Дисертації з теми "Direction Reconstruction"
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Wang, Fan. "Alternating direction methods for image recovery." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1406.
Повний текст джерелаStjärnholm, Sigfrid. "Ghosts of Our Past: Neutrino Direction Reconstruction Using Deep Neural Networks." Thesis, Uppsala universitet, Högenergifysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448765.
Повний текст джерелаNeutriner är de perfekta kosmiska budbärarna när det kommer till att undersöka de mest våldsamma och mystiska astronomiska och kosmologiska händelserna i vårt universum. Sannolikheten för en neutrinointeraktion är dock liten, och flödet av högenergetiska neutriner minskar kraftigt med energin. För att hitta dessa högenergetiska neutriner måste stora volymer av materia instrumenteras. Ett förslag på en design för en detektorstation kallas ARIANNA, och är framtagen för att detektera neutrinointeraktioner i den antarktiska isen genom att mäta radiopulser som bildas på grund av Askaryan-effekten. I denna rapport presenterar vi en metod baserad på toppmoderna maskininlärningstekniker för att rekonstruera riktningen på en inkommande neutrino, utifrån den radiostrålning som produceras. Vi tränade ett neuralt nätverk med simulerade data, som skapades med hjälp av ramverket NuRadioMC, och optimerade nätverket för att göra så bra förutsägelser som möjligt. Antalet interaktionshändelser som användes för att träna nätverket var i storleksordningen 106. Genom att undersöka två olika emissionsmodeller fann vi att nätverket kunde generalisera med god precision. Detta resulterade i en upplösning på 4-5°. Modellen kunde även göra goda förutsägelser på en datamängd trots att nätverket var tränat med en annan emissionsmodell. De resultat som metoden framtog är lovande, särskilt med avseende på att tidigare klassiska metoder inte har lyckats reproducera samma resultat utan att metoden redan innan vet var i isen som neutrinointeraktionen skedde. Nätverket kan också komma att användas för att utvärdera prestandan hos andra designförslag på detektorstationer för att snabbt och säkert ge en indikation på vilken design som kan tillhandahålla mest vetenskapligt värde.
Chen, Zhouye. "Reconstruction of enhanced ultrasound images from compressed measurements." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30222/document.
Повний текст джерелаThe interest of compressive sampling in ultrasound imaging has been recently extensively evaluated by several research teams. Following the different application setups, it has been shown that the RF data may be reconstructed from a small number of measurements and/or using a reduced number of ultrasound pulse emissions. According to the model of compressive sampling, the resolution of reconstructed ultrasound images from compressed measurements mainly depends on three aspects: the acquisition setup, i.e. the incoherence of the sampling matrix, the image regularization, i.e. the sparsity prior, and the optimization technique. We mainly focused on the last two aspects in this thesis. Nevertheless, RF image spatial resolution, contrast and signal to noise ratio are affected by the limited bandwidth of the imaging transducer and the physical phenomenon related to Ultrasound wave propagation. To overcome these limitations, several deconvolution-based image processing techniques have been proposed to enhance the ultrasound images. In this thesis, we first propose a novel framework for Ultrasound imaging, named compressive deconvolution, to combine the compressive sampling and deconvolution. Exploiting an unified formulation of the direct acquisition model, combining random projections and 2D convolution with a spatially invariant point spread function, the benefit of this framework is the joint data volume reduction and image quality improvement. An optimization method based on the Alternating Direction Method of Multipliers is then proposed to invert the linear model, including two regularization terms expressing the sparsity of the RF images in a given basis and the generalized Gaussian statistical assumption on tissue reflectivity functions. It is improved afterwards by the method based on the Simultaneous Direction Method of Multipliers. Both algorithms are evaluated on simulated and in vivo data. With regularization techniques, a novel approach based on Alternating Minimization is finally developed to jointly estimate the tissue reflectivity function and the point spread function. A preliminary investigation is made on simulated data
Lu, Chia-Chun [Verfasser], and Werner [Akademischer Betreuer] Hofmann. "An advanced direction reconstruction technique and application to the observation with H.E.S.S. / Chia-Chun Lu ; Betreuer: Werner Hofmann." Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1180299566/34.
Повний текст джерелаScrivanti, Gabriele Luca Giovanni. "Nonsmooth Nonconvex Variational Reconstruction for Electrical Impedance Tomography." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20700/.
Повний текст джерелаCumani, Paolo. "Analysis and estimation of the scientific performance of the GAMMA-400 experiment." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/10888.
Повний текст джерелаPer uno studio completo che parte dalla materia oscura e va all'origine e propagazione dei raggi cosmici, quello multi canale è uno degli approcci migliori per risolvere i quesiti irrisolti della fisica delle astroparticelle. GAMMA-400, grazie alla sua natura duale, dedita allo studio di raggi cosmici (elettroni fino alle energie del TeV e protoni e nuclei fino a 10^{15}-10^{16} eV) e raggi gamma (da 50 MeV fino a qualche TeV), si dedicherà allo studio di questi problemi. Lo scopo di questa tesi è lo studio delle prestazioni di GAMMA-400 per l'osservazione dei raggi gamma. Due diverse configurazioni della geometria sono state studiate: la "baseline" e la cosiddetta configurazione "enhanced". Le principali differenze tra queste due configurazioni si trovano nel tracciatore e nel calorimetro. Il tracciatore della "baseline" è composto da dieci piani di silicio, otto dei quali comprendono anche uno strato di ~0.1 X_0 di tungsteno. Il tracciatore della configurazione "enhanced" è invece composto da 25 piani di silicio inframezzati da uno strato di tungsteno di ~0.03 X_0. Il calorimetro della "baseline" è diviso in due sezioni: una parte composta da due piani di ioduro di cesio e silicio (chiamata "pre-shower") e una seconda parte composta da 28x28x12 cubi di ioduro di cesio. Il calorimetro della configurazione "enhanced" è invece composto solo da 20x20x20 cubi di ioduro di cesio. Per stimare le prestazioni ho sviluppato un algoritmo di ricostruzione della direzione del raggio gamma incidente. La ricostruzione può fare uso delle informazioni provenienti dal tracciatore, dal "pre-shower" o dal calorimetro, sia combinandole che singolarmente. Le direzioni ottenuta grazie alle informazioni del solo "pre-shower" o del solo calorimetro, anche se di minor risoluzione, possono essere utili per aumentare il numero di fotoni visti ad alta energia e per fornire le informazioni necessarie all'osservazione di transienti con i telescopi Cherenkov a terra. La risoluzione angolare utilizzando il tracciatore è migliore nel caso della configurazione "enhanced". A basse energie ciò è possibile grazie al minore tungsteno, e di conseguenza minor "scattering" multiplo, presente all'interno del tracciatore. Il calorimetro più piccolo, e più profondo, seppur ostacolando la ricostruzione dell'energia di fotoni ad alta energia, produce anche un numero minore di particelle di "backsplash" che peggiorano la ricostruzione delle tracce. L'area efficace totale della "baseline", potendo contare su un calorimetro più grande ed il "pre-shower", è più grande rispetto alla configurazione "enhanced". La risoluzione angolare, l'area efficace e la strategia di osservazione dello strumento contribuiscono alla sensitività per sorgenti puntiformi. La sensitività totale dello strumento è migliore per la "baseline" per energie maggiori di 5 GeV. Ho implementato un set prelminare di condizioni di "trigger" per lo studio dei raggi gamma tramite l'utilizzo delle informazioni del tracciatore. La necessità di rigettare la maggior parte delle particelle cariche deriva dall'elevato fondo presente in orbita (~10^6 protoni per raggio gamma) e una capacità di "downlink" limitata (~100 GB/day). Tra le due configurazioni si nota una differenza di meno dell'1% nel numero rimanente di protoni. Seppur promettente, tale risultato deve essere migliorato e possibili miglioramenti sono descritti nella tesi. Gli algoritmi di ricostruzione e "trigger" sono applicati all'analisi della possibilità di studiare "gamma-ray burst" (GRB) con la principale strumentazione a bordo di GAMMA-400. Una stima del numero di eventi non ricostruiti, perchè avvengono nel tempo morto tra due "trigger", è effettuata tramite la simulazione di un ipotetico GRB accoppiata ai tempi di arrivo dei fotoni presi dai dati reali di due GRB osservati da Fermi. In nessuna delle due configurazioni è visibile una percentuale significativa di "pile-up". Anche aumentando il flusso dei GRB la percentuale di eventi non ricostruiti non supera mai il 6%. Nonostante questo risultato, molto dipenderà dal disegno finale dell’elettronica di lettura dei rivelatori che potrebbe aumentare i tempi morti dello strumento.
XXVII Ciclo
1987
Yeh, Shu-Ying. "Reconstruction of foliations from directional information." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/158.
Повний текст джерелаFang, Hao. "Modélisation géométrique à différent niveau de détails d'objets fabriqués par l'homme." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4002/document.
Повний текст джерелаGeometric modeling of man-made objects from 3D data is one of the biggest challenges in Computer Vision and Computer Graphics. The long term goal is to generate a CAD-style model in an as-automatic-as-possible way. To achieve this goal, difficult issues have to be addressed including (i) the scalability of the modeling process with respect to massive input data, (ii) the robustness of the methodology to various defect-laden input measurements, and (iii) the geometric quality of output models. Existing methods work well to recover the surface of free-form objects. However, in case of manmade objects, it is difficult to produce results that approach the quality of high-structured representations as CAD models.In this thesis, we present a series of contributions to the field. First, we propose a classification method based on deep learning to distinguish objects from raw 3D point cloud. Second, we propose an algorithm to detect planar primitives in 3D data at different level of abstraction. Finally, we propose a mechanism to assemble planar primitives into compact polygonal meshes. These contributions are complementary and can be used sequentially to reconstruct city models at various level-of-details from airborne 3D data. We illustrate the robustness, scalability and efficiency of our methods on both laser and multi-view stereo data composed of man-made objects
Benli, Emrah. "OMNI-DIRECTIONAL INFRARED 3D RECONSTRUCTION AND TRACKING OF HUMAN TARGETS." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/5036.
Повний текст джерелаCollins, Karen Elizabeth. "Reconstruction of late quaternary ice-flow directions, east central Ellesmere Island, Northwest Territory." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6718.
Повний текст джерелаZhang, Mo. "Vers une méthode de restauration aveugle d’images hyperspectrales." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S132.
Повний текст джерелаWe propose in this thesis manuscript to develop a blind restoration method of single component blurred and noisy images where no prior knowledge is required. This manuscript is composed of three chapters: the first chapter focuses on state-of-art works. The optimization approaches for resolving the restoration problem are discussed first. Then, the main methods of restoration, so-called semi-blind ones because requiring a minimum of a priori knowledge are analysed. Five of these methods are selected for evaluation. The second chapter is devoted to comparing the performance of the methods selected in the previous chapter. The main objective criteria for evaluating the quality of the restored images are presented. Of these criteria, the l1 norm for the estimation error is selected. The comparative study conducted on a database of monochromatic images, artificially degraded by two blurred functions with different support size and three levels of noise, revealed the most two relevant methods. The first one is based on a single-scale alternating approach where both the PSF and the image are estimated alternatively. The second one uses a multi-scale hybrid approach, which consists first of alternatingly estimating the PSF and a latent image, then in a sequential next step, restoring the image. In the comparative study performed, the benefit goes to the latter. The performance of both these methods will be used as references to then compare the newly designed method. The third chapter deals with the developed method. We have sought to make the hybrid approach retained in the previous chapter as blind as possible while improving the quality of estimation of both the PSF and the restored image. The contributions covers a number of points. A first series concerns the redefinition of the scales that of the initialization of the latent image at each scale level, the evolution of the parameters for the selection of the relevant contours supporting the estimation of the PSF and finally the definition of a blind stop criterion. A second series of contributions concentrates on the blind estimation of the two regularization parameters involved in order to avoid having to fix them empirically. Each parameter is associated with a separate cost function either for the PSF estimation or for the estimation of a latent image. In the sequential step that follows, we refine the estimation of the support of the PSF estimated in the previous alternated step, before exploiting it in the process of restoring the image. At this level, the only a priori knowledge necessary is a higher bound of the support of the PSF. The different evaluations performed on monochromatic and hyperspectral images artificially degraded by several motion-type blurs with different support sizes, show a clear improvement in the quality of restoration obtained by the newly designed method in comparison to the best two state-of-the-art methods retained
Draycott, Samuel Thomas. "On the re-creation of site-specific directional wave conditions." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/31472.
Повний текст джерелаCao, Ning. "RECOVERING LOCAL NEURAL TRACT DIRECTIONS AND RECONSTRUCTING NEURAL PATHWAYS IN HIGH ANGULAR RESOLUTION DIFFUSION MRI." UKnowledge, 2013. http://uknowledge.uky.edu/cs_etds/13.
Повний текст джерелаStamm, Aymeric. "Diffusion directions imaging : reconstruction haute résolution des faisceaux de matière blanche par IRM de diffusion basse résolution angulaire." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00999556.
Повний текст джерелаSeyed, Aghamiry Seyed Hossein. "Imagerie sismique multi-paramètre par reconstruction de champs d'ondes : apport de la méthode des multiplicateurs de Lagrange avec directions alternées (ADMM) et des régularisations hybrides." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4090.
Повний текст джерелаFull Waveform Inversion (FWI) is a PDE-constrained optimization which reconstructs subsurface parameters from sparse measurements of seismic wavefields. FWI generally relies on local optimization techniques and a reduced-space approach where the wavefields are eliminated from the variables. In this setting, two bottlenecks of FWI are nonlinearity and ill-posedness. One source of nonlinearity is cycle skipping, which drives the inversion to spurious minima when the starting subsurface model is not kinematically accurate enough. Ill-posedness can result from incomplete subsurface illumination, noise and parameter cross-talks. This thesis aims to mitigate these pathologies with new optimization and regularization strategies. I first improve the wavefield reconstruction method (WRI). WRI extends the FWI search space by computing wavefields with a relaxation of the wave equation to match the data from inaccurate parameters. Then, the parameters are updated by minimizing wave equation errors with either alternating optimization or variable projection. In the former case, WRI breaks down FWI into to linear subproblems thanks to wave equation bilinearity. WRI was initially implemented with a penalty method, which requires a tedious adaptation of the penalty parameter in iterations. Here, I replace the penalty method by the alternating-direction method of multipliers (ADMM). I show with numerical examples how ADMM conciliates the search space extension and the accuracy of the solution at the convergence point with fixed penalty parameters thanks to the dual ascent update of the Lagrange multipliers. The second contribution is the implementation of bound constraints and non smooth Total Variation (TV) regularization in ADMM-based WRI. Following the Split Bregman method, suitable auxiliary variables allow for the de-coupling of the ℓ1 and ℓ2 subproblems, the former being solved efficiently with proximity operators. Then, I combine Tikhonov and TV regularizations by infimal convolution to account for the different statistical properties of the subsurface (smoothness and blockiness). At the next step, I show the ability of sparse promoting regularization in reconstruction the model when ultralong offset sparse fixed-spread acquisition such as those carried out with OBN are used. This thesis continues with the extension of the ADMM-based WRI to multiparameter reconstruction in vertical transversely isotropic (VTI) acoustic media. I first show that the bilinearity of the wave equation is satisfied for the elastodynamic equations. I discuss the joint reconstruction of the vertical wavespeed and epsilon in VTI media. Second, I develop ADMM-based WRI for attenuation imaging, where I update wavefield, squared-slowness, and attenuation in an alternating mode since viscoacoustic wave equation can be approximated, with a high degree of accuracy, as a multilinear equation. This alternating solving provides the necessary flexibility to taylor the regularization to each parameter class and invert large data sets. Then, I overcome some limitations of ADMM-based WRI when a crude initial model is used. In this case, the reconstructed wavefields are accurate only near the receivers. The inaccuracy of phase of the wavefields may be the leading factor which drives the inversion towards spurious minimizers. To mitigate the role of the phase during the early iterations, I update the parameters with phase retrieval, a process which reconstructs a signal from magnitude of linear mesurements. This approach combined with efficient regularizations leads to more accurate reconstruction of the shallow structure, which is decisive to drive ADMM-based WRI toward good solutions at higher frequencies. The last part of this PhD is devoted to time-domain WRI, where a challenge is to perform accurate wavefield reconstruction with acceptable computational cost
Hellstadius, Åsa. "A Quest for Clarity : Reconstructing Standards for the Patent Law Morality Exclusion." Doctoral thesis, Stockholms universitet, Juridiska institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-116261.
Повний текст джерелаSchaff, Florian Peter [Verfasser], Franz [Akademischer Betreuer] Pfeiffer, Hendrik [Gutachter] Dietz, Christian [Gutachter] Schroer, and Franz [Gutachter] Pfeiffer. "Directional Small-Angle X-ray Scattering Computed Tomography : Reconstruction of the Local Differential Cross Section / Florian Peter Schaff ; Gutachter: Hendrik Dietz, Christian Schroer, Franz Pfeiffer ; Betreuer: Franz Pfeiffer." München : Universitätsbibliothek der TU München, 2018. http://d-nb.info/1177241374/34.
Повний текст джерелаFranková, Markéta. "Návrh na rozšíření mateřské školy." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2013. http://www.nusl.cz/ntk/nusl-223756.
Повний текст джерелаBeaumont, Guillaume. "Traitements correctifs des effets de décohérence acoustique induits par les fluctuations du milieu de propagation : algorithmes d’estimation bayésienne des directions d’arrivée en milieu fluctuant." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2020. http://www.theses.fr/2020IMTA0200.
Повний текст джерелаThe purpose of these works is to propose new "physically informed" bayesian algorithms for DOA estimationin presence of random fluctuations due to the presence of internal waves in the propagation medium. First we will seehow to describe these fluctuations as a local perturbation of the celerity of the medium and then the impact of such waveson a propagated signal. In doing so, we are able to observe the corruption of this signal and to propose a statistical modelof this perturbation.After a state of the art of DOA estimation techniques in both constant an uncertain media, we will propose a modelizationof the fluctuations as a multiplicative phase noise following a multivariate gaussian distribution. Very close to thetheoretical model, this distribution allows us to develop the paSAMP algorithm, an Approximate Message Passingtechnique inspired form phase retrieval litterature which integrates this multiplicative phase noise model. In order to getcloser to the theoretical model, we propose to upgrade the phase noise prior using a multivariate Von Mises prior,allowing us to propose new bayesian methods for DOA estimation such as the VitAMin and the VistaBEM algorithms asextensions of resp. the paSAMP and the paVBEM algorithms. The first results on synthetic measurement considering aunivariate Von Mises phase noise seems are promising regarding the robustness of these algorithms to this new noisemodel.To conclude, we will see with the processing of real data from the ALMA campaign that it is possible to retrieve quantitiesfrom the theoretical model through signal statistics. Moreover, these quantities allow us to identify known phenomenon inthe propagation medium with only passive measurement. Such knowledge can then be use for tomography or as "smartinitialization" of the different algorithms
Sivapalan, Sabesan. "Human identification from video using advanced gait recognition techniques." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/77620/1/Sabesan_Sivapalan_Thesis.pdf.
Повний текст джерелаErdem, Mehmet Erkut. "Image-based Extraction Of Material Reflectance Properties Of A 3d Object." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1128784/index.pdf.
Повний текст джерела#64258
ectance properties of a three-dimensional (3D) object from its twodimensional (2D) images is explained. One of the main advantages of this system is that the reconstructed object can be rendered in real-time with photorealistic quality in varying illumination conditions. Bidirectional Re&
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ectance Distribution Functions (BRDFs) are used in representing the re&
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ectance of the object. The re&
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ectance of the object is decomposed into di&
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use and specular components and each component is estimated seperately. While estimating the di&
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use components, illumination-invariant images of the object are computed from the input images, and a global texture of the object is extracted from these images by using surface particles. The specular re&
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ectance data are collected from the residual images obtained by taking di&
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erence between the input images and corresponding illumination-invariant images, and a Lafortune BRDF model is &
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tted to these data. At the rendering phase, the di&
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use and specular components are blended into each other to achieve a photorealistic appearance of the reconstructed object.
Phan, Minh-Son. "Contribution à l'estimation de la similarité dans un ensemble de projections tomographiques non-orientées." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD041/document.
Повний текст джерелаCryo-electron microscopy is a tomographic technique allowing to reconstruct a 3D model of complex structure in biology from a set of acquired images. These images are known as the tomographic projections and are taken at unknown directions. The advantage of the cryo-electron microscopy is the 3D reconstruction at very high resolution. The reconstruction procedure consists of many steps such as projection alignment, projection classification, orientation estimation and projection refinement. During these steps, the distance between two projections is frequently measured. The work in this thesis aims at studying the distances mesured between two unknown-direction projections with the objective of improving the reconstruction result in the cryo-electron microscopy. The contribution of this thesis is the developement of a method for estimating the angular difference between two projections in 2D and 3D. Our method is based on the construction of a neighborhood graph whose vertices are the projections, whose edges link the projection neighbors and are weighted by a local approximation of the angular difference. The calculation of the weights relies on the projection moment properties. The proposed method has been tested on simulated images with different resolutions and at different noise levels. The comparison with others estimation methods of angular difference has been realised
Freijomil, Seoane Mariana. "Retorno(s) a Europa: genealogía de un modelo de reconstrucción histórica en el cine y la televisión contemporáneos." Doctoral thesis, Universitat Pompeu Fabra, 2020. http://hdl.handle.net/10803/668722.
Повний текст джерелаThis thesis focuses on historical reconstructions in European cinema and its main objective is to define the genealogy of a model of figuration and transmission of history, rooted in modernity and emerging after World War II, persisting in contemporary film and television. This model has main axis images whose mise-en-scene drags the viewer to the time represented, thanks to figuring it as a sensory and dialectical experience that allows the audience to reread the past. The haptic and dialectical approach to the past allows to build images that operate as spaces of experience for the viewer, generating a temporality that evokes the experience of historical time, but also generates a new vision of the present. Through this look at history and its cinematic reconstructions we explore the temporalities that are generated, both in historical writing through images and in its encounter with the audience.
Wahrlich, Philip Shane. "Systematic and statistical uncertainties in cosmic ray arrival direction reconstruction." Thesis, 2013. http://hdl.handle.net/2440/82150.
Повний текст джерелаThesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, 2013
Richardt, Carsten [Verfasser]. "Acoustic particle detection : direction and source location reconstruction techniques = Akustische Teilchendetektion / vorgelegt von Carsten Richardt." 2010. http://d-nb.info/1006640649/34.
Повний текст джерелаHuang, Guan-Ming, and 黃冠銘. "Reconstruction of 3D Building Block Models by Using the Driving Direction based on Stereo Camera." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/72269830346863609858.
Повний текст джерела國立中正大學
電機工程研究所
104
Because of advancing with satellite technology in recent years, a lot of GPS techniques are also such rapid development and popularity that every car set up the GPS. However, most of the contents are based on 2D street maps or 3D graphic only in some importance scenes like viaducts and so on. These scenes are produced based on manual mode, not only much time-consuming but the quality of watching also is less realness. In order to impress users more realness, the GPS on image based has come to be the most trends which we take the pictures at the real scenes using them in the reconstruction techniques on image based. But GPS on image based needs a lot of manpower now, it build the models first, and then map the texture of buildings on the models. We propose a method which direction of shooting are the same as the driving direction with stereo camera. Using it reconstruct models of the 3D building cuboid and the most importance part is getting the orientation, length width, and height. First, we calibrate the stereo camera include intrinsic matrix, extrinsic matrix and fisheye distortion parameter. And then, after using Hough Transform to get the vanishing point of the buildings with parallel lines in the image, we can estimate the orientation of the cuboid models. We use the features on the skyline to get the lengths of the 3D cuboid models in our system. Finally, we use the particle filter to refine the 3d coordinates. Finally, we provide users surfing and navigation the 3D Buildings through Virtual Reality techniques to impress users.
Lin, Ya-Ju, and 林雅茹. "Development of Volume-to-Volume True-Direction Flux Reconstruction Scheme in the Quiet Direct Simulation Method for Euler Equation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/93207408877283601301.
Повний текст джерела國立交通大學
機械工程系所
101
A particle-based quiet direct simulation (QDS) method [Albright et al., 2002] was invented to solve the inviscid Euler equation, in which the Maxwell-Boltzmann velocity distribution is enforced through the use of Gauss-Hermite quadrature integration without using any random number. It is a very fast Euler equation solver, which is deterministic with large dynamic range of flow properties like most conventional CFD methods, employs true-direction conservative fluxes for faithfully mimicking real flow motion, is highly localized (a small stencil) for easier parallelization and requires very low memory because the discrete velocities can be re-used in each cell. However, it is numerically very diffusive and has been extended to a nearly second-order numerical scheme by Smith et al. [2009] without really considering true-direction flux reconstruction. Thus, we intend to further address this problem from both numerical and theoretical viewpoints in this thesis. In the numerical part, a true-direction flux reconstruction of the second-order quiet direct simulation (QDS) as an equivalent Euler equation solver, called QDS-N2, is presented. Because of the true-directional nature of QDS, where volume-to-volume (true direction) fluxes are computed, as opposed to fluxes at cell interfaces as employed by traditional finite volume schemes, a volumetric reconstruction is required to reach a totally true-direction scheme. The conserved quantities are permitted to vary (according to a polynomial expression) across all simulated dimensions. Prior to the flux computation, QDS particles are introduced using properties based on weighted moments taken over the polynomial reconstruction of the conserved variables such as mass, momentum and energy. The resulting flux expressions are shown to exactly reproduce the existing second-order extension for a one-dimensional flow, while providing a means for true multi-dimension reconstruction.The new reconstruction is demonstrated in several verification studies. These include several two-dimensional test cases such as shock bubble interaction problem, an Euler-four-shock interaction, Euler-four-contact interaction, Mach 3 facing over a forward step, and the advection of a vortical disturbance. These results are presented, and the increased computational time and the effect of higher-order extension are discussed. The results show that the proposed multi-dimensional reconstruction provides a significant increase in the accuracy of the solution as compared to the previously developed QDS-2N method. We show that, despite the increase in the computational expense, the computational speed of the proposed QDS-N2 method is several times higher than that of the previously proposed QDS-2N method for a fixed degree of numerical accuracy, at least, for the test problem of the advection of vertical disturbances. As mentioned earlier, QDS method is intrinsically a highly localized numerical scheme, which makes it highly suitable for parallel computing on distributed-memory cluster machines using domain decomposition. With parallel implementation, an extension to three-dimensional QDS method is also demonstrated. The results show that the parallel efficiency, based on a strong scaling study, for a large-scale problem using 0.5, 2, and 12.5 million cells can reach up to 75%, 68.5%, and 65.5% with 256 processors respectively. In addition, the parallel efficiency, based on a weak scaling study, for a shock bubble interaction is 1.2, which the ideal efficiency is 1.0, up to 49 processors for 20,000 cells per processor. Note all the parallel performance tests were performed at the APLS cluster of National Center for High-Performance Computing, Taiwan. In the theoretical part, we have derived the analytical expressions of all the fluxes related to mass, momentum and energy in the two-dimensional QDS-N2 and QDS-2N methods respectively. Comparisons are made systematically between the corresponding fluxes in the two methods by varying flow properties. Results show that a large discrepancy of fluxes between these two methods occurs in the ranges of low density, low temperature, and high velocity.It is also interesting to learn that this range of gas flow often corresponds to an expansion wave region. Moreover, the fluxes using both methods are similar horizontal and vertical directions (x and y-direction), while large discrepancy is found in the fluxes going to the diagonal direction.With this observation, we can evaluate the accuracy of QDS-2Nmethod as compared to QDS-N2 method in the flow field, which may be important in deciding which method to be used for different flow problems. The major findings of the research with the recommendations for future study are summarized at the end of the thesis.
Yu, Lu [Verfasser]. "Consequences of the globalization and the entry to the WTO on the reform of the Chinese financial sector : direction and impacts of reconstruction in the bank industry / vorgelegt von Yu Lu." 2005. http://d-nb.info/975477609/34.
Повний текст джерела林書賢. "Face Reconstruction from Multiple Images with Different Viewing Directions." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/24562173066234941663.
Повний текст джерела國立臺灣大學
資訊工程學研究所
90
A new method for human face reconstruction is developed in this work, which deforms a 3D generic face model based on multiple images taken from different viewing directions. The developed method consists of two stages. In the first stage, 3D positions of some features of the initial face model are reconstructed via a camera-pose-estimation technique under orthogonal projection. By applying an interpolation technique, the face model is deformed from the initial face model to fit the computed 3D feature points. In the second stage, an energy function is formulated to measure differences between the image contours and the projected contours of the 3D face model. The optimization process is performed in frequency domain for achieving global and smooth adjustment. With the developed technique, realistic face models can be generated.
Chen, Huang-Jie, and 陳煌杰. "A Facial Model Reconstruction with Images Acquired from Multiple Directions." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/529zp3.
Повний текст джерела國立臺北科技大學
土木與防災研究所
99
As the prompt development of IT technology, plus the continuous enhancement of camera resolution, utilizing photogrammetry to establish highly precise 3-dimensional (3D) models becomes more and more popular. Photogrammetry can also provide visible multi-angle measurement and display. Compare with traditional measurement methodology, photogrammetry is a great time saver. However, for different fields of photogrammetry applications such as bridge monitoring, slope monitoring, and plastic surgery … etc, the precision requirements of 3D models are not quite the same. The 3D-models precision requirements for the plastic surgery and surgical operation should at least up to millimeter level. Domestic literature indicates that object-space matching related studies have already successfully established facial 3D models with the precision up to less than 1mm. However, these studies lack of applying ear 3D models to the facial models which will cause failure to establish overall facial landmark. This is the enhance focus for this study. There are 5 parts in this study: (1) change from the past only taking straight facial photos with multi-viewing angles approach; (2) add in the concept of camera lens distortion difference to object-space matching, establish overall facial 3D model with left-side, middle, and right-side view; (3) by adding in two methodologies (product point cloud model set triangular mesh & apply orthophoto and adding in point cloud model to the RGB data) to display facial models; (4) utilizing 2D photogrammetry and 3D model measurement methodology to conduct 10 facial symbol landmarks measurements, and performance the comparison of the precision; (5) in the end of the experiment, will apply this facial symbol landmark 3D measurement to 30 grown ups (aged between 19-30) to establish statistics. The measuring results like overall facial line length and angles can be provided for further analysis and reference in the future.
Lo, Tzu-Hsuan, and 羅子軒. "A Bi-directional Visual Stereo Interface for 3-D Reconstruction." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/34870513324790436217.
Повний текст джерела國立暨南國際大學
資訊工程學系
90
Reconstruction of the 3-D shape of an object with high fidelity using stereo vision is always an important research topic in the field of computer vision. Human can effortlessly match the stereo correspondences of a point but are not skilful to accurately determine the 3-D coordinates of the point. On the other hand, a machine vision system can easily determine the 3-D coordinates of a point given correct stereo correspondences and the calibration parameters, but there is no efficient algorithm for determining stereo correspondences robustly. Because an interactive 3-D reconstruction system possesses both the merits of the human vision and the machine vision, stereo correspondences can be robustly estimated under the guidance of the operator yielding accurate 3-D reconstruction results. Therefore, lots of research groups have focused on developing interactive 3-D reconstruction system. However, the current human-computer interface is designed for word processing and 2-D graphics, thus is not suitable for interactive 3-D reconstruction. In this thesis, a bi-directional visual stereo interface for accessing the stereo matching results from a human brain is proposed. The stereo interface consists of a binocular gaze tracking system and a stereo display. The binocular gaze tracker comprises a binocular pupil tracker and a head tracker. A robust algorithm is developed to extract the pupil centers of user’s eyes in video rate (30 Hz). The estimated pupil positions plus the estimated head position can be used to provide 3-D lines of sight of user’s both eyes. While the operator stares at a point shown on the stereo display, the binocular gaze tracker records the stereo correspondences for guiding the interactive system to reconstruct 3-D information contained in the stereo images. Experimental results show that the proposed interface is very promising.
TÍKOVÁ, Stanislava. "Návrh rekonstrukce a modernizace polní cesty s využitím technologického zařízení pro aplikaci Gloritu." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-50480.
Повний текст джерелаKollmeier, Jost M. "Multi-Directional Phase-Contrast Flow MRI in Real Time." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-155C-D.
Повний текст джерела