Terrestrische Laserscanner finden seit einigen Jahren immer stärkere Anwendung in der Praxis und ersetzen bzw. ergänzen bisherige Messverfahren, oder es werden neue Anwendungsgebiete erschlossen. Werden die Daten eines terrestrischen Laserscanners mit photogrammetrischen Bilddaten kombiniert, ergeben sich viel versprechende Möglichkeiten, weil die Eigenschaften beider Datentypen als weitestgehend komplementär angesehen werden können: Terrestrische Laserscanner erzeugen schnell und zuverlässig dreidimensionale Repräsentationen von Objektoberflächen von einem einzigen Aufnahmestandpunkt aus, während sich zweidimensionale photogrammetrische Bilddaten durch eine sehr gute visuelle Qualität mit hohem Interpretationsgehalt und hoher lateraler Genauigkeit auszeichnen. Infolgedessen existieren bereits zahlreiche Ansätze, sowohl software- als auch hardwareseitig, in denen diese Kombination realisiert wird. Allerdings haben die Bildinformationen bisher meist nur ergänzenden Charakter, beispielsweise bei der Kolorierung von Punktwolken oder der Texturierung von aus Laserscannerdaten erzeugten Oberflächenmodellen. Die konsequente Nutzung der komplementären Eigenschaften beider Sensortypen bietet jedoch ein weitaus größeres Potenzial. Aus diesem Grund wurde im Rahmen dieser Arbeit eine Berechnungsmethode – die integrierte Bündelblockausgleichung – entwickelt, bei dem die aus terrestrischen Laserscannerdaten und photogrammetrischen Bilddaten abgeleiteten Beobachtungen diskreter Objektpunkte gleichberechtigt Verwendung finden können. Diese Vorgehensweise hat mehrere Vorteile: durch die Nutzung der individuellen Eigenschaften beider Datentypen unterstützen sie sich gegenseitig bei der Bestimmung von 3D-Objektkoordinaten, wodurch eine höhere Genauigkeit erreicht werden kann. Alle am Ausgleichungsprozess beteiligten Daten werden optimal zueinander referenziert und die verwendeten Aufnahmegeräte können simultan kalibriert werden. Wegen des (sphärischen) Gesichtsfeldes der meisten terrestrischen Laserscanner von 360° in horizontaler und bis zu 180° in vertikaler Richtung bietet sich die Kombination mit Rotationszeilen-Panoramakameras oder Kameras mit Fisheye-Objektiv an, weil diese im Vergleich zu zentralperspektiven Kameras deutlich größere Winkelbereiche in einer Aufnahme abbilden können. Grundlage für die gemeinsame Auswertung terrestrischer Laserscanner- und photogrammetrischer Bilddaten ist die strenge geometrische Modellierung der Aufnahmegeräte. Deshalb wurde für terrestrische Laserscanner und verschiedene Kameratypen ein geometrisches Modell, bestehend aus einem Grundmodell und Zusatzparametern zur Kompensation von Restsystematiken, entwickelt und verifiziert. Insbesondere bei der Entwicklung des geometrischen Modells für Laserscanner wurden verschiedene in der Literatur beschriebene Ansätze berücksichtigt. Dabei wurde auch auf von Theodoliten und Tachymetern bekannte Korrekturmodelle zurückgegriffen. Besondere Bedeutung innerhalb der gemeinsamen Auswertung hat die Festlegung des stochastischen Modells. Weil verschiedene Typen von Beobachtungen mit unterschiedlichen zugrunde liegenden geometrischen Modellen und unterschiedlichen stochastischen Eigenschaften gemeinsam ausgeglichen werden, muss den Daten ein entsprechendes Gewicht zugeordnet werden. Bei ungünstiger Gewichtung der Beobachtungen können die Ausgleichungsergebnisse negativ beeinflusst werden. Deshalb wurde die integrierte Bündelblockausgleichung um das Verfahren der Varianzkomponentenschätzung erweitert, mit dem optimale Beobachtungsgewichte automatisch bestimmt werden können. Erst dadurch wird es möglich, das Potenzial der Kombination terrestrischer Laserscanner- und photogrammetrischer Bilddaten vollständig auszuschöpfen. Zur Berechnung der integrierten Bündelblockausgleichung wurde eine Software entwickelt, mit der vielfältige Varianten der algorithmischen Kombination der Datentypen realisiert werden können. Es wurden zahlreiche Laserscannerdaten, Panoramabilddaten, Fisheye-Bilddaten und zentralperspektive Bilddaten in mehreren Testumgebungen aufgenommen und unter Anwendung der entwickelten Software prozessiert. Dabei wurden verschiedene Berechnungsvarianten detailliert analysiert und damit die Vorteile und Einschränkungen der vorgestellten Methode demonstriert. Ein Anwendungsbeispiel aus dem Bereich der Geologie veranschaulicht das Potenzial des Algorithmus in der Praxis. / The use of terrestrial laser scanning has grown in popularity in recent years, and replaces and complements previous measuring methods, as well as opening new fields of application. If data from terrestrial laser scanners are combined with photogrammetric image data, this yields promising possibilities, as the properties of both types of data can be considered mainly complementary: terrestrial laser scanners produce fast and reliable three-dimensional representations of object surfaces from only one position, while two-dimensional photogrammetric image data are characterised by a high visual quality, ease of interpretation, and high lateral accuracy. Consequently there are numerous approaches existing, both hardware- and software-based, where this combination is realised. However, in most approaches, the image data are only used to add additional characteristics, such as colouring point clouds or texturing object surfaces generated from laser scanner data. A thorough exploitation of the complementary characteristics of both types of sensors provides much more potential. For this reason a calculation method – the integrated bundle adjustment – was developed within this thesis, where the observations of discrete object points derived from terrestrial laser scanner data and photogrammetric image data are utilised equally. This approach has several advantages: using the individual characteristics of both types of data they mutually strengthen each other in terms of 3D object coordinate determination, so that a higher accuracy can be achieved; all involved data sets are optimally co-registered; and each instrument is simultaneously calibrated. Due to the (spherical) field of view of most terrestrial laser scanners of 360° in the horizontal direction and up to 180° in the vertical direction, the integration with rotating line panoramic cameras or cameras with fisheye lenses is very appropriate, as they have a wider field of view compared to central perspective cameras. The basis for the combined processing of terrestrial laser scanner and photogrammetric image data is the strict geometric modelling of the recording instruments. Therefore geometric models, consisting of a basic model and additional parameters for the compensation of systematic errors, was developed and verified for terrestrial laser scanners and different types of cameras. Regarding the geometric laser scanner model, different approaches described in the literature were considered, as well as applying correction models known from theodolites and total stations. A particular consideration within the combined processing is the definition of the stochastic model. Since different types of observations with different underlying geometric models and different stochastic properties have to be adjusted simultaneously, adequate weights have to be assigned to the measurements. An unfavourable weighting can have a negative influence on the adjustment results. Therefore a variance component estimation procedure was implemented in the integrated bundle adjustment, which allows for an automatic determination of optimal observation weights. Hence, it becomes possible to exploit the potential of the combination of terrestrial laser scanner and photogrammetric image data completely. For the calculation of the integrated bundle adjustment, software was developed allowing various algorithmic configurations of the different data types to be applied. Numerous laser scanner, panoramic image, fisheye image and central perspective image data were recorded in different test fields and processed using the developed software. Several calculation alternatives were analysed, demonstrating the advantages and limitations of the presented method. An application example from the field of geology illustrates the potential of the algorithm in practice.

No description available.

Pheroid is a patented system comprising of a unique submicron emulsion type formulation. Pheroid vesicles consist mainly of plant and essential fatty acids and can entrap, transport and deliver pharmacologically active compounds and other useful molecules. The aim of this study was to show that a modulation of components and parameters is necessary to obtain the optimum formula to be used in pharmaceutical preparations. Non-optimal or non-predictable stability properties of emulsions can be limiting for the applications of emulsions (Bjerregaard et al., 2001:23). Careful consideration was given to the apparatus used during the processing along with the ratios of the various components added to the formulation and the storage conditions of the Pheroid vesicles. A preliminary study was performed to optimize the most accurate processing parameters during emulsification. The effect of emulsification rate and time, the temperature of the aqueous phase, the number of days the water phase were gassed, the concentration of the surfactant, cremophor® RH 40, used and the concentration of Vitamin F Ethyl Ester CLR added to the oil phase of the o/w emulsion has been studied. Quantification of the mean particle size, zeta potential, turbidity, pH and current values were used to characterize the emulsions. The samples were characterised after 1, 2, 3, 7, 14, 21 and 28 days of storage. The emulsions were also characterised with confocal laser scanning microscopy (CLSM) to measure the number and size and size distribution of the vesicles. After determination of the processing variables influencing the emulsion stability an accelerated stability test was conducted on a final formula. In the present study, accelerated stability testing employing elevated temperatures and relative humidity were used with good accuracy to predict long-term stability of an o/w emulsion kept at both 5 and 25 OC with 60 % relative humidity and 40 OC with 75 % relative humidity. The results of the stability tests were presented in histograms of the physical properties 24 hours, 1 month, 2 months and 3 months after preparation of the emulsion. It was concluded that Pheroid vesicles demonstrate much potential as a drug delivery system. The high stability of this formula allows its use in a wide variety of applications in the pharmaceutical industry. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.

Pheroid is a patented system comprising of a unique submicron emulsion type formulation. Pheroid vesicles consist mainly of plant and essential fatty acids and can entrap, transport and deliver pharmacologically active compounds and other useful molecules. The aim of this study was to show that a modulation of components and parameters is necessary to obtain the optimum formula to be used in pharmaceutical preparations. Non-optimal or non-predictable stability properties of emulsions can be limiting for the applications of emulsions (Bjerregaard et al., 2001:23). Careful consideration was given to the apparatus used during the processing along with the ratios of the various components added to the formulation and the storage conditions of the Pheroid vesicles. A preliminary study was performed to optimize the most accurate processing parameters during emulsification. The effect of emulsification rate and time, the temperature of the aqueous phase, the number of days the water phase were gassed, the concentration of the surfactant, cremophor® RH 40, used and the concentration of Vitamin F Ethyl Ester CLR added to the oil phase of the o/w emulsion has been studied. Quantification of the mean particle size, zeta potential, turbidity, pH and current values were used to characterize the emulsions. The samples were characterised after 1, 2, 3, 7, 14, 21 and 28 days of storage. The emulsions were also characterised with confocal laser scanning microscopy (CLSM) to measure the number and size and size distribution of the vesicles. After determination of the processing variables influencing the emulsion stability an accelerated stability test was conducted on a final formula. In the present study, accelerated stability testing employing elevated temperatures and relative humidity were used with good accuracy to predict long-term stability of an o/w emulsion kept at both 5 and 25 OC with 60 % relative humidity and 40 OC with 75 % relative humidity. The results of the stability tests were presented in histograms of the physical properties 24 hours, 1 month, 2 months and 3 months after preparation of the emulsion. It was concluded that Pheroid vesicles demonstrate much potential as a drug delivery system. The high stability of this formula allows its use in a wide variety of applications in the pharmaceutical industry. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.

Research on forest ecosystems receives high attention, especially nowadays with regard to sustainable management of renewable resources and the climate change. In particular, accurate information on the 3D structure of a tree is important for forest science and bioclimatology, but also in the scope of commercial applications. Conventional methods to measure geometric plant features are labor- and time-intensive. For detailed analysis, trees have to be cut down, which is often undesirable. Here, Terrestrial Laser Scanning (TLS) provides a particularly attractive tool because of its contactless measurement technique. The object geometry is reproduced as a 3D point cloud. The objective of this thesis is the automatic retrieval of the spatial structure of trees from TLS data. We focus on forest scenes with comparably high stand density and with many occlusions resulting from it. The varying level of detail of TLS data poses a big challenge. We present two fully automatic methods to obtain skeletal structures from scanned trees that have complementary properties. First, we explain a method that retrieves the entire tree skeleton from 3D data of co-registered scans. The branching structure is obtained from a voxel space representation by searching paths from branch tips to the trunk. The trunk is determined in advance from the 3D points. The skeleton of a tree is generated as a 3D line graph. Besides 3D coordinates and range, a scan provides 2D indices from the intensity image for each measurement. This is exploited in the second method that processes individual scans. Furthermore, we introduce a novel concept to manage TLS data that facilitated the researchwork. Initially, the range image is segmented into connected components. We describe a procedure to retrieve the boundary of a component that is capable of tracing inner depth discontinuities. A 2D skeleton is generated from the boundary information and used to decompose the component into sub components. A Principal Curve is computed from the 3D point set that is associated with a sub component. The skeletal structure of a connected component is summarized as a set of polylines. Objective evaluation of the results remains an open problem because the task itself is ill-defined: There exists no clear definition of what the true skeleton should be w.r.t. a given point set. Consequently, we are not able to assess the correctness of the methods quantitatively, but have to rely on visual assessment of results and provide a thorough discussion of the particularities of both methods. We present experiment results of both methods. The first method efficiently retrieves full skeletons of trees, which approximate the branching structure. The level of detail is mainly governed by the voxel space and therefore, smaller branches are reproduced inadequately. The second method retrieves partial skeletons of a tree with high reproduction accuracy. The method is sensitive to noise in the boundary, but the results are very promising. There are plenty of possibilities to enhance the method’s robustness. The combination of the strengths of both presented methods needs to be investigated further and may lead to a robust way to obtain complete tree skeletons from TLS data automatically. / Die Erforschung des ÖkosystemsWald spielt gerade heutzutage im Hinblick auf den nachhaltigen Umgang mit nachwachsenden Rohstoffen und den Klimawandel eine große Rolle. Insbesondere die exakte Beschreibung der dreidimensionalen Struktur eines Baumes ist wichtig für die Forstwissenschaften und Bioklimatologie, aber auch im Rahmen kommerzieller Anwendungen. Die konventionellen Methoden um geometrische Pflanzenmerkmale zu messen sind arbeitsintensiv und zeitaufwändig. Für eine genaue Analyse müssen Bäume gefällt werden, was oft unerwünscht ist. Hierbei bietet sich das Terrestrische Laserscanning (TLS) als besonders attraktives Werkzeug aufgrund seines kontaktlosen Messprinzips an. Die Objektgeometrie wird als 3D-Punktwolke wiedergegeben. Basierend darauf ist das Ziel der Arbeit die automatische Bestimmung der räumlichen Baumstruktur aus TLS-Daten. Der Fokus liegt dabei auf Waldszenen mit vergleichsweise hoher Bestandesdichte und mit zahlreichen daraus resultierenden Verdeckungen. Die Auswertung dieser TLS-Daten, die einen unterschiedlichen Grad an Detailreichtum aufweisen, stellt eine große Herausforderung dar. Zwei vollautomatische Methoden zur Generierung von Skelettstrukturen von gescannten Bäumen, welche komplementäre Eigenschaften besitzen, werden vorgestellt. Bei der ersten Methode wird das Gesamtskelett eines Baumes aus 3D-Daten von registrierten Scans bestimmt. Die Aststruktur wird von einer Voxelraum-Repräsentation abgeleitet indem Pfade von Astspitzen zum Stamm gesucht werden. Der Stamm wird im Voraus aus den 3D-Punkten rekonstruiert. Das Baumskelett wird als 3D-Liniengraph erzeugt. Für jeden gemessenen Punkt stellt ein Scan neben 3D-Koordinaten und Distanzwerten auch 2D-Indizes zur Verfügung, die sich aus dem Intensitätsbild ergeben. Bei der zweiten Methode, die auf Einzelscans arbeitet, wird dies ausgenutzt. Außerdem wird ein neuartiges Konzept zum Management von TLS-Daten beschrieben, welches die Forschungsarbeit erleichtert hat. Zunächst wird das Tiefenbild in Komponenten aufgeteilt. Es wird eine Prozedur zur Bestimmung von Komponentenkonturen vorgestellt, die in der Lage ist innere Tiefendiskontinuitäten zu verfolgen. Von der Konturinformation wird ein 2D-Skelett generiert, welches benutzt wird um die Komponente in Teilkomponenten zu zerlegen. Von der 3D-Punktmenge, die mit einer Teilkomponente assoziiert ist, wird eine Principal Curve berechnet. Die Skelettstruktur einer Komponente im Tiefenbild wird als Menge von Polylinien zusammengefasst. Die objektive Evaluation der Resultate stellt weiterhin ein ungelöstes Problem dar, weil die Aufgabe selbst nicht klar erfassbar ist: Es existiert keine eindeutige Definition davon was das wahre Skelett in Bezug auf eine gegebene Punktmenge sein sollte. Die Korrektheit der Methoden kann daher nicht quantitativ beschrieben werden. Aus diesem Grund, können die Ergebnisse nur visuell beurteiltwerden. Weiterhinwerden die Charakteristiken beider Methoden eingehend diskutiert. Es werden Experimentresultate beider Methoden vorgestellt. Die erste Methode bestimmt effizient das Skelett eines Baumes, welches die Aststruktur approximiert. Der Detaillierungsgrad wird hauptsächlich durch den Voxelraum bestimmt, weshalb kleinere Äste nicht angemessen reproduziert werden. Die zweite Methode rekonstruiert Teilskelette eines Baums mit hoher Detailtreue. Die Methode reagiert sensibel auf Rauschen in der Kontur, dennoch sind die Ergebnisse vielversprechend. Es gibt eine Vielzahl von Möglichkeiten die Robustheit der Methode zu verbessern. Die Kombination der Stärken von beiden präsentierten Methoden sollte weiter untersucht werden und kann zu einem robusteren Ansatz führen um vollständige Baumskelette automatisch aus TLS-Daten zu generieren.

Accurate and frequent construction progress tracking provides critical input data for project systems such as cost and schedule control as well as billing. Unfortunately, conventional progress tracking is labor intensive, sometimes subject to negotiation, and often driven by arcane rules. Attempts to improve progress tracking have recently focused mainly on automation, using technologies such as 3D imaging, Global Positioning System (GPS), Ultra Wide Band (UWB) indoor locating, hand-held computers, voice recognition, wireless networks, and other technologies in various combinations. Three dimensional (3D) imaging technologies, such as 3D laser scanners (LADARs) and photogrammetry have shown great potential for saving time and cost for recording project 3D status and thus to support some categories of progress tracking. Although laser scanners in particular and 3D imaging in general are being investigated and used in multiple applications in the construction industry, their full potential has not yet been achieved. The reason may be that commercial software packages are still too complicated and time consuming for processing scanned data. Methods have however been developed for the automated, efficient and effective recognition of project 3D BIM objects in site laser scans. This thesis presents a novel system that combines 3D object recognition technology with schedule information into a combined 4D object based construction progress tracking system. The performance of the system is investigated on a comprehensive field database acquired during the construction of a steel reinforced concrete structure, Engineering V Building at the University of Waterloo. It demonstrates a degree of accuracy that meets or exceeds typical manual performance. However, the earned value tracking is the most commonly used method in the industry. That is why the object based automated progress tracking system is further explored, and combined with earned value theory into an earned value based automated progress tracking system. Nevertheless, both of these systems are focused on permanent structure objects only, not secondary or temporary. In the last part of the thesis, several approaches are proposed for concrete construction secondary and temporary object tracking. It is concluded that accurate tracking of structural building project progress is possible by combining a-priori 4D project models with 3D object recognition using the algorithms developed and presented in this thesis.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-14T12:14:47Z No. of bitstreams: 1 PGEF17MA076.pdf: 1708102 bytes, checksum: 322df030779727eab396b8c422e27499 (MD5) / Made available in DSpace on 2017-12-14T12:14:47Z (GMT). No. of bitstreams: 1 PGEF17MA076.pdf: 1708102 bytes, checksum: 322df030779727eab396b8c422e27499 (MD5) Previous issue date: 2017-02-24 / PROMOP / CAPES / Through the morphometric indices one can infer about the necessary space that the species needs to develop, maintain its growth and production rates. Allied to this, diametric growth information can portray competition in a stand, indicating the need for management practices. Objective of the proposed study to analyze the morphometry and behavior of the development and diametric increase of Araucária angustifolia through dendrochronology. In addition, data collected in the field were compared with information generated by cloud of points captured by the terrestrial Laser scanner equipment. For an analysis of the morphometry data were collected from 121 individual trees, for the purpose 127 samples and how to evaluate the information Laser 18 individuals sampled. Araucarias belong to two sites in the municipality of São José do Cerrito, in Santa Catarina. (Dc), height (h), crown height (Hc), crown radius (Rc), crown length (Cc), crown diameter (IS), the degree of slenderness (GE), the formal crown (Fc), crown ratio (Pc%), crown area (Ac) and sociological position (s) In addition to removal of increment rolls. For the morphometric relationships, 11 significant correlations were obtained and as 5 higher correlations (Dap, hic, Cc, Dc, Pc%, IA and GE) were adjusted for their determination, logarithmic E. A covariance analysis was found to exist in the morphometric relationships evaluated for each case sampled. (PS2) 0.223 m2 and dominated (PS3) 0.356 m2. For site 2, PS1 had a mean of 0.381 m2, PS2 0.360 m2 and PS3 0.300 m2. The study showed that IPAd is correlated with canopy characteristics, being a hic, Cc, Pc (%) and GE. A means of communication between variable, dendrometric and morphological means, by traditional methods of measurement and captured by Laser station, did not present significant difference between them. However, the methodologies proposed in literature are susceptible to failures, mainly, by the influence of points that do not correspond to the surface of the tree. However, the shape of the crown for each class of Dap showed that the species has different contours throughout its development stage, characterizing a conical cup in the juvenile phase, and with a maturity or shape tend to be configured in a flat way, or Then identifying a shape of umbel. For the methodologies to be comprehensive for a species, the case studies are as follows, the analyzes are welcome, the diametral amplitude is greater for the inferences, besides evaluating the viability of the images generated by the Scanning terrestrial laser scanner in the Forest mensuration / Através dos índices da morfometria pode-se inferir sobre o espaço necessário que determinada espécie necessita para se desenvolver, manter suas taxas de crescimento e produção. Aliado a isso, informações de crescimento diamétrico conseguem retratar quadro de competição em um povoamento, indicando a necessidade de práticas de manejo. O objetivo do estudo proposto foi analisar a morfometria e o comportamento do desenvolvimento e incremento diamétrico de Araucaria angustifolia através da dendrocronologia. Além disso, foram comparados dados coletados em campo com informações geradas pela nuvem de pontos captada pelo equipamento Laser scanner terrestre. Para a análise da morfometria foram coletados dados de 121 árvores individuais, para incremento foram utilizadas 127 árvores e para avaliar as informações Laser 18 indivíduos amostrados. As araucárias pertenciam a dois sítios no município de São José do Cerrito, em Santa Catarina. Foram mensuradas as variáveis: diâmetro a altura do peito (Dap), altura (h), altura de início de copa (hic), raio de copa (Rc), comprimento de copa (Cc), diâmetro de copa (Dc), índice de abrangência (IA), índice de saliência (IS), grau de esbeltez (GE), formal de copa (Fc), proporção de copa (Pc%), área de copa (Ac) e a posição sociológica (s) de cada indivíduo, além da retirada de rolos de incremento. Para as relações morfométricas obteve-se 11 correlações significativas e para as 5 maiores correlações (Dap, hic, Cc, Dc, Pc%, IA e GE) foram ajustados modelos para sua determinação, sendo caracterizados com distribuição gama e normal, e funções identidade e logarítmica. A análise de covariância demonstrou existir diferenças nas relações morfométricas avaliadas para cada sítio amostrado. Para a análise do incremento periódico anual em diâmetro (IPAd), o sítio 1, em árvores dominantes (PS1) teve média de 0,235 m2, codominantes (PS2) 0,223 m2 e dominadas (PS3) 0,356 m2. Para o sitio 2, PS1 teve média de 0,381 m2, PS2 0,360 m2 e PS3 0,300 m2. O estudo mostrou que IPAd está correlacionado com as características da copa, sendo elas, a hic, Cc, Pc(%) e o GE. A comparação entre as médias das variáveis dendrométricas e morfométricas, pelos métodos de mensuração, tradicional e captado pela estação Laser, não apresentaram diferença significativa entre si. Porém, as metodologias propostas em literatura estão suscetíveis a falhas, principalmente, pela influência de pontos que não correspondem a superfície da árvore. Já para o formato da copa para cada classe de Dap mostrou que a espécie possui diferentes contornos ao longo do seu estágio de desenvolvimento, caracterizando uma copa cônica na fase juvenil, e com a maturidade o formato tende a configurar-se de maneira plana, ou então identificando uma forma de umbela. Para que as metodologias sejam abrangentes a espécie, são necessários estudos que incluem diferentes sítios amostrais, bem como, uma amplitude diamétrica maior para gerar inferências, além de avaliar a viabilidade do uso de imagens geradas pela varredura Laser scanner terrestre na mensuração florestal

Orientador: Aluir Porfírio Dal Poz / Banca: Nilton Nobuhiro Imai / Banca: Maurício Galo / Banca: Edson Aparecido Mitishita / Resumo: As metodologias para a extração automática de telhados desempenham um papel importante no contexto de aquisição de informação espacial para Sistemas de Informação Geográficas (SIG). Neste sentido, este trabalho propõe uma metodologia para extração automática de contornos de telhado de edifícios utilizando dados de varredura a laser. A metodologia baseiase em duas etapas principais: 1) Extração de regiões altas (edifícios, árvores etc.) de um Modelo Digital de Elevação (MDE) gerado a partir dos dados laser; 2) Extração das regiões altas que correspondem a contornos de telhados. Na primeira etapa são utilizadas as técnicas de divisão recursiva, via estrutura quadtree e de fusão Bayesiana de regiões considerando Markov Random Field (MRF). Inicialmente a técnica de divisão recursiva é usada para particionar o MDE em regiões homogêneas. No entanto, devido a ligeiras diferenças de altura no MDE, nesta etapa a fragmentação das regiões pode ser relativamente alta. Para minimizar essa fragmentação, a técnica de fusão Bayesiana de regiões é aplicada nos dados segmentados. Utiliza-se para tanto um modelo hierárquico, cujas alturas médias das regiões dependem de uma média geral e de um efeito aleatório, que incorpora a relação de vizinhança entre elas. A distribuição a priori para o efeito aleatório é especificada como um modelo condicional auto-regressivo (CAR). As distribuições a posteriori para os parâmetros de interesse foram obtidas utilizando o Amostrador de Gibbs. Na segunda etapa os contornos de telhados são identificados entre todos os objetos altos extraídos na etapa anterior. Levando em conta algumas propriedades de telhados e as medidas de alguns atributos (por exemplo, área, retangularidade, ângulos entre eixos principais de objetos) é construída uma função de energia a partir do modelo MRF. / Abstract: Methodologies for automatic building roof extraction are important in the context of spatial information acquisition for geographical information systems (GIS). Thus, this work proposes a methodology for automatic extraction of building roof contour from laser scanning data. The methodology is based on two stages: 1) Extraction of high regions (buildings, trees etc.) from a Digital Elevation Model (DEM) derived from laser scanning data; 2) Building roof contour extraction. In the first stage is applied the recursive splitting technique using the quadtree structure followed by a Bayesian merging technique considering Markov Random Field (MRF) model. The recursive splitting technique subdivides the DEM into homogeneous regions. However, due to slight height differences in the DEM, in this stage the region fragmentation can be relatively high. In order to minimize the fragmentation, a region merging technique based on the Bayesian framework is applied to the previously segmented data. Thus, a hierarchical model is proposed, whose height values in the data depend on a general mean plus a random effect. The prior distribution for the random effects is specified by the Conditional Autoregressive (CAR) model. The posterior probability distributions are obtained by the Gibbs sampler. In the second stage the building roof contours are identified among all high objects extracted previously. / Doutor

The utilisation of 3D digitisation and visualisation has grown considerably since 2008 and is becoming an increasingly useful tool for the digital documentation and metric analysis of archaeological artefacts and skeletal remains. It provides public access to rare and fragile specimens of palaeontological and palaeopathological importance whilst reducing the physical impact on these remains. Research in engineering and computer vision provides some insight into the impact of surface properties such as colour, specularity, reflectance and shape on the quality of the recorded 3D image, but within the archaeological and palaeontological disciplines comparable work has not yet been developed. If archaeology and anthropology are to provide long term reliable data from archaeological and palaeontological specimens in a way that doesn’t require repeated re-digitisation, we need to understand the impacts that the taphonomic histories of such samples have on our ability to 3D record them. Understanding the relationship of these taphonomic histories and the surface and optical properties will promote informed choices about the suitability of recording techniques. This thesis considers the taphonomic processes that affect the preservation of bone over archaeological, forensic and palaeontological timescales and the effect this has on the quality of 3D digital models. The digital refit of fragmentary bone samples is considered in relation to the effect of taphonomic alterations to bone. Conclusions regarding the key taphonomic factors and 3D digital model quality are drawn and areas of further work are identified.

När kraven på mätosäkerhet är hög vid geodetiska mätningar behövs geodetiska referenssystem realiserade av geodetiska nät av hög kvalitet. Etableringen och transformation till överordnade referenssystem i höjd av dessa nät genomförs idag ofta med terrestra metoder som avvägning, vilket är ett noggrant men tidskrävande arbete. Det finns flera försök att använda sig av andra metoder såsom GNSS, men en möjlighet skulle även vara att använda punktmoln från flygburen laserskanning. Detta arbetes syfte är att undersöka om punktmoln kan användas till transformation av ett geodetiskt höjdnät i Sandvikens kommun. Nätet består av cirka 500 fixpunkter och har 2010 transformerats till RH2000 av Lantmäteriet. Det använda punktmolnet har producerats av Lantmäteriet och har en medelavvikelse om 0,05 m på plana hårdgjorda ytor. Detta är relativt högt då vanligen osäkerheter på millimeternivå önskas vid transformationer. Men eftersom medeltal kan reducera slumpmässiga avvikelser i enskilda mätningar kan en transformation bestående av ett medelhöjdskift möjligen ge ett tillfredsställande resultat. Medelhöjdskiftet är då ett medeltal av flera höjdskift beräknade på olika ställen i punktmolnet. Genom att avväga höjdskillnaden mellan fixpunkterna i nätet och punkter på markytan som med olika metoder höjdbestäms utifrån punktmolnet har höjder för fixpunkterna enligt punktmolnet erhållits. Dessa har jämförts med RH2000 höjder enligt Lantmäteriets transformation för att beräkna en avvikelse, samt med de äldre lokala höjderna för att beräkna ett höjdskift. Genom att beräkna medelvärde och dess osäkerhet för höjdskiftet över hela nätet har en uppfattning om metodens lämplighet erhållits. Höjdskiften låg överlag inom några millimeter från det som Lantmäteriet beräknat, med 3 mm osäkerhet för den överlag bästa metoden. Även om höjdskiftets och därmed transformationens osäkerhet delvis blev något hög jämfört med avvägning så kan punktmoln ändå vara ett lämpligt alternativ. Speciellt i mera avlägsna områden utan bra anknytningar till det överordnade nätet kan det vara intressant. Det finns dock många parametrar som ännu inte utforskats, bland annat vissa eventuella systematiska avvikelser. / When the requirements on accuracy and precision are high for geodetic measurements you need geodetic reference systems realized with geodetic control networks of high quality. Today, establishment and transformation to higher order reference systems for height usually uses terrestrial methods like levelling. While highly accurate these result in time consuming work. There have been a couple attempts at using other methods for this task, for example GNSS, but another possibility might be usage of point clouds from airborne laser scanning. As a starting point for further studies this study attempts to use point clouds to transform a geodetic height network in Sandviken municipality, Sweden. The network consists of around 500 benchmarks and has been transformed to the national reference system for height, RH2000, by the Swedish national geodetic survey (Lantmäteriet) in 2010. The point cloud used is also produced by Lantmäteriet and is said to have a mean error of 0,05 m. This is relatively high since the requirements usually are in the millimeter range when determining transformation parameters, but if the transformation only consist of a single height shift calculated as a mean from several height shifts derived from the point cloud any random errors in the point cloud should be reduced. By measuring the height difference between benchmarks and points on the ground, that through different methods are given heights according to the point cloud, heights of the benchmarks have been determined according according to the point cloud. These can be compared to heights in RH2000 according to the transformation performed by Lantmäteriet to see their deviation from the assumed true value. Further comparisons against the older local heights of the benchmarks give a height shift that can be used as a simple transformation. By calculating a mean and uncertainty an estimation of the suitability of the method can be achieved. The all height shifts deviated a few millimeters from the result Lantmäteriet got, with uncertainties around 3 mm for the overall best method. Even if the uncertainty of the shift and therefore the transformation ended up somewhat high compared to what Lantmäteriet achieved it is still believed that point clouds may be or become a viable alternative. Especially in more remote regions without good connections to the higher order network. There are many parameters that have not yet been explored though, as well as some potential systematic errors that should be further investigated.