Papers by Ismael De la Rosa
Tidskrift för Sveriges sjuksköterskor, Jan 15, 1976
Revista Iberoamericana de Computación y Sistemas CIC-IPN, Vol 14, No. 2, septiembre 2010, pp. 145-150, Dec 31, 2010
Un importante paso en el análisis de patrones de franjas es el llamado desenvolvimiento de fase. ... more Un importante paso en el análisis de patrones de franjas es el llamado desenvolvimiento de fase. Aunque esta tarea puede ser realizada fácilmente usando algoritmos dependientes del camino, muchas veces, sin embargo, estos algoritmos no son suficientemente robustos especialmente con la presencia de ruido. Por otro lado, los métodos independientes del camino tales
This paper presents an improvement in the method for storing information using detour type multic... more This paper presents an improvement in the method for storing information using detour type multichannel holograms. This makes in possible to increase the number of image-processing operations at the retrieval stage. One of the main contributions of this work is in showing that this type of hologram is sensitive to color processing. As far as we know, this is the first effort made toward implementing color in binary holograms as shown in the experimental results.
Advanced Image Acquisition, Processing Techniques and Applications I, 2012
Journal of the European Optical Society: Rapid Publications, 2013
Continuous, mathematically smooth Phase Objects with radial symmetry are reconstructed from cross... more Continuous, mathematically smooth Phase Objects with radial symmetry are reconstructed from cross sections of their refractive index distribution by a novel method, consisting of a linear combination of Gaussian basis functions, whose technical details are discussed. As an application example, this approach is used to get a fast and accurate estimation of the temperature distribution of an actual soldering tip.
Optics and Lasers in Engineering, 2010
In our recently reported work [1] (Villa et al., 2009) we derived a regularized quadratic-cost fu... more In our recently reported work [1] (Villa et al., 2009) we derived a regularized quadratic-cost function, which includes fringe orientation information, for denosing fringe pattern images. In this work we adopt such idea for denoising wrapped phase-maps. We use a regularized cost-function that uses complex-valued Markov random fields (CMRFs) with orientation information of the filtering direction along isophase lines. The advantage of using an anisotropic filter along isophase lines is that phase and noise can be properly separated while 2p phase jumps are preserved even in high frequency zones. Apart from its robustness, the outstanding advantage of our method is its minimal computational effort. We present some results processing simulated and real phase-maps.
Journal of the European Optical Society: Rapid Publications, 2014
In this paper we present a novel algorithm for phase unwrapping where only a subset of data from ... more In this paper we present a novel algorithm for phase unwrapping where only a subset of data from the wrapped phase map is used to reconstruct the unwrapped phase map as a linear combination of radial basis functions (RBF's). For noisy phase maps this algorithm gives better results than three reference algorithms based on radial basis functions, Zernike polynomials and path dependent phase unwrapping strategies.
Journal of the European Optical Society: Rapid Publications, 2013
The present work introduces an alternative method to deal with digital image restoration into a B... more The present work introduces an alternative method to deal with digital image restoration into a Bayesian framework, particularly, the use of a new half-quadratic function is proposed which performance is satisfactory compared with respect to some other functions in existing literature. The bayesian methodology is based on the prior knowledge of some information that allows an efficient modelling of the image acquisition process. The edge preservation of objects into the image while smoothing noise is necessary in an adequate model. Thus, we use a convexity criteria given by a semi-Huber function to obtain adequate weighting of the cost functions (half-quadratic) to be minimized. The principal objective when using Bayesian methods based on the Markov Random Fields (MRF) in the context of image processing is to eliminate those effects caused by the excessive smoothness on the reconstruction process of image which are rich in contours or edges. A comparison between the new introduced scheme and other three existing schemes, for the cases of noise filtering and image deblurring, is presented. This collection of implemented methods is inspired of course on the use of MRFs such as the semi-Huber, the generalized Gaussian, the Welch, and Tukey potential functions with granularity control. The obtained results showed a satisfactory performance and the effectiveness of the proposed estimator with respect to other three estimators.
Journal of the Optical Society of America A, 2014
The physical theory of the Foucault test has been investigated to represent the complex amplitude... more The physical theory of the Foucault test has been investigated to represent the complex amplitude and irradiance of the shadowgram in terms of the wavefront error; however, most of the studies have limited the treatment for the particular case of nearly diffraction-limited optical devices (i.e., aberrations smaller than the wavelength). In this paper we discard this restriction, and in order to show a more precise interpretation from the physical theory we derive expressions for the complex amplitude and the irradiance over an optical device with larger aberrations. To the best of our knowledge, it is the first time an expression is obtained in closed form. As will be seen, the result of this derivation is obtained using some properties of the Hilbert transform that permit representing the irradiance in a simple form in terms of the partial derivatives of the wavefront error. Additionally, we briefly describe from this point of view a methodology for the quantitative analysis of the test. © 2014 Optical Society of America OCIS codes: (120.4800) Optical standards and testing; (120.3180) Interferometry.
Optik - International Journal for Light and Electron Optics, 2013
The computational efficiency of 14 optical detectors over six types of transformations, namely: b... more The computational efficiency of 14 optical detectors over six types of transformations, namely: blur, illumination, rotation, viewpoint, zoom, and zoom-rotation changes, was analyzed. Images with the same resolution (750 × 500 pixels) were studied, in terms of correspondences, repeatability and computing time, and the correspondence was measured by using homographies i.e. projective transformations, to obtain the best efficiency for imaging applications. Results show that the multi-scale Harris Hessian detector is the most efficient for blur, illumination, and zoom-rotation changes. Meanwhile, multi-scale Hessian and Hessian Laplace are the best methods for rotation, viewpoint, and zoom changes.
Optics and Lasers in Engineering, 2013
In this work we introduce a 2-D Continuous Wavelet Transform (2-D CWT) method for denoising ESPI ... more In this work we introduce a 2-D Continuous Wavelet Transform (2-D CWT) method for denoising ESPI phase-maps. Multiresolution analysis with 2-D wavelets can provide high directional sensitivity and high anisotropy which are proper characteristics for this task. In particular, the 2-D CWT method using Gabor atoms (Gabor mother wavelets) which can naturally model phase fringes, has a good performance against noise and can preserve phase fringes. We describe the theoretical basis of the proposed technique and show some experimental results with real and simulated ESPI phase-maps. As can be verified the proposal is robust and effective.
Descripción: THE PRESENT PAPER PRESENTS THE COMPARISON OF A DECONVOLUTION ALGORITHM WITH OTHER TH... more Descripción: THE PRESENT PAPER PRESENTS THE COMPARISON OF A DECONVOLUTION ALGORITHM WITH OTHER THREE CLASSICAL APPROACHES FOR ONE-DIMENSIONAL DECONVOLUTION OF SIGNALS. THE ALGORITHM WAS ...
Journal of the European Optical Society: Rapid Publications, 2013
We introduce a new approach for image filtering in a Bayesian framework. In this case the probabi... more We introduce a new approach for image filtering in a Bayesian framework. In this case the probability density function (pdf) of the likelihood function is approximated using the concept of non-parametric or kernel estimation. The method is based on the generalized Gaussian Markov random fields (GGMRF), a class of Markov random fields which are used as prior information into the Bayesian rule, which principal objective is to eliminate those effects caused by the excessive smoothness on the reconstruction process of images which are rich in contours or edges. Accordingly to the hypothesis made for the present work, it is assumed a limited knowledge of the noise pdf, so the idea is to use a non-parametric estimator to estimate such a pdf and then apply the entropy to construct the cost function for the likelihood term. The previous idea leads to the construction of Maximum a posteriori (MAP) robust estimators, since the real systems are always exposed to continuous perturbations of unknown nature. Some promising results of three new MAP entropy estimators (MAPEE) for image filtering are presented, together with some concluding remarks.
A biased bootstrap technique is presented to obtain robust parameter and measurement estimates. M... more A biased bootstrap technique is presented to obtain robust parameter and measurement estimates. Moreover, the estimation of a measurement probability density function (pdf) using classical bootstrap techniques is presented as our final goal. Most of the time, large scale repetition of an experiment is not economically feasible, the Monte Carlo method cannot be used for uncertainty characterization and bootstrap methods are proved to be a potentially useful alternative. The measurement characterization is driven by the pdf estimation in a non-linear non-Gaussian case and with limited observed data.
A biased bootstrap technique is presented to obtain robust parameter and measurement estimates. M... more A biased bootstrap technique is presented to obtain robust parameter and measurement estimates. Moreover, the estimation of a measurement probability density function (pdf) using classical bootstrap techniques is presented as our final goal. Most of the time, large scale repetition of an experiment is not economically feasible, the Monte Carlo method cannot be used for uncertainty characterization and bootstrap methods are proved to be a potentially useful alternative. The measurement characterization is driven by the pdf estimation in a non-linear non-Gaussian case and with limited observed data.
2020 International Conference on Mechatronics, Electronics and Automotive Engineering (ICMEAE), 2020
A precise measurement in plants is necessary to know in detail the functions and processes of the... more A precise measurement in plants is necessary to know in detail the functions and processes of these living beings, which are a fundamental part for the development of life on the planet. The optimal growth conditions for any plant generated in a controlled atmosphere are very helpful to make measurements of the variable that may be the highest hierarchy: light. This paper describes the design of a growth sphere for optical measurements in plants (GSOMP), which fulfills two primary functions; generate the optimal conditions for the growth of the plant during its whole life cycle and perform incident light absorption measurements taking advantage of the geometric shape (spherical) and the coating of the device surface, so it is possible to obtain the light absorption spectrum in each phenological stage of any plant. Due to the aforementioned, this device is unique and represents a very useful option for research and experimentation in vegetables.
The correct phase unwrapping in the presence of noise is a difficult problem and it has been of g... more The correct phase unwrapping in the presence of noise is a difficult problem and it has been of great interest since the last decades as observed in the literature. This is due to the spatial dependency that exists in traditional 2-D phase-unwrapping algorithms and, as a consequence, spreads errors in the reconstructed phase map. To solve this, algorithms known as temporal phase unwrapping (TPU) have been proposed; here the intensity of a fringe image sequence changes as a function of time, and therefore the elements of the phase-map are independent of each other. Thus, the 3-D measurement vision system by projection of fringe images presented here consists in capturing a sequence of images with sinusoidal fringes deformed by the height of the object. Then, the phase is processed by using a TPU technique based the one-dimensional Continuous Wavelet Transform (CWT). It should be noted that the use of CWT in one dimension is to analyze the intensity variations of the temporal sampled ...
Wavelet Theory and Its Applications, Oct 3, 2018
Optical metrology and interferometry are widely known disciplines that study and develop techniqu... more Optical metrology and interferometry are widely known disciplines that study and develop techniques to measure physical quantities such as dimensions, force, temperature, stress, etc. A key part of these disciplines is the processing of interferograms, also called fringe patterns. Owing that this kind of images contains the information of interest in a codified form, processing them is of main relevance and has been a widely studied topic for many years. Several mathematical tools have been used to analyze fringe patterns, from the classic Fourier analysis to regularization methods. Some methods based on wavelet theory have been proposed for this purpose in the last years and have evidenced virtues to consider them as a good alternative for fringe pattern analysis. In this chapter, we resume the theoretical basis of fringe pattern image formation and processing, and some of the most relevant applications of the 2D continuous wavelet transform (CWT) in fringe pattern analysis.
Optics and Lasers in Engineering
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Papers by Ismael De la Rosa