Overhead wire shape estimation device and overhead wire shape estimation program
The overhead line shape estimation device and program use spline interpolation to create a Bézier curve from subdivided feature points, addressing inaccuracies in existing methods and providing precise length calculations for overhead lines.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CHUBU ELECTRIC POWER CO INC
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for creating a three-dimensional model of overhead lines using approximate quadratic curves based on three-dimensional point clouds often result in inaccurate length measurements due to the curves not exactly following the actual overhead line.
An overhead line shape estimation device and program that perform point cloud extraction, segmentation, feature point extraction, and modeling processes to create a Bézier curve through spline interpolation, using feature points from subdivided regions to accurately represent the overhead line.
The method accurately calculates the length of overhead lines by creating a three-dimensional model that closely follows the actual overhead line, enabling precise measurements.
Smart Images
Figure 2026082358000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an overhead line shape estimation device and an overhead line shape estimation program.
Background Art
[0002] When replacing an overhead line supported by a plurality of supports spaced apart such as transmission towers, the length of the overhead line is measured. However, since it is laborious to actually measure the length of the overhead line, it is conceivable to create a three-dimensional model of the overhead line using the three-dimensional coordinates of each point in the three-dimensional point cloud representing the overhead line.
[0003] For example, in Patent Document 1, an approximate quadratic curve is obtained using the least squares method based on each point in the three-dimensional point cloud representing the overhead line. Then, the obtained approximate quadratic curve is used as the three-dimensional model of the overhead line. By calculating the length of the overhead line based on the three-dimensional model of the overhead line thus created, it becomes possible to obtain the length of the overhead line without exerting labor.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In creating the three-dimensional model of the overhead line shown in Patent Document 1, the obtained approximate quadratic curve is not always exactly along the actual overhead line. Therefore, when the length of the overhead line is obtained based on the three-dimensional model, there is a possibility that the obtained length is not accurate.
Means for Solving the Problems
[0006] Next, each aspect of the overhead line counting estimation device and the overhead line shape estimation program for solving the above problems will be described. (Aspect 1) The overhead line shape estimation device comprises a control unit that targets an overhead line supported by a support and creates a three-dimensional model of the overhead line using the three-dimensional coordinates of each point in a three-dimensional point cloud representing the support, the overhead line, and their surroundings, wherein the control unit sequentially performs point cloud extraction, segmentation, feature point extraction, and modeling processes, the point cloud extraction process extracts each point representing the overhead line and its surroundings from the three-dimensional point cloud representing the support, the overhead line, and their surroundings, the segmentation process segments each point representing the overhead line from each point representing the overhead line and its surroundings extracted by the point cloud extraction process, the feature point extraction process divides each point representing the overhead line into a number of subdivided regions, finds feature points corresponding to locations in the overhead line located within the subdivided region based on each point existing within one of the subdivided regions, and obtains such feature points for each subdivided region, and the modeling process creates an approximate curve, which is a Bézier curve, through spline interpolation based on the feature points obtained for each subdivided region, and uses the approximate curve as the three-dimensional model of the overhead line.
[0007] According to the above configuration, the approximate curve, which is considered a three-dimensional model of the overhead wire, is created through spline interpolation based on feature points obtained for each of the numerous subdivided regions. The feature points used for each subdivided region correspond to points located within that region of the overhead wire. Therefore, the approximate curve obtained based on these feature points, i.e., the three-dimensional model of the overhead wire, will accurately follow the actual overhead wire. As a result, the length of the overhead wire can be accurately calculated based on the above three-dimensional model.
[0008] (Aspect 2) The overhead line shape estimation device according to Embodiment 1, wherein the modeling process creates an approximate curve, which is a Bézier curve, through spline interpolation that increases the number of feature points to increase the point density of the feature points, based on the feature points obtained for each subdivided region, and uses the approximate curve as a three-dimensional model of the overhead line.
[0009] According to the above configuration, the approximation curve, which is considered a three-dimensional model of the overhead wire, is created through spline interpolation, which increases the density of feature points obtained for each subdivided region. The approximation curve created in this way will more closely resemble the actual overhead wire.
[0010] (Aspect 3) The control unit performs a catenary length calculation process after performing the modeling process, and the catenary length calculation process calculates the length of the catenary by summing the distances between adjacent feature points on the approximation curve (Catalogous Line Shape Estimation Device according to Embodiment 2).
[0011] According to the above configuration, the length of the overhead wire can be accurately calculated based on the three-dimensional model of the created overhead wire, or more specifically, based on numerous feature points on the three-dimensional model. (Aspect 4) The overhead line shape estimation device according to any one of the embodiments (1) to (3), wherein the feature point extraction process involves rotating the entire set of points representing the overhead line around the Z axis so that the overhead line is parallel to the X and Z axes of the three-dimensional coordinate system, and then determining feature points corresponding to locations on the overhead line located within the subdivided region based on the points existing within one of the subdivided regions, and determining such feature points for each of the subdivided regions.
[0012] With the above configuration, numerous subdivided regions can be set in a two-dimensional coordinate system using the X and Z axes, making it easier to manage the feature points obtained for each of the numerous subdivided regions. (Appendix 5) The overhead wire shape estimation device according to Embodiment 4, wherein the feature point extraction process determines the centroid of each point located within one of the subdivided regions, and identifies the point closest to the centroid among the points as the feature point.
[0013] According to the above configuration, the obtained feature points will be appropriate as locations within the subdivided regions of the overhead wire. (Aspect 6) The overhead line supported by the support is an electric wire and jumper wire supported by a steel tower. The overhead line shape estimation device according to any one of (Aspect 1) to (Aspect 5).
[0014] According to the above configuration, the lengths of the power lines and jumper wires supported by the transmission tower can be accurately calculated. (Aspect 7) A program for estimating the shape of an overhead wire, which targets an overhead wire supported by a support, and creates a three-dimensional model of the overhead wire using the three-dimensional coordinates of each point in a three-dimensional point cloud representing the support, the overhead wire, and their surroundings. The process involves having a computer sequentially perform point cloud extraction, segmentation, feature point extraction, and modeling. The point cloud extraction extracts each point representing the overhead wire and its surroundings from the three-dimensional point cloud representing the support, the overhead wire, and their surroundings. The segmentation extracts each point representing the overhead wire from the points representing the overhead wire and its surroundings extracted by the point cloud extraction. The feature point extraction divides each point representing the overhead wire into numerous subdivided regions, and based on each point existing within one of the subdivided regions, finds feature points corresponding to locations on the overhead wire within the subdivided region, obtaining such feature points for each subdivided region. The modeling process creates an approximate curve, which is a Bézier curve, through spline interpolation based on the feature points obtained for each subdivided region, and uses this approximate curve as the three-dimensional model of the overhead wire.
[0015] According to the above configuration, the approximate curve, which is considered a three-dimensional model of the overhead wire, is created through spline interpolation based on feature points obtained for each of the numerous subdivided regions. The feature points used for each subdivided region correspond to points located within that region of the overhead wire. Therefore, the approximate curve obtained based on these feature points, i.e., the three-dimensional model of the overhead wire, will accurately follow the actual overhead wire. As a result, the length of the overhead wire can be accurately calculated based on the above three-dimensional model.
[0016] (Pattern 8) The modeling process creates an approximate curve that is a Bézier curve through spline interpolation that increases the number of the feature points based on the feature points obtained for each subdivision region so that the point density of the feature points increases, and sets the approximate curve as the three-dimensional model of the overhead line (as described in Aspect 7) overhead line shape estimation program.
[0017] According to the above configuration, the approximate curve that is the three-dimensional model of the overhead line is created through spline interpolation that increases the feature points obtained for each subdivision region so that the point density of the same feature points increases. The approximate curve created in this way is more in line with the actual overhead line.
[0018] (Aspect 9) After executing the modeling process, the computer executes an overhead line length calculation process, and the overhead line length calculation process calculates the length of the overhead line by summing the distances between adjacent feature points on the approximate curve (as described in Aspect 8) overhead line shape estimation program.
[0019] According to the above configuration, based on the created three-dimensional model of the overhead line, more specifically based on a large number of feature points on the three-dimensional model, the length of the overhead line can be accurately calculated. (Aspect 10) The feature point extraction process rotates the entire points representing the overhead line around the Z axis so that the overhead line is parallel to the X axis and the Z axis of the three-dimensional coordinate system, and then obtains the feature points corresponding to the locations within the subdivision region in the overhead line based on each of the points existing within one of the subdivision regions, and obtains such feature points for each of the subdivision regions (as described in any one of Aspect 7) to (Aspect 9) overhead line shape estimation program.
[0020] According to the above configuration, since a large number of subdivision regions can be set in the two-dimensional coordinate system of the X axis and the Z axis, it becomes easy to manage the feature points obtained for each of the large number of subdivision regions. (Aspect 11) The feature point extraction process obtains the centroid of each of the points existing within one of the subdivision regions, and obtains the point closest to the centroid among each of the points as the feature point (as described in Aspect 10) overhead line shape estimation program.
[0021] According to the above configuration, the required feature points are appropriate as the locations corresponding to the subdivided regions in the overhead line. (Aspect 12) The overhead line supported by the support is an overhead line shape estimation program according to any one of (Aspect 7) to (Aspect 11), which is an electric wire and a jumper wire supported by a tower.
[0022] According to the above configuration, the lengths of the electric wire and the jumper wire supported by the tower can be accurately calculated.
Brief Explanation of Drawings
[0023] [Figure 1] It is a schematic diagram showing the configuration of a computer. [Figure 2] It is a schematic diagram showing the electric wire and the jumper wire supported by the tower and their surroundings. [Figure 3] It is a flowchart showing the execution procedure of the overhead line shape estimation program executed by the computer in FIG. 1. [Figure 4] It is a perspective view showing a three-dimensional point cloud representing the electric wire and the jumper wire supported by the tower and their surroundings. [Figure 5] It is a perspective view showing each point representing the electric wire, the jumper wire, and the insulator extracted from the three-dimensional point cloud in FIG. 4. [Figure 6] It is a perspective view showing each point representing the electric wire, each point representing the jumper wire, and each point representing the insulator after noise removal for each point in FIG. 5. [Figure 7] It is a plan view showing the state of each point representing one of the plurality of overhead lines such as the electric wire and the jumper wire in FIG. 6 as viewed from the Z-axis direction of the three-dimensional coordinate system. [Figure 8] [[ID=
[40] [Figure 9] It is a side view showing the state of each point representing the overhead line in FIG. 8 as viewed from the Y-axis direction. [Figure 10] [Figure 10]This is a side view showing characteristic points obtained for each subdivided region based on each point representing the overhead wire in Figure 9. [Figure 11] This is a side view showing the approximation curve created based on the feature points for each subdivided region in Figure 10. [Figure 12] This is a perspective view showing an enlarged view of the approximation curve in Figure 11. [Modes for carrying out the invention]
[0024] An embodiment of the overhead wire shape estimation device and overhead wire shape estimation program will be described below with reference to Figures 1 to 12. The computer 11 shown in Figure 1 functions as an overhead wire shape estimation device that creates a three-dimensional model of an overhead wire supported by a support structure. The computer 11 comprises a central processing unit 12, a storage unit 13, and a communication unit 14. The central processing unit 12 controls various devices in the computer 11, such as the storage unit 13 and the communication unit 14, and performs calculations and other processing based on various data. The storage unit 13 is for storing various data. The communication unit 14 is for exchanging data with the outside of the computer 11.
[0025] The central processing unit 12 acts as a control unit that creates a three-dimensional model of the overhead wires using the three-dimensional coordinates of each point in a three-dimensional point cloud representing the support structure, the overhead wires, and their surroundings. Examples of overhead wires for which the central processing unit 12 creates a three-dimensional model include power lines and jumper wires supported by transmission towers.
[0026] Figure 2 shows a transmission tower 15 that serves as a support structure, and the overhead wires 16 and jumper wires 17 supported by the transmission tower 15. As can be seen from Figure 2, the electric wires 16 are supported by transmission towers 15 that are erected at predetermined intervals via insulators 18. The electric wires 16 are insulated from the transmission towers 15 by the insulators 18. There are two types of insulators 18: those that support the electric wires 16 between the transmission towers 15 while they are connected to each other, and those that support the electric wires 16 between the transmission towers 15 while they are insulated from each other. The jumper wires 17 are used to connect the electric wires 16 between the transmission towers 15 that are insulated by the insulators 18.
[0027] The central processing unit 12 of the computer 11 shown in Figure 1 creates a three-dimensional model of the power lines 16 and jumper wires 17 using the three-dimensional coordinates of each point in a three-dimensional point cloud representing the power lines 16 and jumper wires 17 supported by the towers 15 and their surroundings. Specifically, the central processing unit 12 executes an overhead line shape estimation program to create a three-dimensional model of the power lines 16 and jumper wires 17. This overhead line shape estimation program causes the computer 11 to sequentially execute point cloud extraction, segmentation, feature point extraction, and model creation processes in order to create the above three-dimensional model. Furthermore, after executing the above model creation process, the overhead line shape estimation program causes the computer 11 to execute an overhead line length calculation process to calculate the length of the power lines 16 between the towers 15 and the length of the jumper wires 17 based on the created three-dimensional model.
[0028] The flowchart in Figure 3 shows the execution procedure of the overhead wire shape estimation program. Figure 4 shows a three-dimensional point cloud representing the power lines 16 and jumper wires 17 supported by the transmission tower 15, as well as their surroundings. As part of step 101 (S101) in the flowchart above, the central processing unit 12 acquires the three-dimensional point cloud data representing the power lines 16 and jumper wires 17 supported by the transmission tower 15, as well as their surroundings, specifically the three-dimensional coordinates of each point in the three-dimensional point cloud. The above three-dimensional point cloud data can be acquired by laser surveying the area around the transmission tower 15 and power lines 16 using an aerial vehicle such as a drone. However, the above three-dimensional point cloud data may also be acquired by other methods.
[0029] It is conceivable that this three-dimensional point cloud data be stored in advance in the memory unit 13 of the computer 11. In this case, the central processing unit 12 retrieves the three-dimensional point cloud data from the memory unit 13. The central processing unit 12 can also directly retrieve the three-dimensional point cloud data from the aircraft via the communication unit 14. In some cases, the three-dimensional point cloud data may be stored on a server or the like. In this case, it is conceivable that the central processing unit 12 retrieves the three-dimensional point cloud data stored on the server via a network connection using the communication unit 14.
[0030] The processes S102 to S106 in the flowchart above correspond to the point cloud extraction process, classification process, feature point extraction process, model creation process, and overhead wire length calculation process, respectively. These processes will be explained individually in detail below.
[0031] <Point cloud extraction process (S102)> As part of the processing in S102, the central processing unit 12 extracts points representing the power lines 16 and jumper wires 17, as well as their surroundings, from the three-dimensional point cloud shown in Figure 4. More specifically, the central processing unit 12 classifies the three-dimensional point cloud shown in Figure 4 into points representing the transmission tower 15, points representing the power lines 16, points representing the jumper wires 17, points representing the insulators 18, and points representing the forest, etc., using semantic segmentation or the like. Subsequently, the central processing unit 12 extracts points representing the power lines 16, points representing the jumper wires 17, and points representing the insulators 18, as shown in Figure 5, from the classified points.
[0032] <Classification Processing (S103)> As part of the processing in S103, the central processing unit 12 separates the extracted points into points representing the electric wire 16, points representing the jumper wire 17, and points representing the insulator 18. Furthermore, the central processing unit 12 removes noise from each of the separated points representing the electric wire 16, points representing the jumper wire 17, and points representing the insulator 18.
[0033] In more detail, noise is removed from each point representing the divided electric wire 16 by removing points that are a predetermined distance away from a group of points representing the electric wire 16. Similarly, noise is removed from each point representing the divided jumper wire 17 by removing points that are a predetermined distance away from a group of points representing the jumper wire 17. Furthermore, noise is removed from each point representing the divided insulator 18 by removing points that are a predetermined distance away from a group of points representing the insulator 18.
[0034] Figure 6 shows the points representing the electric wire 16, the points representing the jumper wire 17, and the points representing the insulator 18 after noise reduction. The central processing unit 12 cuts out the points representing the electric wire 16 and the points representing the jumper wire 17 from these points, one wire at a time.
[0035] <Feature point extraction process (S104)> Figure 7 shows the view of each point representing one of several overhead lines, such as the power line 16 and the jumper wire 17, from the Z-axis direction of the three-dimensional coordinate system. As part of the processing in S104, the central processing unit 12 divides each point representing the overhead line into numerous subdivided regions. Specifically, the central processing unit 12 rotates all the points representing the overhead line around the Z-axis so that the overhead line is parallel to the X-axis and Z-axis of the three-dimensional coordinate system as shown in Figure 8, and then divides each point representing the overhead line into numerous subdivided regions 19 as shown in Figure 9. These numerous subdivided regions 19 are set in a two-dimensional coordinate system between the X-axis and the Z-axis.
[0036] The central processing unit 12 determines feature points 20 corresponding to locations within the subdivided region 19 of the overhead line, based on each point within that region. Specifically, the central processing unit 12 determines the centroid of each point within that region and identifies the point closest to the centroid as the feature point 20. Furthermore, the central processing unit 12 determines such feature points 20 for each of the numerous subdivided regions 19.
[0037] <Modeling process (S105)> As part of the S105 process, the central processing unit 12 creates an approximate curve, which is a Bézier curve, through spline interpolation based on the feature points 20 obtained for each subdivided region 19, as shown in Figure 10. More specifically, the central processing unit 12 creates an approximate curve 21, which is a Bézier curve, as shown in Figure 11, through cubic spline interpolation that increases the number of feature points so that the point density of the feature points increases, based on the feature points 20 obtained for each subdivided region 19. For example, the increase in the number of feature points by spline interpolation could be a tenfold increase. Furthermore, the central processing unit 12 uses the created approximate curve 21 as a three-dimensional model of the overhead wire. The central processing unit 12 performs the above-described creation of three-dimensional models for all the electric wires 16 and jumper wires 17.
[0038] <Calculation process for overhead wire length (S106)> As part of the processing in S106, the central processing unit 12 creates a three-dimensional model of the overhead wires, including the electric wires 16 and jumper wires 17, and then calculates the length of the overhead wires based on the created three-dimensional model. Figure 12 shows an approximation curve 21 which is considered to be the three-dimensional model of the overhead wires. Feature points 20, which have been multiplied tenfold by spline interpolation in the modeling process, are located on this approximation curve 21. The central processing unit 12 calculates the length of the overhead wires by summing the distances between adjacent feature points 20 on the approximation curve 21.
[0039] According to the embodiment described in detail above, the following effects and advantages can be obtained. (1) The approximate curve 21, which is considered a three-dimensional model of the overhead wires, such as the power lines 16 and jumper wires 17, is created through spline interpolation based on feature points 20 obtained for each of the numerous subdivision regions 19. The feature points 20 used for each subdivision region 19 correspond to points located within the subdivision region 19 of the overhead wire. Therefore, the approximate curve 21 obtained based on these feature points 20, i.e., the three-dimensional model of the overhead wire, will accurately follow the actual overhead wire. As a result, the length of the overhead wire can be accurately calculated based on the above three-dimensional model.
[0040] (2) The above approximation curve 21 is created by spline interpolation, where the feature points 20 obtained for each subdivided region 19 are multiplied by 10. The approximation curve 21 created in this way will more closely resemble the actual overhead wires.
[0041] (3) The length of the overhead wire is calculated based on a three-dimensional model of the overhead wire by summing the distances between adjacent feature points 20 on the approximation curve 21, which is the three-dimensional model. This allows for the accurate calculation of the length of the overhead wire based on the numerous feature points 20 on the approximation curve 21, which is the three-dimensional model of the overhead wire.
[0042] (4) When determining feature points for each of the many subdivision regions 19, the entire set of points representing the overhead wire is rotated around the Z axis so that the overhead wire is parallel to the X and Z axes of the three-dimensional coordinate system. Then, based on each point existing within one subdivision region 19, feature points 20 corresponding to the locations of the overhead wire within the subdivision region 19 are determined. Then, such feature points 20 are determined for each of the many subdivision regions 19. In this case, since the many subdivision regions 19 can be set in a two-dimensional coordinate system with the X and Z axes, it becomes easy to manage the feature points 20 determined for each of the many subdivision regions 19.
[0043] (5) The feature point 20 is determined as follows: The centroid of each point within one subdivision region 19 is determined. Furthermore, the point closest to the centroid among these points is determined as the feature point. In this case, the determined feature point 20 is appropriate as the location within the subdivision region 19 in the overhead line.
[0044] The above embodiment can also be modified as follows, for example. The above embodiment and the following modifications can be combined and implemented to the extent that they do not contradict each other technically. In the spline interpolation at S102 in Figure 3, the number of feature points was increased tenfold, but it may be increased to a value other than tenfold.
[0045] Although the overhead wires 16 and jumper wires 17 are given as examples, other types of overhead wires may also be used. Regarding the feature points 20, we determined the centroid of each point within a single subdivision region 19, and then selected the point closest to the centroid among the above points. However, it is not necessarily required that the feature points be determined in this manner.
[0046] When determining the feature points 20, it is not necessarily required to rotate all the points representing the overhead wires around the Z axis so that they are parallel to the X and Z axes of the three-dimensional coordinate system. The overhead wire shape estimation program is supposed to include overhead wire length calculation processing, but this is not necessarily required. For example, the overhead wire length calculation processing may be included in a separate program from the overhead wire shape estimation program, and the length of the overhead wire may be calculated by the separate program based on the three-dimensional model of the overhead wire created by the overhead wire shape estimation program. [Explanation of Symbols]
[0047] 11… Computer 12…Central Processing Unit 13...Storage section 14… Communications Department 15...Transmission tower 16...Electric wire 17... Jumper wire 18…Insulator 19…Subdivision area 20…Features 21…Approximate curve
Claims
1. The control unit, which targets an overhead wire supported by a support, creates a three-dimensional model of the overhead wire using the three-dimensional coordinates of each point in a three-dimensional point cloud representing the support, the overhead wire, and their surroundings, The control unit sequentially performs point cloud extraction, segmentation, feature point extraction, and modeling processes. The point cloud extraction process extracts points representing the overhead wire and its surroundings from the three-dimensional point cloud representing the support, the overhead wire and their surroundings. The aforementioned classification process involves classifying each point representing the overhead line from the points representing the overhead line and its surroundings extracted by the point cloud extraction process, The feature point extraction process divides each point representing the overhead line into a number of subdivided regions, and based on each point existing within one of the subdivided regions, it finds feature points corresponding to locations in the overhead line within the subdivided region, and obtains such feature points for each of the subdivided regions. The modeling process involves creating an approximate curve, which is a Bézier curve, through spline interpolation based on the feature points obtained for each subdivided region, and using this approximate curve as a three-dimensional model of the overhead line.
2. The overhead line shape estimation device according to claim 1, wherein the modeling process creates an approximate curve, which is a Bézier curve, through spline interpolation that increases the number of feature points based on the feature points obtained for each subdivided region so that the point density of the feature points increases, and the approximate curve is used as a three-dimensional model of the overhead line.
3. The control unit performs the overhead wire length calculation process after executing the modeling process. The overhead wire shape estimation device according to claim 2, wherein the overhead wire length calculation process calculates the length of the overhead wire by summing the distances between adjacent feature points on the approximation curve.
4. The overhead line shape estimation device according to claim 1, wherein the feature point extraction process involves rotating the entire set of points representing the overhead line around the Z axis so that the overhead line is parallel to the X and Z axes of the three-dimensional coordinate system, and then determining feature points corresponding to locations in the overhead line located within the subdivided region based on the points existing within one of the subdivided regions, and determining such feature points for each of the subdivided regions.
5. The overhead wire shape estimation device according to claim 4, wherein the feature point extraction process determines the centroid of each point located within one of the subdivided regions, and determines the point closest to the centroid among the points as the feature point.
6. The overhead line shape estimation device according to any one of claims 1 to 5, wherein the overhead line supported by the support is an electric wire and jumper wire supported by a steel tower.
7. Targeting overhead lines supported by a support, the process of creating a three-dimensional model of the overhead line using the three-dimensional coordinates of each point in a three-dimensional point cloud representing the support, the overhead line, and their surroundings involves having a computer sequentially perform point cloud extraction, segmentation, feature point extraction, and modeling processes. The point cloud extraction process extracts points representing the overhead wire and its surroundings from the three-dimensional point cloud representing the support, the overhead wire and their surroundings. The aforementioned classification process involves classifying each point representing the overhead line from the points representing the overhead line and its surroundings extracted by the point cloud extraction process, The feature point extraction process divides each point representing the overhead line into a number of subdivided regions, and based on each point existing within one of the subdivided regions, it finds feature points corresponding to locations in the overhead line within the subdivided region, and obtains such feature points for each of the subdivided regions. The aforementioned modeling process is an overhead line shape estimation program that creates an approximate curve, which is a Bézier curve, through spline interpolation based on the feature points obtained for each subdivided region, and uses this approximate curve as a three-dimensional model of the overhead line.
8. The overhead line shape estimation program according to claim 7, wherein the modeling process creates an approximate curve, which is a Bézier curve, through spline interpolation that increases the number of feature points based on the feature points obtained for each subdivided region so that the point density of the feature points increases, and the approximate curve is used as a three-dimensional model of the overhead line.
9. The aforementioned computer performs the overhead line length calculation process after performing the modeling process. The overhead wire shape estimation program according to claim 8, wherein the overhead wire length calculation process calculates the length of the overhead wire by summing the distances between adjacent feature points on the approximation curve.
10. The overhead line shape estimation program according to claim 7, wherein the feature point extraction process involves rotating the entire set of points representing the overhead line around the Z axis so that the overhead line is parallel to the X and Z axes of the three-dimensional coordinate system, and then determining feature points corresponding to locations in the overhead line located within the subdivided region based on the points existing within one of the subdivided regions, and determining such feature points for each of the subdivided regions.
11. The overhead wire shape estimation program according to claim 10, wherein the feature point extraction process determines the centroid of each point located within one of the subdivided regions, and determines the point closest to the centroid among the points as the feature point.
12. The overhead line shape estimation program according to any one of claims 7 to 11, wherein the overhead line supported by the support is an electric wire and jumper wire supported by a steel tower.