Examinando por Materia "PROCESAMIENTO DE IMÁGENES"
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Ítem 2D Shape similarity as a complement for Voronoi-Delone methods in shape reconstruction(Elsevier, 2005) Ruíz S., Óscar E.; Cadavid, Carlos A.; Granados, Miguel; Peña, Sebastián; Vásquez, Eliana; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEIn surface reconstruction from planar slices it is necessary to build surfaces between corresponding 2D regions in consecutive levels -- The problem has been traditionally attacked with (i) direct reconstruction based on local geometric proximity between the regions, and (ii) classification of topological events between the slices, which control the evolution of the cross cuts -- These approaches have been separately applied with mixed success -- In the case (i), the results may be surfaces with over-stretched or unnatural branches, resulting from a local contour proximity which does not correspond to global similarity between regions -- In (ii), the consequences from topological events upon the actual surface realization have not been drawn -- In this paper an integration of (i) and (ii) is presented, which uses a criteria of similarity between composed 2D regions in consecutive slices to: (a) decide if a surface should actually relate those regions, (b) identify the topological transitions between levels and (c) construct the local surface for the related regions -- The method implemented hinders over-stretched and unnatural branches, therefore rendering a surface which adjusts to geometrically-sound topological events -- This is a good alternative when the surface reconstructed needs to be topologically faithful (for example in flow simulation) in addition to represent the a rough geometrical space (for example in radiation planning)Ítem Automatic Tools for Data Diagnostic and Correction in Aerophotogrametry(INGEGRAF, 1999) Ruíz Salguero, Óscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEEn Aerofotogrametría, el proceso de restitución (paso de imagen a formato electrónico vectorizado) es realizado por un operador humano, con asistencia de hardware y Software especializado -- Dicho proceso implica la traducción de accidentes geográficos, detalles topográficos, etc., la cual conlleva errores tanto geométricos (precisión) como topológicos (conectividad) de los datos digitales vectorizados -- Adicionalmente, aun si la vectorizacion es perfecta, los editores en etapas subsecuentes deben realizar tareas repetitivas: formateo, marcado, ajuste de convenciones, etc., que por el tamaño de los archivos de datos se hacen prolongadas y propensas al error -- Tanto los procesos de corrección como de formateo y marcado requieren además la ejecución de entradas / salidas con el usuario en el computador, proceso que es particularmente lento -- Esta investigación presenta el desarrollo de herramientas automáticas de (i) detección y corrección de errores comunes en los planos restituidos, (ii) partición y re-agrupación inteligentes de planos grandes, y (iii) formateo y marcado automático -- El desarrollo de software se hace usando el standard AIS (Application Interface Specification), lo que lo hace portable a los modeladores cuya interface AIS haya sido implementada -- El proyecto se desarrolla para la firma AeroEstudios LTDA de Colombia, la cual lo ha incorporado a sus herramientas de procesamiento de información digitalÍtem Computational aberration correction in optical coherence tomography with phase-unstable systems(Universidad EAFIT, 2020) Ruiz Lopera, Sebastián; Restrepo Gómez, RenéOptical coherence tomography (OCT) is an imaging technique widely use in medicine. OCT is an optical technique, therefore it is prone to optical aberrations that degrade image quality, making it difficult to visualize fine structures with high resolution.This work presents SHARP, a computational technique for correction of aberrations in OCT, that is compatible with most standard systems, and we present results in eye, airway and skin imagingÍtem Coupling Terrain and Building Database Information for Ray-Tracing Applications(2003) Fontán, F.P.; Ruíz S., O.E.; Peña, S.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEIn this paper a methodology for the combination and integration into a single data base of terrain and building data is presented -- This study is justified if ray-tracing techniques are to be used in propagation and channel modeling studies -- Usually terrain is available in grid or elevation form while building information is normally facet-oriented -- Ray-tracing (RT) techniques deal with flat facets and straight edges, if possible in triangular format -- To allow the use of RT on urban areas over irregular terrain a common format made up of facets and edges is therefore needed -- In this article, the procedure to accomplish this data homogeneity is presented -- It is assumed that terrain data is available in two formats: a) grid elevation and b) contour or iso-altitude lines -- Building data is assumed available in plant, polygonal planar contour form, a primitive and yet widely used format which is yet to be transformed into 3D entities -- The geometric modeling of joint terrain and building data is further difficuledt because union of surface objects (even after achieving a unified format) is undefined from the point of view of 3D boolean operationsÍtem DC term filtering techniques in digital holography(SPIE, 2004-10-21) Velásquez-Prieto, Daniel; García Sucerquia, Jorge Iván; Herrera Ramírez, Jorge Alexis; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaIn numerical hologram reconstruction like in optical holography, there exist different diffraction orders, which many times produce difficulties for the image visualizations. In numerical reconstruction, the filtering of the DC term, or zero order diffraction, provides an improved utilization of the dynamic range of the visualization systems, which is needed for the right displaying purposes of reconstructed images. In the case of the in-line set-ups, the zero diffraction order has even more devastating effects because it does not allow reconstructing the images itself as in Gabor's holograms, so it is necessary to attempt a filtering of this DC term. In this work is shown a qualitative assessment of different techniques of DC term filtering applied to numerical reconstruction of Fresnel's holograms recorded by means of off-line set-ups.Ítem Desarrollo de un algoritmo de corte de mallas tridimensionales en ambientes virtuales con aplicaciones en simuladores quirúrgicos(Universidad EAFIT, 2009) Peniche González, Amaury Andrés; Díaz León, Christian AndrésÍtem Edge and corner identification for tracking the line of sight(Fondo Editorial EAFIT, 2005) Orozco, María S.; Ruíz, Óscar E.; Jasnoch, Uwe; Kretschmer, Ursula; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article presents an edge-corner detector, implemented in the realm of the GEIST project (an Computer Aided Touristic Information System) to extract the information of straight edges and their intersections (image corners) from camera-captured (real world) and computer-generated images (from the database of Historical Monuments, using observer position and orientation data) -- Camera and computer-generated images are processed for reduction of detail, skeletonization and corner-edge detection -- The corners surviving the detection and skeletonization process from both images are treated as landmarks and fed to a matching algorithm, which estimates the sampling errors which usually contaminate GPS and pose tracking data (fed to the computer-image generatator) -- In this manner, a closed loop control is implemented, by which the system converges to exact determination of position and orientation of an observer traversing a historical scenario (in this case the city of Heidelberg) -- With this exact position and orientation, in the GEIST project other modules are able to project history tales on the view field of the observer, which have the exact intended scenario (the real image seen by the observer) -- In this way, the tourist “sees” tales developing in actual, material historical sites of the city -- To achieve these goals this article presents the modification and articulation of algorithms such as the Canny Edge Detector, SUSAN Corner Detector, 1-D and 2-D filters, etceteraÍtem Face Reconstruction with structured light(SciTePress, 2011-03) Congote, John; Barandiaran, Iñigo; Barandiaran, Javier; Nieto, Marcos; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article presents a methodology for reconstruction of 3D faces which is based on stereoscopic images of the scene using active and passive surface reconstruction -- A sequence of gray patterns is generated, which are projected onto the scene and their projection recorded by a pair of stereo cameras -- The images are rectified to make coincident their epipolar planes and so to generate a stereo map of the scene -- An algorithm for stereo matching is applied, whose result is a bijective mapping between subsets of the pixels of the images -- A particular connected subset of the images (e.g. the face) is selected by a segmentation algorithm -- The stereo mapping is applied to such a subset and enables the triangulation of the two image readings therefore rendering the (x;y; z) points of the face, which in turn allow the reconstruction of the triangular mesh of the face -- Since the surface might have holes, bilateral filters are applied to have the holes filled -- The algorithms are tested in real conditions and we evaluate their performance with virtual datasets -- Our results show a good reconstruction of the faces and an improvement of the results of passive systemsÍtem Fitting of Analytic Surfaces to Noisy Point Clouds(Scientific Research Publishing, 2013-04) Ruíz, Óscar; Arroyave, Santiago; Acosta, Diego; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEFitting -continuous or superior surfaces to a set of points sampled on a 2-manifold is central to reverse engi- neering, computer aided geometric modeling, entertaining, modeling of art heritage, etc -- This article addresses the fit- ting of analytic (ellipsoid, cones, cylinders) surfaces in general position in -- Currently, the state of the art presents limitations in 1) automatically finding an initial guess for the analytic surface F sought, and 2) economically estimat- ing the geometric distance between a point of and the analytic surface SF -- These issues are central in estimating an analytic surface which minimizes its accumulated distances to the point set -- In response to this situation, this article presents and tests novel user-independent strategies for addressing aspects 1) and 2) above, for cylinders, cones and ellipsoids -- A conjecture for the calculation of the distance point-ellipsoid is also proposed -- Our strategies produce good initial guesses for F and fast fitting error estimation for F, leading to an agile and robust optimization algorithm -- Ongoing work addresses the fitting of free-form parametric surfaces to SÍtem Formación y restauración de imagen en tomografía óptica de coherencia mediante posprocesamiento(Universidad EAFIT, 2017) Cuartas Vélez, Carlos Alfredo; Restrepo Gómez, René; Uribe Patarroyo, NéstorÍtem Geometry and topology extraction and visualization from scalar and vector fields(Universidad EAFIT, 2013) Congote Calle, John Edgar; Ruíz Salguero, Óscar Eduardo; Posada, Jorge LeónÍtem Journal Article on Computational Geometry Application in Parametric Modeling(Universidad EAFIT, 2022) Vélez Sanín, Samuel; Correa Panesso, Jorge Eduardo; Ruiz Salguero, Oscar Eduardo; Ruiz Salguero, Oscar Eduardo; Correa Panesso, Jorge EduardoDigital modeling of human representations or mannequins is a topic with an ever-increasing interest in research and industrial communities. The possibility to obtain a 3D model approximation of any human in a cost-effective manner presents benefits for applications such as virtual tailoring, garment fitting simulation, human motion modeling, avatar creation, etc. Therefore, special interest is placed on finding methods to obtain such mannequins with minimal information and human interaction.Ítem Marching cubes in an unsigned distance field for surface reconstruction from unorganized point sets(2010) Congote, John; Moreno, Aitor; Barandiaran, Iñigo; Barandiaran, Javier; Posada, Jorge; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAESurface reconstruction from unorganized point set is a common problem in computer graphics -- Generation of the signed distance field from the point set is a common methodology for the surface reconstruction -- The reconstruction of implicit surfaces is made with the algorithm of marching cubes, but the distance field of a point set can not be processed with marching cubes because the unsigned nature of the distance -- We propose an extension to the marching cubes algorithm allowing the reconstruction of 0-level iso-surfaces in an unsigned distance field -- We calculate more information inside each cell of the marching cubes lattice and then we extract the intersection points of the surface within the cell then we identify the marching cubes case for the triangulation -- Our algorithm generates good surfaces but the presence of ambiguities in the case selection generates some topological mistakesÍtem MEDX3DOM: MEDX3D for X3DOM(ACM, 2012-08) Congote, John; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEWe present an implementation of MEDX3DOM a MEDX3D standard implemented into the X3DOM framework -- We present the report of a work in progress of the implementation identifying the critical sections to be migrated into the new architecture, and possible extensions of the standard on the Web environment -- Results for the early implementation are shown, where the visualization of medical datasets with advanced direct volume rendering algorithms are obtained under the X3DOM architecture with interactive frame rates and good image quality -- An example of the HTML5/X3DOM document is presented with futureÍtem Modelado 4D y monitoreo de productividad IP en proyectos de construcción(Universidad EAFIT, 2015) Aguilar Lopera, Gabriel; Botero Botero, Luis FernandoEl presente trabajo describe los procedimientos y resultados de la profundización en implementación de realidad virtual y las TIC en procesos constructivos de un proyecto real, por medio de herramientas de modelado BIM y monitoreo con cámaras IP, que se realizó con el propósito de explorar los resultados de la aplicación de estas tecnologías en un proyecto privado de vivienda, como ayudas en los procesos de las fases de planificación y ejecución de obra; para su desarrollo se realizó un proyecto piloto en el proyecto de vivienda privada Cantagirone Tre Piu, en la ciudad de Medellín, en el cual mediante la realización de modelos 3D y 4D, y empleando el software IDEO para el monitoreo de productividad IP, se pretendió comprobar la hipótesis de que, el modelado 4D y el monitoreo IP ayuda a mejorar los proyectos de construcción en su planificación y ejecución -- Los resultados obtenidos parten de los informes de la supervisión técnica apoyada en la programación de obra, y la adquisición de datos que se obtuvieron del software IDEO durante el proceso de construcción de la estructura -- Como resultado final de la profundización se formula una propuesta de inclusión de modelado BIM 3D y 4D y monitoreo de productividad IP, como herramientas para la mejora de procesos constructivosÍtem Movement in video classification using structured data : Workout videos application(Universidad EAFIT, 2023) Múnera Muñoz, Jonathan Damián; Tabares Betancur, Marta SilviaNowadays, several video movement classification methodologies are based on reading and processing each frame using image classification algorithms. However, it is rare to find approaches using angle distribution over time. This paper proposes video movement classification based on the exercise states calculated from each frame's angles. Different video classification approaches and their respective variables and models were analyzed to achieve this, using unstructured data: images. Besides, structure data as angles from critical joints Armpits, legs, elbows, hips, and torso inclination were calculated directly from workout videos, allowing the implementation of classification models such as the KNN and Decision Trees. The result shows these techniques can achieve similar accuracy, close to 95\%, concerning Neural Networks algorithms, the primary model used in the previously mentioned approaches. Finally, it was possible to conclude that using structured data for movement classification models allows for lower performance costs and computing resources than using unstructured data without compromising the quality of the model.Ítem Phase-difference images by digital holography applied to 3D surface contouring(Academia Colombiana de Ciencias Exactas Físicas y Naturales, 2005-06) Velásquez-Prieto, Daniel; García Sucerquia, Jorge Iván; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThe problem to determine the 3D-contour of objects with all sizes and shapes is a hot topic in diverse fields of optical research and engineering. Through the use of the numerical reconstruction of digital recorded holograms, we propose a technique to evaluate the 3D contour of objects at least four orders of magnitude larger than the optical wavelength. The required 2π-module phase map in any contouring process is obtained by means of phase-difference image of two digital reconstructed holograms. These holograms are interferometric recordings from a still object under different angle illumination. Our proposal is supported on the theoretical analysis of the contouring system, verified by means of numerical results.Ítem Plataforma de simulación de aberraciones ópticas vía implementación de las características de un SLM y reconstrucción de fase usando algoritmos basados en los sensores de Hartmann-Shack(Universidad EAFIT, 2013) Ramírez Cano, Natalia; Restrepo Gómez, René; Ángel Toro, LucianoDada la importancia que hoy día presenta dentro del ámbito de la óptica, la implementación y conocimiento de dispositivos capaces tanto de generar aberraciones ópticas bien caracterizadas como de censarlas, se presenta a lo largo de este trabajo el desarrollo de una interfaz gráfica en MATLAB, que permita simular el funcionamiento tanto de un sensor de frente de onda de Hartamnn-Shack (HS), así como la simulación de dispositivos capaces de modificar frentes de onda como los SLM, adicionando algoritmos de propagación y cálculo de centroides -- Para ello, se implementarán en primer lugar máscaras de fase que generen frentes de onda aberrados a partir de la modulación en fase de moduladores espaciales de luz o SLM, tanto a través de funciones lente de primer orden en representación de las aberraciones constantes, como de fase cuadrática en representación de las aberraciones de bajo orden y adicionalmente como combinaciones lineales de polinomios de Zernike -- Todo lo anterior se simulará teniendo en cuenta las características técnicas de los SLM, como lo son el número de pixeles en x y en y, el tamaño de estos y la curva de calibración de los moduladores espaciales, tanto para una relación lineal como para una relación no lineal -- Posteriormente se simularán las dos propagaciones sufridas por los haces de luz desde el SLM hasta el CCD (dispositivo de carga acoplada), pasando a través de la matriz de multilentes del HS (MLA), a partir de la implementación de algoritmos de propagación de un solo paso, que nos permitirán observar sobre el plano del CDD el mapa de spots necesario para el censado de las superficies -- Continuaremos con la construcción de algoritmos para determinar los centroides de dicho mapa y sus respectivas coordenadas, seguiremos con la implementación de algoritmos de reconstrucción modal empleados por sensores de frente de onda de Hartmann-Shack, y finalmente compararemos el grado de error existente entre las superficies generadas y las superficies censadas a través del cálculo de su error cuadrático medioÍtem A Riemannian Geometry in the q-Exponential Banach Manifold Induced by q-Divergences(Springer Berlin Heidelberg, 2013) Loaiza Ossa, Gabriel Ignacio; Quiceno Echavarría, Héctor Román; Universidad EAFIT. Departamento de Ciencias; Análisis Funcional y AplicacionesFor the family of non-parametric q-exponential statistical models, in a former paper, written by the same authors, a differentiable Banach manifold modelled on Lebesgue spaces of real random variables has been built. In this paper, the geometry induced on this manifold is characterized by q-divergence functionals. This geometry turns out to be a generalization of the geometry given by Fisher information metric and Levi-Civita connections. Moreover, the classical Amari’s α-connections appears as special case of the q −connections ∇ (q). The main result is the expected one, namely the zero curvature of the manifold. Loading... Geometric Science of InformationGeometric Science of Information Look Inside Chapter Metrics Downloads1K Provided by Bookmetrix Other actions Export citation About this Book Reprints and Permissions Add to Papers Share Share this content on Facebook Share this content on Twitter Share this content on LinkedInÍtem A Riemannian geometry in the q-Exponential Banach manifold induced by q-Divergences(Springer Berlin Heidelberg, 2013) Loaiza Ossa, Gabriel Ignacio; Quiceno Echavarría, Héctor Román; Universidad EAFIT. Escuela de Ciencias. Grupo de Investigación Análisis Funcional y Aplicaciones; Gabriel Loaiza (gloaiza@eafit.edu.co); Héctor R. Quiceno (hquiceno@eafit.edu.co); Análisis Funcional y AplicacionesFor the family of non-parametric q-exponential statistical models, in a former paper, written by the same authors, a differentiable Banach manifold modelled on Lebesgue spaces of real random variables has been built -- In this paper, the geometry induced on this manifold is characterized by q-divergence functionals -- This geometry turns out to be a generalization of the geometry given by Fisher information metric and Levi-Civita connections -- Moreover, the classical Amari´s α-connections appears as special case of the q−connections (q) -- The main result is the expected one, namely the zero curvature of the manifold