Methods and apparatus to detect spillover in an audience monitoring system

• US 9,912,990 B2
• Filed: 10/21/2016
• Issued: 03/06/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Original Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Inventors: Lee, Morris
• Primary Examiner(s): TRAN, THANG V
• Application Number:
  US15/299,898
• Publication Number:
  US 20170041667A1
• Time in Patent Office: 501 Days
• CPC Class Codes: G01S 3/808 using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 3/8083 determining direction of source
• CPC Class Codes: H04N 21/25891 being end-user preferences retrieval of video data in a video database based on user preferences G06F16/739; arrangements for recognizing users' preferences H04H60/46; user profiles in network data switching protocols H04L67/306; processing of user preferences or user profiles in wireless networks H04W8/18
• CPC Class Codes: H04N 21/42203 sound input device, e.g. microphone
• CPC Class Codes: H04N 21/4394 involving operations for analysing the audio stream, e.g. detecting features or characteristics in audio streams arrangements characterised by components specially adapted for monitoring, identification or recognition of audio in broadcast systems H04H60/58
• CPC Class Codes: H04N 21/44204 Monitoring of content usage, e.g. the number of times a movie has been viewed, copied or the amount which has been watched monitoring of user activities for profile generation for accessing a video database G06F16/739; protecting generic digital content where the protection is independent of the precise nature of the content G06F21/10; arrangements for monitoring the use made of the broadcast services in broadcast systems H04H60/31
• CPC Class Codes: H04N 21/44213 Monitoring of end-user related data arrangements for monitoring the users' behaviour or opinions in broadcast systems H04H60/33
• CPC Class Codes: H04N 21/8352 involving content or source identification data, e.g. Unique Material Identifier [UMID]
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Methods and apparatus to detect spillover in an audience monitoring system are disclosed. An example method includes sampling a first audio signal received by a first microphone. A second audio signal received by a second microphone is sampled. The second microphone is separated from the first microphone by a first distance. A time delay between receipt of the first and second sampled audio signals is calculated. Whether the time delay is within a threshold time difference is determined. When the time delay is within the threshold time difference, the media is identified as local media. When the time delay exceeds the threshold time difference, the media is identified as spillover media.

Claims

1. A method to distinguish local media from spillover media, the method comprising:

sampling a first audio signal associated with media received by a first microphone;

sampling a second audio signal associated with the media received by a second microphone, the second microphone being separated from the first microphone by a first distance;

calculating, with a processor, a time delay between receipt of the first and second sampled audio signals;

determining, with the processor, whether the time delay is within a threshold time difference;

when the time delay is within the threshold time difference, identifying the media as local media; and

when the time delay exceeds the threshold time difference, identifying the media as spillover media.

2. The method as defined in claim 1, further including:

calculating an absolute value of the first audio signal and the second audio signal; and

applying a first and second threshold to the first and second audio signals, respectively.

3. The method as defined in claim 2, further including:

removing samples from the first audio signal with intensities below the first threshold; and

removing samples from the second audio signal with intensities below the second threshold.

4. The method as defined in claim 3, wherein the first and second thresholds are determined such that removing samples from the first and second audio signals removes a majority of the samples from the first and second audio signals.

5. The method as defined in claim 1, further including:

calculating a moving average of the first and second audio signals;

selecting a first set of samples from the first audio signal;

selecting a second set of samples from the second audio signal; and

determining a first correlation value between the first set of samples and the second set of samples.

6. The method as defined in claim 5, wherein each point of the moving average of the first and second audio signals includes an average of two samples from the first and second audio signals, respectively.

7. The method as defined in claim 6, wherein the first set of samples includes samples from the first audio signal that are equally spaced between a first point in time and a second point in time.

8. The method as defined in claim 7, wherein the second set of samples includes samples from the second audio signal that are equally spaced between the first point in time and the second point in time.

9. The method as defined in claim 8, further including:

selecting a third set of samples from the second audio signal, the third set of samples being offset from the second set of samples by a first number of samples; and

determining a second correlation value between the first set of samples and the third set of samples, the time delay being determined using a greater of the first correlation value and the second correlation value.

10. A tangible machine-readable storage medium comprising instructions which, when executed, cause a processor to at least:

sample a first audio signal associated with media received by a first microphone;

sample a second audio signal associated with the media received by a second microphone, the second microphone being separated from the first microphone by a first distance;

calculate a time delay between receipt of the first and second sampled audio signals;

determine whether the time delay is within a threshold time difference;

when the time delay is within the threshold time difference, retain the media as local media; and

when the time delay exceeds the threshold time difference, ignore the media as spillover media.

11. The tangible machine-readable storage medium as defined in claim 10, wherein the instructions, when executed, cause the processor to at least:

calculate an absolute value of the first audio signal and the second audio signal; and

apply a first and second threshold to the first and second audio signals, respectively.

12. The tangible machine-readable storage medium as defined in claim 11, wherein the instructions, when executed, cause the processor to at least:

removing samples from the first audio signal with intensities below the first threshold; and

removing samples from the second audio signal with intensities below the second threshold.

13. The tangible machine-readable storage medium as defined in claim 10, wherein the instructions, when executed, cause the processor to at least:

calculate a moving average of the first and second audio signals;

select a first set of samples from the first audio signal;

select a second set of samples from the second audio signal; and

determine a first correlation value between the first set of samples and the second set of samples.

14. The tangible machine-readable storage medium as defined in claim 13, wherein each point of the moving average of the first and second audio signals includes an average of two samples from the first and second audio signals, respectively.

15. The tangible machine-readable storage medium as defined in claim 14, wherein the first set of samples includes samples from the first audio signal that are equally spaced between a first point in time and a second point in time.

16. The tangible machine-readable storage medium as defined in claim 15, wherein the second set of samples includes samples from the second audio signal that are equally spaced between the first point in time and the second point in time.

17. The tangible machine-readable storage medium as defined in claim 16, wherein the instructions, when executed, cause the processor to at least:

select a third set of samples from the second audio signal, the third set of samples being offset from the second set of samples by a first number of samples; and

determine a second correlation value between the first set of samples and the third set of samples, the time delay being determined using a greater of the first correlation value and the second correlation value.

18. An apparatus to distinguish local media from spillover media comprising:

an audio sampler to sample a first audio signal associated with media received by a first microphone and sample a second audio signal associated with the media received by a second microphone, the second microphone being separated from the first microphone by a first distance;

a direction detector to determine a time difference between receipt of the first and second sampled audio signals; and

a filter to determine whether the time difference is within a threshold time difference, the filter to retain the media as local media when the time difference is within the threshold time difference, the filter to ignore the media as spillover media when the time difference exceeds the threshold time difference, at least one of the audio sampler, the direction detector, or the filter being implemented by hardware.

19. The apparatus as defined in claim 18, wherein a source of the audio is a media device.

20. The apparatus as defined in claim 18, further including:

an absolute value calculator to calculate a first absolute value of the first sampled audio signal, the absolute value calculator to calculate a second absolute value of the second sampled audio signal; and

a threshold processor to apply a first and second threshold to the first and second absolute value audio signals, respectively.