The maintenance of infrastructure is critical to the well-being of society. This work focuses on a novel method for inspecting the exterior of dams using unmanned aerial vehicles (UAVs) in an automated fashion. The UAVs are equipped with optical sensors capturing still images. The resulting images are used to generate three-dimensional (3D) models using Structure from Motion (SfM) computer software. The SfM models are then used to inspect the exterior of the dam. As typical dam inspections entail completing a checklist of inspection items with varied degrees of precision (e.g. a concrete spillway may be finely inspected for cracking or joint deterioration while the general stability and water-tightness of a large embankment may be observed from a distance), a targeted inspection is also needed for the UAV method. In conjunction with the work presented in this thesis, a novel algorithm was developed which uses camera view planning across multiple proximity levels to generate a set of camera poses (positions and orientations) which can be collected in an autonomous UAV flight that facilitates generation of SfM models having tiered model quality for targeted inspection of infrastructure features. In this thesis, this novel algorithm and accompanying mobile application (referred to together as the novel advanced autonomous method) were field validated at Tibble Fork Dam, UT. The advanced autonomous method was compared to two other common image acquisition methods—basic autonomous and manual piloted—based on the SfM models produced from the collected image sets. The advanced autonomous method was found to produce models having tiered quality needed for efficient targeted inspection (25% and 50% higher resolution in medium and high priority target areas). The advanced autonomous method was found to produce models having on average 38% higher precise point accuracy (1.3cm) and 53% tighter surface reproducibility (for repeat inspections) (1.9cm) than basic autonomous and manual piloted image acquisition methods. The advanced autonomous method required on average 167% longer flight time and 38% fewer images than the other two methods, resulting in increased field time but decreased processing load. Additionally, viability of the advanced autonomous method for practical dam inspection was assessed through a case study inspection of Tibble Fork Dam using the collected SfM model and corresponding still images. The SfM model and corresponding images were found fully adequate for performing 94% of the inspection tasks and partially adequate for the remaining tasks. In consideration of this and other practical implementation factors such as time and safety, the method appears highly viable as an alternate to or supplement with traditional on-foot visual exterior inspection of dams such as Tibble Fork Dam. Suggestions for future work include adjustments to the optimization framework to improve field efficiency, development of a framework for cooperative inspection using UAV swarms, and development of a more automated workflow that would allow fully-remote dam inspections.

Hermatypic, or reef-building, corals (Order Scleractinia) are the foundation of coral reefs, providing a diversity of structurally complex habitats for the myriad species in these biologically diverse ecosystems. However, both local and global anthropogenic stressors threaten the persistence of these corals. For this thesis, thirty 16m2 permanent photoquadrats at 10 shallow forereef sites around Kiritimati (Christmas Island, Republic of Kiribati) were monitored across a four-year study encompassing the 2015-2016 El Niño derived marine heatwave, and subsequent mass coral mortality event. Sites were exposed to either low, medium, or high levels of local anthropogenic disturbance. My objective herein was to examine the effects of a mass coral mortality event on reef structural complexity, from the end of the event to three years afterwards. To do so, I digitally quantified six metrics of structural complexity for each photoquadrat sampled across three resolution scales for each of the five expeditions. Plots from 2015, 2017, and 2019 were later annotated based on the morphological structure present. I found that while significant declines in multiple of habitat metrics occurred by the end of the heatwave, no further significant declines occurred thereafter. However, this trend was lost as resolution scale increased, indicating the trends seen in the habitat metrics at 1.0 cm were likely documenting the shift from live coral towards abiotic dominated reefs. Anthropogenic disturbance compounded the El Niño’s effect, ensuring high disturbance sites had the lowest structural complexity values throughout the study. Lastly, live branching, tabulate, foliose, and submassive coral morphologies were found to be most closely associated with the different habitat complexity metrics. These results highlight the importance live coral structure has on reef structural complexity, illustrate the importance of model resolution when quantifying trends in structural complexity, pinpoint coral morphologies creating reef structural complexity, and further emphasize the need to limit the effects of local anthropogenic disturbance on coral reefs. / Graduate / 2023-04-15

Perception of depth, ego-motion and robust keypoints is critical for SLAM andstructure from motion applications. Neural networks have achieved great perfor-mance in perception tasks in recent years. But collecting labeled data for super-vised training is labor intensive and costly. This thesis explores recent methodsin unsupervised training of neural networks that can predict depth, ego-motion,keypoints and do geometric consensus maximization. The benefit of unsuper-vised training is that the networks can learn from raw data collected from thecamera sensor, instead of labeled data. The thesis focuses on training on imagesfrom a monocular camera, where no stereo or LIDAR data is available. The exper-iments compare different techniques for depth and ego-motion prediction fromprevious research, and shows how the techniques can be combined successfully.A keypoint prediction network is evaluated and its performance is comparedwith the ORB detector provided by OpenCV. A geometric consensus network isalso implemented and its performance is compared with the RANSAC algorithmin OpenCV. The consensus maximization network is trained on the output of thekeypoint prediction network. For future work it is suggested that all networkscould be combined and trained jointly to reach a better overall performance. Theresults show (1) which techniques in unsupervised depth prediction are most ef-fective, (2) that the keypoint predicting network outperformed the ORB detector,and (3) that the consensus maximization network was able to classify outlierswith comparable performance to the RANSAC algorithm of OpenCV.

Bathymetric mapping is an important tool for reservoir management, typically completed before reservoir construction. Historically, bathymetric maps were produced by interpolating between points measured at a relatively large spacing throughout a reservoir, typically on the order of a few, up to 10, meters or more depending on the size of the reservoir. These measurements were made using traditional survey methods before the reservoir was filled, or using sonar surveys after filling. Post-construction issues such as sedimentation and erosion can change a reservoir, but generating updated bathymetric maps is difficult as the areas of interest are typically in the sediment deltas and other difficult-to-access areas that are often above water or exposed for part of the year. We present a method to create complete reservoir bathymetric maps, including areas above the water line, using small unmanned aerial vehicle (sUAV) photogrammetry combined with multi-beam sonar data--both established methods for producing topographic models. This thesis presents methods to create accurate above-water shoreline models using images from sUAVs, processed using a commercial software package and a method to accurately knit sonar and Structure from Motion (SfM) data sets by matching slopes. The models generated by both approaches are point clouds, which consist of points representing the ground surface in three-dimensional space. Generating models from sUAV-captured images requires ground control points (GCPs), i.e., points with a known location, to anchor model creation. We explored issues with ground control spacing, masking water regions (or omitting water regions) in the images, using no GCPs, and incorrectly tagging a GCP. To quantify the effect these issues had on model accuracy, we computed the difference between generated clouds and a reference point cloud to determine the point cloud error. We found that the time required to place GCPs was significantly more than the time required to capture images, so optimizing GCP density is important. We found that we needed to mask water and areas related to distant regions and sky in images used for model creation. This is because water, objects in the far oblique distance, and sky confuse the algorithms that match points among images. Our sonar point clouds, while self-consistent, were not accurately georeferenced. We demonstrate a method using cross-sections of the transition between the above-water clouds and sonar clouds to geo-locate the sonar data and accurately knit the two data sets. Shore line topography models and integration of sonar and drone data is a niche area that leverages current advances in data collection and processing. Our work was applied at three different reservoirs to show that accurate post-construction reservoir bathometry maps can assist with reservoir management. A report is included that compares historical bathymetric maps with the current bathymetric maps at each of the three different reservoirs. A guide to perform the drone surveys is included in the report's appendix.

An integrated program has been developed to explore the reactivity of 2:1 phyllosilicates (biotite and the clays montmorillonite, hectorite, and nontronite) with respect to acid dissolution using in situ atomic force microscopy (AFM). Three techniques are described which make it possible to fix these minerals and other small particles to a suitable substrate for examination in the fluid cell of the atomic force microscope. A suite of macros has also been developed for the Image SXM image analysis environment which make possible the accurate and consistent measurement of the dimensions of clay particles in a series of AFM images, so that dissolution rates can be measured during a fluid cell experiment. Particles of biotite and montmorillonite were dissolved, and their dissolution rates normalized to their reactive surface area, which corresponds to the area of their edge surfaces (A_e). The A_e-normalized rates for these minerals between pH 1-2 are all ~10E^-8 mol/m²*s, and compare very well to other A_e-normalized dissolution rates in the literature. Differences between the A_e-normalized rates for biotite and the BET-normalized rates (derived from solution chemical studies) found in the literature can be easily explained in terms of the proportion of edge surface area and the formation of leached layers. However, the differences between the A_e-normalized montmorillonite rates and the literature values cannot be explained the same way. Rather, it is demonstrated that rates derived from solution studies of montmorillonite dissolution have been affected by the colloidal behavior of the mineral particles. Finally, the dissolution behavior of hectorite (a trioctahedral smectite) and nontronite ( a dioctahedral smectite) were compared. Based on the differential reactivity of their crystal faces, a model of their surface atomic structures is formulated using Hartman-Perdock crystal growth theory, which explains the observed data if it is assumed that the rate-determining step of the dissolution mechanism is the breaking of connecting bonds between the octahedral and tetrahedral sheets of the mineral structure. / Ph. D.

En este trabajo se ha desarrollado un microscopio de fuerzas (SFM) provisto de microscopía electrostática (ESFM) y microscopía Kelvin (KPM) especialmente diseñado para integrarse en un microscopio óptico invertido de forma que combine simultáneamente las técnicas de campo cercano con las técnicas ópticas. Tras una introducción (capítulo 1) y la descripción de las técnicas experimentales (capítulo 2), se detallan las características del diseño de un primer prototipo, así como las medidas realizadas con él con el fin de comprobar su correcto funcionamiento (capítulo 3). El capítulo 4 muestra el diseño de un segundo prototipo con las mejoras que incorpora respecto al primero, que lo convierten en un sistema más completo, versátil y fácil de manejar. También figuran las medidas realizadas con él. El capítulo 5 muestra un estudio de fotodegradación en polímeros conductores en función de la radiación incidente, combinando microscopía electrostática y Kelvin con técnicas ópticas. / In this work we have developed an Scanning Force Microscope (SFM) equipped with Electrostatic and Kelvin Probe Microscopy (ESFM, KPM), specially designed for integration into an inverted optical microscope in order to combine near-field techniques with optical techniques. After an introduction (Chapter 1) and the description of the experimental techniques (Chapter 2), are described the features of the design of a first prototype, as well as the measurements made with it in order to verify proper operation (Chapter 3). The Chapter 4 shows the design of a second prototype that incorporates the improvements over the first, making it more comprehensive, versatile and easy to handle. Also are shown the measurements performed with it. The Chapter 5 shows a photodegradation study of conductive polymers as a function of incident radiation combining KPM with optical techniques.

Synthetic biomaterials are constantly being developed and play central roles in contemporary strategies in regenerative medicine and tissue engineering as artificial extracellular microenvironments. Such scaffolds provide 2D- and 3D-support for interaction with cells and thus convey spatial and temporal control over their function and multicellular processes, such as differentiation and morphogenesis. A model fibrillar system with tunable viscoelastic properties, comprised of 2 native ECM components like collagen type I and the GAG heparin, is presented here. Although the individual components comply with the adhesive, mechanical and bioinductive requirements for artificial reconstituted ECMs, their interaction and structural characterization remains an intriguing conundrum. The aim of the work was to analyze and structurally characterize a xenogeneic in vitro cell culture scaffold reconstituted from two native ECM components, collagen type I and the highly negatively charged glycosaminoglycan heparin. Utilizing a broad spectrum of structural analysis it could be shown that pepsin-solubilized collagen type I fibrils, reconstituted in vitro in the presence of heparin, exhibit an unusually thick and straight shape, with a non-linear dependence in size distribution, width-to-length ratio, and morphology over a wide range of GAG concentrations. The experiments imply a pronounced impact of the nucleation phase on the cofibril morphology as a result of the strong electrostatic interaction of heparin with atelocollagen. Heparin is assumed to stabilize the collagen-GAG complexes and to enhance their parallel accretion during cofibrillogenesis, furthermore corroborated by the heparin quantitation data showing the GAG to be intercalated as a linker molecule with a specific binding site inside the cofibrils. In addition, the exerted morphogenic effect of the GAG, appears to be influenced by factors as degree of sulfation, charge, and concentration. Further detailed structural analysis of the PSC-heparin gels using TEM and SFM showed a hierarchy involving 3 different structural levels and banding patterns in the system: asymmetric segment longspacing (SLS) fibrils and symmetric segments with an average periodicity (AP) of 250 - 260 nm, symmetric fibrous longspacing (FLS IV) nanofibrils with AP of 165 nm, and cofibrils exhibiting an asymmetric D-periodicity of 67 nm with a striking resemblance to the native collagen type I banding pattern. The intercalation of the high negatively charged heparin in the cofibrils was suggested as the main trigger for the hierarchical formation of the polymorphic structures. We also proposed a model explaining the unexpected presence of a symmetric and asymmetric form in the system and the principles governing the symmetric or asymmetric fate of the molecules. The last section of the experiments showed that the presence of telopeptides and heparin both had significant effects on the structural and mechanical characteristics of in vitro reconstituted fibrillar collagen type I. The implemented structural analysis showed that the presence of telopeptides in acid soluble collagen (ASC) impeded the reconstitution of D-periodic collagen fibrils in the presence of heparin, leaving behind only a symmetric polymorphic form with a repeating unit of 165 nm (FLS IV). Further x-ray diffraction analysis of both telopeptide-free and telopeptide-intact collagen fibrils showed that the absence of the flanking non-helical termini in pepsin-solubilized collagen (PSC) resulted in a less compact packing of triple helices of atelocollagen with an increase of interhelical distance from 1.0 to 1.2 nm in dried samples. The looser packing of the triple helices was accompanied by a decrease in bending stiffness of the collagen fibrils, which demonstrated that the intercalated heparin cannot compensate for the depletion of telopeptides. Based on morphological, structural and mechanical differences between ASC and PSC-heparin fibrils reported here, we endorsed the idea that heparin acts as an intrafibrillar cross-linker which competed for binding sites at places along the atelocollagen helix that are occupied in vivo by telopeptides in the fibrillar collagen type I. The performed studies are of particular interest for understanding and gaining control over a rather versatile and already exploited xenogeneic cell culture system. The reconstituted cofibrils with their unusual morphology and GAG intercalation – a phenomenon not reported in vivo – are expected to exhibit interesting biochemical behavior as a biomaterial for ECM scaffolds. Varying the experimental conditions, extent of telopeptide removal, and heparin concentration provides powerful means to control the kinetics, structure, dimensions, as well as mechanical properties of the system which is particularly important for predicting a certain cell behavior towards the newly developed matrix. The GAG intercalation could be interesting for studies with required long-term 'release upon demand' of the GAG, as well as native binding and stabilization of growth factors, cytokines, chemokines, thus providing a secondary tool to control cell signaling and fate, and later on tissue morphogenesis. / Synthetische Biomaterialien werden stetig weiterentwickelt und spielen als künstliche Mikroumgebungen eine zentrale Rolle in den modernen Strategien der regenerativen Medizin und des Tissue Engineerings. Solche sogenannten Scaffolds liefern eine 2D- und 3D-Struktur zur Interaktion mit Zellen und üben somit eine räumliche und zeitliche Kontrolle auf ihre Funktion und multizelluläre Prozesse aus, wie die Differenzierung und Morphogenese. Obwohl häufig die adhäsiven, mechanischen und bioinduzierenden Eigenschaften von Einzelkomponenten aus natürlichen Bestandteilen der extrazellulären Matrix (ECM) rekonstituierten Trägerstrukturen bekannt sind, bleiben die funktionalen und strukturellen Auswirkungen in Mehrkomponentensystemen eine faszinierende Fragestellung. Das Ziel der Arbeit war die Analyse und die strukturelle Charakterisierung einer xenogenen in vitro Zellkultur-Trägerstruktur, die aus den zwei nativen ECM Komponenten Kollagen Typ I und das stark negativ geladene Glykosaminoglykan (GAG) Heparin rekonstituiert wurde. Unter Nutzung eines breiten Spektrums von Methoden zur strukturellen Analyse konnte gezeigt werden, dass im Beisein von Heparin rekonstituierte Pepsin-gelöste Kollagen Typ I Fibrillen eine ungewöhnlich dicke und gerade Form, mit nichtlinearen Abhängigkeiten der Größenverteilung, des Breite-zu-Länge Verhältnises und der Morphologie für eine Reihe von GAG Konzentrationen, aufweisen. Die Experimente deuten auf eine besondere Wirkung der Nukleierungsphase auf die Kofibrillmorphologie hin, als Folge der starken elektrostatischen Inteaktionen Heparins mit Atelokollagen. Es wird angenommen, dass Heparin die Komplexe aus Kollagen-GAG stabilisiert, die parallele Anlagerung während der Kofibrillogenese verbessert und dass überdies, belegt durch Heparin Quantitätsdaten, als Verbindungsmolekül mit einer spezifischen Anbindungsstelle innerhalb der Kofibrillen eingelagert wird. Darüber hinaus scheint der ausgeübte morphogene Effekt des GAGs Heparins von Faktoren wie Grad der Sulfatierung, Ladung und Konzentration abzuhängen. Weitere detailierte Strukturanalysen der PSC - Heparin Gele mit TEM und SFM zeigten eine Hierarchie mit drei unterschiedlichen strukturellen Ebenen und Bandmustern im System: asymmetrisch segmentierte, weitabständige Fibrillen (SLS) und symmetrische Segmente mit einem AP von 250-260 nm, symmetrische fibrose weitabständige (FLS IV) Nanofibrillen mit einem AP von von 165 nm und Kofibrillen asymmetrischer D-Periodizität von 67 nm, die eine erstaunliche Ähnlichkeit zum natürlichen Kollagen Typ I Bandmuster haben. Die Einlagerung des sehr negativ geladenen Heparins in die Kofibrillen wurde als Hauptauslöser der hierarchischen Formation der polymorphen Strukturen betrachtet. Wir schlugen ebenso ein Model vor, welches sowohl das unerwartete Vorhandensein symmetrischer und asymmetrischer Formen im System als auch die Regeln erklärt, die das symmetrische oder asymmetrische Schicksal der Moleküle steuern. Der letzte Abschnitt der Experimente zeigte, dass die Anwesenheit der Telopeptide und Heparins eine signifikante Wirkung auf die strukturellen und mechanischen Charakteristika der in vitro rekonstituierten Kollagen Typ I Fibrillen hatte. Die durchgeführten Strukturanalysen zeigten außerdem, dass die Anwesenheit der Telopeptide in säurelöslichem Kollagen (ASC) die Rekonstitution D-periodischer Kollagenfibrillen mit Heparin verhinderte, sodass nur symmetrisch polymorphe Formen mit einer Wiederholeinheit von 165 nm möglich waren (FLS IV). Weitere Messungen der Telopeptid-freien und Telopeptid-intakten Kollagenfibrillen mit Röntgendiffraktometrie ergaben, dass die Abwesenheit der nicht-helix-strukturierten Enden in Pepsin-gelöstem Kollagen (PSC) zu einer weniger kompakten Anordnung der Tripelhelices von Atelokollagen führte. Der interhelix Abstand erhöhte sich von 1,0 zu 1,2 nm für getrocknete Proben. Das zeigt, dass die losere Anordnung der Tripelhelices einhergeht mit der Verringerung der Biege-Elastizitäts-module der Kollagenfibrillen,. Basierend auf den hier vorgestellten morphologischen, strukturellen und mechanischen Unterschieden zwischen ASC und PSC-Heparin Fibrillen wird die Idee unterstützt, dass Heparin als intrafibrillärer Vernetzer fungiert und an Bindungsstellen der Helix bindet, welche in vivo bei Kollagen Typ I Fibrillen durch Telopeptide besetzt sind. Die durchgeführten Studien sind von besonderem Interesse für das Verständnis und die Steuerung eines sehr vielseitigen und bereits verwendeten xenogenes Zellkultursystem für das Tissue Engineering. Von den rekonstituierten Kofibrillen mit ihrer ungewöhnlichen Morphologie und GAG Einlagerung - ein in vivo nicht bekanntes Phänomen - erwartet man, dass sie ein intressantes biochemisches Verhalten als Biomaterial für ECM Scaffolds zeigen. Variationen der experimentellen Bedingungen, des Ausmaßes der Telopeptidentfernung und der Heparinkonzentration liefern vielfältige Möglichkeiten um die Kinetik, Struktur, Dimension sowie die mechanischen Eigenschaften des Systems zu kontrollieren. Damit sollte es möglich sein, ein bestimmtes Zellverhalten gegenüber der neu entwickelten Matrix vorherzusagen. Die GAG-Einlagerung bietet interessante Optionen für eine langfristige Freisetzung des GAGs 'on demand', sowie die native Bindung und Stabilisierung von Wachstumsfaktoren, Cytokinen, Chemokinen, womit zusätzlich Zellsignalisierung und -schicksal und später Gewebemorphogenese kontrolliert werden kann.

Ce travail de thèse a porté sur l’étude de littoraux sous l’influence de deux grands deltas, l’Amazone et le Mékong, avec un focus sur les plages et cheniers de Guyane intégrant le système de dispersion vaseuse de l’Amazone, et sur les liens entre la déstabilisation du littoral du delta du Mékong et les changements morpho-bathymétriques des chenaux deltaïques sous influence anthropique croissante. L’étude de la plage de Montjoly en Guyane a été conduite en combinant une approche innovante de photogrammétrie aéroportée SfM (Structure from Motion), des mesures hydrodynamiques, bathymétriques, et la modélisation de la propagation des houles à travers cette bathymétrie. Les résultats obtenus montrent le potentiel considérable de la technique de photogrammétrie SfM pour l’étude géomorphologique des plages, et confirment un modèle de rotation de la plage sous l'influence de banc de vase. Le suivi du second site d’étude, un chenier en recul sur un ancien polder rizicole vaseux, au travers d'une analyse multi décennale d’images satellites et des mesures de terrain, a démontré très finement les taux (atteignant 160 m par an) et mécanismes de recul du substrat vaseux en lien avec sa rhéologie.L’analyse de l'évolution de la bathymétrie des chenaux deltaïques du Mékong sur une décennie (1998 et 2008), conduite à travers une méthode sous SIG, a permis de quantifier une perte nette de 200 millions de m3 de sédiments et un approfondissement de chenaux ne relevant pas de processus naturels mais d'extraction de granulats.Ces prélèvements importants de sédiments ont des répercussions importantes sur les apports de sédiments au littoral du delta qui montre des taux d’érosion importants. / This thesis is a geomorphic study of two separate sites associated with two large deltas: the Amazon and the Mekong, with a focus on a beach and chenier in French Guiana integrated into the mud dispersal system of the Amazon, and on the links between destabilization of the Mekong delta shoreline and morpho-bathymetric changes in the deltaic channels under increasing human influence.The study of Montjoly beach in French Guiana was carried out using a combination of an innovative approach in SfM (Structure from Motion) airborne photogrammetry, hydrodynamic and bathymetric measurements, and wave propagation modelling over the nearshore bathymetry. The results show the strong potential of SfM photogrammetry in high-resolution morphometric and sediment budget surveys of sandy beach, and confirm a previously proposed model of beach rotation under mud-bank influence.The second field site in French Guiana, a retreating chenier over a muddy abandoned polder formerly a rice fields, work based on a multi-decadal analysis of satellite images combined with short-term field topographic and hydrodynamic measurements highlighted high rates of chenier migration (up to 160 m a year) and retreat mechanisms over the muddy substrate due to its rheology.A GIS-based analysis of bathymetric changes in the deltaic channels of the Mekong over a 10-year period (1998 to 2008) enabled the quantification of a net loss of 200 million m3 of sediments and an increase in the mean depth of the channels, which appears as unnatural and due to sand mining.These important sediment extractions have serious repercussions on sediment supply to the Mekong delta coast, which shows important rates of erosion.

[pt] Alvo de intenso estudo da visão computacional, a reconstrução densa 3D teve um importante marco com os primeiros sistemas em tempo real a alcançarem precisão milimétrica com uso de câmeras RGBD e GPUs. Entretanto estes métodos não são aplicáveis a dispositivos de menor poder computacional. Tendo a limitação de recursos computacionais como requisito, o objetivo deste trabalho é apresentar um método de odometria visual utilizando câmeras comuns e sem a necessidade de GPU, baseado em técnicas de Structure from Motion (SFM) com features esparsos, utilizando as informações de uma reconstrução densa. A Odometria visual é o processo de estimar a orientação e posição de um agente (um robô, por exemplo), a partir das imagens. Esta dissertação fornece uma comparação entre a precisão da odometria calculada pelo método proposto e pela reconstrução densa utilizando o Kinect Fusion. O resultado desta pesquisa é diretamente aplicável na área de realidade aumentada, tanto pelas informações da odometria que podem ser usadas para definir a posição de uma câmera, como pela reconstrução densa, que pode tratar aspectos como oclusão dos objetos virtuais com reais. / [en] Aim of intense research in the field computational vision, dense 3D reconstruction achieves an important landmark with first methods running in real time with millimetric precision, using RGBD cameras and GPUs. However these methods are not suitable for low computational resources. Having low computational resources as requirement, the goal of this work is to show a method of visual odometry using regular cameras, without using a GPU. The proposed method is based on technics of sparse Structure From Motion (SFM), using data provided by dense 3D reconstruction. Visual odometry is the process of estimating the position and orientation of an agent (a robot, for instance), based on images. This dissertation compares the proposed method with the odometry calculated by Kinect Fusion. Results of this research are applicable in augmented reality. Odometry provided by this work can be used to model a camera and the data from dense 3D reconstruction, can be used to handle occlusion between virtual and real objects.

Das Verhalten von durch Graphen oder Graphenoxid (GO) begrenzten Molekülen hat sich, bedingt durch die bemerkenswerten strukturellen und optischen Eigenschaften dieser quasi-zweidimensionalen Materialien, als vielversprechendes Forschungsfeld erwiesen. Die vorliegende Arbeit konzentriert sich auf das Hydrationsverhalten von GO und das Verhalten kleiner, von Graphen begrenzter Moleküle. In dieser Arbeit wurde auf Rasterkraftmikroskopie (SFM) zurückgegriffen, um die GO-Hydration zu untersuchen. Die Ergebnisse zeigen ein graduelles bzw. stufenweises Ansteigen des durchschnittlichen Schichtabstands für relative Luftfeuchtigkeiten (RH) unter halb von 80%, beziehungsweise in flüssigem Wasser. Diese experimentellen Beobachtungen stimmen mit den XRD an vielschichtigem GO in der Literatur überein. Die hier gezeigten Ergebnisse lassen jedoch den angenommenen Einlagerungseffekt, bei der Hydrierung von GO bei geringer RH, außen vor. Stattdessen wird die allmähliche Ausdehnung der kontinuierlichen Einlagerung von Wassermolekülen in den einzelnen GO-Schichten zugeschrieben, während die stufenweise Ausdehnung im komplett in Wasser getauchten Zustand auf das Eindringen einer ganzen Wassermonolage zurückgeführt wird. Andererseits könnte die Grenzfläche zwischen Graphen und dem Substrat ein begrenztes elektrisches Feld aufweisen, das ein weit verbreitetes, auf Ladungstransfer an Grenzflächen zurückzuführendes Phänomen darstellt. Die vorliegende Arbeit behandelt dieses Thema unter Nutzung von Rhodamin 6G (R6G) als Molekül zwischen Graphen und Glimmer, die es begrenzen. Eine Rot-Verschiebung der R6G-Maxima bei geringer RH wird sowohl auf elektrische Felder, die sich auf die Moleküle auswirken, als auch auf mechanische Deformationen der R6G-Struktur an der Grenzschicht zurückgeführt. Die Stärke des elektrischen Feldes wird anhand des Graphen-Raman-Spektrums auf etwa 1 V/nm abgeschätzt. / The behavior of molecules confined by graphene or graphene oxide (GO) has proven to be a promising area of research owing to the remarkable structural and optical properties of these quasi two-dimensional materials. This thesis focuses on the hydration behavior of GO and the behavior of small molecules confined by graphene. In this work, scanning force microscopy (SFM) has been employed to investigate the hydration of GO. The results show a gradual and a step-like increase of the average interlayer distance for relative humidities (RH) below 80% and in liquid water, respectively. These experimental observations are consistent with XRD results on multilayered graphite oxide as reported in the literature. However, the results presented here exclude the postulated interstratification effect, for hydration of GO at low RH. Instead, the gradual expansion is attributed to the continuous incorporation of water molecules into single GO layers, while the step-like expansion when completely immersed in water, is attributed to the insertion of a full monolayer of water. On the other hand, the interface between graphene and its substrate may exhibit a confined electric field, a common phenomenon due to charge transfer at interfaces. In this work, this subject is addressed using Rhodamine 6G (R6G) as a probe molecule confined between graphene and mica. A red shift of the RG6 peaks at low RH is argued to be due to both, electric fields acting on the molecules and mechanical deformation of the R6G structure at the interface. The strength of the field is estimated from the graphene Raman spectra to be on the order of 1 V/nm.