• Analysis of vibrations in a plate using interferometric methods 

    Ángel-Toro, Luciano; Prieto, Daniel Velasquez; Rueda Muñóz, Edgar Alberto (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ingeniería, 2004-10-21)
    In this work some frequencies and modes of vibration of a thin plate were determined using interferometric methods like: real-time holographic interferometry, time-average holographic interferometry, digital speckle pattern ...
  • Contrast inversion in the Lau phenomena implemented with a photorefractive grating 

    Ángel Toro, Luciano; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto (SPIE, 1999-07-06)
    It was implemented the Lau effect with a grating registered in a BSO crystal. Two different arrangement were analyzed. In both cases, it is possible to control the visibility and to produce the contrast inversion of fringes, ...
  • DC term filtering techniques in digital holography 

    Velásquez-Prieto, Daniel; García Sucerquia, Jorge Iván; Herrera Ramírez, Jorge Alexis (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ingeniería, 2004-10-21)
    In 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 ...
  • Design of a control system for interferometric fringe stabilization system with remote access 

    Espitia-Gómez, Javier; Ángel Toro, Luciano; Velásquez Prieto, Daniel (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2013-11-18)
    Stability in a fringe pattern is a necessary condition in interferometric processes, such as holography, and not always is enough the use of passive stabilization systems, like holographic tables, in particular, when ...
  • Double aperture speckle method using a BSO crystal for in plane displacement 

    Trivi, Marcelo Ricardo; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto; Ángel Toro, Luciano (SPIE, 1999-07-06)
    The possibility of using a BSO crystal as a recording medium of specklegrams with carrying frequency fringes, to storage multiple interferograms, for uniform in-plane displacements, is presented. Experimental results are ...
  • Double exposure specklegrams obtained by using scaled aperture pupils 

    Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; langel@eafit.edu.co (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2001-08-14)
    In speckle photography the pupil aperture is usually not modified between exposures. In our work, the change of the pupil aperture scale between exposures is analyzed on the basis of double-exposed image speckle, before ...
  • Effect of the internal modulation of speckles in displacement measurements in optical vortex metrology 

    Gómez-Tejada, Daniel; Sierra-Sosa, Daniel; Castañeda, Román; Ángel-Toro, Luciano (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2013-11-08)
    The Optical Vortex Metrology is based on the possibility of characterizing, through topological and morphological parameters, each one of the vortices existing in the phase of the optical field, or in a pseudo-phase obtained ...
  • Evaluation between methods for the color measurement in holograms by using a CMOS-RGB camera and a spectrometer 

    Palacios Ortega, Natalith; Velásquez Prieto, Daniel (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2013-07-22)
    Many models and methods commonly used in colorimetry have been incorporated to the study and knowledge of the colorimetric properties in the reflection color holograms; these methods have reported the possibilities of color ...
  • Features on photorefractive registered speckles 

    Ángel-Toro, Luciano; Bolognini, Néstor; Tebaldi, Myrian (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 1999-04-29)
    The recording and read-out of a volume speckle pattern is investigated for transmission geometry. The modulation of the 3D speckle grains appears when the image of a coherently illuminated random diffusor is formed onto ...
  • Logic operations by using modulated speckle 

    Tebaldi, Myrian; Ángel-Toro, Luciano; Trivi, Marcelo; Bolognini, Néstor (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2001-08-14)
    An alternative image multiplexing technique is proposed. In the arrangement implemented, the input is imaged by introducing a multiple aperture pupil in the imaging lens. Then, the speckle pattern is modulated by several ...
  • Phase-difference images by digital holography applied to 3D surface contouring 

    Velásquez-Prieto, Daniel; García Sucerquia, Jorge Iván (Academia Colombiana de Ciencias Exactas Físicas y Naturales; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2005-06)
    The 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, ...
  • Photorefractive optical processing: some proposals 

    Ángel-Toro, Luciano; Bolgnini, Néstor; Tebaldi, Myrian; langel@eafit.edu.co (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 1999-04-29)
    Some proposals on Lau and Talbot fringes formation based on a grating registered as birefringence modulation in a photorefractive crystal, will be presented. In the Talbot case, the stored grating can be replicated if ...
  • Reduction of speckle noise in digital holography 

    Velásquez-Prieto, Daniel; García Sucerquia, Jorge Iván; Castañeda Sepúlveda, Román; Herrera Ramírez, Jorge Alexis (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ingeniería, 2004-10-21)
    A fundamental problem in holography, as well optical as digital, is the presence of speckle noise in the reconstruction process -- Many approaches have been carried out in order overcome such a problem, ranging from altering ...
  • Soap film analysis by speckle interferometer 

    Tebaldi, Myrian; Ángel-Toro, Luciano; Trivi, Marcelo; Bolognini, Néstor (SPIE; Grupo de Investigación de Óptica Aplicada; Escuela de Ciencias y Humanidades, 2003-11-18)
    In 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 ...
  • Speckle photography through different multiaperture pupils 

    Ángel Toro, Luciano; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto; Trivi, Marcelo Ricardo (SPIE/ 18th Congress of the International Commission for Optics, 1999-07-19)
    An image multiplexing method based on the internal modulation of speckle grains by employing different multiple aperture pupils for recording is proposed. The interferometric fringes profile and visibility in the Fourier ...
  • Talbot and Lau phenomena implementation via a photorefractive converter 

    Tebaldi, Myrian Cristina; Ángel Toro, Luciano; Bolognini, Néstor Alberto (SPIE, 1999-07-06)
    We propose a novel implementation of the Lau and Talbot effects. It employs a grating registered as modulation of birefringence in a Bi12SiO20 crystal. The systems proposed allow to control the visibility and in particular ...