A Model-Selection Framework for Multibody Structure-and-Motion of Image Sequences

Given an image sequence of a scene consisting of multiple rigidly moving objects, multi-body structure-and-motion (MSaM) is the task to segment the image feature tracks into the different rigid objects and compute the multiple-view geometry of each object. We present a framework for multibody structure-and-motion based on model selection. In a recover-and-select procedure, a redundant set of hypothetical scene motions is generated. Each subset of this pool of motion candidates is regarded as a possible explanation of the image feature tracks, and the most likely explanation is selected with model selection. The framework is generic and can be used with any parametric camera model, or with a combination of different models. It can deal with sets of correspondences, which change over time, and it is robust to realistic amounts of outliers. The framework is demonstrated for different camera and scene model

Geology and palaeontology of the Telychian (Silurian), reservoir formation of the North Esk inlier, near Edinburgh, Scotland

The North Esk inlier is one of several outcrops of Silurian sediments in the Midland Valley of Scotland. The lowermost sediments exposed are the Reservoir Formation, and these have been studied in detail. These sediments are interbedded shales and siltstones, deposited as the deepest part of a regressive sequence. The sediments are suggested to have been deposited predominantly by storm processes in an outer shelf or marginal basin environment, and not by turbidity currents into a deep ocean basin as previously suggested. Decreasing water depths can be traced by changes in sedimentary structures and in the animals and their bioturbation traces fossilised therein. A correspondence between the graptolites preserved in the North Esk group and models for distribution of graptolites in depth related zones is observed and is compared with other taxa thought to be indicative of water depth. Cycles of sedimentation are identified and also record fluctuations in the water depth.The NEI sediments were deposited in the remnant lapetus ocean basin at the time of a three plate collision. The sediments are currently sub-vertically oriented. Emplacement at this attitude was probably associated with thrusting at depth, in turn related to strike-slip movement o f separate terranes along the southern margin of Laurentia. Minor small scale bedding-parallel thrusts are evidence of this at the surface. The North Esk inlier sediments were probably part of a tcrranc now of unknown extent. Minor folding, local thrusting and faulting, indicating one major phase of tectonic deformation are described. Compressional kink folding took place, with pressure applied obliquely to foliation (bedding). Areas of chevron folding and kink bands correspond to deformation along Caledonian trends. The northern boundary of the NEI, previously thought to be fault controlled, is reinterpreted as the regional unconformity at the base of the Upper Old Red Sandstone. Metabentonite horizons are identified. The volcanic source of these ash falls is suggested to have been of calc-alkaline character, and an increase in alkalinity of the volcanic source in Scotland during the Telychian is suggested.A study of the fossils preserved has led to a review of late Llandovery graptolite biostratigraphy. A biozonal scheme based on that currently in use in other parts of the world, particularly in Bohemia, is introduced. Three Llandovery graptolite biozoncs arc recognised between the crenulata biozone and the base of the Wenlock. The Reservoir Formation sediments are correlated with the middle of the O. spiralis graptolite biozone, upper Telychian. Comparisons are made with the biozonal schemes for other fossil groups, and the P. celloni. to P. amorphognathoides conodont biozonc boundary is accurately identified within the Gutterford Burn sediments, facilitating accurate correlation between graptolite and conodont biozonal schemes.Revised taxonomic descriptions and notes on a number of species of graptoloid and dendroid are presented. Further work on the dendroid Dictyonema pentlandica has identified normal and abnormal dendroid growth patterns. The response of dendroids to trauma, and disease are described and possible uses of dendroids as palaeoenvironment and palaeocurrent-direction indicators are discussed. A model for the secretion of dendroid holdfasts by mobile zooids distributed across the sediment surface is suggested, and possible dendroid reproductive processes are outlined.A new technique of producing graptolite “Profile Plots” is introduced. These plots are used to identify, characterise and compare different graptoloid species, where a number of species with similar thecal structure are known. The rate of expansion of the stipe at different levels within the colony and the thecal size can be compared, and characteristic profiles plotted for each species. This technique has possible future uses in the computerised identification of graptolites

Structural lineament mapping using remote sensing in the aures massif (ne algeria)

The Aures massif is located in the eastern part of the Atlasic Domain and formed by Mesozoic and Cenozoic sedimentary rocks. The main objective of this study is to map the structural lineaments and geologically analyze their different geometric aspects, like orientation and distribution, using remote sensing data. Another important aim is to track the extent of lineaments, understand how they integrate into the regional structure and trace the main tectonic events responsible for the Aures' structuration. Both manual and automatic approaches were employed to achieve the study's objectives. More than twelve thousand lineaments were identified, and grouped into four direction families: NW-SE, NE-SW, E-W, and N-S. Two main factors control the orientation: density and distribution of the lineaments, and topographic and geologic factors. A good correspondence was found between literature and techniques employed in this work regarding structural lineament analysis showing that the Aures lineaments result from the succession of Alpine orogeny tectonic phases. Mainly two phases were responsible on its structuration: the major Atlasic event, which occurred during the Lutetitian stage with NW-SE trending, and the Alpine which happened in late Miocene with N-S compression

Two Novel Methods For The Determination Of The Number Of Components In Independent Components Analysis Models

Independent Components Analysis is a Blind Source Separation method that aims to find the pure source signals mixed together in unknown proportions in the observed signals under study. It does this by searching for factors which are mutually statistically independent. It can thus be classified among the latent-variable based methods. Like other methods based on latent variables, a careful investigation has to be carried out to find out which factors are significant and which are not. Therefore, it is important to dispose of a validation procedure to decide on the optimal number of independent components to include in the final model. This can be made complicated by the fact that two consecutive models may differ in the order and signs of similarly-indexed ICs. As well, the structure of the extracted sources can change as a function of the number of factors calculated. Two methods for determining the optimal number of ICs are proposed in this article and applied to simulated and real datasets to demonstrate their performance

Towards Zero Training for Brain-Computer Interfacing

Electroencephalogram (EEG) signals are highly subject-specific and vary considerably even between recording sessions of the same user within the same experimental paradigm. This challenges a stable operation of Brain-Computer Interface (BCI) systems. The classical approach is to train users by neurofeedback to produce fixed stereotypical patterns of brain activity. In the machine learning approach, a widely adapted method for dealing with those variances is to record a so called calibration measurement on the beginning of each session in order to optimize spatial filters and classifiers specifically for each subject and each day. This adaptation of the system to the individual brain signature of each user relieves from the need of extensive user training. In this paper we suggest a new method that overcomes the requirement of these time-consuming calibration recordings for long-term BCI users. The method takes advantage of knowledge collected in previous sessions: By a novel technique, prototypical spatial filters are determined which have better generalization properties compared to single-session filters. In particular, they can be used in follow-up sessions without the need to recalibrate the system. This way the calibration periods can be dramatically shortened or even completely omitted for these ‘experienced’ BCI users. The feasibility of our novel approach is demonstrated with a series of online BCI experiments. Although performed without any calibration measurement at all, no loss of classification performance was observed

Prospección minera de la mineralización de óxidos de Fe-Mn-Pb en Jbel Skindis (Alto Atlas Oriental, Marruecos) basada en teledetección y SIG

In recent years, remote sensing has had a prominent place in mineral exploration programs given its potential to identify alteration minerals, such as clay and hydroxyl minerals. Those minerals represent significant guides to mineral deposits considering their potential to host valuable concentrations of base metal elements. This work focuses on Fe-Mn-Pb mineral deposits within the Jbel Skindis area as a case study to illustrate the application of remote sensing images and GIS systems to highlight prospective zones and to extract information on ore-controlling factors using image enhancement and integration methods. Field observations and XRD data showed that the main remotely sensed alteration anomalies are characterized by oxides and hydroxides. Based on those indicative minerals, a mapping using Aster L1T and Landsat 8 OLI data was done: the 5/4 ratio highlighted gossans zones and the RGB combination (4/6, 2/1, 3/2) accentuates the hydrothermally altered areas. The lineament map extracted from Sentinel 2A and Landsat imagery allowed the reconstitution of the megafracture network that affected the region. The multi-criteria analysis of these satellite-derived data along with available geological data outcomes to delineate prospective zones in the study area, were found to be in highly fractured areas developing gossans and Fe rich alteration. Verified via field survey, this approach was successfully applied to the Jbel Skindis area to rapidly delineate oxidized ore outcrops. This provides a remote sensing model for future prospecting efforts for similar mineral deposits both in the Eastern High-Atlas province and in other similar areas.En los últimos años, la teledetección ha ocupado un lugar destacado en los programas de exploración minera dada su utilidad para identificar minerales de alteración, como la arcilla y los hidróxidos. Estos minerales son guías significativas para encontrar depósitos minerales que albergan concentraciones valiosas de metales base. Este trabajo se centra en las mineralizaciones de Fe-Mn-Pb dentro del área de Jbel Skindis consideradas como un zona de estudio para ilustrar la aplicación de imágenes de teledetección y de un sistema SIG para delinear zonas de interés para la exploración minera y extraer información sobre los factores que controlan las concentraciones de metales utilizando tratamiento de datos satélites e integración de imágenes. De acuerdo con las observaciones de campo y los datos DRX las principales anomalías de alteración deducidas del tratamiento de datos satélite se caracterizan por óxidos e hidróxidos. En base a estos minerales, se realizó un mapeo utilizando los datos de Aster L1T y Landsat 8 OLI: la relación 5/4 resalta las zonas de Gossans mientras la combinación RGB (4/6, 2/1, 3/2) señala las áreas alteradas. El mapa de lineamientos extraído de las imágenes de Sentinel 2A y Landsat permitió reconstituir la red de megafracturas que afectó a la región. El acoplamiento entre un análisis multi-criterio de los datos derivados de satélites y los datos geológicos disponibles, permitió delinear zonas de interés para la exploración minera en el área de estudio. Estas zonas corresponden a áreas altamente fracturadas en las cuales se desarrollan gossans y alteración rica en Fe. Este enfoque junto con un control a través de un estudio de campo, se aplicó con éxito en el área de Jbel Skindis para delinear rápidamente los afloramientos de mineralizaciones oxidadas. Esto proporciona un modelo de teledetección para futuros esfuerzos de prospección de depósitos minerales similares tanto en la provincia oriental del Alto Atlas como en otras áreas similares

Logan Medallist 2. Geophysics and Geology: An Essential Combination Illustrated by LITHOPROBE Interpretations–Part 1, Lithospheric Examples

Lithoprobe (1984–2005), Canada’s national, collaborative, multidisciplinary, Earth science research project, investigated the structure and evolution of the Canadian landmass and its margins. It was a highly successful project that redefined the nature of Earth science research in Canada. One of many contributions deriving from the project was the demonstration by example that Earth scientists from geophysics and geology, including all applicable sub-disciplines within these general study areas, must work together to achieve thorough and comprehensive interpretations of all available data sets. In this article, I exemplify such contributions by summarizing interpretations of lithospheric structure and development from Lithoprobe journal publications relating to eleven specific regions in Canada. Four of the examples derive from studies in the Mesozoic–Cenozoic Canadian Cordillera: the original Lithoprobe program on Vancouver Island, the region of the Monashee Mountains in the southeastern Cordillera, allochthonous and autochthonous terranes in the northwestern Cordillera, and the craton-Cordillera transition in northeastern British Columbia. Two examples represent the Paleozoic Appalachians in Newfoundland. One of these shows crustal structure across the southwestern part of the island; the other shows a more detailed study on the southwestern coast. The Mesoproterozoic Grenville Province is the focus of two examples. One shows crustal structure from the Archean Pontiac metasedimentary sub-province across the Grenville Front and the exposed southeastern part of the province; the other illustrates two- and three-dimensional interpretation in the central Grenville Province. Lithoprobe supported research in the development of geodynamical modelling techniques and the application of these to tectonic processes inferred within transect study areas. Such work is exemplified through a comparison of a numerical model developed for the southwestern Grenville orogen and comparison of model results with those from geophysical and geological studies. Lithoprobe carried out extensive research in the Paleoproterozoic Trans-Hudson Orogen in Saskatchewan and Manitoba. Some early results from the interpreted seismic results completely revised previous results based on geology only and fostered additional geological studies. This is illustrated by studies over an Archean window in the middle of the orogen. The final example derives from studies in the westernmost part of the Archean Superior Province in western Ontario. It focuses on the derivation of near-surface velocity information from the seismic reflection data and the relationship of this information to the known geology.SOMMAIRELithoprobe (1984–2005) est ce projet de recherche national canadien,  multidisciplinaire et coopératif en science de la Terre, qui a étudié la structure, l'évolution et les marges de la masse continentale du Canada.  Ce fut un projet très réussi qui a redéfini la nature de la recherche en sciences de la Terre au Canada. L'une des nombreuses répercussions de ce projet a été la démonstration que les scientifiques de la Terre en géophysique et en géologie, y compris tous les sous-disciplines applicables de ces domaines d'études générales, doivent collaborer pour espérer obtenir des interprétations rigoureuses et exhaustives de tous les ensembles de données disponibles. Dans cet article, j’illustre des contributions de ce genre en résumant les interprétations structurales et l’évolution de la lithosphère à partir des publications de Lithoprobe dans des revues portant sur onze régions définies du Canada. Quatre des exemples proviennent d’études du Mésozoïque-Cénozoïque dans la Cordillère canadienne : le programme Lithoprobe d'origine sur l'île de Vancouver, la région des montagnes Monashee dans le sud-est de la Cordillère, les terranes allochtones et autochtones dans le nord-ouest de la Cordillère, et la transition du craton à la Cordillère nord-est de la Colombie-Britannique. Deux exemples représentent le Paléozoïque des Appalaches à Terre-Neuve. L'un de ces exemples révèle l’existence d’une structure crustale dans la partie sud-ouest de l'île; l'autre est une étude plus détaillée de la portion sud-ouest de la côte. Le Mésoprotérozoïque de la Province de Grenville est l'objet de deux exemples. Un exemple révèle la structure de la croûte de la sous-province archéenne de roches métasédimentaires Pontiac à travers le front de Grenville et la partie sud-est de la Province qui affleure; l'autre est une interprétation en deux et trois dimensions de la portion centrale de la Province de Grenville. Lithoprobe a favorisé la recherche de mise au point de techniques de modélisation géodynamique et l'application de celles-ci à des processus tectoniques présumés dans les zones d'étude de transects. Ce travail est illustré par une comparaison d'un modèle numérique développé pour la portion sud-ouest de l'orogène de Grenville et la comparaison des résultats du modèle avec ceux des études géophysiques et géologiques. Lithoprobe a réalisé des recherches approfondies de l’orogène trans-hudsonien en Saskatchewan et au Manitoba. Certains des premiers résultats basés sur l’interprétation des données sismiques ont complètement remis en question les résultats précédents basés sur la géologie seulement, et justifié des études géologiques supplémentaires. Ceci est illustré par des études sur une fenêtre archéenne au milieu de l'orogène. Le dernier exemple provient d'études réalisées dans la partie la plus à l’ouest de la Province du Supérieur archéenne de l'ouest de l'Ontario. Il porte sur des informations déduites des vitesses sismiques de faibles profondeurs sur des données de sismique réflexion et de la relation de ces informations avec la géologie connue

The Mode and Timing of Microplate Docking along the Highland Boundary Fault Zone, Scotland

The Highland Boundary Fault Zone is a major crustal fracture with a long and complex structural history, in which brittle deformation was superimposed upon pre-existing fabrics produced by ductile deformation. This thesis describes and interprets the history of HBFZ tectonism, presented in reverse chronological order (youngest events first). Although the HBFZ still experiences small-scale earthquakes, there is evidence to show that significant fault displacement has not occurred since the end of the Carboniferous. Extensional deformation during the Upper Devonian and the Carboniferous was small-scale and localised. Upper crustal deformation in mid-Devonian times, possibly caused by the accretion of the Avalonian terrane with Laurentia, was low in magnitude but widespread in aerial extent. The results and interpretations of a mesofracture analysis are presented to help constrain mid-Devonian brittle deformation across central Scotland. The results show that regional north-south compression caused transpressional reactivation of the pre-existing HBFZ. Because our existing understanding of transpression is incapable of explaining the results of the mesofracture analysis, an alternative transpression model is proposed, in which transpressive strain is "partitioned" into two components; a strike-slip component restricted to the fault zone, and a thrust component deforming the rocks that flank the zone. The "strain-partitioning" model, with some elaboration, helps to explain the mid-Devonian deformation seen in central Scotland. The balance of evidence from the Highland Border, Dalradian, and Midland Valley terranes suggests that ductile deformation along the HBFZ occurred in response to terrane accretion, which probably took place in Ordovician times. A palaeo-tectonic model is presented in which Highland Border and Midland Valley terranes were accreted and laterally displaced, with a sinistrally transpressive sense, onto the Laurentian margin in the Llandeilo and/or Caradoc, and again in the Ashgill and/or Llandovery. The extreme difficulties of postulating the palaeo-tectonic histories of disrupted terranes are discussed in detail

Scalable Tools for Information Extraction and Causal Modeling of Neural Data

Systems neuroscience has entered in the past 20 years into an era that one might call "large scale systems neuroscience". From tuning curves and single neuron recordings there has been a conceptual shift towards a more holistic understanding of how the neural circuits work and as a result how their representations produce neural tunings. With the introduction of a plethora of datasets in various scales, modalities, animals, and systems; we as a community have witnessed invaluable insights that can be gained from the collective view of a neural circuit which was not possible with small scale experimentation. The concurrency of the advances in neural recordings such as the production of wide field imaging technologies and neuropixels with the developments in statistical machine learning and specifically deep learning has brought system neuroscience one step closer to data science. With this abundance of data, the need for developing computational models has become crucial. We need to make sense of the data, and thus we need to build models that are constrained up to the acceptable amount of biological detail and probe those models in search of neural mechanisms. This thesis consists of sections covering a wide range of ideas from computer vision, statistics, machine learning, and dynamical systems. But all of these ideas share a common purpose, which is to help automate neuroscientific experimentation process in different levels. In chapters 1, 2, and 3, I develop tools that automate the process of extracting useful information from raw neuroscience data in the model organism C. elegans. The goal of this is to avoid manual labor and pave the way for high throughput data collection aiming at better quantification of variability across the population of worms. Due to its high level of structural and functional stereotypy, and its relative simplicity, the nematode C. elegans has been an attractive model organism for systems and developmental research. With 383 neurons in males and 302 neurons in hermaphrodites, the positions and function of neurons is remarkably conserved across individuals. Furthermore, C. elegans remains the only organism for which a complete cellular, lineage, and anatomical map of the entire nervous system has been described for both sexes. Here, I describe the analysis pipeline that we developed for the recently proposed NeuroPAL technique in C. elegans. Our proposed pipeline consists of atlas building (chapter 1), registration, segmentation, neural tracking (chapter 2), and signal extraction (chapter 3). I emphasize that categorizing the analysis techniques as a pipeline consisting of the above steps is general and can be applied to virtually every single animal model and emerging imaging modality. I use the language of probabilistic generative modeling and graphical models to communicate the ideas in a rigorous form, therefore some familiarity with those concepts could help the reader navigate through the chapters of this thesis more easily. In chapters 4 and 5 I build models that aim to automate hypothesis testing and causal interrogation of neural circuits. The notion of functional connectivity (FC) has been instrumental in our understanding of how information propagates in a neural circuit. However, an important limitation is that current techniques do not dissociate between causal connections and purely functional connections with no mechanistic correspondence. I start chapter 4 by introducing causal inference as a unifying language for the following chapters. In chapter 4 I define the notion of interventional connectivity (IC) as a way to summarize the effect of stimulation in a neural circuit providing a more mechanistic description of the information flow. I then investigate which functional connectivity metrics are best predictive of IC in simulations and real data. Following this framework, I discuss how stimulations and interventions can be used to improve fitting and generalization properties of time series models. Building on the literature of model identification and active causal discovery I develop a switching time series model and a method for finding stimulation patterns that help the model to generalize to the vicinity of the observed neural trajectories. Finally in chapter 5 I develop a new FC metric that separates the transferred information from one variable to the other into unique and synergistic sources. In all projects, I have abstracted out concepts that are specific to the datasets at hand and developed the methods in the most general form. This makes the presented methods applicable to a broad range of datasets, potentially leading to new findings. In addition, all projects are accompanied with extensible and documented code packages, allowing theorists to repurpose the modules for novel applications and experimentalists to run analysis on their datasets efficiently and scalably. In summary my main contribution in this thesis are the following: 1) Building the first atlases of hermaphrodite and male C. elegans and developing a generic statistical framework for constructing atlases for a broad range of datasets. 2) Developing a semi-automated analysis pipeline for neural registration, segmentation, and tracking in C. elegans. 3) Extending the framework of non-negative matrix factorization to datasets with deformable motion and developing algorithms for joint tracking and signal demixing from videos of semi-immobilized C. elegans. 4) Defining the notion of interventional connectivity (IC) as a way to summarize the effect of stimulation in a neural circuit and investigating which functional connectivity metrics are best predictive of IC in simulations and real data. 5) Developing a switching time series model and a method for finding stimulation patterns that help the model to generalize to the vicinity of the observed neural trajectories. 6) Developing a new functional connectivity metric that separates the transferred information from one variable to the other into unique and synergistic sources. 7) Implementing extensible, well documented, open source code packages for each of the above contributions

On the use of smartphones as novel photogrammetric water gauging instruments: Developing tools for crowdsourcing water levels

The term global climate change is omnipresent since the beginning of the last decade. Changes in the global climate are associated with an increase in heavy rainfalls that can cause nearly unpredictable flash floods. Consequently, spatio-temporally high-resolution monitoring of rivers becomes increasingly important. Water gauging stations continuously and precisely measure water levels. However, they are rather expensive in purchase and maintenance and are preferably installed at water bodies relevant for water management. Small-scale catchments remain often ungauged. In order to increase the data density of hydrometric monitoring networks and thus to improve the prediction quality of flood events, new, flexible and cost-effective water level measurement technologies are required. They should be oriented towards the accuracy requirements of conventional measurement systems and facilitate the observation of water levels at virtually any time, even at the smallest rivers. A possible solution is the development of a photogrammetric smartphone application (app) for crowdsourcing water levels, which merely requires voluntary users to take pictures of a river section to determine the water level. Today’s smartphones integrate high-resolution cameras, a variety of sensors, powerful processors, and mass storage. However, they are designed for the mass market and use low-cost hardware that cannot comply with the quality of geodetic measurement technology. In order to investigate the potential for mobile measurement applications, research was conducted on the smartphone as a photogrammetric measurement instrument as part of the doctoral project. The studies deal with the geometric stability of smartphone cameras regarding device-internal temperature changes and with the accuracy potential of rotation parameters measured with smartphone sensors. The results show a high, temperature-related variability of the interior orientation parameters, which is why the calibration of the camera should be carried out during the immediate measurement. The results of the sensor investigations show considerable inaccuracies when measuring rotation parameters, especially the compass angle (errors up to 90° were observed). The same applies to position parameters measured by global navigation satellite system (GNSS) receivers built into smartphones. According to the literature, positional accuracies of about 5 m are possible in best conditions. Otherwise, errors of several 10 m are to be expected. As a result, direct georeferencing of image measurements using current smartphone technology should be discouraged. In consideration of the results, the water gauging app Open Water Levels (OWL) was developed, whose methodological development and implementation constituted the core of the thesis project. OWL enables the flexible measurement of water levels via crowdsourcing without requiring additional equipment or being limited to specific river sections. Data acquisition and processing take place directly in the field, so that the water level information is immediately available. In practice, the user captures a short time-lapse sequence of a river bank with OWL, which is used to calculate a spatio-temporal texture that enables the detection of the water line. In order to translate the image measurement into 3D object space, a synthetic, photo-realistic image of the situation is created from existing 3D data of the river section to be investigated. Necessary approximations of the image orientation parameters are measured by smartphone sensors and GNSS. The assignment of camera image and synthetic image allows for the determination of the interior and exterior orientation parameters by means of space resection and finally the transfer of the image-measured 2D water line into the 3D object space to derive the prevalent water level in the reference system of the 3D data. In comparison with conventionally measured water levels, OWL reveals an accuracy potential of 2 cm on average, provided that synthetic image and camera image exhibit consistent image contents and that the water line can be reliably detected. In the present dissertation, related geometric and radiometric problems are comprehensively discussed. Furthermore, possible solutions, based on advancing developments in smartphone technology and image processing as well as the increasing availability of 3D reference data, are presented in the synthesis of the work. The app Open Water Levels, which is currently available as a beta version and has been tested on selected devices, provides a basis, which, with continuous further development, aims to achieve a final release for crowdsourcing water levels towards the establishment of new and the expansion of existing monitoring networks.Der Begriff des globalen Klimawandels ist seit Beginn des letzten Jahrzehnts allgegenwärtig. Die Veränderung des Weltklimas ist mit einer Zunahme von Starkregenereignissen verbunden, die nahezu unvorhersehbare Sturzfluten verursachen können. Folglich gewinnt die raumzeitlich hochaufgelöste Überwachung von Fließgewässern zunehmend an Bedeutung. Pegelmessstationen erfassen kontinuierlich und präzise Wasserstände, sind jedoch in Anschaffung und Wartung sehr teuer und werden vorzugsweise an wasserwirtschaftlich-relevanten Gewässern installiert. Kleinere Gewässer bleiben häufig unbeobachtet. Um die Datendichte hydrometrischer Messnetze zu erhöhen und somit die Vorhersagequalität von Hochwasserereignissen zu verbessern, sind neue, kostengünstige und flexibel einsetzbare Wasserstandsmesstechnologien erforderlich. Diese sollten sich an den Genauigkeitsanforderungen konventioneller Messsysteme orientieren und die Beobachtung von Wasserständen zu praktisch jedem Zeitpunkt, selbst an den kleinsten Flüssen, ermöglichen. Ein Lösungsvorschlag ist die Entwicklung einer photogrammetrischen Smartphone-Anwendung (App) zum Crowdsourcing von Wasserständen mit welcher freiwillige Nutzer lediglich Bilder eines Flussabschnitts aufnehmen müssen, um daraus den Wasserstand zu bestimmen. Heutige Smartphones integrieren hochauflösende Kameras, eine Vielzahl von Sensoren, leistungsfähige Prozessoren und Massenspeicher. Sie sind jedoch für den Massenmarkt konzipiert und verwenden kostengünstige Hardware, die nicht der Qualität geodätischer Messtechnik entsprechen kann. Um das Einsatzpotential in mobilen Messanwendungen zu eruieren, sind Untersuchungen zum Smartphone als photogrammetrisches Messinstrument im Rahmen des Promotionsprojekts durchgeführt worden. Die Studien befassen sich mit der geometrischen Stabilität von Smartphone-Kameras bezüglich geräteinterner Temperaturänderungen und mit dem Genauigkeitspotential von mit Smartphone-Sensoren gemessenen Rotationsparametern. Die Ergebnisse zeigen eine starke, temperaturbedingte Variabilität der inneren Orientierungsparameter, weshalb die Kalibrierung der Kamera zum unmittelbaren Messzeitpunkt erfolgen sollte. Die Ergebnisse der Sensoruntersuchungen zeigen große Ungenauigkeiten bei der Messung der Rotationsparameter, insbesondere des Kompasswinkels (Fehler von bis zu 90° festgestellt). Selbiges gilt auch für Positionsparameter, gemessen durch in Smartphones eingebaute Empfänger für Signale globaler Navigationssatellitensysteme (GNSS). Wie aus der Literatur zu entnehmen ist, lassen sich unter besten Bedingungen Lagegenauigkeiten von etwa 5 m erreichen. Abseits davon sind Fehler von mehreren 10 m zu erwarten. Infolgedessen ist von einer direkten Georeferenzierung von Bildmessungen mittels aktueller Smartphone-Technologie abzusehen. Unter Berücksichtigung der gewonnenen Erkenntnisse wurde die Pegel-App Open Water Levels (OWL) entwickelt, deren methodische Entwicklung und Implementierung den Kern der Arbeit bildete. OWL ermöglicht die flexible Messung von Wasserständen via Crowdsourcing, ohne dabei zusätzliche Ausrüstung zu verlangen oder auf spezifische Flussabschnitte beschränkt zu sein. Datenaufnahme und Verarbeitung erfolgen direkt im Feld, so dass die Pegelinformationen sofort verfügbar sind. Praktisch nimmt der Anwender mit OWL eine kurze Zeitraffersequenz eines Flussufers auf, die zur Berechnung einer Raum-Zeit-Textur dient und die Erkennung der Wasserlinie ermöglicht. Zur Übersetzung der Bildmessung in den 3D-Objektraum wird aus vorhandenen 3D-Daten des zu untersuchenden Flussabschnittes ein synthetisches, photorealistisches Abbild der Aufnahmesituation erstellt. Erforderliche Näherungen der Bildorientierungsparameter werden von Smartphone-Sensoren und GNSS gemessen. Die Zuordnung von Kamerabild und synthetischem Bild erlaubt die Bestimmung der inneren und äußeren Orientierungsparameter mittels räumlichen Rückwärtsschnitt. Nach Rekonstruktion der Aufnahmesituation lässt sich die im Bild gemessene 2D-Wasserlinie in den 3D-Objektraum projizieren und der vorherrschende Wasserstand im Referenzsystem der 3D-Daten ableiten. Im Soll-Ist-Vergleich mit konventionell gemessenen Pegeldaten zeigt OWL ein erreichbares Genauigkeitspotential von durchschnittlich 2 cm, insofern synthetisches und reales Kamerabild einen möglichst konsistenten Bildinhalt aufweisen und die Wasserlinie zuverlässig detektiert werden kann. In der vorliegenden Dissertation werden damit verbundene geometrische und radiometrische Probleme ausführlich diskutiert sowie Lösungsansätze, auf der Basis fortschreitender Entwicklungen von Smartphone-Technologie und Bildverarbeitung sowie der zunehmenden Verfügbarkeit von 3D-Referenzdaten, in der Synthese der Arbeit vorgestellt. Mit der gegenwärtig als Betaversion vorliegenden und auf ausgewählten Geräten getesteten App Open Water Levels wurde eine Basis geschaffen, die mit kontinuierlicher Weiterentwicklung eine finale Freigabe für das Crowdsourcing von Wasserständen und damit den Aufbau neuer und die Erweiterung bestehender Monitoring-Netzwerke anstrebt