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Oriol Rodriguez-Leor, Debora Gil, Eduard Fernandez-Nofrerias, H. Tizon, S. Montserrat, Vicente del Valle, et al. (2007). Caracterització de la Perfusió Miocàrdica mitjançant anàlisi estadístic de l espectre en l angiografia de contrast. In XIX Congrés de la Societat Catalana de Cardiologia de Barcelona (130). Barcelona (Spain).
Abstract: La valoració de la integritat de la microcirculació coronària aporta informació pronòstica en pacients amb infart agut de miocardi en els que es realitza angioplastia primària. Aquesta valoració és subjectiva i presenta una important variabilitat si no es duta a terme per personal experimentat. Presentem una eina d’anàlisi d’imatge que permet fer una valoració de la microcirculació coronària a partir de seqüències d’angiografia. Hem analitzat les variacions locals en el nivell de gris de la imatge durant la seqüència angiogràfica. Hem identificat els principals fenòmens observats (respiració, batec cardíac, tinció arterial, tinció miocàrdica i soroll radiològic) mitjançant un anàlisi estadístic de l’espectre de Fourier de l’evolució al llarg del temps de la mitja local. Aquest mateix anàlisis permet determinat la influència de cadascun d’ells en la extracció del patró de tinció i selecciona la respiració com el fenomen que més distorsiona el patró de tinció original. Els descriptors proposats s’obtenen fora del rang espectral respiratori. Hem testat la seva capacitat per a detectar els tres fenòmens principals (tinció miocàrdica (MS), tinció arterial (AS) i soroll (NS)) independentment de la respiració. La capacitat de discriminació dels descriptors ha estat valorada mitjançant un mètode de crossvalidation en 30 seqüències d’angiografia. Els descriptors emprats permeten caracteritzar la tinció miocàrdica amb una alta eficiència i fiabilitat. A més no hi ha diferències significatives en l’anàlisi de les seqüències obtingudes amb el pacient respirant amb normalitat o en apnea
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Oriol Rodriguez-Leor, Debora Gil, & Eduard Fernandez-Nofrerias. (2006). Analisis en los cambios en el nivel de gris en las secuencias angiograficas mediante descriptores estadisticos para determinar la perfusion miocardica. REC - Revista Española de Cardiología, 59 Supl 2-166(2), 128.
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Oriol Rodriguez-Leor, J. Mauri, Eduard Fernandez-Nofrerias, C. Garcia, R. Villuendas, Vicente del Valle, et al. (2003). Reconstruction of a spatio-temporal model of the intima layer from intravascular ultrasound sequences. European Heart Journal, .
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Oriol Rodriguez-Leor, J. Mauri, Eduard Fernandez-Nofrerias, Antonio Tovar, Vicente del Valle, Aura Hernandez-Sabate, et al. (2004). Utilización de la Estructura de los Campos Vectoriales para la Detección de la Adventicia en Imágenes de Ecografía Intracoronaria. Revista Internacional de Enfermedades Cardiovasculares Revista Española de Cardiología, 57(2), 100.
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Oriol Rodriguez-Leor, Eduard Fernandez-Nofrerias, J. Mauri, Vicente del Valle, Debora Gil, A.Barrios, et al. (2006). Perfusion ratio: A new tool to objectively assess microcirculation perfusion after primary Percutaneous Coronary Intervention. In World Congress of Cardiology (859). Barcelona (Spain).
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Oriol Rodriguez-Leor, J. Mauri, Eduard Fernandez-Nofrerias, Vicente de Valle, E. Garcia, A. Barrios, et al. (2006). Analysis of the changes in angiography local grey-level values to determine myocardial perfusion. In World Congress of Cardiology (862). Barcelona (Spain).
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Misael Rosales, Petia Radeva, Oriol Rodriguez-Leor, & Debora Gil. (2009). Modelling of image-catheter motion for 3-D IVUS. MIA - Medical image analysis, 13(1), 91–104.
Abstract: Three-dimensional intravascular ultrasound (IVUS) allows to visualize and obtain volumetric measurements of coronary lesions through an exploration of the cross sections and longitudinal views of arteries. However, the visualization and subsequent morpho-geometric measurements in IVUS longitudinal cuts are subject to distortion caused by periodic image/vessel motion around the IVUS catheter. Usually, to overcome the image motion artifact ECG-gating and image-gated approaches are proposed, leading to slowing the pullback acquisition or disregarding part of IVUS data. In this paper, we argue that the image motion is due to 3-D vessel geometry as well as cardiac dynamics, and propose a dynamic model based on the tracking of an elliptical vessel approximation to recover the rigid transformation and align IVUS images without loosing any IVUS data. We report an extensive validation with synthetic simulated data and in vivo IVUS sequences of 30 patients achieving an average reduction of the image artifact of 97% in synthetic data and 79% in real-data. Our study shows that IVUS alignment improves longitudinal analysis of the IVUS data and is a necessary step towards accurate reconstruction and volumetric measurements of 3-D IVUS.
Keywords: Intravascular ultrasound (IVUS); Motion estimation; Motion decomposition; Fourier
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David Rotger, Misael Rosales, Jaume Garcia, Oriol Pujol, J. Mauri, & Petia Radeva. (2003). Active Vessel: A New Multimedia Workstation for Intravascular Ultrasound and Angiography Fusion. Computers in Cardiology, 30, 65–68.
Abstract: AcriveVessel is a new multimedia workstation which enables the visualization, acquisition and handling of both image modalities, on- and ofline. It enables DICOM v3.0 decompression and browsing, video acquisition,repmduction and storage for IntraVascular UltraSound (IVUS) and angiograms with their corresponding ECG,automatic catheter segmentation in angiography images (using fast marching algorithm). BSpline models definition for vessel layers on IVUS images sequence and an extensively validated tool to fuse information. This approach defines the correspondence of every IVUS image with its correspondent point in the angiogram and viceversa. The 3 0 reconstruction of the NUS catheterhessel enables real distance measurements as well as threedimensional visualization showing vessel tortuosity in the space.
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F. Javier Sanchez, Jordi Vitria, & Enric Marti. (1991). Transformaciones Morfológicas de Polígonos Isotéticos. In Primer Congreso Español de Informática Gráfica..
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Gemma Sanchez, Josep Llados, & Enric Marti. (1997). Segmentation and analysis of linial texture in plans. In Intelligence Artificielle et Complexité.. Paris.
Abstract: The problem of texture segmentation and interpretation is one of the main concerns in the field of document analysis. Graphical documents often contain areas characterized by a structural texture whose recognition allows both the document understanding, and its storage in a more compact way. In this work, we focus on structural linial textures of regular repetition contained in plan documents. Starting from an atributed graph which represents the vectorized input image, we develop a method to segment textured areas and recognize their placement rules. We wish to emphasize that the searched textures do not follow a predefined pattern. Minimal closed loops of the input graph are computed, and then hierarchically clustered. In this hierarchical clustering, a distance function between two closed loops is defined in terms of their areas difference and boundary resemblance computed by a string matching procedure. Finally it is noted that, when the texture consists of isolated primitive elements, the same method can be used after computing a Voronoi Tesselation of the input graph.
Keywords: Structural Texture, Voronoi, Hierarchical Clustering, String Matching.
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Gemma Sanchez, Ernest Valveny, Josep Llados, Enric Marti, Oriol Ramos Terrades, N.Lozano, et al. (2003). A system for virtual prototyping of architectural projects. In Proceedings of Fifth IAPR International Workshop on Pattern Recognition (pp. 65–74).
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Joan Serrat, & Enric Marti. (1991). Elastic matching using interpolation splines. In IV Spanish Symposium of Pattern Recognition and image Analysis.
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Elena Valderrama, Joan Oliver, Josep Maria-Basart, Enric Marti, Petia Radeva, Ricardo Toledo, et al. (2005). Convergencia al EEES de la ingeniería informática. Título de Grado en tecnología (Informática).
Abstract: Elena Valderrama
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Ernest Valveny, & Enric Marti. (2001). Learning of structural descriptions of graphic symbols using deformable template matching. In Proc. Sixth Int Document Analysis and Recognition Conf (pp. 455–459).
Abstract: Accurate symbol recognition in graphic documents needs an accurate representation of the symbols to be recognized. If structural approaches are used for recognition, symbols have to be described in terms of their shape, using structural relationships among extracted features. Unlike statistical pattern recognition, in structural methods, symbols are usually manually defined from expertise knowledge, and not automatically infered from sample images. In this work we explain one approach to learn from examples a representative structural description of a symbol, thus providing better information about shape variability. The description of a symbol is based on a probabilistic model. It consists of a set of lines described by the mean and the variance of line parameters, respectively providing information about the model of the symbol, and its shape variability. The representation of each image in the sample set as a set of lines is achieved using deformable template matching.
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Ernest Valveny, & Enric Marti. (2000). Hand-drawn symbol recognition in graphic documents using deformable template matching and a Bayesian framework. In Proc. 15th Int Pattern Recognition Conf (Vol. 2, pp. 239–242).
Abstract: Hand-drawn symbols can take many different and distorted shapes from their ideal representation. Then, very flexible methods are needed to be able to handle unconstrained drawings. We propose here to extend our previous work in hand-drawn symbol recognition based on a Bayesian framework and deformable template matching. This approach gets flexibility enough to fit distorted shapes in the drawing while keeping fidelity to the ideal shape of the symbol. In this work, we define the similarity measure between an image and a symbol based on the distance from every pixel in the image to the lines in the symbol. Matching is carried out using an implementation of the EM algorithm. Thus, we can improve recognition rates and computation time with respect to our previous formulation based on a simulated annealing algorithm.
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