SPEECH ENHANCING METHOD, DEVICE FOR COMMUNICATION EARPHONE AND NOISE REDUCING COMMUNICATION EARPHONE

• US 20140172421A1
• Filed: 03/16/2012
• Published: 06/19/2014
• Est. Priority Date: 08/10/2011
• Status: Active Grant

• Current Assignee: Goertek Incorporated
• Original Assignee: Goertek Incorporated
• Inventors: Liu, Song, Li, Bo, Zhao, Jian
• Granted Patent: US 9,484,042 B2
• Time in Patent Office: Days
• US Class Current: 704/227
• 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 consisting of at least two microphones and a receiving end consisting of at least one microphone and one speaker, said method implementing noise reduction at both the sending end and the receiving end of said communication earphone respectively by multiplexing a plurality of microphones'"'"' signals, wherein the noise reduction processing at said sending end comprises:

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

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

otherwise,

determining that said communication earphone is abnormally worn and suppressing stationary noise in said sound signal directly by single channel noise reduction.

2. The speech enhancing method for a communication earphone according to claim 1, wherein the process of subjecting said sound signal to multi-microphone noise reduction specifically comprises:

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

subjecting said noise signal components to attenuation processing.

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

if the energy difference of a certain frequency component in said sound signal 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;

if the energy difference of a certain frequency component in said sound signal 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 a communication earphone according to claim 1, wherein the process of suppressing stationary noise by single channel noise reduction specifically comprises:

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

removing said energies of noises in said sound signal.

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

and the noise reduction processing at said receiving end comprises;

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

obtaining an antinoise signal according to said noise signal;

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

6. The speech enhancing method for a communication earphone according to claim 5, wherein in the process of obtaining the antinoise signal according to said noise signal,

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

then modifying and adjusting the 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 structure.

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

if the energy of a certain frequency of the frequency spectrum of the sound signal 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 said frequency is still increasing, then autonomously adjusting the noise reduction at said receiving end.

8. A communication earphone comprising a sending end consisting of at least two microphones and a receiving end consisting of at least one microphone and one speaker as well as 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 microphones constituting said sending end, and if said energy difference is greater than a first preset threshold, then determining that said communication earphone is normally worn, otherwise determining that said communication earphone is abnormally worn;

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

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

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 signal by comparing energy difference among frequency components in said sound signal;

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 signal by a smooth-average method;

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

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 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 microphones constituting said receiving end;

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

an output signal mixing module configured to superimposing said antinoise signal and said speech signal received by the receiving end and feeding it into ears via the speaker constituting the 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;

a phase compensator configured to modify and adjust the phase of the primary antinoise signal in audio frequency range, in order to obtain an antinoise signal with a 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 structure.

13. The communication earphone according to claim 8, 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 the energy of a certain frequency of a frequency spectrum of the sound signal 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 said frequency is still increasing.