Defect three-dimensional reconstruction method and device based on magnetic flux leakage and magnetic disturbance signals

Abstract

The invention discloses a defect three-dimensional reconstruction method and device based on magnetic flux leakage and a magnetic disturbance signal, and the method comprises the steps: firstly, achieving the accurate reconstruction of a defect opening contour through the sensitivity of the magnetic disturbance signal to the defect opening contour, and improving the accuracy of a forward model used for inversion; secondly, based on the sensitivity of a magnetic flux leakage signal to the defect depth, the magnetic flux leakage signal is used as a depth reconstruction standard, the reconstruction precision of a defect depth contour is achieved, and finally three-dimensional representation of the defect is achieved by combining the reconstructed opening contour and the depth contour. Compared with an existing inversion method, the method has the advantages of being high in reconstruction precision, easy to operate and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of pipelines, and in particular to a three-dimensional reconstruction method and device for defects based on magnetic flux leakage and magnetic perturbation signals. Background Art

[0002] In ensuring the safe operation of oil pipelines, the internal magnetic flux leakage detection technology of pipelines has become an effective means to detect the existence of defects in advance. Therefore, accurately characterizing the three-dimensional morphology of defects can provide data support for the safe operation of pipelines.

[0003] According to the analysis of conventional magnetic flux leakage defect reconstruction methods, the three-dimensional reconstruction accuracy of defects mainly depends on the accuracy of the forward model and the optimization ability of the optimization algorithm. In the traditional magnetic flux leakage detection process, due to the complex magnetic field diffusion phenomenon at the defect edge, the reconstruction of the opening contour is inaccurate, which in turn affects the reconstruction accuracy of the defect depth contour. By comparing the reconstruction accuracy of the defect opening contour between the magnetic perturbation signal and the magnetic flux leakage signal, it can be seen that the magnetic perturbation technology can accurately reconstruct the defect opening contour, but it is not sensitive to the depth change and cannot accurately reconstruct the defect depth using the magnetic perturbation signal.

[0004] Therefore, how to improve the three-dimensional reconstruction accuracy of complex defects has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a three-dimensional reconstruction method and device for defects based on magnetic flux leakage and magnetic perturbation signals to solve the above technical problems.

[0006] To achieve the above purpose, the present invention provides a three-dimensional reconstruction method for defects based on magnetic flux leakage and magnetic perturbation signals, the method comprising:

[0007] Reconstructing the defect opening contour based on the magnetic perturbation signal;

[0008] Establishing a forward model according to the defect opening contour;

[0009] Performing defect depth contour inversion and iteration on the forward model, and comparing the magnetic flux leakage measurement signal and the magnetic flux leakage prediction signal of the forward model to obtain the predicted defect depth contour;

[0010] Obtaining the three-dimensional contour of the defect inversion according to the defect opening contour and the predicted defect depth contour.

[0011] The present invention also provides a three-dimensional reconstruction device for defects based on magnetic flux leakage and magnetic perturbation signals, the device comprising:

[0012] A reconstruction unit for reconstructing the defect opening contour based on the magnetic perturbation signal;

[0013] A building unit, configured to build a forward model according to a defect opening profile;

[0014] An inversion unit, configured to perform defect depth profile inversion and iteration on the forward model, and compare the magnetic flux leakage measurement signal of the forward model with the magnetic flux leakage prediction signal to obtain a defect prediction depth profile;

[0015] An obtaining unit, configured to obtain a three-dimensional profile of the defect inversion according to the defect opening profile and the defect prediction depth profile.

[0016] The present invention further provides an electronic device, including: a processor, the processor being coupled to a memory;

[0017] The processor is configured to read and execute a computer program stored in the memory to implement the method described in any one of the above.

[0018] The present invention further provides a computer-readable storage medium, in which a program or an instruction is stored, and when the program or the instruction is executed by a processor, the method described in any one of the above is implemented.

[0019] The technical effects and advantages of the present invention:

[0020] Based on the respective advantages of magnetic flux leakage and magnetic perturbation signals in defect reconstruction, the present invention realizes accurate three-dimensional reconstruction of defects. First, by utilizing the sensitivity of the magnetic perturbation signal to the defect opening profile, accurate reconstruction of the defect opening profile is achieved, improving the accuracy of the forward model used in inversion. Secondly, based on the sensitivity of the magnetic flux leakage signal to the defect depth, the magnetic flux leakage signal is used as a standard for depth reconstruction, realizing the reconstruction accuracy of the defect depth profile. Finally, the three-dimensional characterization of the defect is achieved by combining the reconstructed opening profile and depth profile. Compared with the existing inversion methods, the present invention has the advantages of high reconstruction accuracy and simple operation.

[0021] Other features and advantages of the present invention will be described in the subsequent description, and some of them will be obvious from the description, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the structures pointed out in the description and the drawings. Description of the Drawings

[0022] Figure 1 It is a flowchart of a three-dimensional defect reconstruction method based on magnetic flux leakage and magnetic perturbation signals;

[0023] Figure 2 It is a comparison diagram of the reconstructed defect opening profile and the actual opening profile;

[0024] Figure 3 It is a comparison diagram of the measurement signal and the inversion signal after multiple iterations;

[0025] Figure 4It is a comparison diagram of the defect inversion depth profile and the actual depth profile;

[0026] Figure 5 It is a diagram of an electronic device. Specific implementation manner

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope that can be covered by the technical content disclosed in the present invention without affecting the effects that the present invention can produce and the purposes that can be achieved. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of clear narration, and are not used to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationship should also be regarded as the scope under which the present invention can be implemented without substantial change in technical content.

[0029] To solve the deficiencies of the prior art, the present invention discloses a three-dimensional defect reconstruction method based on magnetic flux leakage and magnetic perturbation signals. The following is a detailed explanation of this method in combination with Figure 1 to explain this method in detail.

[0030] (1) Perform magnetic flux leakage and magnetic perturbation planar scanning detection in the defect area.

[0031] Specifically: Fix the magnetic flux leakage sensor and the magnetic perturbation sensor on the scanning probe and scan the defect. Use Hall sensors in the magnetic flux leakage sensor and the magnetic perturbation sensor to measure the By and Bz components of the magnetic induction intensity near the defect respectively.

[0032] (2) Reconstruct the defect opening profile based on the magnetic perturbation signal.

[0033] Specifically: After obtaining the magnetic perturbation signal near the defect, perform denoising and normalization processing on the magnetic perturbation signal; then use the Contour algorithm and an appropriate threshold to perform image recognition on the processed magnetic perturbation signal, extract the edge of the defect area, and reconstruct the defect opening profile.

[0034] (3) Establish a forward model.

[0035] Specifically, based on the defect opening profile reconstructed from the magnetic perturbation signal, a forward finite element model for defect depth optimization is established in the finite element software, which transforms the defect depth inversion into an optimization problem of the defect depth profile.

[0036] (4) Adopt a suitable optimization algorithm to perform defect depth profile inversion.

[0037] Specifically, the particle swarm optimization algorithm is used to implement the iterative process of defect depth profile inversion. And the minimum error between the magnetic flux leakage measurement signal of the forward model and the magnetic flux leakage prediction signal obtained in step 1 during the iterative process is used as the objective function. The objective function is expressed as:

[0038]

[0039] In the formula, M is the number of sampling points of the magnetic flux leakage signal; A(A1, A2,..., A M ) is the magnetic flux leakage measurement signal of the forward model; B(B1, B2,..., B M ) is the magnetic flux leakage prediction signal. When the relative change between the objective function values of two adjacent iterations is less than the set threshold, the termination condition is satisfied. The defect depth parameter obtained by the optimization algorithm is the predicted defect depth, and the predicted defect depth profile is obtained.

[0040] (5) Combining the defect opening profile in step (2) and the predicted defect depth profile in step (4), the three-dimensional profile of the defect inversion can be obtained.

[0041] To better explain the present invention, embodiments are also provided below.

[0042] Embodiment

[0043] This embodiment is for the reconstruction of the three-dimensional morphology of an 8-shaped defect, and the reconstruction method is as follows:

[0044] (1) Conduct magnetic flux leakage and magnetic perturbation plane scanning detections in the defect area. Specifically, a magnetic flux leakage sensor and a magnetic perturbation sensor are used to measure the magnetic field information near the defect respectively.

[0045] (2) Reconstruct the opening profile using the magnetic perturbation imaging result. Specifically, the magnetic perturbation signal is denoised and normalized, and the processed magnetic perturbation signal is subjected to image recognition using the Contour algorithm and a suitable threshold to extract the edge of the defect area to obtain the defect opening profile. Figure 2 It is a comparison diagram of the actual opening profile and the reconstructed profile of the defect.

[0046] (3) Establish a forward model. Specifically, based on the defect opening profile reconstructed from the magnetic perturbation signal, a forward finite element model for defect depth optimization is established in the finite element software.

[0047] (4) Use a suitable optimization algorithm for defect depth profile inversion. Specifically: The particle swarm optimization algorithm is used to implement the iterative process of defect depth profile inversion. Figure 3 It is a comparison graph of the measured signal and the inverted signal after multiple iterations, Figure 4 It is a comparison graph of the actual depth profile of the defect and the inverted depth profile.

[0048] (5) Combine the defect opening profile obtained in step 2 and the defect predicted depth profile obtained in step 4 to obtain the defect three-dimensional profile.

[0049] It can be seen from the inversion results that in terms of opening profile reconstruction, the length and width estimation errors of the figure-eight defect based on the magnetic perturbation detection method are approximately 1.1% and 4.8% respectively. In terms of depth profile reconstruction, the depth error at the maximum position of the defect is 2.8%. The inversion results show that the defect three-dimensional reconstruction combined method based on magnetic flux leakage and magnetic perturbation signals can reconstruct the defect three-dimensional profile with high precision.

[0050] The present invention also provides a defect three-dimensional reconstruction device based on magnetic flux leakage and magnetic perturbation signals. The device includes:

[0051] A reconstruction unit for reconstructing the defect opening profile based on the magnetic perturbation signal;

[0052] A building unit for building a forward model according to the defect opening profile;

[0053] An inversion unit for performing defect depth profile inversion and iteration on the forward model, and comparing the magnetic flux leakage measurement signal of the forward model with the magnetic flux leakage prediction signal to obtain the defect predicted depth profile;

[0054] An obtaining unit for obtaining the inverted three-dimensional profile of the defect according to the defect opening profile and the defect predicted depth profile.

[0055] Since the content protected by this device is similar to the content protected by the above method, no more introduction will be made here. For details, please refer to the discussion part of the above method.

[0056] The present invention also provides a device, such as Figure 5As shown. The electronic device includes: at least one processor, at least one communication interface, at least one memory, and at least one communication bus; optionally, the communication interface may be the interface of a communication module, such as the interface of a GSM module; the processor may be a processor CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention. The memory may include high-speed RAM memory and may also include non-volatile memory, such as at least one disk memory. Among them, the memory stores a program, and the processor calls the program stored in the memory to execute the method provided in the above embodiments of the present application.

[0057] Corresponding to the above method of the present application, the present application also provides a computer storage medium. The computer storage medium stores a computer program, and the computer program is run by a processor to execute the method provided in the above embodiments of the present application.

[0058] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A three-dimensional reconstruction method for defects based on magnetic flux leakage and magnetic perturbation signals, characterized in that, The method includes: Reconstructing the defect opening profile based on the magnetic perturbation signal; Establishing a forward model according to the defect opening profile; Performing defect depth profile inversion and iteration on the forward model, and comparing the magnetic flux leakage measurement signal of the forward model with the magnetic flux leakage prediction signal to obtain the predicted defect depth profile; Obtaining the three-dimensional profile of the defect inversion according to the defect opening profile and the predicted defect depth profile.

2. The method according to claim 1, characterized in that, Before reconstructing the defect opening profile based on the magnetic perturbation signal, it further includes: Fixing a magnetic flux leakage sensor and a magnetic perturbation sensor on a scanning probe and scanning the defect to obtain a magnetic flux leakage prediction signal and a magnetic perturbation signal.

3. The method according to claim 1, characterized in that, Reconstructing the defect opening profile based on the magnetic perturbation signal includes: Denosing and normalizing the magnetic perturbation signal to obtain a processed magnetic perturbation signal; Performing image recognition on the processed magnetic perturbation signal using the Contour algorithm and extracting the edge of the defect; Obtaining the defect opening profile according to the edge of the defect.

4. The method according to claim 1, characterized in that, Establishing a forward model according to the defect opening profile includes: Establishing a forward finite element model with optimized defect depth in finite element software according to the defect opening profile.

5. The method according to claim 1, characterized in that, Performing defect depth profile inversion and iteration on the forward model, and comparing the magnetic flux leakage measurement signal of the forward model with the magnetic flux leakage prediction signal to obtain the predicted defect depth profile, includes: Using a particle swarm optimization algorithm to perform defect depth profile inversion and iteration on the forward model to obtain the magnetic flux leakage measurement signal of the forward model; Taking the minimum error between the magnetic flux leakage measurement signal of the forward model and the magnetic flux leakage prediction signal as the objective function; Obtaining the predicted defect depth profile according to the objective function.

6. The method according to claim 5, characterized in that, Obtaining the predicted defect depth profile according to the objective function includes: Judging whether the relative change between two adjacent objective function values is less than a predetermined threshold. If so, obtaining the predicted defect depth profile.

7. The method according to claim 6, characterized in that, The formula of the objective function is as follows: Among them, M is the number of sampling points of the magnetic flux leakage signal; A(A1, A2, …, A M ) is the magnetic flux leakage measurement signal of the forward model; B(B1, B2, …, B M ) is the magnetic flux leakage prediction signal.

8. A three-dimensional reconstruction device for defects based on magnetic flux leakage and magnetic perturbation signals, characterized in that, The device includes: A reconstruction unit for reconstructing the defect opening profile based on the magnetic perturbation signal; An establishment unit for establishing a forward model according to the defect opening profile; An inversion unit for performing defect depth profile inversion and iteration on the forward model, and comparing the magnetic flux leakage measurement signal of the forward model with the magnetic flux leakage prediction signal to obtain the predicted defect depth profile; An obtaining unit for obtaining the three-dimensional profile of the defect inversion according to the defect opening profile and the predicted defect depth profile.

9. An electronic device, characterized in that, It includes: A processor, and the processor is coupled with a memory; The processor is configured to read and execute a computer program stored in the memory to implement the method according to any one of claims 1-7.

10. A computer-readable storage medium storing a program or instructions, characterized in that, The program or instruction, when executed by the processor, implements the method according to any one of claims 1-7.

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