Methods and apparatus to generate threshold values for state detection

1. An apparatus, comprising:

a collection of audio data elements each representative of a sound level present in an environment at a time of an ON-indication, an oldest one of the audio data elements to be replaced in response to detection of an ON-indication in the environment; and

a selector, implemented via a logic circuit, to select, for a value of a threshold condition of a state detection analysis, one of the audio data elements corresponding to a quietest sound level.

2. An apparatus as defined in claim 1 , further comprising acounter to:

increment a count when an ON-indication is detected in the environment; and

trigger replacement of the oldest one of the audio data elements in response to the count reaching a particular number.

3. An apparatus as defined in claim 1 , the audio data elements representing respective audio gain levels, the selector to select the one of the audio data elements corresponding to the quietest sound level by selecting a greatest one of audio gain levels.

4. An apparatus as defined in claim 1 , further comprising an adjustor to weight the value selected for the threshold condition according to a fixed weighting ratio.

5. An apparatus as defined in claim 1 , further comprising an audio data obtainer to populate the collection with the audio data elements, the audio data obtainer to obtain audio information corresponding to the audio data element is in response to the detection of the ON-indication.

6. An apparatus as defined in claim 1 , the detection of the ON-indication comprising detection of media identifying information in the environment.

7. An apparatus as defined in claim 1 , the audio data elements including audio gain levels associated with automatic gain control functionality.

8. A method, comprising:

in response to an ON-indication being detected in an environment including a media presentation device, updating a collection of audio data elements with an audio data element corresponding to a time of the detection of the ON-indication;

identifying which one of the audio data elements of the collection corresponds to a quietest sound level; and

selecting the identified one of the audio elements as a current value of a threshold condition used in a state detection analysis of the media presentation device.

9. A method as defined in claim 8 , wherein updating the collection of audio data elements comprises discarding an oldest one of the audio data elements and adding the audio data element corresponding to the time of the detection of the ON-indication.

10. A method as defined in claim 8 , further comprising, in response to the ON-indication being detected, incrementing a count and determining whether the count has reached a trigger value.

11. A method as defined in claim 10 , further comprising, when the count has reached the trigger value, triggering the identifying of which one of the audio elements of the collection corresponds to the quietest sound level.

12. A method as defined in claim 8 , further comprising adjusting the identified one of the audio elements according to a weighting ratio or an offset.

13. A method as defined in claim 8 , wherein the audio data elements of the collection are audio gain levels, and the identifying of which one of the audio data elements of the collection corresponds to the quietest sound level comprises identifying a greatest one of the audio gain levels.

14. A method as defined in claim 13 , wherein the audio gain levels are obtained from an automatic gain control component utilized by a media detector.

15. A method as defined in claim 8 , further comprising providing the identified one of the audio data element to a comparator used in the state detection analysis.

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

in response to an ON-indication being detected in an environment including a media presentation device, update a collection of audio data elements with an audio data element corresponding to a time of the detection of the ON-indication;

identify which one of the audio data elements of the collection corresponds to a quietest sound level; and

select the identified one of the audio elements as a current value of a threshold condition used in a state detection analysis of the media presentation device.

17. A storage medium as defined in claim 16 , wherein the instructions, when executed, cause the machine device to update the collection of audio data elements by discarding an oldest one of the audio data elements and adding the audio data element corresponding to the time of the detection of the ON-indication.

18. A storage medium as defined in claim 16 , wherein the instructions, when executed, cause the machine device to, in response to the ON-indication being detected, increment a count and determining whether the count has reached a trigger value.

19. A storage medium as defined in claim 18 , wherein the instructions, when executed, cause the machine to, when the count has reached the trigger value, trigger the identifying of which one of the audio elements of the collection corresponds to the quietest sound level.

20. A storage medium as defined in claim 16 , wherein the instructions, when executed, cause the machine to adjust the identified one of the audio elements according to a weighting ratio or an offset.

21. A storage medium as defined in claim 16 , wherein the audio data elements of the collection are audio gain levels, and the instructions, when executed, cause the machine to identify of which one of the audio data elements of the collection corresponds to the quietest sound level by identifying a greatest one of the audio gain levels.

22. A storage medium as defined in claim 16 , wherein the instructions, when executed cause the machine to provide the identified one of the audio data element to a comparator used in the state detection analysis.