Fast Method Based on Fuzzy Logic for Gaussian-Impulsive Noise Reduction in CT Medical Images

To remove Gaussian-impulsive mixed noise in CT medical images, a parallel filter based on fuzzy logic is applied. The used methodology is structured in two steps. A method based on a fuzzy metric is applied to remove the impulsive noise at the first step. To reduce Gaussian noise, at the second step, a fuzzy peer group filter is used on the filtered image obtained at the first step. A comparative analysis with state-of-the-art methods is performed on CT medical images using qualitative and quantitative measures evidencing the effectiveness of the proposed algorithm. The parallel method is parallelized on shared memory multiprocessors. After applying parallel computing strategies, the obtained computing times indicate that the introduced filter enables to reduce Gaussian-impulse mixed noise on CT medical images in real-time.This research was funded by the Spanish Ministry of Science, Innovation and Universities (Grant RTI2018-098156-B-C54), and it was co-financed with FEDER funds

Newton additive and multiplicative Schwarz iterative methods

Convergence properties are presented for Newton additive and multiplicative Schwarz (AS and MS) iterative methods for the solution of nonlinear systems in several variables. These methods consist of approximate solutions of the linear Newton step using either AS or MS iterations, where overlap between subdomains can be used. Restricted versions of these methods are also considered. These Schwarz methods can also be used to precondition a Krylov subspace method for the solution of the linear Newton steps. Numerical experiments on parallel computers are presented, indicating the effectiveness of these methods.The Spanish Ministry of Science and Education (TIN2005-09037-C02-02); Universidad de Alicante (VIGROB-020); the U.S. Department of Energy (DE-FG02-05ER25672)

El discurso matemático del profesor: ejemplos, explicaciones y coherencia local

Se examina el discurso matemático de un profesor a lo largo de una discusión de clase, con inspiración en el marco MDI –Mathematical Discourse in Instruction. Se interpretan momentos de selección y secuenciación de ejemplos y explicaciones durante la resolución del problema del reparto de una apuesta en un juego interrumpido. Para ello, aplicamos una noción de coherencia local que alude al cumplimiento de condiciones sobre la selección, secuenciación y conexión de ejemplos y explicaciones. Se concluye que la coherencia local del discurso es mayor en los momentos en los cuales se aportan ejemplos con una función refutadora y desestabilizadora del razonamiento proporcional inicialmente utilizado por los alumnos, y a la vez explicaciones con una función modeladora hacia el concepto de probabilidad que se pretende introducir

Matemática Discreta en las Ingenierías en Informática

La Matemática Discreta es una especialidad relativamente joven, que está cobrando más fuerza a medida que van pasando los años. Tres ejes se están desarrollando fuertemente: la Teoría de los Números en especial sus aplicaciones criptográficas, la Lógica, y por supuesto la Teoría de los grafos cuyos campos de aplicación van desde los químicos hasta los electrónicos, pasando por los economistas. Presentamos unas tablas resumiendo los créditos, contenidos y bibliografía de la asignatura. Proponemos un breve análisis de los contenidos impartidos en la asignatura Matemática Discreta en 25 Universidades Españolas, para intentar tener una visión del panorama nacional

Review of the early Albian ammonites of the Montmell Formation near Marmellar (Salou-Garraf Basin, Tarragona, Catalonia, Spain)

In this work, we review the ammonites of the Montmell Formation in the Marmellar area housed in the collections of the Museo Geológico del Seminario de Barcelona and the Museu de Geologia de Barcelona. This taxonomic update allows the proper biostratigraphic analysis of the ammonite assemblage and assigns it to the early Albian, Leymeriella tardefurcata Zone. The taxonomic analysis of all the studied material allows us to recognize the presence of the following taxa: Uhligella sp., Parengonoceras bassei, Hypacanthoplites plesiotypicus, Hypacanthoplites milletianus, Hypacanthoplites subelegans, and Hypacanthoplites sp. The current work is a step forward in the chronostratigraphic knowledge of the Salou-Garraf Basin in the Catalan Coastal Ranges

On the detection of defects on specular car body surfaces

[EN] The automatic detection of small defects (of up to 0.2 mm in diameter) on car body surfaces following the painting process is currently one of the greatest issues facing quality control in the automotive industry. Although several systems have been developed during the last decade to provide a solution to this problem, these, to the best of our knowledge, have been focused solely on flat surfaces and have been unable to inspect other parts of the surfaces, namely style lines, edges and corners as well as deep concavities. This paper introduces a novel approach using deflectometry- and vision-based technologies in order to overcome this problem and ensure that the whole area is inspected. Moreover, since our approach, together with the system used, computes defects in less than 15 s, it satisfies cycle time production requirements (usually of around 30 s per car). Hence, a two-step algorithm is presented here: in the first step, a new pre-processing step (image fusion algorithm) is introduced to enhance the contrast between pixels with a low level of intensity (indicating the presence of defects) and those with a high level of intensity (indicating the absence of defects); for the second step, we present a novel post-processing step with an image background extraction approach based on a local directional blurring method and a modified image contrast enhancement, which enables detection of defects in the entire illuminated area. In addition, the post-processing step is processed several times using a multi-level structure, with computed image backgrounds of different resolution. In doing so, it is possible to detect larger defects, given that each level identifies defects of different sizes. Experimental results presented in this paper are obtained from the industrial automatic quality control system QEyeTunnel employed in the production line at the Mercedes-Benz factory in Vitoria, Spain. A complete analysis of the algorithm performance will be shown here, together with several tests proving the robustness and reliability of our proposal.This work is supported by VALi+d (APOSTD/2016/044) and PROMETEO (PROMETEOII/2014/044) Programs, both from Conselleria d'Educacio, Generalitat Valenciana.Molina, J.; Solanes Galbis, JE.; Arnal-Benedicto, L.; Tornero Montserrat, J. (2017). On the detection of defects on specular car body surfaces. Robotics and Computer-Integrated Manufacturing. 48:263-278. https://doi.org/10.1016/j.rcim.2017.04.009S2632784

Detecting dings and dents on specular car body surfaces based on optical flow

[EN] This paper introduces a new approach to detect defects cataloged as dings and dents on car body surfaces, which is currently one of the most important issues facing quality control in the automotive industry. Using well-known optical flow algorithms and the deflectometry principle, the method proposed in this work is able to detect all kind of anomalies on specular surfaces. Hence, our method consists of two main steps: first, in the pre-processing step, light patterns projected on the body surface sweep uniformly the area of inspection, whilst a new image fusion law, based on optical flow, is used to obtain a resulting fused image holding the information of all variations suffered by the projected patterns during the sweeping process, indicating the presence of anomalies; second, a new post-processing step is proposed that avoids the need of using pre-computed reference backgrounds in order to differentiate defects from other body features such as style-lines. To that end, the image background of the resulting fused image is estimated in the first place through a method based on blurring the image according to the direction of each pixel. Afterwards, the estimated image background is used in a new subtraction law through which defects are well differentiated from other surface deformations, allowing the detection of defects in the entire illuminated area. In addition, since our approach, together with the system used, computes defects in less than 15 s, it satisfies the assembly plants time requirements. Experimental results presented in this paper are obtained from the industrial automatic quality control system QEyeTunnel employed in the production line at the Mercedes-Benz factory in Vitoria, Spain. A complete analysis of the algorithm performance will be shown here, together with several tests proving the robustness and reliability of our proposal.This work is supported by VALi+d (APOSTD/2016/044) and PROMETEO (PROMETEOII/2014/044) Programs, both from Conselleria d'Educacio, Generalitat Valenciana.Arnal-Benedicto, L.; Solanes Galbis, JE.; Molina, J.; Tornero Montserrat, J. (2017). Detecting dings and dents on specular car body surfaces based on optical flow. Journal of Manufacturing Systems. 45:306-321. https://doi.org/10.1016/j.jmsy.2017.07.006S3063214

Analysis of FPGA filter in computed tomography images for radioactive dose reduction

[EN] X-Ray or CT (computed tomography) images may have noise due to image acquisition process. As contaminated images complicate diagnosis many filters have been developed to overcome this problem. In this work we study the behavior of a Fuzzy method called FPGA, which detect and correct impulsive and Gaussian noise, used over a medical image obtained from the mini-MIAS database that has been altered with impulsive and/or Gaussian noise. The aim of the study is verify if FPGA is a candidate to be used as a method to reduce the radiation dose in CT. Results show that FPGA outperforms the rest of the methods studied and it reveals itself as a good candidate to be employed in CT images to reduce the radiation dose.[ES] Las imágenes de Rayos-X o de tomografía computarizada (CT) pueden contener ruido debido al proceso de adquisición. Este ruido complica sustancialmente el proceso diagnóstico, por lo que será necesario el desarrollo de filtros efectivos. En este trabajo se estudia el comportamiento del filtro Fuzzy Peer Group Averaging (Fuzzy PGA) sobre una colección de imágenes mamográficas que ha sido previamente contaminada con ruido impulsivo y gaussiano. El objetivo del trabajo es averiguar si Fuzzy PGA es adecuado para la mejora de imágenes CT obtenidas con una dosis de radiación reducida. Los resultados indican que Fuzzy PGA se comporta, efectivamente, mejor que el resto de métodos estudiados en este trabajo y por tanto resulta un candidato adecuado.Parcero Iglesias, E.; Vidal Gimeno, VE.; Verdú Martín, GJ.; Arnal García, J. (2014). Analysis of FPGA filter in computed tomography images for radioactive dose reduction. Grupo Senda. http://hdl.handle.net/10251/49701

Corals on the slope (Aptian, Maestrat Basin, Spain)

The term "reef" has been frequently misused when applied to fossil coral communities. Our popular but biased view of coral community structure based on the idyllic picture of recent tropical reefs has failed to recognize that, in many fossil examples, alternative states of community structure with no or limited framework may occur. The Aptian colonial scleractinians analysed in the western Maestrat Basin (eastern Spain) constitute an example of non-reef-building coral populations, which thrived in marly slope settings. These corals developed within the photic zone but below the storm wave-base. All colonies are found well-preserved in life position. They are mostly decimetres in size and mainly occur isolated giving rise to a continuous and uniform (dominated by domal and massive forms) unbound growth fabric with a low to medium degree of development (coral skeletal volume = 5-20%). Occasionally, however, colonies growing on top of each other forming small metre-sized bioherms are also present. A total of 21 species were identified. Coral diversity in each sample location varies between three and nine species. These numbers of species are comparable with those exhibited by coeval coral assemblages from other basins of the Tethys, but are comparatively low when compared with diversities exhibited by many Recent and fossil coral communities. The corals studied apparently found optimal ecological conditions for their development on the marly slopes of the western Maestrat Basin. This is primarily expressed in the unusually large dimensions (up to 2.3 m in width) of some of the coral colonies when compared to other Cretaceous occurrences, and in the persistence and resilience of the coral populations. The observed coral genera and species (suborders Archeocaeniina, Faviina, Fungiina and Microsolenina) are very common in the time interval between the Barremian and the Early Albian and most of them have been reported from several other localities in the western and central Tethyan realm. In addition, the coral-bearing levels also contain the poorly known and exotic genera Agrostyliastraea and Procladocora. There are no significant differences at species level or in community structure between the Early and Late Aptian faunas investigated. Therefore, the coral communities as well as the environmental conditions controlling them would have been relatively stable during the time intervals when these corals flourished. An important palaeoecological implication is that comparatively low species diversities and the absence of reef frameworks do not necessarily imply unfavourable environmental conditions for coral growth. Furthermore, this study may serve as an example for the analysis of other level-bottom coral communities displaying a loose growth fabric