Methods and apparatus for generating signatures

• US 9,136,965 B2
• Filed: 05/31/2013
• Issued: 09/15/2015
• Est. Priority Date: 05/02/2007
• Status: Active Grant

• Current Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Original Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Inventors: Topchy, Alexander, Srinivasan, Venugopal
• Primary Examiner(s): ROBERTS, SHAUN A
• Application Number:
  US13/907,278
• Publication Number:
  US 20130261781A1
• Time in Patent Office: 837 Days
• Field of Search: 704/205, 704/273, 725/9, 725 18- 19, 725/22, 700/94, 713/176
• US Class Current: 1/1
• CPC Class Codes: G06F 16/683 using metadata automatically derived from the content
• CPC Class Codes: H04H 20/14 for monitoring programmes
• CPC Class Codes: H04H 2201/90 characterised by the use of signatures
• CPC Class Codes: H04H 60/58 of audio determination or detection of speech characteristics in general G10L25/00; speech recognition in general G10L15/00

Abstract

Methods and apparatus for characterizing media are described. An example method includes converting at least a portion of a block of audio into a frequency domain representation, dividing the frequency domain representation into bands, determining a characteristic difference of a first band of the bands, and determining a signature bit based on the characteristic difference, wherein determining the signature bit is performed differently based on whether an index of the first band has a first property.

Claims

1. A method of characterizing media comprising:

converting at least a portion of a block of audio into a frequency domain representation;

dividing the frequency domain representation into bands;

determining, using the processor, a characteristic difference of a first band of the bands; and

determining, using the processor, a signature bit based on the characteristic difference, wherein determining the signature bit is performed differently based on whether an index of the first band has a first property.

2. A method as defined in claim 1, wherein determining the signature bit comprises:

when the index has the first property, determining the signature bit based on comparing the characteristic difference to a first value based on a second characteristic difference of a second band of the bands; and

when the index does not have the first property, determining the signature bit based on comparing the characteristic difference to a second value based on a third characteristic difference of a third band of the bands.

3. A method as defined in claim 2, wherein determining the signature bit further comprises comparing the characteristic difference to a threshold.

4. A method as defined in claim 1, wherein dividing the frequency domain representation into the bands comprises grouping frequency components that are adjacent in the frequency domain representation.

5. A method as defined in claim 4, wherein the frequency components have frequencies in an audible frequency range.

6. A method as defined in claim 1, wherein determining the characteristic of a selected band comprises determining an energy in the selected band.

7. An apparatus comprising:

a transformer to convert at least a portion of a block of audio into a frequency domain representation;

a divider to divide the frequency domain representation into bands;

a characteristic determiner to determine a first characteristic of a first band of the bands and to determine a second characteristic of a second band of the bands;

a subtractor to determine a characteristic difference between the first characteristic and the second characteristic; and

a signature determiner to determine a signature bit based on the characteristic difference, the signature determiner to determine the signature bit differently based on whether an index of the first band has a first property.

8. An apparatus as defined in claim 7, wherein the signature determiner is to:

when the index has the first property, determine the signature bit by comparing the characteristic difference to a first value, the first value based on a second characteristic difference of a second band of the bands; and

when the index does not have the first property, determine the signature bit by comparing the characteristic difference to a second value, the second value based on a third characteristic difference of a third band of the bands.

9. An apparatus as defined in claim 8, wherein the signature determiner is to determine the signature bit by comparing the characteristic difference to a threshold.

10. An apparatus as defined in claim 7, wherein the characteristic of the first band occurs at a time that is different than a time at which the characteristic of the second band takes place.

11. An apparatus as defined in claim 7, wherein the characteristic determiner is to determine the first characteristic by determining an energy in the first band.

12. An apparatus as defined in claim 7, wherein the characteristic of the first band occurs later in time than the characteristic of the second band.

13. A tangible machine readable storage device medium comprising instructions that, when executed, cause a machine to at least:

convert at least a portion of a block of audio into a frequency domain representation;

divide the frequency domain representation into bands;

determine a characteristic difference of a first band of the bands; and

determine a signature bit based on the characteristic difference, wherein the instructions cause the machine to determine the signature bit differently based on whether an index of the first band has a first property.

14. A machine readable storage device as defined in claim 13, wherein the instructions are to cause the machine to determine the signature bit by:

when the index has the first property, comparing the characteristic difference to a first value, the first value based on a second characteristic difference of a second band of the bands; and

when the index does not have the first property, comparing the characteristic difference to a second value, the second value based on a third characteristic difference of a third band of the bands.

15. A machine readable storage device as defined in claim 14, wherein the instructions are to cause the machine to determine the signature bit by comparing the characteristic difference to a threshold.

16. A machine readable storage device as defined in claim 13, wherein the instructions are to cause the machine to divide the frequency domain representation into the bands by grouping frequency components that are adjacent in the frequency domain representation.