Active noise-reduction earphones and noise-reduction control method and system for the same

Patent metadata

Field	Value
Publication number	US-10115387-B2
Application number	US-201715857903-A
Country	US
Kind code	B2
Filing date	Dec 29, 2017
Priority date	Dec 31, 2014
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A noise-reduction control method includes performing frequency-domain weighting and temporal-domain weighting to a noise signal collected at current time to obtain a weighted energy. Judging whether active noise-reduction control is needed based on the weighted energy; calculating an energy value of a first sub-band and an energy value of a second sub-band of the noise signal collected by the feedforward microphone at the current time, wherein the first sub-band and the second sub-band are determined based on a feedforward noise-reduction curve and a feedback noise-reduction curve of the earphone, respectively. Determining a feedforward noise-reduction amount and a feedback noise-reduction amount based on the energy value of the first sub-band and the energy value of the second sub-band, respectively. Controlling the earphone to perform feedforward noise reduction based on the feedforward noise-reduction amount, and controlling the earphone to perform feedback noise reduction based on the feedback noise-reduction amount.

First claim

What is claimed is:

1. A noise-reduction control method for active noise-reduction earphones, wherein providing a feedforward microphone on each earphone of the active noise-reduction earphones, respectively; the feedforward microphone being disposed outside of the earphone; the noise-reduction control method comprising:
performing frequency-domain weighting and temporal-domain weighting to a noise signal collected by the feedforward microphone at current time to obtain a weighted energy;
judging whether active noise-reduction control is needed at the current time based on the weighted energy;
when the active noise-reduction control is needed, calculating an energy value of a first sub-band and an energy value of a second sub-band of the noise signal collected by the feedforward microphone at the current time, wherein the first sub-band and the second sub-band are determined based on a feedforward noise-reduction curve and a feedback noise-reduction curve of the earphone, respectively;
determining a feedforward noise-reduction amount and a feedback noise-reduction amount based on the energy value of the first sub-band and the energy value of the second sub-band, respectively;
controlling the earphone to perform feedforward noise reduction based on the feedforward noise-reduction amount, and
controlling the earphone to perform feedback noise reduction based on the feedback noise-reduction amount,
wherein performing frequency-domain weighting to a noise signal collected by the feedforward microphone at current time according to the following formula:
v ( n )= R A ( f )* s 1

wherein, y(n) is a signal obtained after the frequency-domain weighting, s 1 is the noise signal, f is a frequency of the noise signal, and R A (f) is a frequency weighting coefficient,

R
A

⁡

(
f
)

=

12200
2

·

f
4

(

f
2

+

20.6
2

)

⁢

(

f
2

+

107.7
2

)

⁢

(

f
2

+

737.9
2

)

⁢

(

f
2

+

12200
2

)

.

2. The noise-reduction control method according to claim 1 , wherein performing temporal-domain weighting to a noise signal collected by the feedforward microphone at current time according to the following formula:
SPL ( n )=α*Energy( n )+(1−α)* SPL ( n− 1)

wherein, SPL(n) is a weighted energy of a current frame; α is a temporal weighting coefficient; Energy(n) is an energy value of a current frame, wherein Energy(n)=y 2 (n); and SPL(n−1) is a weighted energy of a last frame.

3. The noise-reduction control method according to claim 1 , wherein passing the noise signal collected by the feedforward microphone at current time through a bandpass filter, and calculating an energy value of a first sub-band and an energy value of a second sub-band of the noise signal collected by the feedforward microphone at current time according to the following formula:
Energy=Σ y 2 ( n ), y ( n )= s 1* h ( n ),

wherein, Energy is the energy value of the first sub-band or the energy value of the second sub-band; and y(n) denotes the sub-band signal obtained after the noise signal s 1 passes through the bandpass filter h(n), and n denotes time.

4. The noise-reduction control method according to claim 1 , wherein transforming the noise signal collected by the feedforward microphone at current time to frequency domain by Fast Fourier Transformation, and calculating an energy value of a first sub-band and an energy value of a second sub-band of the noise signal collected by the feedforward microphone at current time according to the following formula:

Engery
=

∑

subband
⁢

⁢
1

subband
⁢

⁢
2

⁢

⁢

α
·
S

⁢

⁢

1
2

⁢

(
k
)

wherein, Energy is the energy value of the first sub-band or the energy value of the second sub-band; (subband 1 , subband 2 ) is a frequency-domain range of the first sub-band or a frequency-domain range of the second sub-band; α is a weight coefficient; and S 1 ( k )=FFT(s 1 ), S 1 ( k ) denotes a signal obtained after the noise signal s 1 transforms by Fast Fourier Transformation.

5. The noise-reduction control method according to claim 1 , wherein providing a feedback microphone on each earphone of the active noise-reduction earphones, respectively, the feedback microphone being provided within a coupled cavity coupling the earphone with a human ear, the no

Assignees

• Goertek Inc

Inventors

• Liu Song
• Wang Linzhang
• Li Bo

Classifications

• G10K2210/3026

  Feedback · CPC title

• G10K2210/3027

  Feedforward · CPC title

• G10K11/17815 Primary

  between the reference signals and the error signals, i.e. primary path · CPC title

• G10K2210/1081

  Earphones, e.g. for telephones, ear protectors or headsets · CPC title

• H04R1/1008

  Earpieces of the supra-aural or circum-aural type · CPC title