Optica Aplicada

URI permanente para esta comunidad

https://hdl.handle.net/10784/1122

Genera y transfiere conocimiento y apropia métodos y tecnologías en las áreas de procesamiento óptico de información y metrología óptica, relevantes para el avance científico, académico y productivo.

Líneas de investigación: Holografía; Metrología Óptica.
Código Minciencias: COL0011527.
Categoría 2019: A.
Escuela: Ciencias.
Departamento académico: Ciencias Físicas.
Coordinador: Elena Montilla; Carlos Andrés Trujillo.
Correo electrónico: emontill@eafit.edu.co; catrujilla@eafit.edu.co

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Mostrando 1 - 20 de 141

Features on photorefractive registered speckles
(SPIE, 1999-04-29) Ángel-Toro, Luciano; Bolognini, Néstor; Tebaldi, Myrian; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 the crystal by an optical system whose pupil consists of two identical holes. The intensity distribution of the speckle pattern imaged onto the BSO crystal leads to a space-charge field by drift of photocarriers, resulting in a refractive index modulation. The main features of diffracted read-out light at the Fourier plane are discussed. © (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Photorefractive optical processing: some proposals
(SPIE, 1999-04-29) Ángel-Toro, Luciano; Bolgnini, Néstor; Tebaldi, Myrian; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 read-out with coherent light. The system for the Lau arrangement behaves as a combination of an amplitude and a birefringence phase grating. In both cases, it is possible to control the visibility and to produce a contrast reversion of fringes by using an analyzer. Besides, Lau and Talbot interferometers based on the mentioned approach and their alternative experimental arrangements will be discussed. © (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Phase stepping in Lau interferometry
(Elsevier, 1999-06-15) Ángel-Toro, Luciano; Tebaldi, Myrian; Henao, Rodrigo; Ángel-Toro, Luciano; Tebaldi, Myrian; Henao, Rodrigo; Universidad EAFIT. Departamento de Ciencias Básicas; langel@eafit.edu.co; Óptica Aplicada
The implementation of phase shifting interferometry to analyze the Lau interferometric fringe patterns is proposed. The fundamentals of this application are theoretically discussed and the basis of the phase map interpretation is outlined. The three steps algorithm is used to depict the phase maps of lens-like test objects and an application for measuring focal lengths of lenses is reported. Experimental results are presented. q1999 Elsevier Science B.V. All rights reserved.
Contrast inversion in the Lau phenomena implemented with a photorefractive grating
(SPIE, 1999-07-06) Ángel Toro, Luciano; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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, by properly setting the pass plane orientation of an analyzer located at the crystal output.
Talbot and Lau phenomena implementation via a photorefractive converter
(SPIE, 1999-07-06) Tebaldi, Myrian Cristina; Ángel Toro, Luciano; Bolognini, Néstor Alberto; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 to reverse the contrast of the self images and Lau fringes by rotating an analyzer. A theoretical approach is outlined and the predicted behavior is confirmed by results obtained under different experimental conditions. We have taken advantage of the arrangements to demonstrate some applications.
Double aperture speckle method using a BSO crystal for in plane displacement
(SPIE, 1999-07-06) Trivi, Marcelo Ricardo; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto; Ángel Toro, Luciano; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto; Trivi, Marcelo Ricardo; Ángel Toro, Luciano; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 shown.
Speckle photography through different multiaperture pupils
(SPIE/ 18th Congress of the International Commission for Optics, 1999-07-19) Ángel Toro, Luciano; Tebaldi, Myrian Cristina; Bolognini, Néstor Alberto; Trivi, Marcelo Ricardo; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 plane, for uniform in-plane displacement double- exposed specklegrams through different pupils recording, are analyzed in terms of the geometric parameters of the pupils. Experimental evidences are presented.
Interpretación Cuantitativa de Interferogramas Holográficos por Medición de la Fase
(Sociedad Colombiana de Física, 2000-01-01) Velásquez, Daniel Ignacio; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
Speckle photography with different pupils in a multiple-exposure scheme
(OPTICAL SOC AMER, 2000-01-01) Angel, L; Tebaldi, M; Bolognini, N; Trivi, M; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
The use of different multiple-aperture pupils for recording each image in speckle photography is proposed. The introduction of suitable spatial frequency carriers, by internally modulating imaged speckles, allows one to selectively isolate or combine the spectral content of different images into spatially separated regions in the Fourier plane. Theoretical and experimental results extend the speckle photography technique to the depiction of several specklegrams of multiple uniform in-plane displacements. In this case, because different pupils are considered for recording, the cross-correlation functions for the amplitudes and intensities in the image plane are calculated on the basis of the statistical properties of the object. Also, the ensemble-average intensity in the Fourier plane is analytically derived, and fringe visibility is investigated. © 2000 Optical Society of America.
Optical processing by fringed speckles registered in a BSO crystal
(SPIE, 2000-01-01) Tebaldi, M.; Toro, L.A.; Trivi, M.; Bolognini, N.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
An alternative image multiplexing technique, employing a multiple-aperture pupil for each exposure, is presented. The aperture arrangement of the pupil is modified between exposures. A thick photo-refractive BSO crystal is used as recording material. The technique allows concentrating the spectral components of a pair of images selectively into isolated spots in the Fourier plane. Two applications are proposed, in image processing and optical metrology.
Speckle photography with different pupils in a multiple-exposure scheme
(Optical Society of America, 2000-01-01) Ángel Toro, Luciano; Bolognini, Néstor Alberto; Tebaldi, Myrian Cristina; Trivi, Marcelo Ricardo; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
The use of different multiple-aperture pupils for recording each image in speckle photography is proposed -- The introduction of suitable spatial frequency carriers, by internally modulating imaged speckles, allows one to selectively isolate or combine the spectral content of different images into spatially separated regions in the Fourier plane -- Theoretical and experimental results extend the speckle photography technique to the depiction of several specklegrams of multiple uniform in-plane displacements -- In this case, because different pupils are considered for recording, the cross-correlation functions for the amplitudes and intensities in the image plane are calculated on the basis of the statistical properties of the object -- Also, the ensemble-average intensity in the Fourier plane is analytically derived, and fringe visibility is investigated. © 2000 Optical Society of America [S0740-3232(00)01701-4]OCIS codes: 120.0120, 120.3180, 120.3940, 120.6160
Optical processing by fringed speckles registered in a BSO crystal
(SPIE, 2000-07-28) Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Ángel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Ángel-Toro, Luciano; Universidad EAFIT. Departamento de Ciencias Básicas; langel@eafit.edu.co; Óptica Aplicada
An alternative image multiplexing technique, employing a multiple-aperture pupil for each exposure, is presented. The aperture arrangement of the pupil is modified between exposures. A thick photorefractive BSO crystal is used as recording material. The technique allows concentrating the spectral components of a pair of images selectively into isolated spots in the Fourier plane. Two applications are proposed, in image processing and optical metrology. © 2000 Society of Photo-Optical Instrumentation Engineers. © 2000 Society of Photo-Optical Instrumentation Engineers
New multiple aperture arrangements for speckle photography
(Elsevier B.V, 2000-08-01) Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Angel-Toro, Luciano (langel@eafit.edu.co); Óptica Aplicada
Abstract. We propose a multiple exposure specklegram by using an optical system whose multiple aperture pupil changes between exposures. In particular, we analyze experimentally two arrangements and we show that it is possible to store the required information by employing a minimum number of registers if an adequate selection of the pupil is done. We study the effect of the decorrelation (among the stored speckle pattern) introduced by changing the multiple aperture pupil arrangements between exposures. The fundamentals and the relative benefits of the new scheme proposed are discussed on the basis of a fringe visibility analysis.
New multiple aperture arrangements for speckle photography
(ELSEVIER SCIENCE BV, 2000-08-01) Tebaldi, M; Toro, LA; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
We propose a multiple exposure specklegram by using an optical system whose multiple aperture pupil changes between exposures. In particular, we analyze experimentally two arrangements and we show that it is possible to store the required information by employing a minimum number of registers if an adequate selection of the pupil is done. We study the effect of the decorrelation (among the stored speckle pattern) introduced by changing the multiple aperture pupil arrangements between exposures. The fundamentals and the relative benefits of the new scheme proposed are discussed on the basis of a fringe visibility analysis. © 2000 Published by Elsevier Science B.V.
Double exposure specklegrams obtained by using scaled aperture pupils
(SPIE-INT SOC OPTICAL ENGINEERING, 2001-01-01) Angel, L; Tebaldi, M; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 analysed on the basis of double-exposed image speckle, before and after a diffuser inplane displacement is done. The apertures have the same shape but its scale is modified between exposures. Note that the relative position of the aperture is maintained. In particular, we analyse a simple case that uses a circular aperture whose diameter is modified for recording each image. The intensities in the image plane and the fringe visibility are evaluated, in terms of the geometric characteristics of the pupils. © 2001 SPIE · 0277-786X/01/$15.00.
Properties of speckle patterns generated through multiaperture pupils
(ELSEVIER SCIENCE BV, 2001-05-15) Angel, L; Tebaldi, M; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
The characteristics of the image speckles obtained through multiple aperture pupils are theoretically analyzed in terms of the parameters defining the pupils. The possibility of interpreting and synthesizing the image speckle distribution in terms of rather elementary structures is considered, based on the Fourier optics analysis. Then, first and second order statistical properties of the speckle patterns are studied by evaluating both the mutual intensity and the auto-correlation intensity of speckle distributions obtained by means of pupils consisting of identical apertures. Experimental results are presented to confirm the analysis. © 2001 Published by Elsevier Science B.V.
Propierties of speckle patterns generated through multiaperture pupils
(Elsevier, 2001-05-15) Ángel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Ángel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Ángel-Toro, Luciano (langel@eafit.edu.co); Óptica Aplicada
The characteristics of the image speckles obtained through multiple aperture pupils are theoretically analyzed in terms of the parameters defining the pupils. The possibility of interpreting and synthesizing the image speckle distribution in terms of rather elementary structures is considered, based on the Fourier optics analysis. Then, first and second order statistical properties of the speckle patterns are studied by evaluating both the mutual intensity and the auto-correlation intensity of speckle distributions obtained by means of pupils consisting of identical apertures. Experimental results are presented to confirm the analysis.
Recuperación de la energía radiada por conductores de corriente alterna
(Sociedad Colombiana de Física, 2001-06-01) Marulanda, José Ignacio; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
Logic operations by using modulated speckle
(SPIE, 2001-08-14) Tebaldi, Myrian; Ángel-Toro, Luciano; Trivi, Marcelo; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 system of fringes. The input images are sequentially encoded by using a different pupil during each exposure. The pupil arrangements implemented are selected to concentrate in each spot the spectral information corresponding to not more than two exposures. The spectral amplitude components for a pari of exposures are added into the common diffraction spots. All the diffraction spots contain information about a pair of inputs. Then, an image binary operation can be carried out in each spot. The technique is implemented by using as recording media photographic films and photorefractive crystals. The BSO crystal as recording medium is quite adequate in the applications proposed because it permits multiple storage in real time. However, due to its volume nature, each speckle grain exhibits angular selectivity in addition to those features observed in bidimensional media. © (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Double exposure specklegrams obtained by using scaled aperture pupils
(SPIE, 2001-08-14) Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
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 and after a diffuse in-plane displacement is done. The apertures have the same shape but its scale is modified between exposures. Note that the relative position of the aperture is maintained. In particular, we analyze a simple case that uses a circular aperture whose diameter is modified for recording each image. The intensity in the image plane and the fringe visibility are evaluated, in terms of the geometric characteristics of the pupils. © (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

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