Download or read book Avancements Dans L estimation de Pose Et la Reconstruction 3D de Sc nes 2 Et 3 Vues written by Laura Fernandez Julia and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of cameras and images has been a prominent subject since the beginning of computer vision, one of the main focus being the pose estimation and 3D reconstruction. The goal of this thesis is to tackle and study some specific problems and methods of the structure-from-motion pipeline in order to provide improvements in accuracy, broad studies to comprehend the advantages and disadvantages of the state-of-the-art models and useful implementations made available to the public. More specifically, we center our attention to stereo pairs and triplets of images and discuss some of the methods and models able to provide pose estimation and 3D reconstruction of the scene.First, we address the depth estimation task for stereo pairs using block-matching. This approach implicitly assumes that all pixels in the patch have the same depth producing the common artifact known as the ``foreground fattening effect''. In order to find a more appropriate support, Yoon and Kweon introduced the use of weights based on color similarity and spatial distance, analogous to those used in the bilateral filter. We present the theory of this method and the implementation we have developed with some improvements. We discuss some variants of the method and analyze its parameters and performance.Secondly, we consider the addition of a third view and study the trifocal tensor, which describes the geometric constraints linking the three views. We explore the advantages offered by this operator in the pose estimation task of a triplet of cameras as opposed to computing the relative poses pair by pair using the fundamental matrix. In addition, we present a study and implementation of several parameterizations of the tensor. We show that the initial improvement in accuracy of the trifocal tensor is not enough to have a remarkable impact on the pose estimation after bundle adjustment and that using the fundamental matrix with image triplets remains relevant.Finally, we propose using a different projection model than the pinhole camera for the pose estimation of perspective cameras. We present a method based on the matrix factorization due to Tomasi and Kanade that relies on the orthographic projection. This method can be used in configurations where other methods fail, in particular, when using cameras with long focal length lenses. The performance of our implementation of this method is compared to that given by the perspective-based methods, we consider that the accuracy achieved and its robustness make it worth considering in any SfM procedure.
Download or read book Applying Multiframe Reconstruction to Pose Estimation written by University of Massachusetts at Amherst. Department of Computer Science and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 3 D Reconstruction of Urban Scenes from Sequences of Images written by Institut National de Recherche en Informatique et en Automatique and published by . This book was released on 1995 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multi scale Feature Preserving Smoothing of Images and Volumes on GPU written by Nassim Jibai and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les images et données volumiques sont devenues importantes dans notre vie quotidienne que ce soit sur le plan artistique, culturel, ou scientifique. Les données volumiques ont un intérêt important dans l'imagerie médicale, l'ingénierie, et l'analyse du patrimoine culturel. Ils sont créées en utilisant la reconstruction tomographique, une technique qui combine une large série de scans 2D capturés de plusieur points de vue. Chaque scan 2D est obtenu par des methodes de rayonnement : Rayons X pour les scanners CT, ondes radiofréquences pour les IRM, annihilation électron-positron pour les PET scans, etc. L'acquisition des images et données volumique est influencée par le bruit provoqué par différents facteurs. Le bruit dans les images peut être causée par un manque d'éclairage, des défauts électroniques, faible dose de rayonnement, et un mauvais positionnement de l'outil ou de l'objet. Le bruit dans les données volumique peut aussi provenir d'une variété de sources : le nombre limité de points de vue, le manque de sensibilité dans les capteurs, des contrastes élevé, les algorithmes de reconstruction employés, etc. L'acquisition de données non bruitée est iréalisable. Alors, il est souhaitable de réduire ou d'éliminer le bruit le plus tôt possible dans le pipeline. La suppression du bruit tout en préservant les caractéristiques fortes d'une image ou d'un objet volumique reste une tâche difficile. Nous proposons une méthode multi-échelle pour lisser des images 2D et des données tomographiques 3D tout en préservant les caractéristiques à l'échelle spécifiée. Notre algorithme est contrôlé par un seul paramètre - la taille des caractéristiques qui doivent être préservées. Toute variation qui est plus petite que l'échelle spécifiée est traitée comme bruit et lissée, tandis que les discontinuités telles que des coins, des bords et des détails à plus grande échelle sont conservés. Nous démontrons les données lissées produites par notre algorithme permettent d'obtenir des images nettes et des iso-surfaces plus propres. Nous comparons nos résultats avec ceux des methodes précédentes. Notre méthode est inspirée par la diffusion anisotrope. Nous calculons nos tenseurs de diffusion à partir des histogrammes continues locaux de gradients autour de chaque pixel dans les images et autour de chaque voxel dans des volumes. Comme notre méthode de lissage fonctionne entièrement sur GPU, il est extrêmement rapide.
Download or read book Combining geometric and appearance priors for pose recovery written by Eduard Seradel Domingo and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Estimar la pose (rotació i translació) de la càmera a partir dels punts d'interés de l'escena 3D i punts de la imatge 2D és un problema ben resolt en el cas que es coneguin les correspondències entre ells. No obstant, quan aquestes correspondències no poden ser establertes a priori, s'han d'anar calculant al mateix temps que la posició de la càmera. Aquest és un problema que ha estat abordat d'una manera interessant per l'algoritme BlindPnP [27]. Aquest mètode és basa en el fet que a la pràctica, podem disposar d'alguns priors sobre la pose de la càmera. Es modelen per mitjà d'un model de suma de gaussianes que es va refinant progressivament, al mateix temps que s'hipotetitzen noves correspondències. Així, es redueix ràpidament el nombre de correspondències materials per a cada punt 3D i ens permet explorar l'espai de pose d'una manera prou eficient. Els problemes apareixen quan el nombre de punts d'interés de l'escena és elevat, tal i com pot succeir si es pretén aplicar l'algoritme en models de grans ciutats o d'escenes 3D tretes de grans bases de dades (internet). En aquest projecte demostrem que introduint la informació de la textura sobre el model i combinant priors tant geomètrics com d'aparença, és possible millorar el cost computacional del BlindPnP, aconseguint uns resultats similars. A més, si amb el BlindPnP podíem utilitzar models 3D fins a M = 100 punts, ara aconseguim treballar amb xifres de M' = 100000 punts, una millora de tres ordres de magnitud. Ens permetem doncs, imaginar l'aplicació de l'algoritme en escenes reals.
Download or read book Strengthening Forensic Science in the United States written by National Research Council and published by National Academies Press. This book was released on 2009-07-29 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scores of talented and dedicated people serve the forensic science community, performing vitally important work. However, they are often constrained by lack of adequate resources, sound policies, and national support. It is clear that change and advancements, both systematic and scientific, are needed in a number of forensic science disciplines to ensure the reliability of work, establish enforceable standards, and promote best practices with consistent application. Strengthening Forensic Science in the United States: A Path Forward provides a detailed plan for addressing these needs and suggests the creation of a new government entity, the National Institute of Forensic Science, to establish and enforce standards within the forensic science community. The benefits of improving and regulating the forensic science disciplines are clear: assisting law enforcement officials, enhancing homeland security, and reducing the risk of wrongful conviction and exoneration. Strengthening Forensic Science in the United States gives a full account of what is needed to advance the forensic science disciplines, including upgrading of systems and organizational structures, better training, widespread adoption of uniform and enforceable best practices, and mandatory certification and accreditation programs. While this book provides an essential call-to-action for congress and policy makers, it also serves as a vital tool for law enforcement agencies, criminal prosecutors and attorneys, and forensic science educators.
Download or read book Reconstruction 3d de sc nes urbaines written by Sourimant-G and published by Omn.Univ.Europ.. This book was released on 2018-02-28 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: La probl matique abord e dans ce document est celle de la reconstruction en 3D de zones urbaines dans un contexte tr s peu contraint, par fusion de donn es GPS, SIG et vid o. L'objectif est de raffiner des mod les 3D simples et g or f renc s de b timents, extraits d'une base SIG, en les mettant en correspondance avec des vid os acquises au sol, la position de la cam ra tant estim e par GPS. La fusion des vid os et des mod les 3D correspondants est calcul e par une analyse contextuelle des images acquises, associ e un asservissement visuel virtuel robuste. Nous obtenons ainsi une information de pose de la cam ra pour chaque image en entr e. Nous pr sentons galement une m thode d'extration des textures de fa ade des b timents la fois robuste aux probl mes d'occultation, de r solution spatiale des images ou aux sp cularit s pr sentes dans les vid os. Enfin, nous pr sentons une tude pr liminaire sur l'extraction des d tails g om triques de chaque fa ade. Un calcul de disparit par coupe de graphe ou flot optique est effectu e dans l'espace texture. Les micro-structures des fa ades peuvent alors tre retrouv es en utilisant ces cartes de disparit .
Download or read book 3D Echocardiography written by Takahiro Shiota and published by CRC Press. This book was released on 2020-12-29 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the second edition of this volume, 3D echocardiography has penetrated the clinical arena and become an indispensable tool for patient care. The previous edition, which was highly commended at the British Medical Book Awards, has been updated with recent publications and improved images. This third edition has added important new topics such as 3D Printing, Surgical and Transcatheter Management, Artificial Valves, and Infective Endocarditis. The book begins by describing the principles of 3D echocardiography, then proceeds to discuss its application to the imaging of • Left and Right Ventricle, Stress Echocardiography • Left Atrium, Hypertrophic Cardiomyopathy • Mitral Regurgitation with Surgical and Nonsurgical Procedures • Mitral Stenosis and Percutaneous Mitral Valvuloplasty • Aortic Stenosis with TAVI / TAVR • Aortic and Tricuspid Regurgitation • Adult Congenital Heart Disease, Aorta • Speckle Tracking, Cardiac Masses, Atrial Fibrillation KEY FEATURES In-depth clinical experiences of the use of 3D/2D echo by world experts Latest findings to demonstrate clinical values of 3D over 2D echo One-click view of 263 innovative videos and 352 high-resolution 3D/2D color images in a supplemental eBook.
Download or read book Reeb Graph Based 3D Shape Modeling and Applications written by Julien Tierny and published by . This book was released on 2008 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Avec le développement récent des technologies 3D, les formes 3D sont devenues un type de données multimedia interactives de première importance. Leur représentation la plus courante, le maillage de polygones, souffre cependant de grande variabilité face à des transformations canoniques préservant la forme. Il est donc nécessaire de concevoir des techniques de modélisation intrinsèque de forme. Dans cette thèse, nous explorons la modélisation topologique par l'étude de structures basées sur les graphes de Reeb. En particulier, nous introduisons une nouvelle abstraction de forme, appelée squelette topologique avancé, qui permet non seulement l'étude de l'évolution topologique des lignes de niveau de fonctions de Morse mais aussi l'étude de leur évolution géométrique. Nous démontrons l'utilité de cette représentation intrinsèque de forme dans trois problèmes de recherche liés à l'Informatique Graphique et à la Vision par Ordinateur.Tout d'abord, nous introduisons la notion de calcul géométrique sur les graphes de Reeb pour le calcul automatique et stable de squelettes de contrôle pour la manipulation interactive de forme. Ensuite, en introduisant les notions de cartes de Reeb et de motifs de Reeb, nous proposons une nouvelle méthode pour l'estimation de similarité partielle entre formes 3D. Nous montrons que cette approche dépasse les méthodes participant au concours international de reconnaissance de forme 2007 (SHREC 2007) par un gain de 14%. Enfin, nous présentons deux techniques permettant de fournir une décomposition fonctionnelle d'une forme 3D, à la fois en considérant des heuristiques issues de la théorie de la perception humaine et des données 3D variant dans le temps.
Download or read book Traitement de s quences d images pour l estimation jointe de la structure et du mouvement written by Martial Sanfourche and published by . This book was released on 2005 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: We address urban scene 3D reconstruction from partially calibrated side looking aerial image sequences. We proceed in two steps. The first step corresponds to an auto-calibration step. Camera motion parameters and 3D position of some scene points are jointly refined by bundle adjustment. In the second step, a multi frame dense matching method is used to obtain a dense 3D reconstruction in the form of digital surface model. Matching lays on a global pixelwise criterion with explicit account for occlusion effects and a spatial regularisation with a discontinuity preserving L1-norm penalization term. Optimisation is achieved thanks to an efficient graph-based algorithm. In order to improve the resolution of the reconstruction, temporally close images are used to generate best resolution images by a super-resolution process. Then super-resolved images are matched. We present results and evaluation on synthetic and real image sequences.
Download or read book Three dimensional Echocardiography written by Navin Chandar Nanda and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1992 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biomass and Stem Volume Equations for Tree Species in Europe written by Dimitris Zianis and published by . This book was released on 2005 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of stem volume and biomass equations for tree species growing in Europe is presented. The mathematical forms of the empirical models, the associated statistical parameters and information about the size of the trees and the country of origin were collated from scientific articles and from technical reports. The collected information provides a basic tool for estimation of carbon stocks and nutrient balance of forest ecosystems across Europe as well as for validation of theoretical models of biomass allocation.
Download or read book Molecular Photofitting written by Tony Frudakis Ph.D. and published by Elsevier. This book was released on 2010-07-19 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the field of forensics, there is a critical need for genetic tests that can function in a predictive or inferential sense, before suspects have been identified, and/or for crimes for which DNA evidence exists but eye-witnesses do not. Molecular Photofitting fills this need by describing the process of generating a physical description of an individual from the analysis of his or her DNA. The molecular photofitting process has been used to assist with the identification of remains and to guide criminal investigations toward certain individuals within the sphere of prior suspects. Molecular Photofitting provides an accessible roadmap for both the forensic scientist hoping to make use of the new tests becoming available, and for the human genetic researcher working to discover the panels of markers that comprise these tests. By implementing population structure as a practical forensics and clinical genomics tool, Molecular Photofitting serves to redefine the way science and history look at ancestry and genetics, and shows how these tools can be used to maximize the efficacy of our criminal justice system. - Explains how physical descriptions of individuals can be generated using only their DNA - Contains case studies that show how this new forensic technology is used in practical application - Includes over 100 diagrams, tables, and photos to illustrate and outline complex concepts
Download or read book Digital Breast Tomosynthesis written by Alberto Tagliafico and published by Springer. This book was released on 2016-05-03 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive description of the screening and clinical applications of digital breast tomosynthesis (DBT) and offers straightforward, clear guidance on use of the technique. Informative clinical cases are presented to illustrate how to take advantage of DBT in clinical practice. The importance of DBT as a diagnostic tool for both screening and diagnosis is increasing rapidly. DBT improves upon mammography by depicting breast tissue on a video clip made of cross‐sectional images reconstructed in correspondence with their mammographic planes of acquisition. DBT results in markedly reduced summation of overlapping breast tissue and offers the potential to improve mammographic breast cancer surveillance and diagnosis. This book will be an excellent practical teaching guide for beginners and a useful reference for more experienced radiologists.
Download or read book Global Economic Prospects June 2021 written by World Bank and published by World Bank Publications. This book was released on 2021-08-03 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world economy is experiencing a very strong but uneven recovery, with many emerging market and developing economies facing obstacles to vaccination. The global outlook remains uncertain, with major risks around the path of the pandemic and the possibility of financial stress amid large debt loads. Policy makers face a difficult balancing act as they seek to nurture the recovery while safeguarding price stability and fiscal sustainability. A comprehensive set of policies will be required to promote a strong recovery that mitigates inequality and enhances environmental sustainability, ultimately putting economies on a path of green, resilient, and inclusive development. Prominent among the necessary policies are efforts to lower trade costs so that trade can once again become a robust engine of growth. This year marks the 30th anniversary of the Global Economic Prospects. The Global Economic Prospects is a World Bank Group Flagship Report that examines global economic developments and prospects, with a special focus on emerging market and developing economies, on a semiannual basis (in January and June). Each edition includes analytical pieces on topical policy challenges faced by these economies.
Download or read book Bone Tissue Engineering written by Jeffrey O. Hollinger and published by CRC Press. This book was released on 2004-10-14 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focusing on bone biology, Bone Tissue Engineering integrates basic sciences with tissue engineering. It includes contributions from world-renowned researchers and clinicians who discuss key topics such as different models and approaches to bone tissue engineering, as well as exciting clinical applications for patients. Divided into four sections, t
