Electronic apparatus for generating beamformed audio signals with steerable nulls

• US 8,433,076 B2
• Filed: 07/26/2010
• Issued: 04/30/2013
• Est. Priority Date: 07/26/2010
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Inventors: Zurek, Robert, Bastyr, Kevin, Clark, Joel, Ivanov, Plamen
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): FAHNERT, FRIEDRICH
• Application Number:
  US12/843,555
• Publication Number:
  US 20120019689A1
• Time in Patent Office: 1,009 Days
• Field of Search: 381/92, 381/94.1, 381/94.7, 381/300, 381/59, 381/86, 381/18, 381/302, 381/313, 381/312, 381/355, 381/57, 381/80, 381/81, 381/1, 381/2, 381/26, 381/91, 381/122, 381/356, 348/175, 348/231.4, 700/94
• US Class Current: 381/92
• 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
• CPC Class Codes: H04S 2400/15 Aspects of sound capture and related signal processing for recording or reproduction

Abstract

An electronic apparatus is provided having a front side and a rear side oriented in opposite directions along a first axis, and a right-side and a left-side oriented in opposite directions along a second axis that is perpendicular to the first axis. A null control signal is generated based on an imaging signal. A first microphone located near the right-side of an electronic apparatus generates a first signal and a second microphone located near the left-side of the electronic apparatus generates a second signal. The first and second signals are processed, based on the null control signal, to generate a right beamformed audio signal having a first directional pattern having at least one first null, and a left beamformed audio signal having a second directional pattern having at least one second null. A first angular location (α) of the at least one first null and a second angular location (β) of the at least one second null are steered based on the null control signal.

Claims

1. An apparatus for recording one or more subjects by a camera operator, the apparatus having a front side oriented towards the one or more subjects and a rear side oriented towards the camera operator, the front side and the rear side being oriented in opposite directions along a first axis, and a right side and a left side oriented in opposite directions along a second axis that is perpendicular to the first axis, the apparatus comprising:

a first microphone, located near the right side, that generates a first signal;

a second microphone, located near the left side, that generates a second signal;

an automated null controller that generates a null control signal based on an imaging signal;

a rear-side proximity sensor, coupled to the automated null controller, that generates a rear-side proximity sensor signal that corresponds to a distance between the camera operator and the apparatus;

a beamforming module, coupled to the first microphone, the second microphone, and the automated null controller, that processes the first signal and the second signal based on the null control signal to generate;

a right beamformed audio signal having a first directional pattern having at least one first null, and

a left beamformed audio signal having a second directional pattern having at least one second null,

wherein the first angular location (α

) of the at least one first null and the second angular location (β

) of the at least one second null is steered based on the null control signal such that the first null and the second null are oriented to cancel sound that originates from the rear side at the distance.

2. The apparatus of claim 1, further comprising:

a video camera, coupled to the automated null controller, for producing the imaging signal.

3. The apparatus of claim 2, wherein the imaging signal is based on an angular field of view of a video frame of the video camera.

4. The apparatus of claim 3, wherein the first angular location (α

) and the second angular location (β

), relative to an axis through a first microphone port and a second microphone port, increases as the angular field of view is decreased.

5. The apparatus of claim 3, wherein the first angular location (α

) and the second angular location (β

), relative to an axis through a first microphone port and a second microphone port, decreases as the angular field of view is increased.

6. The apparatus of claim 2, wherein the imaging signal is based on focal distance for the video camera.

7. The apparatus of claim 6, wherein the first angular location (α

) and the second angular location (β

), relative to an axis through a first microphone port and a second microphone port, increases as the focal distance is increased.

8. The apparatus of claim 6, wherein the first angular location (α

) and the second angular location (β

), relative to an axis through a first microphone port and a second microphone port, decreases as the focal distance is decreased.

9. The apparatus of claim 2, wherein the imaging signal is based on a zoom control signal for the video camera that is controlled by a user interface.

10. The apparatus of claim 9, wherein the zoom control signal for the video camera is a digital zoom control signal.

11. The apparatus of claim 9, wherein the zoom control signal for the video camera is an optical zoom control signal.

12. The apparatus of claim 9, wherein the first angular location (α

) and the second angular location (β

), relative to an axis through a first microphone port and a second microphone port, increases as the zoom control signal is increased.

13. The apparatus of claim 9, wherein the first angular location (α

) and the second angular location (β

), relative to an axis through a first microphone port and a second microphone port, decreases as the zoom control signal is decreased.

14. The apparatus of claim 1, further comprising:

a predetermined distance value stored in memory, wherein the null control signal is based on the predetermined distance value.

15. The apparatus of claim 1, wherein the at least one first null comprises a first null point oriented towards the front side and a second null point oriented toward the rear side, and wherein the at least one second null comprises a third null point oriented towards the front side and a fourth null point oriented toward the rear side.

16. The apparatus of claim 15:

wherein the imaging signal is based on the rear-side proximity sensor signal.

17. A method in an apparatus for recording one or more subjects oriented towards a front side of the apparatus by a camera operator oriented towards a rear side of the apparatus, the front side and the rear side being oriented in opposite directions along a first axis, the method comprising:

generating a null control signal based on an imaging signal;

generating a rear-side proximity sensor signal that corresponds to a distance between the camera operator and the apparatus;

processing, based on the null control signal, a first signal from a first microphone and a second signal from a second microphone located left of the first microphone;

generating a right beamformed audio signal having a first directional pattern having at least one first null; and

generating a left beamformed audio signal having a second directional pattern having at least one second null,

wherein a first angular location (α

) of the at least one first null and a second angular location (β

) of the at least one second null is steered based on the null control signal such that the first null and the second null are oriented to cancel sound that originates from the rear side at the distance.

18. The method of claim 17, further comprising:

generating the imaging signal at a video camera, wherein the imaging signal is based on one or more of;

an angular field of view of a video frame of the video camera, a focal distance for the video camera, the rear-side proximity sensor signal, and a zoom control signal for the video camera.

19. The method of claim 17 wherein the generating a right beamformed audio signal comprises:

setting the first angular location (α

) to attenuate signals from audio sources to a front-left, and

where the generating a left beamformed audio signal comprises;

setting the second angular location (β

) to attenuate signals from audio sources to a front-right.