METHOD AND APPARATUS FOR AUDIO INTERFERENCE ESTIMATION

• US 20150271616A1
• Filed: 10/04/2013
• Published: 09/24/2015
• Est. Priority Date: 10/09/2012
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Kechichian, Patrick
• Granted Patent: US 9,591,422 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04R 2227/007 Electronic adaptation of audio signals to reverberation of the listening space for PA
• CPC Class Codes: H04R 2227/009 Signal processing in [PA] systems to enhance the speech intelligibility
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 29/004 for microphones H04R29/007 takes precedence
• CPC Class Codes: H04R 3/002 Damping circuit arrangements for transducers, e.g. motional feedback circuits
• CPC Class Codes: H04R 3/02 for preventing acoustic reaction , i.e. acoustic oscillatory feedback specially adapted for hearing aids H04R25/453
• CPC Class Codes: H04R 3/04 for correcting frequency response

Abstract

An apparatus comprises a receiver (203) which receives a microphone signal from a microphone (201) where the microphone signal comprises a test signal component corresponding to an audio test signal. A divider (215) divides the microphone signal into a plurality of test interval signal components, each of which corresponds to the microphone signal in a time interval. A set processor (217) generates sets of test interval signal components and a similarity processor (219) generates a similarity value for each set. An interference estimator (221) determines an interference measure for individual test interval signal components in response to the similarity values. The interference measure may be used to select signal segments that can be used to adapt an audio processing algorithm which is applied to the microphone signal, such as e.g. speech enhancement or echo cancellation. The approach may allow for a reliable interference estimate to be generated while maintaining low complexity.

Claims

1. An apparatus comprising:

a receiver for receiving a microphone signal from a microphone, the microphone signal comprising a test signal component corresponding to an audio test signal captured by the microphone;

a divider for dividing the microphone signal into a plurality of test interval signal components, each test interval signal component corresponding to the microphone signal in a time interval, wherein the audio test signal comprises a plurality of repetitions of an audio signal component, and a timing of the test interval signal components corresponds to a timing of the repetitions;

a set processor for generating sets of test interval signal components from the plurality of test interval signal components;

a similarity processor for generating a similarity value for each set of test interval signal components;

an interference estimator for determining an interference measure for individual test interval signal components in response to the similarity values.

2. The apparatus of claim 1 further comprising a calibration unit for adapting a signal processing in response to the test interval signal components, the adaptation unit being arranged to weigh at least a first test interval signal component contribution in response an interference estimate for the first time interval.

3. The apparatus of claim 2 wherein the calibration unit is arranged to discard test interval signal components for which the interference estimate is above a threshold.

4. The apparatus of claim 1 further comprising a stationary noise estimator arranged to generate a stationary noise estimate and to compensate at least one of the threshold and the interference estimate in response to the stationary noise estimate.

5. The apparatus of claim 4 wherein the stationary noise estimate is a noise floor estimate.

6. The apparatus of claim 1 further comprising a test signal estimator arranged to generate a level estimate for the test signal component and to compensate at least one of the threshold and the interference estimate in response to the level estimate.

7. The apparatus of claim 1 wherein the divider is arranged to divide the microphone signal into the plurality of test interval signal components in response to repetition characteristics of the audio test signal.

9. The apparatus of claim 1 wherein the interference estimator is arranged to, for a first test interval signal component of the plurality of test interval signal components, determine a maximum similarity value for similarity values of sets including the first test interval signal component;

and to determine the interference measure for the first test interval signal component in response to the maximum similarity value.

10. The apparatus of claim 1 wherein the divider is arranged to generate at least two sets comprising at least a first of the test interval signal components.

11. The apparatus of claim 1 wherein each set consists of two test interval signal components.

12. The apparatus of claim 11 wherein the divider is arranged to generate sets corresponding to all pair combinations of the test interval signal components.

13. The apparatus of claim 10 wherein each test interval signal component has a duration of no less than 10 msec and no more than 200 msec.

8. (canceled)

14. A method of generating an audio interference measure, the method comprising:

receiving a microphone signal from a microphone, the microphone signal comprising a test signal component corresponding to an audio test signal captured by the microphone;

dividing the microphone signal into a plurality of test interval signal components, each test interval signal component corresponding to the microphone signal in a time interval, wherein the audio test signal comprises a plurality of repetitions of an audio signal component, and a timing of the test interval signal components corresponds to a timing of the repetitions;

generating sets of test interval signal components from the plurality of test interval signal components;

generating a similarity value for each set of test interval signal components; and

determining an interference measure for individual test interval signal components in response to the similarity values.

15. A computer program product comprising computer program code means adapted to perform all the steps of claim 14 when said program is run on a computer.