Room layout generation is the problem of generating a drawing or a digital model of an existing room from a set of measurements such as laser data or images. The generation of floor plans can find application in the building industry to assess the quality and the correctness of an ongoing construction w.r.t. the initial model, or to quickly sketch the renovation of an apartment. Real estate industry can rely on automatic generation of floor plans to ease the process of checking the livable surface and to propose virtual visits to prospective customers. As for the general public, the room layout can be integrated into mixed reality games to provide a better immersiveness experience, or used in other related augmented reality applications such room redecoration. The goal of this industrial thesis (CIFRE) is to investigate and take advantage of the state-of-the art mobile devices in order to automate the process of generating room layouts. Nowadays, modern mobile devices usually come a wide range of sensors, such as inertial motion unit (IMU), RGB cameras and, more recently, depth cameras. Moreover, tactile touchscreens offer a natural and simple way to interact with the user, thus favoring the development of interactive applications, in which the user can be part of the processing loop. This work aims at exploiting the richness of such devices to address the room layout generation problem. The thesis has three major contributions. We first show how the classic problem of detecting vanishing points in an image can benefit from an a-priori given by the IMU sensor. We propose a simple and effective algorithm for detecting vanishing points relying on the gravity vector estimated by the IMU. A new public dataset containing images and the relevant IMU data is introduced to help assessing vanishing point algorithms and foster further studies in the field. As a second contribution, we explored the state of-the-art of real-time localization and map optimization algorithms for RGB-D sensors. Real-time localization is a fundamental task to enable augmented reality applications, and thus it is a critical component when designing interactive applications. We propose an evaluation of existing algorithms for the common desktop set-up in order to be employed on a mobile device. For each considered method, we assess the accuracy of the localization as well as the computational performances when ported on a mobile device. Finally, we present a proof of concept of application able to generate the room layout relying on a Project Tango tablet equipped with an RGB-D sensor. In particular, we propose an algorithm that incrementally processes and fuses the 3D data provided by the sensor in order to obtain the layout of the room. We show how our algorithm can rely on the user interactions in order to correct the generated 3D model during the acquisition process.

Une des techniques alternatives au GPS pour le développement d’un système d’assistance à la navigationpédestre en milieux urbains est la vision embarquée. La localisation du porteur de la caméra s’appuie alorssur l’estimation de la pose à partir des images acquises au cours du cheminement. En s’inspirant destravaux antérieurs sur la navigation autonome de robots, cette thèse explore deux approches dans le cadrespécifique de la localisation pédestre. La première méthode de localisation s’appuie sur des appariementsde primitives images avec une cartographie 3D pré-estimée de l’environnement. Elle permet une estimationprécise de la pose complète de la caméra (6 ddl), mais les expérimentations montrent des limitationscritiques de robustesse et temps de calcul liées à l’étape de mise en correspondance. Une solutionalternative est proposée en utilisant les points de fuite. L’orientation de la caméra (3ddl) est estimée defaçon robuste et rapide par le suivi de 3 points de fuites orthogonaux dans une séquence vidéo. L’algorithmedéveloppé permet une localisation pédestre indoor en deux étapes : une phase d’apprentissage hors lignedéfinit un itinéraire de référence en sélectionnant des images clef au long du parcours, puis, en phase delocalisation, une position approximative mais réaliste du porteur est estimée en temps réel en comparant lesorientations de la caméra dans l’image courante et celle de référence. / One of the alternative techniques to GPS for the development of pedestrian navigation assistive systems inurban environments is embedded vision. The walker localization is, then, based on the camera poseestimation from images acquired during the path. Inspired by previous work on autonomous navigation ofmobile robots, this thesis explores two approaches in the specific context of pedestrian localization. The firstlocalization method is based on image primitive matching with a pre-estimated 3D map of the environment. Itallows an accurate estimate of the complete pose of the camera (6 dof), but experiments show criticallimitations of robustness and computation time related to the matching step. An alternative solution isproposed using vanishing points. Robust and fast camera orientation (3 dof) is estimated by tracking threeorthogonal vanishing points in a video sequence. The developed algorithm allows indoor pedestrianlocalization in two steps: an off-line learning step defines a reference path by selecting key frames along theway, then, in localization step, an approximate but realistic position of the walker is estimated in real time bycomparing the orientation of the camera in the current image and that of reference.

abstract: Toward the ambitious long-term goal of a fleet of cooperating Flexible Autonomous Machines operating in an uncertain Environment (FAME), this thesis addresses various perception and control problems in autonomous aerial robotics. The objective of this thesis is to motivate the use of perspective cues in single images for the planning and control of quadrotors in indoor environments. In addition to providing empirical evidence for the abundance of such cues in indoor environments, the usefulness of these perspective cues is demonstrated by designing a control algorithm for navigating a quadrotor in indoor corridors. An Extended Kalman Filter (EKF), implemented on top of the vision algorithm, serves to improve the robustness of the algorithm to changing illumination. In this thesis, vanishing points are the perspective cues used to control and navigate a quadrotor in an indoor corridor. Indoor corridors are an abundant source of parallel lines. As a consequence of perspective projection, parallel lines in the real world, that are not parallel to the plane of the camera, intersect at a point in the image. This point is called the vanishing point of the image. The vanishing point is sensitive to the lateral motion of the camera and hence the quadrotor. By tracking the position of the vanishing point in every image frame, the quadrotor can navigate along the center of the corridor. Experiments are conducted using the Augmented Reality (AR) Drone 2.0. The drone is equipped with the following componenets: (1) 720p forward facing camera for vanishing point detection, (2) 240p downward facing camera, (3) Inertial Measurement Unit (IMU) for attitude control , (4) Ultrasonic sensor for estimating altitude, (5) On-board 1 GHz Processor for processing low level commands. The reliability of the vision algorithm is presented by flying the drone in indoor corridors. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2018

Made available in DSpace on 2015-05-15T11:46:23Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1404779 bytes, checksum: fa23dbf1324f104548ef91fcbbf20fba (MD5) Previous issue date: 2014-09-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we study questions related to the existence of positive solutions for some classes of quasilinear Schrödinger equations, with hypotheses on the potential that permit this potential to vanish at infinity. In order to use variational methods to obtain our results, we make some changes of variables to obtain some semilinear equations, whose associated functionals are well defined in a classical Sobolev spaces. We also work with these equations on an Orlicz type space whose energy functional satisfy the geometric properties of the Mountain Pass Theorem. We still use the penalty technique due to Del Pino and Felmer and the Moser iteration method to obtain estimates in L1 norm, which are fundamental to our study. / Neste trabalho, estudamos questões relacionadas à existência de soluções positivas para algumas classes de equações de Schrödinger quasilineares, com hipóteses sobre o potencial que o possibilita se anular no infinito. Afim de usarmos métodos variacionais na obtenção de nossos resultados, aplicamos mudança de variáveis para reduzirmos as equações quasilineares a equações semilineares. Os funcionais associados a essas novas equações estão bem definidos em espaços de Sobolev clássicos e em espaços tipo Orlicz e satisfazem as propriedades geométricas do Teorema do Passo da Montanha. Ainda utilizamos a técnica de penalização de Del Pino e Felmer e o método de iteração de Moser para obtenção de estimativas, fundamentais para o nosso estudo, na norma L1.

Neste trabalho estudamos superfícies com a propriedade que suas componentes irredutíveis são superfícies tóricas. Em particular, apresentamos uma fórmula para calcular a obstrução de Euler local destas superfícies. Como uma aplicação desta fórmula, calculamos a obstrução de Euler local para algumas famílias de superfícies determinantais. Além disso, definimos a característica de Euler evanescente de uma superfície tórica normal Xσ, damos uma fórmula para calcular tal invariante e relacionamos este número com a segunda multiplicidade polar de Xσ. Apresentamos também, uma fórmula para a obstrução de Euler de uma função f : Xσ → C e para o número de Brasselet de tal função. Como uma aplicação deste resultado, calculamos a obstrução de Euler de um tipo de polinômio definido em uma família de superfícies determinantais. / In this work we study surfaces with the property that their irreducible components are toric surfaces. In particular, we present a formula to compute the local Euler obstruction of such surfaces. As an application of this formula we compute the local Euler obstruction for some families of determinantal surfaces. Furthermore, we define the vanishing Euler characteristic of a normal toric surface Xσ, we give a formula to compute it, and we relate this number with the second polar multiplicity of Xσ. We also present a formula for the Euler obstruction of a function f : Xσ → C and for the Brasselet number of it. As an application of this result we compute the Euler obstruction of a type of polynomial on a family of determinantal surfaces.

A redução de custos e a melhora do processo produtivo são essenciais para o aumento da rentabilidade e da produtividade das áreas agrícolas. O investimento em tecnologia se torna, portanto, fundamental em um mundo cada vez mais competitivo. Neste trabalho é apresentado o desenvolvimento de um método de extração da posição de máquinas agrícolas, em relação às linhas de cultivo, a partir do processamento de imagens fornecidas por uma câmera de vídeo colorida. A posição extraída é a informação básica utilizada em um sistema de direcionamento automático, permitindo determinar quais ações devam ser tomadas para manter a máquina em sua trajetória. O correto posicionamento da máquina sobre as linhas de cultivo melhora o processo de pulverização, ocasionando a redução de custos e o aumento da produtividade da área. O método proposto está embasado nos conceitos de ponto de fuga e busca antecipada. Essas técnicas permitiram simplificar o processamento das imagens e conseqüentemente a redução do tempo de processamento. Essas características, aliadas ao correto posicionamento da câmera, devem permitir que o método proposto possa ser utilizado no controle de máquinas agrícolas que operam em grandes velocidades como os pulverizadores. / Cost reduction and productive process improvement are essential to increase yield in agricultural areas. Investments in technology become, therefore, important in a competitive world. This work presents a novel approach for extracting agricultural machine position, with respect to crop rows, processing images captured by a color video camera. The correct machine positioning in crop rows can improve agricultural processes such as spraying, decreasing the costs and increasing the area yield. The proposed method is based on the look-ahead and vanishing points techniques. These techniques allow the reduction of the algorithm complexity and, therefore, the reduction of the processing time. These characteristics added to the camera position may allow the system to control agricultural machines that run at high speeds, such as sprayers.

UAVs have gained in popularity and the number of applications has soared over the past years, ranging from leisure to commercial activities. This thesis is discussing specifically railroad applications, which is a domain rarely explored. Two different aspects are analysed. While developing a new application or migrating a ground-based system to UAV platform, the different challenges encountered are often unknown. Therefore, this thesis highlights the most important ones to take into consideration during the development process. From a more technical aspect, the implementation of autonomous guidance for UAVs over railroads using vanishing point extraction is studied. Two different algorithms are presented and compared, the first one is using line extraction method whereas the second uses joint activities of Gabor filters. The results demonstrate that the applied methodologies provide good results and that a significant difference exists between both algorithms in terms of computation time. A second implementation tackling the detection of railway topologies to enable the use on multiple rail road configurations is discussed. A first technique is presented using exclusively vanishing points for the detection, however, the results for complex images are not satisfactory. Therefore, a second method is studied using line characteristics on top of the previous algorithm. This second implementation has proven to give good results.

Dans ce travail, nous étudions les surfaces dont les composantes irréductibles sont des surfaces toriques. En particulier, nous donnons une formule pour calculer l'obstruction d'Euler locale de ces surfaces. Comme application de cette formule, nous calculons l'obstruction d'Euler locale pour certaines familles de surfaces déterminantales. De plus, nous définissons et donnons une formule pour calculer la caractéristique d'Euler évanescente d'une surface torique normale $X_{sigma}$. Nous montrons que ce nombre est relié à la seconde multiplicité polaire de $X_{sigma}$. Nous présentons aussi une formule pour l'obstruction d'Euler d'une fonction $f: X_{sigma} to mathbb{C}$ et pour le nombre de Brasselet d'une telle fonction. Comme application de ce résultat nous calculons l'obstruction d'Euler d'un type de polynôme sur une famille de surfaces déterminantales. / In this work we study surfaces with the property that their irreducible components are toric surfaces. In particular, we present a formula to compute the local Euler obstruction of such surfaces. As an application of this formula we compute the local Euler obstruction for some families of determinantal surfaces. Furthermore, we define the vanishing Euler characteristic of a normal toric surface $X_{sigma}$, we give a formula to compute it, and we relate this number with the second polar multiplicity of $X_{sigma}$. We also present a formula for the Euler obstruction of a function $f: X_{sigma} to mathbb{C}$ and for the Brasselet number of it. As an application of this result we compute the Euler obstruction of a type of polynomial on a family of determinantal surfaces.

La géométrie symplectique et la géométrie complexe sont intimement liées, en particulier par les techniques asymptotiquement holomorphes de Donaldson et Auroux d'une part et par les travaux d’Eliashberget et Cieliebak sur la pseudoconvexité d'autre part. Les travaux présentés dans cette thèse sont motivés par ces deux liens. On donne d’abord la caractérisation symplectique suivante des constantes de Seshadri. Dans une variété complexe, la constante de Seshadri d’une classe de Kähler entière en un point est la borne supérieure des capacités de boules standard admettant, pour une certaine forme de Kähler dans cette classe, un plongement holomorphe et iso-Kähler de codimension 0 centré en ce point. Ce critère était connu de Eckl en 2014 ; on en donne une preuve différente. La deuxième partie est motivée par la question suivante de Donaldson : <<Toute sphère lagrangienne d'une variété projective complexe est-elle un cycle évanescent d'une déformation complexe vers une variété à singularité conique ?>> D'une part, on présente toute sous-variété lagrangienne close d’une variété symplectique/kählérienne close dont les périodes relatives sont entières comme lieu des minima d’une exhaustion <<convexe>> définie sur le complémentaire d'une section hyperplane symplectique/complexe. Dans le cadre kählérien, <<convexe>> signifie strictement plurisousharmonique tandis que dans le cadre symplectique, cela signifie de Lyapounov pour un champ de Liouville. D'autre part, on montre que toute sphère lagrangienne d'un domaine de Stein qui est le lieu des minima d’une fonction <<convexe>> est un cycle évanescent d'une déformation complexe sur le disque vers un domaine à singularité conique. / Symplectic geometry and complex geometry are closely related, in particular by Donaldson and Auroux’s asymptotically holomorphic techniques and by Eliashberg and Cieliebak’s work on pseudoconvexity. The work presented in this thesis is motivated by these two connections. We first give the following symplectic characterisation of Seshadri constants. In a complex manifold, the Seshadri constant of an integral Kähler class at a point is the upper bound on the capacities of standard balls admitting, for some Kähler form in this class, a codimension 0 holomorphic and iso-Kähler embedding centered at this point. This criterion was known by Eckl in 2014; we give a different proof of it. The second part is motivated by Donaldon’s following question: ‘Is every Lagrangian sphere of a complex projective manifold a vanishing cycle of a complex deformation to a variety with a conical singularity?’ On the one hand, we present every closed Lagrangian submanifold of a closed symplectic/Kähler manifold whose relative periods are integers as the lowest level set of a ‘convex’ exhaustion defined on the complement of a symplectic/complex hyperplane section. In the Kähler setting ‘complex’ means strictly plurisubharmonic while in the symplectic setting it refers to the existence of a Liouville pseudogradient. On the other hand, we prove that any Lagrangian sphere of a Stein domain which is the lowest level-set of a ‘convex’ function is a vanishing cycle of some complex deformation over the disc to a variety with a conical singularity.

In this thesis, we present a collection of newly obtained results concerning the existence of vanishing viscosity solutions to the one-dimensional compressible Euler equations of gas dynamics, with and without geometric structure. We demonstrate the existence of such vanishing viscosity solutions, which we show to be entropy solutions, to the transonic nozzle problem and spherically symmetric Euler equations in Chapter 4, in both cases under the simple and natural assumption of relative finite-energy. In Chapter 5, we show that the viscous solutions of the one-dimensional compressible Navier-Stokes equations converge, as the viscosity tends to zero, to an entropy solution of the Euler equations, again under the assumption of relative finite-energy. In so doing, we develop a compactness framework for the solutions and approximate solutions to the Euler equations under the assumption of a physical pressure law. Finally, in Chapter 6, we consider the Euler equations in special relativity, and show the existence of bounded entropy solutions to these equations. In the process, we also construct fundamental solutions to the entropy equations and develop a compactness framework for the solutions and approximate solutions to the relativistic Euler equations.