KR101905420B1 - Noise reduction device and method - Google Patents

Abstract

The present invention relates to a noise reduction apparatus and method, and more particularly, to a noise reduction apparatus and a noise reduction method. The noise reduction apparatus includes a modulator 20 for converting a signal of a microphone 10, which detects external noise, into a digital signal, And a frequency dispersion processing unit (32) for attenuating the intensity of the frequency signal and outputting white noise by increasing the frequency energy of the band adjacent to the attenuated frequency signal, and a filter unit And a demodulator 40 for converting the output signal of the demodulator 40 into an analog signal and outputting the analog signal through the speaker 50. The present invention can reduce external noise to white noise so that the wearer can hear the noise, so that the wearer can hear the surrounding voice or warning sound, It is possible to prevent the occurrence of the trouble, and to communicate smoothly during the work.

Description

[0001] The present invention relates to a noise reduction device and method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise reduction apparatus and method, and more particularly, to a noise reduction apparatus and method for reducing noise through inversion frequency and frequency dispersion for noise.

In general, workers working in a high noise area such as industrial sites have a high probability of hearing loss, and measures are needed to reduce the noise that damages people. As a method for eliminating such noise, there are a passive noise removing method using a sound absorbing material and the like and an active method of reducing noise by generating a sound wave canceling the noise.

Techniques known as the active methods detect noise and generate sound waves having a phase opposite to that of the noise, thereby canceling the noise.

An example of such an active noise reduction device is disclosed in Japanese Patent Laid-Open No. 10-2002-0073907 (September 29, 2002, Noise Cancellation Device).

In the above-described Patent Document No. 10-2002-0073907, a noise is detected in a noise source, and after converting it electrically, a phase reversal sound is generated through a phase reversal sound generating means and mixed with the above detected noise to generate a noise And a technique of canceling the above-mentioned conditions.

In addition, the noise is actively attenuated through the phase inversion described above, and the amplitude of the residual wave after the attenuation is calculated, and the amplitude of the after-reflected wave is again calculated And generates a disturbing sound to the user. This is to add a phase-reversed waveform repeatedly for noise and aftertone.

As such, conventional active noise reduction devices all generate a signal having a phase opposite to that of the noise, thereby attenuating the noise by adding the noise to the noise. In such a case, not only the noise but also the alarms There is a problem that communication can not be made smoothly in the industrial field.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a noise reduction apparatus and a noise reduction method which can reduce noise to a comfortable level without completely removing the noise.

Another object of the present invention is to provide a noise reduction apparatus and method that enables a user to easily turn on and off, thereby quickly responding to a surrounding situation.

In order to solve the above problems, the noise reduction apparatus of the present invention includes a modulation unit 20 for converting a signal of a microphone 10, which detects external noises, into a digital signal, And a frequency dispersion processing unit (32) for attenuating the intensity of the frequency signal higher than the set intensity and outputting white noise by increasing the frequency energy of the band adjacent to the attenuated frequency signal, And a demodulator 40 for converting an output signal of the demodulator 30 into an analog signal and outputting the demodulated signal through a speaker 50.

The filter unit 30 includes a phase inverting and mixing unit 31 for receiving a digital signal of the modulating unit 20 and generating a signal whose phase is inverted and mixing the digital signal with the digital signal of the modulating unit 20 And a mixer 33 for mixing the output signal of the phase inverting and mixing unit 31 and the signal of the frequency dispersion processing unit 32 and outputting the mixed signal.

The filter unit 30 operates under the control of the control unit 60 to select the output signals of the phase inversion and mixing unit 31 or the frequency dispersion processing unit 32 or the mixing unit 33, To the demodulation unit (40).

And a motion sensor 80 for detecting movement of the wearer so as to supply or cut off power from the control unit 60 or control the switch unit according to a signal detected by the motion sensor 80, It is possible to select the output signal of the mixing section 31 or the frequency dispersion processing section 32 or the mixing section 33. [

And a display unit 90 for displaying the remaining amount of power according to the control of the controller 60.

The microphone 10, the modulator 20, the filter 30, the demodulator 40 and the speaker 50 are accommodated in one case, and the case is partially inserted into the ear canal And the other part is a cannular structure located outside of the ear canal, and the portion that is drawn into the ear canal can be made of a material that can easily shield sound.

The noise reduction method of the present invention may further include the steps of: a) converting external noise into a digital noise signal; b) attenuating the intensity of the frequency signal higher than the preset intensity in the digital noise signal, Converting the white noise into an analog signal, and outputting the converted analog signal; and c) converting the white noise into an analog signal and outputting the analog signal.

B-1) receiving the digital noise signal at the same time as the step b), generating a signal whose phase is inverted from the digital noise signal, and mixing the canceled signal and the digital noise signal to cancel the signal; As shown in FIG.

And b-2) generating the white noise by mixing the resultant signal of the step b-1) with the resultant signal of the step b).

And may selectively output the result signal of step b) or the result signal of step b-1) or the result signal of step b-2, if necessary.

B) the result signal of step b), or the result signal of step b-1) or the result signal of step b-2) according to the movement of the wearer, And a mode for selectively outputting the result signal can be determined.

The noise reduction apparatus and method according to the present invention can reduce the noise of the wearer to a comfortable listening level by converting the detected analog noise signal into a digital signal, attenuating the digital noise signal, and dispersing the frequency band. Therefore, the wearer can hear the surrounding voice or warning sound, thereby preventing the occurrence of safety accidents and enabling smooth communication during work.

Further, the present invention can detect the motion of the wearer and turn it on or off, thereby improving the ease of use, and also making it possible to easily cope with noise or an unexpected situation around the wearer.

1 is a configuration diagram of a noise reduction apparatus according to a preferred embodiment of the present invention.
2 is a flowchart of a noise reduction method according to a preferred embodiment of the present invention.
FIG. 3 is a waveform diagram showing that white noise is generated by the processing of the frequency dispersion processing unit in FIG. 1; FIG.
4 is a configuration diagram of a noise reduction apparatus according to another embodiment of the present invention.

The noise reduction apparatus and method according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a noise reduction apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 1, a noise reduction apparatus according to a preferred embodiment of the present invention includes a microphone 10 for detecting an external noise and outputting an analog noise signal, and a microphone 10 for converting an analog noise signal of the microphone 10 into a digital noise signal A filter unit 30 for canceling the digital noise signal of the modulator 20 with a phase-inverted signal, attenuating a frequency magnitude, and performing dispersion processing to generate a white noise signal; A demodulating unit 40 for converting the white noise signal of the filter unit 30 into an analog signal, a speaker 50 for outputting the analog white noise signal of the demodulating unit 40 as white noise, And a power supply unit 70 for supplying power to the respective units.

Hereinafter, the configuration and operation of the noise reduction apparatus according to the preferred embodiment of the present invention will be described in detail. A flow chart of the noise reduction method according to the preferred embodiment of the present invention shown in FIG. 2 will be referred to Explain.

First, the microphone 10, the modulation unit 20, the filter unit 30, the demodulation unit 40, the control unit 60, and the power supply unit 70 are mounted in the same case, such as a canal type earphone, some of which protrude outside the ear canal and some of which are inserted into the ear canal.

Particularly, the portion inserted into the ear canal is preferably made of a material such as sponge or silicone having a high car sound, and it is preferable to prevent external noise from being directly transmitted to the wearer.

A microphone (10) is built in a portion of the case located outside the ear canal so that noise generated from the outside can be easily detected. As shown in step S10 of FIG. 2, the microphone 10 outputs an analog noise signal, which is an analog current signal, while vibrating according to external noise.

Then, in step S20, the modulator 20 receiving the analog noise signal converts the analog noise signal into a digital signal and outputs a digital noise signal. The reason for converting an analog signal to a digital signal is to facilitate signal processing in the filter 30 to be described later.

Then, in step S30, the filter 30 processes the digital noise signal to convert it into a white noise signal. The white noise is also referred to as white noise. Since the energy of sound or vibration has a waveform showing a constant spectrum regardless of the frequency or frequency, there is no frequency in which the intensity is relatively large, It is a noise that can be heard.

The filter (30) includes a phase inversion and mixing unit (31) for receiving the digital noise signal to generate a phase-inverted signal to cancel external noise, and a phase inverting and mixing unit (31) for receiving the digital noise signal to attenuate the intensity, And a mixer 33 for mixing the output signals of the phase inverting and mixing unit 31 and the output signals of the frequency dispersion processing unit 32 .

2, the phase inversion and mixing unit 31 receives the digital noise signal of the modulation unit 20, generates a digital signal having a phase-inverted phase, and mixes the digital noise signal with the inputted digital noise signal to generate a noise Offset.

In step S32, the frequency dispersion processing unit 32 receives the digital noise signal of the modulator 20 and attenuates the frequency by applying a decay constant to a frequency whose intensity (amplitude) is equal to or higher than the preset intensity, Increases the frequency energy of the adjacent frequency band of the frequency to output white noise.

FIG. 3 is a waveform chart showing that white noise is generated by the processing of the frequency dispersion processing unit 32. The frequency of the attenuated frequency is determined by attenuating frequencies having a set intensity or more at a predetermined ratio, Frequency energy is added so as to be a frequency signal having a strength lower than the intensity to generate a signal close to white noise.

Then, the output signal of the phase inverting and mixing unit 31 and the output signal of the frequency dispersion processing unit 32 are mixed and output using the mixing unit 33 as in step S33. The reason why the output signal of the phase inversion and mixing unit 31 and the output signal of the frequency dispersion processing unit 32 are mixed at this time is that even though a material excellent in sound insulation is applied to the case, And to be able to listen to the white noise in a state in which external noise is attenuated by using an inversion signal.

As described above, the present invention can generate a phase-inverted signal to cancel the noise, mix the white noise with the frequency dispersion, and output the result to the demodulation unit 40. The control unit 60 may further include a switch unit that is operated under the control of the control unit 60 so that only the signal of the phase inversion and mixing unit 31 canceling the noise using the phase inverted signal is output to the demodulation unit 40 Alternatively, only the output signal of the frequency dispersion processing unit 32 may be output to the demodulation unit 40.

This allows the wearer to determine the degree of blocking of the noise, thereby enabling the wearer to switch to an operating state suitable for the situation.

Then, as shown in step S40, the demodulation unit 40 converts the output signal of the filter unit 30 into an analog signal, and outputs the analog signal through the speaker 50. The speaker 50 is located at a portion of the case described above that is inserted into the inside of the ear canal to transmit white noise to the wearer.

Therefore, it is possible to listen to the voice and the warning sound of other people around, while reducing the noise around the whole.

4 is a configuration diagram of a noise reduction apparatus according to another embodiment of the present invention.

Referring to FIG. 4, the noise reduction apparatus according to another embodiment of the present invention includes the motion sensor 80 and the display unit 90 in addition to the example described above with reference to FIG.

The display unit 90 may display a remaining battery level or a current operation mode, and the motion sensor 80 may enable the wearer to easily turn on or off the present invention or to change the operation mode.

That is, when the wearer tilts his / her head once in the wearing direction while wearing the present invention, the control unit 60 supplies power to each part by the motion sensor 80 that senses such motion, The control unit 60 controls the power supply unit 70 so that the power of the power supply unit 70 is supplied to each part of the apparatus To be in a standby state.

The output of the filter unit 30 is output from the phase inversion and mixing unit 31 or the output of the frequency dispersion processing unit 32 or the phase inversion and mixing unit 32, (31) and the output of the frequency dispersion processing unit (32).

As described above, according to the present invention, the wearer who wears the noise reduction apparatus according to the present invention can turn on or off the operation of the present invention only by taking a predetermined motion, and can select the operation mode .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

10: microphone 20: modulation section
30: filter unit 31: phase inversion and mixing unit
32: Frequency dispersion processing unit 33: Mixing unit
40: demodulator 50: speaker

Claims (11)

A modulator (20) for converting the signal of the microphone (10) which detects the external noise into a digital signal;
A frequency dispersion processing unit 32 for receiving the digital signal of the modulation unit 20 and attenuating the intensity of the frequency signal higher than the predetermined intensity and increasing the frequency energy of the band adjacent to the attenuated frequency signal to output white noise, A filter unit 30 including the filter unit 30;
A demodulator 40 for converting an output signal of the filter unit 30 into an analog signal and outputting the analog signal through a speaker 50; And
And a motion sensor (80) for detecting the movement of the wearer,
The filter unit 30 includes a phase inverting and mixing unit 31 for receiving a digital signal of the modulating unit 20 and generating a signal whose phase is inverted and mixing the digital signal with the digital signal of the modulating unit 20 A mixer 33 for mixing and outputting the output signal of the phase inverting and mixing unit 31 and the signal of the frequency dispersion processing unit 32 and a mixer 33 which is operated under the control of the controller 60, Further comprising a switch unit for selecting output signals of the inversion and mixing unit 31 or the frequency dispersion processing unit 32 or the mixing unit 33 and outputting the selected signals to the demodulation unit 40,
The control unit 60 supplies or blocks the power or controls the switch unit according to the detection result of the motion sensor 80 to control the phase inversion and mixing unit 31 or the frequency dispersion processing unit 32, (33) is selected and output.
delete delete delete The method according to claim 1,
Further comprising a display unit (90) for displaying the remaining power level under the control of the controller (60).
The method according to claim 1,
The microphone 10, the modulator 20, the filter 30, the demodulator 40, and the speaker 50 are accommodated in a single case,
The case is a cannular structure in which a part is introduced into the ear canal and the other part is located outside the ear canal,
Wherein the portion of the ear hole is made of a material having excellent sound and sound.
a) converting an analog external noise into a digital noise signal;
b) generating a first white noise by attenuating the intensity of the frequency signal higher than the set intensity in the digital noise signal and increasing the frequency energy of the band adjacent to the attenuated frequency signal;
b-1) receiving the digital noise signal at the same time as the step b), generating a signal whose phase is inverted from the digital noise signal, mixing the signal with the generated phase-inverted signal and the digital noise signal, Producing two white noises;
b-2) mixing the second white noise and the first white noise to generate a third white noise; And
c) selecting the first white noise, the second white noise, or the third white noise according to the motion detection result of the user, and converting the selected first white noise or the third white noise into an analog signal and outputting the analog signal.
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