Power Line Extraction and Obstacle Inspection of Unmanned Aerial Vehicle Oblique Images Constrained by the Vertical Plane

Abstract

AbstractUnmanned aerial vehicle (UAV) inspection of vegetation or other obstacles in power transmission line corridors is an economical and efficient method. Spatial power lines cannot be directly restored in the single airborne photographic geometry, and automatic robust extraction of power lines under complex background is a bottleneck problem in the current transmission line reconstruction. Thus, a robust restoration method of the power line spatial position based on the vertical plane constraint was proposed that can restore the entire power line three‐dimensional (3D) points. First, the spatial position of the hanging points at both ends of the power line was solved based on an insulator plumb, and the vertical plane of the power line was determined. A light beam passing through the photographing centre and the image point could then be determined for any image point on the image power line. The intersection point of the light beam and the vertical plane of the power line was the point of the spatial power line. The proposed method was used to select a few (three or more) power line seed points manually to calculate the corresponding 3D space points and then fit these points to obtain the dense and uniform 3D points of power line. After restoring the spatial power line, the minimum distance error line segment based on splitting was used to approximate the 3D point sequence of the power line, and it was divided into several straight‐line segments. The spatial buffer zone was established with each line segment as the centre and a safety distance as the radius to detect possible obstacles in the power line corridor. Finally, a set of simulated and actual data were used for verification and analysis. Results show that the method can effectively detect obstacles around the power line, and the accuracy is within 0.25 m.