Methods and apparatus for determining whether a media presentation device is in an on state or an off state

1. A method for determining whether a media presentation device is in an on state or an off state, the method comprising:

determining first and second characteristics of a signature associated with a signal representative of media content presented via the media presentation device;

evaluating the first and second characteristics to determine first and second fuzzy contribution values, the first fuzzy contribution value representing a degree with which the first characteristic corresponds to the media presentation device being in at least one of the on state or the off state, the second fuzzy contribution value representing a degree with which the second characteristic corresponds to the media presentation device being in at least one of the on state or the off state;

determining an audio test score based on a number of the first and second contribution values that indicate the media presentation device is in one of the on state or the off state;

converting the audio test score into a third fuzzy contribution value;

combining the first, second and third fuzzy contribution values to calculate an intermediate fuzzy score; and

determining whether the media presentation device is in the on state or the off state based on the intermediate fuzzy score.

2. A method as defined in claim 1 , wherein the signal comprises an audio signal associated with the media content, the audio signal being collected by an audience measurement device.

3. A method as defined in claim 1 , further comprising: calculating a fourth fuzzy contribution value based on a gain applied to a microphone of an audience measurement device that detected the signal representative of the media content; wherein combining the first, second and third fuzzy contribution values to calculate the intermediate fuzzy score further comprises combining the first, second, third and fourth fuzzy contribution values to calculate the intermediate fuzzy score.

4. A method as defined in claim 3 wherein the fourth fuzzy contribution is calculated by subtracting the gain from a first constant to form a first difference and multiplying the first difference by a second constant.

5. A method as defined in claim 1 , wherein determining the first characteristic of the signature further comprises integrating a magnitude associated with the signature over a period of time.

6. A method as defined in claim 1 , wherein determining the second characteristic of the signature further comprises determining a standard deviation of a magnitude associated with the signature over a period of time.

7. A method as defined in claim 1 , further comprising calculating a fifth fuzzy contribution value based on a hint from a remote control device associated with the media presentation device, wherein combining the first, second and third fuzzy contribution values to calculate the intermediate fuzzy score further comprises combining the first, second, third and fifth fuzzy contribution values to calculate the intermediate fuzzy score.

8. A method as defined in claim 1 , wherein the intermediate fuzzy score comprises a first intermediate fuzzy score, and further comprising averaging the first intermediate fuzzy score with a second intermediate fuzzy score to calculate a first final fuzzy score for a time period associated with the first and second intermediate fuzzy scores.

9. A method as defined in claim 8 , further comprising at least one of normalizing or filtering the first final fuzzy score.

10. A method as defined in claim 8 , further comprising adjusting the first final fuzzy score by a first amount if the signature matched a reference signature in a database and adjusting the first final fuzzy score by a second amount if the signature did not match a reference signature in the database.

11. A method as defined in claim 10 , wherein the first amount and the second amount have different polarities.

12. A method as defined in claim 8 , wherein determining whether the media presentation device is in the on state or the off state based on the intermediate fuzzy score comprises determining whether the media presentation device is in the on state or the off state based on the first final fuzzy score.

13. An apparatus for determining whether a media presentation device is in an on state or an off state, the apparatus comprising:

a signal characteristic determiner to determine first and second characteristics of a signature associated with a signal representative of media content presented via the media presentation device;

a first evaluator to evaluate the first characteristic to determine a first fuzzy contribution value, the first fuzzy contribution value representing a degree to which the first characteristic corresponds to the media presentation device being in at least one of the on state or the off state;

a second evaluator to evaluate the second characteristic to determine a second fuzzy contribution value, the second fuzzy contribution value representing a degree to which the second characteristic corresponds to the media presentation device being in at least one of the on state or the off state;

an input convergence evaluator to determine an audio test score based on a number of the first and second contribution values that indicate the media presentation device is in one of the on state or the off state, and to convert the audio test score into a third fuzzy contribution value;

a fuzzy contribution analyzer to combine the first, second and third fuzzy contribution values to calculate an intermediate fuzzy score; and

a creditor to determine whether the media presentation device is in the on state or the off state based on the intermediate fuzzy score.

14. An apparatus as defined in claim 13 , wherein the signal representative of the media content is an audio signal associated with the media content, the audio signal being collected by an audience measurement device.

15. An apparatus as defined in claim 13 , wherein the third fuzzy contribution is set to a first constant when none of the first and second fuzzy contributions indicate that the media presentation device is in the on state, the third fuzzy contribution is set to a second constant when one of the first and second fuzzy contributions indicate that the media presentation device is in the on state, and the third fuzzy contribution is set to a third constant when both of the first and second fuzzy contributions indicate that the media presentation device is in the on state.

16. An apparatus as defined in claim 13 , further comprising a gain evaluator to calculate a fourth fuzzy contribution value based on a gain applied to a microphone of an audience measurement device that detected the signal representative of the media content; wherein the fuzzy contribution analyzer is to combine the first, second, third and fourth fuzzy contribution values to calculate the intermediate fuzzy score.

17. An apparatus as defined in claim 16 , wherein the fourth fuzzy contribution is calculated by subtracting the gain from a first constant to form a first difference and multiplying the first difference by a second constant.

18. An apparatus as defined in claim 13 , wherein the first evaluator determines the first fuzzy contribution value by integrating a magnitude associated with the signature over a period of time.

19. An apparatus as defined in claim 18 , wherein the first evaluator determines the first fuzzy contribution by subtracting a first constant from the integrated magnitude to form a difference.

20. An apparatus as defined in claim 19 , wherein, if the difference has a negative polarity, the first evaluator multiplies the difference with a second constant.

21. An apparatus as defined in claim 13 , wherein the second evaluator determines the second fuzzy contribution value by determining a standard deviation of a magnitude associated with the signature over a period of time.

22. An apparatus as defined in claim 21 , wherein the second evaluator subtracts a constant from the standard deviation of the magnitude.

23. An apparatus as defined in claim 13 , further comprising a remote control hint evaluator to calculate a fifth fuzzy contribution value based on a hint from a remote control device associated with the media presentation device, wherein the fuzzy contribution analyzer is to combine the first, second, third and fifth fuzzy contribution values to calculate the intermediate fuzzy score.

24. An apparatus as defined in claim 13 , wherein the intermediate fuzzy score comprises a first intermediate fuzzy score, and wherein the fuzzy contribution analyzer averages the first intermediate fuzzy score with a second intermediate fuzzy score to calculate a first final fuzzy score for a time period associated with the first and second intermediate fuzzy scores.

25. An apparatus as defined in claim 24 , wherein the fuzzy contribution analyzer is to at least one of normalize or filter the first final fuzzy score.

26. An apparatus as defined in claim 24 , further comprising a crediting contribution analyzer to adjust the first final fuzzy score by a first amount if the signature matched a reference signature in a database and to adjust the first final fuzzy score by a second amount if the signature did not match a reference signature in the database.

27. An apparatus as defined in claim 26 , wherein the first amount and the second amount have different polarities.

28. An apparatus as defined in claim 13 , wherein the creditor determines whether the media presentation device is in the on state or the off state based on the first final fuzzy score.

29. A machine readable medium storing machine readable instructions that, when executed, cause a machine to:

determine first and second characteristics of a signature associated with a signal representative of media content presented via a media presentation device;

evaluate the first and second characteristics to determine first and second fuzzy contribution values, the first fuzzy contribution value representing a degree with which the first characteristic corresponds to the media presentation device being in at least one of an on state or an off state, the second fuzzy contribution value representing a degree with which the second characteristic corresponds to the media presentation device being in at least one of the on state or the off state;

determine an audio test score based on a number of the first and second contribution values that indicate the media presentation device is in one of the on state or the off state;

convert the audio test score into a third fuzzy contribution value;

combine the first, second and third fuzzy contribution values to calculate an intermediate fuzzy score; and

determine whether the media presentation device is in the on state or the off state based on the intermediate fuzzy score.