Speech enhancing method, device for communication earphone and noise reducing communication earphone

• US 9,484,042 B2
• Filed: 03/16/2012
• Issued: 11/01/2016
• Est. Priority Date: 08/10/2011
• Status: Active Grant

• Current Assignee: Goertek Incorporated
• Original Assignee: Goertek Incorporated
• Inventors: Liu, Song, Li, Bo, Zhao, Jian
• Primary Examiner(s): He, Jialong
• Application Number:
  US14/110,879
• Publication Number:
  US 20140172421A1
• Time in Patent Office: 1,691 Days
• US Class Current: 1/1
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H04R 1/1041 Mechanical or electronic switches, or control elements switches in general H01H
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 2410/01 Noise reduction using microphones having different directional characteristics
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

The present invention provides a speech enhancing method for communication earphone including two parts: sending end noise reduction processing and receiving end noise reduction processing, wherein the sending end noise reduction processing part includes: determining a wearing condition of the earphone by comparing energy difference of sound signals picked up by microphones of the communication earphone; if the earphone is normally worn, subjecting the sound signal first to multi-microphone noise reduction and then to single channel noise reduction to further suppress residuary stationary noise; otherwise suppressing stationary noise in the sound signal by single channel noise reduction directly.

Claims

1. A speech enhancing method for a communication earphone, said communication earphone comprising a sending end comprising at least two microphones;

and a receiving end comprising at least one microphone and a speaker, wherein said speech enhancing method comprises;

implementing noise reduction at both said sending end and said receiving end of said communication earphone respectively by multiplexing sound signals picked up by the microphones of the said sending end, wherein the noise reduction processing at said sending end comprises;

determining a wearing condition of said communication earphone by determining an energy difference among the sound signals picked up by the at least two microphones of said sending end;

if said energy difference is greater than a first preset threshold, determining that said communication earphone is normally worn, said sound signals being first processed by multi-microphone noise reduction processing and then processed by single channel noise reduction processing to further suppress residuary stationary noise; and

if said energy difference is smaller than or equal to the first preset threshold, determining that said communication earphone is abnormally worn and suppressing stationary noise in said sound signals directly by the single channel noise reduction.

2. The speech enhancing method for the communication earphone according to claim 1, wherein multi-microphone noise reduction processing comprises:

distinguishing speech signal components and noise signal components in said sound signals by comparing the energy difference among frequency components in said sound signals; and

subjecting said noise signal components to attenuation processing.

3. The speech enhancing method for the communication earphone according to claim 2, wherein in the process of distinguishing the speech signal components and the noise signal components in said sound signals by comparing the energy difference among frequency components in said sound signals,

if the energy difference of a certain frequency component in said sound signals is greater than a second preset threshold, the frequency component of which the energy difference is greater than said second preset threshold is determined as a speech signal component;

and

if the energy difference of a certain frequency component in said sound signals is less than or equal to said second preset threshold, the frequency component of which the energy difference is less than or equal to said second preset threshold is determined as a noise signal component.

4. The speech enhancing method for the communication earphone according to claim 1, wherein the process of suppressing stationary noise by single channel noise reduction comprises:

calculating energies of noises of various frequencies in said sound signals by a smooth-average method; and

removing the energies of noises in said sound signals.

5. The speech enhancing method for the communication earphone according to claim 1, wherein an in-ear part of said communication earphone has a non-closed earplug structure, and a position where the speaker of said communication earphone is coupled with an ear canal is relatively constant under normal wearing condition;

and the noise reduction processing at said receiving end comprises;

utilizing the microphones constituting the receiving end to pick up a noise signal;

obtaining an antinoise signal according to said noise signal; and

mixing the antinoise signal with a speech signal received by the receiving end and feeding the antinoise signal and the speech signal into ears via the speaker constituting the receiving end.

6. The speech enhancing method for the communication earphone according to claim 5, wherein the obtaining the antinoise signal according to said noise signal, comprises:

inverting said noise signal by an inverter to obtain a primary antinoise signal; and

modifying and adjusting a phase of said primary antinoise signal in audio frequency range utilizing a phase compensator, to obtain an antinoise signal with a phase exactly opposite to that of said noise signal, wherein said phase compensator comprises an active filter implemented by a twin T network to compensate for phase loss at low frequency part caused by the non-closed earplug structure.

7. The speech enhancing method for communication earphone according to claim 1, further comprising a process of detecting and suppressing howling, wherein the process comprises:

if an energy of a certain frequency of a frequency spectrum of the sound signals picked up by the microphones of said communication earphone is higher than that of other frequency bands by a preset value or more and the energy of the certain frequency is still increasing, then autonomously adjusting the noise reduction at said receiving end.

8. A communication earphone comprising:

a sending end comprising at least two microphones;

a receiving end comprising at least one microphone and a speaker;

a sending end noise reduction unit; and

a receiving end noise reduction unit,

wherein said sending end noise reduction unit comprises;

a wearing condition determining module configured to determine a wearing condition of said communication earphone by comparing an energy difference of sound signals picked up by the at least two microphones of said sending end, and wherein, if said energy difference is greater than a first preset threshold, the wearing condition determining module is configured to determine that said communication earphone is normally worn, and if the energy difference is smaller than or equal to the first preset threshold, the wearing condition determining module is configured to determine that said communication earphone is abnormally worn;

a multi-microphone noise reduction module configured to subject said sound signals to multi-microphone noise reduction processing when said communication earphone is normally worn; and

a single channel noise reduction module configured to, if said communication earphone is normally worn, further suppress residuary stationary noise after said multi-microphone noise reduction module has subjected said sound signals to noise reduction processing, and configured to, if said communication earphone is abnormally worn, subject steady state noise in said sound signals to suppressing processing.

9. The communication earphone according to claim 8, wherein said multi-microphone noise reduction module further comprises:

a sound signal component distinguishing module configured to distinguish speech signal components and noise signal components in said sound signals by comparing energy difference among frequency components in said sound signals; and

a noise signal attenuating module configured to subject said noise signal components to attenuation processing.

10. The communication earphone according to claim 8, wherein said single channel noise reduction module further comprises:

a noise energy calculating module configured to calculate noise energies of various frequencies in said sound signals by a smooth-average method; and

a noise energy removing module configured to remove said noise energy in said sound signals.

11. The communication earphone according to claim 8, wherein an in-ear part of said communication earphone has a non-closed earplug structure, and a position where the speaker of said communication earphone is coupled with an ear canal is relatively constant under normal wearing condition;

and said receiving end noise reduction unit comprises;

a noise signal picking up module configured to pick up a noise signal utilizing the microphones of said receiving end;

an antinoise signal determining module configured to obtain an antinoise signal according to said noise signal; and

an output signal mixing module configured to superimpose said antinoise signal and a speech signal received by the receiving end and feed said antinoise signal and said speech signal into ears via the speaker of said receiving end.

12. The communication earphone according to claim 11, wherein said antinoise signal determining module further comprises:

an inverter configured to invert said noise signal and obtain a primary antinoise signal; and

a phase compensator configured to modify and adjust a phase of the primary antinoise signal in audio frequency range, in order to obtain an antinoise signal with the phase exactly opposite to that of said noise signal and apply an active filter implemented by a twin T network to compensate for phase loss at low frequency part caused by the non-closed earplug structure.

13. The communication earphone according to claim 8, wherein said communication earphone further comprises:

a howling detection unit configured to autonomously adjust the noise reduction at said receiving end by a control signal, if an energy of a certain frequency of a frequency spectrum of the sound signals picked up by microphones of said communication earphone is higher than that of other frequency bands by a preset value or more and the energy of the certain frequency is still increasing.

14. A communication earphone comprising:

at least two sending end microphones;

at least one receiving end microphone;

at least one speaker;

a sending end noise reduction unit connected with one or more of the at least two sending end microphones and one or more of the at least one receiving end microphone;

wherein said sending end noise reduction unit comprises;

a wearing condition determining module configured to determine a wearing condition of said communication earphone by comparing an energy difference of sound signals picked up by the at least two sending end microphones, and wherein, if said energy difference is greater than a first preset threshold, the wearing condition determining module is configured to determine that said communication earphone is normally worn, and if the energy difference is smaller than or equal to the first preset threshold, the wearing condition determining module is configured to determine that said communication earphone is abnormally worn;

a multi-microphone noise reduction module configured to subject said sound signals to multi-microphone noise reduction processing when said communication earphone is normally worn; and

a single channel noise reduction module configured to, if said communication earphone is normally worn, further suppress residuary stationary noise after said multi-microphone noise reduction module has subjected said sound signals to noise reduction processing, and configured to, if said communication earphone is abnormally worn, subject steady state noise in said sound signals to suppressing processing; and

a receiving end noise reduction unit connected with one or more of the at least one receiving end microphone, the receiving end noise reduction unit connected with the at least one speaker,

wherein the receiving end noise reduction unit comprises;

a noise signal picking up module configured to pick up a noise signal utilizing the microphones of said receiving end;

an antinoise signal determining module configured to obtain an antinoise signal according to said noise signal; and

an output signal mixing module configured to superimpose said antinoise signal and a speech signal received by the receiving end and transmit said antinoise signal and said speech signal via the speaker of said receiving end.

15. The communication earphone according to claim 14, wherein, during operation of the communication earphone, said antinoise signal and said noise signal are canceled out with each other while said speech signal remains unchanged.

16. The communication earphone according to claim 14, further comprising:

an inverter connected with one or more of the at least one receiving end microphone, wherein the inverter is configured to invert said noise signal and obtain a primary antinoise signal; and

a phase compensator connected with one or more of the at least one receiving end microphone, wherein the phase comparator is configured to modify and adjust a phase of the primary antinoise signal in an audio frequency range, in order to obtain said antinoise signal with a phase exactly opposite said noise signal and to apply an active filter implemented by a twin T network to compensate for phase loss at low frequency part caused by a non-closed earplug structure.

17. The communication earphone according to claim 14, further comprising:

a first amplifier connected with one or more of the at least one receiving end microphone, wherein the first amplifier is configured to amplify said noise signal picked up by the noise picking up module; and

a second amplifier connected with one or more of the at least one receiving end microphone and the at least one speaker, the second amplifier is configured to amplify a mixed signal resulted from superimposing said antinoise signal and said speech signal.

18. The communication earphone according to claim 17, wherein said noise signal picked up by the receiving end microphone is amplified by the first amplifier, and then processed by an inverter and the phase compensator to generate the antinoise signal with identical amplitude and opposite phase with respect to said noise signal.