Methods and apparatuses for performing adaptive equalization of microphone arrays

• US 9,641,935 B1
• Filed: 12/09/2015
• Issued: 05/02/2017
• Est. Priority Date: 12/09/2015
• Status: Active Grant

• Current Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Original Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Inventors: Ivanov, Plamen A
• Primary Examiner(s): Kim, Paul S
• Assistant Examiner(s): FALEY, KATHERINE A
• Application Number:
  US14/963,913
• Time in Patent Office: 510 Days
• Field of Search: 381 92
• CPC Class Codes: H03G 5/165 Equalizers; Volume or gain control in limited frequency bands
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 3/04 for correcting frequency response

Abstract

Configuring an adaptive microphone array to gather signals from a main lobe of the array, and configuring the array to reduce side interference gathered from sources that are not situated within the main lobe. A memory stores test signals gathered by the array in an anechoic chamber, a free-field environment, or other echo, interference and noise-minimized acoustic environment. Signals gathered in real time are processed to provide a preliminary output and preliminary weights. The test signals are retrieved from memory. The preliminary weights are applied to the test signals to provide equalizer weights. The equalizer weights and the preliminary output generate an equalized output that minimizes degradations resulting from side interference reduction.

Claims

1. A method comprising:

configuring a real-time adaptive microphone array to gather signals from one or more desired directions in a main lobe of the array;

configuring the array to reduce side interference gathered from one or more sources of acoustic energy that are not situated within the main lobe of the array;

configuring a computer-readable memory to store one or more test signals;

processing one or more signals gathered in real time to provide a preliminary output signal and a set of preliminary weights;

retrieving the one or more test signals from the computer-readable memory;

modeling a degradation in the gathered signals from the adaptive microphone array by applying the set of preliminary weights to the one or more test signals to provide a set of equalizer weights; and

minimizing or reducing the modeled degradation in the gathered signals by processing the set of equalizer weights and the preliminary output signal to generate an equalized output signal.

2. The method of claim 1 further comprising gathering the one or more test signals in a test environment comprising an anechoic chamber, a free-field environment, or another echo, interference and noise-minimized acoustic environment.

3. The method of claim 2 further comprising obtaining the one or more test signals using a source of white noise, a source of pink noise, a test signal having a spectral content similar or identical to that of a desired target signal, a multi-tone signal, a pseudospeech signal, or any of various combinations thereof.

4. The method of claim 1 further comprising collecting an initial set of signals for the one or more test signals using a mirrored adaptive microphone array.

5. The method of claim 4 further comprising selecting a first set of microphones for the real-time adaptive microphone array and selecting a second set of microphones for the mirrored adaptive microphone array.

6. The method of claim 5 wherein the second set of microphones comprises a representative set provided by one representative device.

7. The method of claim 1 further comprising using a single reference test microphone for collecting an initial set of signals for the one or more test signals.

8. An apparatus comprising:

a real-time adaptive microphone array configured to gather signals from one or more desired directions in a main lobe of the array, and configured to reduce side interference gathered from one or more sources of acoustic energy that are not situated within the main lobe of the array; and

a computer-readable memory, operatively coupled to the array, and configured to store one or more test signals gathered by the array;

wherein the real-time adaptive microphone array further comprises a processing mechanism for;

processing one or more signals gathered in real time to provide a preliminary output signal and a set of preliminary weights;

retrieving the one or more test signals from the computer-readable memory;

modeling a degradation in the gathered signals from the adaptive microphone array by applying the set of preliminary weights to the one or more test signals to provide a set of equalizer weights; and

minimizing or reducing the modeled degradation in the gathered signals by processing the set of equalizer weights and the preliminary output signal to generate an equalized output signal.

9. The apparatus of claim 8 wherein the stored one or more test signals are obtained from a test environment comprising an anechoic chamber, a free-field environment, or another echo, interference and noise-minimized acoustic environment.

10. The apparatus of claim 9 wherein the stored one or more test signals are obtained using a source of white noise, a source of pink noise, a test signal having a spectral content similar or identical to that of a desired target signal, a multi-tone signal, a pseudospeech signal, or any of various combinations thereof.

11. The apparatus of claim 8 further comprising a mirrored adaptive microphone array, configured for being operatively coupled to the computer-readable memory, for collecting an initial set of signals for the one or more test signals.

12. The apparatus of claim 11 wherein the real-time adaptive microphone array comprises a first set of microphones and the mirrored adaptive microphone array comprises a second set of microphones.

13. The apparatus of claim 12 wherein the second set of microphones comprises a representative set provided by one representative device.

14. The apparatus of claim 8 further comprising a single reference test microphone for collecting an initial set of signals for the one or more test signals.

15. A non-transitory computer-readable memory encoded with a computer program comprising computer readable instructions recorded thereon for execution of a method that includes:

configuring a real-time adaptive microphone array to gather signals from one or more desired directions in a main lobe of the array;

configuring the array to reduce side interference gathered from one or more sources of acoustic energy that are not situated within the main lobe of the array;

configuring a computer-readable memory to store one or more test signals;

processing one or more signals gathered in real time to provide a preliminary output signal and a set of preliminary weights;

retrieving the one or more test signals from the computer-readable memory;

modeling a degradation in the gathered signals from the adaptive microphone array by applying the set of preliminary weights to the one or more test signals to provide a set of equalizer weights; and

minimizing or reducing the modeled degradation in the gathered signals by processing the set of equalizer weights and the preliminary output signal to generate an equalized output signal.

16. The non-transitory computer-readable memory of claim 15 further comprising instructions for gathering the one or more test signals in a test environment comprising an anechoic chamber, a free-field environment, or another echo, interference and noise-minimized acoustic environment.

17. The non-transitory computer-readable memory of claim 16 further comprising instructions for obtaining the one or more test signals using a source of white noise, a source of pink noise, a test signal having a spectral content similar or identical to that of a desired target signal, a multi-tone signal, a pseudospeech signal, or any of various combinations thereof.

18. The non-transitory computer-readable memory of claim 15 further comprising instructions for using a mirrored adaptive microphone array to collect an initial set of signals for the one or more test signals.

19. The non-transitory computer-readable memory of claim 18 further comprising instructions for selecting a first set of microphones for the real-time adaptive microphone array, and for selecting a second set of microphones for the mirrored adaptive microphone array.

20. The non-transitory computer-readable memory of claim 19 further comprising instructions for selecting one representative device for implementing the second set of microphones.