Dans le contexte de la vision par ordinateur cette thèse étudie le problème d’appariement d’images dans le cadre de la télédétection pour la géologie. Plus précisément, nous disposons dans ce travail de deux images de la même scène géographique, mais acquises à partir de deux points de vue différents et éventuellement à un autre moment. La tâche d’appariement est d'associer à chaque pixel de la première image un pixel de la seconde image.Bien que ce problème soit relativement facile pour les êtres humains, il reste difficile à résoudre par un ordinateur. De nombreuses approches pour traiter cette tâche ont été proposées. Les techniques les plus prometteuses formulent la tâche comme un problème d'optimisation numérique. Malheureusement, le nombre d'inconnues ainsi que la nature de la fonction à optimiser rendent ce problème extrêmement difficile à résoudre. Cette thèse étudie deux approches avec un schéma multi-échelle pour résoudre le problème numérique sous-jacent / This thesis studies the computer vision problem of image registration in the context of geological remote sensing surveys. More precisely we dispose in this work of two images picturing the same geographical scene but acquired from two different view points and possibly at a different time. The task of registration is to associate to each pixel of the first image its counterpart in the second image.While this problem is relatively easy for human-beings, it remains an open problem to solve it with a computer. Numerous approaches to address this task have been proposed. The most promising techniques formulate the task as a numerical optimization problem. Unfortunately, the number of unknowns along with the nature of the objective function make the optimization problem extremely difficult to solve. This thesis investigates two approaches along with a coarsening scheme to solve the underlying numerical problem

This thesis presents the development and the seismic performance evaluation of steel MRFs with nonlinear replaceable links. Although existing MRFs can provide life safety during a design level earthquake, they are expected to sustain significant damage at the locations of flexural yielding fuses in the beams. The design of the fuse is also interlinked with the design of the beam, often resulting in over-design. These drawbacks can be mitigated by introducing replaceable links at the locations of expected inelastic action. Four full-scale beam-to-column subassemblages with two link types were tested under cyclic loading: i) double channels with bolted web connections, ii) W-sections with bolted end plate connections. The experiments demonstrated that MRFs with replaceable links can provide strength and ductility equivalent to existing MRFs. Finite element models were then developed to capture the observed experimental responses, including local buckling, bolt slipping, and bolt bearing. Finally, preliminary design guidelines were proposed.

This thesis presents the development and the seismic performance evaluation of steel MRFs with nonlinear replaceable links. Although existing MRFs can provide life safety during a design level earthquake, they are expected to sustain significant damage at the locations of flexural yielding fuses in the beams. The design of the fuse is also interlinked with the design of the beam, often resulting in over-design. These drawbacks can be mitigated by introducing replaceable links at the locations of expected inelastic action. Four full-scale beam-to-column subassemblages with two link types were tested under cyclic loading: i) double channels with bolted web connections, ii) W-sections with bolted end plate connections. The experiments demonstrated that MRFs with replaceable links can provide strength and ductility equivalent to existing MRFs. Finite element models were then developed to capture the observed experimental responses, including local buckling, bolt slipping, and bolt bearing. Finally, preliminary design guidelines were proposed.

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L’objectif de cette thèse est l’étude de l’évolution de champ scalaire transporté par un écoulement à partir d’une séquence d’images temporelles. L’estimation du champ de vitesse d’un écoulement turbulent est d’une importance majeure pour mieux comprendre le phénomène physique. Jusqu’à présent, le problème de la turbulence est généralement ignoré dans l’équation de mouvement des méthodes existantes. Les images contiennent une information discrète correspondant à la taille du pixel. Selon le niveau de turbulence de l’écoulement, les résolutions des pixels et du temps peuvent devenir trop grandes pour négliger l’effet des petites échelles (sous-pixel) sur le champ de vitesse. Nous proposons pour cela, une équation de mouvement définie par l’équation de transport de concentration filtrée pour laquelle un modèle classique de viscosité turbulente sous-maille est introduit afin de tenir compte de cet effet. Nous utilisons pour formuler le problème, une approche Markovienne. Une méthode de multirésolution par décomposition pyramidale, sans transformation d’image intermédiaire au cours du processus, est proposée. Cela permet de diminuer le nombre d’opérations sur les images. La méthode d’optimisation utilisée, couplée avec une approche multigrille, permet d’obtenir le champ de vitesse réel optimal. Notre approche est testée sur des séquences d’images synthétiques et réelles (expérience PIV et tempête de sable à partir d’image de télédétection) avec des nombres de Reynolds élevés. Les comparaisons avec des approches existantes sont très prometteuses. / The objective of this thesis is to study the evolution of scalar field carried by a flow from a temporal image sequence. The estimation of the velocity field of turbulent flow is of major importance for understanding the physical phenomenon. Up to now the problem of turbulence is generally ignored in the flow equation of existing methods. An information given by image is discrete at pixel size. Depending on the turbulent rate of the flow, pixel and time resolutions may become too large to neglect the effect of sub-pixel small-scales on the pixel velocity field. For this, we propose a flow equation defined by a filtered concentration transport equation where a classic turbulent sub-grid eddy viscosity model is introduced in order to account for this effect. To formulate the problem, we use a Markovian approach. An unwarping multiresolution by pyramidal decomposition is proposed which reduces the number of operations on images. The optimization coupled with a multigrid approach allows to estimate the optimal 2D real velocity field. Our approach is tested on synthetic andreal image sequences (PIV laboratory experiment and remote sensing data of dust storm event) with high Reynolds number. Comparisons with existing approaches are very promising.

Submitted by VANESSA JORDÃO MARCATO FERNANDES null (vanessamarcato@yahoo.com.br) on 2017-01-30T18:15:29Z No. of bitstreams: 1 fernandes_vjm_tese.pdf: 25329126 bytes, checksum: 92c837eb39ae9af74c15ccf278cd2a84 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-03T16:39:11Z (GMT) No. of bitstreams: 1 fernandes_vjm_dr_prud.pdf: 25329126 bytes, checksum: 92c837eb39ae9af74c15ccf278cd2a84 (MD5) / Made available in DSpace on 2017-02-03T16:39:11Z (GMT). No. of bitstreams: 1 fernandes_vjm_dr_prud.pdf: 25329126 bytes, checksum: 92c837eb39ae9af74c15ccf278cd2a84 (MD5) Previous issue date: 2016-12-19 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esse trabalho propõe o desenvolvimento de um método para a extração automática de contornos de telhados de edifícios com a combinação de dados de Varredura a LASER Aerotransportado (VLA) e dados fotogramétricos e campos aleatórios de Markov (MRF). Inicialmente, um Modelo Digital de Superfície normalizado (MDSn) é gerado através da diferença entre o Modelo Digital de Superfície (MDS) e o Modelo Digital de Terreno (MDT), obtidos a partir da nuvem de pontos LASER. Em seguida, o MDSn é segmentado para a obtenção dos polígonos que representam objetos altos da cena. Esses polígonos são projetados na imagem para restringir o espaço de busca para a segmentação da imagem em regiões. Esse processo possibilita a extração de polígonos na imagem que representem objetos altos. O processo de identificação de contornos de telhados, em meio aos objetos altos detectados na imagem, na etapa anterior, é realizado através da otimização de uma função de energia estabelecida com base em MRF que modela propriedades específicas de contornos de telhados de edifícios. No modelo MRF são utilizados tanto os polígonos extraídos da imagem quanto os extraídos dos dados VLA. A função de energia é otimizada pelo método Algoritmo Genético (AG). O método proposto nesse trabalho foi avaliado com base em dados reais - imagens aéreas de alta resolução e dados VLA. Os resultados obtidos na avaliação experimental mostraram que a metodologia funciona adequadamente na tarefa de extrair os contornos de telhados de edifícios. A função de energia proposta associada ao método de otimização AG diferenciou corretamente os contornos de telhados de edifícios dos demais objetos altos presentes nas cenas. Os contornos de telhados extraídos apresentam boa qualidade, o que é evidenciado por meio dos índices de completeza e correção obtidos pela avaliação numérica. Com base nos índices médios obtidos para cada experimento, têm-se as médias de completeza e correção para os experimentos iguais a 90,96% e 98,99%, respectivamente. Os valores máximos de completeza e correção são de 99,19% e 99,94%, respectivamente, e os valores mínimos de 78,08% e 97,46%, respectivamente. Os menores valores de completeza estão associados às áreas de oclusão por vegetação e presença de sombras. / This paper proposes a method for the automatic extraction of building roof contours through a combination of Airborne Laser Scanner (ALS) and photogrammetric data, and Markov Random Field (MRF). Initially, a normalized digital surface model (nDSM) is generated on the basis of the difference between the digital surface model and the digital terrain model, obtained from the LiDAR point cloud. Then the nDSM is segmented to obtain the polygons representing aboveground objects. These polygons are projected onto image to restrict the search space for image segmentation into regions. This process enables the extraction of polygons in the image representing aboveground objects. Building roof contours are identified from among the aboveground objects in the image by optimizing a Markov-random-field-based energy function that embodies roof contour specific properties. In the MRF model are used both polygons extracted from image and from ALS data. The energy function is optimized by the Genetic Algorithm (GA) method. The method proposed in this work was evaluated based on real data - high-resolution aerial images and ALS data. The results obtained in the experimental evaluation showed that the methodology works adequately in the task of extracting the contours of building roofs. The proposed energy function associated with the GA optimization method correctly differentiated the building roof contours from the other high objects present in the scenes. The extracted roof contours show good quality, which is evidenced by the indexes of completeness and correctness obtained by numerical evaluation. Based on the mean indexes obtained for each experiment, the average completeness and correctness for the experiments were equal to 90.96% and 98.99%, respectively. The maximum completeness and correctness values are 99.19% and 99.94%, respectively, and the minimum values are 78.08% and 97.46%, respectively. The lowest values of completeness are associated to the vegetation occlusion areas and presence of shadows. / FAPESP: 2012/22332-2

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