Person:
Quiroga Mellado, Juan Antonio

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First Name
Juan Antonio
Last Name
Quiroga Mellado
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Óptica
Area
Optica
Identifiers
UCM identifierORCIDScopus Author IDDialnet IDGoogle Scholar ID

Search Results

Now showing 1 - 9 of 9
  • Publication
    Measurement of surface topography by RGB Shadow-Moiré with direct phase demodulation
    (Elsevier Sci. Ltd., 2006-12) Quiroga Mellado, Juan Antonio; Gómez Pedrero, José Antonio; Terrón López, M. José; Crespo Vázquez, Daniel
    In this paper we present the application of a direct demodulation method for the measurement of surface topography by means of Shadow-Moiré. In our set-up, we use three LEDs (with green, red and blue peak wavelengths) to illuminate the grating. Due to the different position of these light sources, a polychromatic Shadow-Moiré fringe pattern is produced, which can be described as the superposition of three monochromatic (red, green and blue) fringe patterns. Taking the image of this polychromatic fringe pattern with a RGB CCD camera, we get a monochromatic fringe pattern stored at each RGB channel of the CCD. The direct demodulation algorithm employed uses these fringe patterns to calculate the wrapped phase map. After unwrapping the phase map using a standard multi-grid technique, we implemented an automatic procedure to detect the area of interest of the phase map by removing low modulation zones and to calculate the absolute value of the phase. In this way it is possible to determine the topography of a surface with a single RGB snapshot maintaining a simple experimental set-up, which is an important feature, especially for the study of dynamic phenomena such as deformations. We present the experimental results obtained after measuring different objects with both smooth and rough surface textures.
  • Publication
    Recent advances in automatic demodulation of single fringe patterns
    (Springer Verlag Berlin, 2006) Quiroga Mellado, Juan Antonio; Crespo Vázquez, Daniel; Gómez Pedrero, José Antonio; Martínez Antón, Juan Carlos
  • Publication
    Automatic demodulation of single-image fringe patterns with application in the evaluation of external defects in aeronautical surfaces by shadow-moire
    (VDI-VDE - Verlag GMBH, 2004) Quiroga Mellado, Juan Antonio; Crespo Vázquez, Daniel; Fournier, N.; Martínez Antón, Juan Carlos
    Automatic demodulation of single-image fringe patterns is of great importance in research areas were it is difficult to apply standard phase evaluation techniques such as phase sampling or Fourier transform methods. In this work we will present recent advances in the automatic demodulation of single-image fringe patterns. In particular we have used two methods for the demodulation process: the regularized phase tracker (RPT) and the isotropic quadrature transform (IQT). For a reliable and automatic demodulation of real fringe patterns by means of the RPT and the IQT techniques we have developed strategies for fringe pattern normalization, modulo 2π fringe orientation computation and adaptive processing, which all together configure a reliable and fast demodulation scheme. We have applied these techniques in the evaluation of external defects in aeronautical surfaces by the shadow moire technique and for this purpose a software package has been developed that works together with an in-line inspection system for indentation assessment designed by the company NDT-Expert. Experimental results of the system will be shown and performance will be discussed.
  • Publication
    Adaptive spatiotemporal structured light method for fast three-dimensional measurement
    (Spie-Soc Photo-Optical Instrumentation Engineers, 2006-10) Quiroga Mellado, Juan Antonio; Crespo Vázquez, Daniel; Vargas Balbuena, Javier; Gómez Pedrero, José Antonio
    We present a high-speed 3-D spatiotemporal shape measurement technique by means of structured light. Current methods use a constant number of images that do not take into account the available temporal continuity of the measured object. That is, they focus on acquiring and processing as quickly as possible a fixed number of images to solve for the correspondence problem and later obtain the 3-D shape by triangulation. The number of images used imposes the use of some spatial support. The major contribution of our research is a new spatiotemporal scheme that, depending on the object's movement, adaptively uses the maximum number of projected images consistent with the local temporal continuity, therefore solving the correspondence problem with the minimum possible spatial support for each position. This is achieved by the use of a hybrid color pattern composed of an analog sinusoidal periodic code in the red channel and a digital binary spatial code in the blue channel that is cyclically displaced. No subpixel calculation is used and it is possible to implement error correction strategies that make the method fast and reliable, enabling dynamic online 3-D measurement of objects in movement.
  • Publication
    Fast algorithm for estimation of the orientation term of a general quadrature transform with application to demodulation of an n-dimensional fringe pattern
    (The Optical Society of America, 2004-11-20) Quiroga Mellado, Juan Antonio; Crespo Vázquez, Daniel; Gómez Pedrero, José Antonio
    The spatial orientation of fringes has been demonstrated to be a key point in reliable phase demodulation from a single n-dimensional fringe pattern, regardless of the frequency spectrum of the signal. Recent publications have shown a general method for determination of the orientation factor by use of a regularized phase-tracking (RPT) algorithm. We propose a generalization of a RPT algorithm for estimation of the spatial orientation in a general n-dimensional case. The proposed algorithm makes use of a simplified cost function that remains one dimensional regardless of the dimension of the problem. This makes the calculation faster than with a standard RPT algorithm, with which it is necessary to minimize an n + 1-dimensional cost function for each point of the sample space. We have applied the method to the three-dimensional demodulation of a time-evolving fringe pattern, with good results.
  • Publication
    XtremeFringe: state-of-the-art software for automatic processing of fringe patterns
    (SPIE--The International Society for Optical Engineering, 2007) Quiroga Mellado, Juan Antonio; Crespo Vázquez, Daniel; Gómez Pedrero, José Antonio
    XtremeFringe is a new library for fringe pattern processing which incorporates modem methods for automatic analysis including fringe pattern demodulation, fringe pattern filtering and phase unwrapping methods. XtremeFringe (R) is written in C# and is usable as an assembly from any NET language (C#, C++, .NET, J#) and additionally as a Matlab toolbox, which ensures an easy adaptation in custom applications, providing the user with a versatile and powerful tool for fringe pattern analysis in a flexible way. The functions of XtremeFringe are suitable to be employed in metrological applications such interferometry, photoelasticity, Moire techniques, holography, etc. supplying the user with up-to-date fringe analysis tools. In this work, we demonstrate the capabilities of the XtremeFringe library, processing different examples showing the ability of the library to analyze complex fringe patterns in a fast, reliable and automatic way.
  • Publication
    Estimation of the orientation term of the general quadrature transform from a single n-dimensional fringe pattern
    (Optical Society of America, 2005-03) Quiroga Mellado, Juan Antonio; Servín Guirado, Manuel; Marroquín Zaleta, José Luis; Crespo Vázquez, Daniel
    The spatial orientation of the fringe has been demonstrated to be a key point in the reliable phase demodulation from a single n-dimensional fringe pattern regardless of the frequency spectrum of the signal. The recently introduced general n-dimensional quadrature transform (GQT) makes explicit the importance of the fringe orientation in the demodulation process. The GQT is a quadrature operator that transforms cos φ into -sin φ-where φ is the modulating phase-and it is composed of two terms: an orientation factor directly related to the fringe's spatial orientation and an isotropic n-dimensional generalization of the one-dimensional Hilbert transform. We present a method for the determination of the orientation factor in a general n-dimensional case and its application to the demodulation of a single fringe pattern by the GQT. We have tested the algorithm with simulated as well as real photoelastic fringe patterns with good results.
  • Publication
    Fourier based design of asynchronous phase detection algorithms
    (SPIE--The International Society for Optical Engineering, 2007) Quiroga Mellado, Juan Antonio; Gómez Pedrero, José Antonio; Crespo Vázquez, Daniel
    Phase detection is an important issue when dealing with optical metrology techniques for which the magnitude to be measured is encoded through the phase of a given fringe pattern. Asynchronous phase detection techniques are employed when the rate of phase change (frequency) it is not known. These techniques always present a variable frequency response, in other words, their ability to recover properly the phase depends strongly on the local frequency. In many experiments, it is possible to have a rough knowledge about the range of frequencies involved. Therefore, it constitutes a great advantage to have a procedure to design an asynchronous demodulation method which is suited to a particular frequency response for a given experiment. In this way, we get a better behaviour against noise which leads to more accurate and reliable phase extraction. In this work we present a technique to design asynchronous demodulation algorithms with a desired frequency response using a Fourier-based technique. The method allows the design of algorithms with a limited algebraic error in the recovered phase which have better properties than standard asynchronous phase detection techniques as it is shown in numeric and real experiments.
  • Publication
    New method for three-dimensional shape registration of prismatic objects
    (Spie-Society of Photo-Optical Instrumentation Engineers, 2006-02) Quiroga Mellado, Juan Antonio; Vázquez Moliní, Daniel; Crespo Vázquez, Daniel
    A new method for 3-D shape registration of prismatic objects is presented. The term prismatic object denotes any object with sharp boundaries on its surface. These kinds of objects cannot be correctly registered with typical existing methods, which require smooth overlapping of the whole surface. The method presented here is based on the use of reference marks, placed on a planar glass plate that is attached to the prismatic object. Two 3-D range measurements of the object are then acquired, before and after rotating the object by approximately 180 deg. Using the reference marks on the glass and two different calibrations of the 3-D range scanning system, these two range measurements can be correctly merged to provide a full 3-D range scan of the prismatic object.