KR20210061055A - System and Method for Actively Reducing Noise Using Multi Channel - Google Patents

Abstract

According to one embodiment of the present invention, an active noise reduction system using a multichannel is capable of accurately predicting a target noise signal within a short time when noise is generated due to impact. The active noise reduction system comprises: a vibration sensor installed on a first ceiling construction material and sensing vibration generated by impact; first and second microphones installed on a second ceiling construction material and sensing noise generated by the impact; a noise delay distance calculating unit for calculating a noise delay distance based on the difference between a first time point at which the vibration is sensed by the vibration sensor and a second time point at which the noise is sensed by the first microphone; a target noise signal generator generating one of reference noise signals as a target noise signal by comparing at least one of a waveform of vibration and a waveform of the noise detected by the second microphone with the reference noise signals in a form of a synthesized wave composed of a fundamental wave and a plurality of harmonics; a target noise signal correcting unit correcting the target noise signal by correcting a phase of the target noise signal based on the noise delay distance; an offset signal generator generating an offset signal having a phase opposite to the phase of the target noise signal; and an offset signal output unit installed at the same point as the first microphone on the second ceiling construction material, and outputting the offset signal.

Description

System and Method for Actively Reducing Noise Using Multi Channel

The present invention relates to a noise reduction system, and more particularly, to a system capable of reducing the noise generated in the room.

Due to the increase in population, the housing type is changing from the existing single-family house type to the apartment house type such as apartment, officetel, and villa. Inter-floor noise refers to noise pollution in which the sound from the upper floors is transmitted to the lower floors in such apartments.

Active noise control that reduces noise by increasing the slab thickness to reduce inter-floor noise or by using a passive noise control method that reduces noise through sound-absorbing material construction, or by using extinction interference by offset sound whose phase is opposite to that of the noise and has the same frequency. The method is being applied.

However, the passive noise control method has a disadvantage in that it is effective in reducing the light weight impact sound to some extent, but is not effective in reducing the weight impact sound. In addition, since the active noise control method targets periodic noise, it is basically based on the Fast Fourier Transform (FFT) method. In the case of interlayer noise, since it is an impact noise that does not have periodicity, noise with periodicity When the general active noise reduction method targeting is applied, not only it is difficult to obtain an accurate noise waveform, but also a delay time in obtaining the noise waveform is inevitable, so that inter-floor noise is eliminated within a short time when inter-floor noise occurs. There is a downside that it cannot be done.

Republic of Korea Patent Registration No. 10-1647704 (Title of invention: Real-time monitoring system and monitoring method for noise between floors of apartment houses, Announcement date: August 11, 2016)

The present invention has been made to solve the above-described problem, and it is an object of the present invention to provide an active noise reduction system and method using multi-channels capable of accurately generating a target noise signal within a short time when noise is generated by an impact.

Another object of the present invention is to provide an active noise reduction system and method using multiple channels capable of generating a target noise signal by reflecting the noise delay distance.

An active noise reduction system using a multi-channel according to an aspect of the present invention for achieving the above object includes: a vibration sensor installed on a first ceiling building material and sensing vibration generated by an impact; First and second microphones installed on a second ceiling building material and sensing noise generated by the impact; A noise delay distance calculator configured to calculate a noise delay distance based on a difference between a first time point at which the vibration is sensed by the vibration sensor and a second time point at which the noise is sensed by the first microphone; Target noise by comparing at least one of the vibration waveform and the noise waveform detected by the second microphone with reference noise signals in the form of a composite wave composed of a fundamental wave and a plurality of harmonics A target noise signal generator that generates a signal; A target noise signal correction unit correcting the target noise signal by correcting a phase of the target noise signal based on the noise delay distance; A cancellation signal generator for generating a cancellation signal having a phase opposite to that of the target noise signal; And an offset signal output unit installed at the same point as the first microphone on the second ceiling building material and outputting the offset signal.

In one embodiment, the target noise signal generation unit compares the amplitude of the vibration and the amplitude of the reference noise signals at n reference points included in a predetermined first time interval (n is an integer of 3 or more), A reference noise signal having an amplitude equal to the amplitude of the vibration among the reference noise signals is generated as the target noise signal.

According to the above-described embodiment, the target noise signal generation unit, when there is no reference noise signal having the same amplitude as the amplitude of the vibration among the reference noise signals, n numbers included in the second predetermined time period. A reference noise having an amplitude equal to the amplitude of the noise generated by the second microphone among the reference noise signals by comparing the amplitude of the noise generated by the second microphone and the amplitude of the reference noise signals at a reference point in time. It is characterized in that the signal is generated as the target noise signal.

를 이용하여 위상 보정값을 산출하고, 산출된 위상 보정값을 상기 타겟 소음신호의 기본파 및 복수개의 고조파의 위상에 반영하여 상기 타겟 소음신호의 위상을 보정하고, 상기 수학식에서 φ_c는 상기 위상 보정값을 나타내고, S는 상기 소음지연거리를 나타내며, T는 상기 기본파 및 고조파의 주기를 나타내는 것을 특징으로 한다.In one embodiment, the noise delay distance calculation unit calculates a value obtained by multiplying a sound speed by a difference between the first and second time points as the noise delay distance, and the target noise signal correction unit comprises:

A phase correction value is calculated by using, and the phase of the target noise signal is corrected by reflecting the calculated phase correction value to the phases of the fundamental wave and a plurality of harmonics of the target noise signal, and φ _c is the phase It is characterized in that it represents a correction value, S represents the noise delay distance, and T represents the period of the fundamental and harmonics.

In the above-described embodiment, the active noise reduction system using multi-channel divides the target space in which the active noise reduction system is installed into a plurality of areas, and a location for determining a target area in which the user is located within the divided plurality of areas. Further comprising a determination unit, the cancellation signal output unit includes a plurality of speakers for outputting the cancellation signal for each of the regions, the cancellation signal generation unit generates the cancellation signal for each speaker, and the plurality of regions The amplitude of the canceling signal to be output through the speaker corresponding to the target area is set to be larger than the amplitude of the canceling signal to be output through the speaker corresponding to other areas except for the target area.

An active noise reduction method using a multi-channel according to an aspect of the present invention for achieving the above object includes the steps of detecting vibration and noise generated by impact, respectively; Comparing at least one of the vibration waveform and the noise waveform with reference noise signals in the form of a synthesized wave composed of a fundamental wave and a plurality of harmonics, and generating any one of the reference noise signals as a target noise signal; Correcting a phase of the target noise signal based on a noise delay distance calculated based on a difference between a first time point at which the vibration is sensed and a second time point at which the noise is sensed; Generating a cancellation signal having a phase opposite to that of the target noise signal; And outputting the cancellation signal.

In one embodiment, in the step of generating the target noise signal, the amplitude of the vibration and the amplitude of the reference noise signals at n reference points (n is an integer greater than or equal to 3) included in the first predetermined time period are determined. Each of the reference noise signals is compared, and a reference noise signal having an amplitude equal to the amplitude of the vibration is generated as the target noise signal.

In the step of generating the target noise signal according to the above-described embodiment, when there is no reference noise signal having the same amplitude as the amplitude of the vibration among the reference noise signals, n included in the second predetermined time period. Each of the amplitudes of the noise and the amplitudes of the reference noise signals are compared at each of the reference points, and a reference noise signal having the same amplitude as the amplitude of the noise among the reference noise signals is generated as the target noise signal. .

를 이용하여 산출되는 위상 보정값을 상기 타겟 소음신호의 기본파 및 복수개의 고조파의 위상에 반영하여 상기 타겟 소음신호의 위상을 보정하며, 상기 수학식에서 φ_c는 상기 위상 보정값을 나타내고, S는 상기 소음지연거리를 나타내며, T는 상기 기본파 및 고조파의 주기를 나타내는 것을 특징으로 한다.Meanwhile, in the step of correcting the target noise signal, a value obtained by multiplying the difference between the first time point and the second time point by a sound speed is calculated as the noise delay distance, and the equation

Corrects the phase of the target noise signal by reflecting the phase correction value calculated using the phase of the target noise signal and the phases of the plurality of harmonics, where φ _c represents the phase correction value, and S is It represents the noise delay distance, and T is characterized in that it represents the period of the fundamental wave and the harmonic.

In one embodiment, before the step of generating the offset signal, the target space to which the active noise reduction method is applied is divided into a plurality of regions, and a target region in which the user is located within the divided plurality of regions is determined. In the step of generating the cancellation signal, the plurality of regions are each generated with a cancellation signal to be output to the target region and a cancellation signal to be output to another region other than the target region, respectively, and to the target region. The amplitude of the canceling signal to be output is set to be larger than the amplitude of the canceling signal to be output to the other region.

According to the present invention, the target noise signal is generated in a short time without delay when noise is generated, because the target noise signal is generated based on the result of comparing the waveform within the first time interval among the vibration signals generated using the vibration sensor with the waveform of the reference noise signals. It has the effect of being able to accurately generate signals.

In addition, according to the present invention, the reference noise signals are stored in the lookup table in the form of a synthesized wave composed of a fundamental wave and a plurality of harmonics, and a target noise signal may also be generated in the form of a synthesized wave based on this, so that the conventional fast Fourier method Compared to the active noise control method using the method, it is possible to further shorten the time required for generating the target noise signal and to improve the accuracy of the target noise signal.

In addition, the present invention can maximize the accuracy of the target noise signal because the target noise signal is generated by reflecting the noise delay distance defined as the distance between the noise generation position and the speaker to which the cancellation signal is to be output. There is an effect that the accuracy of the cancellation signal for canceling can also be improved.

1 is a diagram showing the configuration of an active noise reduction system using multiple channels according to an embodiment of the present invention.
2 is a graph showing a time difference between a waveform of vibration detected by a vibration sensor and a waveform of noise detected by a microphone.
3 is a block diagram schematically showing the configuration of the controller 130 according to an embodiment of the present invention.
5 is a graph conceptually showing a method of comparing a vibration waveform or a noise waveform with a reference noise signal.
6 is a diagram illustrating an example of a lookup table in which reference noise signals are recorded in the form of a synthesized wave.
7 is a flowchart showing an active noise reduction method using multiple channels according to an embodiment of the present invention.

The same reference numbers throughout the specification mean substantially the same elements. In the following description, when not related to the core configuration of the present invention and detailed descriptions of configurations and functions known in the technical field of the present invention may be omitted. The meaning of the terms described in this specification should be understood as follows.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, and thus the present invention is not limited to the illustrated matters. The same reference numerals refer to the same elements throughout the specification. In addition, in describing the present invention, when it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

When'include','have','consists of' and the like mentioned in the present specification are used, other parts may be added unless'only' is used. In the case of expressing the constituent elements in the singular, it includes the case of including the plural unless specifically stated otherwise.

In interpreting the constituent elements, it is interpreted as including an error range even if there is no explicit description.

In the case of a description of a temporal relationship, for example, when a temporal predecessor relationship is described as'after','following','after','before', etc.,'right' or'direct' It may also include cases that are not continuous unless this is used.

First, second, etc. are used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, the first component mentioned below may be a second component within the technical idea of the present invention.

The term “at least one” is to be understood as including all possible combinations from one or more related items. For example, the meaning of “at least one of the first item, the second item, and the third item” means 2 among the first item, the second item, and the third item, as well as each of the first item, the second item, and the third item. It may mean a combination of all items that can be presented from more than one.

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other or can be implemented together in an association relationship. May be.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing the configuration of an active noise reduction system using multiple channels according to an embodiment of the present invention. The active noise reduction system (100, hereinafter referred to as'active noise reduction system') using multi-channels according to an embodiment of the present invention is installed in an apartment house, such as an apartment, officetel, or villa, and occurs between the upper and lower floors. It reduces the inter-floor noise. To this end, the active noise reduction system 100 according to the present invention, as shown in Figure 1, vibration sensor (VS1 ~ VSn), the first microphone (MC1), the second microphone (MC2-1 ~ MC2-n) , A controller 130, and a cancellation signal output unit 260. In addition, the active noise reduction system 100 according to the present invention may further include a camera 150.

First, the vibration sensors VS1 to VSn detect the vibration generated by the impact and transmit the detection result to the controller 130. In one embodiment, the vibration sensors VS1 to VSn may be installed on the first ceiling construction material 110 constituting the lower floor of the ceiling. For example, the first ceiling construction material 110 may be a concrete slab.

As shown in Figure 1, the vibration sensor (VS1 ~ VSn) is implemented in a plurality, each vibration sensor (VS1 ~ VSn) each senses the vibration generated by the shock, and the result individually to the controller 130. send. In FIG. 1, for convenience of explanation, three vibration sensors VS1 to VSn are shown, but this is only an example, and four or more vibration sensors VS1 to VSn may be implemented as two or less.

The first microphone MC1 detects noise generated by the impact and transmits the detection result to the controller 130. In one embodiment, the first microphone MC1 may be installed on the second ceiling construction material 120 constituting the lower floor ceiling. For example, the second ceiling construction material 120 may be a ceiling material.

In one embodiment, the first microphone MC1 detects noise to calculate a noise delay distance defined as the distance between the noise generation position and the offset signal output unit 260, and for more accurate noise delay distance calculation It may be installed at the same point as the point where the offset signal output unit 260 is installed on the second ceiling building material 120.

For example, when the offset signal output unit 260 is installed at a predetermined point on one side of the second ceiling building material 120, the first microphone MC1 is an offset signal on the other side of the second ceiling building material 120. It may be installed at a position corresponding to the point where the output unit 260 is installed.

The second microphones MC2a to MC2m detect noise generated by the impact and transmit the detection result to the controller 130. In one embodiment, the second microphones MC2a to MC2n may be installed on the second ceiling construction material 120 constituting the lower floor ceiling. As shown in FIG. 1, the second microphones MC2a to MC2n are implemented in plural, and the second microphones MC2a to MC2n respectively detect noise generated by the impact, and the result is individually controlled by the controller 130. Transfer to. In FIG. 1, it is shown that there are three second microphones MC2a to MC2m for convenience of explanation, but this is only an example, and the second microphones MC2a to MC2m may be implemented with four or more or two or less. .

According to the above-described embodiment, the first ceiling construction material 110 is positioned above the second ceiling construction material 120 based on a vertical direction to the ground, so that the first ceiling construction material Vibration sensors (VS1 ~ VSn) installed in 120 can detect the vibration before the first microphone (MC1) and the second microphone (MC2a ~ MC2m) installed on the second ceiling building material 120 . Accordingly, as shown in FIG. 2, the controller 130 detects the vibration 310 first detected by the vibration sensors VS1 to VSn by the first microphone MC1 and the second microphone MC2a to MC2m. Since the generated noise 320 can be obtained beforehand, a target noise signal and a cancellation signal for canceling the target noise can be generated in a short time.

In addition, according to the present invention, vibration and noise generated by shocks are prevented through a multi-channel method using a first microphone MC1 and a plurality of second microphones MC2a to MC2n in addition to a plurality of vibration sensors VS1 to VSn. Because of the detection, it is possible to accurately generate the target noise signal within a faster time.

The controller 130 generates a target noise signal based on the vibration detected by the plurality of vibration sensors VS1 to VSn and the noise detected by the first microphone MC1 and the plurality of second microphones MC2a to MC2n. Then, a cancellation signal for canceling the generated target noise signal is generated and provided to the cancellation signal output unit 260.

Hereinafter, the configuration of the controller 130 according to the present invention will be described in more detail with reference to FIG. 3.

3 is a block diagram schematically showing the configuration of the controller 130 according to an embodiment of the present invention. 3, the controller 130 according to the present invention includes a noise delay distance calculation unit 210, a target noise signal generation unit 220, a look-up table 230, a target noise signal correction unit 240, And a cancellation signal generation unit 250.

The noise delay distance calculation unit 210 calculates a noise delay distance defined as the distance between the noise generation position and the offset signal output unit 260. In one embodiment, the noise delay distance calculation unit 210 calculates a difference between a first time point at which vibration is sensed by the vibration sensors VS1 to VSn and a second time point at which noise is sensed by the first microphone MC1. The noise delay distance can be calculated by calculating and multiplying the calculated result value by the speed of sound. In this case, the speed of sound may be defined as 340 m/s.

According to the above-described embodiment, the noise delay distance calculation unit 210 sets the time when the vibration is detected by the vibration sensor that first detects the vibration among the plurality of vibration sensors VS1 to VSn as the first time point. I can. To this end, each of the vibration sensors VS1 to VSn may transmit a vibration detection result to the noise delay distance calculation unit 210 together with information about the time point at which the vibration is sensed. In another embodiment, each vibration sensor (VS1 ~ VSn) transmits only the vibration detection result to the noise delay distance calculation unit 210, the noise delay distance calculation unit 210 from each vibration sensor (VS1 ~ VSn) The first time point at which the vibration detection result is received may be defined as the first time point.

On the other hand, the first microphone MC1 also transmits the noise detection result to the noise delay distance calculation unit 210 together with the time information at which the noise is detected, and the noise delay distance calculation unit 210 is the first microphone MC1 A point in time at which noise is detected may be set as a second point in time. In another embodiment, the first microphone MC1 transmits only the noise detection result to the noise delay distance calculation unit 210, and the noise delay distance calculation unit 210 receives the noise detection result from the first microphone MC1. The point in time can be defined as the second point in time.

The target noise signal generation unit 220 converts the vibration detected by the vibration sensors VS1 to VSn and the noise detected by the second microphones MC2a to MC2n to a plurality of reference noise signals recorded in the lookup table 230 and It compares, and generates any one of a plurality of reference noise signals as a target noise signal according to the comparison result.

First, the target noise signal generation unit 220 compares the waveform of the vibration detected by the vibration sensors VS1 to VSn with a plurality of reference noise signals recorded in the lookup table 230. In this case, the target noise signal generation unit 220 may compare the waveform of the vibration of the vibration sensor that first detected the vibration among the vibration sensors VS1 to VSn with the reference noise signal.

Specifically, as shown in FIG. 4, the target noise signal generation unit 220 includes n (n is an integer of 3 or more) reference time points (eg, 3 (t1)) within a predetermined first time period (P1). , t2, t3)), and the amplitude (a1, a2, a3) of the vibration 310 detected by the vibration sensor (VS1 to VSn) for each reference point (t1, t2, t3) and a lookup table 230 The amplitudes (a1', a2', a3') of the reference noise signals 410 recorded in) are compared. The target noise signal generator 220 generates, as a target noise signal, one reference noise signal having the same amplitude as the amplitude of the vibration detected by the vibration sensors VS1 to VSn among the reference noise signals.

In one embodiment, a plurality of reference noise signals may be recorded in the lookup table 230 in the form of a composite wave composed of a fundamental wave and a plurality of harmonics. It is generated in the form of a composite wave composed of harmonics.

An example of a lookup table 230 in which reference noise signals are recorded in the form of a synthesized wave is shown in FIG. 5. As shown in FIG. 5, it is noted that the angular velocity (W1 to Wn), the amplitude for each angular velocity (a0 to a1), and the phase for each angular velocity (φ1 to φn) are recorded for each of the reference noise signals RSN1 to RSNn. Able to know.

5 shows that the angular velocity of each of the reference noise signals is recorded in the lookup table 230, this is only an example, and the amplitude and phase may be recorded for each frequency of the fundamental wave and the frequency of each harmonic. In addition, the period of each of the reference noise signals RSN1 to RSNn may be additionally recorded in the lookup table 230.

In the case of the above-described embodiment, the target noise signal generation unit 220 uses information on the reference noise signals recorded in the lookup table 230 to calculate the amplitude of the reference noise signals at each reference point. The amplitude at each reference point can be calculated by restoring the signals in the form of a function defining one synthesized wave, and substituting the reference point into the restored function.

The target noise signal generator 220 may define the reference noise signals recorded in the lookup table 230 illustrated in FIG. 5 as a function of the form described in Equation 1 below.

On the other hand, when there is no reference noise signal having the same amplitude as the amplitude of the vibration detected by the vibration sensors VS1 to VSn on the lookup table 230 of the target noise signal generator 220, the second microphone MC2a to A target noise signal is generated by additionally comparing the waveform of the noise generated by MC2n) with a plurality of reference noise signals recorded in the lookup table 230. In this case, the target noise signal generator 220 may compare the waveform of the noise of the second microphone, which first detects the noise among the second microphones MC2a to MC2n, with the reference noise signal.

Specifically, when there is no reference noise signal having the same amplitude as the amplitude of the vibration detected by the vibration sensors VS1 to VSn on the lookup table 230, the target noise signal generation unit 220 Set n reference points within the time period, and the amplitude of the noise generated by the second microphone (MC2a~MC2n) for each reference point (t1, t2, t3) and the reference noise signal recorded in the lookup table 230 Compare the amplitudes of each. The target noise signal generator 220 generates, as a target noise signal, one reference noise signal having the same amplitude as the amplitude of the noise generated by the second microphones MC2a to MC2n among the reference noise signals. In this case, since the second time period is set to a longer time than the first time period, the possibility of generating the target noise signal from the look-up table 230 may be further increased.

The target noise signal correction unit 240 calculates a phase correction value using the noise delay distance calculated by the noise delay distance calculation unit 210, and the target noise signal generation unit 220 using the calculated phase correction value. The phase of the target noise signal generated by is corrected. In an embodiment, the target noise signal corrector 240 may calculate a phase correction value using Equation 1 below.

In Equation 1, φ _c denotes a phase correction value, S denotes a noise delay distance, and T denotes a period of a fundamental wave and a period of harmonics constituting the target noise signal, respectively.

In an embodiment, the target noise signal correction unit 240 may correct the phase of the target noise signal by adding the calculated phase correction value to the phase of the fundamental wave and the phase of the harmonic of the target noise signal, respectively.

The cancellation signal generation unit 250 generates a cancellation signal based on the target noise signal corrected by the target noise signal correction unit 240. Specifically, the cancellation signal generation unit 250 generates a cancellation signal having a phase opposite to that of the corrected target noise signal. As described above, the present invention generates a cancellation signal having a phase opposite to that of the corrected target noise signal so that extinction interference may occur between the cancellation signal and the target noise signal, thereby reducing the target noise signal.

The cancellation signal output unit 260 outputs a cancellation signal generated by the cancellation signal generation unit 250. In one embodiment, the cancellation signal output unit 260 may include an amplification unit 252 and a speaker 254 as shown in FIG. 3.

The amplifying unit 252 amplifies the canceling signal generated by the canceling signal generating unit 250 and outputs it to the speaker 254, and the speaker 254 outputs the canceling signal amplified by the amplifying unit 252 to the outside. do.

In one embodiment, the cancellation signal output unit 260 may include a plurality of speakers 254a to 254n as shown in FIG. 3. For example, the cancellation signal output unit 260 may include two speakers 254a and 254b as shown in FIG. 6A. In this case, each of the speakers 254a and 254b may be installed in a direction in which canceling signals output from the corresponding speakers 254a and 254b do not interfere with each other. As another example, the cancellation signal output unit 260 may include three speakers 254a, 254b, and 254c as shown in FIG. 6B. In this case, each of the speakers 254a to 254c may be installed in a direction in which canceling signals output from the corresponding speakers 254a to 254c do not interfere with each other.

As described above, when the offset signal output unit 260 includes a plurality of speakers 254a to 254n, the controller 130 according to the present invention is a space in which the active noise reduction system 100 according to the present invention is installed ( Hereinafter, the user's position is determined within the'target space'), and the canceling signal to be output by at least one of the speakers 254a to 254n is outputted by the other speakers according to the determined user's position. It can be created differently from the signal.

To this end, the active noise reduction system 100 according to the present invention may further include a camera 150 as shown in FIGS. 1 and 3, and the controller 130 determines a location as shown in FIG. 3. A unit 260 may be further included.

First, the camera 150 photographs a target space and provides the captured image to the positioning unit 260 included in the controller 130.

The positioning unit 260 determines a target area in which the user is located in the target space based on the image provided from the camera 150. To this end, the positioning unit 260 according to the present invention divides the target space into a plurality of areas, and determines a target area in which the user is located within the divided plurality of areas.

The location determination unit 260 provides information on the target area determined to be located in the user to the offset signal generation unit 250.

The cancellation signal generation unit 250 generates, for each speaker 254a to 254n, a cancellation signal having a phase opposite to that of the target noise signal based on the information on the target region. Specifically, each speaker (254a ~ 254n) is mapped 1:1 with a plurality of regions constituting the target space, and the cancellation signal generator 250 generates a cancellation signal having a phase opposite to that of the target noise signal. After that, the amplitude of the canceling signal to be output through the speaker corresponding to the target area may be set to be larger than the amplitude of the canceling signal to be output through the speaker corresponding to other areas except for the target area.

Through this, a stronger cancellation signal can be transmitted to the target region in which the user is located, so that the target noise signal can be more efficiently reduced in the target region.

Hereinafter, an active noise reduction method using multiple channels according to the present invention will be described with reference to FIG. 7. 7 is a flowchart showing an active noise reduction method using multiple channels according to an embodiment of the present invention. The active noise reduction method using multiple channels shown in FIG. 7 may be performed by the active noise reduction system using multiple channels shown in FIG. 1.

First, the active noise reduction system 100 detects vibration and noise generated by the impact (S700). In one embodiment, the vibration generated by the impact can be detected by a plurality of vibration sensors installed on the first ceiling building material, and the noise generated by the impact is the first and second installed on the second ceiling building material. It can be detected by the second microphone.

Thereafter, the active noise reduction system 100 determines whether a reference noise signal identical to the waveform of the vibration sensed in S700 exists among the reference noise signals in the form of a composite wave composed of a fundamental wave and a plurality of harmonics (S720). In one embodiment, the active noise reduction system 100 determines n reference points (n is an integer of 3 or more) within a predetermined first time period, and an amplitude equal to the amplitude of the vibration detected at the determined reference point. When there is a reference noise signal having a, it is determined that a reference noise signal identical to the waveform of the sensed vibration exists.

As a result of the determination of S720, the active noise reduction system 100 generates a corresponding reference noise signal as a target noise signal if the same reference noise signal as the detected vibration waveform exists (S730).

On the other hand, if there is no reference noise signal identical to the waveform of the detected vibration as a result of the determination of S720, the active noise reduction system 100 is the same as the waveform of the noise detected by the plurality of second microphones among the reference noise signals. It is further determined whether a signal exists (S740).

Specifically, the active noise reduction system 100 determines n reference points (n is an integer of 3 or more) within a predetermined second time period, and a reference having the same amplitude as the amplitude of the noise detected at the determined reference point. When there is a noise signal, it is determined that there is a reference noise signal identical to the waveform of the detected noise.

As a result of the determination of S740, the active noise reduction system 100 generates a corresponding reference noise signal as a target noise signal if there is a reference noise signal identical to the waveform of the detected noise (S730). On the other hand, as a result of the determination of S740, if the same reference noise signal as the detected noise waveform does not exist, the active noise reduction system 100 returns to S700 to detect new vibrations and noise.

Thereafter, the active noise reduction system 100 calculates the noise delay distance based on the difference between the first time point at which the vibration is sensed and the second time point at which the noise is sensed in S700 (S745), and then based on the calculated noise delay distance. The phase of the target noise signal generated in S730 is corrected (S750).

In one embodiment, the active noise reduction system 100 may calculate the noise delay distance by multiplying the difference between the first time point at which the vibration is sensed and the second time point at which the noise is sensed by the speed of sound. In this case, the speed of sound may be defined as 340 m/s.

According to the above-described embodiment, the active noise reduction system 100 sets the time when the vibration is detected by the vibration sensor that first detects the vibration among the plurality of vibration sensors as the first time point, or the respective vibration sensors The first time point at which the vibration detection result is received may be defined as the first time point. In addition, the active noise reduction system 100 may define a time when noise is detected by the first microphone or a time when a noise detection result is received from the first microphone as a second time point.

Meanwhile, the active noise reduction system 100 may calculate a phase correction value by substituting the noise delay distance in Equation 2 above, and use the calculated phase correction value to determine the phase and harmonics of the fundamental wave of the target noise signal. The phase of the target noise signal can be corrected by adding each of the phases of.

Thereafter, the active noise reduction system 100 generates a cancellation signal based on the target noise signal corrected in S750 (S760). Specifically, the active noise reduction system 100 may generate a cancellation signal having a phase opposite to that of the corrected target noise signal. As described above, the present invention generates a cancellation signal having a phase opposite to that of the corrected target noise signal so that extinction interference may occur between the cancellation signal and the target noise signal, thereby reducing the target noise signal.

Thereafter, the active noise reduction system 100 amplifies the cancellation signal generated in S760 and outputs it through the speaker (S770).

In one embodiment, the active noise reduction system 100 may output a cancellation signal through a plurality of speakers. According to this embodiment, the active noise reduction system 100 determines the user's location in the target space where the system 110 is installed, and outputs at least one of the speakers according to the determined user's location. It is possible to generate a canceling signal to be performed differently from the canceling signal to be output by other speakers.

Specifically, the active noise reduction system 100 divides the target space into a plurality of areas, and determines an area in which the user is located within the divided plurality of areas. Thereafter, the active noise reduction system 100 generates, for each speaker, a cancellation signal having a phase opposite to the phase of the target noise signal based on the information on the target area, but the cancellation signal to be output through the speaker corresponding to the target area The amplitude may be set to be larger than the amplitude of the cancellation signal to be output through the speaker corresponding to the other area except the target area.

Through this, a stronger cancellation signal can be transmitted to the target region in which the user is located, so that the target noise signal can be more efficiently reduced in the target region.

Those skilled in the art to which the present invention pertains will be able to understand that the above-described present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof.

In addition, the components described herein may be implemented, at least in part, using one or more computer programs or components. This component is a series of computer-readable or machine-readable media including volatile and non-volatile memory such as RAM, ROM, flash memory, magnetic or optical disks, optical memory, or other storage media. It can be provided as computer directives. The directives may be provided as software or firmware, and may, in whole or in part, be implemented in a hardware configuration such as ASICs, FPGAs, DSPs, or any other similar device. The directives may be configured to be executed by one or more processors or other hardware configurations, wherein the processor or other hardware configurations perform all or part of the methods and procedures disclosed herein when executing the series of computer directives, or To be able to perform.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention do.

100: active noise reduction system 130: controller
210: noise delay distance calculation unit 220: target noise signal generation unit
230: lookup table 240: target noise signal correction unit
250: offset signal generation unit 260: offset signal output unit

Claims (10)

A vibration sensor installed on a first ceiling building material and sensing vibration generated by an impact;
First and second microphones installed on a second ceiling building material and sensing noise generated by the impact;
A noise delay distance calculator configured to calculate a noise delay distance based on a difference between a first time point at which the vibration is sensed by the vibration sensor and a second time point at which the noise is sensed by the first microphone;
At least one of the vibration waveform and the noise waveform detected by the second microphone is compared with reference noise signals in the form of a composite wave composed of a fundamental wave and a plurality of harmonics, and any one of the reference noise signals is selected as a target noise. A target noise signal generator that generates a signal;
A target noise signal correction unit correcting the target noise signal by correcting a phase of the target noise signal based on the noise delay distance;
A cancellation signal generator for generating a cancellation signal having a phase opposite to that of the target noise signal; And
An active noise reduction system using a multi-channel, characterized in that it is installed on the second ceiling building material at the same point as the first microphone, and comprises a cancellation signal output unit configured to output the cancellation signal. The method of claim 1,
The target noise signal generation unit compares the amplitude of the vibration and the amplitude of the reference noise signals at n reference points included in a predetermined first time period (n is an integer of 3 or more), and among the reference noise signals Active noise reduction system using multiple channels, characterized in that generating a reference noise signal having the same amplitude as the amplitude of the vibration as the target noise signal. The method of claim 2,
When the reference noise signal having the same amplitude as the amplitude of the vibration among the reference noise signals does not exist, the target noise signal generator is The amplitude of the noise generated by the noise and the amplitude of the reference noise signals are respectively compared, and a reference noise signal having the same amplitude as the amplitude of the noise generated by the second microphone among the reference noise signals is generated as the target noise signal. Active noise reduction system using multiple channels, characterized in that. The method of claim 1,
The noise delay distance calculating unit calculates a value obtained by multiplying the difference between the first point in time and the second point in time by a sound speed as the noise delay distance,
The target noise signal correction unit, Equation

A phase correction value is calculated using, and the phase correction value of the target noise signal is corrected by reflecting the calculated phase correction value to the phases of the fundamental wave and the plurality of harmonics of the target noise signal,
In the above equation, φ _c represents the phase correction value, S represents the noise delay distance, and T represents the period of the fundamental and harmonics. The method of claim 1,
Further comprising a positioning unit for dividing the target space in which the active noise reduction system is installed into a plurality of areas, and determining a target area in which the user is located within the divided plurality of areas,
The cancellation signal output unit includes a plurality of speakers for outputting the cancellation signal for each region,
The canceling signal generator generates the canceling signal for each speaker, and outputs the amplitude of the canceling signal to be output through a speaker corresponding to the target area among the plurality of areas through a speaker corresponding to another area except the target area. Active noise reduction system using multi-channel, characterized in that set to be larger than the amplitude of the cancellation signal. Detecting vibration and noise generated by the impact, respectively;
Comparing at least one of the vibration waveform and the noise waveform with reference noise signals in the form of a synthesized wave composed of a fundamental wave and a plurality of harmonics, and generating any one of the reference noise signals as a target noise signal;
Correcting a phase of the target noise signal based on a noise delay distance calculated based on a difference between a first time point at which the vibration is sensed and a second time point at which the noise is sensed;
Generating a cancellation signal having a phase opposite to that of the target noise signal; And
And outputting the cancellation signal. The method of claim 6,
In the step of generating the target noise signal, the amplitude of the vibration and the amplitude of the reference noise signals are respectively compared at n reference points included in a predetermined first time period (n is an integer of 3 or more), and the reference An active noise reduction method using multiple channels, characterized in that, among noise signals, a reference noise signal having an amplitude equal to the amplitude of the vibration is generated as the target noise signal. The method of claim 7,
In the step of generating the target noise signal, when there is no reference noise signal having the same amplitude as the amplitude of the vibration among the reference noise signals, the noise at n reference points included in a second predetermined time period. An active noise using multi-channel, characterized in that comparing the amplitude of and the amplitudes of the reference noise signals, and generating a reference noise signal having the same amplitude as the amplitude of the noise among the reference noise signals as the target noise signal. Reduction method. The method of claim 6,
In the step of correcting the target noise signal,
A value obtained by multiplying the sound speed by the difference between the first and second time points is calculated as the noise delay distance,
Equation

Correcting the phase of the target noise signal by reflecting the phase correction value calculated by using the phase of the fundamental wave and a plurality of harmonics of the target noise signal,
In the above equation, φ _c represents the phase correction value, S represents the noise delay distance, and T represents the period of the fundamental and harmonics. The method of claim 6,
Before the step of generating the offset signal, further comprising the step of dividing the target space to which the active noise reduction method is applied into a plurality of regions, and determining a target region in which the user is located within the divided plurality of regions,
In the step of generating the canceling signal, each of the plurality of areas to generate a canceling signal to be output to the target area and a canceling signal to be output to other areas other than the target area, and the amplitude of the canceling signal to be output to the target area The active noise reduction method using a multi-channel, characterized in that set to be larger than the amplitude of the cancellation signal to be output to the other region.

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