Automatic extraction of power lines from data of terrestrial and airborne laser scanning

In graduation thesis the main features and theoretical frameworks of terrestrial and airborne laser scanning are presented. The algorithm for Hough transform that is described in detail, was used for searching power lines in a point cloud and on a raster that is generalized from the laser scanning data. The whole procedure of extraction of power lines is described from the pre-processing of data to the final results. Our own program was used for automatic extraction of power lines from pre-treated point cloud. Automatic extraction of power lines was tested from the raster with another program of our own. Both programs that are mentioned above were written in Matlab programming language. In order to increase the effectiveness of both programs, the redundant points that do not represent power lines were eliminated by LAStools. Effectiveness of the methods was estimated in two ways. First it was estimated visually and then by comparing the calculated coordinates of identical intersections of power lines. Estimation was made for all four examples (automatic extraction of power lines and calculation of coordinates of intersections of power lines in the point cloud of terrestrial laser scanning and airborne laser scanning; automatic extraction of power lines and calculation of coordinates of intersections of power lines on raster that is generalized from the terrestrial and airborne laser scanning data). The effect of pre-treated data on processing speed of the program that automatically extracts power lines was evaluated. At the end there are ideas for possible improvements of the methodology and guidelines for further development.