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Ítem Digital opties tool for multi-purpose experimental applications(2010-01-01) Sierra-Sosa, D.-E.; Angel-Toro, L.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThis work presents the results concerning the application of a Discrete Fresnel Transform algorithm (DFT), which was upgraded for modeling and experimenting with scalar diffraction fields, whose characteristics are analyzed. The MATLAB® software environment was used to implement this algorithm, which allows the user to set the initial conditions, corresponding to the optical information at the input plane, by using a graphic friendly user interface (GUI). Then, by using the DFT algorithm, light propagation from the input to the output plane is achieved. The outputs of the algorithm are the maps corresponding to the 2-D distributions amplitude and phase-modulo 2p, or equivalently, the corresponding real and imaginary parts of the complex analytical field. Also, to assist the analysis, line profiles for these maps are provided. Results allow the user synthesizing Fresnel diffraction in presence of multiple components, like lenses, prisms, diffractive gratings, and holographic elements. Indeed, by implementing a series of successive steps, applications like image forming and spatial filtering can be demonstrated. The basis of the algorithm's architecture and some typical results, which closely resemble those from the experiments, are presented.Ítem An integrated system for virtual scene rendering, stereo reconstruction and accuracy estimation(2006-01-01) Marichal-Hernández, J.G.; Pérez Nava, F.; Rosa, F.; Restrepo, R.; Rodríguez-Ramos, J.M.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThis article depicts an integrated system capable of generating virtual stereo scenes, reconstructing a three-dimensional map of distances, and calculating the accuracy of the results obtained. This tool is particularly useful for verifying the validity of distance reconstruction techniques, and is robust enough to use in a wide variety of scenarios since it avoids the need for an image-capture system in laboratory simulations. The importance of the distance reconstruction problem lies in the range of its applications: industrial inspection and quality control, surveillance and security, autonomous vehicles, robotic systems, medical image analysis, image databases, virtual reality, telepresence, and telerobotics. The system is based on the VRML standard for three-dimensional geometric scene representation, on OpenGL for rendering virtual scenes, and on the TRW algorithm for the problem of three-dimensional reconstruction. © 2006 IEEE.Ítem Shack-Hartmann spot dislocation map determination using an optical flow method(OPTICAL SOC AMER, 2014-01-27) Vargas, J.; Restrepo, R.; Belenguer, T.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe present a robust, dense, and accurate Shack-Hartmann spot dislocation map determination method based on a regularized optical flow algorithm that does not require obtaining the spot centroids. The method is capable to measure in presence of strong noise, background illumination and spot modulating signals, which are typical limiting factors of traditional centroid detection algorithms. Moreover, the proposed approach is able to face cases where some of the reference beam spots have not a corresponding one in the distorted Hartmann diagram, and it can expand the dynamic range of the Shack-Hartmann sensor unwrapping the obtained dense dislocation maps. We have tested the algorithm with both simulations and experimental data obtaining satisfactory results. A complete MATLAB package that can reproduce all the results can be downloaded from [http://goo.gl/XbZVOr]. © 2014 Optical Society of America.Ítem Soap film analysis by speckle interferometer(SPIE-INT SOC OPTICAL ENGINEERING, 2003-01-01) Tebaldi, M.; Ángel, L.; Trivi, M.; Bolognini, N.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaIn this paper a soap film is characterized by using a speckle interferometer. The arrangement consists of a double-exposure specklegram obtained through a double-aperture system, by introducing a wedge in front of one aperture in one exposure. It is assumed that a uniform displacement of the diffuser is produced between exposures. The average intensity distribution and the changes experimented by the interferometric fringe visibility in the Fourier plane due to the introduction of a soap film in each exposure are analyzed.