OPTIMIZATION OF TARGET-BASED TLS MEASUREMENTS

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-03-4 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 23, 295-302 pp, DOI: 10.5593/sgem2017/23/S10.036

ABSTRACT

Terrestrial Laser Scanning (TLS) in LiDAR technology is a commonly used method in obtaining geometric information about objects. Individual scan stations can be combined into one project using the cloud-to-cloud method or based on targets (chessboards or spheres). Target-based registration with spheres is very convenient because in planar view always circle is visible, no matter of the angle of view. On the other hand, it is inconvenient to use the same size of spheres throughout the project. Large spheres are easily identifiable by software over longer distances, but in the interiors of buildings generate large shadows. Therefore, within this work, detection of spheres in different sizes, at different distances and with different scan parameters (resolution and quality) were verified. Five different size of spheres were scanned: 5 cm, 8 cm, 12 cm, 15 cm and original FARO spheres 13.9 cm diameter. Point clouds with different resolution, from 1/1 (full resolution) to 1/32 (the lowest resolution) were processing in FARO Scene 5.0 in searching targets mode.

Keywords: Terrestrial Laser Scanning, point cloud density, target finding, spheres