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  • Optimization of digitization procedures in cultural heritage preservation

     Martínez Navarro, Beatriz; Mitja, Carles; Escofet Soteras, Jaume
    Iberoamerican Optics Meeting and Latin American Meeting on Optics, Lasers, and Applications.
    Presentation's date: 2013-07-20
    Presentation of work at congresses

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    The digitization of both volumetric and flat objects is the nowadays-preferred method in order to preserve cultural heritage items. High quality digital files obtained from photographic plates, films and prints, paintings, drawings, gravures, fabrics and sculptures, allows not only for a wider diffusion and on line transmission, but also for the preservation of the original items from future handling. Early digitization procedures used scanners for flat opaque or translucent objects and camera only for volumetric or flat highly texturized materials. The technical obsolescence of the high-end scanners and the improvement achieved by professional cameras has result in a wide use of cameras with digital back to digitize any kind of cultural heritage item. Since the lens, the digital back, the software controlling the camera and the digital image processing provide a wide range of possibilities, there is necessary to standardize the methods used in the reproduction work leading to preserve as high as possible the original item properties. This work presents an overview about methods used for camera system characterization, as well as the best procedures in order to identify and counteract the effect of the lens residual aberrations, sensor aliasing, image illumination, color management and image optimization by means of parametric image processing. As a corollary, the work shows some examples of reproduction workflow applied to the digitization of valuable art pieces and glass plate photographic black and white negatives.

  • View-through characterization of translucent fabrics based on opto-digital image analysis

     Escofet Soteras, Jaume; Mitja, Carles; Rallo Capdevila, Miguel; Millan Garcia Varela, Maria Sagrario
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2012
    Journal article

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  • Measuring image quality performance on image versions saved with different file format and compression ratio

     Mitja, Carles; Escofet Soteras, Jaume; Bover, Toni
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2012
    Journal article

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  • Determinació del factor de cobertura en teixits de calada per processament de la imatge digital i espectroscòpia de reflexió  Open access

     Tapias Anton, Montserrat
    Defense's date: 2012-06-08
    Department of Optics and Optometry, Universitat Politècnica de Catalunya
    Theses

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    In this thesis we applied, in a complementary way, techniques of digital image processing and reflectance spectroscopy to perform cover factor (CF) measurements in monochrome openwork fabrics. To evaluate the results provided by both techniques, we used the average CF obtained by a group of 18 expert observers as a reference. IMAGE PROCESSING PART: We developed a new, automatic and objective method for measuring both total and partial CF, and the width of the threads, from the digital image of the fabric. Two algorithms were developed for total and partial CF determinations. The image processing technique used to measure the total CF was the segmentation of the holes from the fabric threads. Conventional methods of segmentation did not lead to similar results than those of the total visual CF. Therefore, we designed a new algorithm (MSSQ) to measure the total CF of fabrics, independently of their degree of coverage. All the CF obtained in 81 typified textile samples were correlated with the CF obtained visually. The best fit to the Stevens' psychophysical law was achieved with the method MSSQ. These results were also consistent with the construction parameters of fabrics. The determination of partial CF in the warp and weft directions was performed by filtering in the Fourier space the warp and weft threads of the sample. For the design of these filters we applied the Radon transform to the power spectrum of the image of the fabric, in order to determine the direction of the warp and weft harmonics. The values of partial CF were consistent with the parameters that characterize the threads and were logical, expected and confirmed the robustness of the method. The values of the diameters of the threads were also consistent with the parameters of the yarn manufacturing and with the manual measurement performed on the image of the same fabric. This method is easily implementable in a laboratory of textile analysis. REFLECTANCE PART: We modelled the reflectance of a flat layer of fabric arranged on a support of known reflectance using the Kubelka-Munk theory. For this purpose we assumed that the optical behaviour of a layer of fabric could be determined by the superposition of two ideal elements: a neutral density filter with no thickness and with different values of transmittance depending on both the direction of the beam (input or output) and whether the beam passes through the covered part of the yarns or through the holes, plus a uniform and homogeneous layer of a material that meets the assumptions of the theory of Kubelka-Munk. The final model contained CF as a parameter. For a set of different samples of fabrics, the integrated spectral reflectance of a stack of increasing number of layers was experimentally measured with a spectroradiometer, up to stabilize the measure. The experimental reflectances were introduced in the generalized model to calculate the values of the parameters involved, particularly the CF. We solved the resulting system of 101 ¿ (m - 1) equations using the least squares method, where m is the total number of stacked layers of fabric, with 103 unknowns. This yielded a couple of estimates of CF. We established correlations between the measured CF (obtained as the solution of these equations) and the visual CF and analyzed the effect of perturbations in the reflectance measurements to explain the discrepancies between these two estimates of CF. Even if we observed problems of precision in one of the estimates and inaccuracy in the other, arising from an unknown parameter in the model, the intervention of the CF in the described model has been proven.

  • Measuring image quality in overlapping areas of panoramic composed images

     Mitja, Carles; Bover, Toni; Escofet Soteras, Jaume
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2012
    Journal article

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  • LCD displays performance comparison by MTF measurement using the white noise stimulus method

     Mitja, Carles; Escofet Soteras, Jaume
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2011-01-24
    Journal article

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    The amount of images produced to be viewed as soft copies on output displays are significantly increasing. This growing occurs at the expense of the images targeted to hard copy versions on paper or any other physical support. Even in the case of high quality hard copy production, people working in professional imaging uses different displays in selecting, editing, processing and showing images, from laptop screen to specialized high end displays. Then, the quality performance of these devices is crucial in the chain of decisions to be taken in image production. Metrics of this quality performance can help in the equipment acquisition. Different metrics and methods have been described to determine the quality performance of CRT and LCD computer displays in clinical area. One of most important metrics in this field is the device spatial frequency response obtained measuring the modulation transfer function (MTF). This work presents a comparison between the MTF of three different LCD displays, Apple MacBook Pro 15", Apple LED Cinema Display 24" and Apple iPhone4, measured by the white noise stimulus method, over vertical and horizontal directions. Additionally, different displays show particular pixels structure pattern. In order to identify this pixel structure, a set of high magnification images is taken from each display to be related with the respective vertical and horizontal MTF.

  • Automatic measurements of partial cover factors and yarn diameters in fabrics using image processing

     Tapias Anton, Montserrat; Rallo Capdevila, Miguel; Escofet Soteras, Jaume
    Textile research journal
    Date of publication: 2011-01
    Journal article

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  • Fotografia d'urbanisme: Anàlisis de la imatge fotogràfica en la comunicació visual d'un espai urbà.  Open access

     Bover Tanyà, Antoni
    Defense's date: 2011-11-29
    Department of Architectural Presentation I, Universitat Politècnica de Catalunya
    Theses

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    The image of the city is a collection of shapes and volumes in continuous evolution and transformation. Changes in the visual of the cities are appreciated on the long term, as it shape changes by the construction of new buildings and urban infrastructure. Techniques for graphic representation and visual communication of the city are also in continuous transformation, as science advances and technology that derives from it. Drawing graphic representation techniques improved with evolution on knowledge of geometric perspective and evolved with photography's birth. Throughout XX century, photography became the perfect graphic medium for representing urban areas, both to show the uniqueness of a formal space specifically to teach universal formal and loss of identity of most cities. The photographic image is immersed in recent years, in a major social, cultural and technological change. As we have developed devices and systems to capture a photographic image, the photographs bring more realism to the image and, therefore, better visual communication of a city. The fact of moving from a physical and chemical process to a physical and mathematical process to create a photographic image, allows us to create a quality and type of image that was unimaginable a few years ago. A particular feature of landscape photography are extension and size of the city as a photographic subject, which implies that the use of panoramic photography and visual tours with photographs provide a more complete, at least more representative, of the image of urban space. Another specific feature of landscape photography planning lies in the fact that the city and urban space are photographic subjects in constant evolution, which means that any photograph becomes historical photograph over time. Displays of old photographs, together with the view of the archaeological and architectural, are another way of understanding the past of the city. This thesis analyses landscape photography from the pedestrian's point of view, or from publicly accessible high points, and has analysed landscape photography's basic elements of visual communication that remain in the evolution of photochemical photography into digital photography and new elements bring by the emergence of digital photography in the visual communication of urban planning. Has been examined panoramic photography evolution to digital panoramic images from the fusion of multiple images and applications of these types of panoramic images to graphically represent the image of the city. Has been investigated other possibilities for old of urban planning photographs to explain the historical of the cities, to reformulate the concept of historical space from visual communication using historical photographs of urban spaces. The case analysis has not been taken as objectives a visual study of a particular city. Have been worked specific cases that can be extrapolated to other cities or urban spaces of any geographical area. Have been analysed aspects such concepts as previsualization, perspective or snapshot on panoramic photograph from the merge of photographs, and concept of what is real and what is not in the photograph.

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    Objective Measure of Woven Fabric's Cover Factor by Image Processing  Open access

     Tapias Anton, Montserrat; Rallo Capdevila, Miguel; Escofet Soteras, Jaume; Algaba Joaquín, Inés Mª; Riva Juan, Ascension
    Textile research journal
    Date of publication: 2010-01
    Journal article

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  • Matching rendered and real world images by digital image processing

     Mitja, Carles; Bover, Toni; Bigas, Miquel; Escofet Soteras, Jaume
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2010
    Journal article

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  • Unsupervised flaw segmentation in textile materials under visible and NIR illumination

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume; Rallo Capdevila, Miguel
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2010
    Journal article

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  • Relationships between lens performance and different sensor sizes in professional photographic still SLR cameras

     Mitja, Carles; Escofet Soteras, Jaume; Vega Lerin, Fidel
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2009-08-21
    Journal article

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    Current photographic still cameras, in the professional SLR step, are available in two basic sensor sizes, 16x24mm and 24x36mm and both of them can be used with the same or similar range of focal length lenses. Lens aperture determines resolving power and diffraction effects and indeed, MTF function. In order to preserve an acceptable image quality level, it must be taken into account that a high lens resolving power at larger apertures can be replicated by the sensor as a false response or aliasing, while the size of the Airy disc must be related with photo receptors pitch. Provided that a standardized metric of image quality is the system MTF, this work compares different lenses resolving power as a function of aperture with the lens and system MTF; both aliasing and resolution affectations can be observed in the system MTF. Lens resolving power has been measured by visual inspection of the aerial image of an USAF1951 test target through a suitable microscope. The lens PSF and MTF has been measured by means of a Shack-Hartmann optical wave front sensor. The system MTF is measured by the slanted edge method. The different experimental procedures have been applied to two professional SLR cameras equipped with the same general use lens.

  • Unsupervised novelty detection using Gabor filters for defect segmentation in textures

     Rallo Capdevila, Miguel; Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume
    Journal of the Optical Society of America A. Optics image science and vision
    Date of publication: 2009-01
    Journal article

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  • Image improvement in pinhole digital photography by means of inverse and Wienner filtering

     Mitja, Carles; Escofet Soteras, Jaume
    International Optical Congress "Optics XXI Century"
    Presentation's date: 2008-09-18
    Presentation of work at congresses

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    Optimal diameter based in PSF and MTF system measurement is determined for a pinhole camera. Optimal pinhole images are improved by deconvolution with previously estimated PSF and the result is compared with unsharp mask enhancement.

  • Flaw detection and segmentation in textile inspection (Vol. 7000 70000A)

     Millan Garcia Varela, Maria Sagrario; Miquel, Ralló; Rallo Capdevila, Miguel; Escofet Soteras, Jaume
    Photonics Europe 2008: Lasers and Photonics Applications
    Presentation of work at congresses

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    Implementation of the parametric representation of the Fourier transform in fabrics  Open access

     Cardenas, L. J.; Cifuentes, L.E; Torres, Y.; Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario
    Ingeniería y ciencia
    Date of publication: 2007-06
    Journal article

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  • Referenceless segmentation of flaws in woven fabrics

     Rallo Capdevila, Miguel; Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume
    Applied optics
    Date of publication: 2007-09
    Journal article

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  • Representación paramétrica de la Transformada de Fourier de tejidos textiles

     Cárdenas, L J; Cifuentes, L E; Torres, Y; Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario
    Ingeniería y ciencia
    Date of publication: 2007-06
    Journal article

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    Mesura automàtica i manual del factor de cobertura d¿un teixit mitjançant processat digital de la imatge  Open access

     Tapias Anton, Montserrat; Rallo Capdevila, Miguel; Escofet Soteras, Jaume
    Jornades de Conferències en Enginyeria Electrònica
    Presentation's date: 2006-11-01
    Presentation of work at congresses

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    Es defineix el factor de cobertura d¿un teixit com la relació entre l¿àrea coberta pels fils respecte de l¿àrea total del teixit. En aquest treball es presenten dos nous mètodes de mesura del factor de cobertura basats en la llindarització automàtica i manual d¿una imatge digital d¿un teixit. Els resultats obtinguts pels dos mètodes coincideixen amb un alt grau de fiabilitat.

  • Medida del sesgo de un tejido mediante la aplicación de la transformada de Radon al espacio frecuencial

     Escofet Soteras, Jaume; Tapias Anton, Montserrat; Rallo Capdevila, Miguel
    Reunión Nacional de Óptica
    Presentation's date: 2006-09-18
    Presentation of work at congresses

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  • Óptica geométrica. ejercicios de trazado gráfico de rayos

     Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Pérez Cabré, Elisabet; Cobo Ruiz, Fernando
    Date of publication: 2005-09-30
    Book

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  • Recursos multimedia para el aprendizaje de técnicas de trazado gráfico de rayos en un curso de óptica

     Cobo Ruiz, Fernando; Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Pérez Cabré, Elisabet
    Congrés Internacional de Docència Universitària i Innovació
    Presentation of work at congresses

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  • Mesura de la qualitat en la digitalització de col·leccions fotogràfiques

     Mitjà, C; Escofet Soteras, Jaume
    8es. Jornades Antoni Varés. Imatge i Recerca
    Presentation of work at congresses

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  • Automatización del cálculo del intervalo de error en las medidas realizadas en un laboratorio de óptica

     Cobo Ruiz, Fernando; Pérez Cabré, Elisabet; Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario
    Congrés Internacional de Docència Universitària i Innovació
    Presentation of work at congresses

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  • Optica geométrica

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume; Pérez Cabré, Elisabet
    Date of publication: 2004-02-28
    Book

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  • Fabric's cover factor measurement by image thresholding

     Tapias Anton, Montserrat; Rallo Capdevila, Miguel; Escofet Soteras, Jaume
    RIAO/OPTILAS 2004
    Presentation of work at congresses

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  • Inspection of fabrics with fluffy appearance by NIR image analysis

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume
    RIAO/OPTILAS 2004
    Presentation of work at congresses

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  • NIR imaging of non-uniform colored webs. Application to fabric inspection

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume
    RIAO/OPTILAS 2004
    Presentation of work at congresses

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  • Mesura de la qualitat en la digitalització de col·leccions fotogràfiques

     Mitjà, C; Escofet Soteras, Jaume
    8es. Jornades Antoni Varés. Imatge i Recerca
    Presentation of work at congresses

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  • Fabric inspection by near-infrared machine vision

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume
    Optics letters
    Date of publication: 2004-07
    Journal article

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  • Medida de la FTM en cámara fotográficas digitales

     Mitjà, C; Escofet Soteras, Jaume
    Reunión Nacional de Óptica
    Presentation of work at congresses

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  • Determinación del factor de cobertura de un tejido mediante segmentación de su histograma

     Tapias Anton, Montserrat; Escofet Soteras, Jaume; Rallo Capdevila, Miguel
    Reunión Nacional de Óptica
    Presentation of work at congresses

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  • Segmentación automática de defectos en tejidos mediante filtrado en el espacio de Fourier

     Rallo Capdevila, Miguel; Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario
    Reunión Nacional de Óptica
    Presentation of work at congresses

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  • Weave-repeat identification by structural analysis of fabric images

     Rallo Capdevila, Miguel; Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario
    Applied optics
    Date of publication: 2003-06
    Journal article

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  • Optical angular correlation in Fourier domain

     Millan Garcia Varela, Maria Sagrario; Pérez Cabré, Elisabet; Escofet Soteras, Jaume; Garcia Campello, Jesus Maria
    Journal of modern optics
    Date of publication: 2003-06
    Journal article

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  • Propuesta de equipamiento científico-tecnológico

     Millan Garcia Varela, Maria Sagrario; Vega Lerin, Fidel; Elisabet, Pérez; Armengol Cebrian, Jesús; Escofet Soteras, Jaume
    Date: 2002-10
    Report

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  • Wavelet based techniques for textile inspection

     Rallo Capdevila, Miguel; Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume; Navarro, R
    Wavelets and Applications, International Workshop
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  • Extracción de características de color y de textura en imágenes de muestras textiles no uniformes

     Escofet Soteras, Jaume; Navarro, R; Nestares, O; Millan Garcia Varela, Maria Sagrario; Corbalán Fuertes, Montserrat
    Congreso Nacional de Color
    Presentation's date: 2002
    Presentation of work at congresses

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  • Dispositivo y procedimientos de visión por ordenador para la medida y caracterización del color en una muestra

     Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Navarro, R; Nestares, O
    Date of request: 2002-04-26
    Invention patent

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    Dispositivo y procedimientos de visión por ordenador para la medida y caracterización de la distribución de color en una muestra.

    El sistema está indicado para medir el color y caracterizar su distribución espacial en muestras no uniformes. Se compone de las unidades de iluminación, captación de la imagen, digitalización, almacenamiento, procesado digital y presentación de imagen y resultados. La imagen digital en color de entrada, en sus componentes RGB, es sometida a un procedimiento de análisis que permite obtener los colores predominantes, con especificación de sus coordenadas cromáticas en los sistemas colorimétricos estándar. Los colores dominantes, así como el porcentaje de área que ocupan, se visualizan en la pantalla del monitor. La caracterización se complementa con el cálculo de momentos estadísticos de primer, segundo, tercero y cuarto orden. El grado de aproximación es ajustable mediante la selección del número de colores dominantes que se desea considerar. Como opción el sistema permite segmentar la imagen en relación con la información del color, asignando a cada área su color dominante.

  • Specification and identification of woven patterns based on Fourier techniques

     Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Miquel, Ralló; Rallo Capdevila, Miguel
    IV Reunión Iberoamericana de Optica, VII Encuentro Latinoamericano de Optica, Láseres y sus Aplicaciones
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  • Modeling of woven fabric structures based on Fourier image analysis

     Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Miquel, Ralló; Rallo Capdevila, Miguel
    Applied optics
    Date of publication: 2001-12
    Journal article

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  • Caracterització, reconeixement de patrons i detecció de defectes en textures periòdiques mitjançant anàlisi d'imatges. Aplicació a teixits textils  Open access

     Escofet Soteras, Jaume
    Defense's date: 1999-11-26
    Department of Optics and Optometry, Universitat Politècnica de Catalunya
    Theses

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    La forta exigència de qualitat a que són sotmesos els productes actuals fa que els processos d'inspecció i control industrial ocupin, cada vegada més, un lloc destacat en la seva fabricació. La indústria relacionada amb els materials de superfície texturada i periòdica (malles metàl·liques, plàstics, paper, làmines, roba, etc.) no és aliena a aquest problema i, en l'actualitat, està esmerçant molts esforços en aquest camp. Un cas representatiu dels materials anteriors, que presenta una ampla problemàtica en quan a inspecció i control així com una elevada exigència de qualitat en l'acabat, és el teixit tèxtil.La majoria de defectes que es produeixen en el procés productiu d'un material tèxtil, com en tants altres materials i productes industrials, són detectats encara per inspectors humans. La seva feina és, en general, molt repetitiva i rutinària i, moltes vegades, el consum de temps que hi dediquen és molt elevat. A més cal fixar l'atenció en petits detalls situats en un camp extens, que sovint es troba en moviment, el que acaba produint fatiga visual en l'operari.En les últimes dècades, gràcies al gran desenvolupament tecnològic que hi ha hagut, estem assistint a una sèrie d'avenços, molt ràpids i de gran abast, en el món dels processos d'automatització i control. A conseqüència d'això, cada vegada el procés de producció és més ràpid, el que requereix que el control de qualitat també ho sigui.L'interès industrial en automatitzar les operacions d'inspecció és cada vegada més gran. A tall d'exemple la fira tèxtil internacional que reuneix més interès i expectació a nivell mundial, ITMA-99, celebrada aquest any a París, mostrava en els seus stands diferents productes dedicats a l'automatització dels processos d'inspecció i control de qualitat. Entre les ofertes d'aquesta fira cal citar una gran varietat d'instruments i dispositius: sensors òptics per inspeccionar la qualitat del fil en temps real en processos de filatura, espectrecolorímetres acoblats a l'estampadora i a la màquina de tintar per determinar amb més precisió el color, cameres lineals i cameres 2-D ultraràpides per detectar fils trencats en ordidors. En el camp del tissatge s'ha començat a veure en aquesta fira un sistema d'inspecció format per un conjunt (10 o 12) de cameres 2-D, situades damunt del teler, que detecta defectes locals que es poden produir en la roba durant el procés de producció. Des de la penúltima fira (ITMA-94) ha sigut novetat una màquina de repassar automàtica, on un sistema digital de processat format per 4 cameres i un potent ordinador, permet detectar una més ampla varietat de defectes locals i amb una velocitat nominal que pot arribar fins a 300 metres de roba per minut. Malgrat tot, les novetats aportades per la fira presenten grans limitacions: preu elevat, infrastructura complexa en la captació i processat de la imatge i, els resultats que s'obtenen només han estat validats per casos limitats (teixit de plana i d'un sol color). A més, si es té en compte que molts processos de producció són de tirada curta, canviant constantment el tipus d'article del teler, es necessita un sistema que sigui robust i versàtil, capaç de treballar amb diferents lligaments i colors i que el seu cost sigui més baix que el dels productes actuals.Revisant la última dècada, la més rellevant en el desenvolupament d'aquestes tecnologies, s'observa un clar increment en l'aplicació de tècniques de processat digital de la imatge a l'anàlisi de mostres texturades [Brzakovic-1992]. En el cas de la inspecció de materials tèxtils Chetverikov [Chetverikov-1988] desenvolupà un procés d'inspecció automàtica en teixits tèxtils que combina l'anàlisi de textures i la segmentació d'imatges. Neubauer [Neubauer-1992] segmentà defectes en mostres reals amb l'ajut d'una camera lineal i una xarxa neuronal. Siew et al. [Siew-1988] mesuraren les característiques texturals en catifes a partir d'estadístiques de primer i segon ordre aplicades als nivells de grisos de la imatge. Zhang i Bresse [Zhang-1995] detectaren i classificaren nusos, carreres i trencades mitjançant l'autocorrelació i operacions de morfologia matemàtica. Tsai et al. [Tsai-1995] detectaren i classificaren exactament quatre classes de defectes en teixits tèxtils utilitzant matrius de co-ocurrència i xarxes neuronals. Xu [Xu-1997] mesurà la rugositat en les superfícies de catifes a partir de la dimensió fractal de la imatge. Mitjançant tècniques combinades de filtrat Gaussià, umbralització, equalització de l'histograma i autocorrelació Kang et al. [Kang-1999] determinaren densitats lineals de fils en els direccions de trama i ordit per teixits de plana.La inspecció de materials texturats quasiperiòdics i, en particular els tèxtils, mitjançant tècniques de processat òptic-digital de la imatge és un camp d'investigació relativament poc treballat i que presenta un interès renovat. En aquest apartat es troben poques contribucions entre les que cal destacar Kang et al. [Kang-1999] que trobaven directament, a partir de la llum transmesa pel teixit, el punt de creuament dels fils en teixits de plana i Ciamberlini [Ciamberlini-1996] que operava amb la TF òptica de la llum transmesa pel teixit.Les eines que actualment estan al mercat són insuficients i es centren principalment en la resolució d'un aspecte: la detecció de defectes locals. En la literatura no és troben plantejaments generals que abastin des de models i procediments per caracteritzar les estructures fins a mecanismes que determinin la seva evolució o resistència davant d'agressions, la detecció de defectes globals en l'estructura i la detecció de defectes locals. Creiem que aquest plantejament general, que pot ser vàlid per a una gran varietat de materials, és també necessari. En aquest treball s'han aplicat, principalment a materials tèxtils, un conjunt d'eines inspirades en aquest plantejament.

  • Introducción a los instrumentos ópticos

     Escofet Soteras, Jaume; Pérez Cabré, Elisabet; Millan Garcia Varela, Maria Sagrario
    Date of publication: 1999-05-31
    Book

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  • Detection of local defects in textile webs using Gabor filters

     Pladellorens Mallofre, Josep; Escofet Soteras, Jaume; Navarro, Rafael; Millan Garcia Varela, Maria Sagrario
    Optical engineering
    Date of publication: 1998-08
    Journal article

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  • Control de calidad en tejidos textiles mediante procesado de imagen

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume; Abril Baez, Hector C.
    Reunión Iberoamericana de Óptica (RIAO) y Encuentro Latinoamaricano de Óptica, Láseres y Aplicaciones (OPTILAS)
    Presentation of work at congresses

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  • Medida de la distorsión de un tejido mediante análisis frecuencial de imágenes

     Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Abril Baez, Hector C.
    Reunión Iberoamericana de Óptica (RIAO) y Encuentro Latinoamaricano de Óptica, Láseres y Aplicaciones (OPTILAS)
    Presentation of work at congresses

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  • Medida de la distorsión de un tejido mediante análisis frecuencial de imágenes

     Escofet Soteras, Jaume
    Reunión Iberoamericana de Óptica (RIAO) y Encuentro Latinoamaricano de Óptica, Láseres y Aplicaciones (OPTILAS)
    Presentation's date: 1998-09-26
    Presentation of work at congresses

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  • Inspection of fabric resistance to Abrasion by Fourier analysis

     Escofet Soteras, Jaume; Millan Garcia Varela, Maria Sagrario; Abril Baez, Hector C.; Torrecilla, E
    Optics in Computing OC'98
    Presentation of work at congresses

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  • Automatic quality control of textile webs by image processing

     Millan Garcia Varela, Maria Sagrario; Escofet Soteras, Jaume; Abril Baez, Hector C.; Navarro, R; Torres, Y
    Reunión Iberoamericana de Óptica (RIAO) y Encuentro Latinoamaricano de Óptica, Láseres y Aplicaciones (OPTILAS)
    Presentation of work at congresses

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