M.Gomez, J.Mauri, E.Fernandez-Nofrerias, O.Rodriguez-Leor,, C.Julia, et al. (2002). Una nova aplicacio informatica per a la correlacio d imatges angiografiques i d ecografia intracoronaria. Revista de la Societat Catalana de Cardiologia, 4(4): 42, XIV Congres de la Societat Catalana de Cardiologia..
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Debora Gil, & Petia Radeva. (2004). A Regularized Curvature Flow Designed for a Selective Shape Restoration. IEEE Transactions on Image Processing, 13, 1444–1458.
Abstract: Among all filtering techniques, those based exclu- sively on image level sets (geometric flows) have proven to be the less sensitive to the nature of noise and the most contrast preserving. A common feature to existent curvature flows is that they penalize high curvature, regardless of the curve regularity. This constitutes a major drawback since curvature extreme values are standard descriptors of the contour geometry. We argue that an operator designed with shape recovery purposes should include a term penalizing irregularity in the curvature rather than its magnitude. To this purpose, we present a novel geometric flow that includes a function that measures the degree of local irregularity present in the curve. A main advantage is that it achieves non-trivial steady states representing a smooth model of level curves in a noisy image. Performance of our approach is compared to classical filtering techniques in terms of quality in the restored image/shape and asymptotic behavior. We empirically prove that our approach is the technique that achieves the best compromise between image quality and evolution stabilization.
Keywords: Geometric flows, nonlinear filtering, shape recovery.
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Carlo Gatta, Juan Diego Gomez, Francesco Ciompi, O. Rodriguez-Leor, & Petia Radeva. (2009). Toward robust myocardial blush grade estimation in contrast angiography. In 4th Iberian Conference on Pattern Recognition and Image Analysis (Vol. 5524, 249–256). LNCS. Springer Berlin Heidelberg.
Abstract: The assessment of Myocardial Blush Grade after primary angioplasty is a precious diagnostic tool to understand if the patient needs further medication or the use of specifics drugs. Unfortunately, the assessment of MBG is difficult for non highly specialized staff. Experimental data show that there is poor correlation between MBG assessment of low and high specialized staff, thus reducing its applicability. This paper proposes a method able to achieve an objective measure of MBG, or a set of parameters that correlates with the MBG. The method tracks the blush area starting from just one single frame tagged by the physician. As a consequence, the blush area is kept isolated from contaminating phenomena such as diaphragm and arteries movements. We also present a method to extract four parameters that are expected to correlate with the MBG. Preliminary results show that the method is capable of extracting interesting information regarding the behavior of the myocardial perfusion.
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David Guillamet, M. Bressan, & Jordi Vitria. (2001). Weighted Non-negative Matrix Factorization for Local Representations..
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Carlo Gatta, Simone Balocco, Francesco Ciompi, R. Hemetsberger, O. Rodriguez-Leor, & Petia Radeva. (2010). Real-time gating of IVUS sequences based on motion blur analysis: Method and quantitative validation. In 13th international conference on Medical image computing and computer-assisted intervention (Vol. II, pp. 59–67). Springer-Verlag Berlin.
Abstract: Intravascular Ultrasound (IVUS) is an image-guiding technique for cardiovascular diagnostic, providing cross-sectional images of vessels. During the acquisition, the catheter is pulled back (pullback) at a constant speed in order to acquire spatially subsequent images of the artery. However, during this procedure, the heart twist produces a swinging fluctuation of the probe position along the vessel axis. In this paper we propose a real-time gating algorithm based on the analysis of motion blur variations during the IVUS sequence. Quantitative tests performed on an in-vitro ground truth data base shown that our method is superior to state of the art algorithms both in computational speed and accuracy.
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Carlo Gatta, & Petia Radeva. (2009). Bilateral Enhancers. In 16th IEEE International Conference on Image Processing (pp. 3161–3165).
Abstract: Ten years ago the concept of bilateral filtering (BF) became popular in the image processing community. The core of the idea is to blend the effect of a spatial filter, as e.g. the Gaussian filter, with the effect of a filter that acts on image values. The two filters acts on orthogonal domains of a picture: the 2D lattice of the image support and the intensity (or color) domain. The BF approach is an intuitive way to blend these two filters giving rise to algorithms that perform difficult tasks requiring a relatively simple design. In this paper we extend the concept of BF, proposing the bilateral enhancers (BE). We show how to design proper functions to obtain an edge-preserving smoothing and a selective sharpening. Moreover, we show that the proposed algorithm can perform edge-preserving smoothing and selective sharpening simultaneously in a single filtering.
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E Fernandez-Nofrerias, J. Mauri, A. Tovar, L. Cano, E. Martinez, C. Julia, et al. (2001). Correspondencia de las imagenes de angiografia y ecografia intracoronaria: La fusion..
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Alicia Fornes, Sergio Escalera, Josep Llados, & Ernest Valveny. (2010). Symbol Classification using Dynamic Aligned Shape Descriptor. In 20th International Conference on Pattern Recognition (1957–1960).
Abstract: Shape representation is a difficult task because of several symbol distortions, such as occlusions, elastic deformations, gaps or noise. In this paper, we propose a new descriptor and distance computation for coping with the problem of symbol recognition in the domain of Graphical Document Image Analysis. The proposed D-Shape descriptor encodes the arrangement information of object parts in a circular structure, allowing different levels of distortion. The classification is performed using a cyclic Dynamic Time Warping based method, allowing distortions and rotation. The methodology has been validated on different data sets, showing very high recognition rates.
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Alicia Fornes, Sergio Escalera, Josep Llados, Gemma Sanchez, & Joan Mas. (2008). Hand Drawn Symbol Recognition by Blurred Shape Model Descriptor and a Multiclass Classifier. In J.M. Ogier J. L. W. Liu (Ed.), Graphics Recognition: Recent Advances and New Opportunities (Vol. 5046, 30–40). LNCS.
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Alicia Fornes, Sergio Escalera, Josep Llados, & Gemma Sanchez. (2007). Symbol Recognition by Multi-class Blurred Shape Models. In Seventh IAPR International Workshop on Graphics Recognition (11–13).
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Alicia Fornes, Sergio Escalera, Josep Llados, Gemma Sanchez, Petia Radeva, & Oriol Pujol. (2007). Handwritten Symbol Recognition by a Boosted Blurred Shape Model with Error Correction. In 3rd Iberian Conference on Pattern Recognition and Image Analysis (IbPRIA 2007), J. Marti et al. (Eds.) LNCS 4477:13–21.
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Miquel Ferrer, Robert Benavente, Ernest Valveny, J. Garcia, Agata Lapedriza, & Gemma Sanchez. (2008). Aprendizaje Cooperativo Aplicado a la Docencia de las Asignaturas de Programacion en Ingenieria Informatica.
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Sergio Escalera, David M.J. Tax, Oriol Pujol, Petia Radeva, & Robert P.W. Duin. (2008). Subclass Problem-Dependent Design for Error-Correcting Output Codes. IEEE Trans. on Pattern Analysis and Machine Intelligence, vol.30(6):1041–1054.
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Sergio Escalera, & Petia Radeva. (2004). Fast greyscale road sign model matching and recognition.
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Sergio Escalera. (2008). Coding and Decoding Design of ECOCs for Multi-Class Pattern and Object Recognition.
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