Systems, methods, and apparatus for spatially directive filtering

Patent metadata

Field	Value
Publication number	US-9291697-B2
Application number	US-201313835139-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Apr 13, 2012
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Systems, methods, and apparatus are described for applying, based on angles of arrival of source components relative to the axes of different microphone pairs, a spatially directive filter to a multichannel audio signal to produce an output signal.

First claim

What is claimed is:

1. A method of processing a multichannel audio signal, said method comprising:
calculating, by an apparatus, a first angle of arrival, relative to an axis of a first pair of microphones, for a first source component;
calculating, by the apparatus, a second angle of arrival, relative to an axis of a second pair of microphones, for the first source component;
based on said first angle of arrival and said second angle of arrival, applying, by the apparatus, a spatially directive filter, based on a first pairwise steering vector formed by the calculated first angle of arrival relative to the axis of the first pair of microphones and a second pairwise steering vector formed by the calculated second angle of arrival relative to the axis of the second pair of microphones, to the multichannel audio signal to produce an output signal.

2. The method according to claim 1 , wherein said calculated first angle of arrival for the first source component is different than said calculated second angle of arrival for the first source component.

3. The method according to claim 1 , wherein said axis of the first pair of microphones is neither parallel to nor coincident with said axis of the second pair of microphones.

4. The method according to claim 1 , wherein said calculating the first angle of arrival is based on information from a first pair of channels of the multichannel audio signal and said calculating the second angle of arrival is based on information from a second pair of channels of the multichannel audio signal, and
wherein each channel of said first pair of channels is based on a signal produced by a corresponding microphone of the first pair of microphones and each channel of said second pair of channels is based on a signal produced by a corresponding microphone of the second pair of microphones.

5. The method according to claim 1 , wherein a direction of arrival of the first source component is outside a plane defined by the axis of the first pair of microphones and the axis of the second pair of microphones.

6. The method according to claim 1 , wherein one microphone of said first pair of microphones is also included in said second pair of microphones.

7. The method according to claim 1 , wherein, for each channel of the multichannel audio signal, a proportion of energy of the first source component, relative to energy of a second source component, is greater in the output signal than in said channel of the multichannel audio signal.

8. The method according to claim 1 , wherein said applying the spatially directive filter includes selecting the spatially directive filter, based on said calculated first angle of arrival and said calculated second angle of arrival, from among a plurality of spatially directive filters.

9. The method according to claim 1 , wherein said applying the spatially directive filter includes calculating a plurality of filter coefficients of the spatially directive filter, based on said calculated first angle of arrival and said calculated second angle of arrival.

10. The method according to claim 9 , wherein said calculating the plurality of filter coefficients of the spatially directive filter comprises inverting a matrix that is based on the first pairwise steering vector and the second pairwise steering vector, wherein said plurality of filter coefficients of the spatially directive filter is based on the inverted matrix.

11. The method according to claim 10 , wherein said first pairwise steering vector indicates a propagation delay of the first source component at the first pair of microphones and said second pairwise steering vector indicates a propagation delay of the first source component at the second pair of microphones.

12. The method according to claim 10 , wherein said method comprises calculating an array steering matrix such that a first column of the array steering matrix includes the first pairwise steering vector and the second pairwise steering vector, and wherein said matrix that is based on the first pairwise steering vector and the second pairwise steering vector is based on the array steering matrix.

13. The method according to claim 12 , wherein a first row of the array steering matrix corresponds to one microphone of the first pair of microphones, a second row of the array steering matrix corresponds to the other microphone of the first pair of microphones, and a third row of the array steering matrix corresponds to one microphone of the second pair of microphones.

14. The method according to claim 12 , wherein said spatially directive filter comprises a plurality of frequency-domain filters, and
wherein each of the plurality of frequency-domain filters is based on a corresponding array steering matrix, and
wherein said applying the spatially directive filter to the multichannel audio signal comprises applying each of at least some of the plurality of frequency-domain filters to a corresponding frequency component of the multichannel audio signal, and
wherein said calculating the plurality of filter coefficients of the spatially directive filter comprises determining, for each of at least some of the plurality of frequency-domain filters, whether a matrix that is based on the corresponding array steering matrix is ill-conditioned.

15. The method according to claim 1 , wherein said spatially directive filter comprises a plurality of frequency-domain filters, and
wherein said applying the spatially directive filter to the multichannel audio signal comprises, for each of at least some of the plurality of frequency-domain filters, applying the frequency-domain filter to a corresponding frequency component of the multichannel audio signal.

16. The method according to claim 1 , wherein the first pair of microphones and the second pair of microphones are part of a multi-dimensional array of microphones, wherein a first dimension of the multi-dimensional array of microphones is formed by the axis of the first pair of microphones and a second dimension of the multi-dimensional array of microphones is formed by the axis of the second pair of microphones.

17. An apparatus for processing a multichannel audio signal, said apparatus comprising:
means for calculating a first angle of arrival, relative to an axis of a first pair of microphones, for a first source component;
means for calculating a second angle of arrival, relative to an axis of a second pair of microphones, for the first source component;
means for applying, based on said first angle of arrival and said second angle of arrival, a spatially directive filter, based on a first pairwise steering vector formed by the calculated first angle of arrival relative to the axis of the first pair of microphones and a second pairwise steering vector formed by the calculated second angle of arrival relative to the axis of the second pair of microphones, to the multichannel audio signal to produce an output signal.

18. The apparatus according to claim 17 , wherein said calculated first angle of arrival for the first source component is different than said calculated second angle of arrival for the first source component.

19. The apparatus according to claim 17 , wherein said axis of the first pair of microphones is neither parallel to nor coincident with said axis of the second pair of microphones.

20. The apparatus according to claim 17 , wherein said means for calculating the first angle of arrival is configured to calculate the first angle of arrival based on information from a first pair of channels of the multi

Assignees

• Qualcomm Inc

Inventors

• Kim Lae-Hoon
• Visser Erik

Classifications

• G01S3/80 Primary

  using ultrasonic, sonic or infrasonic waves · CPC title

• G01S15/876 Primary

  Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector (G01S15/872 takes precedence) · CPC title

• G01S5/186

  Determination of attitude (using inertial means G01C9/00; control of attitude G05D1/49) · CPC title

• G01S5/18

  using ultrasonic, sonic or infrasonic waves · CPC title

• G06F3/0484

  for the control of specific functions or operations, e.g. selecting or manipulating an object, an image or a displayed text element, setting a parameter value or selecting a range · CPC title