A method and system for measuring the creepage distance based on an insulator STL model

Abstract

The application provides a method and system for measuring a creeping distance based on an insulator STL model, and the method comprises the following steps: obtaining an STL model of an insulator to be measured; obtaining an axis in the STL model of the insulator to be measured, and rotating the model to a specified posture; cutting the insulator at different angles through the axis in the STL model of the insulator to obtain insulator sections at different angles; searching for an insulator section template, and determining a starting point and an ending point of the calculation of the creeping distance through template matching; and calculating the length sum of all connecting lines between the starting point and the ending point, and taking the length sum as the measured creeping distance. The application has a wide application range, high measurement precision and high measurement efficiency.

Description

Technical Field

[0001] This invention relates to the field of creepage distance measurement of insulators, and specifically to a creepage distance measurement method and system based on the STL model of insulators. Background Technology

[0002] Insulator creepage distance refers to the shortest distance or the sum of the shortest distances along the insulating surface between two parts of an insulator that are normally carrying the operating voltage.

[0003] Currently, the creepage distance of insulators is often measured by wrapping a metal wire or strip (such as black tape, transparent tape, or fiberglass cloth) around the surface of the insulator from top to bottom to replicate the shape of the insulator surface, and then measuring the length of the wire or strip. However, this traditional manual measurement requires skilled personnel, is inefficient, and has a large margin of error.

[0004] To address this problem, new measurement methods have been proposed in recent years, such as using a laser rangefinder to scan a suspension insulator along a straight line to obtain several points, then connecting these points to obtain a creepage curve, and calculating the length of the creepage curve to obtain the creepage distance. However, this method can only measure the length of one creepage curve at a time, has high requirements for the placement of the insulators, and can only measure a very limited number of insulator types.

[0005] For example, a measuring wheel was designed. By statistically analyzing the angle at which the measuring wheel rolls on the surface of the insulator, the distance the measuring wheel has rolled is calculated as the creepage distance. This requires the measuring wheel to roll on the surface of the insulator, so it cannot be used for insulators with relatively soft materials. At the same time, there are also requirements for the gap and curvature of the insulator surface; otherwise, the measuring wheel cannot roll to perform the operation.

[0006] For example, a 3D voxel mesh model of the insulator can be reconstructed using Kinect scanning, then a cross-section can be obtained by cutting along a specified plane, and finally the creepage curve length can be calculated using the edge points of the obtained cross-section. The measurement accuracy of this method is affected by the voxel resolution, and since the cutting plane is fixed, the placement of the insulator is critical. Furthermore, the creepage curve length cannot be calculated automatically and requires manual interaction. Summary of the Invention

[0007] In order to overcome the defects existing in the prior art, the purpose of this invention is to provide a creepage distance measurement method and system based on the STL model of insulators.

[0008] To achieve the above-mentioned objectives of this invention, this invention provides a creepage distance measurement method based on an insulator STL model, comprising the following steps:

[0009] Obtain the STL model of the insulator under test;

[0010] Obtain the centerline of the STL model of the insulator under test;

[0011] Cut the insulator at different angles by planes through the central axis of the STL model of the insulator to obtain insulator cross sections at different angles;

[0012] Search for insulator section templates and determine the starting and ending points for creepage distance calculation on insulator sections at different angles by template matching;

[0013] Calculate the sum of the lengths of all lines connecting the start and end points on each insulator cross section, and use this as the measured creepage distance for the corresponding insulator cross section.

[0014] In a preferred embodiment of the creepage distance measurement method based on the insulator STL model, the steps for obtaining the STL model of the insulator to be measured are as follows: the insulator is placed on a material platform, and the insulator to be measured is scanned with a scanner to obtain a preliminary insulator STL model.

[0015] The material platform was determined in the initial STL model of the insulator;

[0016] The material platform in the initial insulator STL model is removed to obtain the insulator STL model.

[0017] In a preferred embodiment of the creepage distance measurement method based on the insulator STL model, the step of determining the material platform in the preliminary insulator STL model is as follows:

[0018] From the point cloud of the initial STL model of the insulator, at least three non-coplanar points are randomly selected, and a plane is determined based on these non-coplanar points.

[0019] Count the number of points whose distance from the plane is less than a first predetermined distance;

[0020] Repeat the above steps several times, and select plane one, which has the most nearby points, as plane two.

[0021] Using all points near the second plane as input, the least squares method is used to perform plane fitting, and the material platform equation is output, thus obtaining the material platform;

[0022] The normal direction of the fitting plane is determined based on the normal of the triangular facets that make up the material platform.

[0023] In a preferred embodiment of the creepage distance measurement method based on the insulator STL model, the step of removing the material platform in the initial insulator STL model to obtain the insulator STL model is as follows:

[0024] By using the material platform equation, points on one side of the plane are selected, and a model composed of points above the material platform is obtained as the STL model of the insulator for initial screening.

[0025] Connectivity analysis was performed on the initially screened insulator STL models, and the connected component with the most points was selected as the final screened insulator STL model.

[0026] In a preferred embodiment of the creepage distance measurement method based on the insulator STL model, the steps for obtaining the axis of the insulator STL model are as follows:

[0027] Projecting points on the STL model of an insulator along a specified direction yields a two-dimensional point set So;

[0028] Given a two-dimensional point set So, first find the convex hull of the two-dimensional point set So, and then obtain the point set S1 of the convex hull;

[0029] Traverse each edge on the convex hull, and establish a new coordinate system with the direction of this edge as the x-axis direction, the midpoint as the origin, and the perpendicular direction of this edge as the y-axis direction.

[0030] Calculate the coordinates of point set S1 in the coordinate system, denoted by point set S2, and calculate the bounding box of point set S2.

[0031] Translate point set S2 so that the center point of the bounding box is located at the origin of coordinate system one, thus obtaining point set S3;

[0032] Symmetrically represent point set S3 about the x-axis to obtain point set S4. Calculate the convex hull of point set S3+S4 and the area s of the convex hull. x ;

[0033] Symmetrically represent point set S3 about the y-axis to obtain point set S5. Calculate the convex hull of point set S3+S5 and the area s of the convex hull. y ;

[0034] The s obtained from traversing each edge x and s y Select a minimum value from the set, and use the axis corresponding to that value as the axis of symmetry to be determined.

[0035] Using the specified direction as the z-axis direction, the first axis of symmetry as the x-axis direction, and the y-axis direction determined by the right-hand coordinate system, a new coordinate system two is established;

[0036] Project the points on the STL model of the insulator along the y-axis of coordinate system two to obtain the set of projected points, and determine the second axis of symmetry of the projected point set, which is the central axis of the insulator model.

[0037] In a preferred embodiment of this creepage distance measurement method based on the STL model of insulators, determining whether the centerline is accurate includes the following steps:

[0038] Project the points on the STL model of the insulator along the central axis and calculate the convex hull of the two-dimensional points after projection;

[0039] By using the least squares method to fit points on the convex hull with a circle, the center and radius of the circle can be obtained.

[0040] Calculate the IoU between the fitted circle and the convex hull of the two-dimensional points. If the IoU is greater than the set threshold, it means that the shape of the projected two-dimensional points is close to the circle, and the insulator STL model is complete. Otherwise, the insulator STL model is incomplete, and the central axis of the insulator STL model is re-determined.

[0041] In a preferred embodiment of the creepage distance measurement method based on the STL model of the insulator, the steps for obtaining the insulator cross-section at different angles are as follows:

[0042] Taking the central axis as the x-axis direction, the y-axis direction is consistent with that in coordinate system two, and the z-axis direction is determined by the right-hand coordinate system to obtain coordinate system three;

[0043] Then, from the first angle, traverse all the triangular faces on the STL model of the insulator;

[0044] Determine whether the three vertices of the triangular facet are on both sides of the xoy plane in coordinate system 3. If not, ignore the triangular facet. If so, calculate the intersection points of two of the three edges of the triangular facet with the xoy plane, save these two intersection points, and record the edge containing these two intersection points.

[0045] Combine all the points and edges obtained to form an undirected graph;

[0046] Use this undirected graph as a section at this angle;

[0047] Rotate the insulator STL model around the x-axis by a specified angle, and repeat the above steps to obtain the cross-sections at various angles.

[0048] In a preferred embodiment of the creepage distance measurement method based on the STL model of insulators, the undirected graph is repaired and denoised, and the specific steps are as follows:

[0049] The resulting undirected graph is divided into several subgraphs based on connectivity.

[0050] Determine whether the topology of each subgraph is linear and filter out non-linear subgraphs;

[0051] Select the subgraph with the longest line length from the filtered subgraphs as the initial result G;

[0052] Iterate through the two endpoints of each remaining subgraph, calculate their distances to the two endpoints of G, and find the nearest endpoint. If the distance between this endpoint and the nearest endpoint of G is less than a certain threshold, remove the subgraph and connect it to G, update the endpoints of G, and repeat the step. Otherwise, output G as the repaired and denoised undirected graph.

[0053] The repaired and denoised undirected graph is used as the cross section at that angle.

[0054] In a preferred embodiment of the creepage distance measurement method based on the insulator STL model, the steps for determining the start and end points of the creepage distance calculation are as follows:

[0055] Define template library: Obtain the cross-section of the insulator for each type of insulator, manually mark the start and end points of the creepage distance calculation, and calculate the feature vectors at the start and end points;

[0056] Obtain the cross section of the insulator to be tested, and traverse each point in the cross section to extract the feature vectors at the start and end points of the insulator to be tested using the method of calculating the feature vectors at the start and end points when defining the template library;

[0057] The extracted feature vector is compared with the feature vectors of the start and end points in the template library, and the point with the smallest difference is selected as the matching point, thereby determining the start and end points of the creepage distance calculation.

[0058] This invention also proposes a creepage distance measurement system based on an insulator STL model, comprising a data acquisition module, a processing module, and a storage module. The data acquisition module is communicatively connected to the processing module. The data acquisition module acquires the STL model of the insulator or a preliminary STL model of the insulator and sends it to the processing module. The processing module is communicatively connected to the storage module. The storage module is used to store at least one executable instruction. The executable instruction causes the processing module to perform the operation corresponding to the above-described creepage distance measurement method based on the insulator STL model, thereby obtaining the creepage distance of the insulator.

[0059] The advantages of this invention are: it is highly user-friendly, automatically outputting the length of the creepage curve (i.e., the creepage distance) of an insulator model on any cross-section based on the STL file output by a 3D scanner, without requiring additional operations. Furthermore, it does not impose many requirements on the position and orientation of the insulator in the input STL model; it only needs to be placed on a plane.

[0060] This invention has a wide range of applications and can be used for various types of insulator models, as long as the input insulator model is a body of revolution, and the insulator models encountered so far are all bodies of revolution.

[0061] This invention offers high measurement accuracy because it does not perform voxelization but directly cuts the model to obtain the cross-section. Therefore, the accuracy is mainly related to the scanning accuracy of the scanner.

[0062] This invention has high measurement efficiency. For an insulator STL model with 1 million vertices, running on an i7-8700 processor, the time from model import to analysis and output is within 20 seconds.

[0063] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0064] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0065] Figure 1 This is a flowchart illustrating the method.

[0066] Figure 2 This is a schematic diagram of an insulator STL model output by a 3D scanner;

[0067] Figure 3 This is a schematic diagram of the insulator's cross-section. Detailed Implementation

[0068] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0069] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0070] like Figure 1 As shown, this invention provides a creepage distance measurement method based on an insulator STL model, comprising the following steps:

[0071] Obtain the STL model of the insulator under test.

[0072] If there is an existing STL model of the insulator to be tested, then the next step can be performed directly based on that insulator STL model.

[0073] However, if you don't have it, you can obtain it through the following steps:

[0074] The insulator to be tested is placed on a material platform and scanned with a 3D scanner to obtain a preliminary STL model of the insulator, such as... Figure 2As shown, the preliminary STL model of the insulator is imported, that is, it is used as the input of this method to obtain the triangular facets that constitute the model. The methods involved here can all use existing methods. The preliminary STL model of the insulator mainly consists of two parts: the insulator model and the material platform model.

[0075] The material platform was determined in the initial STL model of the insulator.

[0076] Since the points constituting the material platform are almost all within a single plane and account for more than 30% of the entire STL model, and since insulators do not have large flat areas, the material platform can be obtained through RANSAC plane fitting. The specific steps are as follows:

[0077] From the point cloud of the initial STL model of the insulator, at least three non-coplanar points are randomly selected, and a plane is determined based on these non-coplanar points.

[0078] The number of points whose distance from the plane is less than a first set distance is counted; here, the first set distance is preferably, but not limited to, 10 mm.

[0079] Repeat the above steps several times, such as 1000 times, and select the plane with the most nearby points as the second plane.

[0080] Using all points near plane 2 as input, the least squares method is used to perform plane fitting, and the material platform equation is output, thus obtaining the material platform.

[0081] The normal direction of the fitting plane is determined based on the normal of the triangular facets that make up the material platform.

[0082] After determining the material platform, the material platform in the initial insulator STL model is removed to obtain the insulator STL model.

[0083] The specific steps are as follows:

[0084] By using the plane equation of the material platform, points on one side of the plane are selected, and a model composed of points above the material platform is obtained as the initial insulator STL model. Connectivity analysis is performed on the initial insulator STL model, and the connected component with the most points is selected as the final insulator STL model.

[0085] After obtaining the STL model of the insulator, obtain the central axis of the STL model of the insulator and rotate the model to the specified posture.

[0086] In this embodiment, the steps for obtaining the axis in the STL model of the insulator are as follows:

[0087] Projecting points on the STL model of the insulator along a specified direction yields a two-dimensional point set So. In this embodiment, the specified direction is preferably, but not limited to, the normal of the material platform on which the insulator is placed.

[0088] Since the STL model of an insulator is a body of revolution, and the two-dimensional point set So has a certain symmetry, the axis of symmetry is determined in the following way.

[0089] To reduce computation, the convex hull of the two-dimensional point set So is first calculated to obtain the point set S1 of the convex hull.

[0090] Traverse each edge on the convex hull, and establish a new coordinate system with the direction of this edge as the x-axis, the midpoint as the origin, and the perpendicular direction of this edge as the y-axis.

[0091] Calculate the coordinates of point set S1 in the coordinate system, denoted by point set S2, and calculate the bounding box of point set S2.

[0092] Translate point set S2 so that the center point of the bounding box is located at the origin of the coordinate system, thus obtaining point set S3.

[0093] Symmetrically represent point set S3 about the x-axis to obtain point set S4. Calculate the convex hull of point set S3+S4 and the area s of this convex hull. x .

[0094] Symmetrically represent point set S3 about the y-axis to obtain point set S5. Calculate the convex hull of point set S3+S5 and the area s of this convex hull. y .

[0095] Due to area s x s y The smaller the value, the more symmetrical the point set is about the x-axis or y-axis. Therefore, the value s obtained from traversing each edge is... x and s y In the process, select a minimum value and use the axis corresponding to that value as the axis of symmetry to be determined; here, if the minimum value is s x Then its corresponding axis of symmetry is the x-axis of coordinate system one. If the minimum value is s y Then its corresponding axis of symmetry is the y-axis of coordinate system one.

[0096] Using the aforementioned specified direction as the z-axis direction, in this embodiment, it is preferred, but not limited to, using the material platform normal as the z-axis direction, the first axis of symmetry as the x-axis direction, and the y-axis direction determined by the right-hand coordinate system to establish a new coordinate system two; project the points on the insulator STL model along the y-axis of the second coordinate system to obtain the projection point set, and determine the second axis of symmetry of the projection point set, thus obtaining the central axis of the insulator model.

[0097] Taking the second axis of symmetry, i.e. the central axis, as the new x-axis direction, and the y-axis direction as consistent with that in coordinate system two, and determining the z-axis direction through the right-hand coordinate system, we obtain coordinate system three, that is, aligning the x-axis of coordinate system three with the central axis.

[0098] After alignment, the model needs to be checked for completeness, specifically the accuracy of the centerline. Only a complete model can be used for subsequent section extraction and creepage calculations, including the following steps:

[0099] Project the points on the STL model of the insulator along the central axis and calculate the convex hull of the two-dimensional points after projection;

[0100] By using the least squares method to fit points on the convex hull with a circle, the center and radius of the circle can be obtained.

[0101] Calculate the IoU between the fitted circle and the convex hull of the two-dimensional points. If the IoU is greater than the set threshold, such as 0.75, it means that the shape of the projected two-dimensional points is close to the circle, and the insulator STL model is complete. Otherwise, the insulator STL model is incomplete, and the central axis of the insulator STL model is redefined.

[0102] After determining the central axis of the STL model of the insulator, make plane cuts at different angles through the central axis of the STL model to obtain insulator cross sections at different angles.

[0103] The cross section of the insulator STL model can be obtained by calculating the intersection of the insulator STL model with the xoy plane of coordinate system three, specifically:

[0104] In the first angle, traverse all triangular faces on the STL model of the insulator;

[0105] Determine whether the three vertices of the triangular facet are on both sides of the xoy plane in coordinate system 3. If not, ignore the triangular facet. If so, calculate the intersection points of two of the three edges of the triangular facet with the xoy plane, save these two intersection points, and record the edge containing these two intersection points.

[0106] Combine all the points and edges obtained to form an undirected graph;

[0107] Using this undirected graph as a section at that angle, such as... Figure 3 As shown;

[0108] Rotate the insulator STL model around the x-axis by a specified angle, and repeat the above steps to obtain the cross-sections at various angles.

[0109] Since the model may contain missing parts and noise, the undirected graph can be repaired and denoised. The specific steps are as follows:

[0110] The resulting undirected graph is divided into several subgraphs based on connectivity.

[0111] Determine whether the topology of each subgraph is linear and filter out non-linear subgraphs;

[0112] Select the subgraph with the longest line length from the filtered subgraphs as the initial result G;

[0113] Iterate through the two endpoints of each remaining subgraph, calculate their distances to the two endpoints of G, and find the nearest endpoint. If the distance between this endpoint and the nearest endpoint of G is less than a certain threshold, remove the subgraph and connect it to G, update the endpoints of G, and repeat the step. Otherwise, output G as the repaired and denoised undirected graph.

[0114] The repaired and denoised undirected graph is used as the cross section at that angle.

[0115] After determining the cross section, search for the insulator cross section template, and determine the start and end points for creepage distance calculation by template matching; calculate the sum of the lengths of all lines connecting the start and end points, and use this as the measured creepage distance.

[0116] In this embodiment, a template library can be predefined: obtain the cross-section of the insulator for each type of insulator, manually mark the start and end points for creepage distance calculation, and calculate the feature vectors at the start and end points.

[0117] The eigenvector is calculated as follows:

[0118] Starting from the feature point, sample uniformly along both sides of the insulator cross-section several times, such as 10 times, at a first specified length, such as 0.5 mm, to obtain the point set P1. All points on the cross-section can be considered as feature points, but the calculated feature vectors of mismatched points differ greatly. On the template curve, only the feature vectors of the manually specified start and end points need to be calculated.

[0119] Starting from the feature point, sample uniformly several times along both sides at a second specified length. The first specified length and the second specified length are different, for example, the second specified length is 2.0 mm, to obtain point set P2. Subtract the coordinates of the feature point from all points in point set P1 and point set P2, and connect them together to form a feature vector.

[0120] Obtain the cross section of the insulator to be tested, and traverse each point in the cross section as a feature point. Extract the feature vectors at the start and end points of the insulator to be tested using the method of calculating the feature vectors at the start and end points when defining the template library.

[0121] The extracted feature vectors are compared with the feature vectors of the start and end points in the template library. The point with the smallest difference is selected as the matching point, thus determining the start and end points for the creepage distance calculation. The difference can be represented by the L2 norm of the difference between the two feature vectors.

[0122] This invention also proposes a creepage distance measurement system based on an insulator STL model, which includes a data acquisition module, a processing module, and a storage module. The data acquisition module is communicatively connected to the processing module. The data acquisition module acquires the STL model of the insulator or a preliminary STL model of the insulator and sends it to the processing module. The processing module is communicatively connected to the storage module. The storage module is used to store at least one executable instruction. The executable instruction causes the processing module to perform the operation corresponding to the above-described creepage distance measurement method based on the insulator STL model to obtain the creepage distance of the insulator.

[0123] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0124] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A creepage distance measurement method based on an insulator STL model, characterized in that, Includes the following steps: Obtain the STL model of the insulator under test; The steps to obtain the centerline of the STL model of the insulator to be tested are as follows: Projecting points on the STL model of an insulator along a specified direction yields a two-dimensional point set So; Given a two-dimensional point set So, first find the convex hull of the two-dimensional point set So, and then obtain the point set S1 of the convex hull; Traverse each edge on the convex hull, and establish a new coordinate system with the direction of this edge as the x-axis direction, the midpoint as the origin, and the perpendicular direction of this edge as the y-axis direction. Calculate the coordinates of point set S1 in the coordinate system, denoted by point set S2, and calculate the bounding box of point set S2. Translate point set S2 so that the center point of the bounding box is located at the origin of coordinate system one, thus obtaining point set S3; Symmetrically represent point set S3 about the x-axis to obtain point set S4. Calculate the convex hull of point set S3+S4 and the area s of the convex hull. x ; Symmetrically represent point set S3 about the y-axis to obtain point set S5. Calculate the convex hull of point set S3+S5 and the area s of the convex hull. y ; The s obtained from traversing each edge x and s y Select a minimum value from the set, and use the axis corresponding to that value as the axis of symmetry to be determined. Using the specified direction as the z-axis direction, the first axis of symmetry as the x-axis direction, and the y-axis direction determined by the right-hand coordinate system, a new coordinate system two is established; Project the points on the STL model of the insulator along the y-axis of coordinate system two to obtain the set of projected points, and determine the second axis of symmetry of the set of projected points, which is the central axis of the insulator model. To obtain insulator cross-sections at different angles, cut planes at different angles through the central axis of the STL model of the insulator. The steps are as follows: Taking the central axis as the x-axis direction, the y-axis direction is consistent with that in coordinate system two, and the z-axis direction is determined by the right-hand coordinate system to obtain coordinate system three; Then, from the first angle, traverse all the triangular faces on the STL model of the insulator; Determine whether the three vertices of the triangular facet are on both sides of the xoy plane in coordinate system 3. If not, ignore the triangular facet. If so, calculate the intersection points of two of the three edges of the triangular facet with the xoy plane, save these two intersection points, and record the edge containing these two intersection points. Combine all the points and edges obtained to form an undirected graph; Use this undirected graph as a section at this angle; Rotate the insulator STL model around the x-axis by a specified angle, and repeat the above steps to obtain the cross-sections at various angles; Search for insulator section templates and determine the starting and ending points for creepage distance calculation on insulator sections at different angles by template matching; Calculate the sum of the lengths of all lines connecting the start and end points on each insulator cross section, and use this as the measured creepage distance for the corresponding insulator cross section.

2. The creepage distance measurement method based on the STL model of an insulator according to claim 1, characterized in that, The steps to obtain the STL model of the insulator under test are as follows: The insulator is placed on a material platform and scanned with a scanner to obtain a preliminary STL model of the insulator. The material platform was determined in the initial STL model of the insulator; The material platform in the initial insulator STL model is removed to obtain the insulator STL model.

3. The creepage distance measurement method based on the STL model of an insulator according to claim 2, characterized in that, The steps for determining the material plateau in the initial STL model of the insulator are as follows: From the point cloud of the initial STL model of the insulator, at least three non-coplanar points are randomly selected, and a plane is determined based on these non-coplanar points. Count the number of points whose distance from the plane is less than a first predetermined distance; Repeat the above steps several times, and select plane one, which has the most nearby points, as plane two. Using all points near the second plane as input, the least squares method is used to perform plane fitting, and the material platform equation is output, thus obtaining the material platform; The normal direction of the fitting plane is determined based on the normal of the triangular facets that make up the material platform.

4. The creepage distance measurement method based on the STL model of an insulator according to claim 2, characterized in that, The steps to remove the material plateau in the initial insulator STL model and obtain the insulator STL model are as follows: By using the material platform equation, points on one side of the plane are selected, and a model composed of points above the material platform is obtained as the STL model of the insulator for initial screening. Connectivity analysis was performed on the initially screened insulator STL models, and the connected component with the most points was selected as the final screened insulator STL model.

5. The creepage distance measurement method based on the STL model of an insulator according to claim 1, characterized in that, To determine if the centerline is accurate, the following steps are involved: Project the points on the STL model of the insulator along the central axis and calculate the convex hull of the two-dimensional points after projection; By using the least squares method to fit points on the convex hull with a circle, the center and radius of the circle can be obtained. Calculate the IoU between the fitted circle and the convex hull of the two-dimensional points. If the IoU is greater than the set threshold, it means that the shape of the projected two-dimensional points is close to the circle, and the insulator STL model is complete. Otherwise, the insulator STL model is incomplete, and the central axis of the insulator STL model is re-determined.

6. The creepage distance measurement method based on the STL model of an insulator according to claim 1, characterized in that, The specific steps for repairing and denoising the undirected graph are as follows: The resulting undirected graph is divided into several subgraphs based on connectivity. Determine whether the topology of each subgraph is linear and filter out non-linear subgraphs; Select the subgraph with the longest line length from the filtered subgraphs as the initial result G; Iterate through the two endpoints of each remaining subgraph, calculate their distances to the two endpoints of G, and find the nearest endpoint. If the distance between this endpoint and the nearest endpoint of G is less than a certain threshold, remove the subgraph and connect it to G, update the endpoints of G, and repeat the step. Otherwise, output G as the repaired and denoised undirected graph. The repaired and denoised undirected graph is used as the cross section at that angle.

7. The creepage distance measurement method based on the STL model of an insulator according to claim 1, characterized in that, The steps for determining the start and end points of creepage distance calculation are as follows: Define a template library: Obtain the cross-section of each type of insulator, manually mark the start and end points for creepage distance calculation, and calculate the feature vectors at the start and end points; Obtain the cross-section of the insulator to be tested, and traverse each point in the cross-section to extract the feature vectors at the start and end points of the insulator to be tested using the same method as when calculating the feature vectors at the start and end points when defining the template library; The extracted feature vector is compared with the feature vectors of the start and end points in the template library, and the point with the smallest difference is selected as the matching point, thereby determining the start and end points of the creepage distance calculation.

8. A creepage distance measurement system based on an insulator STL model, characterized in that, The system includes a data acquisition module, a processing module, and a storage module. The data acquisition module is communicatively connected to the processing module. The data acquisition module acquires an STL model or a preliminary STL model of the insulator and sends it to the processing module. The processing module is communicatively connected to the storage module. The storage module is used to store at least one executable instruction. The executable instruction causes the processing module to perform the operation corresponding to the creepage distance measurement method based on the insulator STL model as described in any one of claims 1-7, thereby obtaining the creepage distance of the insulator.

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