Encoding and decoding auxiliary signals

• US 8,170,273 B2
• Filed: 04/27/2010
• Issued: 05/01/2012
• Est. Priority Date: 04/25/2001
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Sharma, Ravi K., Stach, John
• Primary Examiner(s): Azarian, Seyed
• Application Number:
  US12/768,519
• Publication Number:
  US 20100322468A1
• Time in Patent Office: 735 Days
• Field of Search: 382/100, 382/112, 382/162, 382/182, 382169-172, 382/191, 382232-235, 382/237, 382/242, 382/250, 382/260, 382/274, 382/284, 382/276, 382/294, 382/305, 382/236, 348/475, 360/77.08, 375/240.25, 380/54, 562/49
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain

Abstract

This disclosure describes apparatus and systems for encoding and decoding signals from a host signal such as audio, video or imagery. One claim recites an apparatus comprising: electronic memory for storing a media signal representing audio or video; and an electronic processor. The electronic processor is programmed for: extracting data representing at least some features of the media signal; using the extracted data as a key to select coefficients in a transform domain, the coefficients representing the media signal; and modifying selected coefficients to hide a steganographic signal in the media signal. Of course, other claims and combinations are provided as well.

Claims

1. An apparatus comprising:

electronic memory configured to store a media signal representing audio or video;

an electronic processor programmed for;

extracting a reduced-bit representation of the media signal;

adapting a digital watermark embedding process with the reduced-bit representation of the media signal; and

embedding a digital watermark in the media signal with the adapted digital watermark embedding process.

2. The apparatus of claim 1, wherein the watermark embedding process embeds at least a reference signal in the media signal that is used to correct or compensate for geometric distortion.

3. The apparatus of claim 2, wherein the reduced-bit representation is used to generate the reference signal.

4. The apparatus of claim 1, wherein the reduced-bit representation comprises a hash, and the embedding uses the hash as a key to encode a reference signal in data representing the media signal.

5. The apparatus of claim 1, wherein the media signal comprises an audio signal;

and wherein the reduced bit representation is used together with a key to compute the digital watermark at frequency locations within the audio signal.

6. The apparatus of claim 5, wherein the reduced bit representation and the key are used to determine magnitude of the digital watermark at the frequency locations.

7. The apparatus of claim 5, wherein the key is used to transform the digital watermark to obscure the digital watermark at the frequency locations within the audio signal.

8. The apparatus of claim 7, wherein the key is used to transform phase of the digital watermark within the audio signal.

9. The apparatus of claim 5, wherein digital watermark information is conveyed, at least in part, in the phase.

10. The apparatus of claim 9, wherein the phase is modulated with auxiliary data to convey auxiliary data in the audio signal.

11. The apparatus of claim 5, wherein the reduced bit representation comprises a sub-sampling of the audio signal.

12. The apparatus of claim 5, wherein the reduced bit representation is computed by filtering the audio signal into frequency components.

13. The apparatus of claim 5, wherein a plurality of keys are used to select the frequency location and magnitude of the digital watermark at the frequency locations.

14. The apparatus of claim 13, wherein the plurality of keys comprise a first key to select frequency location and a second key providing phase of the digital watermark.

15. The apparatus of claim 1, wherein the electronic processor is programmed for:

encoding at least first and second watermarks using corresponding keys, wherein the first watermark is encoded by inserting a signal with modulated frequency and the second watermark is encoded by inserting a signal with modulated phase.

16. An apparatus comprising:

electronic memory configured to store a media signal representing audio or video;

an electronic processor programmed for;

extracting a reduced-bit representation of the media signal;

influencing a digital watermark embedding process with the reduced-bit representation of the media signal by using the reduced-bit number to seed a pseudorandom number to generate a reference signal; and

embedding a digital watermark in the media signal, wherein the embedding embeds at least the reference signal in the media signal, wherein the reference signal provides information for correcting or compensating for geometric distortion.

17. An apparatus comprising:

electronic memory configured to store a media signal representing audio or video;

an electronic processor programmed for;

extracting data representing at least some features of the media signal;

using the extracted data as a key to select coefficients in a transform domain, wherein the coefficients represent the media signal; and

modifying selected coefficients to hide a steganographic signal in the media signal.

18. The apparatus of claim 17, wherein the key is further used to generate random phase information of a reference signal in the first transform domain, and wherein the electronic processor is programmed for embedding the reference signal in the media signal.

19. An apparatus comprising:

electronic memory configured to store a media signal comprising an auxiliary signal, the media signal comprising audio or video;

an electronic processor programmed for;

extracting data representing at least some features of the media signal;

influencing detection of the auxiliary signal with the data, wherein the data seeds a pseudorandom number generator, wherein a result of the pseudorandom number generator provides information used for detection; and

analyzing the media signal to detect the auxiliary signal with the information from the pseudorandom number generator.

20. The apparatus of claim 19, wherein the exacted data comprises media signal locations and values for the auxiliary signal.

21. The apparatus of claim 19, wherein the exacted data comprises coefficient magnitude values.

22. The apparatus of claim 19, wherein the information comprises phase data associated with the auxiliary signal.

23. An article of manufacture including a non-transitory computer-readable medium having instructions stored thereon that, if executed by a computing device, cause the computing device to perform operations comprising:

extracting a reduced-bit representation of the media signal;

adapting a digital watermark embedding process with the reduced-bit representation of the media signal; and

embedding a digital watermark in the media signal with the adapted digital watermark embedding process.

36. The method of claim 23, wherein the extracted data comprises a hash of the media signal.

24. An article of manufacture including a non-transitory computer-readable medium having instructions stored thereon that, if executed by a computing device, cause the computing device to perform operations comprising:

extracting data representing at least some features of the media signal;

influencing detection of the auxiliary signal with the data, wherein the data seeds a pseudorandom number generator, wherein a result of the pseudorandom number generator provides information used for detection; and

analyzing the media signal to detect the auxiliary signal with the information from the pseudorandom number generator.

25. A method comprising:

obtaining a media signal representing audio or video;

extracting data associated with some features of the media signal;

adapting a digital watermark embedding process with extracted data representing at least some features of the media signal, wherein the adapting comprises transforming a digital watermark at embedding locations according to an embedding key and at least some of the extracted data; and

embedding, using a processor, a digital watermark in the media signal with the adapted digital watermark embedding process.

26. The method of claim 25, wherein the media signal comprises an audio signal, and the embedding locations comprise time and frequency locations within the audio signal.

27. The method of claim 26, wherein the embedding key is derived at least in part from the extracted data and the method comprises mapping the digital watermark to the media signal at the embedding locations according to the embedding key.

28. The method of claim 26, wherein the extracted data is used to generate at least a portion of the embedding key.

29. The method of claim 28, wherein the extracted data seeds a pseudorandom generator utilized for adapting the digital watermark embedding process.

30. The method of claim 29, wherein the pseudorandom generator generates an embedding signal value.

31. The method of claim 29, wherein the pseudorandom generator generates an embedding location.

32. The method of claim 26, wherein the adapted digital watermark embedding process manipulates a plural-bit digital watermark payload carried by the digital watermark.

33. The method of claim 26, wherein the adapted digital watermark embedding process transforms a plural-bit digital watermark payload carried by the digital watermark.

34. The method of claim 25, wherein the extracted data comprises a filtered version of signal attributes.

35. The method of claim 25, wherein the extracted data comprises features at time-frequency locations of the media signal.

37. The method of claim 25, wherein the media signal comprise an audio signal and the extracted data comprises a sampling of the media signal at time locations within a frequency transform of the audio signal.

38. An apparatus comprising:

electronic memory for storing an audio signal comprising an auxiliary signal hidden therein;

an electronic processor programmed for;

extracting data associated with features of the audio signal;

influencing a digital watermark detection process with extracted data associated with features of the audio signal, wherein the influencing comprises adapting a decoding key for detecting a digital watermark from time-frequency locations in the audio signal from at least some of the extracted data, and

analyzing the audio signal at the time-frequency locations to detect the auxiliary signal with the influenced digital watermark detection process.

39. The apparatus of claim 38, wherein the extracted data comprises a key.

40. The apparatus of claim 39, wherein the key is associated with a specification of audio signal magnitudes.

41. The apparatus of claim 39, wherein the key specifies auxiliary signal encoding locations within the audio signal.

42. The method of claim 39, wherein the key seeds a pseudorandom generator utilized for influencing the digital watermark detection process.

43. The method of claim 39, wherein the pseudorandom generator generates auxiliary signal location values.

44. The method of claim 39, wherein the pseudorandom generator generates auxiliary signal phase information.

45. The method of claim 38, wherein the extracted data comprises locations and signal values of the auxiliary signal.

46. The method of claim 38, further comprising decoding the auxiliary signal once detected.

47. The method of claim 46, further comprising correcting the auxiliary signal once decoded.