Systems, methods, and apparatus for indicating direction of arrival

Patent metadata

Field	Value
Publication number	US-9360546-B2
Application number	US-201313834715-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Apr 13, 2012
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Systems, methods, and apparatus for projecting an estimated direction of arrival of sound onto a plane that does not include the estimated direction are described.

First claim

What is claimed is:

1. A method of indicating a direction of arrival of a sound, said method comprising:
calculating a first estimate, with respect to an axis of a first microphone array, of the direction of arrival;
calculating a second estimate, with respect to an axis of a second microphone array that is different than the axis of the first microphone array, of the direction of arrival;
determining an orientation, with reference to a world reference axis, of a device that includes the first and second microphone arrays; and
based on the first and second estimates and the determined orientation, calculating a projection of the direction of arrival onto a projection plane that does not include the direction of arrival.

2. The method according to claim 1 , wherein said sound is a component of a multichannel signal, and
wherein said multichannel signal is based on signals produced by said first microphone array and on signals produced by said second microphone array.

3. The method according to claim 1 , wherein said first estimate indicates a first angle with respect to the axis of the first microphone array, and
wherein said calculating the projection includes converting the first angle to a second angle with respect to the axis of the first microphone array,
wherein the second angle is in the projection plane and is based on at least a magnitude of the second estimate.

4. The method according to claim 3 , wherein a magnitude of the second angle is less than a magnitude of the first angle.

5. The method according to claim 3 , wherein said calculating the projection includes combining the second angle with information from the second estimate to obtain the calculated projection.

6. The method according to claim 1 , wherein the projection plane includes the axis of the first microphone array and the axis of the second microphone array.

7. The method according to claim 1 , wherein said first estimate is based on a plurality of phase differences between channels of a multichannel signal, and wherein each of said channels is based on a signal produced by a corresponding microphone of said first microphone array.

8. The method according to claim 1 , wherein the axis of the first microphone array is not orthogonal to the axis of the second microphone array.

9. The method according to claim 1 , wherein the axis of the first microphone array is at least five degrees from orthogonal to the axis of the second microphone array.

10. The method according to claim 1 , wherein said method includes estimating an angle of elevation, with reference to a plane that includes the axes of the first and second microphone arrays, of the direction of arrival.

11. The method according to claim 1 , wherein said world reference axis is one among a magnetic axis and a gravitational axis.

12. The method according to claim 1 , wherein said first microphone array includes at least three microphones, and
wherein said first estimate is based on information from signals produced by each of said at least three microphones.

13. The method according to claim 1 , wherein the sound is produced by a mouth of a human speaker.

14. The method according to claim 13 , wherein said mouth is above the plane.

15. The method according to claim 1 , wherein said method comprises indicating the projected direction of arrival in a display plane that is not more than ten degrees from parallel to the projection plane.

16. The method according to claim 1 , wherein said method comprises:
calculating a first estimate, with respect to the axis of the first microphone array, of a direction of arrival of a second sound;
calculating a second estimate, with respect to the axis of the second microphone array, of the direction of arrival of the second sound;
based on the first and second estimates of the direction of arrival of the second sound, calculating a projection of the direction of arrival of the second sound into a plane that does not include the direction of arrival of the second sound; and
producing a display image that indicates both among the projected direction of arrival of the sound and the projected direction of arrival of the second sound.

17. The method according to claim 1 , wherein said method comprises:
calculating a steering vector that is based on pair-wise phase delays; and
performing a spatially selective filtering operation on a signal that is based on a multichannel signal produced by at least one among the first and second microphone arrays,
wherein said spatially selective filtering operation is based on the calculated steering vector.

18. The method according to claim 1 , wherein:
the first estimate indicates a first angle with respect to the axis of the first microphone array;
the second estimate indicates a second angle with respect to the axis of the second microphone array; and
calculating the projection comprises:
converting the first angle to an angle in the projection plane based on the second angle and a skew angle, and
combining the converted angle with information from the second estimate to obtain the projection of the direction of arrival.

19. An apparatus for indicating a direction of arrival of a sound, said apparatus comprising:
means for calculating a first estimate, with respect to an axis of a first microphone array, of the direction of arrival;
means for calculating a second estimate, with respect to an axis of a second microphone array that is different than the first microphone array, of the direction of arrival;
means for determining an orientation, with reference to a world reference axis, of a device that includes the first and second microphone arrays; and
means for calculating, based on the first and second estimates and the determined orientation, a projection of the direction of arrival onto a projection plane that does not include the direction of arrival.

20. The apparatus according to claim 19 , wherein said sound is a component of a multichannel signal, and
wherein said multichannel signal is based on signals produced by said first microphone array and on signals produced by said second microphone array.

21. The apparatus according to claim 19 , wherein said first estimate indicates a first angle with respect to the axis of the first microphone array, and
wherein said means for calculating the projection includes means for converting the first angle to a second angle with respect to the axis of the first microphone array,
wherein the second angle is in the projection plane and is based on at least a magnitude of the second estimate.

22. The apparatus according to claim 21 , wherein a magnitude of the second angle is less than a magnitude of the first angle.

23. The apparatus according to claim 21 , wherein said means for calculating the projection includes means for combining the second angle with information from the second estimate to obtain the calculated projection.

24. The apparatus according to claim 19 , wherein the projection plane includes the axis of the first microphone array and the axis of the second microphone array.

25. The apparatus according to claim 19 , wherein said first estimate is based on a plurality of phase differences between channels of a multichannel signal, and wherein each of said channels is based on a signal produced by a corresponding microphone of said first microphone array.

26. The apparatus according to claim 19 , wherein the

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

• G01S3/8006 Primary

  Multi-channel systems specially adapted for direction-finding, i.e. having a single aerial system capable of giving simultaneous indications of the directions of different signals · CPC title

• G01S5/18

  using ultrasonic, sonic or infrasonic waves · CPC title

• G10L2021/02166

  Microphone arrays; Beamforming · CPC title