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1. EP2727378 - AUDIO PLAYBACK SYSTEM MONITORING

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

Claims

1. A method for monitoring status of a set of N speakers (L, C, R) in a playback environment (1), where N is a positive integer, said method including steps of:

(a) playing back an audiovisual program whose soundtrack has N channels, each of the N channels corresponding to a respective speaker feed for a respective corresponding speaker, by emitting sound, determined by the program, from the speakers in response to driving each of the speakers with its respective speaker feed;

(b) obtaining audio data indicative of a status signal captured by at least one microphone (3), wherein the at least one microphone is positioned in the playback environment such that sound emitted from the N speakers can be captured by the at least one microphone; and

(c) processing the audio data to perform a status check on each of the N speakers, including by comparing, for each speaker-microphone pair, the status signal captured by the respective microphone to a corresponding template signal, wherein the template signal is indicative of a response of a template microphone to a playback by the respective speaker in the playback environment at an initial time, of the channel of the soundtrack corresponding to said speaker,

characterized in that step (c) includes:

determining, for each speaker-microphone pair, a cross-correlation of the template signal for said speaker and microphone with the status signal for said microphone;

determining, for each speaker-microphone pair, a cross-correlation power spectrum or a smoothed cross-correlation power spectrum from the cross-correlation for said speaker-microphone pair; and

identifying, for each speaker-microphone pair, a deviation of the determined cross-correlation power spectrum for said speaker-microphone pair from zero amplitude spectrum by means of a metric of the cross-correlation power spectrum; or

characterized in that step (c) includes:

for each speaker-microphone pair, applying a bandpass filter to the template signal for said speaker and microphone, and to the status signal for said microphone, thereby determining a bandpass filtered template signal and a bandpass filtered status signal;

determining, for each said speaker-microphone pair, a cross-correlation of the bandpass filtered template signal for said speaker and microphone with the bandpass filtered status signal for said microphone;

identifying, for each speaker-microphone pair, a deviation of the cross-correlation power spectrum or a smoothed cross-correlation power spectrum for said speaker-microphone pair from zero amplitude spectrum by means of a metric of the cross-correlation power spectrum; or

characterized in that step (c) includes:

for each speaker-microphone pair, applying a bandpass filter to the corresponding template signal, and to the status signal captured by the respective microphone, thereby determining a bandpass filtered template signal and a bandpass filtered status signal;

determining, for each said speaker-microphone pair, a sequence of cross-correlations of the bandpass filtered status signal captured by the respective microphone with the corresponding bandpass filtered template signal, wherein each of the cross-correlations is a cross-correlation of a segment of the bandpass filtered status signal captured by the respective microphone with the corresponding bandpass-filtered template signal; and

identifying a difference between the bandpass-filtered status signal captured by the respective microphone and the corresponding bandpass filtered template signal, from an average of the cross-correlations.


  2. The method of claim 1, wherein the audiovisual program is a movie trailer.
  3. The method of claim 2, wherein the playback environment is a movie theater, and step (a) includes the step of playing back the trailer in the presence of an audience in the movie theater.
  4. The method of claim 1, wherein the at least one microphone is positioned at at least substantially the same position in the environment as the template microphone was positioned at the initial time.
  5. The method of claim 1, wherein one microphone is positioned in the playback environment and the audio data obtained is indicative of a status signal captured by said microphone in the playback environment during playback, and the template microphone is said microphone.
  6. The method of claim 1, said method also including the steps of:

for each speaker-microphone pair consisting of one of the speakers and one template microphone of a set of template microphones in the playback environment, determining an impulse response of the speaker by measuring sound emitted from said speaker at the initial time with the template microphone; and

for each of the channels, determining the convolution of the speaker feed for said channel with the impulse response of the speaker which is driven with said speaker feed, wherein said convolution determines the template signal employed in step (c) for the speaker-microphone pair employed to determine said convolution.


  7. The method of claim 1, said method also including a step of:
for each speaker-microphone pair consisting of one of the speakers and one template microphone of a set of template microphones in the playback environment, driving the speaker at the initial time with the speaker feed which drives said speaker, and measuring the sound emitted from said speaker in response to said speaker feed with the template microphone, wherein the measured sound determines the template signal employed in step (c) for said speaker-microphone pair.
  8. The method of claim 1, said method also including the steps of:

(d) for each speaker-microphone pair consisting of one of the speakers and one template microphone of a set of template microphones in the playback environment, determining an impulse response of the speaker by measuring sound emitted from said speaker at the initial time with the template microphone;

(e) for each of the channels, determining the convolution of the speaker feed for said channel with the impulse response of the speaker which is driven with said speaker feed in step (a); and

(f) for each of the channels, determining a bandpass filtered convolution by applying a bandpass filter to the convolution determined in step (e) for said channel, wherein said bandpass filtered convolution determines the template signal employed in step (c) for the speaker-microphone pair employed to determine said bandpass filtered convolution.


  9. The method of claim 1, said method also including the steps of:

(d) for each speaker-microphone pair consisting of one of the speakers and one template microphone of a set of template microphones in the playback environment, driving the speaker at the initial time with the speaker feed which drives said speaker in step (a), and employing the template microphone to generate a microphone output signal indicative of the sound emitted from said speaker in response to said speaker feed; and

(e) for each speaker-microphone pair, determining a bandpass filtered microphone output signal by applying a bandpass filter to the microphone output signal generated in step (d), wherein said bandpass filtered microphone output signal determines the template signal employed in step (c) for the speaker-microphone pair employed to determine said bandpass filtered microphone output signal.


  10. A system for monitoring status of a set of N speakers (L, C, R) in a playback environment (1), where N is a positive integer, said system including:

at least one microphone (3), wherein the at least one microphone is positioned in the playback environment such that sound emitted from the N speakers can be captured by the at least one microphone; and

a processor (2) coupled to each of the microphones, wherein the processor is configured to process audio data to perform a status check on each speaker, including by comparing, for each speaker-microphone pair, a status signal captured by the respective microphone to a corresponding template signal,

wherein the audio data are indicative of the status signal captured by each microphone of the set of microphones during playback of an audiovisual program whose soundtrack has N channels, each of the N channels corresponding to a respective speaker feed for a respective corresponding speaker, by emitting sound, determined by the program, from the speakers in response to driving each of the speakers with its respective speaker feed;

wherein each template signal is indicative of a response of a template microphone to a playback by the respective speaker of the speaker-microphone pair in the playback environment at an initial time, of a channel of the soundtrack corresponding to said speaker; and

characterized in that the processor is configured to:

determine, for each speaker-microphone pair, a cross-correlation of the template signal for said speaker and microphone with the status signal for said microphone;

determine, for each speaker-microphone pair, a cross-correlation power spectrum or a smoothed cross-correlation power spectrum from the cross-correlation for said speaker-microphone pair; and

identify, for each speaker-microphone pair, a deviation of the determined cross-correlation power spectrum for said speaker-microphone pair from zero amplitude spectrum by means of a metric of the cross-correlation power spectrum; or

characterized in that the processor is configured to:

for each speaker-microphone pair, apply a bandpass filter to the template signal for said speaker and microphone, and to the status signal for said microphone, thereby determining a bandpass filtered template signal and a bandpass filtered status signal;

determine, for each said speaker-microphone pair, a cross-correlation of the bandpass filtered template signal for said speaker and microphone with the bandpass filtered status signal for said microphone;

identify, for each speaker-microphone pair, a deviation of the cross-correlation power spectrum or a smoothed cross-correlation power spectrum for said speaker-microphone pair from zero amplitude spectrum by means of a metric of the cross-correlation power spectrum; or

characterized in that the processor is configured to:

for each speaker-microphone pair, apply a bandpass filter to the corresponding template signal, and to the status signal captured by the respective microphone, thereby determining a bandpass filtered template signal and a bandpass filtered status signal;

determine, for each said speaker-microphone pair, a sequence of cross-correlations of the bandpass filtered status signal captured by the respective microphone with the corresponding bandpass filtered template signal, wherein each of the cross-correlations is a cross-correlation of a segment of the bandpass filtered status signal captured by the respective microphone with the corresponding bandpass-filtered template signal; and

identify a difference between the bandpass-filtered status signal captured by the respective microphone and the corresponding bandpass filtered template signal, from an average of the cross-correlations.