Transformation inversion to reduce the effect of room acoustics

• US 9,615,171 B1
• Filed: 07/02/2012
• Issued: 04/04/2017
• Est. Priority Date: 07/02/2012
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Salvador, Stan W., O'Neill, Jeffrey C.
• Primary Examiner(s): Hudspeth, David
• Assistant Examiner(s): Nguyen, Timothy
• Application Number:
  US13/540,435
• Time in Patent Office: 1,737 Days
• Field of Search: 704203
• 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 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Embodiments of systems and methods are described for inverting transformations of signals due to room acoustics. In some implementations, a transformation of a calibration signal from a particular location in a room may be determined. From this transformation, an inverse transformation may be determined and the inverse transformation may be applied to a speech signal received from a similar location.

Claims

1. A non-transitory, computer-readable medium having computer-executable instruction sets, the computer-executable instruction sets comprising:

a signal receiving instruction set configured to cause a computing system to receive a transformed calibration signal generated by a microphone that converted a sound wave, wherein the transformed calibration signal corresponds to a transformation of a predetermined calibration signal, the predetermined calibration signal comprising acoustic information;

a location determination instruction set configured to cause the computing system to determine a location of an emitting device that emits audio output corresponding to the predetermined calibration signal;

a transformation estimation instruction set configured to cause the computing system to estimate a first inverse transformation using the transformed calibration signal and information about the predetermined calibration signal;

an information storing instruction set configured to cause the computing system to store information about the first inverse transformation and information about the location of the emitting device;

the signal receiving instruction set configured to cause the computing system to receive a transformed speech signal generated by the microphone, wherein the transformed speech signal corresponds to an utterance spoken by a user;

the location determination instruction set configured to cause the computing system to determine a location of the user based on the speech signal spoken by the user;

a transformation selection instruction set configured to cause the computing system to select a second inverse transformation, stored in advance by the information estimation set, based on the location of the user; and

a signal estimation instruction set configured to cause the computing system to apply the second inverse transformation to the transformed speech signal.

2. The non-transitory, computer-readable medium of claim 1, wherein the first inverse transformation is an approximation of an exact inverse transformation and wherein the first inverse transformation is estimated using a Wiener filter.

3. The non-transitory, computer-readable medium of claim 1, wherein the second inverse transformation is the first inverse transformation.

4. The non-transitory, computer-readable medium of claim 1, wherein the location determination instruction set is further configured to determine at least one of an angle and a distance between the emitting device and the microphone.

5. A computer-implemented method comprising:

receiving a predetermined calibration signal, the predetermined calibration signal comprising acoustic information;

estimating a first transformation using the predetermined calibration signal;

adding the first transformation to a plurality of predetermined transformations;

receiving, at a microphone, a transformed signal from a source;

determining a location associated with the source based on the transformed signal;

selecting a previously-stored transformation corresponding to the location of the source from the plurality of predetermined transformations, wherein each transformation of the plurality of predetermined transformations corresponds to a respective location; and

estimating a signal based upon the previously-stored transformation and the transformed signal.

6. The computer-implemented method of claim 5, wherein the previously-stored transformation is an approximation of an exact inverse transformation.

7. The computer-implemented method of claim 5, further comprising performing speech recognition with the estimated signal.

8. The computer-implemented method of claim 5, wherein determining the location associated with the source comprises utilizing a beam forming technique.

9. The computer-implemented method of claim 5, wherein determining the location associated with the source comprises processing signals other than the transformed signal.

10. The computer-implemented method of claim 9, wherein the signals other than the transformed signal comprise one or more of a Wi-Fi signal, a Bluetooth signal, or a GPS signal.

11. The computer-implemented method of claim 5, wherein determining a location comprises determining an angle and distance between the microphone and the source.

12. The computer-implemented method of claim 5, wherein estimating the signal comprises performing a convolution of the transformed signal and the previously-stored transformation.

13. An apparatus comprising:

a microphone configured to generate;

a transformed calibration signal, wherein the transformed calibration signal comprises a transformation of a predetermined calibration signal, the predetermined calibration signal comprising acoustic information; and

a transformed speech signal, wherein the transformed speech signal corresponds to an utterance spoken by a user; and

a processor in communication with the microphone configured to;

determine a location associated with a device that emits audio output corresponding to the predetermined calibration signal;

determine a location associated with the user based at least partly on the transformed speech signal;

apply a previously-stored transformation to the transformed speech signal using the location associated with the device, the location associated with the user, the transformed calibration signal, and information about the predetermined calibration signal.

14. The apparatus of claim 13, wherein the processor is configured to determine the location associated with the device by determining at least one of an angle and a distance between the microphone and the device.

15. The apparatus of claim 13, wherein the processor is configured to apply the transformation by applying a filter.

16. The apparatus of claim 13 further comprising a receiver configured to receive an indication of a transmit time of the predetermined calibration signal.

17. The apparatus of claim 16, wherein the processor is further configured to determine a distance from the device to the microphone based upon the indication of the predetermined calibration signal transmit time.

18. The apparatus of claim 13, further comprising:

a second microphone in communication with the processor, configured to generate;

a second transformed speech signal, wherein the second transformed speech signal corresponds to the utterance spoken by the user; and

wherein the processor is configured to determine the location associated with the user by comparing a first receive time of the transformed speech signal with a second receive time of the second transformed speech signal.

19. The apparatus of claim 13, wherein the processor is further configured to estimate the transformation of the predetermined calibration signal based upon the received transformed calibration signal and information about the predetermined calibration signal.