This master thesis studies the learning of dense feature descriptors where camera poses are the only supervisory signal. The use of camera poses as a supervisory signal has only been published once before, and this thesis expands on this previous work by utilizing a couple of different techniques meant increase the robustness of the method, which is particularly important when not having access to ground-truth correspondences. Firstly, an adaptive robust loss is utilized to better differentiate inliers and outliers. Secondly, statistical properties during training are both enforced and adapted to, in an attempt to alleviate problems with uncertainties introduced by not having true correspondences available. These additions are shown to slightly increase performance, and also highlights some key ideas related to prediction certainty and robustness when working with camera poses as a supervisory signal. Finally, possible directions for future work are discussed.

Το πρόβλημα της εκτίμησης θέσης και του προσανατολισμού της κάμερας από τις γνωστές 3D συντεταγμένες n σημείων της σκηνής και των 2D προβολών τους στο επίπεδο της εικόνας, είναι γνωστό στην βιβλιογραφία ως "Perspective n Point(PnP)" πρόβλημα. Το πρόβλημα αυτό συναντάται σε πολλά σημαντικά επιστημονικά πεδία όπως αυτά της υπολογιστικής όρασης, της ρομποτικής, της αυτοματοποιημένης χαρτογραφίας, της επαυξημένης πραγματικότητας κ.α, και μπορεί να θεωρηθεί ως μια ειδική περίπτωση του προβλήματος βαθμονόμησης της κάμερας. Η ανάγκη για την ανάπτυξη ρωμαλέων και χαμηλής πολυπλοκότητας μεθόδων για την επίλυση του "PnP" προβλήματος σε πραγματικό χρόνο έχει αναδειχθεί από πολλούς ερευνητές τα τελευταία χρόνια. Στο πλαίσιο της προτεινόμενης διπλωματικής μελετήθηκαν σε βάθος οι πιο σημαντικές μέθοδοι που έχουν προταθεί στην διεθνή βιβλιογραφία μέχρι σήμερα. / The perspective camera pose estimation problem, given known 3D coordinates in the world coordinate system and their correspondent 2D image projections, is known as "Perspective n Point(PnP)" problem. It has many applications in Photogrammetry, Computer Vision, Robotics, Augmented Reality and can be considered as a special case of camera calibration problem. The need for development of robust and simultaneously low computational complexity real time solutions for the PnP problem is very strong as it has attracted much attention in the literature during the last few years. In this master thesis, most significant as well as state of the art techniques which provide solutions to camera pose estimation problem have been thoroughly studied.

Computer graphics imagery (CGI) has enabled many useful applications in training, defense, and entertainment. One such application, CGI simulation, is a real-time system that allows users to navigate through and interact with a virtual rendition of an existing environment. Creating such systems is difficult, but particularly burdensome is the task of designing and constructing the internal representation of the simulation content. Authoring this content on a computer usually requires great expertise and many man-hours of labor. Computational stereo and image-based rendering offer possibilities to automatically create simulation content without user assistance. However, these technologies have largely been limited to creating content from only a few photographs, severely limiting the simulation experience. The purpose of this dissertation is to enable the process of automated content creation for large numbers of photographs. The workflow goal consists of a user photographing any real-world environment intended for simulation, and then loading the photographs into the computer. The theoretical and algorithmic contributions of the dissertation are then used to transform the photographs into the data required for real-time exploration of the photographed locale. This permits a rich simulation experience without the laborious effort required to author the content manually. To approach this goal we make four contributions to the fields of computer vision and image-based rendering: an improved point correspondence methodology, an adjacency graph construction algorithm for unordered photographs, a pose estimation ordering for unordered image sets, and an image-based rendering algorithm that interpolates omnidirectional images to synthesize novel views. We encapsulate our contributions into a working system that we call Vision-Based Rendering (VBR). With our VBR system we are able to automatically create simulation content from a large unordered collection of input photographs. However, there are severe restrictions in the type of image content our present system can accurately simulate. Photographs containing large regions of high frequency detail are incorporated very accurately, but images with smooth color gradations, including most indoor photographs, create distracting artifacts in the final simulation. Thus our system is a significant and functional step toward the ultimate goal of simulating any real-world environment.

Dans ce travail de thèse, nous proposons plusieurs algorithmespermettant d'estimer des paramètres évoluant sur des groupes de Lie. Cesalgorithmes s’inscrivent de manière générale dans un cadre bayésien, ce qui nouspermet d'établir une notion d'incertitude sur les paramètres estimés. Pour ce faire,nous utilisons une généralisation de la distribution normale multivariée aux groupesde Lie, appelée distribution normale concentrée sur groupe de Lie.Dans une première partie, nous nous intéressons au problème du filtrage de Kalmanà temps discret et continu-discret où l’état et les d’observations appartiennent à desgroupes de Lie. Cette étude nous conduit à la proposition de deux filtres ; le CD-LGEKFqui permet de résoudre un problème à temps continu-discret et le D-LG-EKF quipermet de résoudre un problème à temps discret.Dans une deuxième partie, nous nous inspirons du lien entre optimisation et filtragede Kalman, qui a conduit au développement du filtrage de Kalman étendu itéré surespace euclidien, en le transposant aux groupes de Lie. Nous montrons ainsicomment obtenir une généralisation du filtre de Kalman étendu itéré aux groupes deLie, appelée LG-IEKF, ainsi qu’une généralisation du lisseur de Rauch-Tung-Striebelaux groupes de Lie, appelée LG-RTS.Finalement, dans une dernière partie, les concepts et algorithmes d’estimation surgroupes de Lie proposés dans la thèse sont utilisés dans le but de fournir dessolutions au problème de la cartographie d'un environnement à partir d'une caméramonoculaire d'une part, et au problème de la localisation d'une caméra monoculairese déplaçant dans un environnement préalablement cartographié d'autre part. / In this thesis, we derive novel parameter estimation algorithmsdedicated to parameters evolving on Lie groups. These algorithms are casted in aBayesian formalism, which allows us to establish a notion of uncertainty for theestimated parameters. To do so, a generalization of the multivariate normaldistribution to Lie groups, called concentrated normal distribution on Lie groups, isemployed.In a first part, we generalize the Continuous-Discrete Extended Kalman Filter (CDEKF),as well as the Discrete Extended Kalman Filter (D-EKF), to the case where thestate and the observations evolve on Lie groups. We obtain two novel algorithmscalled Continuous-Discrete Extended Kalman Filter on Lie Groups (CD-LG-EKF) andDiscrete Extended Kalman Filter on Lie Groups (D-LG-EKF).In a second part, we focus on bridging the gap between the formulation of intrinsicnon linear least squares criteria and Kalman filtering/smoothing on Lie groups. Wepropose a generalization of the Euclidean Iterated Extended Kalman Filter (IEKF) toLie groups, called LG-IEKF. We also derive a generalization of the Rauch-Tung-Striebel smoother (RTS), also known as Extended Kalman Smoother, to Lie groups,called LG-RTS.Finally, the concepts and algorithms presented in the thesis are employed in a seriesof applications. Firstly, we propose a novel simultaneous localization and mappingapproach. Secondly we develop an indoor camera localization framework. For thislatter purpose, we derived a novel Rao-Blackwellized particle smoother on Liegroups, which builds upon the LG-IEKF and the LG-RTS.

<p>This thesis presents a complete and fully automatic method for estimating the volume of an airbag, through all stages of its inflation, with multiple synchronized high-speed cameras.</p><p>Using recorded contours of the inflating airbag, its visual hull is reconstructed with a novel method: The intersections of all back-projected contours are first identified with an accelerated epipolar algorithm. These intersections, together with additional points sampled from concave surface regions of the visual hull, are then Delaunay triangulated to a connected set of tetrahedra. Finally, the visual hull is extracted by carving away the tetrahedra that are classified as inconsistent with the contours, according to a voting procedure.</p><p>The volume of an airbag's visual hull is always larger than the airbag's real volume. By projecting a known synthetic model of the airbag into the cameras, this volume offset is computed, and an accurate estimate of the real airbag volume is extracted. </p><p>Even though volume estimates can be computed for all camera setups, the cameras should be specially posed to achieve optimal results. Such poses are uniquely found for different airbag models with a separate, fully automatic, simulated annealing algorithm.</p><p>Satisfying results are presented for both synthetic and real-world data.</p>

This thesis presents a complete and fully automatic method for estimating the volume of an airbag, through all stages of its inflation, with multiple synchronized high-speed cameras. Using recorded contours of the inflating airbag, its visual hull is reconstructed with a novel method: The intersections of all back-projected contours are first identified with an accelerated epipolar algorithm. These intersections, together with additional points sampled from concave surface regions of the visual hull, are then Delaunay triangulated to a connected set of tetrahedra. Finally, the visual hull is extracted by carving away the tetrahedra that are classified as inconsistent with the contours, according to a voting procedure. The volume of an airbag's visual hull is always larger than the airbag's real volume. By projecting a known synthetic model of the airbag into the cameras, this volume offset is computed, and an accurate estimate of the real airbag volume is extracted. Even though volume estimates can be computed for all camera setups, the cameras should be specially posed to achieve optimal results. Such poses are uniquely found for different airbag models with a separate, fully automatic, simulated annealing algorithm. Satisfying results are presented for both synthetic and real-world data.

Tato disertační práce se zabývá odhadem pózy kamery z korespondencí 3D a 2D přímek, tedy tzv. perspektivním problémem n  přímek (angl. Perspective- n -Line, PnL). Pozornost je soustředěna na případy s velkým počtem čar, které mohou být efektivně řešeny metodami využívajícími lineární formulaci PnL. Dosud byly známy pouze metody pracující s korespondencemi 3D bodů a 2D přímek. Na základě tohoto pozorování byly navrženy dvě nové metody založené na algoritmu přímé lineární transformace (angl. Direct Linear Transformation, DLT): Metoda DLT-Plücker-Lines pracující s korespondencemi 3D a 2D přímek a metoda DLT-Combined-Lines pracující jak s korespondencemi 3D bodů a 2D přímek, tak s korespondencemi 3D přímek a 2D přímek. Ve druhém případě je redundantní 3D informace využita k redukci minimálního počtu požadovaných korespondencí přímek na 5 a ke zlepšení přesnosti metody. Navržené metody byly důkladně testovány za různých podmínek včetně simulovaných a reálných dat a porovnány s nejlepšími existujícími PnL metodami. Metoda DLT-Combined-Lines dosahuje výsledků lepších nebo srovnatelných s nejlepšími existujícími metodami a zároveň je značně rychlá. Tato disertační práce také zavádí jednotný rámec pro popis metod pro odhad pózy kamery založených na algoritmu DLT. Obě navržené metody jsou definovány v tomto rámci.

This thesis deals with the usage of optical signal in aircraft navigation systems. The solution is based upon the creation of runway identi cation system working with the record of an onboard camera.

The automotive safety company Veoneer are producers of high end driver visual assistance systems, but the knowledge about the absolute accuracy of their dynamic calibration algorithms that estimate the vehicle’s orientation is limited. In this thesis, a novel measurement system is proposed to be used in gathering reference data of a vehicle’s orientation as it is in motion, more specifically the pitch and roll angle of the vehicle. Focus has been to estimate how the uncertainty of the measurement system is affected by errors introduced during its construction, and to evaluate its potential in being a viable tool in gathering reference data for algorithm performance evaluation. The system consisted of three laser distance sensors mounted on the body of the vehicle, and a range of data acquisition sequences with different perturbations were performed by driving along a stretch of road in Linköping with weights loaded in the vehicle. The reference data were compared to camera system data where the bias of the calculated angles were estimated, along with the dynamic behaviour of the camera system algorithms. The experimental results showed that the accuracy of the system exceeded 0.1 degrees for both pitch and roll, but no conclusions about the bias of the algorithms could be drawn as there were systematic errors present in the measurements. / Bilsäkerhetsföretaget Veoneer är utvecklare av avancerade kamerasystem inom förarassistans, men kunskapen om den absoluta noggrannheten i deras dynamiska kalibreringsalgoritmer som skattar fordonets orientering är begränsad. I denna avhandling utvecklas och testas ett nytt mätsystem för att samla in referensdata av ett fordons orientering när det är i rörelse, mer specifikt dess pitchvinkel och rollvinkel. Fokus har legat på att skatta hur osäkerheten i mätsystemet påverkas av fel som introducerats vid dess konstruktion, samt att utreda dess potential när det kommer till att vara ett gångbart alternativ för att samla in referensdata för evaluering av prestandan hos algoritmerna. Systemet bestod av tre laseravståndssensorer monterade på fordonets kaross. En rad mätförsök utfördes med olika störningar introducerade genom att köra längs en vägsträcka i Linköping med vikter lastade i fordonet. Det insamlade referensdatat jämfördes med data från kamerasystemet där bias hos de framräknade vinklarna skattades, samt att de dynamiska egenskaperna kamerasystemets algoritmer utvärderades. Resultaten från mätförsöken visade på att noggrannheten i mätsystemet översteg 0.1 grader för både pitchvinklarna och rollvinklarna, men några slutsatser kring eventuell bias hos algoritmerna kunde ej dras då systematiska fel uppstått i mätresultaten.

Definované markery tvoří základ určování polohy kamery pro velké množství aplikací s rozšířenou realitou, v případě že jsou přísné požadavky na rychlost a robustnost. Tato práce popisuje účinnou metodu pro určení pózy kamery pomocí Uniformního pole markerů a několik realistických aplikací na bázi popsané metody. Metoda je velice výpočetně levná a poskytuje spolehlivou detekci pro několik výpočetních platforem, včetně běžných chytrých telefonů. Markery jako část zobrazené informace na monitorech jsou použité v této práci pro určení relativní orientaci mezi poskytovatelem obsahu a užívatelským zařízením, sloužícím pro výběr prvků užívatelského rozhraní při  interakci a migraci úkolů. Ve filmařském průmyslu poskytuje popsaná metoda pro zjištění polohy kamery jako součást klíčovaní pozadí filmářům živý náhled virtuální scény. Výsledky ukazují, že popsaná metoda pro detekci pole markerů má srovnatelnou úspěšnost a přesnost v porovnání s ostatními metodami na bázi markerů a je několikrát rýchlejší. Aplikace zahrnuté v této práci podle výsledků testů jsou životaschopné - rychlejší a levnější - alternativy k existujícím řešením.