Backward projection imaging method, system, equipment and medium for defect detection of external insulation equipment of power system

Abstract

The invention belongs to the technical field of external insulation equipment detection, discloses a backward projection imaging method, system and equipment for defect detection of external insulation equipment of a power system and a medium, and aims to solve the problem of low imaging efficiency caused by large repeated calculation amount of an electromagnetic wave propagation path in an existing backward projection imaging algorithm. The method comprises the following steps of: firstly, selecting a reference detection azimuth to calculate electromagnetic wave propagation path distribution by utilizing an axial symmetry structure characteristic of external insulation equipment, then rotating the reference path distribution to other detection azimuths to obtain to-be-interpolated path distribution, and then accurately calculating a target pixel point by adopting an inverse distance weighted interpolation method to obtain a target pixel point. And finally, the above steps are repeated to obtain path data of all detection orientations for imaging. According to the method, repeated calculation of an electromagnetic wave propagation path is remarkably reduced through a parameter multiplexing mode, the back projection imaging efficiency is greatly improved on the premise that the imaging precision is guaranteed, and the requirement for on-site rapid detection of external insulation equipment of a power system can be met.

Description

Technical Field

[0001] This invention belongs to the field of external insulation equipment detection technology, specifically relating to a back projection imaging method, system, equipment, and medium for detecting defects in external insulation equipment of power systems. Background Technology

[0002] Back projection (BP) algorithms originated from the projection slicing theorem in CT imaging and offer high imaging resolution. Their core principle is to obtain the energy intensity of a detection point by reverse-tracking electromagnetic waves based on their propagation time. In the field of defect detection in external insulation equipment of power systems, the BP algorithm is often used in conjunction with synthetic aperture radar (SAR). The radar acquires the dielectric distribution characteristics of the target by transmitting detection signals to and receiving reflected signals from different detection azimuths. The BP algorithm performs back projection imaging on the received signals from each detection azimuth and coherently processes the images from each azimuth, ultimately achieving radar imaging of the external insulation equipment.

[0003] However, the BP algorithm faces the problem of high computational cost in practical engineering applications, which seriously hinders its widespread adoption. Among the most time-consuming steps is calculating the electromagnetic wave propagation path for each detection azimuth. This process requires calculating the electromagnetic wave propagation path between the radar antenna and each detection point in the imaging space when the antenna is in different positions. Given a fixed number of pixels in the imaging space, the number of detection azimuths in synthetic aperture radar linearly affects the imaging time. High-precision BP imaging typically requires a large number of detection azimuths, further exacerbating the computational burden and posing a challenge to fast BP imaging.

[0004] On the other hand, the external insulation equipment of power systems is typically axisymmetric, with essentially the same structure in all directions. This structural characteristic means that, with parameters such as antenna distance and the synthetic aperture radar trajectory relative to the object's downward angle remaining constant, electromagnetic waves emitted by radars from different detection azimuths will reach the same structural parts of the external insulation equipment, and the subsequent reflections and refractions within its internal media layers will also be essentially the same. Therefore, under these conditions, independently solving for the electromagnetic wave propagation paths from each detection azimuth constitutes computational redundancy and reduces overall computational efficiency.

[0005] In summary, the existing technology lacks a backward projection imaging method that can utilize the axisymmetric structural characteristics of external insulation equipment to reduce the repetitive calculation of electromagnetic wave propagation paths, resulting in imaging efficiency that is difficult to meet the needs of engineering applications. Summary of the Invention

[0006] Based on the aforementioned shortcomings and deficiencies in the prior art, one of the objectives of this invention is to at least solve one or more of the aforementioned problems in the prior art. In other words, one of the objectives of this invention is to provide a backward projection imaging method, system, device, and medium for detecting defects in external insulation equipment of power systems that meets one or more of the aforementioned requirements, so as to reduce the redundant calculation of electromagnetic wave propagation paths and improve the efficiency of backward projection imaging.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a backward projection imaging method for detecting defects in external insulation equipment of a power system, comprising the steps of: S1. Select any detection azimuth as the reference detection azimuth, and use the electromagnetic wave propagation path calculation method to obtain the electromagnetic wave propagation path data of each pixel in the imaging area under the reference detection azimuth, and form a reference path distribution. S2. Utilizing the axisymmetric structural characteristics of the external insulation equipment of the power system, the reference path distribution is rotated by a preset angle along the axis of symmetry of the equipment under test to obtain the interpolation path distribution corresponding to the target detection orientation; S3. For each target pixel in the target detection orientation, determine its multiple neighboring reference pixels in the path distribution to be interpolated. S4. Based on the distance between the target pixel and the plurality of reference pixels, the electromagnetic wave propagation path data of the target pixel is calculated using the inverse distance weighted interpolation method. S5. Repeat steps S2 to S4 until electromagnetic wave propagation path data of each pixel under all detection orientations are obtained for back projection imaging.

[0008] As a preferred option: The electromagnetic wave propagation path data in step S1 includes the electromagnetic wave propagation distance or propagation time.

[0009] As a preferred option: In step S2, the preset angle is the angle difference between the reference detection azimuth and the target detection azimuth.

[0010] As a preferred option: In step S2, the imaging area of ​​the reference path distribution is smaller than the imaging area of ​​the path distribution to be interpolated.

[0011] As a preferred embodiment, in step S3, the plurality of neighboring reference pixels specifically refer to: In the path distribution to be interpolated, the four grid pixels closest to the target pixel.

[0012] As a preferred embodiment, in step S4, the calculation formula for the inverse distance weighted interpolation method is as follows: , In the formula, This is the electromagnetic wave propagation path data for the target pixel. The distance between the target pixel and its neighboring reference pixels. For the propagation path distance of the reference pixel, The inverse distance weight is used as the reference pixel.

[0013] As a preferred option: In step S4, when the target pixel coincides with a reference pixel in the path distribution to be interpolated, the electromagnetic wave propagation path data of the reference pixel is directly assigned to the target pixel.

[0014] In a second aspect, the present invention provides a rear projection imaging system for detecting defects in external insulation equipment of a power system, for implementing the rear projection imaging method as described in the first aspect.

[0015] Thirdly, the present invention provides an electronic device, the computer device including a memory, a processor and a computer program, wherein when the computer program is executed by the processor, it implements the rear projection imaging method as described in the first aspect.

[0016] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the rear projection imaging method as described in the first aspect.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention employs the concept of parameter reuse, utilizing the axisymmetric structural characteristics of external insulation equipment in power systems to rotate and reuse the electromagnetic wave propagation path calculation results from the reference detection azimuth to other detection azimuths. This avoids the tedious calculation of electromagnetic wave propagation paths for each detection azimuth. Since electromagnetic wave propagation path calculation is the most time-consuming step in the back projection imaging algorithm, this invention significantly improves overall imaging efficiency by reducing redundant calculations.

[0018] 2. Based on parameter reuse, this invention uses an inverse distance-weighted interpolation method to refine the distribution of the path to be interpolated after rotation. For overlapping cases, values ​​are directly assigned, and for non-overlapping cases, the propagation path data of the target pixel is accurately calculated based on distance weighting.

[0019] 3. This invention fully utilizes the axisymmetric structural characteristics of external insulation equipment in power systems, and is applicable to various power equipment with axisymmetric structures, such as insulators, bushings, and post insulators. Furthermore, the method of this invention does not rely on a specific electromagnetic wave propagation path calculation method and can be used in conjunction with various existing path calculation methods, exhibiting good compatibility and universality.

[0020] 4. This invention effectively solves the problem that the large computational load of the back projection imaging algorithm makes it difficult to promote and apply in engineering, providing a feasible technical solution for rapid on-site inspection of external insulation equipment in power systems. By improving imaging efficiency, this invention helps to upgrade and accelerate the quality inspection of power materials, meeting the power industry's dual requirements for the timeliness and accuracy of equipment inspection.

[0021] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic flowchart of the backward projection imaging method described in Embodiment 1 of the present invention.

[0024] Figure 2 This is a schematic diagram of the electromagnetic wave propagation path parameter multiplexing concept described in Embodiment 1 of the present invention.

[0025] Figure 3 This is a schematic diagram of rotating reference orientation data and obtaining calculated orientation data as described in Embodiment 1 of the present invention.

[0026] Figure 4 This is a schematic diagram of the pixel value acquisition method for the overlapping situation described in Embodiment 1 of the present invention.

[0027] Figure 5 This is a schematic diagram illustrating the calculation of the distance from a pixel to its four surrounding pixels as described in Embodiment 1 of the present invention.

[0028] Figure 6 This is a schematic diagram illustrating the calculation of the pixel value of the target pixel using the inverse distance weighting algorithm as described in Embodiment 1 of the present invention.

[0029] Figure 7 This is a structural diagram of the electronic device described in Embodiment 3 of the present invention.

[0030] Figure 8This is a schematic diagram of the target under test with a circular cavity as described in Embodiment 5 of the present invention.

[0031] Figure 9 This is a schematic diagram of different radar detection orientations as described in Embodiment 5 of the present invention.

[0032] Figure 10 This is a schematic diagram of the back projection imaging results for calculating all detection azimuths as described in Embodiment 5 of the present invention.

[0033] Figure 11 This is a schematic diagram of the back projection imaging result using the parameter reuse method described in Embodiment 5 of the present invention.

[0034] Icon labels: 700. Electronic equipment; 701. Processor; 702. Communication bus; 703. User interface; 704. Network interface; 705. Memory. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0036] In the following description, several embodiments of the present invention are provided. Different embodiments can be substituted or combined. Therefore, the present invention can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present invention should also be considered to include embodiments containing one or more other possible combinations of A, B, C, and D, even if such embodiments are not explicitly described in the following text.

[0037] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of the invention. Various processes or components may be appropriately omitted, substituted, or added to the various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0038] To facilitate a better understanding of the embodiments of the present invention, its application scenarios will be explained before providing a detailed explanation of the specific implementation methods.

[0039] The back projection imaging method described in this specification is applied to non-destructive testing scenarios for external insulation equipment in power systems. Specifically, it includes the detection of internal defects in power equipment with axisymmetric structures, such as insulators, bushings, and post insulators, during factory quality inspection, in-service operation inspection, and fault diagnosis and troubleshooting. In these scenarios, the application of the back projection imaging method aims to acquire images of the internal structure of the equipment using radar detection technology. By reducing the redundant calculation of electromagnetic wave propagation paths through parameter reuse, it significantly improves imaging efficiency while ensuring imaging accuracy, enabling rapid and accurate location of internal defects in external insulation equipment and meeting the dual requirements of timeliness and accuracy for on-site inspection in power systems.

[0040] The following is a brief explanation of the power system external insulation equipment, back projection imaging, reference detection azimuth, electromagnetic wave propagation path calculation method, axisymmetric structure, target detection azimuth, and inverse range weighted interpolation involved in several embodiments of this specification: External insulation equipment in power systems refers to equipment used in power systems for insulation and support, mainly including insulators, bushings, and post insulators. This type of equipment is typically composed of multiple layers of dielectric materials arranged radially. For example, an insulator, from the outside in, consists of skirts, a sheath, and a core rod, presenting a multi-layered circular structure in cross-section. Their common characteristic is that their geometry and dielectric distribution are axially symmetric, meaning that the structure remains essentially unchanged after rotating around a central axis by any angle.

[0041] Back projection imaging refers to a radar imaging algorithm whose basic principle is to track electromagnetic waves in reverse based on their propagation time, obtain energy intensity information at each point within the imaging area, and then reconstruct the internal structure image of the target. This algorithm originates from CT imaging technology and has the advantage of high imaging resolution, but it involves a large computational load, especially in the repetitive calculation of the electromagnetic wave propagation path.

[0042] The reference detection azimuth refers to one of multiple detection azimuths selected as a benchmark. At this azimuth, traditional electromagnetic wave propagation path calculation methods are used to accurately acquire the propagation path data of all pixels within the imaging area, forming a reference path distribution, which serves as the basis for subsequent parameter reuse.

[0043] Electromagnetic wave propagation path calculation methods refer to the methods used to determine the propagation path of electromagnetic waves from the transmitting antenna to each pixel in the imaging region. This calculation needs to consider the differences in propagation speed of electromagnetic waves in different media, as well as the refraction and reflection phenomena that occur at the interface of the media, ultimately obtaining the propagation path or propagation time data.

[0044] An axisymmetric structure refers to a structure whose geometry and physical properties (such as dielectric distribution) remain unchanged after rotating around a central axis by any angle. External insulation equipment in power systems commonly possesses this characteristic, providing the structural basis for this invention to utilize angular rotation to achieve parameter reuse.

[0045] The target detection azimuth refers to the detection azimuth other than the reference detection azimuth that needs to be calculated. In this invention, the electromagnetic wave propagation path data of the target detection azimuth is not obtained by recalculation, but by rotating the reference path distribution by a corresponding angle and performing interpolation correction.

[0046] Inverse distance weighted interpolation is a spatial interpolation method. Its basic principle is that the value of an unknown point is obtained by a weighted average of the values ​​of its neighboring known points. The weight is inversely proportional to the distance between the unknown point and the known points; that is, the closer the distance, the greater the influence. In this invention, it is used to accurately obtain the propagation path data of the target pixel from the rotated path distribution to be interpolated.

[0047] Example 1: This embodiment provides a backward projection imaging method for detecting defects in external insulation equipment of power systems. This method utilizes the axisymmetric structural characteristics of external insulation equipment and reduces the repeated calculation of electromagnetic wave propagation paths by reusing parameters, thereby improving imaging efficiency.

[0048] like Figure 2 The diagram illustrates the concept of reusing electromagnetic wave propagation path parameters. External insulation equipment in power systems typically has an axisymmetric structure; for example, the insulator's skirts, sheath, and core are radially layered, with a circular cross-section. For the same external insulation equipment, when a radar antenna emits electromagnetic waves at equal detection distances, the propagation path of the electromagnetic waves reaching the measured object remains essentially unchanged. Based on this characteristic, the calculation results of the electromagnetic wave propagation path from a single detection location can be reused for other detection locations.

[0049] Specifically, such as Figure 1 As shown, the back projection imaging method includes the following steps: Step S1: Select a reference detection azimuth and calculate the reference path distribution: An arbitrary detection azimuth is selected as a reference detection azimuth. Using an electromagnetic wave propagation path calculation method, the electromagnetic wave propagation path data of each pixel within the imaging area under the reference detection azimuth is obtained, forming a reference path distribution. The electromagnetic wave propagation path data includes the electromagnetic wave propagation distance or propagation time.

[0050] Step S2: Rotate to obtain the path distribution to be interpolated: Utilizing the axisymmetric structural characteristics of the external insulation equipment of the power system, the reference path distribution is rotated by a preset angle along the axis of symmetry of the equipment under test to obtain the interpolation path distribution corresponding to the target detection orientation. The preset angle is the angular difference between the reference detection orientation and the target detection orientation.

[0051] like Figure 3 The diagram shown illustrates the process of rotating reference azimuth data and obtaining calculated azimuth data. The imaging area is assumed to be a square with an area of... The object being measured is located within this square. The reference orientation data is the original orientation. θ The propagation path distribution at 0° is set as a square with an area of ​​. In order to obtain results in each rotated figure, Greater than ( Let the reference azimuth data be rotated by an angle θ along the cylindrical coordinate direction to obtain the calculated azimuth data. Then the position in the calculated azimuth result is ( x , y , z The pixel value should be from the reference orientation position ( x’ , y’ , z’ The value is obtained from the vicinity of [location], and the calculation formula is as follows: .

[0052] Step S3: Determine the nearest reference pixel: For each target pixel at the target detection azimuth, a plurality of neighboring reference pixels are determined in the interpolation path distribution. In a preferred embodiment, the plurality of neighboring reference pixels specifically refers to the four grid pixels closest to the target pixel in the interpolation path distribution.

[0053] Step S4: Inverse distance weighted interpolation calculation: Based on the distance between the target pixel and the plurality of reference pixels, the electromagnetic wave propagation path data of the target pixel is calculated using an inverse distance weighted interpolation method.

[0054] In the case of overlap, that is, when the target pixel coincides with a reference pixel in the path distribution to be interpolated, the electromagnetic wave propagation path data of the reference pixel is directly assigned to the target pixel, such as... Figure 4 As shown.

[0055] For non-overlapping cases, it is necessary to calculate the distances from the target pixel to its four surrounding pixels, such as... Figure 5 As shown. Calculate the inverse distance weights of the four surrounding adjacent pixels, and the propagation path distance corresponding to each pixel is... , i =1, 2, 3, 4. The pixel value of the target pixel is calculated using the inverse distance-weighted algorithm, which represents the electromagnetic wave propagation path distance corresponding to this location. For example... Figure 6 As shown.

[0056] The calculation formula for the inverse distance weighted interpolation method is as follows: , In the formula, This is the electromagnetic wave propagation path data for the target pixel. The distance between the target pixel and its neighboring reference pixels. For the propagation path distance of the reference pixel, The inverse distance weight is used as the reference pixel.

[0057] Step S5: Repeat until all detection positions are covered. Repeat steps S2 to S4 until electromagnetic wave propagation path data of each pixel under all detection orientations are obtained for back projection imaging.

[0058] The method described in this embodiment significantly reduces redundant calculations and improves the overall efficiency of back projection imaging by rotating and reusing the electromagnetic wave propagation path calculation results of the reference detection azimuth to other detection azimuths.

[0059] Example 2: This embodiment provides a backward projection imaging system for detecting defects in external insulation equipment of a power system. This system is used to implement the backward projection imaging method described in Embodiment 1. The system includes: The path calculation module is used to select any detection azimuth as a reference detection azimuth, and use an electromagnetic wave propagation path calculation method to obtain the electromagnetic wave propagation path data of each pixel in the imaging area under the reference detection azimuth, forming a reference path distribution.

[0060] The rotation module is used to utilize the axisymmetric structural characteristics of the external insulation equipment of the power system to rotate the reference path distribution along the axis of symmetry of the device under test by a preset angle to obtain the interpolation path distribution corresponding to the target detection orientation.

[0061] The pixel positioning module is used to determine multiple neighboring reference pixels for each target pixel in the target detection orientation in the path distribution to be interpolated.

[0062] The interpolation calculation module is used to calculate the electromagnetic wave propagation path data of the target pixel using an inverse distance weighted interpolation method based on the distance between the target pixel and the plurality of reference pixels.

[0063] The loop control module is used to control the rotation module, pixel positioning module and interpolation calculation module to execute repeatedly until the electromagnetic wave propagation path data of each pixel under all detection orientations is obtained for back projection imaging.

[0064] Example 3: like Figure 7 As shown, this embodiment provides an electronic device, which may include: at least one processor, at least one network interface, a user interface, a memory, and at least one communication bus.

[0065] The communication bus can be used to enable communication between the various components mentioned above.

[0066] The user interface may include buttons, and optional user interfaces may also include standard wired interfaces and wireless interfaces.

[0067] The network interface may include, but is not limited to, Bluetooth modules, NFC modules, Wi-Fi modules, etc.

[0068] The processor may include one or more processing cores. It connects various parts of the electronic device via various interfaces and lines, executing instructions, programs, code sets, or instruction sets stored in memory, and accessing data stored in memory to perform various functions and process data. Optionally, the processor can be implemented using at least one hardware form of DSP, FPGA, or PLA. The processor may integrate one or more of the following: CPU, GPU, and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor.

[0069] The memory may include RAM or ROM. Optionally, the memory may include a non-transitory computer-readable medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor. The memory, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and an imaging application. The processor can be used to call the imaging application stored in the memory and execute the steps of the rear projection imaging method mentioned in the foregoing embodiments.

[0070] Example 4: This embodiment provides a computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform the above-described instructions. Figure 1 One or more steps in the illustrated embodiment. If the constituent modules of the above-described electronic device are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0071] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this specification are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Versatile Discs (DVDs)), or semiconductor media (e.g., Solid State Disks (SSDs)).

[0072] Those skilled in the art will understand that all or part of the processes in the method of Embodiment 1 described above can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and the implementation scheme can be combined arbitrarily.

[0073] Example 5: To verify the effectiveness of the back projection imaging method for detecting defects in external insulation equipment of power systems described in this specification, this embodiment conducts experimental verification based on CST simulation software. Details are as follows: Experimental setup: The object under test is a 160mm diameter ceramic cylinder, simulating the external insulation of a power system. The defect is a 5mm radius circular cavity 48mm from the axis, simulating an internal defect. During the detection process, the transmitting and receiving antennas rotate together around the axis of the object under test, maintaining constant radii and distance, with their maximum radiation direction always aligned with the center of the object. During this motion, the transmitting antenna emits electromagnetic pulses at equal intervals towards the object, and the receiving probe acquires the reflected signals, such as... Figure 8 and Figure 9 As shown, where Figure 8 For the target being measured, which has a circular cavity, Figure 9 This is a schematic diagram showing different radar detection positions.

[0074] The imaging parameters were set as follows: the imaging space had a single-side length of 200 mm, a total of 100×100 pixels, and 18 detection azimuths. The angular interval parameters for calculating the electromagnetic wave propagation path were set to 0.2°, 0.1°, 0.05°, and 0.02°, respectively, to examine the method performance under different calculation accuracy requirements.

[0075] Experimental results: When the angular interval parameter is 0.2 degrees, the back projection imaging results for all detection azimuths are calculated as follows: Figure 10 As shown, the back projection imaging result using the parameter reuse method is as follows: Figure 11 As shown in the image comparison, it can be seen that after using the parameter reuse method, the defects of the measured object can be displayed normally, and the imaging quality is basically consistent with that of the full calculation method, verifying the effectiveness of this method in ensuring imaging accuracy.

[0076] Table 1 shows a comparison of imaging time under different angle interval parameters.

[0077] Table 1:

[0078] As can be seen from the data in Table 1: The smaller the angle interval parameter, the higher the required accuracy of propagation path calculation, and the more the calculation time of traditional methods increases significantly. After using the parameter reuse method of the present invention, the calculation time is basically kept at around 39 seconds, and is not affected by the change of angle interval parameter. The percentage improvement in efficiency of parameter reuse methods increases significantly with increasing accuracy requirements, reaching up to 863.4%.

[0079] Based on the above experiments, this embodiment verifies the effectiveness of the backward projection imaging method for defect detection of external insulation equipment in power systems described in this specification. This method significantly improves computational efficiency while ensuring imaging accuracy, especially under high-precision imaging requirements, and can meet the needs of rapid on-site detection of external insulation equipment in power systems.

[0080] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0081] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0082] The above description is merely an exemplary embodiment of the present invention and should not be construed as limiting the scope of the invention. Any equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Those skilled in the art will readily conceive of embodiments of the invention upon considering the specification and practicing the disclosure herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of the invention are defined by the claims.

Claims

1. A backward projection imaging method for detecting defects in external insulation equipment of a power system, characterized in that, Including the following steps: S1. Select any detection azimuth as the reference detection azimuth, and use the electromagnetic wave propagation path calculation method to obtain the electromagnetic wave propagation path data of each pixel in the imaging area under the reference detection azimuth, and form a reference path distribution. S2. Utilizing the axisymmetric structural characteristics of the external insulation equipment of the power system, the reference path distribution is rotated by a preset angle along the axis of symmetry of the equipment under test to obtain the interpolation path distribution corresponding to the target detection orientation; S3. For each target pixel in the target detection orientation, determine its multiple neighboring reference pixels in the path distribution to be interpolated. S4. Based on the distance between the target pixel and the plurality of reference pixels, the electromagnetic wave propagation path data of the target pixel is calculated using the inverse distance weighted interpolation method. S5. Repeat steps S2 to S4 until electromagnetic wave propagation path data of each pixel under all detection orientations are obtained for back projection imaging.

2. The back projection imaging method for detecting defects in external insulation equipment of a power system according to claim 1, characterized in that: The electromagnetic wave propagation path data in step S1 includes the electromagnetic wave propagation distance or propagation time.

3. The back projection imaging method for detecting defects in external insulation equipment of a power system according to claim 1, characterized in that: In step S2, the preset angle is the angle difference between the reference detection azimuth and the target detection azimuth.

4. The back projection imaging method for detecting defects in external insulation equipment of a power system according to claim 1, characterized in that: In step S2, the imaging area of ​​the reference path distribution is smaller than the imaging area of ​​the path distribution to be interpolated.

5. A backward projection imaging method for detecting defects in external insulation equipment of a power system according to claim 1, characterized in that, In step S3, the plurality of neighboring reference pixels specifically refer to: In the path distribution to be interpolated, the four grid pixels closest to the target pixel.

6. A backward projection imaging method for detecting defects in external insulation equipment of a power system according to claim 1, characterized in that, In step S4, the calculation formula for the inverse distance weighted interpolation method is as follows: ， In the formula, This is the electromagnetic wave propagation path data for the target pixel. The distance between the target pixel and its neighboring reference pixels. For the propagation path distance of the reference pixel, The inverse distance weight is used as the reference pixel.

7. A backward projection imaging method for detecting defects in external insulation equipment of a power system according to claim 6, characterized in that: In step S4, when the target pixel coincides with a reference pixel in the path distribution to be interpolated, the electromagnetic wave propagation path data of the reference pixel is directly assigned to the target pixel.

8. A rear projection imaging system for detecting defects in external insulation equipment of a power system, characterized in that, Used to implement the back projection imaging method as described in any one of claims 1 to 7.

9. A computer device, the computer device comprising a memory, a processor, and a computer program, characterized in that, When the computer program is executed by the processor, it implements the back projection imaging method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the back projection imaging method as described in any one of claims 1 to 7.

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