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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

3D scanning of transparent objects

Eren, Gönen 22 October 2010 (has links) (PDF)
Many practical tasks in industry, such as automatic inspection or robot vision, often require scanning of three-dimensional shapes with non-contact techniques. However, transparent objects, such as those made of glass, still pose difficulties for classical scanning techniques. The reconstruction of surface geometry for transparent objects is complicated by the fact that light is transmitted through, refracted and in some cases reflected by the surface. Current approaches can only deal relatively well with sub-classes of objects. The algorithms are still very specific and not generally applicable. Furthermore, many techniques require considerable acquisition effort and careful calibration. This thesis proposes a new method of determining the surface shape of transparent objects. The method is based on local surface heating and thermal imaging. First, the surface of the object is heated with a laser source. A thermal image is acquired, and pixel coordinates of the heated point are calculated. Then, the 3D coordinates of the surface are computed using triangulation and the initial calibration of the system. The process is repeated by moving the transparent object to recover its surface shape. This method is called Scanning From Heating. Considering the laser beam as a point heating source and the surface of the object locally flat at the impact zone, the Scanning From Heating method is extended to obtain the surface normals of the object, in addition to the 3D world coordinates. A scanner prototype based on Scanning From Heating method has been developed during the thesis.
12

Reconstruction de formes tubulaires à partir de nuages de points : application à l’estimation de la géométrie forestière / Tubular shapes reconstruction from point clouds : applications to the forests geometry

Ravaglia, Joris 14 December 2017 (has links)
Le coeur de cette thèse porte sur la modélisation géométrique et introduit une méthode robuste d'extraction de formes tubulaires à partir de nuages de points. Nous avons choisi de tester nos méthodes dans le contexte applicatif de la foresterie pour mettre en valeur la robustesse de nos algorithmes.Nos méthodes intègrent les normales aux points, il est donc nécessaire de les pré-calculer. Notre premier développement a alors consisté à présenter une méthode rapide d'estimation de normales. Pour ce faire nous avons approximé localement la géométrie du nuage de points en utilisant des "patchs" lisses dont la taille s'adapte à la complexité locale des nuages de points.Nos travaux se sont ensuite concentrés sur l’extraction robuste de formes tubulaires dans des nuages de points occlus, bruités et de densité inhomogène. Nous avons développé une variante de la transformée de Hough que nous avons couplé à une proposition de contours actifs indépendants de leur paramétrisation. Notre méthode a été validée en environnement forestier pour reconstruire des troncs d'arbre afin d'en relever les qualités par comparaison à des méthodes existantes.La reconstruction de troncs d'arbre ouvre d'autres questions dont la segmentation des arbres d'une placette forestière. Nous proposons également une méthode de segmentation pour isoler les différents objets d'un jeu de données.Durant nos travaux nous avons utilisé des approches de modélisation pour répondre à des questions géométriques, et nous les avons appliqué à des problématiques forestières. Il en résulte un pipeline de traitements cohérent qui, bien qu'illustré sur des données forestières, est applicable dans des contextes variés. / The core of this thesis concerns geometric modelling and introduces a fast and robust method for the extraction of tubular shapes from point clouds. We chose to test our method in the difficult applicative context of forestry in order to highlight the robustness of our algorithms.Our methods integrate normal vectors, thus they have to be pre-computed. Our first development consisted in the development of a fast normal estimation method on point cloud. To do so, we locally approximated the point cloud geometry using smooth "patches" of points which size adapts to the local complexity of the point cloud geometry.We then focused our work on the robust extraction of tubular shapes from dense, occluded, noisy point clouds suffering from non-homogeneous sampling density. We developed a variant of the Hough transform and combined this research with a new definition of parametrisation-invariant active contours. We validated our method in complex forest environments with the reconstruction of tree stems to emphasize its advantages and compare it to existing methods.Tree stem reconstruction also opens new perspectives halfway in between forestry and geometry such as the segmentation of trees from a forest plot. Therefore we propose a segmentation approach capable of isolating objects inside a point cloud.During our work we used modelling approaches to answer geometric questions and we applied our methods to forestry problems. Therefore, our studies result in a processing pipeline adapted to forest point cloud analyses, but the general geometric algorithms we propose can also be applied in various contexts.
13

Reconstruction de formes tubulaires à partir de nuages de points : application à l’estimation de la géométrie forestière

Ravaglia, Joris January 2017 (has links)
Les capacités des technologies de télédétection ont augmenté exponentiellement au cours des dernières années : de nouveaux scanners fournissent maintenant une représentation géométrique de leur environnement sous la forme de nuage de points avec une précision jusqu'ici inégalée. Le traitement de nuages de points est donc devenu une discipline à part entière avec ses problématiques propres et de nombreux défis à relever. Le coeur de cette thèse porte sur la modélisation géométrique et introduit une méthode robuste d'extraction de formes tubulaires à partir de nuages de points. Nous avons choisi de tester nos méthodes dans le contexte applicatif difficile de la foresterie pour mettre en valeur la robustesse de nos algorithmes et leur application à des données volumineuses. Nos méthodes intègrent les normales aux points comme information supplémentaire pour atteindre les objectifs de performance nécessaire au traitement de nuages de points volumineux.Cependant, ces normales ne sont généralement pas fournies par les capteurs, il est donc nécessaire de les pré-calculer.Pour préserver la rapidité d'exécution, notre premier développement a donc consisté à présenter une méthode rapide d'estimation de normales. Pour ce faire nous avons approximé localement la géométrie du nuage de points en utilisant des "patchs" lisses dont la taille s'adapte à la complexité locale des nuages de points. Nos travaux se sont ensuite concentrés sur l’extraction robuste de formes tubulaires dans des nuages de points denses, occlus, bruités et de densité inhomogène. Dans cette optique, nous avons développé une variante de la transformée de Hough dont la complexité est réduite grâce aux normales calculées. Nous avons ensuite couplé ces travaux à une proposition de contours actifs indépendants de leur paramétrisation. Cette combinaison assure la cohérence interne des formes reconstruites et s’affranchit ainsi des problèmes liés à l'occlusion, au bruit et aux variations de densité. Notre méthode a été validée en environnement complexe forestier pour reconstruire des troncs d'arbre afin d'en relever les qualités par comparaison à des méthodes existantes. La reconstruction de troncs d'arbre ouvre d'autres questions à mi-chemin entre foresterie et géométrie. La segmentation des arbres d'une placette forestière est l'une d’entre elles. C'est pourquoi nous proposons également une méthode de segmentation conçue pour contourner les défauts des nuages de points forestiers et isoler les différents objets d'un jeu de données. Durant nos travaux nous avons utilisé des approches de modélisation pour répondre à des questions géométriques, et nous les avons appliqué à des problématiques forestières.Il en résulte un pipeline de traitements cohérent qui, bien qu'illustré sur des données forestières, est applicable dans des contextes variés. / Abstract : The potential of remote sensing technologies has recently increased exponentially: new sensors now provide a geometric representation of their environment in the form of point clouds with unrivalled accuracy. Point cloud processing hence became a full discipline, including specific problems and many challenges to face. The core of this thesis concerns geometric modelling and introduces a fast and robust method for the extraction of tubular shapes from point clouds. We hence chose to test our method in the difficult applicative context of forestry in order to highlight the robustness of our algorithms and their application to large data sets. Our methods integrate normal vectors as a supplementary geometric information in order to achieve the performance goal necessary for large point cloud processing. However, remote sensing techniques do not commonly provide normal vectors, thus they have to be computed. Our first development hence consisted in the development of a fast normal estimation method on point cloud in order to reduce the computing time on large point clouds. To do so, we locally approximated the point cloud geometry using smooth ''patches`` of points which size adapts to the local complexity of the point cloud geometry. We then focused our work on the robust extraction of tubular shapes from dense, occluded, noisy point clouds suffering from non-homogeneous sampling density. For this objective, we developed a variant of the Hough transform which complexity is reduced thanks to the computed normal vectors. We then combined this research with a new definition of parametrisation-invariant active contours. This combination ensures the internal coherence of the reconstructed shapes and alleviates issues related to occlusion, noise and variation of sampling density. We validated our method in complex forest environments with the reconstruction of tree stems to emphasize its advantages and compare it to existing methods. Tree stem reconstruction also opens new perspectives halfway in between forestry and geometry. One of them is the segmentation of trees from a forest plot. Therefore we also propose a segmentation approach designed to overcome the defects of forest point clouds and capable of isolating objects inside a point cloud. During our work we used modelling approaches to answer geometric questions and we applied our methods to forestry problems. Therefore, our studies result in a processing pipeline adapted to forest point cloud analyses, but the general geometric algorithms we propose can also be applied in various contexts.
14

Interactive Depth-Aware Effects for Stereo Image Editing

Abbott, Joshua E. 24 June 2013 (has links) (PDF)
This thesis introduces methods for adding user-guided depth-aware effects to images captured with a consumer-grade stereo camera with minimal user interaction. In particular, we present methods for highlighted depth-of-field, haze, depth-of-field, and image relighting. Unlike many prior methods for adding such effects, we do not assume prior scene models or require extensive user guidance to create such models, nor do we assume multiple input images. We also do not require specialized camera rigs or other equipment such as light-field camera arrays, active lighting, etc. Instead, we use only an easily portable and affordable consumer-grade stereo camera. The depth is calculated from a stereo image pair using an extended version of PatchMatch Stereo designed to compute not only image disparities but also normals for visible surfaces. We also introduce a pipeline for rendering multiple effects in the order they would occur physically. Each can be added, removed, or adjusted in the pipeline without having to reapply subsequent effects. Individually or in combination, these effects can be used to enhance the sense of depth or structure in images and provide increased artistic control. Our interface also allows editing the stereo pair together in a fashion that preserves stereo consistency, or the effects can be applied to a single image only, thus leveraging the advantages of stereo acquisition even to produce a single photograph.
15

Zoneamento agroclimático para a produção de roseiras (Rosaceae spp.) no Rio Grande do Sul / Agroclimatic Zoning to the Roses (Rosaceae spp.) production in Rio Grande do Sul

Wollmann, Cássio Arthur 29 June 2011 (has links)
O objetivo geral desta pesquisa foi propor um zoneamento agroclimático para a produção de roseiras (Rosaceae spp.) realizada ao ar livre no Rio Grande do Sul, classificando o Estado em áreas Aptas, Marginais e Inaptas do ponto de vista das temperaturas médias sazonais e anuais. Zoneou-se, também, as condições climáticas de anos-padrões mais chuvoso, menos chuvoso e habitual, bem como fez-se levantamento dos sistemas atmosféricos predominantes nestes anos. Fez-se fundamentação teórica relativa ao tema, bem como se utilizou a base de dados climáticos cartografada do Atlas Agroclimático da FEPAGRO/RS. Tal base foi digitalizada com auxilio de SIG, bem como foi feita a construção do banco de dados, no qual foram atribuídas as características de aptidão, de área marginal e inapta do ponto de vista climático para cada um dos elementos climáticos analisados. Ainda, as áreas aptas e marginais foram subdivididas em quatro classes para melhor atender às exigências climáticas da rosa a todos os elementos analisados. As estações do outono e primavera mostraram-se como sendo as estações de maior aptidão climática para o cultivo das rosáceas. Apenas as estações de verão e inverno apresentaram áreas inaptas para o cultivo da rosa. Entretanto foram consideradas para todas as estações, e todos os anos-padrões analisados, restrições climáticas relacionadas às temperaturas máximas e mínimas médias e absolutas; às horas de frio abaixo de 10°C; às condições médias de umidade relativa superiores à 75%, à insolação inferior à 6 horas/dia; radiação solar inferior a 2000 Lux/dia; e às rajadas médias de vento superiores à 46 m/s. A análise anual não apresentou áreas inaptas, mas pode ser observado o surgimento de diferentes subclasses ligadas às áreas aptas e marginais ao cultivo da rosa. Dentre os sistemas atmosféricos definidores da zonação climática, pode-se destacar a MPA e FPA na primavera, MPV, MTA e MTC no verão, MPA e FE no outono, e MPA no inverno. Tanto pesquisadores quanto produtores de rosas, pela sua percepção do tempo e do clima, afirmaram que as condições climáticas do Rio Grande do Sul, especialmente as grandes variações térmicas e elevada umidade do ar, bem como a baixa insolação, não são recomendadas para o cultivo da roseira. / This research concerned to propose an agroclimatic zoning for production rose (Rosaceae spp.) in outdoors conditions in Rio Grande do Sul, ranking the state in suitable areas, marginal and unsuitable from the viewpoint of the seasonal mean temperature and annual . Also, years-patterns weather was classified as year-wetter, less rainy and usual, and did a survey of prevailing weather systems in recent years. It was made the theoretical foundation on the subject, and we used the climatic data base of the Agroclimatic Maps from FEPAGRO / RS. This base was scanned with the aid of GIS, and was made to build the database in which they were awarded the characteristics of fitness, unfit and marginal area of the climatic point of view for each of the climatic elements analyzed. Still, the fit and marginal areas were divided into four classes to better meet the climatic requirements of the rose of all the factors analyzed. The seasons of spring and autumn proved to be the largest fitness stations climate for the cultivation of roses. Only the summer and winter showed areas unfit for cultivation of the rose. However they were considered for all seasons and all analyzed years-patterns, environmental constraints related to maximum and minimum temperatures and average absolute; the chilling hours below 10°C, the average conditions of relative humidity higher than 75%, the insolation less than 6 hours/day, solar radiation below 2000 Lux/day and the average wind gusts greater than 46 m/s. An annual review showed areas not suitable, but can be observed the emergence of different sub-classes related to marginal areas and suitable for the cultivation of the rose. Among the systems that define the atmospheric climate zoning, we can highlight the MPA and FPA in the spring, MPV, MTA and MTC in summer, FE and MPA in autumn, and MPA in the winter. Both researchers and producers of roses, by the perception of weather and climate, said the weather in Rio Grande do Sul, especially the large temperature fluctuations and high humidity and low insolation, are not recommended for cultivation rosebush.
16

Zoneamento agroclimático para a produção de roseiras (Rosaceae spp.) no Rio Grande do Sul / Agroclimatic Zoning to the Roses (Rosaceae spp.) production in Rio Grande do Sul

Cássio Arthur Wollmann 29 June 2011 (has links)
O objetivo geral desta pesquisa foi propor um zoneamento agroclimático para a produção de roseiras (Rosaceae spp.) realizada ao ar livre no Rio Grande do Sul, classificando o Estado em áreas Aptas, Marginais e Inaptas do ponto de vista das temperaturas médias sazonais e anuais. Zoneou-se, também, as condições climáticas de anos-padrões mais chuvoso, menos chuvoso e habitual, bem como fez-se levantamento dos sistemas atmosféricos predominantes nestes anos. Fez-se fundamentação teórica relativa ao tema, bem como se utilizou a base de dados climáticos cartografada do Atlas Agroclimático da FEPAGRO/RS. Tal base foi digitalizada com auxilio de SIG, bem como foi feita a construção do banco de dados, no qual foram atribuídas as características de aptidão, de área marginal e inapta do ponto de vista climático para cada um dos elementos climáticos analisados. Ainda, as áreas aptas e marginais foram subdivididas em quatro classes para melhor atender às exigências climáticas da rosa a todos os elementos analisados. As estações do outono e primavera mostraram-se como sendo as estações de maior aptidão climática para o cultivo das rosáceas. Apenas as estações de verão e inverno apresentaram áreas inaptas para o cultivo da rosa. Entretanto foram consideradas para todas as estações, e todos os anos-padrões analisados, restrições climáticas relacionadas às temperaturas máximas e mínimas médias e absolutas; às horas de frio abaixo de 10°C; às condições médias de umidade relativa superiores à 75%, à insolação inferior à 6 horas/dia; radiação solar inferior a 2000 Lux/dia; e às rajadas médias de vento superiores à 46 m/s. A análise anual não apresentou áreas inaptas, mas pode ser observado o surgimento de diferentes subclasses ligadas às áreas aptas e marginais ao cultivo da rosa. Dentre os sistemas atmosféricos definidores da zonação climática, pode-se destacar a MPA e FPA na primavera, MPV, MTA e MTC no verão, MPA e FE no outono, e MPA no inverno. Tanto pesquisadores quanto produtores de rosas, pela sua percepção do tempo e do clima, afirmaram que as condições climáticas do Rio Grande do Sul, especialmente as grandes variações térmicas e elevada umidade do ar, bem como a baixa insolação, não são recomendadas para o cultivo da roseira. / This research concerned to propose an agroclimatic zoning for production rose (Rosaceae spp.) in outdoors conditions in Rio Grande do Sul, ranking the state in suitable areas, marginal and unsuitable from the viewpoint of the seasonal mean temperature and annual . Also, years-patterns weather was classified as year-wetter, less rainy and usual, and did a survey of prevailing weather systems in recent years. It was made the theoretical foundation on the subject, and we used the climatic data base of the Agroclimatic Maps from FEPAGRO / RS. This base was scanned with the aid of GIS, and was made to build the database in which they were awarded the characteristics of fitness, unfit and marginal area of the climatic point of view for each of the climatic elements analyzed. Still, the fit and marginal areas were divided into four classes to better meet the climatic requirements of the rose of all the factors analyzed. The seasons of spring and autumn proved to be the largest fitness stations climate for the cultivation of roses. Only the summer and winter showed areas unfit for cultivation of the rose. However they were considered for all seasons and all analyzed years-patterns, environmental constraints related to maximum and minimum temperatures and average absolute; the chilling hours below 10°C, the average conditions of relative humidity higher than 75%, the insolation less than 6 hours/day, solar radiation below 2000 Lux/day and the average wind gusts greater than 46 m/s. An annual review showed areas not suitable, but can be observed the emergence of different sub-classes related to marginal areas and suitable for the cultivation of the rose. Among the systems that define the atmospheric climate zoning, we can highlight the MPA and FPA in the spring, MPV, MTA and MTC in summer, FE and MPA in autumn, and MPA in the winter. Both researchers and producers of roses, by the perception of weather and climate, said the weather in Rio Grande do Sul, especially the large temperature fluctuations and high humidity and low insolation, are not recommended for cultivation rosebush.
17

3D scanning of transparent objects / Numérisation 3D d'objets transparents

Eren, Gönen 22 October 2010 (has links)
Beaucoup de tâches pratiques dans l'industrie, tels que l'inspection automatique ou la vision robotique, nécessitent souvent de numérisation de formes en trois dimensions (3D) avec des techniques non-contact. Toutefois, les objets transparents, tels que ceux en verre, posent encore des difficultés pour les techniques classiques de numérisation. La reconstruction de la géométrie de surface pour les objets transparents est compliquée par le fait que la lumière est transmise à travers, réfracté et dans certains cas, réfléchie par la surface. Les approches actuelles ne peut traiter que les sous-classes d'objets. Les algorithmes sont encore très spécifiques et ne sont généralement pas applicables. En outre, de nombreuses techniques exigent un effort considérable d'acquisition et de calibration. Cette thèse propose une nouvelle méthode de détermination de la forme de la surface des objets transparents. La méthode est basée sur le chauffage locale de la surface et sur l'imagerie thermique. Tout d'abord, la surface de l'objet est chauffé avec une source laser. Une image thermique est acquis, et les coordonnées en pixels du point d'échauffement sont calculés. Ensuite, les coordonnées 3D de la surface sont déterminées en utilisant triangulation et l'étalonnage initial du système. Le processus est répété en déplaçant l'objet transparent pour reprendre sa forme de surface complète. Cette méthode est appelée "Scanning From Heating". Considérant le faisceau laser comme une source de chauffage point et la surface de l'objet localement plane à la zone d'impact, la méthode est utilisée pour obtenir les normales de la surface de l'objet, en plus des coordonnées 3D. Un prototype base sur cette méthode a été développé pendant la thèse. / Many practical tasks in industry, such as automatic inspection or robot vision, often require scanning of three-dimensional shapes with non-contact techniques. However, transparent objects, such as those made of glass, still pose difficulties for classical scanning techniques. The reconstruction of surface geometry for transparent objects is complicated by the fact that light is transmitted through, refracted and in some cases reflected by the surface. Current approaches can only deal relatively well with sub-classes of objects. The algorithms are still very specific and not generally applicable. Furthermore, many techniques require considerable acquisition effort and careful calibration. This thesis proposes a new method of determining the surface shape of transparent objects. The method is based on local surface heating and thermal imaging. First, the surface of the object is heated with a laser source. A thermal image is acquired, and pixel coordinates of the heated point are calculated. Then, the 3D coordinates of the surface are computed using triangulation and the initial calibration of the system. The process is repeated by moving the transparent object to recover its surface shape. This method is called Scanning From Heating. Considering the laser beam as a point heating source and the surface of the object locally flat at the impact zone, the Scanning From Heating method is extended to obtain the surface normals of the object, in addition to the 3D world coordinates. A scanner prototype based on Scanning From Heating method has been developed during the thesis.
18

Design centrum HANÁK NÁBYTEK a.s., Popůvky u Kojetína - příprava a organizace výstavby objektu / Design center HANÁK NÁBYTEK a.s., Popůvky u Kojetína - project planning and management of construction

Izsová, Radka January 2014 (has links)
This thesis addresses the Design centrum HANÁK NÁBYTEK a.s., Popůvky u Kojetína - This is a new object had the basement and a second floor. The thesis includes - Technical report on the construction technology of the project , which are described in each chapter building equipment, coordination of building relationships with the wider transport routes , the study of the main technological stages, the design of the main building machines and mechanisms. There is a solution on time and financial plan object , the schedule object SO03 - Rapid technological and construction timetable and plan for securing material resources SO03 object . This thesis addresses the technological specification for excavation work with the control and test plan then is solved problems of chemical anchoring pillars object SO203 , which are included tensile tests on chemical anchors.
19

Some Advanced Model Selection Topics for Nonparametric/Semiparametric Models with High-Dimensional Data

Fang, Zaili 13 November 2012 (has links)
Model and variable selection have attracted considerable attention in areas of application where datasets usually contain thousands of variables. Variable selection is a critical step to reduce the dimension of high dimensional data by eliminating irrelevant variables. The general objective of variable selection is not only to obtain a set of cost-effective predictors selected but also to improve prediction and prediction variance. We have made several contributions to this issue through a range of advanced topics: providing a graphical view of Bayesian Variable Selection (BVS), recovering sparsity in multivariate nonparametric models and proposing a testing procedure for evaluating nonlinear interaction effect in a semiparametric model. To address the first topic, we propose a new Bayesian variable selection approach via the graphical model and the Ising model, which we refer to the ``Bayesian Ising Graphical Model'' (BIGM). There are several advantages of our BIGM: it is easy to (1) employ the single-site updating and cluster updating algorithm, both of which are suitable for problems with small sample sizes and a larger number of variables, (2) extend this approach to nonparametric regression models, and (3) incorporate graphical prior information. In the second topic, we propose a Nonnegative Garrote on a Kernel machine (NGK) to recover sparsity of input variables in smoothing functions. We model the smoothing function by a least squares kernel machine and construct a nonnegative garrote on the kernel model as the function of the similarity matrix. An efficient coordinate descent/backfitting algorithm is developed. The third topic involves a specific genetic pathway dataset in which the pathways interact with the environmental variables. We propose a semiparametric method to model the pathway-environment interaction. We then employ a restricted likelihood ratio test and a score test to evaluate the main pathway effect and the pathway-environment interaction. / Ph. D.

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