Methods and apparatus for analyzing microphone placement for watermark and signature recovery
View Patent ↗Methods and apparatus to analyze microphone placement for watermarks and signatures are disclosed. An example apparatus includes a signal transformer to determine a frequency spectrum of a received noise burst; a variance determiner to compute a variance of a frequency band in the frequency spectrum; and a detection rates determiner to determine a recovery rate of at least one of a watermark or a signature based on the computed variance.
1. An apparatus to analyze microphone placement for watermark extraction and signature generation, the apparatus comprising:
a signal transformer to determine a frequency spectrum of a noise burst received with a microphone, the noise burst converted to a digital signal with a meter communicatively coupled to the microphone and the signal transformer;
a variance determiner to compute a variance of a magnitude spectrum of at least one of a first frequency band associated with first media or a second frequency band associated with second media, the first and second frequency bands corresponding to the digital signal representative of the frequency spectrum; and
a detection rates determiner to:
determine, based on the computed variance and at least one of a first mapping for the first frequency band or a second mapping for the second frequency band, a recovery rate associated with at least one of watermark detection or signature generation performed on an audio signal of at least one of the first or second frequency band corresponding to the first and second media, respectively, received with the microphone, the recovery rate corresponding to a placement of the microphone; and
output the recovery rate to a user interface.
2. The apparatus of claim 1 , wherein the detection rates determiner is to map the computed variance to a detection value representative of a percentage of detections of at least one of the watermark or the signature corresponding to at least one of the first frequency band or the second frequency band.
3. The apparatus of claim 2 , wherein the detection rates determiner is to determine the recovery rate based on at least one of the first or second mapping.
4. The apparatus of claim 1 , further including the user interface to display a location status based on the recovery rate.
5. The apparatus of claim 1 , wherein the microphone is associated with the meter.
6. The apparatus of claim 5 , further including a meter interface to couple to the meter, the meter interface to, when connected to the meter, receive the noise burst from the meter.
7. The apparatus of claim 1 , wherein the noise burst is output by at least one of a media output device or speaker corresponding to the media output device.
8. The apparatus of claim 7 , further including an interface to transmit instructions to the at least one of the media output device or the speaker to output the noise burst.
9. A method to analyze microphone placement for watermark extraction and signature generation, the method comprising:
determining, by executing an instruction with a processor, a frequency spectrum of a noise burst received with a microphone, the noise burst converted to a digital signal with a meter communicatively coupled to the microphone;
computing, by executing an instruction with the processor, a variance of a magnitude spectrum of at least one of a first frequency band associated with first media or a second frequency band associated with second media, the first and second frequency bands corresponding to the digital signal representative of the frequency spectrum;
determining, by executing an instruction with the processor and based on the computed variance and at least one of a first mapping for the first frequency band or a second mapping for the second frequency band, a recovery rate associated with at least one of watermark detection or signature generation performed on an audio signal of at least one of the first or second frequency band corresponding to the first and second media, respectively, received with the microphone the recovery rate corresponding to a location of the microphone; and
outputting a status of the location of the microphone to a user interface, the status of the location corresponding to the recovery rate.
10. The method of claim 9 , further including mapping the computed variance to a detection value corresponding to a percentage of detections of at least one of the watermark or the signature corresponding to at least one of the first frequency band or the second frequency band.
11. The method of claim 10 , further including determining the recovery rate based on at least one of the first or second mapping.
12. The method of claim 9 , wherein the microphone is associated with the meter.
13. The method of claim 9 , wherein the noise burst is output by at least one of a media output device or a speaker corresponding to the media output device.
14. The method of claim 9 , further including transmitting instructions to a media output device to output the noise burst.
15. A tangible computer readable storage medium comprising instructions which, when executed, cause a machine to at least:
determine a frequency spectrum of a noise burst received with a microphone the noise burst converted to a digital signal with a meter communicatively coupled to the microphone;
compute a variance of a magnitude of at least one of a first frequency band associated with first media or a second frequency band associated with second media, the first and second frequency bands corresponding to the digital signal representative of the frequency spectrum; and
determine, based on the computed variance and at least one of a first mapping for the first frequency band or a second mapping for the second frequency band, a recovery rate associated with at least one of watermark extraction or signature generation performed on an audio signal of at least one of the first or second frequency band corresponding to the first and second media, respectively, received with the microphone, the recovery rate corresponding to a placement of the microphone; and
output an alert corresponding to the recovery rate to a user interface.
16. The computer readable storage medium of claim 15 , wherein the instructions, when executed, cause the machine to map the computed variance to a detection value representative of a percentage of detections of at least one of the watermark or the signature corresponding to at least one of the first frequency band or the second frequency band.
17. The computer readable storage medium of claim 16 , wherein the instructions, when executed, cause the machine to determine the recovery rate based on at least one of the first or second mapping.
18. The computer readable storage medium of claim 15 , wherein the microphone is associated with the meter.
19. The computer readable storage medium of claim 15 , wherein the noise burst is output by at least one of a media output device or speaker corresponding to the media output device.
20. The computer readable storage medium of claim 15 , wherein the instructions cause the machine to transmit instructions to a media output device to output the noise burst.