Dynamic beamformer processing for acoustic echo cancellation in systems with high acoustic coupling

• US 8,942,382 B2
• Filed: 03/22/2012
• Issued: 01/27/2015
• Est. Priority Date: 03/22/2011
• Status: Active Grant

• Current Assignee: mh acoustics LLC
• Original Assignee: mh acoustics LLC
• Inventors: Elko, Gary W., Gaensler, Tomas F., Diethorn, Eric J., Meyer, Jens M.
• Primary Examiner(s): Zhang, Leshui
• Application Number:
  US13/426,761
• Publication Number:
  US 20120243698A1
• Time in Patent Office: 1,041 Days
• Field of Search: 381/66, 381/313, 381/317, 381/318, 381/320, 381/321, 381/71.1, 381/71.2, 381/71.3, 381/71.4, 381/71.5, 381/71.6, 381/71.7, 381/71.11, 381/71.12, 381/74, 381/79, 381/83, 381/86, 381/95, 381/91, 381/92, 381/93, 381/94.1, 381/96, 381/97, 381/98, 381/119, 381/121, 381/122, 455/569.1, 455/569.2, 455/570, 455/114.2, 455/136, 455/296, 455/297, 37940601-40616, 700/94
• US Class Current: 381/66
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

Near-end equipment for a communication channel with far-end equipment. The near-end equipment includes at least one loudspeaker, at least two microphones, a beamformer, and an echo canceller. The communication channel may be in one of a number of communication states including Near-End Only state, Far-End Only state, and Double-Talk state. In one embodiment, when the echo canceller determines that the communication channel is in either the Far-End Only state or the Double-Talk state, the beamformer is configured to generate a nearfield beampattern signal that directs a null towards a loudspeaker. When the echo canceller detects the Near-End Only state, the beamformer is configured to generate a farfield beampattern signal that optimizes reception of acoustic signals from the near-end audio source. Using different beamformer processing for different communication states allows echo cancellation processing to be more successful at reducing echo in the signal transmitted to the far-end equipment.

Claims

1. Near-end equipment for a near-end audio source communicating with a far-end equipment via an audio communication channel, the near-end equipment comprising:

a beamformer configured to receive two or more microphone signals generated by two or more local microphones and generate one or more beampattern signals; and

an echo canceller configured to

(i) receive the one or more beampattern signals from the beamformer and an incoming signal from the far-end equipment that is applied to one or more local loudspeakers,

(ii) determine an active communication state for the audio communication channel,

(iii) select a beampattern for the beamformer based on the determined active communication state, and

(iv) apply echo-cancellation processing to a beampattern signal corresponding to the selected beampattern for the beamformer, to generate an outgoing signal to be transmitted to the far-end equipment,

wherein;

active communication states comprise a near-end only talking state, a far-end only talking state, and a double-talk state;

one or more beampatterns comprise a first beampattern and a second beampattern different from the first beampattern;

the first beampattern has at least one near-field null corresponding to the one or more local loudspeakers and a far-field pattern that does not contain any nulls;

the second beampattern optimizes reception of acoustic signals from the near-end audio source;

when the echo canceller determines that the active communication state is the far-end only talking state or the double-talk state, the echo canceller selects the first beampattern;

when the echo canceller determines that the active communication state is the near-end only taling state, the echo canceller selects the second beampattern;

wherein the beamformer is configured to generate a first beampattern signal for a first communication state; and

the echo canceller is configured to

(i) detect a change from the first communication state to a second communication state different from the first communication state and

(ii) control the beamformer to be re-configured to generate a second beampattern signal different from the first beampattern signal for the second communication state.

2. The near-end equipment of claim 1, wherein:

the beamformer simultaneously generates first and second beampattern signals corresponding to the first and second beampatterns; and

the echo canceller selects one of the first and second beampattern signals as the beampattern signal corresponding to the selected beampattern.

3. The near-end equipment of claim 1, wherein the near-end equipment further comprises the one or more local loudspeakers and the two or more local microphones.

4. The near-end equipment of claim 3, wherein at least one of the two or more local microphones is

(i) located inside housing of one of the one or more local loudspeakers and

(ii) configured to be used to reduce audio coupling between the one or more local loudspeakers and the two or more local microphones during at least one determined active communication state.

5. The near-end equipment of claim 1, wherein the beamformer is configured to concurrently generate different beampattern signals for two or more different frequency bands of the two or more microphone signals.

6. The near-end equipment of claim 5, wherein the beamformer is configured to concurrently generate:

a first beampattern signal for a first frequency band of the two or more microphone signals having a null directed towards a first loudspeaker; and

a second, different beampattern signal for a second, different frequency band of the two or more microphone signals having a null directed towards a second, different loudspeaker.

7. The near-end equipment of claim 1, wherein:

the one or more local loudspeakers comprises at least a first local loudspeaker and a second local loudspeaker; and

the beamformer is configured to generate a beampattern signal having a first null directed towards the first local loudspeaker and a second null directed towards the second local loudspeaker.

8. The near-end equipment of claim 1, wherein:

there are two or more local loudspeakers; and

the near-end equipment is configured to control the two or more local loudspeakers to generate a loudspeaker beampattern based on the determined active communication state.

9. The near-end equipment of claim 8, wherein the near-end equipment is configured to steer the loudspeaker beampattern away from the two or more local microphones for at least one determined active communication state.

10. The near-end equipment of claim 1, wherein the far-field pattern of the first beampattern is a far-field omnidirectional pattern.