Quiroga Mellado, Juan Antonio

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First Name
Juan Antonio
Last Name
Quiroga Mellado
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
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Now showing 1 - 5 of 5
  • Publication
    A isotropic n-dimensional quadrature transform and its applications in fringe pattern processing
    (SPIE--The International Society for Optical Engineering, 2003) Quiroga Mellado, Juan Antonio; Servín Guirado, Manuel; Marroquín Zaleta, José Luis; Gómez Pedrero, José Antonio
    In fringe pattern processing, quadrature operators are useful to obtain the corresponding modulating phase. In the case that a carrier exists (spatial or temporal), there are good methods for phase demodulation as Fourier analysis and asynchronous methods, for example. However, if there is no carrier or is to low, robust demodulation from a single image is a difficult task. In this work we present some recent advances in the processing of single fringe patterns with closed fringes based in a isotropic n-dimensional quadrature transform. In particular we address several problems related with the application of this quadrature operator. One of these problems is the Fringe direction, its role in the demodulation process is discussed and a practical method for its computation is presented. Fringe pattern normalization is also an important subject in the demodulation process from a singe image, taking this into account we present a technique for isotropic fringe pattern normalization based in the n-dimensional quadrature transform. All these techniques together configure a robust method for automatic demodulation of single fringe patterns. The performance and limitations of the method are discussed and illustrated by experimental results.
  • Publication
    Isochromatics demodulation from a single image using the regularized phase tracking technique
    (Taylor and Francis Ltd., 2001-03) Quiroga Mellado, Juan Antonio; Servín Guirado, Manuel
    In this work we propose a robust fringe demodulation technique applied to the analysis of a single isochromatics fringe pattern produced in photoelasticity. The method used is a regularized phase tracking algorithm with a new sequential scanning technique specifically adapted for the characteristics of the isochromatic fringe patterns: possible apparition of closed fringes, large dynamic range in its spatial frequency content and low noise. The performance of the method is discussed and experimental results are presented.
  • Publication
    Temporal evaluation of fringe patterns with spatial carrier with an improved asynchronous phase demodulation algorithm
    (Taylor and Francis Ltd., 2004-01-10) Quiroga Mellado, Juan Antonio; Gómez Pedrero, José Antonio; Servín Guirado, Manuel
    A method for temporal evaluation of fringe patterns with a spatial carrier is presented. The proposed technique consists in the recording of the temporal irradiance fluctuations obtained when a linear variation of the set-up sensitivity is introduced. In this way, the use of a spatial carrier introduces a linear temporal carrier frequency. This allows the use of fast and low time consuming temporal asynchronous demodulation algorithms, similar to those employed in spatial phase shifting techniques. An existing five-step algorithm has been corrected for asynchronous demodulation. It is shown that it is possible to fix the sensitivity variation in such a way that the algorithm presents optimum behaviour against noise and nonlinearities presented by the temporal irradiance signal. Finally, the technique has been applied to measure the shape of an object, using a fringe projection set-up. ©2004 Taylor & Francis LTD.
  • Publication
    Single fringe pattern with closed fringes demodulation using row by row scanners
    (SPIE--The International Society for Optical Engineering, 2006) Quiroga Mellado, Juan Antonio; Estrada, Julio César; Servín Guirado, Manuel; Marroquín Zaleta, José Luis
    Sequential methods like the regularized phase tracker (RPT) are commonly used for fringe pattern demodulation with closed fringes. The only drawback of the RPT method is the necessity to implement a two-dimensional (2D) fringe following scanning in order to obtain the expected modulated phase. In this article we present a new method to demodulate single fringe patterns with closed fringes which use a simple 2D row by row scanning strategy. This is an important contribution because the 2D row by row scanning is extremely fast and easy to implement unlike the fringe following scanning. We have called this method the phase curvature tracker (PCT) because it uses the frequency curvature as regularizer to obtain the expected phase as a C^2 function with continuous curvature.
  • Publication
    Linear systems theory for the analysis of phase-shifting algorithms
    (SPIE--The International Society for Optical Engineering, 2010) Quiroga Mellado, Juan Antonio; Estrada, Julio César; Servín Guirado, Manuel
    Phase-shifting algorithms are methods used for recovering the modulating phase of an interferogram sequence obtained by Phase Stepping Interferometry (PSI) techniques. Typically, the number of interferograms in a PSI sequence is from 3 to around 9 interferograms, although we can find algorithms that works with more than 9 interferograms. In this paper, we are going to show the analysis and design of phase-shifting algorithms from the point of view of the linear systems paradigm from digital signal processing. We will show how this paradigm describes in a general fashion the phase-shifting algorithm systems, and how we can easily design tunable phase-shifting algorithms using this simple scheme.