KR101875273B1 - Apparatus and Method for estimating position of acoustic source using Time Difference Of Arrival scheme based on sound wave directly transmitted from acoustic source and sound wave measurement reflected from the ground - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound source estimation technique, and more particularly, to a sound source estimation technique using a time difference between arrival (TDOA) technique between sound signal channels provided through a microphone array, The present invention relates to an apparatus and a method for accurately estimating a position of a noise source by assuming a virtual sensor on the ground using a signal of a sound wave transmitted after reflecting the ground surface.
According to the present invention, a measured signal reflected on the ground surface has the same effect as measured by the existence of a virtual sensor on the opposite side of the ground, and can be used to produce an increased sensor combination.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for estimating a sound source position using a delay time arrival technique based on a sound wave propagated directly from a sound source and a sound wave reflected on the ground, < / RTI > transmitted from an acoustic source and a sound wave measurement reflected from the ground.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound source estimation technique, and more particularly, to a sound source estimation technique using a time difference between arrival (TDOA) technique between sound signal channels provided through a microphone array, The present invention relates to an apparatus and a method for accurately estimating a position of a noise source by assuming a virtual sensor on the ground using a signal of a sound wave transmitted after reflecting the ground surface.

 Explosion location measurement of shell performance evaluation in weapon system development is an important test evaluation index to confirm fuse performance. Accurate measurement techniques are therefore required to determine whether an explosion has occurred at the correct location. Noise source location tracking system using acoustic sensor is suitable for use in a wide range of weapon test sites and various prior studies are being conducted.

When the explosive is activated, a strong impact sound is generated. Since the signal is clear and the signal is easy to acquire, and the microphone used as the acoustic sensor is smaller than the equipment such as the image and the radar, and the cost is low, . A variety of algorithms have been developed for the noise source location tracking method using the microphone array, depending on the characteristics of the noise source and the experimental environment.

Particularly, in the case of measuring an impact sound that explodes in the air, studies are being conducted to estimate the location of an impact sound using a Time Difference of Arrival (TDOA). The noise source position estimation method using the arrival delay time can theoretically estimate the position of the noise source in the space by using three or more microphones. However, it is necessary to increase the number of microphones or to increase the estimation accuracy by various arrangements because it directly affects the measurement results depending on the measurement environment and the arrangement method.

1. Korean Patent Publication No. 1020040092152

1. Prediction of Flying Orbit Parameters Using Acoustic Reflection Effect by Ground, "Proceedings of the Military Science and Technology Conference, 2014, Seoul, Korea. 2. Ahn BW, et al., "Position tracking of underwater noise sources using arrival delay time technique", Journal of the Society of Naval Architects of Korea, Vol. 48, No. 2, pp.

The present invention has been proposed in order to solve the above problem, and it is an object of the present invention to provide a delay time estimation method and a delay time estimation method capable of estimating a location of an impact sound using a Time Difference of Arrival (TDOA) And an object of the present invention is to provide an apparatus and method for estimating a sound source position using an arrival technique.

It is another object of the present invention to provide an apparatus and method for estimating a sound source position using a delay time arrival technique that can improve estimation accuracy of an impact sound explosion in the air.

In order to achieve the above object, the present invention provides a delay time arrival technique capable of estimating the location of an impact sound using time delay difference arrival (TDOA) when measuring an impact sound explosion in the air And provides a sound source position estimating device.

The sound source position estimating apparatus comprises:

A signal acquiring unit acquiring an acoustic signal of a sound source from a microphone array composed of a plurality of microphones;

A virtual sensor generating unit for generating a plurality of virtual sensors corresponding to the plurality of microphones;

A sensor pair combining unit for combining the plurality of microphones and the plurality of virtual sensors into each pair;

A time delay between the direct sound wave signal and the surface-reflected sound wave signal is calculated using the direct sound wave signal transmitted directly by the combination and the surface-reflected sound wave signal transmitted by ground reflection to generate arrival delay time simultaneous equations information Calculating section; And

And a position estimator for estimating the final position information of the sound source using the arrival delay time simultaneous equations information.

The plurality of virtual sensors may be characterized in that the coordinate information is set assuming that the coordinate information of the plurality of microphones at a predetermined height above the ground is symmetric with respect to the ground.

The time delay between the sound signals may be calculated through a cepstrum.

The coordinate information of the plurality of microphones may be determined by a position on the two-dimensional plane of the plurality of microphones and a height of the microphones on the ground.

In addition, the final position information may be sound source position information in a three-dimensional space.

The final position information of the sound source may be a simultaneous equations solution of the simultaneous equations information using the least squares method.

(여기서,

는

에서 측정된 신호의 파워 캡스트럼 함수를 나타내며,

는 i번째 마이크로폰 위치를 나타내며,

이고, FFT는 고속 푸리에 변환(fast Fourier transform)이고, IFFT는 역고속 푸리에 변환(inverse fast Fourier transform)을 나타내고, x(t)는 x좌표의 시간함수를 나타낸다)으로 산출되는 것을 특징으로 할 수 있다.Also, the time delay between the direct sound wave signal and the ground-

(here,

The

Lt; / RTI > represents the power capstrum function of the signal measured at < RTI ID =

Represents the i-th microphone position,

, The FFT is a fast Fourier transform, the IFFT is an inverse fast Fourier transform, and x (t) is a time function of an x coordinate). have.

According to another embodiment of the present invention, there is provided a method of generating a sound signal, the method including: acquiring an acoustic signal of a sound source using a microphone array having a plurality of microphones; The virtual sensor generating unit generating a plurality of virtual sensors corresponding to the plurality of microphones; Combining the sensor pair combination with the plurality of microphones and the plurality of virtual sensors in each pair; Calculating a delay time between the direct sound wave signal and the surface-reflected sound wave signal by using the direct sound wave signal transmitted directly by the combination and the surface-reflected sound wave signal transmitted by ground reflection; Generating the delay time alignment equation information by using the time delay between the direct sound signal and the surface acoustic wave signal; And estimating the final position information of the sound source using the arrival delay time simultaneous equations information. The method of claim 1, It is possible to provide a sound source position estimation method using a time arrival technique.

 According to the present invention, a measured signal reflected on the ground surface has the same effect as measured by the presence of a virtual sensor on the opposite side of the ground, and can be used to produce an increased sensor combination.

As another effect of the present invention, a TDOA (Time Difference of Arrival) technique is applied as an increased number of sensors through an increased sensor combination to estimate a position estimation accuracy of a noise source (e.g., explosion of a shell) And the like.

FIG. 1 is a block diagram of a position estimation apparatus 100 using a ground reflection effect based TDOA (Time Difference of Arrival) technique according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram showing a propagation path of sound due to ground reflection according to an embodiment of the present invention.
FIG. 3 is a signal diagram in which the ground-reflected sound pressure signal shown in FIG. 2 is received by the acoustic sensor.
FIG. 4 is a conceptual diagram showing that a sound pressure signal generated by a floor reflection effect according to an embodiment of the present invention is virtually the same as that received by a virtual sensor on the opposite side of the ground.
FIG. 5 is a conceptual diagram for creating a delay time relation pair combination including a virtual sensor in a plurality of sensor combinations according to an embodiment of the present invention. FIG.
FIG. 6 is a flowchart illustrating a process of estimating a position using a ground reflection effect based TDOA (Time Difference of Arrival) technique according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term " and / or " includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus and method for estimating a sound source position using a delay time arrival technique based on a sound wave directly propagated in a sound source and a sound wave reflected on the ground according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings do.

FIG. 1 is a block diagram of a position estimation apparatus 100 using a ground reflection effect based TDOA (Time Difference of Arrival) technique according to an embodiment of the present invention. 1, the position estimation apparatus 100 includes a signal acquisition unit 110 for acquiring sound signals of a sound source through a plurality of microphones, a virtual sensor generation unit 120 for generating a plurality of virtual sensors, A sensor pair combining unit 130 for combining the microphone and the plurality of virtual sensors into each pair, a delay time calculating unit 140 for calculating the time delay between the acoustic signals by the combination and generating arrival delay time simultaneous equations information, And a position state determiner 150 for estimating the final position information of the sound source using the arrival delay time simultaneous equations information.

Here, the plurality of microphones may be composed of the microphone array 10.

The virtual sensor generation unit 120 generates a plurality of virtual sensors corresponding to a plurality of microphones. In other words, the coordinates are set assuming that there is a virtual microphone (ie, a virtual sensor) that is symmetrically symmetrical to the ground, with the coordinates of the microphone array at a certain height above the ground.

The delay time calculation unit 140 performs a sound wave measurement directly transmitted through the plurality of microphones and the sound waves transmitted through the ground reflection, calculates the time delay between the sound signals using the sound waves, and generates arrival delay time simultaneous equations information .

FIG. 2 is a conceptual diagram showing a propagation path of sound due to ground reflection according to an embodiment of the present invention. Referring to FIG. 2, in a wide range of explosive test sites, a noise source 220 is generally measured by installing a microphone 210 on the ground 230. The impact sound generated by the air explosion is propagated into the air and is received by the microphone 210 on the ground. This is referred to as a directly transmitted sound wave path (R _i ).

On the other hand, in the case of a microphone fixed at a specific height above the ground, a phenomenon occurs in which a sound pressure signal reflected on the ground is added to the sound, and this phenomenon is referred to as a reflection effect. This is called a reflected sound wave path (R _i *).

The acoustic signal reflected on the ground is measured after a certain time because the difference between the direct received signal and the propagation path occurs. The cepstrum analysis method calculates the delay time by separating the direct sound wave signal measured from a single microphone and the ground reflection sound wave signal. Since the propagation path of the ground reflection signal is geometrically symmetrical to the ground, it can be applied as a virtual measurement point.

FIG. 3 is a signal diagram in which the ground-reflected sound pressure signal shown in FIG. 2 is received by the acoustic sensor. 3, the ground between the sound wave and the reflected sound wave signal directly to the signal delay time (τ ^* _ii) is equal to the expression.

Here, R _i is a directly transmitted sound wave path, R _i * is a reflected sound wave path, and c indicates a sound velocity.

의 차이에 의하여 발생한다. FIG. 4 is a conceptual diagram showing that a sound pressure signal generated by a floor reflection effect according to an embodiment of the present invention is virtually the same as that received by a virtual sensor on the opposite side of the ground. Referring to FIG. 4, assuming the noise radiated from the point source to the spherical wavefront, the geometrical positional relationship between the noise source 220 and the respective microphones has a relative distance difference, and is measured as a signal having a different phase when compared at the same time . The phase of the measured signals from each of the two microphones is determined by the distance

.

에 의하여 위상차이가 발생하고 다음식에 의하여 도달지연거리

와 음속

의 관계로 계산된다. When the actual signal is measured, the arrival delay time

The phase difference is generated by the following equation

And sound speed

.

는 i와 j 마이크로폰 까지 거리,

는 소음원으로부터 i 마이크로폰 까지 거리를 나타내고, c는 다음식과 같다.here,

Is the distance to i and j microphones,

Represents the distance from the noise source to i microphone, and c is the following equation.

는 대기 온도를 나타낸다.here,

Represents the atmospheric temperature.

에 의하여 계산하며, 다음식과 같다.The arrival delay time is the cross-correlation function

Is calculated by the following equation.

는 i와 j 마이크로폰 신호의 지연시간을 나타내고, τ는 도달지연시간을 나타낸다.here,

Represents the delay time of the i and j microphone signals, and t represents the arrival delay time.

는 다음식과 같다.Cross-correlation function

Is as follows.

Here, T is time, x (t) is time function of x coordinate, and y (t) is time function of y coordinate.

개의 마이크로폰을 사용하였을 경우 도달지연시간을 계산할 수 있는 쌍의 개수는

개이다. 계산된 각각의 도달지연거리는 도 2와 같이 쌍곡선 형태로 나타나며 이 쌍곡선들의 교점이 소음원의 위치 추정 결과이다. 이 기법에서는 쌍곡선에 의한 기하학적 교점을 찾는 추정 방법 대신에 테일러 급수를 이용하여 수렴 오차가 최소인 지점을 찾는 수치적 방법을 통하여 위치를 추정하도록 할 수 있다. 이를 수학식으로 나타내면 다음과 같다.The position of the noise source can be estimated when measuring signals from at least three microphones.

The number of pairs that can calculate the arrival delay time when using two microphones is

Dog. Each of the calculated arrival delay distances is shown in a hyperbolic shape as shown in FIG. 2. The intersection point of the hyperbolas is a result of the position estimation of the noise source. In this technique, instead of estimating the geometric intersection by hyperbola, the Taylor series can be used to estimate the position using a numerical method to find the point where the convergence error is minimum. This can be expressed by the following equation.

는

에서 측정된 신호의 파워 캡스트럼 함수를 나타내며,

는 i번째 마이크로폰 위치를 나타낸다.here,

The

Lt; / RTI > represents the power capstrum function of the signal measured at < RTI ID =

Represents the i-th microphone position.

가 되도록 하였다.The convergence error is approximate to the direction of each axis of the Cartesian coordinate system.

Respectively.

The microphone, which is fixed at a fixed height above the ground, is measured by the combination of a direct sound signal incident on a linear path in the air and a ground reflected sound signal on which a signal reflected on the ground is incident. 3 shows the paths of a direct acoustic wave signal and a ground reflection acoustic wave signal that are incident on a microphone.

는 지면(230)을 기준으로 실제 마이크로폰 위치

와 대칭인 위치

에 대한 도달거리

와 같다. 지면반사효과에 의하여 측정되는 직접 음파 신호와 지면 반사 음파 신호는 도 4에 도시된 바와 같다. 직접 음파 신호와 지면 반사 음파 신호의 경로차이에서 나타나는 지연시간

는 다음식의 캡스트럼 및 수학식 6에 의해서 측정된다.4, reflection of a signal occurs at a point where the incident angle and the reflection angle at the ground surface are the same. Ground reflection Sound wave signal reach distance

The actual microphone position < RTI ID = 0.0 >

And symmetric position

Reach for

. The direct sound wave signal and the ground reflection sound wave signal measured by the ground reflection effect are as shown in FIG. The delay time that appears from the path difference between the direct sound signal and the ground reflection sound signal

Is measured by the following expression and the expression (6).

Here, the FFT is a fast Fourier transform and the IFFT is an inverse fast Fourier transform.

사이의 도달지연시간으로 가정할 수 있다. 한 쌍으로 구성되는 제 1 및 제 2 마이크로폰

,

(511,512)에 대한 상호상관함수로부터

, 각 마이크폰의 캡스트럼으로부터

,

가 각각 계산되며 이를 표로 나타내면 다음과 같다. FIG. 5 is a conceptual diagram for creating a delay time relation pair combination including a virtual sensor in a plurality of sensor combinations according to an embodiment of the present invention. FIG. First, the delay time of the surface-reflected sound wave signal measured by the capstrum is calculated by multiplying the measured microphone position and the virtual microphone position

As shown in FIG. The first and second microphones

,

(511, 512) from the cross-correlation function

, From each microphone's Capstrum

,

Are calculated as follows.

pair τ calculation Remarks i, j

Direct sonic signal i, i ^*

Direct sound wave signal + ground reflection sound wave signal i, j ^*

=

+

Direct sound wave signal + ground reflection sound wave signal j, i ^*

=

+

Direct sound wave signal + ground reflection sound wave signal j, j ^*

Direct sound wave signal + ground reflection sound wave signal i ^* , j ^*

=

+

-

Direct sound wave signal + ground reflection sound wave signal

,

을 포함하는 도달지연시간을 구할 수 있다.By combining the calculation as shown in Table 1 above,

,

Can be obtained.

In the case of Table 1 above, the number of delay time arrival (TDOA) pairs is as follows.

은 마이크로폰의 개수이다.here,

Is the number of microphones.

The calculation of the arrival delay time by the virtual microphone has the advantage of improving the accuracy by increasing the number of combinations of the virtual sensors, but it has an effect of improving the spatial position estimation performance by being extended to the three-dimensional array. Since the planar array has a large positioning error with respect to the height direction, it constitutes a three-dimensional array, which results in an error reduction effect on the position. The virtual sensor (i.e., the virtual microphone) is possible when the reflected sound wave signal is divided by the cepstrum method and the delay time of the reflected signal is measured. That is, the environment of acoustic reflection by the ground should be well prepared.

와 지면 반사 음파 신호의 개수

에 의해서 위치 추정 계산에 이용되는 도달지연시간 쌍의 개수는 다음식과 같다.Since all surface acoustic wave signals are not measured in all microphones, they can be selectively applied and the number of microphones

And the number of ground reflection acoustic wave signals

The number of arrival delay time pairs used in the position estimation calculation is given by the following equation.

는 지면 반사 음파 신호의 개수이고,

은 마이크로폰의 개수이다.here,

Is the number of surface-reflected sound wave signals,

Is the number of microphones.

Therefore, the number of TDOA pairs can be increased to contribute to the improvement of the accuracy. Further, the two-dimensional array can be configured as a three-dimensional stereoscopic array.

FIG. 6 is a flowchart illustrating a process of estimating a position using a ground reflection effect based TDOA (Time Difference of Arrival) technique according to an embodiment of the present invention. 6, the signal acquisition unit 110 of FIG. 1 acquires the sound signal of the sound source using the microphone array 10 including a plurality of microphones (step S610) Generates a plurality of virtual sensors corresponding to the plurality of microphones (step S620).

Then, the sensor pair combining unit 130 combines the plurality of microphones and the plurality of virtual sensors into each pair (step S630).

Thereafter, the delay time calculation unit 140 calculates a time delay between the direct sound signal and the surface-reflected sound signal by using the direct sound signal directly transmitted by the combination and the surface-reflected sound signal transmitted through the ground reflection, The time delay between the direct sound wave signal and the surface reflected sound wave signal is used to generate arrival delay time simultaneous equations information (step S640).

Finally, the position estimating unit 150 estimates the final position information of the sound source using the arrival delay time simultaneous equations information (step S650).

The terms " part, " and the like, as described in the specification, may be embodied in hardware, software, or a combination thereof. (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microprocessor, and the like, which are designed to perform the above- , Other electronic units, or a combination thereof. In software implementation, it may be implemented as a module that performs the above-described functions. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

10: microphone array
100: sound source position estimating device
110: signal acquisition unit 120: virtual sensor generation unit
130: sensor pair combining unit 140: delay time calculating unit
150: Location State

Claims (8)

A signal acquiring unit acquiring an acoustic signal of a sound source from a microphone array composed of a plurality of microphones;
A virtual sensor generating unit for generating a plurality of virtual sensors corresponding to the plurality of microphones;
A sensor pair combining unit for combining the plurality of microphones and the plurality of virtual sensors into each pair;
Generating a pair of delay time relationship pairs by calculating a time delay between the direct sound wave signal and the ground surface reflected sound wave signal using the direct sound wave signal directly transmitted by the combination and the surface reflected sound wave signal transmitted by ground reflection, A delay time calculation unit for generating arrival delay time simultaneous equation information for the plurality of microphones and the plurality of virtual sensors from the time relation pair combination; And
And a position state part estimating final position information of the sound source using the arrival delay time simultaneous equations information,
Wherein the plurality of virtual sensors are configured such that coordinate information of the plurality of microphones at a predetermined height above the ground is symmetric to the ground,
The coordinate information of the plurality of microphones is determined by a position on the two-dimensional plane of the plurality of microphones and a height of the microphones on the ground,
The time delay between the acoustic signals is calculated from a cross-correlation function for a pair of microphones through a cepstrum,
Wherein the final position information is sound source position information in a three-dimensional space. 2. The sound source position estimating method according to claim 1, wherein the final position information is sound source position information in a three-dimensional space.
delete delete delete delete The method according to claim 1,
Wherein the final position information of the sound source is a simultaneous equations solution of the simultaneous equations information using a least squares method, and the sound source position estimating device using the delay time arrival technique based on the sound waves reflected directly on the ground and the sound wave reflected on the ground .
The method according to claim 1,
The time delay between the direct sound wave signal and the ground-

(here,

The

Lt; / RTI > represents the power capstrum function of the signal measured at < RTI ID =

Represents the i-th microphone position,

, Wherein the FFT is a fast Fourier transform, the IFFT is an inverse fast Fourier transform, and x (t) is a time function of an x coordinate. An apparatus for estimating a sound source position using a delay time arrival technique based on sound waves directly propagated in a sound source and sound waves reflected on the ground.
Obtaining a sound signal of a sound source using a microphone array having a plurality of microphones;
The virtual sensor generating unit generating a plurality of virtual sensors corresponding to the plurality of microphones;
Combining the sensor pair combination with the plurality of microphones and the plurality of virtual sensors in each pair;
Calculating a delay time between the direct sound wave signal and the surface-reflected sound wave signal by using the direct sound wave signal transmitted directly by the combination and the surface-reflected sound wave signal transmitted by ground reflection;
Wherein the delay time calculation unit generates a delay time relationship pair combination using the time delay between the direct sound wave signal and the ground surface reflected sound wave signal and calculates a delay time relation pair combination from the delay time relationship pair combination to the arrival delay of the plurality of microphones and the plurality of virtual sensors Generating time series equation information; And
Estimating a final position information of the sound source using the arrival delay time simultaneous equations information,
Wherein the plurality of virtual sensors are configured such that coordinate information of the plurality of microphones at a predetermined height above the ground is symmetric to the ground,
The coordinate information of the plurality of microphones is determined by a position on the two-dimensional plane of the plurality of microphones and a height of the microphones on the ground,
The time delay between the acoustic signals is calculated from a cross-correlation function for a pair of microphones through a cepstrum,
The final position information is information on the sound source position in the three-dimensional space A method for estimating a sound source location using a delay time arrival technique based on sound waves propagated directly from a sound source and sound waves reflected on the ground.

Images