阅读说明：本技术 气体泄漏位置三维定位方法、定位系统 (Three-dimensional positioning method and positioning system for gas leakage position ) 是由 李磊 王生会 李丰 田申 高杨 乔莹莹 单崇新 于 2021-08-31 设计创作，主要内容包括：气体泄漏位置三维定位方法,包括：建立基于基尔霍夫衍射远场声全息理论的声场模型；在测量平面获取泄漏源声场信息；处理获取的声场信息,得到泄漏源声场的声全息数据；利用声场模型和声全息数据,确定泄漏源的三维位置信息。气体泄漏位置三维定位方法能够获得更准确的声场信息,进而能够引入深度信息实现泄漏源的三维检测效果展示；通过构建基于基尔霍夫衍射理论的远场声全息模型,能够实现较大距离泄漏源的声场定位；利用虚拟相控阵列技术,在气体泄漏检测与定位中降低了系统成本和复杂度,提高了泄漏源检测精度和定位精度,在气体泄漏位置的准确定位方面具有巨大实用价值和工业应用潜力。(The three-dimensional positioning method for the gas leakage position comprises the following steps: establishing a sound field model based on kirchhoff diffraction far-field acoustic holography theory; acquiring leakage source sound field information on a measurement plane; processing the obtained sound field information to obtain acoustic holographic data of the sound field of the leakage source; and determining three-dimensional position information of the leakage source by using the sound field model and the acoustic holographic data. The three-dimensional positioning method for the gas leakage position can obtain more accurate sound field information, and further can introduce depth information to realize the three-dimensional detection effect display of a leakage source; by constructing a far-field acoustic holographic model based on the kirchhoff diffraction theory, the sound field positioning of a leakage source with a larger distance can be realized; by utilizing the virtual phased array technology, the system cost and complexity are reduced in gas leakage detection and positioning, the detection precision and the positioning precision of a leakage source are improved, and the method has great practical value and industrial application potential in the aspect of accurate positioning of a gas leakage position.)

1. The three-dimensional positioning method for the gas leakage position is characterized by comprising the following steps:

establishing a sound field model based on kirchhoff diffraction far-field acoustic holography theory;

acquiring leakage source sound field information on a measurement plane;

processing the obtained sound field information to obtain acoustic holographic data of the sound field of the leakage source;

and determining three-dimensional position information of the leakage source by using the sound field model and the acoustic holographic data.

2. The method for three-dimensional localization of a gas leakage position according to claim 1, wherein the obtaining of the sound field information of the leakage source at the measurement plane specifically comprises:

forming a virtual phased sensor array with equal array element spacing on a measurement plane according to a preset array rule by using an ultrasonic sensor, wherein the ultrasonic sensor comprises at least one reference sensor and at least one scanning sensor;

and acquiring sound field information of each array element position of the virtual phased sensor array one by using the scanning sensor, and synchronously acquiring the sound field information of the position of the reference sensor.

3. The gas leak position three-dimensional positioning method according to claim 2, wherein the processing the acquired sound field information includes:

and processing the sound field information obtained by the scanning sensor and the reference sensor by using a cross-power spectrum algorithm, eliminating the consistency of the scanning time interval reaching the acquisition time, and obtaining the acoustic holographic data of the leakage source measuring plane.

4. The three-dimensional positioning method for the gas leakage position according to claim 3, wherein the sound field model has the expression:

wherein, U (epsilon, eta) represents the sound pressure distribution of the leakage source plane and is defined as a space wave function h (x, y), and M, N is the row number and the column number of the virtual phased sensor array (M) N; h is^*(x, y) is a conjugate function of a space wave function h (x, y) and contains holographic information of the m-th row and n-th column positions of the virtual phased sensor array; r is_mnThe distance between the position of the mth row and the nth column of the virtual phased sensor array and the leakage source is shown; Δ x Δ y is the coverage area of the mth row and nth column of sensors of the virtual phased sensor array; c is a holographic constant; z is a radical of₀Is the vertical distance of the leakage source to the measurement plane;is a complex variable function; k is the wave number; m is less than or equal to M, and N is less than or equal to N.

5. The three-dimensional positioning method for the gas leakage position according to claim 3, wherein the processing the acquired sound field information specifically comprises:

information x to reference sensor_r(t) and information x of the ith scanning sensor_i(t) performing Fourier transform to obtain the following expression:

wherein the content of the first and second substances,andrespectively represent x_r(t) and x_i(t) Fourier transform, e^-j2πftIs a complex variable function;

the following expression is further obtained:

x_i(t) and x_rThe cross-power spectrum of (t) is expressed as:

wherein the content of the first and second substances,is x_r(t) the conjugate spectrum of the (t),is a complex variable function;

phase difference between signal collected by ith scanning sensor and reference signal collected by reference sensor simultaneouslyExpressed as:

wherein Im [ R (f) ] represents the imaginary part of R (f), and Re [ R (f) ] represents the real part of R (f);

the signal collected by the first scanning sensor in the virtual phased sensor array is X₁(t), then, the signal X collected by the ith sensor_i(t) is expressed as:

wherein the content of the first and second substances,is X₁(t) a phase difference with a simultaneously received reference signal,is X_i(t) a phase difference with a simultaneously received reference signal,is a complex variable function.

6. The method of claim 1, wherein the determining three-dimensional location information of a leak source comprises:

performing leakage source sound field reconstruction calculation by using the acoustic holographic data and the acoustic field model, and displaying a calculation result as leakage source image information;

performing sound field reconstruction calculation for multiple times at different distances at set reconstruction distance intervals, and displaying image information of multiple leakage sources;

and determining leakage source position information corresponding to the leakage source image information with the highest definition as leakage source three-dimensional position information.

7. The method of claim 6, wherein the leak source image information comprises two-dimensional image information or three-dimensional image information.

8. The method for three-dimensional positioning of the gas leakage position according to claim 2, wherein the preset array rules comprise array element spacing, array element number and array shape.

9. The method of claim 1, wherein the determining three-dimensional location information of a leak source comprises holographically displaying the leak source location.

10. The gas leakage position three-dimensional positioning system for realizing the gas leakage position three-dimensional positioning method according to any one of claims 1 to 8, comprising:

the information acquisition assembly comprises at least one scanning sensor and at least one reference sensor and is used for acquiring sound field information of a leakage source on a measurement plane;

a linear moving platform for controlling the scanning sensor and the reference sensor to form a virtual phased array;

and the data processing component is embedded with a sound field model, is used for transmitting and processing the sound field information, acquires sound holographic data, and calculates and determines the three-dimensional position information of the leakage source by using the established sound field model and the processed sound holographic data.

Technical Field

The application belongs to the technical field of gas detection, and particularly relates to a three-dimensional positioning method and a three-dimensional positioning system for a gas leakage position.

Background

The transport and storage of gases is ubiquitous in people's industrial applications and everyday life. However, during the use of gas pipelines or storage facilities, leakage often occurs during the transportation or storage of compressed gas due to damage by itself or other human factors. In many industrial applications, these compressed gases are often characterized by flammability, explosiveness, or corrosive toxicity, and once a leakage accident occurs, they will cause serious environmental pollution, huge resource waste, and major safety accidents. The ability to quickly and accurately locate the gas leak location is critical to preventing gas transportation or storage accidents.

At present, a one-dimensional detection method for a gas leakage source can detect and position leakage holes in pipelines and containers. For example, patent CN109813501A discloses a method, device and system for measuring the leakage position of a gas pipeline, which utilize a small number of sensors to ensure the uniformity of data acquisition, improve the measurement accuracy, and improve the effectiveness of positioning the leakage position of the gas pipeline; however, in general, the environment where gas leakage actually occurs is very complicated, and due to the influence of external noise interference and the complicated mechanism that the reflected wave and stress wave of the leakage acoustic signal propagate in the pipeline or the storage tool, the accuracy of the one-dimensional detection mode of the gas leakage source is greatly limited when the leakage hole of the pipeline is identified and positioned.

The two-dimensional detection method for the gas leakage source is still in an initial research stage of adopting a linear array or other small arrays at present, and the imaging resolution and the positioning accuracy are low. On the other hand, because the depth information (i.e., distance information) of the gas leakage source cannot be effectively estimated by such methods, a three-dimensional positioning method suitable for the gas leakage source is still lacked at present, and the three-dimensional positioning of the gas leakage source cannot be realized.

Disclosure of Invention

In view of the above, in one aspect, some embodiments disclose a method for three-dimensionally locating a gas leakage position, the method comprising:

establishing a sound field model based on kirchhoff diffraction far-field acoustic holography theory;

acquiring leakage source sound field information on a measurement plane;

processing the obtained sound field information to obtain acoustic holographic data of the sound field of the leakage source;

and determining three-dimensional position information of the leakage source by using the sound field model and the acoustic holographic data.

Further, the three-dimensional positioning method for a gas leakage position disclosed in some embodiments specifically includes, in a measurement plane, obtaining sound field information of a leakage source:

forming a virtual phased sensor array with equal array element spacing on a measurement plane according to a preset array rule by using an ultrasonic sensor, wherein the ultrasonic sensor comprises at least one reference sensor and at least one scanning sensor;

and acquiring sound field information of each array element position of the virtual phased sensor array one by using the scanning sensor, and synchronously acquiring the sound field information of the position of the reference sensor.

Some embodiments disclose a method for three-dimensionally locating a gas leakage position, wherein the processing of the acquired sound field information comprises:

and processing sound field information obtained by the scanning sensor and the reference sensor by using a cross-power spectrum algorithm, eliminating scanning time intervals, achieving the consistency of acquisition time, and obtaining acoustic holographic data of a leakage source measuring plane.

Some embodiments disclose a method for three-dimensionally positioning a gas leakage position, wherein an expression of a sound field model is as follows:

wherein, U (∈, η)) A sound pressure distribution representing a leakage source plane, defined as a spatial wave function h (x, y), M, N being the number of rows and columns of the virtual phased sensor array (M × N); h (x, y) is a conjugate function of a space wave function h (x, y) and contains acoustic holographic information of the m-th row and n-th column positions of the virtual phased sensor array; r is_mnThe distance between the position of the mth row and the nth column of the virtual phased sensor array and the leakage source is shown; Δ x Δ y is the coverage area of the mth row and nth column of sensors of the virtual phased sensor array; c is a holographic constant; z is a radical of₀Is the vertical distance of the leakage source to the measurement plane;is a complex variable function; k is the wave number; m is less than or equal to M, and N is less than or equal to N.

Some embodiments disclose a method for three-dimensionally positioning a gas leakage position, wherein the processing of the acquired sound field information specifically includes:

information x to reference sensor_r(t) and information x of the ith scanning sensor_i(t) performing Fourier transform to obtain the following expression:

wherein the content of the first and second substances,andrespectively represent x_r(t) and x_i(t) Fourier transform, e^-j2πftIs a complex variable function;

the following expression is further obtained:

x_i(t) and x_rThe cross-power spectrum of (t) can be expressed as:

wherein the content of the first and second substances,is x_r(t) the conjugate spectrum of the (t),is a complex variable function;

phase difference between signal collected by ith scanning sensor and reference signal collected by reference sensor simultaneouslyExpressed as:

wherein Im [ R (f) ] represents the imaginary part of R (f), and Re [ R (f) ] represents the real part of R (f);

the signal collected by the first scanning sensor in the virtual phased sensor array is X₁(t), then, the signal X collected by the ith sensor_i(t) is expressed as:

wherein the content of the first and second substances,is X₁(t) a phase difference with a simultaneously received reference signal,is X_i(t) a phase difference with a simultaneously received reference signal,is a complex variable function。

Some embodiments disclose a method for three-dimensional localization of a gas leak location, wherein determining three-dimensional location information of a leak source comprises:

performing leakage source sound field reconstruction calculation by using the acoustic holographic data and the acoustic field model, and displaying a calculation result as leakage source image information;

performing multiple times of sound field reconstruction calculation on different distances at set reconstruction distance intervals, and displaying image information of a plurality of leakage sources;

and determining leakage source position information corresponding to the leakage source image information with the highest definition as leakage source three-dimensional position information.

Some embodiments disclose the method for three-dimensional positioning of the gas leakage position, wherein the leakage source image information comprises two-dimensional image information or three-dimensional image information.

In some embodiments of the disclosed three-dimensional positioning method for gas leakage positions, the preset array rules include array element spacing, array element number and array shape.

Some embodiments disclose a method for three-dimensional localization of a gas leak location, wherein determining three-dimensional location information of a leak source comprises holographically displaying a leak source location.

In another aspect, some embodiments disclose a gas leak location three-dimensional positioning system for implementing the gas leak location three-dimensional positioning method disclosed in some embodiments, the three-dimensional positioning system comprising:

the information acquisition assembly comprises at least one scanning sensor and at least one reference sensor and is used for acquiring sound field information of a leakage source on a measurement plane;

the linear moving platform is used for controlling the scanning sensor and the reference sensor to form a virtual phased array;

the data processing component is embedded with a sound field model, is used for transmitting and processing sound field information, acquiring sound holographic data, establishing the sound field model, and calculating and determining the three-dimensional position information of the leakage source by using the established sound field model and the processed sound holographic data.

The three-dimensional positioning method for the gas leakage position, disclosed by the embodiment of the application, can obtain more accurate sound field information, and further can introduce depth information to realize the three-dimensional detection effect display of a leakage source; by constructing a far-field acoustic holographic model based on the kirchhoff diffraction theory, the sound field positioning of a leakage source with a larger distance can be realized; by utilizing the virtual phased array technology, the system cost and complexity are reduced in gas leakage detection and positioning, the detection precision and the positioning precision of a leakage source are improved, and the method has great practical value and industrial application potential in the aspect of accurate positioning of a gas leakage position.

Drawings

FIG. 1 is a schematic diagram of the principle of the diffraction acoustic holography method

FIG. 2 is a schematic diagram of sound field information collection principle

FIG. 3 is a schematic diagram of a gas leakage three-dimensional positioning system

FIG. 4 is a schematic view of a two-dimensional plane projection of a three-dimensional positioning result of gas leakage

FIG. 5 is a schematic diagram of two-dimensional plane projection and three-dimensional projection of three-dimensional positioning result of gas leakage

FIG. 6 is a diagram of the three-dimensional positioning and detecting effect of gas leakage

Reference numerals

1 reference sensor 2 scanning sensor

3-letter data processing component 4 linear moving platform

12 virtual phased array 100 leakage source

101 virtual array element x₁Transverse spacing

y₁Longitudinal spacing 102 air compressor

103 nozzle 104 nozzle sound source hologram

105 nozzle sound source holographic image enlarged view

Detailed Description

The word "embodiment" as used herein, is not necessarily to be construed as preferred or advantageous over other embodiments, including any embodiment illustrated as "exemplary". Performance index tests in the examples of this application, unless otherwise indicated, were performed using routine experimentation in the art. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; other test methods and techniques not specifically mentioned in the present application are those commonly employed by those of ordinary skill in the art.

The terms "substantially" and "about" are used herein to describe small fluctuations. For example, they may mean less than or equal to ± 5%, such as less than or equal to ± 2%, such as less than or equal to ± 1%, such as less than or equal to ± 0.5%, such as less than or equal to ± 0.2%, such as less than or equal to ± 0.1%, such as less than or equal to ± 0.05%. Numerical data represented or presented herein in a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of "1 to 5%" should be interpreted to include not only the explicitly recited values of 1% to 5%, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values, such as 2%, 3.5%, and 4%, and sub-ranges, such as 1% to 3%, 2% to 4%, and 3% to 5%, etc. This principle applies equally to ranges reciting only one numerical value. Moreover, such an interpretation applies regardless of the breadth of the range or the characteristics being described. The sensor mentioned herein generally refers to a sensor capable of collecting sound signals, such as an ultrasonic sensor.

In this document, including the claims, conjunctions such as "comprising," including, "" carrying, "" having, "" containing, "" involving, "" containing, "and the like are understood to be open-ended, i.e., to mean" including but not limited to. The conjunctions "consisting of … …" and "consisting of … …" are closed conjunctions.

In the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present application may be practiced without some of these specific details. In the examples, some methods, means, instruments, apparatuses, etc. known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

On the premise of no conflict, the technical features disclosed in the embodiments of the present application may be combined arbitrarily, and the obtained technical solution belongs to the content disclosed in the embodiments of the present application.

In some embodiments, a method for three-dimensional localization of a gas leak location comprises: establishing a sound field model based on a kirchhoff diffraction far-field acoustic holography theory, acquiring leakage source sound field information on a measuring plane, processing the acquired sound field information to obtain acoustic holography data of a leakage source sound field, and determining three-dimensional position information of a leakage source by using the sound field model and the acoustic holography data. The method comprises two stages of establishing a sound field model based on a kirchhoff far-field holographic theory and independently obtaining the sound field information of the leakage source, wherein the three-dimensional positioning method does not limit the sequence in general. Unless the actual order of execution is indicated in the specific implementation or otherwise determined by context.

As an alternative embodiment, the obtaining of the sound field information of the leakage source on the measurement plane specifically includes: forming a virtual phased sensor array with equal array element spacing on a measurement plane according to a preset array rule by using an ultrasonic sensor, wherein the ultrasonic sensor comprises at least one reference sensor and at least one scanning sensor; and acquiring sound field information of each array element position of the virtual phased sensor array one by using the scanning sensor, and synchronously acquiring the sound field information of the position of the reference sensor by using the reference sensor.

As an alternative embodiment, processing the acquired sound field information includes: and processing sound field information obtained by the scanning sensors and the reference sensor by using a cross-power spectrum algorithm, eliminating scanning time intervals of different scanning sensors to obtain the consistency of acquisition time, and obtaining the acoustic holographic data of the leakage source measuring plane.

As an alternative embodiment, the sound field model expression is:

wherein, U (epsilon, eta) represents the sound pressure distribution of the leakage source plane and is defined as a space wave function h (x, y), and M, N is the row number and the column number of the virtual phased sensor array (M) N; h (x, y) is a holographic function and contains holographic information of the m-th row and n-th column positions of the virtual phased sensor array; r is_mnThe distance between the position of the mth row and the nth column of the virtual phased sensor array and the leakage source is shown; Δ x Δ y is the coverage area of the mth row and nth column of sensors of the virtual phased sensor array; c is a holographic constant; z is a radical of₀Is the vertical distance of the leakage source to the measurement plane;is a complex variable function; k is the wave number; m is less than or equal to M, and N is less than or equal to N.

Establishment of sound field model

In the acoustic holographic analysis of gas leakage sources, there are two important parallel planes in the acoustic field radiated by the target source: a sound source plane and a measurement plane, which are two parallel planes important in a planar acoustic holography method. With the far-field acoustic holographic model established, the sound fields of two spatially separated planes can be correlated by a projection operator, i.e. by knowing the field in one plane, the field in the other plane parallel thereto can be estimated numerically. Therefore, the radiation field of the sound source plane can be calculated from the measurement field measured at the measurement plane, and the leak position can be identified from the radiation field of the sound source plane.

The following exemplary description utilizes a linear model of pressure field propagation to construct a holographic representation of the sound field as a function of two-dimensional plane measurements.

The propagation of sound pressure waves P in a linear incompressible fluid can be expressed in helmholtz equation:

where u (P) is the complex amplitude of observation point P (x, y, z), k is the wavenumber, and is represented by the following formula:

where ω is the signal angular frequency, λ is the wavelength of the leakage signal, and c is the propagation velocity of the acoustic wave. It can be seen that the helmholtz equation is independent of time factors and describes a stable sound field that does not vary with time.

The classical infinity hoff diffraction formula is given by:

where U is the sound field distribution of the point P (x, y) in space, which can be defined as the spatial wave function h (x, y); n is the normal vector of the measurement plane; r is the modulus of the radius vector r, e^ikrRepresenting a complex variable function;

given h (x, y), the kirchhoff diffraction product formula can calculate the field at any point P in the direction of wave propagation in passive space. Using this property, the wavefield distribution at the next plane can be derived from the wavefield distribution at the known plane. For example, it can be realized by the following embodiments.

As shown in fig. 1, θ is an angle between a radius vector r and a normal vector n of a measurement plane, Σ is an infinite plane at a position of the measurement plane in space, and H is a finite measurement portion on the infinite plane, i.e., the measurement plane; r is a plane where a sound source point S (epsilon, eta) is located, and can be called a sound source plane, and epsilon and eta respectively represent coordinates on an x axis and a y axis.

The spatial wave function H (x, y) is subjected to conjugation processing to obtain H (x, y), so that a holographic function H (x, y) containing information of the conjugate wave of the measurement signal can be obtained, the conjugate wave continuously propagates, and a real image S converged at a sound source S (e, eta) is obtained₁Upper (S)₁Can be considered as a virtual sound source). The propagation of the conjugate wave is shown in fig. 1 (b).

The relationship between the normal vector n, the radius vector r, and the direction vector z of the z-axis is given by:

the hologram function H (x, y) can be expressed as:

H(x,y)＝U＝h*(x,y)e^jkz ……(6)

wherein h (x, y) is a conjugate representation of h (x, y), k is the wave number, e^jkzRepresenting a complex function.

By substituting formulae (4), (5), and (6) for formula (3), the sound pressure distribution in the sound source plane can be obtained:

the integral hologram plane xOy is infinite, but in actual measurement, continuous sound pressure points in the plane cannot be measured, and therefore, the sound pressure distribution equation should be discretized. For example, a virtual phased sensor array is arranged in the measurement plane, the array element sensors in the array represent discrete sound information measurement points, and the discretized sound pressure distribution formula is as follows:

wherein, U (epsilon, eta) represents the sound pressure distribution of the leakage source plane and is defined as a space wave function h (x, y), and M, N is the row number and the column number of the virtual phased sensor array (M) N; h (x, y) is a holographic function and contains holographic information of the m-th row and n-th column positions of the virtual phased sensor array; r is_mnThe distance between the position of the mth row and the nth column of the virtual phased sensor array and the leakage source is shown; Δ x Δ y is the coverage area of the mth row and nth column of sensors of the virtual phased sensor array; c is a holographic constant; z is a radical of₀Is to let outThe vertical distance from the drain source to the measurement plane;is a complex variable function; k is the wave number; m is less than or equal to M, and N is less than or equal to N.

The same procedure is repeated for each leakage source point, and the sound pressure distribution of the entire leakage source plane can be obtained.

Sound field information acquisition and processing

Constructing virtual phased arrays

As shown in fig. 2, a virtual phased array 12 is arranged in the sound field information measurement plane, the phased array includes M × N array elements as sound field information acquisition points, and an M × N virtual phased array is formed, where all the array elements are arranged at equal intervals, and the M × N acquisition points form a square virtual phased array 12; the leakage source 100 is arranged in a three-dimensional rectangular coordinate system space, a virtual phased array 12 is formed at a proper position on the right side of the leakage source 100, a fixed-position reference sensor 1 is arranged in the virtual phased array 12, a movable-position scanning sensor 2 is arranged at the same time, and the reference sensor 1 and the scanning sensor 2 are connected with a data processing component 3;

the scanning sensor 2 is used for acquiring sound field information of each acquisition point in the virtual phased array 12 one by one, and meanwhile, the reference sensor 1 is used for synchronously measuring the sound field information of the set position of the reference sensor; wherein the information collected by the reference sensor 1 is denoted x_r(t), the information collected by the scanning sensor 2 at the ith acquisition point is denoted as x_i(t) expressed as:

x_r(t)＝α₁s(t-τ_i-t_sr)+n_r(t)(i＝1,2,…n) ……(9)

x_i(t)＝α₂s(t-τ_i-t_si)+n_i(t)(i＝1,2,…n) ……(10)

wherein, s (t) is the collected sound field signal generated by the leakage source; alpha is alpha₁And alpha₂Is an attenuation factor; n is_r(t) and n_i(t) noise of the reference sensor and the scanning sensor, respectively; tau is_iIs the scanning time interval of the scanning sensor between the ith acquisition point and the (i-1) th acquisition point.

The time difference delta t between the time of the scanning sensor 2 for acquiring information at the ith acquisition point and the time of acquiring signals by the reference sensor 1 can be obtained_iComprises the following steps:

Δt_i＝t_sr-t_si(i＝1,2,…,n) ……(11)

as can be seen from the above formula,. DELTA.t_iDoes not include the scanning time interval tau_iDescription of τ_iIndependent of the scanning time interval. Therefore, the cross-power spectrum method can eliminate the scanning time interval of scanning sensors in the virtual phased array one by one, and a model which is the same as that of the traditional sensor array is obtained.

Sound field information processing

As an alternative embodiment, the processing the acquired sound field information by using the cross-power spectrum method specifically includes:

information x to reference sensor_r(t) and information x of scanning sensor at ith information acquisition point_i(t) performing Fourier transform to obtain the following expression:

wherein the content of the first and second substances,andrespectively represent x_r(t) and x_i(t) Fourier transform, e^-j2πftIs a complex variable function;

the following expression is further obtained:

x_i(t) and x_rThe cross-power spectrum of (t) can be expressed as:

wherein the content of the first and second substances,is x_r(t) the conjugate spectrum of the (t),is a complex variable function;

phase difference between signal collected by scanning sensor at ith information collecting point and reference signal collected by reference sensor at same timeExpressed as:

wherein Im [ R (f) ] represents the imaginary part of R (f), and Re [ R (f) ] represents the real part of R (f);

the signal collected by the scanning sensor at the first information collecting point in the virtual phased sensor array is X₁(t), then, signal X collected by the ith information collection point_i(t) is expressed as:

wherein the content of the first and second substances,is X₁(t) a phase difference with a simultaneously received reference signal,is X_i(t) phase with reference signal received simultaneouslyThe potential difference is measured by a potential difference measuring device,is a complex variable function.

By repeating the same procedure for each array element, holographic data similar to a conventional sensor array can be obtained. And (3) utilizing holographic data and combining an acoustic holographic method, and utilizing a sound field model to calculate the sound pressure distribution of the whole leakage source plane.

Some embodiments disclose a method for three-dimensional localization of a gas leak location, wherein determining three-dimensional location information of a leak source comprises:

performing leakage source reconstruction calculation by using the acoustic holographic data and the acoustic field model, and displaying a calculation result as leakage source image information;

carrying out reconstruction calculation for multiple times at set reconstruction distance intervals, and displaying image information of multiple leakage sources; the method comprises the steps of performing leakage source reconstruction in two directions of equal distance, distance increase and distance decrease on the basis of the distance calculated by first reconstruction, and displaying information of a plurality of leakage source images at different reconstruction distances;

and determining leakage source position information corresponding to the leakage source image information with the highest definition as leakage source three-dimensional position information. Generally, the sharpness of the image is the highest, which means that the focusing effect of the imaging process is the best.

As an alternative embodiment, the leakage source image information comprises two-dimensional image information or three-dimensional image information.

As an alternative embodiment, the preset array rule includes array element spacing, array element number and array shape. Generally, array element quantity and array element spacing can be reasonably set according to the specific conditions of the leakage source, such as measuring distance, measuring space and the like, and a reasonable array shape is set so as to meet the requirements of the measurement precision, the measurement efficiency and the like of the leakage source.

Some embodiments disclose a gas leakage position three-dimensional positioning system for implementing a gas leakage position three-dimensional positioning method, the three-dimensional positioning system including:

the information acquisition assembly comprises at least one scanning sensor and at least one reference sensor and is used for acquiring sound field information of a leakage source on a measurement plane; generally, the setting of a virtual phased array and the sound field information acquisition can be realized by arranging a reference sensor and a scanning sensor; a plurality of scanning sensors and reference sensors can be arranged to realize the setting of the phased array and the sound field information acquisition, generally, the number of the sensors is far smaller than that of the array elements of the virtual phased array, and the advantages of the virtual phased array can be effectively exerted;

a linear moving platform for controlling the scanning sensor and the reference sensor to form a virtual phased array; the general linear moving platform can accurately control the positions and the movement of the scanning sensor and the reference sensor, control the sensor to move in the virtual phased array according to a set rule and acquire sound field information of each phased array element position;

and the data processing component is used for transmitting and processing the sound field information, acquiring acoustic holographic data, establishing a sound field model, and calculating and determining the three-dimensional position information of the leakage source by using the established sound field model and the processed acoustic holographic data. Generally, an established sound field model is embedded or implanted in the data processing assembly, for example, the sound field model can be implanted in an upper computer; generally, the data processing component comprises a data acquisition component, including a multi-channel data acquisition card, an acquisition program panel and the like, and can transmit information acquired by a sensor to an upper computer; the upper computer is used for controlling the sensor and the linear moving platform to form a virtual phased array, collecting sound field information and controlling a data collecting component; and further, the upper computer processes data according to the established far-field acoustic holographic model and displays a three-dimensional positioning result.

Construction of three-dimensional positioning system for gas leakage

As shown in FIG. 3, a reference sensor 1 and a scanning sensor 2 are provided, the scanning sensor 2 and the reference sensor 1 are controlled by a linear moving platform 4, the reference sensor 1 and the scanning sensor 2 are arranged in a three-dimensional rectangular coordinate system XYZ space, a virtual phased array 12 is arranged in a monitoring plane XOY, the virtual phased array 12 comprises a plurality of virtual array elements 101 arranged at equal intervals, and the virtual array elements 101 are transversely spacedIs x₁Longitudinal interval of y₁(ii) a A data processing component 3 is arranged, connected with the scanning sensor 2 and the reference sensor 1 and connected with the linear moving platform 4; the data processing component 3 generally comprises an analog input channel, an ADC chip, a PFGA chip, a PCI controller, a memory, etc., and may further comprise a precision reference source, a calibration circuit, etc.;

the linear moving platform 4 controls the scanning sensor 2 to move in a monitoring plane, and sound field information can be acquired at the position of each virtual array element 101 one by one; the reference sensor 1 is arranged at the position of an origin O of the coordinate system and synchronously acquires sound field information of the position with the scanning sensor 2;

in the process of acquiring data by the gas leakage three-dimensional positioning system, the reference sensor 1 is utilized to acquire sound field information of the position of an origin O of a coordinate system, the scanning sensor 2 sequentially acquires the sound field information of the positions of the virtual array elements 101 one by one, and the reference sensor 1 synchronously acquires the sound field information of the position of the origin of the coordinate system when the scanning sensor 2 acquires the sound field information of the position of each virtual array element 101; sound field information collected by the reference sensor 1 and the scanning sensor 2 is input into the data processing component 3, is transmitted to an information storage component of the data processing component 3 through the analog input channel I and the analog input channel II for storage and is subjected to cross power spectrum calculation through the information processing component, scanning time intervals are eliminated, and holographic data are obtained; according to the established acoustic holographic model and the obtained acoustic holographic data, the sound pressure distribution of the sound field of the leakage source 100 is calculated, the depth information of the leakage source is obtained, and three-dimensional positioning is achieved.

Specifically, an air compressor is used as a target air source, the target air source is sprayed out from a nozzle to form a leakage source, the leakage source is arranged in an XYZ space of a three-dimensional rectangular coordinate system, and a transverse distance x is set₁Is 3mm, and has a longitudinal spacing y₁Setting to form a virtual phased array containing 60 multiplied by 60 virtual array elements for 3mm, setting the distance between adjacent sensors to be smaller than half wavelength of sound wave model to ensure that the limitation of space sampling theorem is met, recording leakage sound field signals by using a full-digital double-channel recorder at the frequency of 1MHz of sampling rate, and positioning a measuring plane at a distance z from a sound source_h0.6m and the measuring plane is a square plane with a side length of 18 cm. MeasuringAnd after the measurement of the leakage sound field data is finished on the measuring plane, carrying out three-dimensional detection and imaging on the leakage source sound field through post-processing.

And constructing sound fields at a plurality of distances by using sound field information and a sound field model obtained at a measuring plane 0.6m away from the leakage source, and performing three-dimensional imaging, wherein the distance interval of sound field reconstruction is 0.15m each time. As a result, as shown in fig. 4, the distance z represents the distance from the measurement plane, and the clearer the boundary of the leakage source image in the graph indicates that the leakage sound field is stronger (in actual operation, the leakage source image is displayed in red, and the redder the color indicates that the leakage sound field is stronger), so that the position where the leakage sound field is strongest can be visually judged as the leakage source.

In fig. 4, the sound field reconstruction is performed every 0.15m, and it can be seen that the reconstructed image gradually converges as the reconstruction distance z increases; when the reconstruction distance z exceeds the actual distance by 0.6m, the reconstructed image gradually diverges, and the resolution gradually decreases until losing significance. It can be seen that the leakage source can only be reconstructed well if the reconstruction distance z is equal to the actual distance. In contrast, images located at other distances show strong artifacts, and the leakage source is not well reconstructed. The leakage sound field reconstruction is repeatedly carried out at different depths, so that the effective estimation of the depth information of the leakage source is achieved, and the three-dimensional positioning of the leakage source is realized. It can be determined that the location of the leakage source is z 0.6 m.

In fig. 5, the results of the localization of the leakage source at distances of 0.3m, 0.6m and 1.2m are shown, including two-dimensional planar projection imaging and corresponding three-dimensional imaging.

Fig. 6 is a three-dimensional positioning detection effect diagram of gas leakage, which directly shows the positioning effect of an actual test site. In fig. 6, an air compressor 102 is connected to a nozzle 103 to form a gas leakage source, after a measurement plane completes measurement of leakage sound field data, the obtained data is processed and subjected to three-dimensional detection and imaging, a nozzle sound source hologram 104 is directly displayed at the position of the nozzle gas leakage source, and a nozzle sound source hologram enlargement 105 is an effect of enlarging and displaying the nozzle sound source hologram 104.

Reliability test of positioning system

In order to verify the stability and reliability of the three-dimensional positioning system, a plurality of groups of repeated implementation are recorded on the positioning system, a leakage source is located at 0.6m, and the test result is subjected to error analysis, wherein the result is shown in table 1.

TABLE 1 three-dimensional positioning System results and analysis

The relative error (%) in the positioning in the x and y directions is defined as the ratio of the difference between the estimated and actual position of the leakage source to the reconstructed plane dimensions. It can be seen from table 1 that the positioning error of this method in the x and y directions is about 5%.

In order to analyze the positioning accuracy of the method in the z direction, the sound field in front of the measurement plane is defined as a rectangular solid space of 0.6 × 1.2m and is discretized into a 60 × 60 × 24 grid (divided into 24 grids in the z direction). It can be seen from table 1 that the positioning error in the z-direction is about 2-3 grids. The error statistics shows that the error performance of the positioning system can meet most of actual engineering requirements, and the positioning effect is stable and reliable.

Generally, as the distance of the gas leakage source increases, the resolution of the final image of the leakage source decreases slightly; this typically occurs in connection with negative influences such as noise, acoustic reflections, etc. due to an increased detection distance.

The three-dimensional positioning method for the gas leakage position, disclosed by the embodiment of the application, can obtain more accurate sound field information, and further can introduce depth information to realize the three-dimensional detection effect display of a leakage source; by constructing an acoustic holographic model based on the kirchhoff diffraction theory, the sound field positioning of a leakage source with a larger distance can be realized; by utilizing the virtual phased array technology, the system cost and complexity are reduced in gas leakage detection and positioning, the detection precision and the positioning precision of a leakage source are improved, and the method has great practical value and industrial application potential in the aspect of accurate positioning of a gas leakage position.

The technical solutions and the technical details disclosed in the embodiments of the present application are only examples to illustrate the inventive concept of the present application, and do not constitute a limitation on the technical solutions of the present application, and all the conventional changes, substitutions, combinations, and the like made to the technical details disclosed in the present application have the same inventive concept as the present application and are within the protection scope of the claims of the present application.