Processing audio signals

• US 9,042,575 B2
• Filed: 12/30/2011
• Issued: 05/26/2015
• Est. Priority Date: 12/08/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Skype S.Ã R.L. (Microsoft Corporation)
• Inventors: Sorensen, Karsten Vandborg
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): SUTHERS, DOUGLAS JOHN
• Application Number:
  US13/341,610
• Publication Number:
  US 20130148821A1
• Time in Patent Office: 1,243 Days
• Field of Search: 381/92, 381/80, 381/122, 381/66, 381/82, 381/83, 381/93, 381/89
• US Class Current: 381/93
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407

Abstract

A method, device and computer program product for processing audio signals, the method including determining beamformer filter coefficients to be applied to the audio signals; applying the beamformer filter coefficients to the audio signals; outputting the filtered audio signals from an audio output comprising a plurality of speakers coupled with the device; and receiving at a microphone coupled with the device, the filtered audio signals output from the audio output. The filter coefficients are determined such that the filtered audio signals are suppressed when received at the microphone.

Claims

1. A method of processing audio signals at a device, the method comprising:

determining beamformer filter coefficients to be applied to the audio signals, the determining comprising;

outputting bandstop-filtered audio signals to the all but one of a plurality of speakers and an unfiltered audio signal to a remaining speaker of the plurality of the speakers; and

estimating a time delay between the remaining speaker of the plurality of the speakers and a microphone coupled to the device;

applying the determined beamformer filter coefficients to the audio signals;

outputting the beamforming-filtered audio signals to the plurality of the speakers coupled with the device; and

receiving at the microphone coupled with the device, the beamforming-filtered audio signals output from the plurality of the speakers, the filter coefficients being determined such that the beamforming-filtered audio signals are suppressed when received at the microphone.

2. The method of claim 1, further comprising determining location information from two or more estimated time delays which define a location of the microphone relative to the speakers and using the location information to determine the beamformer filter coefficients.

3. The method of claim 2, wherein the location information includes an angle and a distance of the microphone relative to the speakers.

4. The method of claim 2, comprising determining the location information in real time as the beamforming-filtered audio signals are output from the speakers.

5. The method of claim 2, wherein determining location information comprises retrieving known location information from storage at the device.

6. The method of claim 1, wherein the beamformer filter coefficients define respective filters for application to the audio signals.

7. The method of claim 6, wherein the respective filters are determined such that the filtered audio signals are in opposite phase relative to each other at the microphone at a certain frequency.

8. The method of claim 1, wherein the beamformer filter coefficients define a frequency dependent phase shift that is to be applied to the audio signals.

9. The method of claim 1, comprising receiving the audio signals which are to be processed on a single channel.

10. The method of claim 1, comprising receiving the audio signals which are to be processed on one or more independent channels.

11. A device for processing audio signals, the device comprising:

a beamformer for determining filter coefficients to be applied to the audio signals, and for applying the filter coefficients to the audio signals, the determining comprising;

outputting bandstop-filtered audio signals to the all but one of a plurality of speakers and an unfiltered audio signal to a remaining speaker of the plurality of the speakers; and

estimating a time delay between the remaining speaker of the plurality of the speakers and a microphone coupled with the device; and

an audio output configured to output the beamforming-filtered audio signals to the plurality of the speakers, said beamforming-filtered audio signals received at the microphone coupled with the device, wherein the filter coefficients are determined such that the beamforming-filtered audio signals are suppressed when received at the microphone.

12. The device of claim 11, the determining the filter coefficients comprising determining location information from two or more estimated time delays which define a location of the microphone relative to the speakers.

13. The device of claim 11, wherein the beamformer is adaptive and configured to use location information that is determined in real time as the beamforming-filtered audio signals are output from the audio output.

14. The device of claim 11, wherein the microphone is integrated into the device or the microphone is coupled to the device via a wired or wireless connection.

15. The device of claim 11, wherein the device is one of:

a television;

a mobile phone;

a personal digital assistant;

a personal computer;

or a tablet computer.

16. A computer-readable storage memory device comprising instructions for processing audio signals, the instructions executable by a processor to perform the operations comprising:

determining beamformer filter coefficients to be applied to the audio signals, the determining comprising;

outputting bandstop-filtered audio signals to all but one of a plurality of speakers and an unfiltered audio signal to a remaining speaker of the plurality of the speakers; and

estimating a time delay between the remaining speaker of the plurality of the speakers and a microphone coupled to the device;

applying the determined beamformer filter coefficients to the audio signals;

outputting the beamforming-filtered audio signals to the plurality of the speakers coupled with the device; and

receiving at the microphone coupled with the device, the beamforming-filtered audio signals output from the plurality of the speakers, the filter coefficients being determined such that the beamforming filtered audio signals are suppressed when received at the microphone.

17. The computer-readable storage memory device of claim 16, the instructions further executable to perform:

determining location information from two or more estimated time delays which define a location of the microphone relative to the speakers and using the location information to determine the beamformer filter coefficients.