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CN-122023683-A - Three-dimensional vector element extraction method of power transmission line based on laser point cloud

CN122023683ACN 122023683 ACN122023683 ACN 122023683ACN-122023683-A

Abstract

The invention belongs to the technical field of three-dimensional vector element extraction of a power transmission line, and particularly relates to a three-dimensional vector element extraction method of the power transmission line based on laser point clouds, which is used for carrying out height threshold filtering on original laser point clouds, removing ground points, low vegetation and Cheng Zaosheng points, and reserving related point clouds of an overhead structure; the method comprises the steps of projecting filtered point clouds to an XY plane, identifying tower point clusters by adopting a density-based clustering method, calculating mass center coordinates of each tower point cluster on the XY plane, removing the tower point clusters to obtain a point cloud subset only containing wires, constructing a minimum spanning tree by taking the tower mass centers as nodes, taking tree edges as transmission line spans, classifying the wire point clouds into corresponding spans according to the nearest tree edges, and dividing left and right wire point sets based on orthogonal projection of the main directions of the spans.

Inventors

  • ZHONG SHAOBO
  • Yue Zichen
  • HU HAIFENG

Assignees

  • 北京市科学技术研究院

Dates

Publication Date
20260512
Application Date
20251113

Claims (10)

  1. 1. A method for extracting three-dimensional vector elements of a power transmission line based on laser point cloud is characterized by comprising the following steps: filtering the original laser point cloud by a height threshold value, removing ground points, low vegetation and low Cheng Zaosheng points, and reserving related point clouds of an overhead structure; projecting the filtered point cloud to an XY plane, identifying tower point clusters by adopting a density-based clustering method, calculating the mass center coordinates of each tower point cluster on the XY plane, and removing the tower point clusters to obtain a point cloud subset only containing wires; Constructing a minimum spanning tree by taking the barycenter of the pole tower as a node, regarding the tree edge as a transmission line span, classifying the wire point cloud into a corresponding span according to the latest tree edge, and dividing a left wire point set and a right wire point set based on orthogonal projection of the main direction of the span; Selecting seed points from each wire point set, and carrying out neighborhood search and cluster growth according to a set plane distance threshold value and a set vertical height difference threshold value to form a continuous wire point cluster; sorting the wire dot clusters along the main direction of the span, constructing indexes, and fitting to generate a three-dimensional LINESTRING geometric object with a Z value; and step six, smoothing the three-dimensional geometric object by adopting Savitzky-Golay filtering, and finally outputting vector data by using a shape file with a Z value.
  2. 2. The method for extracting three-dimensional vector elements of power transmission line based on laser point cloud as claimed in claim 1, wherein the height threshold hmin in the first step is set in one of the following modes, namely adopting 90% of the split value of the point cloud height distribution as a dynamic threshold or adopting a fixed height threshold of 10-15 m.
  3. 3. The three-dimensional vector element extraction method of the power transmission line based on the laser point cloud, which is disclosed in claim 1, is characterized in that the clustering method based on density in the second step is a DBSCAN algorithm, and the condition of judging the pole tower point cluster is that the number Nk of points in the point cluster is more than or equal to 100-300, and the vertical height range delta Zk of the point cluster is more than or equal to 15-16m.
  4. 4. The three-dimensional vector element extraction method of the power transmission line based on the laser point cloud, which is disclosed in claim 1, is characterized in that a Prim algorithm is adopted in the construction of the minimum spanning tree in the step three, and Euclidean distance between barycenter nodes of a pole tower is used as an edge weight.
  5. 5. The method for extracting the three-dimensional vector elements of the power transmission line based on the laser point cloud, which is disclosed in claim 1, is characterized in that in the fourth step, the plane distance threshold is 10m, the vertical height difference threshold is 0.5m, and the cluster growth adopts a breadth-first expansion mode.
  6. 6. The method for extracting the three-dimensional vector elements of the power transmission line based on the laser point cloud, which is disclosed by claim 1, is characterized in that the sorting mode of the wire point clusters in the fifth step is that the point cloud is projected to an XY plane, and point set indexes are built and sorted along the direction of the corresponding tree edge of the span.
  7. 7. The method for extracting the three-dimensional vector elements of the power transmission line based on the laser point cloud as claimed in claim 1, wherein in the step six, savitzky-Golay filtering is carried out by determining a filtering coefficient by setting window width 2r+1 and polynomial order m, and smoothing the x, y and z sequences of the three-dimensional LINESTRING respectively.
  8. 8. The method for extracting the three-dimensional vector elements of the power transmission line based on the laser point cloud, which is disclosed in claim 1, is characterized in that the original laser point cloud is acquired through an airborne laser radar device, the acquisition device is DJI Matrice 300, 300 RTK, and the acquisition range covers the 100m areas on the two sides of the center line of the power transmission corridor.
  9. 9. The three-dimensional vector element extraction method of the power transmission line based on the laser point cloud is characterized in that the method for dividing left and right wire point sets in the third step is characterized in that projection values S, S >0 of the wire points in the orthogonal direction of the main direction of the span are calculated and are included in the left wire point set, S <0 is included in the right wire point set, and when S < is less than a set minimum value, the wire point sets are marked as neutral points or distributed according to local density.
  10. 10. The method for extracting the three-dimensional vector elements of the power transmission line based on the laser point cloud, which is disclosed in claim 1, is characterized in that the seed points in the fourth step are selected by selecting the point with the smallest sum of squares (x 2+ y 2) of longitude and latitude in the wire point set as the clustering seed point.

Description

Three-dimensional vector element extraction method of power transmission line based on laser point cloud Technical Field The invention belongs to the technical field of three-dimensional vector element extraction of a power transmission line, and particularly relates to a three-dimensional vector element extraction method of the power transmission line based on laser point cloud. The invention belongs to the technical field of three-dimensional vector element extraction of a power transmission line, and particularly relates to a three-dimensional vector element extraction method of the power transmission line based on laser point cloud. Background The current transmission line is used as a core infrastructure for cross-regional energy transmission, often needs to traverse complex terrains such as low hills and high vegetation coverage areas, and partial areas face forest fire risks of high Wen Duofeng in summer and dry in winter, so that the monitoring requirements on the spatial position accuracy and the element integrity of the transmission line are increasingly urgent. The traditional power transmission line element extraction is dependent on manual mapping or two-dimensional image analysis, the manual mapping is low in efficiency and high in cost, is limited by terrain complexity and bad weather, is difficult to realize rapid coverage of a large-scale line, the two-dimensional image cannot effectively reflect the three-dimensional space form of the line, is difficult to meet the accurate acquisition requirements of key parameters such as pole height and wire arc, and brings great constraints to line inspection, hidden danger investigation and risk assessment. The existing extraction technology based on laser point cloud can acquire high-precision three-dimensional data by means of LiDAR equipment, but has obvious limitations in practical application, namely, the original point cloud comprises a large number of ground points, low vegetation points and noise points, misjudgment or missed judgment is easily caused in subsequent tower identification if effective filtering treatment is not carried out, meanwhile, the association topology construction of a tower and a wire lacks an automatic means, span segmentation is dependent on manual annotation, the wire point cloud is often scattered due to distribution and is interfered by peripheral vegetation, accurate distinction and continuous clustering of left and right wires are difficult to realize, in addition, after wire fitting, local jitter is easily caused due to factors such as sensor noise, wind swing and the like, the generated vector data cannot be directly adapted to a GIS system, additional manual processing is required, the automation degree and the result reliability of element extraction are seriously influenced, and the high-efficiency and accurate three-dimensional vector element acquisition requirement of a transmission line under a complex scene is difficult to meet. Disclosure of Invention The invention aims to solve the technical problems and provides a three-dimensional vector element extraction method of a power transmission line based on laser point cloud. In view of the above, the invention provides a three-dimensional vector element extraction method of a power transmission line based on laser point cloud, comprising the following steps of firstly, carrying out high threshold filtering on an original laser point cloud, removing ground points, low vegetation and low Cheng Zaosheng points, and reserving related point clouds of an overhead structure; projecting the filtered point cloud to an XY plane, identifying tower point clusters by adopting a density-based clustering method, calculating the mass center coordinates of each tower point cluster on the XY plane, and removing the tower point clusters to obtain a point cloud subset only containing wires; Constructing a minimum spanning tree by taking the barycenter of the pole tower as a node, regarding the tree edge as a transmission line span, classifying the wire point cloud into a corresponding span according to the latest tree edge, and dividing a left wire point set and a right wire point set based on orthogonal projection of the main direction of the span; Selecting seed points from each wire point set, and carrying out neighborhood search and cluster growth according to a set plane distance threshold value and a set vertical height difference threshold value to form a continuous wire point cluster; sorting the wire dot clusters along the main direction of the span, constructing indexes, and fitting to generate a three-dimensional LINESTRING geometric object with a Z value; and step six, smoothing the three-dimensional geometric object by adopting Savitzky-Golay filtering, and finally outputting vector data by using a shape file with a Z value. Preferably, the height threshold hmin in the first step is set in one of the following modes, namely, the 90% quantile value of the point clo