A method for constructing a three-dimensional spatial model for power transmission line dismantling

Abstract

The present invention discloses a method for constructing a three-dimensional spatial model for power transmission line dismantling, which belongs to the technical field of power transmission line, and specifically comprises: obtaining a target area for grid division; obtaining aerial images and point cloud data in real time from a surveying point; identifying the aerial images and marking the grid area containing the power tower image as the target grid area; if the area of ​​the area where the power tower exists is outside the standard area interval, re-surveying and obtaining a second aerial image; generating a three-dimensional model of the target area; correcting the three-dimensional model according to the second aerial image to obtain a three-dimensional real-scene model, determining the spatial range of power lines between adjacent power towers and extracting corresponding point cloud data, generating power line modeling and mapping the power line modeling to the three-dimensional real-scene model to obtain a final three-dimensional model. The present invention greatly improves the efficiency and accuracy of three-dimensional modeling of power transmission lines.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission lines, and in particular to a method for constructing a three-dimensional space model for dismantling power transmission lines. Background Art

[0002] Overhead transmission lines use power poles and towers to set up conductors in the air as channels for power transmission. Obviously, in order to improve the construction economy of overhead transmission lines and minimize the loss of electricity during transmission, direct connection paths between substations are often selected as much as possible, and the topographical impact of the line path is less considered. As a result, a large number of overhead transmission lines are built in inconvenient transportation areas such as mountainous areas and forest areas with few people, showing the characteristics of overhead lines crossing complex and diverse landforms. At the same time, with the rapid development of the national economy, the demand for electricity has further increased, and the scale of transmission lines has increased day by day. In general, the characteristics of overhead transmission lines can be mainly attributed to the large number of equipment, wide distribution, complex path topography, and being located in areas with inconvenient transportation.

[0003] As time goes by, old transmission lines may need to be replaced due to aging, backward technology or no longer meeting the current power transmission needs; or for maintenance and safety reasons, lines with safety hazards may need to be dismantled. For example, structural problems caused by natural disasters, wear or damage may threaten the safe operation of the line; due to the difficulty of manual line removal construction, low efficiency and high safety risks, the application of drones in overhead line removal in existing technologies enables the operation to be completed with higher efficiency and higher precision while ensuring the safety of operators. However, this process requires large-scale, large-scale and high-precision real-life 3D models of transmission lines. The real-life 3D model of transmission lines supports the maintenance, updating and management of transmission lines, providing detailed information support, making the dismantling process more scientific, reasonable and safe. By combining drone technology and 3D modeling technology, the automation level of transmission line dismantling can be significantly improved, labor costs can be reduced, and work efficiency and safety can be improved, thereby effectively addressing the shortcomings of traditional line removal methods.

[0004] In the prior art, oblique photography technology is usually used to construct real-life 3D models of power transmission lines. However, facing the actual situation that overhead power transmission lines are mostly distributed in mountainous and forested areas with large terrain undulations and complex surface conditions, how to ensure the efficiency and accuracy of 3D modeling of power transmission lines is a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a method for constructing a three-dimensional space model for power transmission line dismantling, so as to solve the following technical problems:

[0006] In the prior art, oblique photography technology is usually used to construct real-life 3D models of power transmission lines. However, facing the actual situation that overhead power transmission lines are mostly distributed in mountainous and forested areas with large terrain undulations and complex surface conditions, how to ensure the efficiency and accuracy of 3D modeling of power transmission lines is a technical problem that technicians in this field need to solve urgently.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for constructing a three-dimensional space model for power transmission line dismantling comprises the following steps:

[0009] S1, obtaining a route map of the power transmission line and determining the target area according to the transmission line map, obtaining the target area and dividing it into grids to generate a number of grid areas; defining the center point of the wide side of any grid area as a surveying point, taking the line connecting two surveying points in the same grid area as the planned route of the UAV, controlling the UAV to start from the surveying point at a first altitude, and fly along the planned route and obtain aerial images and point cloud data in real time; the first altitude is the flight altitude of the UAV under the minimum target accuracy;

[0010] S2, perform power tower identification on all aerial images. If the identification result is that the aerial image contains a power tower image, mark the grid area containing the power tower image as the target grid area; preset the standard area interval of the power tower [f, g], intercept a minimum circumscribed rectangle covering all power tower areas from the target grid area and calculate the area S of the minimum circumscribed rectangle. If S belongs to [f, g], control the drone to survey the next grid area along the current surveying route; if S does not belong to [f, g], adjust the flight altitude of the drone to a second altitude to re-survey the target grid area to obtain a second aerial image and a second point cloud data;

[0011] S3, respectively processing the aerial images corresponding to different grid areas to obtain orthophotos of all grid areas and generate a three-dimensional model of the target area; correcting the three-dimensional model according to the second aerial image to obtain a three-dimensional real-scene model, determining the spatial range of power lines between adjacent power towers according to the three-dimensional real-scene model and extracting point cloud data within the spatial range, generating power line modeling according to the point cloud data and mapping the power line modeling to the three-dimensional real-scene model to obtain a final three-dimensional model.

[0012] As a further solution of the present invention: in S1, the drone randomly selects a grid area for surveying and mapping, and the same surveying point can only be used as a starting point for one drone.

[0013] As a further solution of the present invention: In S2, the specific process of identifying the power tower is as follows:

[0014] S11, grayscale processing is performed on the aerial image to obtain a grayscale image, edge extraction is performed on the grayscale image, and then straight line features of the image are extracted based on the edge feature extraction, and the line features are simplified using the Douglas–Peucker algorithm;

[0015] S12, select any straight line segment and calculate the length and direction of the straight line segment, obtain the length and direction of all straight line segments, obtain all straight line segments in the preset direction interval [0, 180], divide the preset direction interval into several sub-direction intervals according to the preset step size, and calculate the straight line eigenvalue P in any sub-direction interval in turn. ; Wherein, m is the number of straight lines in sub-direction interval j, n is the number of all sub-direction intervals, qi is the length of any straight line segment; if there is a straight line feature value P in any sub-direction interval that is greater than a preset threshold, then the sub-direction interval is marked as a target direction interval; the direction difference between the target direction intervals is calculated, and if there is a direction difference of 90 degrees, then the target direction interval is marked as a vertical interval, and the number of all vertical intervals N is obtained;

[0016] S13, calculate the tower coefficient A. If the tower coefficient A of any aerial image is greater than a preset threshold, it is determined that there is a power tower image in the aerial image; tower coefficient A = (1+N)*P0; N is the number of vertical intervals, and P0 represents the directional characteristic value of the 0 interval.

[0017] As a further solution of the present invention: in S2, the specific calculation process of the second height is:

[0018] Obtain the minimum circumscribed rectangular area S of the power tower area, calculate the difference △S between S and (f+g) / 2, and calculate the second flight height H' according to the calculation formula H'=H*(S+△S) / S, where H is the first flight height.

[0019] As a further solution of the present invention: in S2, the process of generating the three-dimensional model is:

[0020] The aerial image is grayed to obtain a gray image, the gray image is denoised and Harris corner detection is used to extract feature points in the gray image, the feature points of the gray image are matched using a nearest neighbor matching algorithm to establish a correspondence between images, and the gray image is subjected to aerial triangulation to obtain coordinate information of the aerial image, and the pre-processed aerial images are spliced ​​according to the obtained coordinate information to obtain a three-dimensional model of the area to be surveyed.

[0021] As a further solution of the present invention: in S3, the specific process of correction is:

[0022] Each grid area corresponds to a grid number and is not repeated, the numbers of all target grid areas are obtained, the orthophoto image of the grid area with the corresponding number in the three-dimensional model is replaced with the second aerial image, and the orthophoto image and the second aerial image are respectively decomposed into a Gaussian pyramid and a Laplace pyramid to obtain Gaussian pyramids and Laplace pyramids of the two images; wherein the Gaussian pyramid has N+1 layers, and the Laplace pyramid has N layers; an N+1-layer Gaussian pyramid is established using a preset binary mask; each binary mask in the N+1-layer Gaussian pyramid established with the binary mask is used as a weight, and the corresponding layers of the Laplace pyramid of the orthophoto image and the second aerial image are added to obtain a first pyramid; the N+1th layer of the Gaussian pyramid of the aerial image and the second aerial image is added to obtain a first fused image; and the first fused image is used to reconstruct the first pyramid to obtain a three-dimensional real scene model.

[0023] As a further solution of the present invention: in S3, the specific process of the power line space range is:

[0024] Obtain information of any adjacent power tower, the power tower information including the minimum circumscribed rectangle of the power tower and the geometric center point of the power tower, respectively construct a first straight line segment passing through the geometric center point of the power tower and parallel to the longest side of the minimum circumscribed rectangle for any power tower, the midpoint of the first straight line segment coincides with the geometric midpoint of the power tower, obtain the corresponding first straight line segment of any power tower and connect the endpoints of the first straight line segments of adjacent power towers in a clockwise direction in sequence to generate a midpoint two-dimensional plane;

[0025] Get the vertex of any power tower and construct a second straight line segment passing through the vertex and parallel to the corresponding straight line segment of the power tower, the midpoint of the second straight line segment coincides with the vertex and the length is equal to the length of the first straight line segment, connect the endpoints of the second straight line segments of adjacent power towers in sequence in a clockwise direction, generate a vertex two-dimensional plane, construct a spatial matrix with the midpoint two-dimensional plane as the bottom surface and the vertex two-dimensional plane as the top surface, and calibrate the volume of the spatial matrix as the spatial range of the power line.

[0026] As a further solution of the present invention: in S3, the specific process of power line modeling is:

[0027] Extract all point cloud data within the spatial range, select the point corresponding to the minimum x-coordinate value in the point cloud data as the core point and set the clustering control radius R, construct a straight line passing through the core point and parallel to the short side of the vertex two-dimensional plane and determine the direction of the straight line to be along the direction of the adjacent power tower as the positive direction, take the core point as the center of the sphere and R as the radius of the sphere to scan along the positive direction of the straight line and determine whether new point cloud data is scanned each time. If so, store the scanned point cloud data in the set Y, and update the core point to the point corresponding to the maximum x-coordinate value in the set Y; if not, continue to scan along the positive direction of the straight line; repeat the above steps and generate sets Y1, Y2, ..., Yn, obtain all the point cloud data in any set Yi, fit the point cloud data according to the preset parabola model, and obtain any three-dimensional model of power lines.

[0028] Beneficial effects of the present invention:

[0029] The present invention performs grid processing on the target area, plans the surveying route based on the grid, obtains aerial images in real time, and determines the coverage of the power towers in the grid area through the tower recognition technology, marks the grid area containing the power tower image as the target grid area, obtains the area of ​​the power tower area in the target grid area, and re-surveys the target grid area based on the area of ​​the power tower area. By processing aerial images of different grid areas, the orthophotos and three-dimensional models of all grid areas in the target area are obtained, and then the three-dimensional model is corrected according to the orthophotos of the target grid area to obtain a three-dimensional real scene model, and the spatial range of the power lines between adjacent power towers is determined according to the three-dimensional real scene model, and point cloud data of the corresponding spatial range is extracted, and power line modeling is generated according to the point cloud data, and the power line modeling is mapped to the three-dimensional real scene model to obtain the final three-dimensional model. The present invention greatly improves the efficiency and accuracy of three-dimensional modeling of transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] Figure 1 The present invention is a schematic flow chart of a method for constructing a three-dimensional space model for dismantling a power transmission line. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1As shown, the present invention is a method for constructing a three-dimensional space model for power transmission line dismantling, comprising the following steps:

[0034] S1, obtaining a route map of the power transmission line and determining the target area according to the transmission line map, obtaining the target area and dividing it into grids to generate a number of grid areas; defining the center point of the wide side of any grid area as a surveying point, taking the line connecting two surveying points in the same grid area as the planned route of the UAV, controlling the UAV to start from the surveying point at a first altitude, and fly along the planned route and obtain aerial images and point cloud data in real time; the first altitude is the flight altitude of the UAV under the minimum target accuracy;

[0035] S2, perform power tower identification on all aerial images. If the identification result is that the aerial image contains a power tower image, mark the grid area containing the power tower image as the target grid area; preset the standard area interval of the power tower [f, g], intercept a minimum circumscribed rectangle covering all power tower areas from the target grid area and calculate the area S of the minimum circumscribed rectangle. If S belongs to [f, g], control the drone to survey the next grid area along the current surveying route; if S does not belong to [f, g], adjust the flight altitude of the drone to a second altitude to re-survey the target grid area to obtain a second aerial image and a second point cloud data;

[0036] S3, respectively processing the aerial images corresponding to different grid areas to obtain orthophotos of all grid areas and generate a three-dimensional model of the target area; correcting the three-dimensional model according to the second aerial image to obtain a three-dimensional real-scene model, determining the spatial range of power lines between adjacent power towers according to the three-dimensional real-scene model and extracting point cloud data within the spatial range, generating power line modeling according to the point cloud data and mapping the power line modeling to the three-dimensional real-scene model to obtain a final three-dimensional model.

[0037] The present invention performs grid processing on the target area, plans the surveying route based on the grid, obtains aerial images in real time, and determines the coverage of the power towers in the grid area through the tower recognition technology, marks the grid area containing the power tower image as the target grid area, obtains the area of ​​the power tower area in the target grid area, and re-surveys the target grid area based on the area of ​​the power tower area. By processing aerial images of different grid areas, the orthophotos and three-dimensional models of all grid areas in the target area are obtained, and then the three-dimensional model is corrected according to the orthophotos of the target grid area to obtain a three-dimensional real scene model, and the spatial range of the power lines between adjacent power towers is determined according to the three-dimensional real scene model, and point cloud data of the corresponding spatial range is extracted, and power line modeling is generated according to the point cloud data, and the power line modeling is mapped to the three-dimensional real scene model to obtain the final three-dimensional model. The present invention greatly improves the efficiency and accuracy of three-dimensional modeling of transmission lines.

[0038] It is worth noting that in order to improve the construction economy of overhead transmission lines and minimize the loss of electric energy during transmission, overhead transmission lines are usually located in mountainous and forested areas with large terrain undulations and complex surface conditions. As a result, when no one is mapping the transmission lines, the actual aerial image resolutions are also very different due to the different terrain positions of each power tower. When modeling through oblique photography technology, the large difference in resolution between the aerial images corresponding to each tower will lead to modeling model details loss, geometric deformation, and texture mapping errors. In the power industry, the removal of transmission lines is a critical and high-risk task. Traditional two-dimensional design is often difficult to meet the needs of removal due to the lack of three-dimensional sense and spatial information. Accurate three-dimensional transmission line modeling can overcome these difficulties and bring many advantages to the removal of lines. Three-dimensional modeling can provide all-round views and data support. By constructing an accurate three-dimensional model, workers can observe the various components of the transmission line from different angles, including power towers, conductors, insulators, etc. This three-dimensional perspective helps to more intuitively understand the layout and potential danger points of the line, so as to make adequate preparations before removal. During the wire removal process, workers need to come into contact with high-voltage power equipment and also have to deal with the risks brought by high-altitude operations. Through accurate three-dimensional models, workers can identify and avoid dangerous areas in advance and develop safer and more reasonable wire removal plans. For example, the three-dimensional model can accurately measure the distance and height between power towers to ensure that a sufficient safe distance is maintained during the wire removal process. Traditional wire removal methods usually rely on manual surveys and measurements, which are not only time-consuming and labor-intensive, but also prone to errors. With accurate three-dimensional models, workers can optimize the wire removal steps and paths through simulation and data analysis. For example, the three-dimensional model can calculate the shortest wire removal path and the optimal removal order, thereby reducing unnecessary actions and time waste. Therefore, the model error caused by the large difference in resolution between images may make the spatial analysis results inaccurate, thereby affecting the final line insertion decision and planning. Therefore, in the present invention, by presetting the standard area interval [f, g] of the power tower, a minimum circumscribed rectangle covering all power tower areas is intercepted from the target grid area and the area S of the minimum circumscribed rectangle is calculated. If S belongs to [f, g], the drone is controlled to survey the next grid area along the current surveying route; if S does not belong to [f, g], the flight altitude of the drone is adjusted to a second altitude to re-survey the target grid area to obtain a second aerial image, so as to ensure that the difference in aerial image resolution between each power tower is less than the preset threshold, thereby ensuring the accuracy of modeling.

[0039] In a preferred embodiment of the present invention, in S1, the drone randomly selects a grid area for surveying and mapping, and the same surveying point can only be used as a starting point for one drone.

[0040] In another preferred embodiment of the present invention, in S2, the specific process of identifying the power tower is:

[0041] S11, grayscale processing is performed on the aerial image to obtain a grayscale image, edge extraction is performed on the grayscale image, and then straight line features of the image are extracted based on the edge feature extraction, and the line features are simplified using the Douglas–Peucker algorithm;

[0042] S12, select any straight line segment and calculate the length and direction of the straight line segment, obtain the length and direction of all straight line segments, obtain all straight line segments in the preset direction interval [0, 180], divide the preset direction interval into several sub-direction intervals according to the preset step size, and calculate the straight line eigenvalue P in any sub-direction interval in turn. ; Wherein, m is the number of straight lines in sub-direction interval j, n is the number of all sub-direction intervals, qi is the length of any straight line segment; if there is a straight line feature value P in any sub-direction interval that is greater than a preset threshold, then the sub-direction interval is marked as a target direction interval; the direction difference between the target direction intervals is calculated, and if there is a direction difference of 90 degrees, then the target direction interval is marked as a vertical interval, and the number of all vertical intervals N is obtained;

[0043] S13, calculate the tower coefficient A. If the tower coefficient A of any aerial image is greater than a preset threshold, it is determined that there is a power tower image in the aerial image; tower coefficient A = (1+N)*P0; N is the number of vertical intervals, and P0 represents the directional characteristic value of the 0 interval.

[0044] First, detect the edge in the image. On the basis of edge extraction, further extract the straight line features in the image. In order to reduce the amount of calculation and improve accuracy, the Douglas-Peucker algorithm is used to simplify the detected line segments. The algorithm can eliminate those points that are not the main part of the straight line. For each straight line segment, calculate its length and direction, divide all directions into a preset interval [0, 180], and further subdivide them into several sub-direction intervals according to the preset step size. For each sub-direction interval, calculate an eigenvalue P; this eigenvalue is based on the length and number of straight line segments in the interval. If the eigenvalue P of a sub-direction interval is greater than the preset threshold, it means that the straight line feature of the sub-interval is the main body. Check the direction difference between the target direction intervals. If there is a 90-degree difference, it is marked as a vertical interval. For the area where the power tower exists, there is usually long straightness. Therefore, the P0 value is used to measure the building coefficient. The calculation of the power tower coefficient can accurately determine whether the image is a power tower image area.

[0045] In another preferred embodiment of the present invention, in S2, the specific calculation process of the second height is:

[0046] Obtain the minimum circumscribed rectangular area S of the power tower area, calculate the difference △S between S and (f+g) / 2, and calculate the second flight height H' according to the calculation formula H'=H*(S+△S) / S, where H is the first flight height.

[0047] In another preferred embodiment of the present invention, in S3, the process of generating the three-dimensional model is:

[0048] The aerial image is grayed to obtain a gray image, the gray image is denoised and Harris corner detection is used to extract feature points in the gray image, the feature points of the gray image are matched using a nearest neighbor matching algorithm to establish a correspondence between images, and the gray image is subjected to aerial triangulation to obtain coordinate information of the aerial image, and the pre-processed aerial images are spliced ​​according to the obtained coordinate information to obtain a three-dimensional model of the area to be surveyed.

[0049] In another preferred embodiment of the present invention, in S3, the specific process of correction is:

[0050] Each grid area corresponds to a grid number and is not repeated, the numbers of all target grid areas are obtained, the orthophoto image of the grid area with the corresponding number in the three-dimensional model is replaced with the second aerial image, and the orthophoto image and the second aerial image are respectively decomposed into a Gaussian pyramid and a Laplace pyramid to obtain Gaussian pyramids and Laplace pyramids of the two images; wherein the Gaussian pyramid has N+1 layers, and the Laplace pyramid has N layers; an N+1-layer Gaussian pyramid is established using a preset binary mask; each binary mask in the N+1-layer Gaussian pyramid established with the binary mask is used as a weight, and the corresponding layers of the Laplace pyramid of the orthophoto image and the second aerial image are added to obtain a first pyramid; the N+1th layer of the Gaussian pyramid of the aerial image and the second aerial image is added to obtain a first fused image; and the first fused image is used to reconstruct the first pyramid to obtain a three-dimensional real scene model.

[0051] By replacing and fusing the 3D model, the orthophoto map of the target grid area can be fused with the corresponding grid area in the initial vegetation area map to obtain more refined terrain data. This helps to improve the precision and accuracy of the topographic map and provide a more reliable data basis for subsequent terrain analysis and application. By numbering each grid area, data management and processing can be conveniently performed. When performing replacement and fusion, the target grid area can be quickly located and processed based on the numbering information. The program automatically obtains the numbers of all target grid areas and performs replacement and fusion processing, which can greatly improve the processing efficiency of surveying and mapping data and avoid the tediousness and errors of manual operations.

[0052] In another preferred embodiment of the present invention, in S3, the specific process of the power line space range is:

[0053] Obtain information of any adjacent power tower, the power tower information including the minimum circumscribed rectangle of the power tower and the geometric center point of the power tower, respectively construct a first straight line segment passing through the geometric center point of the power tower and parallel to the longest side of the minimum circumscribed rectangle for any power tower, the midpoint of the first straight line segment coincides with the geometric midpoint of the power tower, obtain the corresponding first straight line segment of any power tower and connect the endpoints of the first straight line segments of adjacent power towers in a clockwise direction in sequence to generate a midpoint two-dimensional plane;

[0054] Get the vertex of any power tower and construct a second straight line segment passing through the vertex and parallel to the corresponding straight line segment of the power tower, the midpoint of the second straight line segment coincides with the vertex and the length is equal to the length of the first straight line segment, connect the endpoints of the second straight line segments of adjacent power towers in sequence in a clockwise direction, generate a vertex two-dimensional plane, construct a spatial matrix with the midpoint two-dimensional plane as the bottom surface and the vertex two-dimensional plane as the top surface, and calibrate the volume of the spatial matrix as the spatial range of the power line.

[0055] It can be understood that in the XOY plane, each power tower corresponds to a minimum circumscribed rectangle and its geometric center point. The shape of the power tower is a rectangle with its short side basically consistent with the direction of the power line and its long side basically perpendicular to the direction of the power line. At the same time, the suspension point of the power line is usually located near the center line of the rectangle. In order to obtain the optimal boundary of the power line lidar point, it is necessary to divide the power line lidar points on the left and right sides of each power tower, with the corresponding minimum circumscribed rectangle geometric center point as the center, and extend the length C to both sides. In this way, each power tower corresponds to a straight line segment, which is approximately perpendicular to the direction of the power line. Then, the endpoints of the straight line segments involving the two power towers are connected in turn in a clockwise direction to form a quadrilateral. This quadrilateral is the two-dimensional spatial range of the lowest distribution of the power line. At the same time, the height of the hanging point of the power line will not exceed the vertex of the tower. Therefore, the vertex of any power tower is obtained and a second straight line segment passing through the vertex and parallel to the straight line segment corresponding to the power tower is constructed. A vertex two-dimensional plane is generated according to the second straight line segment, and a spatial matrix is ​​constructed with the midpoint two-dimensional plane as the bottom surface and the vertex two-dimensional plane as the top surface, and the volume of the spatial matrix is ​​calibrated as the spatial range of the power line.

[0056] In another preferred embodiment of the present invention, in S3, the specific process of power line modeling is:

[0057] Extract all point cloud data within the spatial range, select the point corresponding to the minimum x-coordinate value in the point cloud data as the core point and set the clustering control radius R, construct a straight line passing through the core point and parallel to the short side of the vertex two-dimensional plane and determine the direction of the straight line to be along the direction of the adjacent power tower as the positive direction, take the core point as the center of the sphere and R as the radius of the sphere to scan along the positive direction of the straight line and determine whether new point cloud data is scanned each time. If so, store the scanned point cloud data in the set Y, and update the core point to the point corresponding to the maximum x-coordinate value in the set Y; if not, continue to scan along the positive direction of the straight line; repeat the above steps and generate sets Y1, Y2, ..., Yn, obtain all the point cloud data in any set Yi, fit the point cloud data according to the preset parabola model, and obtain any three-dimensional model of power lines.

[0058] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for constructing a three-dimensional space model for power transmission line dismantling, characterized in that: The following steps are involved: S1, obtaining a route map of the power transmission line and determining the target area according to the transmission line map, obtaining the target area and dividing it into grids to generate a number of grid areas; defining the center point of the wide side of any grid area as a surveying point, taking the line connecting two surveying points in the same grid area as the planned route of the UAV, controlling the UAV to start from the surveying point at a first altitude, and fly along the planned route and obtain aerial images and point cloud data in real time; the first altitude is the flight altitude of the UAV under the minimum target accuracy; S2, performing power tower identification on all aerial images, if the identification result is that the aerial image contains a power tower image, marking the grid area containing the power tower image as the target grid area; The area interval of the standard area of ​​the power tower is preset [f, g], then a minimum circumscribed rectangle covering all power tower areas is intercepted from the target grid area and the area S of the minimum circumscribed rectangle is calculated. If S belongs to [f, g], the drone is controlled to survey the next grid area along the current surveying route; if S does not belong to [f, g], the flight altitude of the drone is adjusted to a second altitude to re-survey the target grid area to obtain a second aerial image; S3, respectively processing the aerial images corresponding to different grid areas to obtain orthophotos of all grid areas and generate a three-dimensional model of the target area; correcting the three-dimensional model according to the second aerial image to obtain a three-dimensional real scene model, determining the spatial range of power lines between adjacent power towers according to the three-dimensional real scene model and extracting point cloud data within the spatial range, generating power line modeling according to the point cloud data and mapping the power line modeling to the three-dimensional real scene model to obtain a final three-dimensional model; The specific process of power line modeling is: Get the vertex of any power tower and construct a second straight line segment passing through the vertex and parallel to the corresponding straight line segment of the power tower. The midpoint of the second straight line segment coincides with the vertex and the length is equal to the length of the first straight line segment. Connect the endpoints of the second straight line segments of adjacent power towers in a clockwise direction to generate a vertex two-dimensional plane. Extract all point cloud data within the spatial range, select the point corresponding to the minimum x-coordinate value in the point cloud data as the core point and set the clustering control radius R. Construct a straight line passing through the core point and parallel to the short side of the vertex two-dimensional plane and determine the direction of the straight line to follow the adjacent The direction of the power tower is the positive direction, and the core point is taken as the center of the sphere and R is the radius of the sphere to scan along the positive direction of the straight line and determine whether new point cloud data is scanned each time. If so, the scanned point cloud data is stored in the set Y, and the core point is updated to the point corresponding to the maximum x coordinate value in the set Y; if not, continue to scan along the positive direction of the straight line; repeat the above steps and generate sets Y1, Y2, ..., Yn, obtain all the point cloud data in any set Yi, fit the point cloud data according to the preset parabola model, and obtain any three-dimensional model of the power line.

2. A method for constructing a three-dimensional space model for power transmission line dismantling according to claim 1, characterized in that: In S1, the drone randomly selects a grid area for surveying and mapping, and the same surveying point can only be used as the starting point of one drone.

3. A method for constructing a three-dimensional space model for power transmission line dismantling according to claim 1, characterized in that: In S2, the specific process of identifying the power tower is as follows: S11, grayscale processing is performed on the aerial image to obtain a grayscale image, edge extraction is performed on the grayscale image, and then straight line features of the image are extracted based on the edge feature extraction, and the line features are simplified using the Douglas–Peucker algorithm; S12, select any straight line segment and calculate the length and direction of the straight line segment, obtain the length and direction of all straight line segments, obtain all straight line segments in the preset direction interval [0, 180], divide the preset direction interval into several sub-direction intervals according to the preset step size, and calculate the straight line eigenvalue P in any sub-direction interval in turn. ; Wherein, m is the number of straight lines in sub-direction interval j, n is the number of all sub-direction intervals, qi is the length of any straight line segment; if there is a straight line feature value P in any sub-direction interval that is greater than a preset threshold, then the sub-direction interval is marked as a target direction interval; the direction difference between the target direction intervals is calculated, and if there is a direction difference of 90 degrees, then the target direction interval is marked as a vertical interval, and the number of all vertical intervals N is obtained; S13, calculate the tower coefficient A. If the tower coefficient A of any aerial image is greater than a preset threshold, it is determined that there is a power tower image in the aerial image; tower coefficient A = (1+N)*P0; N is the number of vertical intervals, and P0 represents the directional characteristic value of the 0 interval.

4. A method for constructing a three-dimensional space model for power transmission line dismantling according to claim 1, characterized in that: In S2, the specific calculation process of the second height is: Obtain the minimum circumscribed rectangular area S of the power tower area, calculate the difference △S between S and (f+g) / 2, and calculate the second flight height H' according to the calculation formula H'=H*(S+△S) / S, where H is the first flight height.

5. A method for constructing a three-dimensional space model for power transmission line dismantling according to claim 1, characterized in that: In S3, the generation process of the three-dimensional model is as follows: The aerial image is grayed to obtain a gray image, the gray image is denoised and Harris corner detection is used to extract feature points in the gray image, the feature points of the gray image are matched using a nearest neighbor matching algorithm to establish a correspondence between images, and the gray image is subjected to aerial triangulation to obtain coordinate information of the aerial image, and the pre-processed aerial images are spliced ​​according to the obtained coordinate information to obtain a three-dimensional model of the area to be surveyed.

6. A method for constructing a three-dimensional space model for power transmission line dismantling according to claim 1, characterized in that: In S3, the specific process of correction is: Each grid area corresponds to a grid number and is not repeated, the numbers of all target grid areas are obtained, the orthophoto image of the grid area with the corresponding number in the three-dimensional model is replaced with the second aerial image, and the orthophoto image and the second aerial image are respectively decomposed into a Gaussian pyramid and a Laplace pyramid to obtain Gaussian pyramids and Laplace pyramids of the two images; wherein the layer of the Gaussian pyramid is the Z+1 layer, and the layer of the Laplace pyramid is the Z layer; the Z+1-layer Gaussian pyramid is established by using a preset binary mask; each layer of the binary mask in the Z+1-layer Gaussian pyramid established by the binary mask is used as a weight, and the corresponding layers of the Laplace pyramid of the orthophoto image and the second aerial image are added to obtain a first pyramid; the Z+1-th layer of the Gaussian pyramid of the aerial image and the second aerial image is added to obtain a first fused image; the first fused image is used to reconstruct the first pyramid to obtain a three-dimensional real scene model.

7. A method for constructing a three-dimensional space model for power transmission line dismantling according to claim 1, characterized in that: In S3, the specific process of the power line space range is: Obtain information of any adjacent power tower, the power tower information including the minimum circumscribed rectangle of the power tower and the geometric center point of the power tower, respectively construct a first straight line segment passing through the geometric center point of the power tower and parallel to the longest side of the minimum circumscribed rectangle for any power tower, the midpoint of the first straight line segment coincides with the geometric midpoint of the power tower, obtain the corresponding first straight line segment of any power tower and connect the endpoints of the first straight line segments of adjacent power towers in a clockwise direction in sequence to generate a midpoint two-dimensional plane; Get the vertex of any power tower and construct a second straight line segment passing through the vertex and parallel to the corresponding straight line segment of the power tower, the midpoint of the second straight line segment coincides with the vertex and the length is equal to the length of the first straight line segment, connect the endpoints of the second straight line segments of adjacent power towers in sequence in a clockwise direction, generate a vertex two-dimensional plane, construct a spatial matrix with the midpoint two-dimensional plane as the bottom surface and the vertex two-dimensional plane as the top surface, and calibrate the volume of the spatial matrix as the spatial range of the power line.

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