Dresden, Universität, Thesis (doctoral), 1999.

In order to prevent accidents we need to understand them, this is achieved through effective accident investigation. Accident investigation is a complex process of gathering and evaluating information to determine factors that may have implications on the final event. One of the fundamental aspects in the investigation process is to capture geospatial data of the incident, to document the scene in its current condition, providing the investigation team with a record for future reference. The production of plans have conventionally remained the same, with a surveyor tasked to illustrate a 3D scene with 2D representations. Recent developments in instrumentation have provided the geospatial industry with the means to capture vast amounts of 3D data directly using laser scanning. In addition, there have been considerable advancements in software applications which can be used to process the surveyed datasets. This research evaluates the use of the latest technology in respect of accident investigation applying the methodology to fire related incidents, industrial accidents and mining incidents. This is achieved by using a number of case studies that have been undertaken throughout the timeline of the project and whilst working with industry professionals in the field.

Effective planning and management of transportation infrastructure requires adequate geospatial data. Existing geospatial data acquisition techniques based on conventional route surveys are very time consuming, labor intensive, and costly. Mobile laser scanning (MLS) technology enables a rapid collection of enormous volumes of highly dense, irregularly distributed, accurate geo-referenced point cloud data in the format of three-dimensional (3D) point clouds. Today, more and more commercial MLS systems are available for transportation applications. However, many transportation engineers have neither interest in the 3D point cloud data nor know how to transform such data into their computer-aided model (CAD) formatted geometric road information. Therefore, automated methods and software tools for rapid and accurate extraction of 2D/3D road information from the MLS data are urgently needed. This doctoral dissertation deals with the development and implementation aspects of a novel strategy for the automated extraction of road information from the MLS data. The main features of this strategy include: (1) the extraction of road surfaces from large volumes of MLS point clouds, (2) the generation of 2D geo-referenced feature (GRF) images from the road-surface data, (3) the exploration of point density and intensity of MLS data for road-marking extraction, and (4) the extension of tensor voting (TV) for curvilinear pavement crack extraction. In accordance with this strategy, a RoadModeler prototype with three computerized algorithms was developed. They are: (1) road-surface extraction, (2) road-marking extraction, and (3) pavement-crack extraction. Four main contributions of this development can be summarized as follows. Firstly, a curb-based approach to road surface extraction with assistance of the vehicle???s trajectory is proposed and implemented. The vehicle???s trajectory and the function of curbs that separate road surfaces from sidewalks are used to efficiently separate road-surface points from large volume of MLS data. The accuracy of extracted road surfaces is validated with manually selected reference points. Secondly, the extracted road enables accurate detection of road markings and cracks for transportation-related applications in road traffic safety. To further improve computational efficiency, the extracted 3D road data are converted into 2D image data, termed as a GRF image. The GRF image of the extracted road enables an automated road-marking extraction algorithm and an automated crack detection algorithm, respectively. Thirdly, the automated road-marking extraction algorithm applies a point-density-dependent, multi-thresholding segmentation to the GRF image to overcome unevenly distributed intensity caused by the scanning range, the incidence angle, and the surface characteristics of an illuminated object. The morphological operation is then implemented to deal with the presence of noise and incompleteness of the extracted road markings. Fourthly, the automated crack extraction algorithm applies an iterative tensor voting (ITV) algorithm to the GRF image for crack enhancement. The tensor voting, a perceptual organization method that is capable of extracting curvilinear structures from the noisy and corrupted background, is explored and extended into the field of crack detection. The successful development of three algorithms suggests that the RoadModeler strategy offers a solution to the automated extraction of road information from the MLS data. Recommendations are given for future research and development to be conducted to ensure that this progress goes beyond the prototype stage and towards everyday use.

This research addresses the problem of efficiently and robustly reconstructing semantically-rich 3D architectural models from laser-scanned point-clouds. It first covers the pre-existing literature and industrial developments in active-sensing, 3D reconstruction of the built-environment and procedural modelling. It then documents a number of novel contributions to the classical problems of change-detection between temporally varying multi-modal geometric representations and automatic 3D asset creation from airborne and ground point-clouds of buildings. Finally this thesis outlines on-going research and avenues for continued investigation - most notably fully automatic temporal update and revision management for city-scale CAD models via data-driven procedural modelling from point-clouds. In short this thesis documents the outcomes of a research project whose primary aim was to engineer fast, accurate and sparse building reconstruction algorithms. Formally: this thesis puts forward the hypothesis (and advocates) that architectural reconstruction from actively-sensed point-clouds can be addressed more efficiently and affording greater control (over the geometric results) - via deterministic procedurally-driven analysis and optimisation than via stochastic sampling.

Laser scanning cytometry (LSC) is a slide-based method that is used clinically for Quantitative Imaging Cytometry (QIC). A “Clatch” slide, named after the inventor, which is used in conjunction with the LSC for immunophenotyping patient cell samples, has several drawbacks. The slide requires time consuming and laborious pipette steps, making the slide prone to handling errors. The Clatch slide also uses a significant amount of cell sample, limiting the number of analyses for fine needle aspirate (FNA) samples. This thesis details an automated microfluidic system, composed of an embedded circuit, a plastic and polymer microfluidic device, and an aluminum frame, which can perform the same immunophenotyping procedures. This new system reduces the labor from 36 pipette steps to 8, it reduces the amount of cell sample from 180 μL to 56 μL, and it shortens the entire procedure from 75 minutes to 42 minutes.

Laser scanning cytometry (LSC) is a slide-based method that is used clinically for Quantitative Imaging Cytometry (QIC). A “Clatch” slide, named after the inventor, which is used in conjunction with the LSC for immunophenotyping patient cell samples, has several drawbacks. The slide requires time consuming and laborious pipette steps, making the slide prone to handling errors. The Clatch slide also uses a significant amount of cell sample, limiting the number of analyses for fine needle aspirate (FNA) samples. This thesis details an automated microfluidic system, composed of an embedded circuit, a plastic and polymer microfluidic device, and an aluminum frame, which can perform the same immunophenotyping procedures. This new system reduces the labor from 36 pipette steps to 8, it reduces the amount of cell sample from 180 μL to 56 μL, and it shortens the entire procedure from 75 minutes to 42 minutes.

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<p>Den nya mätningstekniken på marknaden kallas terrester laserskanning. Tekniken bygger på att ett instrument, monterat på ett stativ, sänder ut en laserstråle vilken avlänkas i vertikalled av en spegel samtidigt som det roterar. Laserstrålen reflekteras mot de objekt som befinner sig inom laserskannerns synfält och resulterar i ett punktmoln. Punktmolnet innehåller ofta flera miljoner punkter vilka alla erhåller xyz-koordinater. Tekniken har visat sig lämplig vid dokumentation av byggnader och vid modellering samt kartläggning av industrier och tunnelbyggen.</p><p>Denna studie har genomförts på Sweco VBB i Karlstad i syfte att ta reda på hur lämplig terrester laserskanning är vid vardaglig inmätning och kartering av objekt i stadsmiljö. Metoden har jämförts med traditionell inmätning med totalstation utifrån ett antal frågeställningar. I studien laserskannades två korsningar i Vasastaden, Stockholm. Instrumentet som användes var en IMAGER 5006 av märket Zoller+Fröhlich. De totalt sex stycken skanningarna resulterade i punktmoln vilka georefererades genom att måltavlor mättes in med totalstation. Efterbearbetningen bestod av registrering, redigering och reducering av punktmolnen. Genom manuell tolkning av punktmolnen och med hjälp av verktyget Virtual Surveyor i Leica Geosystems programvara Cyclone, kunde olika objekt mätas in och kartläggning av de båda korsningarna ske.</p><p>En generell jämförelse mellan terrester laserskanning och totalstation visar att laserskanning är en snabb metod som ger stora mängder data med hög detaljrikedom, medger en större säkerhet i fält och ger enorma möjligheter för visualisering, modellering och skapande av terrängmodeller. Laserskanning är dock en dyr metod som ger en något sämre noggrannhet och som ännu inte klarar att mäta sträckor över hundra meter. Metoden kräver också totalstation (eller GPS) för georeferering. Studien har också visat att tidsvinsten som uppkommer i fält förloras genom tidsödande efterbearbetning och manuell tolkning av punktmolnet. Trots detta använder idag ett flertal företag denna metod vid inmätning. Slutsatserna pekar främst på att laserskanning som inmätningsmetod lämpar sig bäst över små områden där antalet objekt är högt och där säkerheten i fält är viktig. Dock ses metoden mer som ett komplement till totalstationen genom de möjligheter som erbjuds via visualisering och modellering och därmed inte en ersättare för den senare.</p> / <p>A new technique for surveying is the terrestrial laser scanning. The technique is based on an instrument, mounted on a tripod, emitting a laser pulse which is vertically deflected by a mirror while rotating. The laser pulse is reflected by the objects within the field of view of the laser scanner. The laser scan results in a point cloud most often containing several millions of points which all have XYZ-coordinates. The technique has proven its benefits when documenting buildings, modelling and surveying of industries and tunnels.</p><p>This study has been carried out at Sweco VBB in Karlstad in purpose of finding out how suitable terrestrial laser scanning is for everyday surveying in urban environment. The method has been compared with traditional surveying with total station from a number of questions. In the study two crossings in Vasastaden, Stockholm, were scanned. The instrument used was an IMAGER 5006 from Zoller+Fröhlich. The 6 scannings resulted in point clouds which were georeferenced by using targets and a total station. The post processing consisted of registering, editing and reducing the point clouds. Through manual interpretation of the point clouds and by using the tool Virtual Surveyor in the program Cyclone by Leica Geosystems it was possible to survey different objects at the crossings.</p><p>A general comparison between terrestrial laser scanning and total station shows that laser scanning is a rapid method producing large amounts of data with a high level of details, allows higher security in field and gives enormous possibilities for visualisation, modelling and creating of terrain models. However, laser scanning is an expensive method which gives a slightly lower accuracy and yet cannot be used for longer distances. The method also demands total station (or GPS) for georeferencing. The study has also shown that the saving of time in field is lost by time consuming post processing and manual interpretation of the point cloud. Nonetheless this method is used by several companies for everyday surveying. The conclusions advert mostly that laser scanning is best suitable for small areas where the number of objects is high and where security in field is important. Nevertheless, the method should be seen more as a compliment to the total station because of the possibilities offered by visualisation and modelling and therefore not as a replacement for the latter.</p>

Das Ziel der vorliegenden Arbeit ist es, den Einsatz der konfokalen Laser-Scanning-Mikroskopie (LSM) für die Beurteilung von humanen Osteoblasten auf experimentellen Implantatoberflächen zu prüfen. Die acht Probekörper besaßen anodische Konversionsoberflächen, die aus den Elektrolyten Zirkoniumsulfat, Phosphorsäure und Kaliumfluorid sowie deren Kombinationen hergestellt waren. Als Positivstandard dienten TICER® und Cercon®, als Negativstandard commercial pure Titan (CPT/Reintitan). Diese Probekörper wurden in Chamber Slides mit einer humanen Osteoblastenkultur inkubiert. Am 3., 5., 7. und 10. Versuchstag erfolgte die immunhistochemische Darstellung von Bone-Sialoprotein (BSP). Anschließend wurden im LSM fluoreszenzmikroskopisch 3D-Bildstapel aufgenommen und mit dem 2D-mikroskopischen Verfahren verglichen. Es zeigte sich, dass das Bone-Sialoprotein einen Hinweis auf aktive Osteoblasten darstellt. Die BSP-exprimierenden Strukturen, die sich zu Volumina zusammenfügen, variieren an den verschiedenen Versuchstagen und bei den unterschiedlichen Oberflächenstrukturen. Eine deutlich erhöhte BSP-Expressionsrate wurde bei den elektrolytisch beschichteten Probekörpern aus Zirkoniumsulfat, Kaliumfluorid und Phosphorsäure erfasst. Ein eindeutiger Unterschied zwischen der 2D-Mikroskopie und der LSM ergab sich jedoch nicht. Die LSM erlaubt aber zusätzlich Aussagen über absorbierte Proteine an den Probekörperoberflächen durch eine um 90°-gedrehte Projektion der 3D-Bildstapel.