Methods and systems for reducing spillover by detecting signal distortion

1. A method to credit media presented by a media presentation device, the method comprising:

determining, via a processor, an actual frequency spectrum of the media monitored by a meter;

determining, via the processor, absolute values of differences between amplitudes of corresponding frequency components of the actual frequency spectrum and an expected frequency spectrum, the expected frequency spectrum stored in a database in association with a media identifier corresponding to the media;

determining, via the processor, whether spillover occurred based on a summation of the absolute values satisfying a threshold; and

crediting, via the processor, the media with a media exposure if spillover did not occur.

2. The method as defined in claim 1 , wherein the meter is a portable people meter to be worn or carried by a panelist.

3. The method as defined in claim 1 , wherein the actual frequency spectrum is based on a sample of the media presented by the media presentation device and collected by the meter.

4. The method as defined in claim 3 , further including discarding, via the processor, the sample of the media corresponding to the actual frequency spectrum if spillover did occur.

5. The method as defined in claim 3 , further including;

determining, via the processor, whether the actual frequency spectrum represents a sound not associated with the media; and

when the actual frequency spectrum represents the sound not associated with the media, discarding, via the processor, the sample of the media corresponding to the actual frequency spectrum before determining the absolute values of the differences between the amplitudes of the corresponding frequency components of the actual frequency spectrum and the expected frequency spectrum.

6. The method as defined in claim 1 , wherein the expected frequency spectrum is calculated prior to determining the actual frequency spectrum of the media.

7. The method as defined in claim 1 , wherein the determining that spillover occurred indicates that the meter is in a different room from the media presentation device.

8. An apparatus to credit media presented by a media presentation device, the apparatus comprising:

a frequency spectrum analyzer to determine an actual frequency spectrum of the media monitored by a meter;

a frequency spectrum comparator to:

determine absolute values of differences between amplitudes of corresponding frequency components of the actual frequency spectrum and an expected frequency spectrum, the expected frequency spectrum stored in a database in association with a media identifier corresponding to the media;

determine whether spillover occurred based on a summation of the absolute values satisfying a threshold; and

a media creditor to:

credit the media with a media exposure if spillover did not occur; and

not credit the media with the media exposure if spillover did occur.

9. The apparatus as defined in claim 8 , wherein the meter is a portable people meter to be worn or carried by a panelist.

10. The apparatus as defined in claim 8 , wherein the actual frequency spectrum is based on a sample of the media presented by the media presentation device and collected by the meter.

11. The apparatus as defined in claim 10 , wherein the media creditor is further to discard the sample of the media corresponding to the actual frequency spectrum if spillover did occur.

12. The apparatus as defined in claim 10 , wherein the frequency spectrum analyzer is further to:

determine whether the actual frequency spectrum represents a sound not associated with the media; and

when the actual frequency spectrum represents the sound not associated with the media, discard the sample of the media corresponding to the actual frequency.

13. The apparatus as defined in claim 8 , wherein the expected frequency spectrum is calculated prior to determining the actual frequency spectrum of the media.

14. The apparatus as defined in claim 8 , wherein determining that spillover occurred indicates that the meter is in a different room from the media presentation device.

15. A tangible computer readable storage medium comprising instructions that, when executed, cause a computing device to:

determine an actual frequency spectrum of the media monitored by a meter;

determine absolute values of differences between amplitudes of corresponding frequency components of the actual frequency spectrum and an expected frequency spectrum, the expected frequency spectrum stored in a database in association with a media identifier corresponding to the media;

determine whether spillover occurred based on a summation of the absolute values satisfying a threshold; and

credit the media with a media exposure if spillover did not occur.

16. The tangible computer readable storage medium as defined in claim 15 , wherein the meter is a portable people meter to be worn or carried by a panelist.

17. The tangible computer readable storage medium as defined in claim 15 , wherein the actual frequency spectrum is based on a sample of the media presented by the media presentation device and collected by the meter.

18. The tangible computer readable storage medium as defined in claim 17 , further including instructions that, when executed, cause the computing device to discard the sample of the media corresponding to the actual frequency spectrum if spillover did occur.

19. The tangible computer readable storage medium as defined in claim 15 , wherein the expected frequency spectrum is calculated prior to determining the actual frequency spectrum of the media.

20. The tangible computer readable storage medium as defined in claim 15 , wherein determining that spillover occurred indicates that the meter is in a different room from the media presentation device.