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
109 results
Search Results
Now showing 1 - 10 of 109
Item Isochromatics demodulation from a single image using the regularized phase tracking technique(Journal of Modern Optics, 2001) Quiroga Mellado, Juan Antonio; Servín Guirado, ManuelIn 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.Item Automatic techniques for evaluation of moire deflectograms(Interferometry '99: Techniques and Technologies, 1999) Quiroga Mellado, Juan Antonio; Villa Hernández, José de Jesús; Crespo Vázquez, DanielIn this work we present two methods for the analysis of moire deflectograms. The first method is a Fourier-transform technique. The second method uses a regularization based method. Both methods are applied to realistic deflectograms and their performances are discussed.Item Real discontinuity preservation algorithm for ESPI fracture measuring(Third International Conference on Experimental Mechanics, 2002) Quiroga Mellado, Juan Antonio; Rodríguez Vera, Ramón; Rayas Álvarez, Juan Antonio; Marroquín Zaleta, José Luis; Rivera, MarianoA well-founded and computationally fast method is presented for filtering and interpolating noisy and discontinuous wrapped phase fields that preserves both the 2π discontinuities that come from the wrapping effect and the true discontinuities that may be present. It also permits the incorporation of an associated quality map, if it is available, in a natural way. Examples of its application to the computation recovery of discontinuous phase fields from speckle interferometry fracture measuring are presented.Item Flexible calibration procedure for fringe projection profilometry(Optical Engineering, 2007) Quiroga Mellado, Juan Antonio; Vargas Balbuena, Javier; Terrón López, M. JoséA novel calibration method for whole field three-dimensional shape measurement by means of fringe projection is presented. Standard calibration techniques, polynomial- and model-based, have practical limitations such as the difficulty of measuring large fields of view, the need to use precise z stages, and bad calibration results due to inaccurate calibration points. The proposed calibration procedure is a mixture of the two main standard techniques, sharing their benefits and avoiding their main problems. In the proposed method, an absolute phase is projected over marked planes placed at unknown positions. The corresponding absolute phase and marks positions are recovered for each plane location. Using Zhang's calibration method, internal camera parameters (also called intrinsic parameters) and the spatial position for each plane are computed. Later on, a polynomial fit of depth with respect to the phase is performed. To obtain the absolute position of an object point, the depth coordinate is obtained by means of the polynomial calibration and its absolute phase. Then the lateral coordinates are computed from the depth, the internal parameters, and the pixel coordinates of the imaged point. Experimental results comparing the proposed method with the standard polynomial- based calibration are shown, demonstrating the feasibility of the proposed technique.Item Wavefront measurement by solving the irradiance transport equation for multifocal systems(Optical Engineering, 2001) Quiroga Mellado, Juan Antonio; Gómez Pedrero, José Antonio; Martínez Antón, Juan CarlosA method for sensing wavefronts is presented. The method is based on the resolution of the irradiance transport equation, which relates the irradiance distribution and the shape of the wavefront of a light beam propagating along a given direction. The method presents no restrictions in the locations of the measurement planes and incorporates an improved procedure to geometrically correct the acquired images to take into account the effect of ray deflection in the propagation of the irradiance distributions. With the proposed technique, we measure the wavefront at the exit pupil of a progressive addition lens and find good agreement with an alternative deflectometric method.Item Regularized quadrature and phase tracking from a single closed-fringe interferogram(Journal of The Optical Society Of America A-Optics Image Science and Vision, 2004) Quiroga Mellado, Juan Antonio; Marroquín Zaleta, José Luis; Servín Guirado, ManuelA new sequential phase demodulator based on a regularized quadrature and phase tracker system (RAPT) is applied to demodulate two-dimensional fringe patterns. This RQPT system tracks the fringe pattern's quadrature and phase in a sequential way by following the path of the fringes. To make the RAPT system more robust to noise, the modulating phase around a small neighborhood is modeled as a plane and the quadrature of the signal is estimated simultaneously with the fringe's modulating phase. By sequentially calculating the quadrature of the fringe pattern, one obtains a more robust sequential demodulator than was previously possible. This system may be applied to the demodulation of a single interferogram having closed fringes.Item Modulo 2π fringe orientation angle estimation by phase unwrapping with a regularized phase tracking algorithm(Journal of the Optical Society of America A-Optics Image Science And Vision, 2002) Quiroga Mellado, Juan Antonio; Servín Guirado, Manuel; Cuevas de la Rosa, Francisco JavierThe fringe orientation angle provides useful information for many fringe-pattern-processing techniques. From a single normalized fringe pattern (background suppressed and modulation normalized), the fringe orientation angle can be obtained by computing the irradiance gradient and performing a further aretangent computation. Because of the 180° ambiguity of the fringe direction, the orientation angle computed from the gradient of a single fringe pattern can be determined only modulo pi. Recently, several studies have shown that a reliable determination of the fringe orientation angle modulo 2π is a key point for a robust demodulation of the phase from a single fringe pattern. We present an algorithm for the computation of the modulo 2π fringe orientation angle by unwrapping the orientation angle obtained from the gradient computation with a regularized phase tracking method. Simulated as well as experimental results are presented.Item Two-step interferometry by a regularized optical flow algorithm(Optics Letters, 2011) Quiroga Mellado, Juan Antonio; Vargas Balbuena, Javier; Sánchez Sorzano, Carlos Óscar; Estrada, Julio César; Carazo García, José MaríaA two-step phase-shifting method, that can demodulate open-and closed-fringed patterns without local sign ambiguity is presented. The proposed method only requires a constant phase-shift between the two interferograms. This phase-shift does not need to be known and can take any value inside the range (0, 2 π), excluding the singular case where it corresponds to π. The proposed method is based on determining first the fringe direction map by a regularized optical flow algorithm. After that, we apply the spiral phase transform (SPT) to one of the fringe patterns and we determine its quadrature signal using the previously determined direction. The proposed technique has been applied to simulated and experimental interferograms obtaining satisfactory results. A complete MATLAB software package is provided in [http://goo.gl/Snnz7].Item Histogram-based method for contrast measurement(Applied Optics, 2000) Quiroga Mellado, Juan Antonio; Sánchez Brea, Luis Miguel; García Botella, Ángel; Bernabeu Martínez, EusebioA histogram-based technique for robust contrast measurement is proposed. The method is based on fitting the histogram of the measured image to the histogram of a model function, and it can be used for contrast determination in fringe patterns. Simulated and experimental results are presented.Item Noise in phase shifting interferometry(Optics Express, 2009) Quiroga Mellado, Juan Antonio; Estrada, Julio César; Servín Guirado, Manuel; Mosiño, Juan Francisco; Cywiak Garbarcewics, MoisésWe present a theoretical analysis to estimate the amount of phase noise due to noisy interferograms in Phase Shifting Interferometry (PSI). We also analyze the fact that linear filtering transforms corrupting multiplicative noise in Electronic Speckle Pattern Interferometry (ESPI) into fringes corrupted by additive gaussian noise. This fact allow us to obtain a formula to estimate the standard deviation of the noisy demodulated phase as a function of the spectral response of the preprocessing spatial filtering combined with the PSI algorithm used. This phase noise power formula is the main result of this contribution.