Ocenjevanje geometrične podobnosti oblakov točk aerolaserskega skeniranja : doktorska disertacija

Urbančič, Tilen (author), Stopar, Bojan (mentor), Kosmatin Fras, Mojca (comentor)

V doktorski nalogi se ukvarjamo z ocenjevanjem geometrične podobnosti oblakov točk, kjer pri registraciji uporabimo umetne tarče. Umetnim tarčam v večini primerov lahko natančno in točno določimo koordinate iz oblaka točk aerolaserskega skeniranja ter s klasično izmero v izbranem koordinatnem sistemu. Glavni namen naloge je raziskati uporabnost umetnih tarč stožčaste oblike v postopkih ocenjevanja kakovosti oblakov točk. Z izvedbo dveh praktičnih testov določimo najboljšo geometrijo stožca za uporabo v postopkih laserskega skeniranja. Uporabnost stožcev kot ALS tarč izboljšamo z vzpostavitvijo postopka samodejnega prepoznavanja točk stožca iz oblaka točk z metodo RANSAC. Fizičnim modelom stožcev za uporabo v postopkih ALS določimo parametre ter adicijske konstante. Na osnovi obdelav oblakov točk dveh testnih aerolaserskih skeniranj analiziramo kakovost odbojev od stožcev ter določimo kriterije za kakovostno uporabo takih tarč. Opišemo in predstavimo rezultate vzpostavljene referenčne geodetske mreže v Radovljici, ki jo uporabimo za ocenjevanje kakovosti oblakov točk aerolaserskega skeniranja oz. njihove geometrične podobnosti. Z različnimi analizami preverjamo natančnost in točnost izdelanih modelov reliefa ter koordinat kontrolnih točk na različnih odbojnih površinah. Uporabnost stožcev, kot umetnih tarč, določimo na osnovi primerjav cenilk kakovosti oblakov točk na kontrolnih točkah različnih odbojnih površin pri registraciji s stožci, črno-belimi tarčami in na osnovi drugih talnih točk.

• Language: Slovenian
• Keywords: grajeno okolje, gradbeništvo, disertacije, aerolasersko skeniranje, umetna tarča, storžec, kakovost, geometrija oblaka točk
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publisher: [T. Urbančič]
• Year: 2017
• PID: 20.500.12556/RUL-99245
• UDC: 004:528.715(043)
• COBISS.SI-ID: 8223329
• Publication date in RUL: 09.01.2018

URBANČIČ, Tilen, 2017, Ocenjevanje geometrične podobnosti oblakov točk aerolaserskega skeniranja : doktorska disertacija [online]. Doctoral dissertation. T. Urbančič. [Accessed 30 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=99245

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.
• Licensing start date: 09.01.2018

Secondary language

• Language: English
• Title: Assessment of Geometric Similarity of Airborne Laser Scanning Point Clouds : doctoral dissertation

Abstract

This doctoral thesis addresses the assessment of the geometric similarity of point clouds, which are registered with the use of artificial targets. We can usually accurately define the coordinates from the point clouds obtained from airborne laser scanning of artificial targets or by a classic measurement within a chosen coordinate system. The main goal of this thesis is to research the use of cone shaped artificial targets in the assessment process of point clouds. By performing two practical tests we have managed to determine the best geometry of the cone for use in laser scanning procedures. The use of cones as ALS targets is improved with the automatic point recognition procedure with the RANSAC method. We need to define the parameters and additional constants for the physical models of the cones used in ALS procedures. From the analysis of the point clouds obtained by two test airborne laser scans we defined the quality of the reflections given by the cones and defined the criteria for the qualitative use of such targets. We described and presented the results of the established referential geodetic network in Radovljica, which we used in order to evaluate the quality of the point clouds obtained from an airborne laser scan, i.e. their geometric similarities. Through various analyses we verified the accuracy and precision of the created models and the coordinates of the control points on the various reflective surfaces. The usefulness of cones as artificial targets is defined by comparing the quality of the point clouds on control points obtained from various reflective surfaces when registered with cones, black and white targets and other ground points.

• Keywords: building environment, civil engineering, thesis, airborne laser scanning, artificial target, cone, quality, point cloud geometry