Examinando por Materia "Cameras"
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Ítem Achieving object persistence in an augmented reality indoor environment(2003-01-01) Gutiérrez, M.D.; Márquez, A.M.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesIn this paper we present a system for achieving object persistence in Augmented Reality Indoors Environments. In AR systems based on the Augmented Reality toolkit without object persistence, virtual objects appear and disappear as the corresponding pattern gets in and out of the user's field of view. Object persistence allows the environment to remember the relative position and orientation of virtual objects, making them appear more stable to the user. We describe object persistence as a series of transformations applied to the objects in a simple indoor environment. We then present the results of a quantitative experiment that shows how interactivity is improved by the use of object persistency.Ítem Design, development, and implementation of a low-cost full-parallax holoprinter(SPIE-INT SOC OPTICAL ENGINEERING, 2018-02-19) Madrid S, A.; D. Velásquez; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaSynthetic holograms have achieved a great impact in a variety of fields like architecture, advertising, army and art, and have proven their importance in advancing the holographic displays as visual communication media. Printing synthetic holograms needs the development of a holographic printer that from a set of 2D images allows to create 3D holographic images of real objects and computer generated objects. With the purpose of developing a holoprinter, we have implemented three related components: i) design and implementation of an optical system for direct writing of hogels, ii) a computational implementation to generate parallax 2D images and finally, iii) the implementation of an opto-mechanical and control system for automatic recording of the synthetic holograms. The three components have been developed under the restricted conditions of our holographic laboratory. In this way, a direct write optical setup was implemented using He-Ne laser, and an optical system for hogel writing with a field of view (FOV) of 60° was designed by using commercial lenses. To generate 2D parallax images, an application was created in the free computer graphics software Blender, applying different camera configurations. And a LabView application was made to automatically control obturation and displacement of the holographic plate. The system developed can record computer generated objects and real objects. Real objects are digitized by using a conventional photographic camera. Reflection full parallax holographic stereograms were recorded on PFG-01 plates and their holographic reconstructions are presented and discussed. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.Ítem Evaluación de impacto de las cámaras de fotodetección en la ciudad de Medellín(Universidad EAFIT, 2014-12-15) Álvarez Restrepo, Juliana; Ospina Londoño, MónicaCon este trabajo se mide el impacto de las cámaras de fotodetección implantadas en el año 2011 en la ciudad de Medellín sobre los accidentes -- Para ello se calculó el estimador de Diferencia en Diferencias, comparando 65 puntos en los cuales se generaron multas electrónicas y otros 95 puntos de control donde nunca se ha instalado un radar de detección electrónica -- Los resultados indican que la magnitud del efecto es negativa, a pesar de que no se contó con la cantidad información de deseada para obtener resultados con mayor contundenciaÍtem High dynamic range imaging method for interferometry(ELSEVIER SCIENCE BV, 2011-01-01) Vargas, J.; Restrepo, R.; Quiroga, J.A.; Belenguer, T.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe demonstrate a method to easily and quickly extend the dynamic range imaging capabilities of the camera in a typical interferometric approach. The camera dynamic range is usually low and limited to 256 gray levels. Also, it is well known that one may have over or under-exposed regions in the interferogram (due to non-uniform illumination) which makes these image regions not reliable. In our proposed method it is not necessary to obtain or use the non-linear camera response curve in order to extend the camera dynamic range. We obtain a sequence of differently exposed interferograms, typically five or six; after that, we compute the corresponding normalized fringe patterns and modulation maps using a typical normalization method. These normalized patterns are combined through a temporal weighted average using as weights the corresponding modulation maps. We show a set of experimental results that prove the effectiveness of the proposed method. © 2011 Elsevier B.V. All rights reserved.Ítem Reduction of speckle noise in digital holography by using digital image processing(ELSEVIER GMBH, URBAN & FISCHER VERLAG, 2005-01-01) Garcia-Sucerquia, J; Ramirez, JAH; Prieto, DV; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaA fundamental problem in optical and digital holography is the presence of speckle noise in the reconstruction process. Many approaches have been carried out in order to overcome such a problem ranging from modifying the spatial coherence of the illumination (optical techniques) to image processing techniques (digital techniques). This work shows the merged use of digital image processing techniques in order to reduce the speckle noise in digital reconstruction of optically recorded Fresnel's holograms. The proposed filtering techniques are illustrated with experimental results. © 2005 Elsevier GmbH. 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