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.

Vainikinių arterijų tyrimas daugiapjūviu kompiuteriniu tomografu (DKT) į klinikinę praktiką įdiegtas nesenai. Tai neinvazyvus tyrimo metodas, kurį galima atlikti ir ambulatoriniams pacientams. Tačiau greta savo privulumų, jis turi ir trūkumų – dėl nuolatinio vainikinių arterijų judėjimo širdies ciklo metu gali atsirasti liekamųjų judesio artefaktų atkuriant vaizdus. Jų tikimybė priklauso ne tik nuo aparato, kuriuo atliekamas tyrimas, techninių charakteristikų, bet ir nuo širdies veiklos ypatumų. Yra atlikta nemažai tyrimų, įvertinančių vainikinių arterijų vaizdų kokybės priklausomybę nuo širdies susitraukimų dažnio, jo variabilumo, kitų faktorių. Kairiosios Hiso pluošto kojytės blokados, sąlygojančios nesinchronišką skilvelių susitraukimą ir atsipalaidavimą, įtaka vaizdų kokybei tyrinėta mažai. Šiame tyrime buvo palyginta vaizdų kokybė tarp pacientų, kuriems nustatyta visiška kairiosios Hiso pluošto kojytės blokada ir nėra laidžiosios sistemos sutrikimų, grupių. Analizuota vainikinių arterijų įvertinimo visuose širdies ciklo rekonstrukciniuose intervaluose įtaka vaizdų kokybės vidurkiui. Nustatyta, kokia yra DKT tyrimo diagnostinė vertė identifikuojant hemodinamiškai reikšmingas vainikinių arterijų stenozes. Kadangi DKT tyrimas susijęs su jonizuojančia spinduliuote, įvertinti rentgeno vamzdžio srovės stiprumo moduliavimo ypatumai. Taip pat nustatyta širdies susitraukimų dažnio, jo variabilumo įtaka vaizdų kokybei, esant visiškai kairiosios Hiso pluošto kojytės blokadai. / Multislice computed tomography (MSCT) coronary angiography is one of the latest usage area of the computed tomography technology. It s a non-invasive diagnostic tool, wich can be performed in ambulant patients. MSCT coronary angiography beside it's advantages has some drawbacks. The main drawbacks are lower spatial resolution and residual motion artifacts in MSCT images. Therefore quality of coronary images and diagnostic value of MSCT angiography differs, depending on patient's clinical characteristics, especially on heart contraction features during scanning. Asynchronic contraction and relaxation of the right and left ventricles, caused of bundle branch block can also influence image quality of MSCT coronary angiography. To date, there are only few studies, conducted to analyse diagnostic performance of MSCT coronary angiography in patients with left bundle branch block. Although influence of heart rate, heart rate variability and the other factors (for example, age, sex, body mass index) on MSCT image quality are quite well investigated. Thus, the present study were designed to investigate the influence of complete left bundle branch block on image quality of MSCT coronary angiography more detail in comparison with control patients group without electrical conduction disturbances, reveal the diagnostic value of MSCT angiography to identify hemodinamicaly significant coronary stenosis.

Rotator cuff pathologies involving supraspinatus are a common cause of musculoskeletal morbidity and can lead to significant disability affecting the overall quality of life. Architectural parameters of the muscle directly influence its functional properties. Therefore, understanding of fiber bundle changes with surgery and different exercises can assist clinicians in planning better surgical and shoulder rehabilitative protocols. The first objective of this thesis was to systematically review human cadaveric studies of the normal supraspinatus architecture and highlight the key aspects that should be considered while performing studies of skeletal muscle architecture. The second objective was to understand the impact of surgical repair on the structural and functional recovery of the supraspinatus. The final objective was to provide a scientific rationale behind choosing an exercise to strengthen supraspinatus by investigating its muscle architecture. Study 1 systematically reviewed human cadaveric studies of the normal supraspinatus architecture. Results showed that the overall quality of majority of included is poor and there was a large range in the reported architectural values of the entire muscle. In conclusion, there were only a few studies providing the level of detail and quality suitable for advancing our understanding of shoulder biomechanics. Study 2 quantified and compared the fiber bundle architecture of the pathologic supraspinatus pre- and post-operatively at multiple time points. Results showed significant lengthening of fiber bundles after one month of surgery which then decreased significantly by 6 months of surgery. In contrast, an initial decrease followed by an increase in pennation angle overtime was found. The results suggest that the stretching applied to the tendon and muscle during repair could affect the length-tension relationship of the muscle, which in turn can compromise its function and may lead to inferior surgical outcomes. Study 3 compared the efficacy of three commonly prescribed supraspinatus strengthening exercises in the rehabilitation setting based on the architectural changes following resistance training. Results showed there was no change in FBL and increased strength after resistance training with prone horizontal abduction exercise. Findings suggest that prone horizontal abduction may be a more suitable exercise to strengthen supraspinatus.

One of the primary concerns associated with timber harvesting is the production of sediments from stream crossings. While research has shown that using improved haul road crossings can mitigate sediment production in perennial streams compared to the use of unimproved crossings little research has been undertaken on temporary skidder crossings of headwater streams, a situation common to a significant percentage of ground skidding operations. This experiment consisted of a controlled replicated testing of the effectiveness of four types of temporary skidder stream crossings (unimproved ford, corrugated culvert, wood panel skidder bridge, and PVC pipe bundle) relative to bedload and suspended sediment production. Automated samplers were used to monitor sediment and bedload production during the construction, use, removal, and post-removal phases associated with the use of these temporary crossings. Results showed that elevated crossings mitigated total sediment production compared to unimproved fords. Further, wood panel bridges yielded lower amounts of sediment than culverts but PVC pipe bundles show no difference between bridges or culverts. Sediment production varied by crossing type and use phase. While no differences were found among crossings types during construction, there was a difference between improved crossings and fords during use. Further, bridges and PVC pipe bundle crossings produced significantly less sediments than culverts during both their removal and during post-removal sampling and fords produced the largest amount of sediments during these phases.

On the tangent bundle of a Riemannian manifold the most natural choice of metric tensor field is the Sasaki metric. This immediately brings up the question of infinitesimal symmetries associated with the inherent geometry of the tangent bundle arising from the Sasaki metric. The elucidation of the form and the classification of the Killing vector fields have already been effected by the Japanese school of Riemannian geometry in the sixties. In this thesis we shall take up the conformal vector fields of the Sasaki metric with the help of relatively advanced techniques.

Made available in DSpace on 2014-06-11T19:26:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-18Bitstream added on 2014-06-13T20:08:05Z : No. of bitstreams: 1 galao_ph_me_sjrp.pdf: 533527 bytes, checksum: e6eea706db9ff1f10f8ba9df3a1fdea7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho tem como objetivo principal o cálculo do grupo de homotopia de alguns grupos clássicos, como o grupo das rotações do espaço Euclidiano Rn, SO(n), o grupo unitário U(n), seu subgrupo especial unitário SU(n) e o grupo simpléetico Sp(n). Para esses cálculos usaremos seqüências exatas e propriedades relacionadas à fibrados. / The main purpose of this work is to calculate homotopy groups of some classical groups as the rotation groups of the euclidean space Rn, SO(n), the unitary group U(n), your special unitary subgroup SU(n) and the symplectic group Sp(n). For these calculus we will use exact sequences and properties relacionated to the fibre bundle. Keywords: Exact Sequences, Fibre Bundle, Classical Groups, Homotopy Groups.

Made available in DSpace on 2015-05-15T11:46:09Z (GMT). No. of bitstreams: 1 ArquivoTotalOsvaldo.pdf: 1490620 bytes, checksum: 022e9b1169cd35f90c2e82c9ae74fe26 (MD5) Previous issue date: 2008-12-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / We present the own mathematic formalism to, first of all, study the holonomy interpretations of the adiabatic geometric phase presented by Berry-Simon and Aharanov-Anadan and, after this, the similirities found with the theory of representation groups, particularly, with the Borel-Weil-Bott theorem. These relations are made through classification of complex bundle line, and these results are used to introduce a cranked Hamiltonian. In general, we also show that the parameter space is a flag manifold or a submanifold of her and present a topologic argument of this space that indicates the relation between the structure Riemannian and the Berry s connection. / Apresentamos o formalismo matemático próprio para, primeiramente, estudarmos as interpretações holonômicas da fase geométrica adiabática apresentadas por Berry-Simon e Aharanov-Anadan e, em seguida, as similaridades encontradas com a Teoria de Representações de Grupos, em particular, com o teorema de Borel-Weil-Bott. Estas relações são feitas via classificação de fibrados linha complexos, e esses resultados são usados para introduzir um procedimento que trata a não-adiabaticidade e a adiabaticidade da fase de Berry por meio de uma modificação na hamiltoniana. Mostramos, também, que em geral, o espaço de parâmetros é uma variedade de bandeira ou uma subvariedade dela e apresentamos um argumento topológico desse espaço, que indica a relação entre a estrutura Riemanniana e a conexão de Berry.

Made available in DSpace on 2015-05-15T11:46:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 578974 bytes, checksum: e512f47deae8cd03667ae8e7c2143b34 (MD5) Previous issue date: 2013-05-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The notions of connection and covariant derivative has its origin in the field of Riemannian geometry , where there is no distinction between them. In fact, in this study we found that these notions are equivalent if we consider modules over K-algebras of finite type. We also show that the existence of connections implies the existence of covariant derivative. The main goal of this study is to determine which modules admit connections. We easily verified that the projective modules admit connections. In fact, they form an affine space. But we also display a module that is not projective and has connection. Later, inspired by Swan's theorem, we explore in a straightforward way modules formed by sections of the tangent bundle of some surfaces in 3-dimensional real space. Finally, we study the notion of connection introduced by Alain Connes in modules over K-algebras not necessarily commutative. And we find in that context that the modules that have connection are exactly the projectives modules. / As noções de conexão e derivada covariante tem sua origem na área de geometria riemanniana, onde não existe distinção entre elas. De fato, nós verificamos neste trabalho, que estas noções são equivalentes se considerarmos módulos sobre K-álgebras comutativas de tipo finito. Também mostramos que a existência de conexões implica na existência de derivada covariante. O objetivo central deste trabalho é determinar que módulos admitem conexão. Verificamos facilmente que os módulos projetivos admitem conexões. De fato, elas formam um espaço afim. Mas também exibimos um módulo não projetivo que possui conexão. Posteriormente, inspirados pelo teorema de Swan, exploramos de maneira direta os módulos formados pelas seções do fibrado tangente de algumas superfícies no espaço 3- dimensional real. Por fim, estudamos a noção de conexão introduzida por Alain Connes em módulos sobre K-álgebras não necessariamente comutativas. E verificamos nesse contexto que os módulo que admitem conexão são exatamente os módulos projetivos.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-29T14:33:20Z No. of bitstreams: 1 williamfredericovasconcellossilva.pdf: 451866 bytes, checksum: bfeb4aa8aa637b66cf493889e77ebca1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-29T19:47:08Z (GMT) No. of bitstreams: 1 williamfredericovasconcellossilva.pdf: 451866 bytes, checksum: bfeb4aa8aa637b66cf493889e77ebca1 (MD5) / Made available in DSpace on 2017-05-29T19:47:08Z (GMT). No. of bitstreams: 1 williamfredericovasconcellossilva.pdf: 451866 bytes, checksum: bfeb4aa8aa637b66cf493889e77ebca1 (MD5) Previous issue date: 2012-07-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O principal objetivo do trabalho é estudar a relação entre o espaço de Moduli de feixes de quádricas em Pn e o espaço de Moduli de formas binárias de grau (n + 1). Este estudo foi baseado no artigo (AVRITZER; LANGE, 2000). Em linhas gerais, um espaço de Moduli é uma variedade algébrica que parametriza uma coleção de objetos C, módulo uma relação de equivalência. No nosso caso, C é o conjunto de feixes de quádricas em Pn ou o conjunto de formas binárias de grau (n + 1), e a relação de equivalência é pertencer à mesma órbita pela ação de um grupo G. Para estabelecermos a relação entre esses espaços foi importante considerar o símbolo de Segre que é um invariante dos feixes de quádricas. Além disso, estudamos a forma normal, uma maneira de reescrever o feixe de quádricas, na qual conhecemos facilmente o símbolo de Segre. Estudamos ação de grupos, para podermos classificar um feixe de quádrica e uma forma binária como estável, semi-estável ou instável, e quociente categórico, já que os espaços de Moduli são obtidos através do quociente. / The main objective is to study the relationship between space Moduli of pencil of quadrics, and Moduli space of binary forms. This study was based on article (AVRITZER; LANGE, 2000). In general, a Moduli space is an algebraic variety that parametrizes a collection of objects C, modulo an equivalence relation. In our case, C is the set of pencil of quadrics or set of binary forms of degree (n + 1), and the equivalence relation is to belong to the same orbit by the action of a group G. To establish the relationship between these spaces is important to consider the Segre symbol of which is an invariant of pencils of quadrics. Furthermore, we studied the normal form, a way to rewrite the pencil of quadrics, which easily met the Segre symbol, action of groups, in order to classify a pencil of quadric and a binary form as stable or semistable unstable, and quotient categorical, since the spaces's moduli are obtained by quotient.

Abstract : Images acquired from unmanned aerial vehicles (UAVs) can provide data with unprecedented spatial and temporal resolution for three-dimensional (3D) modeling. Solutions developed for this purpose are mainly operating based on photogrammetry concepts, namely UAV-Photogrammetry Systems (UAV-PS). Such systems are used in applications where both geospatial and visual information of the environment is required. These applications include, but are not limited to, natural resource management such as precision agriculture, military and police-related services such as traffic-law enforcement, precision engineering such as infrastructure inspection, and health services such as epidemic emergency management. UAV-photogrammetry systems can be differentiated based on their spatial characteristics in terms of accuracy and resolution. That is some applications, such as precision engineering, require high-resolution and high-accuracy information of the environment (e.g. 3D modeling with less than one centimeter accuracy and resolution). In other applications, lower levels of accuracy might be sufficient, (e.g. wildlife management needing few decimeters of resolution). However, even in those applications, the specific characteristics of UAV-PSs should be well considered in the steps of both system development and application in order to yield satisfying results. In this regard, this thesis presents a comprehensive review of the applications of unmanned aerial imagery, where the objective was to determine the challenges that remote-sensing applications of UAV systems currently face. This review also allowed recognizing the specific characteristics and requirements of UAV-PSs, which are mostly ignored or not thoroughly assessed in recent studies. Accordingly, the focus of the first part of this thesis is on exploring the methodological and experimental aspects of implementing a UAV-PS. The developed system was extensively evaluated for precise modeling of an open-pit gravel mine and performing volumetric-change measurements. This application was selected for two main reasons. Firstly, this case study provided a challenging environment for 3D modeling, in terms of scale changes, terrain relief variations as well as structure and texture diversities. Secondly, open-pit-mine monitoring demands high levels of accuracy, which justifies our efforts to improve the developed UAV-PS to its maximum capacities. The hardware of the system consisted of an electric-powered helicopter, a high-resolution digital camera, and an inertial navigation system. The software of the system included the in-house programs specifically designed for camera calibration, platform calibration, system integration, onboard data acquisition, flight planning and ground control point (GCP) detection. The detailed features of the system are discussed in the thesis, and solutions are proposed in order to enhance the system and its photogrammetric outputs. The accuracy of the results was evaluated under various mapping conditions, including direct georeferencing and indirect georeferencing with different numbers, distributions and types of ground control points. Additionally, the effects of imaging configuration and network stability on modeling accuracy were assessed. The second part of this thesis concentrates on improving the techniques of sparse and dense reconstruction. The proposed solutions are alternatives to traditional aerial photogrammetry techniques, properly adapted to specific characteristics of unmanned, low-altitude imagery. Firstly, a method was developed for robust sparse matching and epipolar-geometry estimation. The main achievement of this method was its capacity to handle a very high percentage of outliers (errors among corresponding points) with remarkable computational efficiency (compared to the state-of-the-art techniques). Secondly, a block bundle adjustment (BBA) strategy was proposed based on the integration of intrinsic camera calibration parameters as pseudo-observations to Gauss-Helmert model. The principal advantage of this strategy was controlling the adverse effect of unstable imaging networks and noisy image observations on the accuracy of self-calibration. The sparse implementation of this strategy was also performed, which allowed its application to data sets containing a lot of tie points. Finally, the concepts of intrinsic curves were revisited for dense stereo matching. The proposed technique could achieve a high level of accuracy and efficiency by searching only through a small fraction of the whole disparity search space as well as internally handling occlusions and matching ambiguities. These photogrammetric solutions were extensively tested using synthetic data, close-range images and the images acquired from the gravel-pit mine. Achieving absolute 3D mapping accuracy of 11±7 mm illustrated the success of this system for high-precision modeling of the environment. / Résumé : Les images acquises à l’aide d’aéronefs sans pilote (ASP) permettent de produire des données de résolutions spatiales et temporelles uniques pour la modélisation tridimensionnelle (3D). Les solutions développées pour ce secteur d’activité sont principalement basées sur des concepts de photogrammétrie et peuvent être identifiées comme des systèmes photogrammétriques embarqués sur aéronefs sans pilote (SP-ASP). Ils sont utilisés dans plusieurs applications environnementales où l’information géospatiale et visuelle est essentielle. Ces applications incluent notamment la gestion des ressources naturelles (ex. : agriculture de précision), la sécurité publique et militaire (ex. : gestion du trafic), les services d’ingénierie (ex. : inspection de bâtiments) et les services de santé publique (ex. : épidémiologie et gestion des risques). Les SP-ASP peuvent être subdivisés en catégories selon les besoins en termes de précision et de résolution. En effet, dans certains cas, tel qu’en ingénierie, l’information sur l’environnement doit être de haute précision et de haute résolution (ex. : modélisation 3D avec une précision et une résolution inférieure à un centimètre). Pour d’autres applications, tel qu’en gestion de la faune sauvage, des niveaux de précision et de résolution moindres peut être suffisants (ex. : résolution de l’ordre de quelques décimètres). Cependant, même dans ce type d’applications les caractéristiques des SP-ASP devraient être prises en considération dans le développement des systèmes et dans leur utilisation, et ce, pour atteindre les résultats visés. À cet égard, cette thèse présente une revue exhaustive des applications de l’imagerie aérienne acquise par ASP et de déterminer les challenges les plus courants. Cette étude a également permis d’établir les caractéristiques et exigences spécifiques des SP-ASP qui sont généralement ignorées ou partiellement discutées dans les études récentes. En conséquence, la première partie de cette thèse traite des aspects méthodologiques et d’expérimentation de la mise en place d’un SP-ASP. Le système développé a été évalué pour la modélisation précise d’une gravière et utilisé pour réaliser des mesures de changement volumétrique. Cette application a été retenue pour deux raisons principales. Premièrement, ce type de milieu fournit un environnement difficile pour la modélisation, et ce, en termes de changement d’échelle, de changement de relief du terrain ainsi que la grande diversité de structures et de textures. Deuxièment, le suivi de mines à ciel ouvert exige un niveau de précision élevé, ce qui justifie les efforts déployés pour mettre au point un SP-ASP de haute précision. Les composantes matérielles du système consistent en un ASP à propulsion électrique de type hélicoptère, d’une caméra numérique à haute résolution ainsi qu’une station inertielle. La composante logicielle est composée de plusieurs programmes développés particulièrement pour calibrer la caméra et la plateforme, intégrer les systèmes, enregistrer les données, planifier les paramètres de vol et détecter automatiquement les points de contrôle au sol. Les détails complets du système sont abordés dans la thèse et des solutions sont proposées afin d’améliorer le système et la qualité des données photogrammétriques produites. La précision des résultats a été évaluée sous diverses conditions de cartographie, incluant le géoréférencement direct et indirect avec un nombre, une répartition et des types de points de contrôle variés. De plus, les effets de la configuration des images et la stabilité du réseau sur la précision de la modélisation ont été évalués. La deuxième partie de la thèse porte sur l’amélioration des techniques de reconstruction éparse et dense. Les solutions proposées sont des alternatives aux techniques de photogrammétrie aérienne traditionnelle et adaptée aux caractéristiques particulières de l’imagerie acquise à basse altitude par ASP. Tout d’abord, une méthode robuste de correspondance éparse et d’estimation de la géométrie épipolaire a été développée. L’élément clé de cette méthode est sa capacité à gérer le pourcentage très élevé des valeurs aberrantes (erreurs entre les points correspondants) avec une efficacité de calcul remarquable en comparaison avec les techniques usuelles. Ensuite, une stratégie d’ajustement de bloc basée sur l’intégration de pseudoobservations du modèle Gauss-Helmert a été proposée. Le principal avantage de cette stratégie consistait à contrôler les effets négatifs du réseau d’images instable et des images bruitées sur la précision de l’autocalibration. Une implémentation éparse de cette stratégie a aussi été réalisée, ce qui a permis de traiter des jeux de données contenant des millions de points de liaison. Finalement, les concepts de courbes intrinsèques ont été revisités pour l’appariement stéréo dense. La technique proposée pourrait atteindre un haut niveau de précision et d’efficacité en recherchant uniquement dans une petite portion de l’espace de recherche des disparités ainsi qu’en traitant les occlusions et les ambigüités d’appariement. Ces solutions photogrammétriques ont été largement testées à l’aide de données synthétiques, d’images à courte portée ainsi que celles acquises sur le site de la gravière. Le système a démontré sa capacité a modélisation dense de l’environnement avec une très haute exactitude en atteignant une précision 3D absolue de l’ordre de 11±7 mm.