EXTRACTION OF POWER LINES FROM AIRBORNE AND TERRESTRIAL LASER SCANNING DATA USING THE HOUGH TRANSFORM

In this article, a method for the automatic detection of power lines in a horizontal xy plane from airborne and terrestrial laser scanning data is presented. The workflow is composed of four main steps: pre-processing with classification of a point cloud, filtering of the point cloud, the detection of points on the power lines by applying the Hough transform (HT), and vectorisation of power line locations and their intersections. In the pre-processing step, most of the points that are not representing power lines are eliminated via classification of the point cloud. We present our filter, which reduces the number of points in the point cloud further and thus accelerates data processing and increases the reliability of processing in the next steps. We detect the points on the power lines with the HT on the vector points in the xy plane. The final track of the power lines is derived from the straight segments computed by the method of the least squares from the points that HT recognised on the power lines. The results are assessed visually and via relative comparison of the computed intersections coordinates with the reference data manually extracted from the filtered point cloud. The proposed method detects almost all power lines in the test area for both data sets.