Processing signals

• US 9,111,543 B2
• Filed: 12/15/2011
• Issued: 08/18/2015
• Est. Priority Date: 11/25/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Skype S.Ã R.L. (Microsoft Corporation)
• Inventors: hgren, Per
• Primary Examiner(s): KIM, PAUL
• Application Number:
  US13/327,308
• Publication Number:
  US 20130136274A1
• Time in Patent Office: 1,342 Days
• Field of Search: 381/92, 381/122, 381/94.1, 381/91, 381/94.7, 381/313, 381/71.1, 381/94.2, 381/56, 381/66, 381/94.3, 704/205, 704/225, 704/226
• US Class Current: 1/1
• CPC Class Codes: G10L 2021/02082 the noise being echo, reverberation of the speech
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: G10L 21/02 Speech enhancement, e.g. noise reduction or echo cancellation reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08
• CPC Class Codes: H04R 2430/20 Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic H04R2203/12 takes precedence
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Method, device and computer program product for processing signals. Signals are received at a plurality of sensors of the device. The initiation of a signal state in which signals of a particular type are received at the plurality of sensors is determined. Responsive to the determining of the initiation of the signal state, data indicating beamformer coefficients to be applied by a beamformer of the device is retrieved from data storage means, wherein the indicated beamformer coefficients are determined so as to be suitable for application to signals received at the sensors in the signal state. The beamformer applies the indicated beamformer coefficients to the signals received at the sensors in the signal state, thereby generating a beamformer output.

Claims

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

receiving signals at a plurality of sensors of the device;

determining the initiation of an echo signal state in which signals including echo signals are received at the plurality of sensors;

responsive to the determining the initiation of the echo signal state, retrieving, from a data store, data indicating beamformer coefficients to be applied by a beamformer of the device, the indicated beamformer coefficients being determined so as to be suitable for application to the signals received at the sensors in the echo signal state; and

the beamformer applying the indicated beamformer coefficients to the signals received at the sensors in the echo signal state to generate a beamformer output.

2. The method of claim 1 wherein prior to the initiation of the echo signal state the device operates in a non-echo signal state in which the beamformer applies other beamformer coefficients which are suitable for application to the signals received at the sensors in the non-echo signal state, and wherein the method further comprises storing the other beamformer coefficients in the data store responsive to the determining the initiation of the echo signal state.

3. The method of claim 2 further comprising:

determining the initiation of the non-echo signal state;

responsive to determining the initiation of the non-echo signal state, retrieving, from the data store, data indicating the other beamformer coefficients; and

the beamformer applying the indicated other beamformer coefficients to the signals received at the sensors in the non-echo signal state, thereby generating the beamformer output.

4. The method of claim 3 further comprising, responsive to the determining the initiation of the non-echo signal state, storing, in the data store, data indicating the beamformer coefficients applied by the beamformer prior to the initiation of the non-echo signal state.

5. The method of claim 1 wherein the sensors are microphones for receiving audio signals and wherein the device comprises an audio output block for outputting audio signals in a communication event, wherein the audio signals are echo audio signals output from the audio output block in the echo signal state.

6. The method of claim 2 wherein the non-echo signal state is a state in which echo audio signals are not significantly received at the sensors wherein the sensors are microphones.

7. The method of claim 1 wherein the determining the initiation of the echo signal state is performed before the echo signal state is initiated.

8. The method of claim 5 wherein the determining the initiation of the echo state comprises determining output activity of the audio output block in the communication event.

9. The method of claim 1 wherein the determining the initiation of the echo signal state comprises determining that echo signals are received at the sensors.

10. The method of claim 1 wherein the beamformer applying the indicated beamformer coefficients comprises smoothly adapting the beamformer coefficients applied by the beamformer until they match the indicated beamformer coefficients.

11. The method of claim 1 wherein the beamformer applying the indicated beamformer coefficients comprises performing a weighted sum of an old beamformer output determined using old beamformer coefficients which were applied by the beamformer prior to the determining the initiation of the echo signal state, and a new beamformer output determined using the indicated beamformer coefficients.

12. The method of claim 11 further comprising smoothly adjusting the weight used in the weighted sum, such that the weighted sum smoothly transitions between the old beamformer output and the new beamformer output.

13. The method of claim 1 further comprising adapting the beamformer coefficients based on the signals received at the sensors such that the beamformer applies suppression to undesired signals received at the sensors.

14. The method of claim 1 wherein the data indicating the beamformer coefficients is the beamformer coefficients.

15. The method of claim 1 wherein the retrieved data indicating the beamformer coefficients comprises a measure of the signals received at the sensors, wherein the measure is related to the beamformer coefficients using a predetermined function.

16. The method of claim 15 further comprising computing the beamformer coefficients using the measure included in the retrieved data and the predetermined function.

17. The method of claim 16 further comprising smoothly adapting the measure to thereby smoothly adapt the beamformer coefficients applied by the beamformer.

18. The method of claim 1 further comprising using the beamformer output to represent the signals received at the plurality of sensors for further processing within the device.

19. The method of claim 18 wherein the beamformer output is used by the device in a communication event.

20. The method of claim 1 further comprising applying echo cancellation to the beamformer output.

21. The method of claim 1 wherein the signals are one of:

audio signals, general broadband signals, general narrowband signals, radar signals, sonar signals, antenna signals, radio waves, or microwaves.

22. A device for processing signals, the device comprising:

a beamformer;

a plurality of sensors for receiving signals; and

a processing system configured to perform operations comprising;

determining the initiation of an echo signal state in which signals including echo signals are received at the plurality of sensors; and

retrieving from a data store, responsive to the determining the initiation of the echo signal state, data indicating beamformer coefficients to be applied by the beamformer, the indicated beamformer coefficients being determined so as to be suitable for application to the signals received at the sensors in the echo signal state;

the beamformer configured to perform operations comprising;

applying the indicated beamformer coefficients to the signals received at the sensors in the echo signal state; and

generating a beamformer output.

23. The device of claim 22 further comprising the data store.

24. The device of claim 22 wherein the sensors are microphones for receiving audio signals and the device further comprising an audio output block for outputting audio signals in a communication event, wherein the echo signals are echo audio signals output from the audio output block in the echo signal state.

25. The device of claim 22 further comprising an echo canceller configured to be applied to the beamformer output.

26. A beamformer for processing signals received at a plurality of signal sensors, the beamformer configured to:

receive signals from the plurality of sensors;

determine the initiation of an echo signal state in which signals including echo signals are received at the plurality of sensors;

responsive to the determination of the initiation of the echo signal state, retrieve, from a data store, data indicating beamformer coefficients to be applied, the indicated beamformer coefficients being determined so as to be suitable for application to the signals received at the sensors in the echo signal state; and

apply the indicated beamformer coefficients to the signals received at the sensors in the echo signal state to generate a beamformer output.