Point cloud extraction algorithm based on TLS data in railway stations
The geometry information pertaining to railroads within stations holds significant importance for railroad safety management and maintenance.Since there are multiple rail tracks in a station,it is difficult to automatically extract point cloud of tracks from large field point cloud.Terrestrial Laser Scanning(TLS),as a non-contact measurement means,can quickly obtain large amounts of point cloud data in railroad scenes.Based on Delaunay triangle network clustering,a point cloud extraction algorithm was proposed to extract rail track point cloud from the point cloud data of a railroad station obtained by TLS technology.Based on the idea of segmentation-merging,the method segmented the high-precision point cloud data of railway station yards into several sections along the direction of the railway tracks,and then used the triangle mesh clustering algorithm to extract the steel rail top surface point cloud based on the track regularity feature of the railway tracks.In the merging stage,the rail surface point cloud information of each section in the station yard was integrated,and the rail surface point cloud of each section were connected while matching the left and right rail surface point cloud.The method was verified using data from Yulin station,demonstrating an overall accuracy of 93.95%at the object level,the integrity of 90.57%,and an accuracy of 97.59%.Compared with the planar grid method,the overall accuracy of extraction is improved by 5.65%and the accuracy is improved by 18.49%.Based on the extracted width of trail surfaces and gauges at 10 cross sections,statistical results indicate that the standard deviations of the rail surface width and the gauge are 5.2 mm and 5.3 mm respectively,meeting the precision requirement of engineering.The example results show that the algorithm can accurately and effectively extract the point cloud from the top surface of the tracks of multiple railroads within the station,which provides a reference idea for the TLS data extraction work in other structures within railroad scenes.
国家科技期刊平台
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