Examinando por Autor "Quiroga, J.A."

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    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 Aplicada
    We 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.
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    Inspection of an extended surface by an active 3D multiresolution technique
    (Springer-Verlag Berlin Heidelberg, 2009-01-01) Vargas, J.; Restrepo, R.; Quiroga, J.A.; Belenguer, T.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
    Reliable inspection of large surfaces with low depth recovery error is needed in a wide variety of industrial applications, for example in deformation measurement or defect inspection of extended surfaces as communication antennas. Active triangulation measurement systems present a compromise between the depth recovery error and the measured area. For an optimized active three-dimensional measuring system the expected ratio between the depth resolution and the inspected area is in the rage of 10-4. Therefore, if we want to scan a large object with a high level of detail we need multiresolution techniques. In this work we demonstrate the application of an active triangulation multiresolution method for the inspection of communication antennas. The technique is based on a standard camera-projector system. The result is a global measurement formed by a set of superposed local measurement with high depth resolution. © 2009 Springer-Verlag Berlin Heidelberg.