Methods and apparatus for characterizing media

• US 8,364,491 B2
• Filed: 09/30/2011
• Issued: 01/29/2013
• Est. Priority Date: 02/20/2007
• 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, Ramaswamy, Arun
• Primary Examiner(s): He, Jialong
• Application Number:
  US13/250,663
• Publication Number:
  US 20120071995A1
• Time in Patent Office: 487 Days
• Field of Search: 704/273, 704/205, 725/18, 725/19, 713/179
• US Class Current: 704/273
• CPC Class Codes: H04H 20/14 for monitoring programmes
• 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 apparatus includes a transformer to convert at least a portion of a block of audio into a frequency domain representation including a plurality of frequency components; a decision metric processor to: define a band of frequency components having real and imaginary spectral components, define a plurality of frequency bins within the band, determine respective difference functions for each of the frequency bins using a product of the real and imaginary spectral components of a corresponding group of the frequency bins, the corresponding group for a first one of the frequency bins including at least the first one of the frequency bins and a second one of the frequency bins selected based on the first frequency bin, and determine a decision metric by summing the difference functions; and a signature determiner to determine a signature based on the decision metric.

Claims

1. An apparatus, comprising:

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

a decision metric processor to;

define a band of frequency components having real and imaginary spectral components;

define a plurality of frequency bins within the band;

determine respective functions for each of the frequency bins using a product of the real and imaginary spectral components of a corresponding group of the frequency bins, wherein the corresponding group for a first one of the frequency bins includes at least the first one of the frequency bins and a second one of the frequency bins selected based on the first frequency bin; and

determine a decision metric for the band by summing the functions;

a signature determiner to determine a signature based on a value of the decision metric; and

a processor to implement at least one of the transformer, the decision metric processor, or the signature determiner.

2. An apparatus as defined in claim 1, wherein determining the function for the first one of the frequency bins is based on the following equation:

3. An apparatus as defined in claim 1, further comprising a sample generator to capture the block of audio by digitally sampling an audio signal and storing the digital samples in a buffer.

4. An apparatus as defined in claim 3, wherein the sample generator is to capture a second block of audio by shifting a number of old samples from the buffer and shifting a number of new samples into the buffer.

5. An apparatus to create a signature representative of media, the apparatus comprising:

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

a decision metric processor to;

define a band of frequency components having real and imaginary spectral components;

define vectors for respective frequency components, the vector for a first one of the frequency components comprising the real and imaginary spectral components for the first one of the frequency components; and

determine a decision metric using linear combinations of dot products of the vectors for the frequency components; and

a signature determiner to determine the signature based on a value of the decision metric.

6. An apparatus as defined in claim 5, wherein determining the decision metric is based on the following equation:

7. An apparatus as defined in claim 6, wherein the signature is based on whether a value of the decision metric D_B is positive or negative.

8. A method, comprising:

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

defining a band of frequency components having real and imaginary spectral components;

defining a plurality of frequency bins within the band;

determining, using a processor, respective functions for each of the frequency bins using a product of the real and imaginary spectral components of a corresponding group of the frequency bins, wherein the corresponding group for a first one of the frequency bins includes at least the first one of the frequency bins and a second one of the frequency bins selected based on the first frequency bin;

determining, using the processor, a decision metric by summing the functions; and

determining a bit for a signature based on a value of the decision metric.

9. A method as defined in claim 8, wherein determining the function for the first one of the frequency bins is based on the following equation:

10. A method as defined in claim 8, wherein capturing the block of audio comprises digitally sampling an audio signal and storing the digital samples in a buffer.

11. A method as defined in claim 10, further comprising capturing a second block of audio by shifting a number of old samples from the buffer and shifting a number of new samples into the buffer.

12. A method as defined in claim 11, further comprising generating a second bit of the signature by:

converting at least a portion of the second block of audio into a second frequency domain representation including a second plurality of frequency components;

defining a second band of frequency components having real and imaginary spectral components;

defining a second plurality of frequency bins within the second band;

determining respective second functions for each of the second frequency bins using a product of the real and imaginary spectral components of a corresponding group of the second frequency bins, wherein the corresponding group for a first one of the second frequency bins includes at least the first one of the second frequency bins and a second one of the second frequency bins selected based on the first one of the second frequency bins;

determining a second decision metric by summing the second functions; and

determining the second bit for a signature based on a value of the decision metric.

13. A tangible article of manufacture comprising machine readable instructions which, when executed, cause a machine to at least:

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

define a band of frequency components having real and imaginary spectral components;

define a plurality of frequency bins within the band;

determine respective functions for each of the frequency bins using a product of the real and imaginary spectral components of a corresponding group of the frequency bins, wherein the corresponding group for a first one of the frequency bins includes at least the first one of the frequency bins and a second one of the frequency bins selected based on the first frequency bin;

determine a decision metric by summing the functions; and

determine a bit for a signature based on a value of the decision metric.

14. An article of manufacture as defined in claim 13, wherein determining the function for the first one of the frequency bins is based on the following equation:

15. An article of manufacture as defined in claim 13, wherein capturing the block of audio comprises digitally sampling an audio signal and storing the digital samples in a buffer.

16. An article of manufacture as defined in claim 15, further comprising capturing a second block of audio by shifting a number of old samples from the buffer and shifting a number of new samples into the buffer.

17. An article of manufacture as defined in claim 16, further comprising generating a second bit of the signature by:

converting at least a portion of the second block of audio into a second frequency domain representation including a second plurality of frequency components;

defining a second band of frequency components having real and imaginary spectral components;

defining a second plurality of frequency bins within the second band;

determining respective second functions for each of the second frequency bins using a product of the real and imaginary spectral components of a corresponding group of the second frequency bins, wherein the corresponding group for a first one of the second frequency bins includes at least the first one of the second frequency bins and a second one of the second frequency bins selected based on the first one of the second frequency bins;

determining a second decision metric by summing the second functions; and

determining the second bit for a signature based on a value of the decision metric.