METHODS AND APPARATUS FOR GENERATING SIGNAURES

• US 20090225994A1
• Filed: 11/06/2008
• Published: 09/10/2009
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Nielsen Company (US) LLC (RR Donnelley & Sons Company)
• Original Assignee: Nielsen Company (US) LLC (RR Donnelley & Sons Company)
• Inventors: Ramaswamy, Arun, Srinivasan, Venugopal, Topchy, Alexander Pavlovich
• Granted Patent: US 8,600,531 B2
• Time in Patent Office: Days
• US Class Current: 381/56
• CPC Class Codes: G06F 16/683 using metadata automatically derived from the content
• CPC Class Codes: G10L 25/48 specially adapted for particular use
• CPC Class Codes: G11B 27/28 by using information signals recorded by the same method as the main recording G11B27/22 takes precedence
• CPC Class Codes: H04H 2201/90 characterised by the use of signatures
• CPC Class Codes: H04H 60/37 for identifying segments of broadcast information, e.g. scenes or extracting programme ID
• CPC Class Codes: H04H 60/58 of audio determination or detection of speech characteristics in general G10L25/00; speech recognition in general G10L15/00
• CPC Class Codes: H04H 60/66 for using the result on distributors' side
• CPC Class Codes: H04N 21/442 Monitoring of processes or resources, e.g. detecting the failure of a recording device, monitoring the downstream bandwidth, the number of times a movie has been viewed, the storage space available from the internal hard disk arrangements for monitoring broadcast services or broadcast-related services H04H60/29; arrangements for identifying or recognising characteristics with a direct linkage to broadcast information H04H60/35; monitoring of user activities for profile generation for accessing a video database G06F16/739; monitoring in wireless networks H04W24/00
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

Signaturing methods and apparatus as described. In one example, a signaturing method includes capturing an audio signal, applying a first window function to a portion of the captured audio signal to produce a first windowed audio block, applying a second window function to the portion of the captured audio signal to produce a second windowed audio block, determining a first characteristic of a band of frequencies in the first windowed audio block, determining a second characteristic of the band of frequencies in the second windowed audio block, comparing the first characteristic to the second characteristic, and assigning a signature bit representative of the portion of the captured audio signal based on the comparison of the first characteristic and the second characteristic. Other examples are described.

Claims

1. A method of generating a signature representing a portion of an audio signal, the method comprising:

capturing an audio signal;

applying a first window function to a portion of the captured audio signal to produce a first windowed audio block;

applying a second window function to the portion of the captured audio signal to produce a second windowed audio block;

determining a first characteristic of a band of frequencies in the first windowed audio block;

determining a second characteristic of the band of frequencies in the second windowed audio block;

comparing the first characteristic to the second characteristic; and

assigning a signature bit representative of the portion of the captured audio signal based on the comparison of the first characteristic and the second characteristic.

2. A method as defined in claim 1, wherein applying the first window function to the portion of the captured audio signal to produce the first windowed audio block and applying the second window function to the portion of the captured audio signal to produce the second windowed audio block comprises frequency domain processing to create first and second transformed windowed audio blocks.

3. A method as defined in claim 2, wherein determining the first and second characteristics of the band of frequencies in the first and second windowed audio blocks comprises processing the first and second transformed windowed audio blocks.

4. A method as defined in claim 1, wherein capturing the audio signal comprises wireless audio capture.

5. A method as defined in claim 4, wherein capturing the audio signal comprises digital sampling.

6. A method as defined in claim 1, wherein the first and second window functions comprise complimentary functions.

7. A method as defined in claim 6, wherein the first window function comprises a large magnitude at upper and lower ends of the first window function.

8. A method as defined in claim 7, wherein the second window function comprises a small magnitude at upper and lower ends of the second window function.

9. A method as defined in claim 6, wherein the first window function comprises a large magnitude at an upper end of the first window function and a small magnitude at a lower end of the first window function.

10. A method as defined in claim 9, wherein the second window function comprises a small magnitude at an upper end of the second window function and a large magnitude of a lower end of the second window function.

11. A method as defined in claim 1, wherein the first window function and the second window function are selected from a set of window functions.

12. A method as defined in claim 11, wherein the first window function and the second window function are arbitrarily selected from the set of window functions.

13. A method as defined in claim 1, wherein applying the first window function to the portion of the captured audio signal comprises multiplying the first window function and the portion of the captured audio signal in a time domain operation.

14. A method as defined in claim 13, wherein applying the second window function to the portion of the captured audio signal comprises multiplying the second window function and the portion of the captured audio signal in a time domain operation.

15. A method as defined in claim 1, wherein the first and second characteristics comprise first and second energies.

16. A method as defined in claim 15, wherein comparing the first and second characteristic comprises subtracting first and second energies.

17. A method as defined in claim 16, wherein assigning a signature bit comprises assigning a signature bit value based on a result of the subtraction of the first and second energies.

18. A method as defined in claim 15, further comprising determining additional characteristics in each of the first and second windowed audio blocks and using the additional characteristics to determine additional bits representative of the portion of the captured audio signal.

19. A method as defined in claim 1, further comprising:

applying a third window function and a fourth window function to the portion of the captured audio to produce a third windowed audio block and a fourth windowed audio block; and

processing the third windowed audio block and the fourth windowed audio block to determine additional bits representative of a the portion of the captured audio signal.

20. A method as defined in claim 19, wherein the processing includes comparing one or more of a third characteristic of the third windowed audio block, a fourth characteristic of the fourth windowed audio block, the first characteristic, or the second characteristic.

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

capture an audio signal;

apply a first window function to a portion of the captured audio signal to produce a first windowed audio block;

apply a second window function to the portion of the captured audio signal to produce a second windowed audio block;

determine a first characteristic of a band of frequencies in the first windowed audio block;

determine a second characteristic of the band of frequencies in the second windowed audio block;

compare the first characteristic to the second characteristic; and

assign a signature bit representative of the portion of the captured audio signal based on the comparison of the first characteristic and the second characteristic.

22. A computer readable medium as defined by claim 21, wherein applying the first window function to the portion of the captured audio signal to produce the first windowed audio block and applying the second window function to the portion of the captured audio signal to produce the second windowed audio block comprises frequency domain processing to create first and second transformed windowed audio blocks.

23. A computer readable medium as defined by claim 22, wherein determining the first and second characteristics of the band of frequencies in the first and second windowed audio blocks comprises processing the first and second transformed windowed audio blocks.

24-30. -30. (canceled)

31. An apparatus to generate a signature representing a portion of an audio signal, the apparatus comprising:

a sample generator to capture an audio signal;

a windower to apply a first window function to a portion of the captured audio signal to produce a first windowed audio block and to apply a second window function to the portion of the captured audio signal to produce a second windowed audio block;

a characteristic determiner to determine a first characteristic of a band of frequencies in the first windowed audio block and to determine a second characteristic of the band of frequencies in the second windowed audio block;

a comparator to compare the first characteristic to the second characteristic; and

a signature determiner to assign a signature bit representative of the portion of the captured audio signal based on the comparison of the first characteristic and the second characteristic.

32. An apparatus as defined in claim 31, wherein the windower applies the first window function to the portion of the captured audio signal to produce the first windowed audio block and applies the second window function to the portion of the captured audio signal to produce the second windowed audio block using frequency domain processing to create first and second transformed windowed audio blocks.

33. An apparatus as defined in claim 32, wherein the characteristic determiner determines the first and second characteristics of the band of frequencies in the first and second windowed audio blocks comprises by processing the first and second transformed windowed audio blocks.

34. An apparatus as defined in claim 31, wherein the first and second window functions comprise complimentary functions.

35. An apparatus as defined in claim 34, wherein the windower applies the first window function to the portion of the captured audio signal by multiplying the first window function and the portion of the captured audio signal in a time domain operation.

36. An apparatus as defined in claim 35, wherein the windower applies the second window function to the portion of the captured audio signal by multiplying the second window function and the portion of the captured audio signal in a time domain operation.

37. An apparatus as defined in claim 31, wherein the first and second characteristics comprise first and second energies.

38-40. -40. (canceled)