Examinando por Autor "Garcia-Sucerquia, Jorge"

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    Ítem
    Digital lensless holographic microscopy: numerical simulation and reconstruction with ImageJ
    (OPTICAL SOC AMER, 2020-07-01) Trujillo, Carlos; Piedrahita-Quintero, Pablo; Garcia-Sucerquia, Jorge; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
    The description and validation of an ImageJ open-source plugin to numerically simulate and reconstruct digital lensless holographic microscopy (DLHM) holograms are presented. Two modules compose the presented plugin: the simulation module implements a discrete version of the Rayleigh-Somerfield diffraction formula, which allows the user to directly build a simulated hologram from a known phase and/or amplitude object by just introducing the geometry parameters of the simulated setup; the plugin's reconstruction module implements a discrete version of the Kirchhoff-Helmholtz diffraction integral, thus allowing the user to reconstruct DLHM holograms by introducing the parameters of the acquisition setup and the desired reconstruction distance. The plugin offers the two said modules within the robust environment provided by a complete set of built-in tools for image processing available in ImageJ. While the simulation module has been validated through the evaluation of the forecasted lateral resolution of a DLHM setup in terms of the numerical aperture, the reconstruction module is tested by means of reconstructing experimental DLHM holograms of biological samples. (C) 2020 Optical Society of America
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    Ítem
    Three-dimensional surface contouring of macroscopic objects by means of phase-difference images
    (OPTICAL SOC AMER, 2006-09-01) Prieto, Daniel Velasquez; Garcia-Sucerquia, Jorge; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
    We report a technique to determine the 3D contour of objects with dimensions of at least 4 orders of magnitude larger than the illumination optical wavelength. Our proposal is based on the numerical reconstruction of the optical wave field of digitally recorded holograms. The required modulo 2ir phase map in any contouring process is obtained by means of the direct subtraction of two phase-contrast images under different illumination angles to create a phase-difference image of a still object. Obtaining the phase-difference images is only possible by using the capability of numerical reconstruction of the complex optical field provided by digital holography. This unique characteristic leads us to a robust, reliable, and fast procedure that requires only two images. A theoretical analysis of the contouring system is shown, with verification by means of numerical and experimental results. © 2006 Optical Society of America.