@misc{Werner2024,
  type      = {Master Thesis},
  author    = {Werner, Lennart},
  title     = {Terrain Mapping for Autonomous Navigation of Lunar Rovers},
  doi       = {10.25972/OPUS-35826},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-358268},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Autonomous mobile robots operating in unknown terrain have to guide their drive decisions through local perception. Local mapping and traversability analysis is essential for safe rover operation and low level locomotion. This thesis deals with the challenge of building a local, robot centric map from ultra short baseline stereo imagery for height and traversability estimation. Several grid-based, incremental mapping algorithms are compared and evaluated in a multi size, multi resolution framework. A new, covariance based mapping update is introduced, which is capable of detecting sub- cellsize obstacles and abstracts the terrain of one cell as a first order surface. The presented mapping setup is capable of producing reliable ter- rain and traversability estimates under the conditions expected for the Cooperative Autonomous Distributed Robotic Exploreration (CADRE) mission. Algorithmic- and software architecture design targets high reliability and efficiency for meeting the tight constraints implied by CADRE's small on-board embedded CPU. Extensive evaluations are conducted to find possible edge-case scenar- ios in the operating envelope of the map and to confirm performance parameters. The research in this thesis targets the CADRE mission, but is applicable to any form of mobile robotics which require height- and traversability mapping.},
  subject      = {Mondfahrzeug},
  language  = {en}
}
@phdthesis{Bleier2023,
  author    = {Bleier, Michael},
  title     = {Underwater Laser Scanning - Refractive Calibration, Self-calibration and Mapping for 3D Reconstruction},
  isbn      = {978-3-945459-45-4},
  doi       = {10.25972/OPUS-32269},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322693},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {There is great interest in affordable, precise and reliable metrology underwater: Archaeologists want to document artifacts in situ with high detail. In marine research, biologists require the tools to monitor coral growth and geologists need recordings to model sediment transport. Furthermore, for offshore construction projects, maintenance and inspection millimeter-accurate measurements of defects and offshore structures are essential. While the process of digitizing individual objects and complete sites on land is well understood and standard methods, such as Structure from Motion or terrestrial laser scanning, are regularly applied, precise underwater surveying with high resolution is still a complex and difficult task. Applying optical scanning techniques in water is challenging due to reduced visibility caused by turbidity and light absorption. However, optical underwater scanners provide significant advantages in terms of achievable resolution and accuracy compared to acoustic systems. This thesis proposes an underwater laser scanning system and the algorithms for creating dense and accurate 3D scans in water. It is based on laser triangulation and the main optical components are an underwater camera and a cross-line laser projector. The prototype is configured with a motorized yaw axis for capturing scans from a tripod. Alternatively, it is mounted to a moving platform for mobile mapping. The main focus lies on the refractive calibration of the underwater camera and laser projector, the image processing and 3D reconstruction. For highest accuracy, the refraction at the individual media interfaces must be taken into account. This is addressed by an optimization-based calibration framework using a physical-geometric camera model derived from an analytical formulation of a ray-tracing projection model. In addition to scanning underwater structures, this work presents the 3D acquisition of semi-submerged structures and the correction of refraction effects. As in-situ calibration in water is complex and time-consuming, the challenge of transferring an in-air scanner calibration to water without re-calibration is investigated, as well as self-calibration techniques for structured light. The system was successfully deployed in various configurations for both static scanning and mobile mapping. An evaluation of the calibration and 3D reconstruction using reference objects and a comparison of free-form surfaces in clear water demonstrate the high accuracy potential in the range of one millimeter to less than one centimeter, depending on the measurement distance. Mobile underwater mapping and motion compensation based on visual-inertial odometry is demonstrated using a new optical underwater scanner based on fringe projection. Continuous registration of individual scans allows the acquisition of 3D models from an underwater vehicle. RGB images captured in parallel are used to create 3D point clouds of underwater scenes in full color. 3D maps are useful to the operator during the remote control of underwater vehicles and provide the building blocks to enable offshore inspection and surveying tasks. The advancing automation of the measurement technology will allow non-experts to use it, significantly reduce acquisition time and increase accuracy, making underwater metrology more cost-effective.},
  subject      = {Selbstkalibrierung},
  language  = {en}
}
@phdthesis{Wagner2023,
  author    = {Wagner, Jan Cetric},
  title     = {Maximalnetzplan zur reaktiven Steuerung von Produktionsabl{\"a}ufen},
  isbn      = {978-3-945459-43-0},
  doi       = {10.25972/OPUS-30545},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-305452},
  school      = {Universit{\"a}t W{\"u}rzburg},
  pages     = {182},
  year      = {2023},
  abstract  = {In produzierenden Unternehmen werden verschiedene Vorgehensweisen zur Planung, {\"U}berwachung und Steuerung von Produktionsabl{\"a}ufen eingesetzt. Einer dieser Methoden wird als Vorgangsknotennetzplantechnik bezeichnet. Die einzelnen Produktionsschritte werden als Knoten definiert und durch Pfeile miteinander verbunden. Die Pfeile stellen die Beziehungen der jeweiligen Vorg{\"a}nge zueinander und damit den Produktionsablauf dar. Diese Technik erlaubt den Anwendern einen umfassenden {\"U}berblick {\"u}ber die einzelnen Prozessrelationen. Zus{\"a}tzlich k{\"o}nnen mit ihr Vorgangszeiten und Produktfertigstellungszeiten ermittelt werden, wodurch eine ausf{\"u}hrliche Planung der Produktion erm{\"o}glicht wird. Ein Nachteil dieser Technik begr{\"u}ndet sich in der alleinigen Darstellung einer ausf{\"u}hrbaren Prozessabfolge. Im Falle eines St{\"o}rungseintritts mit der Folge eines nicht durchf{\"u}hrbaren Vorgangs muss von dem origin{\"a}ren Prozess abgewichen werden. Aufgrund dessen wird eine Neuplanung erforderlich. Es werden Alternativen f{\"u}r den gest{\"o}rten Vorgang ben{\"o}tigt, um eine Fortf{\"u}hrung des Prozesses ungeachtet der St{\"o}rung zu erreichen. Innerhalb dieser Arbeit wird daher eine Erweiterung der Vorgangsknotennetzplantechnik beschrieben, die es erlaubt, erg{\"a}nzend zu dem geplanten Soll-Prozess Alternativvorg{\"a}nge f{\"u}r einzelne Vorg{\"a}nge darzulegen. Diese Methode wird als Maximalnetzplan bezeichnet. Die Alternativen werden im Falle eines St{\"o}rungseintritts automatisch evaluiert und dem Anwender in priorisierter Reihenfolge pr{\"a}sentiert. Durch die Verwendung des Maximalnetzplans kann eine aufwendige Neuplanung vermieden werden. Als Anwendungsbeispiel dient ein Montageprozess, mithilfe dessen die Verwendbarkeit der Methode dargelegt wird. Weiterf{\"u}hrend zeigt eine zeitliche Analyse zufallsbedingter Maximalnetzpl{\"a}ne eine Begr{\"u}ndung zur Durchf{\"u}hrung von Alternativen und damit den Nutzen des Maximalnetzplans auf. Zus{\"a}tzlich sei angemerkt, dass innerhalb dieser Arbeit verwendete Begrifflichkeiten wie Anwender, Werker oder Mitarbeiter in maskuliner Schreibweise niedergeschrieben werden. Dieses ist ausschließlich der Einfachheit geschuldet und nicht dem Zweck der Diskriminierung anderer Geschlechter dienlich. Die verwendete Schreibweise soll alle Geschlechter ansprechen, ob m{\"a}nnlich, weiblich oder divers.},
  subject      = {Produktionsplanung},
  language  = {de}
}
@phdthesis{Scharnagl2022,
  author    = {Scharnagl, Julian},
  title     = {Distributed Guidance, Navigation and Control for Satellite Formation Flying Missions},
  isbn      = {978-3-945459-42-3},
  doi       = {10.25972/OPUS-28753},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287530},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {Ongoing changes in spaceflight - continuing miniaturization, declining costs of rocket launches and satellite components, and improved satellite computing and control capabilities - are advancing Satellite Formation Flying (SFF) as a research and application area. SFF enables new applications that cannot be realized (or cannot be realized at a reasonable cost) with conventional single-satellite missions. In particular, distributed Earth observation applications such as photogrammetry and tomography or distributed space telescopes require precisely placed and controlled satellites in orbit. Several enabling technologies are required for SFF, such as inter-satellite communication, precise attitude control, and in-orbit maneuverability. However, one of the most important requirements is a reliable distributed Guidance, Navigation and Control (GNC) strategy. This work addresses the issue of distributed GNC for SFF in 3D with a focus on Continuous Low-Thrust (CLT) propulsion satellites (e.g., with electric thrusters) and concentrates on circular low Earth orbits. However, the focus of this work is not only on control theory, but control is considered as part of the system engineering process of typical small satellite missions. Thus, common sensor and actuator systems are analyzed to derive their characteristics and their impacts on formation control. This serves as the basis for the design, implementation, and evaluation of the following control approaches: First, a Model Predictive Control (MPC) method with specific adaptations to SFF and its requirements and constraints; second, a distributed robust controller that combines consensus methods for distributed system control and \$H_{\infty}\$ robust control; and finally, a controller that uses plant inversion for control and combines it with a reference governor to steer the controller to the target on an optimal trajectory considering several constraints. The developed controllers are validated and compared based on extensive software simulations. Realistic 3D formation flight scenarios were taken from the Networked Pico-Satellite Distributed System Control (NetSat) cubesat formation flight mission. The three compared methods show different advantages and disadvantages in the different application scenarios. The distributed robust consensus-based controller for example lacks the ability to limit the maximum thrust, so it is not suitable for satellites with CLT. But both the MPC-based approach and the plant inversionbased controller are suitable for CLT SFF applications, while showing again distinct advantages and disadvantages in different scenarios. The scientific contribution of this work may be summarized as the creation of novel and specific control approaches for the class of CLT SFF applications, which is still lacking methods withstanding the application in real space missions, as well as the scientific evaluation and comparison of the developed methods.},
  subject      = {Kleinsatellit},
  language  = {en}
}
@phdthesis{Freimann2022,
  author    = {Freimann, Andreas},
  title     = {Efficient Communication in Networks of Small Low Earth Orbit Satellites and Ground Stations},
  isbn      = {978-3-945459-41-6},
  doi       = {10.25972/OPUS-28052},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-280521},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {With the miniaturization of satellites a fundamental change took place in the space industry. Instead of single big monolithic satellites nowadays more and more systems are envisaged consisting of a number of small satellites to form cooperating systems in space. The lower costs for development and launch as well as the spatial distribution of these systems enable the implementation of new scientific missions and commercial services. With this paradigm shift new challenges constantly emerge for satellite developers, particularly in the area of wireless communication systems and network protocols. Satellites in low Earth orbits and ground stations form dynamic space-terrestrial networks. The characteristics of these networks differ fundamentally from those of other networks. The resulting challenges with regard to communication system design, system analysis, packet forwarding, routing and medium access control as well as challenges concerning the reliability and efficiency of wireless communication links are addressed in this thesis. The physical modeling of space-terrestrial networks is addressed by analyzing existing satellite systems and communication devices, by evaluating measurements and by implementing a simulator for space-terrestrial networks. The resulting system and channel models were used as a basis for the prediction of the dynamic network topologies, link properties and channel interference. These predictions allowed for the implementation of efficient routing and medium access control schemes for space-terrestrial networks. Further, the implementation and utilization of software-defined ground stations is addressed, and a data upload scheme for the operation of small satellite formations is presented.},
  subject      = {Satellitenfunk},
  language  = {en}
}
@phdthesis{Leutert2021,
  author    = {Leutert, Florian},
  title     = {Flexible Augmented Reality Systeme f{\"u}r robotergest{\"u}tzte Produktionsumgebungen},
  isbn      = {978-3-945459-39-3},
  doi       = {10.25972/OPUS-24972},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249728},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Produktionssysteme mit Industrierobotern werden zunehmend komplex; waren deren Arbeitsbereiche fr{\"u}her noch statisch und abgeschirmt, und die programmierten Abl{\"a}ufe gleichbleibend, so sind die Anforderungen an moderne Robotik-Produktionsanlagen gestiegen: Diese sollen sich jetzt mithilfe von intelligenter Sensorik auch in unstrukturierten Umgebungen einsetzen lassen, sich bei sinkenden Losgr{\"o}ßen aufgrund individualisierter Produkte und h{\"a}ufig {\"a}ndernden Produktionsaufgaben leicht rekonfigurieren lassen, und sogar eine direkte Zusammenarbeit zwischen Mensch und Roboter erm{\"o}glichen. Gerade auch bei dieser Mensch-Roboter-Kollaboration wird es damit notwendig, dass der Mensch die Daten und Aktionen des Roboters leicht verstehen kann. Aufgrund der gestiegenen Anforderungen m{\"u}ssen somit auch die Bedienerschnittstellen dieser Systeme verbessert werden. Als Grundlage f{\"u}r diese neuen Benutzerschnittstellen bietet sich Augmented Reality (AR) als eine Technologie an, mit der sich komplexe r{\"a}umliche Daten f{\"u}r den Bediener leicht verst{\"a}ndlich darstellen lassen. Komplexe Informationen werden dabei in der Arbeitsumgebung der Nutzer visualisiert und als virtuelle Einblendungen sichtbar gemacht, und so auf einen Blick verst{\"a}ndlich. Die diversen existierenden AR-Anzeigetechniken sind f{\"u}r verschiedene Anwendungsfelder unterschiedlich gut geeignet, und sollten daher flexibel kombinier- und einsetzbar sein. Auch sollen diese AR-Systeme schnell und einfach auf verschiedenartiger Hardware in den unterschiedlichen Arbeitsumgebungen in Betrieb genommen werden k{\"o}nnen. In dieser Arbeit wird ein Framework f{\"u}r Augmented Reality Systeme vorgestellt, mit dem sich die genannten Anforderungen umsetzen lassen, ohne dass daf{\"u}r spezialisierte AR-Hardware notwendig wird. Das Flexible AR-Framework kombiniert und b{\"u}ndelt daf{\"u}r verschiedene Softwarefunktionen f{\"u}r die grundlegenden AR-Anzeigeberechnungen, f{\"u}r die Kalibrierung der notwendigen Hardware, Algorithmen zur Umgebungserfassung mittels Structured Light sowie generische ARVisualisierungen und erlaubt es dadurch, verschiedene AR-Anzeigesysteme schnell und flexibel in Betrieb zu nehmen und parallel zu betreiben. Im ersten Teil der Arbeit werden Standard-Hardware f{\"u}r verschiedene AR-Visualisierungsformen sowie die notwendigen Algorithmen vorgestellt, um diese flexibel zu einem AR-System zu kombinieren. Dabei m{\"u}ssen die einzelnen verwendeten Ger{\"a}te pr{\"a}zise kalibriert werden; hierf{\"u}r werden verschiedene M{\"o}glichkeiten vorgestellt, und die mit ihnen dann erreichbaren typischen Anzeige- Genauigkeiten in einer Evaluation charakterisiert. Nach der Vorstellung der grundlegenden ARSysteme des Flexiblen AR-Frameworks wird dann eine Reihe von Anwendungen vorgestellt, bei denen das entwickelte System in konkreten Praxis-Realisierungen als AR-Benutzerschnittstelle zum Einsatz kam, unter anderem zur {\"U}berwachung von, Zusammenarbeit mit und einfachen Programmierung von Industrierobotern, aber auch zur Visualisierung von komplexen Sensordaten oder zur Fernwartung. Im Verlauf der Arbeit werden dadurch die Vorteile, die sich durch Verwendung der AR-Technologie in komplexen Produktionssystemen ergeben, herausgearbeitet und in Nutzerstudien belegt.},
  subject      = {Erweiterte Realit{\"a}t <Informatik>},
  language  = {de}
}
@phdthesis{Dombrovski2022,
  author    = {Dombrovski, Veaceslav},
  title     = {Software Framework to Support Operations of Nanosatellite Formations},
  isbn      = {978-3-945459-38-6},
  doi       = {10.25972/OPUS-24931},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249314},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {Since the first CubeSat launch in 2003, the hardware and software complexity of the nanosatellites was continuosly increasing. To keep up with the continuously increasing mission complexity and to retain the primary advantages of a CubeSat mission, a new approach for the overall space and ground software architecture and protocol configuration is elaborated in this work. The aim of this thesis is to propose a uniform software and protocol architecture as a basis for software development, test, simulation and operation of multiple pico-/nanosatellites based on ultra-low power components. In contrast to single-CubeSat missions, current and upcoming nanosatellite formation missions require faster and more straightforward development, pre-flight testing and calibration procedures as well as simultaneous operation of multiple satellites. A dynamic and decentral Compass mission network was established in multiple active CubeSat missions, consisting of uniformly accessible nodes. Compass middleware was elaborated to unify the communication and functional interfaces between all involved mission-related software and hardware components. All systems can access each other via dynamic routes to perform service-based M2M communication. With the proposed model-based communication approach, all states, abilities and functionalities of a system are accessed in a uniform way. The Tiny scripting language was designed to allow dynamic code execution on ultra-low power components as a basis for constraint-based in-orbit scheduler and experiment execution. The implemented Compass Operations front-end enables far-reaching monitoring and control capabilities of all ground and space systems. Its integrated constraint-based operations task scheduler allows the recording of complex satellite operations, which are conducted automatically during the overpasses. The outcome of this thesis became an enabling technology for UWE-3, UWE-4 and NetSat CubeSat missions.},
  subject      = {Kleinsatellit},
  language  = {en}
}
@phdthesis{Kramer2021,
  author    = {Kramer, Alexander},
  title     = {Orbit control of a very small satellite using electric propulsion},
  isbn      = {978-3-945459-34-8 (online)},
  doi       = {10.25972/OPUS-24155},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241552},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Miniaturized satellites on a nanosatellite scale below 10kg of total mass contribute most to the number of launched satellites into Low Earth Orbit today. This results from the potential to design, integrate and launch these space missions within months at very low costs. In the past decade, the reliability in the fields of system design, communication, and attitude control have matured to allow for competitive applications in Earth observation, communication services, and science missions. The capability of orbit control is an important next step in this development, enabling operators to adjust orbits according to current mission needs and small satellite formation flight, which promotes new measurements in various fields of space science. Moreover, this ability makes missions with altitudes above the ISS comply with planned regulations regarding collision avoidance maneuvering. This dissertation presents the successful implementation of orbit control capabilities on the pico-satellite class for the first time. This pioneering achievement is demonstrated on the 1U CubeSat UWE-4. A focus is on the integration and operation of an electric propulsion system on miniaturized satellites. Besides limitations in size, mass, and power of a pico-satellite, the choice of a suitable electric propulsion system was driven by electromagnetic cleanliness and the use as a combined attitude and orbit control system. Moreover, the integration of the propulsion system leaves the valuable space at the outer faces of the CubeSat structure unoccupied for future use by payloads. The used NanoFEEP propulsion system consists of four thruster heads, two neutralizers and two Power Processing Units (PPUs). The thrusters can be used continuously for 50 minutes per orbit after the liquefaction of the propellant by dedicated heaters. The power consumption of a PPU with one activated thruster, its heater and a neutralizer at emitter current levels of 30-60μA or thrust levels of 2.6-5.5μN, respectively, is in the range of 430-1050mW. Two thruster heads were activated within the scope of in-orbit experiments. The thrust direction was determined using a novel algorithm within 15.7° and 13.2° of the mounting direction. Despite limited controllability of the remaining thrusters, thrust vector pointing was achieved using the magnetic actuators of the Attitude and Orbit Control System. In mid 2020, several orbit control maneuvers changed the altitude of UWE-4, a first for pico-satellites. During the orbit lowering scenario with a duration of ten days, a single thruster head was activated in 78 orbits for 5:40 minutes per orbit. This resulted in a reduction of the orbit altitude by about 98.3m and applied a Delta v of 5.4cm/s to UWE-4. The same thruster was activated in another experiment during 44 orbits within five days for an average duration of 7:00 minutes per orbit. The altitude of UWE-4 was increased by about 81.2m and a Delta v of 4.4cm/s was applied. Additionally, a collision avoidance maneuver was executed in July 2020, which increased the distance of closest approach to the object by more than 5000m.},
  subject      = {Kleinsatellit},
  language  = {en}
}
@techreport{RossiMaurelliUnnithanetal.2021,
  author    = {Rossi, Angelo Pio and Maurelli, Francesco and Unnithan, Vikram and Dreger, Hendrik and Mathewos, Kedus and Pradhan, Nayan and Corbeanu, Dan-Andrei and Pozzobon, Riccardo and Massironi, Matteo and Ferrari, Sabrina and Pernechele, Claudia and Paoletti, Lorenzo and Simioni, Emanuele and Maurizio, Pajola and Santagata, Tommaso and Borrmann, Dorit and N{\"u}chter, Andreas and Bredenbeck, Anton and Zevering, Jasper and Arzberger, Fabian and Reyes Mantilla, Camilo Andr{\´e}s},
  title     = {DAEDALUS - Descent And Exploration in Deep Autonomy of Lava Underground Structures},
  isbn      = {978-3-945459-33-1},
  issn      = {1868-7466},
  doi       = {10.25972/OPUS-22791},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227911},
  pages     = {188},
  year      = {2021},
  abstract  = {The DAEDALUS mission concept aims at exploring and characterising the entrance and initial part of Lunar lava tubes within a compact, tightly integrated spherical robotic device, with a complementary payload set and autonomous capabilities. The mission concept addresses specifically the identification and characterisation of potential resources for future ESA exploration, the local environment of the subsurface and its geologic and compositional structure. A sphere is ideally suited to protect sensors and scientific equipment in rough, uneven environments. It will house laser scanners, cameras and ancillary payloads. The sphere will be lowered into the skylight and will explore the entrance shaft, associated caverns and conduits. Lidar (light detection and ranging) systems produce 3D models with high spatial accuracy independent of lighting conditions and visible features. Hence this will be the primary exploration toolset within the sphere. The additional payload that can be accommodated in the robotic sphere consists of camera systems with panoramic lenses and scanners such as multi-wavelength or single-photon scanners. A moving mass will trigger movements. The tether for lowering the sphere will be used for data communication and powering the equipment during the descending phase. Furthermore, the connector tether-sphere will host a WIFI access point, such that data of the conduit can be transferred to the surface relay station. During the exploration phase, the robot will be disconnected from the cable, and will use wireless communication. Emergency autonomy software will ensure that in case of loss of communication, the robot will continue the nominal mission.},
  subject      = {Mond},
  language  = {en}
}
@phdthesis{SchauerMarinRodrigues2020,
  author    = {Schauer Marin Rodrigues, Johannes},
  title     = {Detecting Changes and Finding Collisions in 3D Point Clouds : Data Structures and Algorithms for Post-Processing Large Datasets},
  isbn      = {978-3-945459-32-4},
  doi       = {10.25972/OPUS-21428},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214285},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {Affordable prices for 3D laser range finders and mature software solutions for registering multiple point clouds in a common coordinate system paved the way for new areas of application for 3D point clouds. Nowadays we see 3D laser scanners being used not only by digital surveying experts but also by law enforcement officials, construction workers or archaeologists. Whether the purpose is digitizing factory production lines, preserving historic sites as digital heritage or recording environments for gaming or virtual reality applications -- it is hard to imagine a scenario in which the final point cloud must also contain the points of "moving" objects like factory workers, pedestrians, cars or flocks of birds. For most post-processing tasks, moving objects are undesirable not least because moving objects will appear in scans multiple times or are distorted due to their motion relative to the scanner rotation. The main contributions of this work are two postprocessing steps for already registered 3D point clouds. The first method is a new change detection approach based on a voxel grid which allows partitioning the input points into static and dynamic points using explicit change detection and subsequently remove the latter for a "cleaned" point cloud. The second method uses this cleaned point cloud as input for detecting collisions between points of the environment point cloud and a point cloud of a model that is moved through the scene. Our approach on explicit change detection is compared to the state of the art using multiple datasets including the popular KITTI dataset. We show how our solution achieves similar or better F1-scores than an existing solution while at the same time being faster. To detect collisions we do not produce a mesh but approximate the raw point cloud data by spheres or cylindrical volumes. We show how our data structures allow efficient nearest neighbor queries that make our CPU-only approach comparable to a massively-parallel algorithm running on a GPU. The utilized algorithms and data structures are discussed in detail. All our software is freely available for download under the terms of the GNU General Public license. Most of the datasets used in this thesis are freely available as well. We provide shell scripts that allow one to directly reproduce the quantitative results shown in this thesis for easy verification of our findings.},
  subject      = {Punktwolke},
  language  = {en}
}