Detecting device proximities

• US 9,336,767 B1
• Filed: 03/28/2014
• Issued: 05/10/2016
• Est. Priority Date: 03/28/2014
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Barton, William Folwell, Velusamy, Kavitha, Hilmes, Philip Ryan
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): Kurr, Jason R
• Application Number:
  US14/229,454
• Time in Patent Office: 774 Days
• Field of Search: 381/71.11, 381/71.9, 381/66, 381/92, 381/303, 381/94.1, 381/110, 37938701-39201, 37940601-40616, 700/94
• US Class Current: 1/1
• CPC Class Codes: G10K 11/16 Methods or devices for protecting against, or for damping, noise or other acoustic waves in general G10K11/36 takes precedence
• CPC Class Codes: G10K 11/178 by electro-acoustically regenerating the original acoustic waves in anti-phase
• CPC Class Codes: G10K 2210/108 Communication systems, e.g. where useful sound is kept and noise is cancelled
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters
• CPC Class Codes: G10K 2210/505 Echo cancellation, e.g. multipath-, ghost- or reverberation-cancellation
• CPC Class Codes: G10L 15/34 Adaptation of a single recogniser for parallel processing, e.g. by use of multiple processors or cloud computing
• CPC Class Codes: G10L 2021/02082 the noise being echo, reverberation of the speech
• CPC Class Codes: G10L 2021/02165 Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

An audio device may be configured to produce output audio and to capture input audio for speech recognition. In some cases, a second device may also be used to capture input audio to improve isolation of input audio with respect to the output audio. In addition, acoustic echo cancellation (AEC) may be used to remove components of output audio from input signals of the first and second devices. AEC may be implemented by an adaptive filter based on dynamically optimized filter coefficients. The filter coefficients may be analyzed to detect situations in which the first and second devices are too close to each other, and the user may then be prompted to increase the distance between the two devices.

Claims

1. A first device comprising:

a microphone configured to produce a first input audio signal representing output audio produced by a speaker of a second device, wherein the first device is positioned at a distance from the second device;

an adaptive finite impulse response (FIR) filter configured to cancel the output audio from the first input audio signal based at least in part on a reference signal received from the second device and a sequence of dynamically updated filter coefficients;

a detector configured to perform acts comprising;

determining a measurement corresponding to the output audio in the first input audio signal by analyzing the sequence of dynamically updated filter coefficients;

determining that the measurement does not satisfy a criteria; and

providing a notification that one of the first and second devices should be moved to increase the distance between the first device and the second device.

2. The first device of claim 1, wherein:

the measurement comprises the distance from the second device; and

the criteria comprises a minimum distance.

3. The first device of claim 1, wherein the measurement comprises a strength of the output audio in the first input audio signal.

4. A method, comprising:

obtaining a first input audio signal representing audio received at a first device, wherein the first input audio signal represents output audio produced by a speaker of a second device;

obtaining a reference signal, wherein the second device used the reference signal to generate the output audio;

cancelling the output audio from the first input audio signal using a finite impulse response (FIR) filter corresponding to a first sequence of filter coefficients and the reference signal;

determining a measurement of the output audio in the first input audio signal by analyzing the first sequence of filter coefficients;

determining that the measurement does not satisfy a criteria; and

providing a notification to increase a distance between the first device and the second device.

5. The method of claim 4, wherein the filter coefficients are dynamically updated.

6. The method of claim 4, wherein obtaining the reference signal comprises receiving the reference signal from the second device.

7. The method of claim 4, wherein the cancelling is performed at the first device.

8. The method of claim 4, wherein the measurement comprises the distance between the first device and the second device and the given criteria comprises a minimum distance.

9. The method of claim 8, wherein determining the measurement comprises (a) identifying a peak filter coefficient in the first sequence of filter coefficients that corresponds to a direct acoustic path between the first device and the second device;

and (b) determining the distance between the first device and the second device is based on the position of the peak filter coefficient in the first sequence of filter coefficients.

10. The method of claim 4, wherein the measurement comprises a strength of the output audio in the first input audio signal.

11. The method of claim 10, wherein:

determining the measurement comprises identifying a peak coefficient in the first sequence of filter coefficients that corresponds to a direct acoustic path between the first device and the second device; and

the strength of the output audio in the first input audio signal is determined based at least in part on a magnitude of the peak coefficient.

12. The method of claim 10, further comprising determining the strength of the output audio in the first input audio signal based at least in part on filter coefficient of the first sequence of filter coefficients corresponding to a direct acoustic path between the second device and the first device.

13. The method of claim 10, further comprising determining the strength of the output audio in the first input signal based at least on part on (a) one or more coefficients of the first sequence of filter coefficients corresponding to a direct acoustic path between the second device and the first device;

and (b) one or more coefficients of the first sequence of filter coefficients corresponding to one or more reflective acoustic paths between the second device and the first device.

14. The method of claim 4, further comprising:

obtaining a second input audio signal representing audio received at the second device;

cancelling the output audio from the second input audio signal based at least in part on the reference signal and a second sequence of filter coefficients; and

wherein determining the measurement is performed as a function of the first and second sequences of filter coefficients.

15. The method of claim 14, wherein the determining the measurement comprises:

determining a first strength of the output audio in the first input audio signal by analyzing the first sequence of filter coefficients; and

determining a second strength of the output audio in the second input audio signal by analyzing the second sequence of filter coefficients.

16. The method of claim 14, wherein the determining the measurement comprises:

calculating a first ratio of direct versus reflective strengths of the output audio in the first input audio signal; and

calculating a second ratio of direct versus reflective strengths of the output audio in the second input audio signal.

17. A method comprising:

obtaining a first input audio signal representing audio received at a first device, wherein the first input audio signal represents output audio produced by a speaker of a second device;

cancelling the output audio from the first input audio signal based at least in part on a first set of filter parameters;

determining a measurement of the output audio in the first input audio signal based at least in part on the first set filter parameters;

determining that the measurement does not satisfy a criteria; and

providing a notification to increase a distance between the first device and the second device.

18. The method of claim 17, wherein the measurement comprises the distance between the first device and the second device and the criteria comprises one or more of a minimum distance and a maximum distance.

19. The method of claim 17, wherein determining the measurement comprises comparing direct versus reflective strengths of the output audio in the first input audio signal.

20. The method of claim 17, wherein the measurement comprises a strength of the output audio in the first input audio signal.

21. The method of claim 20, wherein determining the measurement comprises determining the strength of the output audio in the first input audio signal based at least in part on one or more of the first set of filter parameters corresponding to a direct acoustic path between the second device and the first device.

22. The method of claim 20, wherein determining the measurement comprises determining the strength of the output audio in the first input audio signal by comparing (a) one or more of the first set of filter parameters corresponding to a direct acoustic path between the second device and the first device;

and (b) one or more of the first set of filter parameters corresponding to one or more reflective acoustic paths between the second device and the first device.

23. The method of claim 17, further comprising:

obtaining a second input audio signal representing audio received at the second device;

cancelling the output audio from the second input audio signal based at least in part on a second set of filter parameters; and

wherein determining the measurement is performed as a function of the first and second sets of filter parameters.

24. The method of claim 23, wherein determining the measurement comprises:

determining a first strength of the output audio in the first input audio signal by analyzing the first set of filter parameters; and

determining a second strength of the output audio in the second input audio signal by analyzing the second set of filter parameters.