of watermarked coefficient sets by determining a mantissa code associated with each watermarked transform coefficient of the one of the plurality watermarked coefficient sets based on compression information associated with the compressed digital data stream.

54. A computer accessible medium as defined in claim 41, wherein each of the plurality of transform coefficient sets comprises one or more modified discrete cosine transform coefficients.

55. A computer accessible medium as defined in claim 41, wherein the compressed digital data stream is compressed in accordance with an audio compression standard.

56. A computer accessible medium as defined in claim 41, wherein the instructions, which when executed, cause the computer to identify the one or more frames associated with the compressed digital data stream by identifying audio blocks associated with at least one of a plurality of audio channels.

57. A computer accessible medium as defined in claim 41, wherein the instructions cause the computer to unpack each of the one or more frames to identify the plurality of transform coefficient sets by identifying compression information associated with the compressed digital data stream.

58. A computer accessible medium as defined in claim 41, wherein the instructions, which when executed, cause the computer to repack the one or more frames based on the plurality of watermarked transform coefficient sets.

59. A computer accessible medium as defined in claim 41, wherein the watermark is associated with one of a media source and a media program.

60. A computer accessible medium as defined in claim 41 comprising one of a programmable gate array, application specific integrated circuit, erasable programmable read only memory, read only memory, random access memory, magnetic media, and optical media.