NOISE CHARACTERIZATION AND ATTENUATION USING LINEAR PREDICTIVE CODING

• US 20170272869A1
• Filed: 03/21/2016
• Published: 09/21/2017
• Est. Priority Date: 03/21/2016
• Status: Active Grant

• Current Assignee: Starkey Laboratories Incorporated
• Original Assignee: Starkey Laboratories Incorporated
• Inventors: Salvetti, Arthur, McKinney, Martin
• Granted Patent: US 10,251,002 B2
• Time in Patent Office: Days
• CPC Class Codes: G10L 21/0224 Processing in the time domain
• CPC Class Codes: G10L 21/0264 characterised by the type of parameter measurement, e.g. correlation techniques, zero crossing techniques or predictive techniques
• CPC Class Codes: G10L 25/12 the extracted parameters being prediction coefficients
• CPC Class Codes: G10L 25/84 for discriminating voice from noise
• CPC Class Codes: H04R 2225/023 Completely in the canal [CIC] hearing aids
• CPC Class Codes: H04R 2225/025 In the ear hearing aids [ITE] hearing aids
• CPC Class Codes: H04R 2225/43 Signal processing in hearing aids to enhance the speech intelligibility
• CPC Class Codes: H04R 25/505 using digital signal processing

Abstract

Disclosed herein, among other things, are apparatus and methods for noise characterization and attenuation for hearing assistance devices. In various embodiments, a method of operating a hearing assistance device includes receiving an audio signal using a microphone of the hearing assistance device and identifying a transient in the audio signal. Linear predictive coding (LPC) is used to isolate speech segments and non-speech segments of the transient and fluctuating noise, and the non-speech segments of the transient and fluctuating noise are attenuated to reduce annoyance of the noise and maintain audibility of perceptually important transients in speech.

Claims

1. A method of operating a hearing assistance device, the method comprising:

receiving an audio signal using a microphone of the hearing assistance device;

identifying and isolating a transient in the audio signal using a dynamic threshold calculation;

using linear predictive coding (LPC) to isolate speech segments and non-speech segments of the transient in the audio signal; and

attenuating the non-speech segments of the transient to reduce annoyance of noise and maintain audibility of perceptually important transients in speech.

2. The method of claim 1, wherein using LPC includes using an adaptive normalized least means squares (NLMS) filter.

3. The method of claim 1, comprising determining a prediction error magnitude.

4. The method of claim 3, comprising applying a linear finite impulse response (FIR) filter using past samples to predict a value of a current sample.

5. The method of claim 3, comprising computing an exponentially smoothed average based on the prediction error magnitude.

6. The method of claim 1, comprising performing a dynamic threshold calculation.

7. The method of claim 6, comprising making a detection decision based on the calculated dynamic threshold and a pre-set threshold value.

8. The method of claim 7, comprising setting attenuation gain value based on instantaneous values of prediction error magnitude, current gain, the pre-set threshold value, and the calculated dynamic threshold.

9. The method of claim 7, comprising making a detection decision based on the calculated dynamic threshold and multiple pre-set threshold values.

10. The method of claim 1, comprising using a sample-and-delay peak tracker for transient detection.

11. The method of claim 1, further comprising identifying the transient in the audio signal.

12. A hearing assistance device, comprising:

a microphone configured to receive audio signals; and

a processor configured to process the audio signals to correct for a hearing impairment of a wearer, the processor further configured to;

identify and isolate a transient in the audio signal using a dynamic threshold calculation;

use linear predictive coding (LPC) to isolate speech segments and non-speech segments of the transient in the audio signal; and

attenuate the non-speech segments of the transient to reduce annoyance of noise and maintain audibility of perceptually important transients in speech.

13. The hearing assistance device of claim 12, wherein the hearing assistance device is a hearing aid.

14. The hearing assistance device of claim 13, wherein the hearing aid is a behind-the-ear (BTE) hearing aid.

15. The hearing assistance device of claim 13, wherein the hearing aid is an in-the-ear (ITE) hearing aid.

16. The hearing assistance device of claim 13, wherein the hearing aid is an in-the-canal (ITC) hearing aid.

17. The hearing assistance device of claim 13, wherein the hearing aid is a completely-in-the-canal (CIC) hearing aid.

18. The hearing assistance device of claim 13, wherein the hearing aid is a receiver-in-canal (RIC) hearing aid.

19. The hearing assistance device of claim 13, wherein the hearing aid is a receiver-in-the-ear (RITE) hearing aid.

20. The hearing assistance device of claim 13, wherein the hearing aid is an invisible-in-canal (IIC) hearing aid.