Person:
González Cano, Agustín

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First Name
Agustín
Last Name
González Cano
URI
https://hdl.handle.net/20.500.14352/79943
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
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1995 - 19999
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End date: 1999 × Start date: 1995 ×

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Now showing 1 - 9 of 9
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    Measurement of the degree of salinity of water with a fiber-optic sensor
    (Applied Optics, 1999) Esteban Martínez, Óscar; Navarrete Fernández, María Cruz; González Cano, Agustín; Bernabeu Martínez, Eusebio
    A fiber-optic sensor based on surface-plasmon resonance for the determination of the refractive index is used for measuring the degree of salinity of water. The transducing element consists of a multilayer structure deposited on a side-polished monomode optical fiber. Measuring the attenuation of the power transmitted by the fiber shows that a linear relation with the refractive index of the outer medium of the structure is obtained. The system is characterized by use of a varying refractive index obtained with a mixture of water and ethylene glycol. Experimental results show that the sensor can be used as a salinity-degree measurement device with environmental applications.
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    A fast method to measure the irradiance response of image processing systems
    (Measurement Science and Technology, 1995) Quiroga Mellado, Juan Antonio; González Cano, Agustín; Bernabeu Martínez, Eusebio
    A method to estimate in a fast and simple way the response of an image acquiring system (such as a charge-coupled device camera plus an image-processing board) for a monochromatic light source is presented. Two images, whose irradiances are related in a known way, are acquired, and the corresponding grey levels of the responses of the system are correlated pixel to pixel. From this correlation and the relationship between the irradiances of the images, a relative estimation of the irradiance response of the system can be obtained by means of simple algorithms. This method is fast and easy to implement and the results obtained are satisfactory.
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    Method of error analysis for phase-measuring algorithms applied to photoelasticity
    (Applied Optics, 1998) Quiroga Mellado, Juan Antonio; González Cano, Agustín
    We present a method of error analysis that can be applied for phase-measuring algorithms applied to photoelasticity. We calculate the contributions to the measurement error of the different elements of a circular polariscope as perturbations of the Jones matrices associated with each element. The Jones matrix of the real polariscope can then be calculated as a sum of the nominal matrix and a series of contributions that depend on the errors associated with each element separately. We apply this method to the analysis of phase-measuring algorithms for the determination of isoclinics and isochromatics, including comparisons with real measurements.
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    Stable-marriages algorithm for preprocessing phase maps with discontinuity sources
    (Applied Optics, 1995) Quiroga Mellado, Juan Antonio; González Cano, Agustín; Bernabeu Martínez, Eusebio
    A new algorithm is proposed for solving the problems associated with discontinuity sources in phase maps. It is based on the stable-marriages algorithm and is implemented as a recursive procedure. With this technique, discontinuity sources of opposite sign are connected by a set of cut lines that fulfills a stability criterion and possesses the minimum cut length of the stable sets. The algorithm is fast and easy to implement and has proved efficient, as experimental results show.
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    Application of regularization methods to the analysis of photoelastic fringe patterns
    (Interferometry 99: Techniques and Technologies, 1999) Quiroga Mellado, Juan Antonio; González Cano, Agustín
    In this work we present the application of a regularization algorithm to the processing of photoelastic hinge patterns. The method used is a modified phase tracking algorithm applied to phase-shifted images. In particular, we present an algorithm for isoclinics-isochromatics separation that uses only five images. The performance of the method is discussed and experimental results are presented.
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    On the dependence on isoclinics of the modulation of isochromatic phase maps
    (Optik, 1999) Quiroga Mellado, Juan Antonio; González Cano, Agustín
    In this work we evaluate the dependence on isoclinics of the modulation of the isochromatic phase maps when phase-shifting algorithms are applied to experiments of photoelasticity. This dependence makes conventional phase-shifting algorithms unsuitable for that application.
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    Phase measuring algorithm for extraction of isochromatics of photoelastic fringe patterns
    (Applied Optics, 1997) Quiroga Mellado, Juan Antonio; González Cano, Agustín
    In recent years phase-measuring techniques have been applied to the problem of extracting information of photoelastic data. We present a new phase-measuring algorithm for extraction of the isochromatics of photoelastic fringe patterns. The algorithm permits the extraction of the isochromatic phase with almost no influence from the isoclinics, thus avoiding the usual problems of low-modulation areas associated with isoclinics. The isochromatic phase map obtained with this algorithm is well suited for a full separation of the stress components in a sample. The algorithm can be used with any commercial diffuse-light circular polariscope.
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    Phase-unwrapping algorithm based on an adaptive criterion
    (Applied Optics, 1995) Quiroga Mellado, Juan Antonio; González Cano, Agustín; Bernabeu Martínez, Eusebio
    A new algorithm for phase unwrapping of phase maps with noise or logical inconsistencies is proposed. It is based on the use of an adaptive threshold and the second difference of the locally unwrapped phase as a selection criterion for the pixels to be processed.
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    Stress separation from photoelastic data by a multigrid method
    (Measurement Science and Technology, 1998) Quiroga Mellado, Juan Antonio; González Cano, Agustín
    An application of multigrid techniques for the separation of principal stresses in plane stress systems is presented. By establishing the equilibrium equations and determining the value of shear from photoelastic data a system of partial differential equations is obtained, which can be solved by applying a multigrid method. Multigrid methods are comparable to Fourier methods in efficiency and robustness and can be applied to processing areas of arbitrary shape.