Granted Patent B2

US 12,592,244 · App. 17/912,912 · Granted Mar 31, 2026

Inventors: Wenyu Jin (Eden Prairie, MN); Tao Zhang (Eden Prairie, MN)

Assignee: Starkey Laboratories, Inc.

G10L21/0232H04R1/1083H04R3/04

Abstract

Claims (43)

1 . A method comprising:

receiving a digitized signal that includes speech;

applying a low-pass filter at a cut-off frequency to the digitized signal to remove a high-frequency component and obtain a low-frequency component;

applying speech enhancement to the low-frequency component;

applying blind bandwidth extension to the enhanced low-frequency component to obtain a bandwidth-extended high frequency component that is an estimate of the high frequency component;

outputting, to a loudspeaker of an ear-wearable device, an enhanced speech signal that is a combination of the enhanced low-frequency component and the bandwidth-extended high frequency component; and

updating the cutoff frequency of the low-pass filter during use of the ear-wearable device based on iteratively updating an average of the signal quality estimates for frequency bands below the cutoff frequency with signal quality estimates of additional sub-bands greater than the cutoff frequency until the updated average is less than the threshold, the updated cutoff frequency being based on a highest frequency sub-band of the additional sub-bands.

2 . The method of claim 1 , further comprising performing linear predictive coding (LPC) on the digitized signal after the low-pass filter is applied, an analysis filter of the LPC being used for predicting an enhanced low-frequency excitation signal which is used as input to excitation signal extension, wherein coefficients of the LPC are used to extend a spectral envelope of an output of the excitation signal extension, wherein a subset of the LPC coefficients are selected for spectral envelope extension based on a level of hearing loss of a user of the ear-wearable electronic device.

3 . The method of claim 1 , wherein the speech enhancement is performed in a frequency domain, and the blind bandwidth extension is performed in a time domain.

4 . The method of claim 1 , wherein the removal of the high frequency component reduces a complexity of the speech enhancement.

5 . The method of claim 1 , wherein the signal quality estimates comprise at least one of a posteriori signal-to-noise-ratio (SNR) and a coherent-to-diffuse power ratio (CDR).

6 . The method of claim 1 , wherein the cutoff frequency is updated if the average of the signal quality estimates for frequency bands below the cutoff frequency is greater than a threshold.

7 . The method of claim 1 , wherein the cutoff frequency of the low-pass filter is updated during use of the ear-wearable device based on a change in coherent to diffuse ratio of the digitized speech.

8 . The method of claim 1 , wherein the cutoff frequency of the low-pass filter is updated during use of the ear-wearable device based on a combination of:

a change in posteriori signal-to-noise-ratio (SNR) estimates for frequency bands below the cutoff frequency; and

a change in coherent to diffuse ratio (CDR) of the digitized speech.

9 . The method of claim 1 , wherein applying the speech enhancement to the low-frequency component comprises speech detection via a neural network.

10 . An ear-wearable electronic device, comprising:

at least one microphone configured to convert sound that includes speech to an electrical signal;

a loudspeaker;

an analog to digital converter that converts the electrical signal to a digitized signal; and

a processor operably coupled to the microphone, the loudspeaker, and the analog to digital converter, the processor operable to:

apply a low-pass filter at a cut-off frequency to the digitized signal to remove a high-frequency component and obtain a low-frequency component;

applying speech enhancement to the low-frequency component;

applying blind bandwidth extension to the enhanced low-frequency component to recover or synthesize an estimate of at least part of the high frequency component; and

output an enhanced speech signal via the loudspeaker that is a combination of the enhanced low-frequency component and the bandwidth-extended high frequency component; and

update the cutoff frequency of the low-pass filter during use of the ear-wearable device based on iteratively updating an average of the signal quality estimates for frequency bands below the cutoff frequency with signal quality estimates of additional sub-bands greater than the cutoff frequency until the updated average is less than a threshold, the updated value of the cutoff frequency being based on a highest frequency sub-band of the additional sub-bands.

11 . The ear-wearable electronic device of claim 10 , wherein the processor is further configured to perform linear predictive coding (LPC) on the digitized signal after the low-pass filter is applied, an analysis filter of the LPC being used for predicting an enhanced low-frequency excitation signal which is used as input to excitation signal extension, wherein coefficients of the LPC are used to extend a spectral envelope of an output of the excitation signal extension, wherein a subset of the LPC coefficients are selected for spectral envelope extension based on a level of hearing loss of a user of the ear-wearable electronic device.

12 . The ear-wearable electronic device of claim 10 , wherein the speech enhancement is performed in a frequency domain, and the blind bandwidth extension is performed in a time domain.

13 . The ear-wearable electronic device of claim 10 , wherein the signal quality estimates comprise at least one of a posteriori signal-to-noise-ratio (SNR) and a coherent-to-diffuse power ratio (CDR).

14 . The ear-wearable electronic device of claim 13 , wherein the cutoff frequency is updated if the average of the signal quality estimates for frequency bands below the cutoff frequency is greater than a threshold.

15 . The ear-wearable electronic device of claim 10 , wherein the cutoff frequency of the low-pass filter is updated during use of the ear-wearable device based on a change in coherent to diffuse ratio of the digitized speech.

16 . The ear-wearable electronic device of claim 10 , wherein the cutoff frequency of the low-pass filter is updated during use of the ear-wearable device based on a combination of:

a change in posteriori signal-to-noise-ratio (SNR) estimates for frequency bands below the cutoff frequency; and

a change in coherent to diffuse ratio (CDR) of the digitized speech.

17 . An ear-wearable electronic device, comprising:

at least one microphone configured to convert sound that includes speech to an electrical signal;

a low-pass filter that obtains a low-frequency component from the electrical signal;

a speech enhancement processor that uses machine-learning to produce a narrowband enhanced excitation signal from the low-frequency component;

an excitation extension module that frequency-extends the enhanced narrowband excitation signal to a wideband enhanced excitation signal;

a linear predictive coder (LPC) that produces a spectral envelope extension from the low-frequency component; and

a loudspeaker that converts an enhanced speech signal into audio, the enhanced speech signal comprising a convolution of the wideband enhanced excitation signal and the spectral envelope extension, wherein a cutoff frequency of the low-pass filter is updated during use of the ear-wearable device based on iteratively updating an average of the signal quality estimates for frequency bands below the cutoff frequency with signal quality estimates of additional sub-bands greater than the cutoff frequency until the updated average is less than the threshold, the updated cutoff frequency being based on a highest frequency sub-band of the additional sub-bands, wherein the signal quality estimates comprise at least one of a posteriori signal-to-noise-ratio (SNR) and a coherent-to-diffuse power ratio (CDR).

18 . The ear-wearable electronic device of claim 17 , wherein the excitation extension module frequency-extends the enhanced narrowband excitation signal to recover or synthesize a high frequency range.

Continuity (2)

References Cited (24)