A pipeline guided wave signal processing method and system

Abstract

The present application relates to the technical field of signal processing, and particularly relates to a pipeline guided wave signal processing method and system. The method comprises the following steps: acquiring multi-channel ultrasonic guided wave signals through a sensor array arranged circumferentially around a pipeline, and converting the signals into a frequency domain response matrix; calculating a circumferential amplitude distortion degree based on the amplitude distribution of the power spectrum of each channel; constructing a modal coupling matrix in combination with the circumferential amplitude distortion degree and an ideal pipeline theoretical wave number; generating a modal projection matrix by correcting a standard orthogonal modal matrix; and decomposing the frequency domain response matrix by using the projection matrix to separate a structure echo component and a defect signal component. The present application more accurately evaluates the influence of geometric defects such as ellipticity deviation, accurately models the energy exchange between modes and corrects the orthogonality assumption, suppresses modal energy leakage, improves the decomposition accuracy, effectively separates signals, solves the interference of coherent noise, and improves the accuracy and reliability of pipeline defect detection.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to a method and system for processing guided wave signals in a pipeline. Background Technology

[0002] In the energy and chemical industries, health monitoring of long-distance pipelines is crucial. Ultrasonic guided wave detection technology, due to its advantages such as long detection distance and high efficiency, is used for the rapid screening of pipeline corrosion and cracks.

[0003] In existing ultrasonic guided wave testing technologies for pipelines, Normal Mode Expansion (NME) is a mainstream signal processing method for coherent noise interference generated by structural features such as welds and flanges. Based on pipeline waveguide theory, NME decomposes the received complex guided wave signal into a linear superposition of a series of orthogonal characteristic modes. Ideally, due to the strict orthogonality between different modes, such as longitudinal wave modes and bending wave modes, NME can accurately calculate the reflection coefficients of each pipeline mode. Based on the physical law that weld reflections are mainly concentrated in axisymmetric modes while defect reflections excite non-axisymmetric modes, NME can suppress structural noise and extract defect signals.

[0004] However, existing NME technology is mainly limited by the ideal pipe waveguide assumption, which assumes that the pipe is a cylinder with an absolutely regular cross-section and absolutely uniform material. But in actual industrial scenarios, pipes often have geometric non-uniformities in the weld area, such as ellipticity deviation, uneven wall thickness, or eccentricity of the anti-corrosion layer. Geometric non-uniformity directly violates the mathematical condition of modal orthogonality. When using NME technology based on an ideal model to process actual non-uniform pipe signals, mathematical energy leakage or spurious coupling will occur between different pipe modes. That is, the axisymmetric mode energy that originally belongs to the weld reflection is incorrectly projected into the non-axisymmetric mode component, which makes it impossible to completely eliminate the weld-related noise, and may even produce false defect artifacts. This affects the reliability and effectiveness of pipe guided wave signal processing and reduces the accuracy of defect detection. Summary of the Invention

[0005] To address the problem that existing NME technology suffers from modal orthogonality failure due to pipeline geometric non-uniformity, resulting in large signal decomposition errors and numerous false artifacts, which in turn affect the reliability and effectiveness of pipeline guided wave signal processing and reduce the accuracy of defect detection, this invention provides a pipeline guided wave signal processing method and system.

[0006] In a first aspect, the present invention provides a pipeline guided wave signal processing method, which adopts the following technical solution:

[0007] A pipeline guided wave signal processing method includes: acquiring multi-channel ultrasonic guided wave signals through a sensor array arranged around the circumference of the pipeline, and converting the multi-channel ultrasonic guided wave signals into a frequency domain response matrix; calculating the circumferential amplitude distortion degree, which characterizes the circumferential non-uniformity of the pipeline, based on the distribution characteristics of the power spectrum amplitude of each channel in the frequency domain response matrix; constructing a mode coupling matrix for evaluating the energy exchange relationship between modes based on the circumferential amplitude distortion degree and the theoretical wavenumber of each pipeline mode under ideal pipeline conditions; correcting the orthogonal mode matrix obtained based on pipeline waveguide theory using the mode coupling matrix to generate a mode projection matrix containing decoupling logic; performing mode decomposition on the frequency domain response matrix using the mode projection matrix to obtain a corrected mode coefficient vector, and separating the structural echo component for identifying weld structures in the pipeline and the defect signal component for identifying defects in the pipeline from the corrected mode coefficient vector, thereby realizing the processing of pipeline guided wave signals.

[0008] This invention assesses the geometric non-uniformity of pipelines by calculating circumferential amplitude distortion, more accurately reflecting the impact of geometric defects such as ellipticity deviation and wall thickness inhomogeneity on guided wave propagation, and providing a reliable basis for non-uniformity assessment in the construction of modal coupling matrices. By constructing modal coupling matrices, it achieves accurate modeling of the energy exchange relationship between modes in actual pipelines, effectively correcting the orthogonality assumption under the ideal model and accurately describing the modal coupling characteristics in non-uniform pipelines. By modifying the standard orthogonal modal matrix to generate the modal projection matrix, it achieves adaptive optimization of the modal decomposition process, effectively suppressing intermodal energy leakage and improving the accuracy of modal decomposition. Based on the separation of structural echoes and defect signals from the corrected modal coefficient vectors, it effectively solves the problem of coherent noise interference and improves the accuracy and reliability of pipeline defect detection.

[0009] Furthermore, the conversion of multi-channel ultrasonic guided wave signals into a frequency domain response matrix includes: truncating and performing fast Fourier transform on the time domain signal of each channel, calculating the power spectral density, and constructing the frequency domain response matrix at each frequency within the current analysis period.

[0010] Furthermore, the circumferential amplitude distortion satisfies:

[0011] In the formula, Frequency within the current analysis period Circumferential amplitude distortion at the location, The total number of channels. For the current analysis period, the [number]th Each channel at frequency The power spectral amplitude at that point For all channels in the current analysis period at frequency The mean of the power spectrum amplitude at that location, For all channels in the current analysis period at frequency The standard deviation of the power spectrum amplitude at that point It is the natural logarithm function. It is the absolute value symbol.

[0012] This invention achieves a scientific assessment of circumferential amplitude distortion by constructing a product model that includes relative deviation and logarithmic coefficient of variation. The relative deviation term accurately reflects the degree of deviation of the power spectrum amplitude of each channel from the mean, while the logarithmic coefficient of variation reflects the nonlinear characteristics of amplitude fluctuation between channels. This allows for a more accurate assessment of the impact of circumferential geometric non-uniformity of the pipeline on guided wave propagation.

[0013] Furthermore, the modal coupling matrix satisfies:

[0014] In the formula, Frequency within the current analysis period Pipeline modes in the modal coupling matrix at the location With pipe mode The coupling coefficient of the constituent elements, This is a normalized constant based on the pipe material properties. Frequency within the current analysis period Circumferential amplitude distortion at the location, and Frequency within the current analysis period Pipeline modes in the modal coupling matrix at the location With pipe mode The theoretical wavenumber in an ideal pipe This is a sensitivity adjustment factor used to match the dimensions of wavenumber difference. Hyperparameters used to prevent the denominator from being zero. It is a natural exponential function. It is the absolute value symbol.

[0015] This invention achieves a scientific evaluation of the modal coupling coefficient by constructing a product model that includes the circumferential amplitude distortion degree and the wavenumber difference exponent. It ensures that the coupling coefficient is positively correlated with the degree of geometric non-uniformity, and that the coupling between modes with similar wavenumbers is stronger. The exponential decay term accurately reflects the influence of the wavenumber difference on the coupling strength, thereby enabling a more accurate evaluation of the energy exchange relationship between modes in actual pipelines.

[0016] Furthermore, the range of values ​​for the normalization constant is: .

[0017] Furthermore, it also includes: performing on-site calibration of the sensitivity adjustment factor, wherein the on-site calibration includes adjusting the value of the sensitivity adjustment factor until the false alarm signal intensity in the weld area is minimized.

[0018] Furthermore, the modal projection matrix satisfies:

[0019] In the formula, Frequency within the current analysis period Modal projection matrix at the location, Frequency within the current analysis period Modal coupling matrix at the location, It is an identity matrix with the same dimensions as the coupling matrix. The stability factor is used to ensure the numerical stability of the inverse matrix. Frequency within the current analysis period The standard orthogonal mode matrix at that location.

[0020] This invention achieves scientific evaluation of modal projection matrices by constructing an inverse matrix product containing an identity matrix and a coupling matrix. It effectively corrects the orthogonal modal matrix under the ideal model, and the stability factor ensures the numerical stability of the inverse matrix. It can accurately suppress intermodal energy leakage and improve the accuracy of modal decomposition and the reliability of defect signal extraction.

[0021] Furthermore, the separation of the structural echo component and the defect signal component includes: extracting the modal component with a circumferential order of zero from the corrected modal coefficient vector as the structural echo component; and extracting the modal component with a circumferential order greater than or equal to 1 from the corrected modal coefficient vector as the defect signal component.

[0022] Furthermore, the processing of the pipeline guided wave signal includes: performing an inverse Fourier transform on the defect signal component to reconstruct the time-domain defect waveform; determining the location of the pipeline defect based on the amplitude and arrival time of the time-domain defect waveform; and completing the pipeline guided wave signal processing.

[0023] This invention achieves accurate reconstruction of the time-domain defect waveform by performing inverse Fourier transform on the defect signal components, preserving the complete time-domain characteristics of the defect signal. The defect location method based on amplitude and arrival time more accurately determines the spatial location of pipeline defects, improving the accuracy and practicality of pipeline health monitoring.

[0024] Secondly, the present invention provides a pipeline guided wave signal processing system, which adopts the following technical solution:

[0025] A pipeline waveguide signal processing system includes a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the aforementioned pipeline waveguide signal processing method is implemented.

[0026] By adopting the above technical solution, a computer program is generated from the above-mentioned pipeline waveguide signal processing method and stored in a memory so that it can be loaded and executed by a processor. In this way, a terminal device can be made based on the memory and the processor for convenient use.

[0027] The present invention has the following technical effects:

[0028] (1) In response to the problem that traditional NME technology is damaged by the geometric non-uniformity of the actual pipeline, such as ellipticity deviation, uneven wall thickness, and eccentricity of the anti-corrosion layer, which leads to energy leakage and false coupling between modes, the present invention uses the multi-channel frequency domain response matrix obtained by the sensor array to calculate the circumferential amplitude distortion degree characterizing the circumferential non-uniformity of the pipeline, and accurately assesses the degree of influence of geometric non-uniformity on guided wave propagation; then, combined with the theoretical wave number of each mode under ideal pipeline, a modal coupling matrix is ​​constructed to assess the energy exchange relationship between different modes. The modal coupling matrix is ​​used to correct the standard orthogonal modal matrix and generate a modal projection matrix containing decoupling logic. This breaks the ideal pipeline assumption of traditional NME technology, compensates for the modal orthogonality deviation caused by geometric non-uniformity from a mathematical perspective, avoids the axisymmetric mode energy being incorrectly projected into the non-axisymmetric mode component, effectively eliminates energy leakage and false coupling, and lays a precise theoretical foundation for structural noise suppression and defect signal extraction.

[0029] (2) Breaking through the limitations of traditional NME technology, which cannot completely eliminate weld coherent noise and is prone to generating false defect artifacts, this invention uses the modified modal projection matrix to perform modal decomposition on the frequency domain response matrix. The generated modified modal coefficient vector can clearly distinguish the axisymmetric modal components reflected by the weld from the non-axisymmetric modal components excited by the defect, thus achieving accurate separation of structural echo and defect signal. This avoids weld noise being misjudged as defect signal and prevents real defect signal from being masked by structural noise. It effectively solves the problem of false alarms and missed alarms caused by signal confusion in traditional methods, improves the detection accuracy of pipeline corrosion, cracks and other defects, and meets the stringent requirements of health monitoring of long-distance pipelines in the energy and chemical industry.

[0030] (3) This invention does not rely on the ideal assumption of regular pipe cross-section and uniform material. Through the dynamic calculation of circumferential amplitude distortion and modal coupling matrix, it can autonomously adapt to different degrees of pipe geometric non-uniformity. Whether it is local geometric deviation in the weld area or uneven wall thickness of the whole pipe, it can achieve stable signal processing effect through real-time correction of modal projection matrix. Compared with the defect of traditional NME technology in actual industrial pipelines, this invention has stronger anti-interference ability. It can be directly applied to complex pipeline inspection scenarios in the energy and chemical industry without the need for preprocessing or additional geometric correction of the pipeline, thus improving the practicality and environmental adaptability of the technology. Attached Figure Description

[0031] Figure 1 This is a flowchart of a pipeline guided wave signal processing method according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the characteristic curve of circumferential amplitude distortion as a function of frequency in a pipeline guided wave signal processing method according to an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the time-domain waveform of the structural echo component separated in a pipeline guided wave signal processing method according to an embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of the time-domain waveform and envelope of the defect signal component separated in a pipeline guided wave signal processing method according to an embodiment of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention discloses a method for processing guided wave signals in a pipeline, referring to... Figure 1 This includes steps S001-S005:

[0037] S001: Acquire multi-channel ultrasonic guided wave signals through a sensor array arranged around the circumference of the pipeline, and convert the multi-channel ultrasonic guided wave signals into a frequency domain response matrix.

[0038] Specifically, before signal processing, it is necessary to obtain raw data reflecting the acoustic characteristics of the pipeline. This step uses a sensor array arranged around the circumference of the pipeline to excite and receive ultrasonic guided wave signals. Each sensor corresponds to one channel. The time-domain signal received by each channel is truncated and subjected to Fast Fourier Transform (FFT) to calculate its power spectral density, thereby constructing the frequency domain response matrix at each frequency in the current analysis period. The elements in the frequency domain response matrix represent the complex response of each channel at a specific frequency.

[0039] S002: Based on the distribution characteristics of the power spectrum amplitude of each channel in the frequency domain response matrix, calculate the circumferential amplitude distortion degree, which characterizes the degree of circumferential non-uniformity of the pipeline.

[0040] It should be noted that the geometric non-uniformity of actual industrial pipelines, such as ellipticity deviation, uneven wall thickness, and eccentricity of the anti-corrosion layer, can lead to an imbalance in the energy distribution of ultrasonic guided waves during circumferential propagation. This energy distribution imbalance is directly reflected in the power spectral amplitude of the received signal in each channel. In uniform pipelines, the power spectral amplitude distribution of each channel is concentrated, while in non-uniform pipelines, the power spectral amplitude of each channel will show significant dispersion. Therefore, this step, by quantifying the distribution differences of the power spectral amplitude of each channel, can indirectly achieve an accurate assessment of the degree of circumferential geometric non-uniformity of the pipeline, providing a core physical basis for subsequent correction of modal orthogonality deviations.

[0041] Specifically, the circumferential amplitude distortion satisfies:

[0042] ;

[0043] In the formula, Frequency within the current analysis period Circumferential amplitude distortion at the location, The total number of channels. For the current analysis period, the [number]th Each channel at frequency The power spectral amplitude at a given point is obtained by calculating the power spectral density after performing an FFT on the received time-domain signal. For all channels in the current analysis period at frequency The mean of the power spectrum amplitude at that location, For all channels in the current analysis period at frequency The standard deviation of the power spectrum amplitude at that location, It is the natural logarithm function. It is the absolute value symbol.

[0044] Among them, the coefficient of variation is used As a parameter of the logarithmic function, it ensures the rationality of the calculation, because As a dimensionless value, the circumferential amplitude distortion becomes a purely numerical index independent of the measurement unit, thus objectively reflecting the degree of geometric non-uniformity of the pipeline, unaffected by external factors such as sensor type and gain settings. The circumferential amplitude distortion characterizes the asymmetry of guided wave energy distribution along the circumference of the pipeline. When the pipeline exhibits ellipticity or eccentricity, the value of the circumferential amplitude distortion increases monotonically, quantitatively mapping the degree of geometric perturbation of the physical pipeline relative to an ideal cylindrical waveguide.

[0045] like Figure 2As shown, the horizontal axis represents the analysis frequency, covering the commonly used operating frequency bands for ultrasonic guided wave testing of pipelines; the vertical axis represents the circumferential amplitude distortion degree, and the larger the value, the more significant the circumferential geometric non-uniformity of the pipeline, such as ellipticity deviation, wall thickness inhomogeneity, etc. It can be observed from the curve that the non-uniform response of the pipeline is different at different frequencies, which provides data support for subsequent targeted construction of modal coupling matrix and optimization of modal decomposition accuracy.

[0046] S003: Based on the circumferential amplitude distortion and the theoretical wavenumber of each pipe mode under ideal pipe conditions, construct a mode coupling matrix to evaluate the energy exchange relationship between modes.

[0047] It should be noted that in an ideal pipeline, different modes are strictly orthogonal with no energy exchange. However, the geometric non-uniformity of a real pipeline disrupts this orthogonality, leading to energy leakage between modes, i.e., modal coupling. The coupling strength is positively correlated with the degree of non-uniformity and closely related to the wavenumber characteristics of the modes themselves; modes with similar wavenumbers are more prone to strong coupling. Therefore, this step, by fusing circumferential amplitude distortion and theoretical wavenumber, can accurately model the energy exchange intensity between different modes, providing a numerical characterization basis for subsequent correction of the mode matrix.

[0048] Specifically, the modal coupling matrix satisfies:

[0049] ;

[0050] In the formula, Frequency within the current analysis period Pipeline modes in the modal coupling matrix at the location With pipe mode The coupling coefficient of the constituent elements, This is a normalization constant based on the pipe material properties, and the range of values ​​for the normalization constant is... For steel pipes, usually... ; Frequency within the current analysis period Circumferential amplitude distortion at the location, and Frequency within the current analysis period Pipeline modes in the modal coupling matrix at the location With pipe mode The theoretical wavenumber under ideal pipe conditions can be found in a standard database of dispersion curves, such as using Disperse software or a pipe guided wave dispersion curve manual. The sensitivity adjustment factor used to match the wavenumber difference dimension can be determined through field data calibration, such as by adjusting... To minimize false alarm signals in the weld area, the initial value is 1; For example, a hyperparameter used to prevent the denominator from being zero, The dimensions are consistent with the sensitivity adjustment factor; It is a natural exponential function. It is the absolute value symbol.

[0051] The exponential term indicates that the closer the theoretical wavenumbers of the two pipe modes are, the higher the exponential value becomes. The smaller the value and the larger the circumferential amplitude distortion, the more significant the coupling effect between the two pipe modes. This means that the circumferential amplitude distortion causes the originally orthogonal pipe modes to produce non-zero overlapping components during mathematical projection. At this time, the coupling coefficient provides a key correction basis for subsequent mode decomposition, and can effectively offset the modal leakage effect by correcting the projection operator, thereby improving the accuracy and reliability of defect detection.

[0052] S004: The orthogonal mode matrix obtained based on the pipe waveguide theory is corrected using the mode coupling matrix to generate a mode projection matrix containing decoupling logic.

[0053] It should be noted that the standard orthogonal mode matrix is ​​derived based on the ideal pipe waveguide assumption and does not consider the modal coupling phenomenon in actual pipes. Directly using it for signal decomposition will lead to energy leakage and signal misinterpretation. Therefore, this step incorporates the modal coupling matrix into the correction process, integrating the coupling information of the actual operating conditions into the ideal mode matrix. Decoupling logic is achieved through inverse matrix operations, enabling the corrected mode projection matrix to adapt to the actual propagation characteristics of non-uniform pipes and ensuring the accuracy of subsequent mode decomposition.

[0054] Specifically, the modal projection matrix satisfies:

[0055] ;

[0056] In the formula, Frequency within the current analysis period Modal projection matrix at the location, Frequency within the current analysis period Modal coupling matrix at the location, It is an identity matrix with the same dimensions as the coupling matrix. As an example, a stability factor is used to guarantee the numerical stability of the inverse matrix. ; Frequency within the current analysis period The standard orthogonal mode matrix at the location is calculated based on the ideal pipe waveguide theory and obtained through the pipe guided wave dispersion curve.

[0057] in, Essentially, it is a deconvolution or decoupling process. When using this operator to process signals, it can automatically cancel out modal leakage caused by pipeline geometric deformation, ensuring that the decomposed modal coefficients return to their true physical properties.

[0058] S005: Modal decomposition of the frequency domain response matrix is ​​performed using the modal projection matrix to obtain the corrected modal coefficient vector. The structural echo component used to identify weld structures in the pipeline and the defect signal component used to identify defects in the pipeline are then separated from the corrected modal coefficient vector to realize the processing of pipeline guided wave signals.

[0059] It should be noted that the corrected modal projection matrix has eliminated modal coupling interference caused by geometric non-uniformity, and can accurately decompose the frequency domain response matrix into coefficient vectors of each independent mode. Therefore, based on the difference in modal order, this step can effectively separate structural echoes from defect signals, avoid misjudging weld noise as defects, and ensure that defect signals are not masked by structural noise.

[0060] Specifically, the corrected modal coefficient vector satisfies:

[0061] ;

[0062] In the formula, Frequency within the current analysis period The corrected modal coefficient vector at that point, Frequency within the current analysis period The transpose of the modal projection matrix at that point. This is the frequency domain response matrix.

[0063] Specifically, separating the structural echo component and the defect signal component includes:

[0064] In the corrected modal coefficient vector, modal components with zero circumferential order are extracted as structural echo components, such as longitudinal waves. ;

[0065] In the corrected modal coefficient vector, modal components with a circumferential order greater than or equal to 1 are extracted as defect signal components, such as bending waves. .

[0066] like Figure 3 As shown, the horizontal axis represents time, covering the main propagation period of the structural echo; the vertical axis represents the signal amplitude, reflecting the energy intensity of the structural echo. This waveform is obtained by extracting the circumferentially ordered zero modal components from the corrected modal coefficient vector, containing only the reflection signal from the isoaxially symmetric weld structure. It effectively filters out defect signals and spurious interference caused by modal coupling. Figure 3The waveform of the structural echo is regular and the peak is clear, with no obvious noise. This verifies the effectiveness of the mode decomposition and component separation method of the present invention in suppressing non-structural interference and purifying structural echo signals, providing a clean signal basis for subsequent elimination of weld noise interference to defect detection.

[0067] Specifically, the processing of the guided wave signal in the pipeline includes:

[0068] The defect signal component is subjected to inverse Fourier transform to reconstruct the time-domain defect waveform. Based on the amplitude and arrival time of the time-domain defect waveform, the location of the pipeline defect is determined, and pipeline guided wave signal processing is completed.

[0069] like Figure 4 As shown, the horizontal axis represents time, and the vertical axis represents the signal amplitude, reflecting the energy intensity of the defect signal. The estimated defect location of 0.899m is also marked. This waveform is reconstructed by performing an inverse Fourier transform on the extracted circumferential mode components with an order of not less than 1. It has been separated from the structural echo components and is free from weld noise interference. Figure 4 The solid line represents the time-domain waveform of the defect, and the dashed line represents the waveform envelope. The peak position and arrival time of the defect signal can be clearly identified. Combined with the propagation speed of ultrasonic guided waves in the pipeline, the estimated position of the defect is 0.899m calculated by the arrival time. This verifies that the method of the present invention can accurately separate and reconstruct the defect signal, and accurately locate the defect based on the time-domain characteristics, providing a reliable basis for the quantitative detection of pipeline defects.

[0070] This invention also discloses a pipeline waveguide signal processing system, including a processor and a memory. The memory stores computer program instructions, which, when executed by the processor, implement a pipeline waveguide signal processing method according to the present invention.

[0071] The system also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

[0072] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for processing guided wave signals in a pipeline, characterized in that, include: Multi-channel ultrasonic guided wave signals are acquired by a sensor array arranged around the circumference of the pipe, and the multi-channel ultrasonic guided wave signals are converted into a frequency domain response matrix. Based on the distribution characteristics of the power spectrum amplitude of each channel in the frequency domain response matrix, the circumferential amplitude distortion degree, which characterizes the degree of circumferential non-uniformity of the pipeline, is calculated. ; In the formula, Frequency within the current analysis period Circumferential amplitude distortion at the location, The total number of channels. For the current analysis period, the [number]th Each channel at frequency The power spectral amplitude at that point For all channels in the current analysis period at frequency The mean of the power spectrum amplitude at that location, For all channels in the current analysis period at frequency The standard deviation of the power spectrum amplitude at that point It is the natural logarithm function. It is the absolute value symbol; Based on the circumferential amplitude distortion and the theoretical wavenumbers of each pipe mode under ideal pipe conditions, a modal coupling matrix is ​​constructed to evaluate the energy exchange relationship between modes. ; In the formula, Frequency within the current analysis period Pipeline modes in the modal coupling matrix at the location With pipe mode The coupling coefficient of the constituent elements, This is a normalized constant based on the pipe material properties. and Frequency within the current analysis period Pipeline modes in the modal coupling matrix at the location With pipe mode The theoretical wavenumber in an ideal pipe This is a sensitivity adjustment factor used to match the dimensions of wavenumber difference. Hyperparameters used to prevent the denominator from being zero. It is a natural exponential function; The orthogonal mode matrix obtained based on the pipe waveguide theory is corrected using the mode coupling matrix to generate a mode projection matrix containing decoupling logic; Modal decomposition of the frequency domain response matrix is ​​performed using the modal projection matrix to obtain the corrected modal coefficient vector. The structural echo component used to identify weld structures in the pipeline and the defect signal component used to identify defects in the pipeline are then separated from the corrected modal coefficient vector, thus realizing the processing of pipeline guided wave signals.

2. The pipeline guided wave signal processing method according to claim 1, characterized in that, The process of converting multi-channel ultrasonic guided wave signals into a frequency domain response matrix includes: The time-domain signal of each channel is truncated and subjected to Fast Fourier Transform to calculate the power spectral density, thereby constructing the frequency domain response matrix at each frequency within the current analysis period.

3. The pipeline guided wave signal processing method according to claim 1, characterized in that, The normalization constant takes values ​​in the range of: .

4. The pipeline guided wave signal processing method according to claim 1, characterized in that, Also includes: The sensitivity adjustment factor is calibrated on-site, and the on-site calibration includes adjusting the value of the sensitivity adjustment factor until the false alarm signal intensity in the weld area is minimized.

5. The pipeline guided wave signal processing method according to claim 1, characterized in that, The modal projection matrix satisfies: ； In the formula, Frequency within the current analysis period Modal projection matrix at the location, Frequency within the current analysis period Modal coupling matrix at the location, It is an identity matrix with the same dimensions as the coupling matrix. The stability factor is used to ensure the numerical stability of the inverse matrix. Frequency within the current analysis period The standard orthogonal mode matrix at that location.

6. The pipeline guided wave signal processing method according to claim 1, characterized in that, The separation of the structural echo component for identifying weld structures in the pipeline and the defect signal component for identifying defects in the pipeline includes: In the corrected modal coefficient vector, the modal components with circumferential order of zero are extracted as structural echo components; In the corrected modal coefficient vector, modal components with a circumferential order greater than or equal to 1 are extracted as defect signal components.

7. The pipeline guided wave signal processing method according to claim 1, characterized in that, The processing of the guided wave signal for the pipeline includes: The defect signal component is subjected to inverse Fourier transform to reconstruct the time-domain defect waveform. Based on the amplitude and arrival time of the time-domain defect waveform, the location of the pipeline defect is determined, and pipeline guided wave signal processing is completed.

8. A pipeline guided wave signal processing system, characterized in that, include: A processor and a memory, the memory storing computer program instructions that, when executed by the processor, implement a pipe waveguide signal processing method according to any one of claims 1-7.

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