|
|
Debora Gil, & Petia Radeva. (2004). "Shape Restoration via a Regularized Curvature Flow " . Journal of Mathematical Imaging and Vision, 21(3), 205–223.
Abstract: Any image filtering operator designed for automatic shape restoration should satisfy robustness (whatever the nature and degree of noise is) as well as non-trivial smooth asymptotic behavior. Moreover, a stopping criterion should be determined by characteristics of the evolved image rather than dependent on the number of iterations. Among the several PDE based techniques, curvature flows appear to be highly reliable for strongly noisy images compared to image diffusion processes.
In the present paper, we introduce a regularized curvature flow (RCF) that admits non-trivial steady states. It is based on a measure of the local curve smoothness that takes into account regularity of the curve curvature and serves as stopping term in the mean curvature flow. We prove that this measure decreases over the orbits of RCF, which endows the method with a natural stop criterion in terms of the magnitude of this measure. Further, in its discrete version it produces steady states consisting of piece-wise regular curves. Numerical experiments made on synthetic shapes corrupted with different kinds of noise show the abilities and limitations of each of the current geometric flows and the benefits of RCF. Finally, we present results on real images that illustrate the usefulness of the present approach in practical applications.
|
|
|
|
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.
|
|
|
|
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, .
|
|
|
|
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.
|
|
|
|
Ernest Valveny, & Enric Marti. (2003). "A model for image generation and symbol recognition through the deformation of lineal shapes " . Pattern Recognition Letters, 24(15), 2857–2867.
Abstract: We describe a general framework for the recognition of distorted images of lineal shapes, which relies on three items: a model to represent lineal shapes and their deformations, a model for the generation of distorted binary images and the combination of both models in a common probabilistic framework, where the generation of deformations is related to an internal energy, and the generation of binary images to an external energy. Then, recognition consists in the minimization of a global energy function, performed by using the EM algorithm. This general framework has been applied to the recognition of hand-drawn lineal symbols in graphic documents.
|
|
|
|
Oriol Rodriguez-Leor, J. Mauri, Eduard Fernandez-Nofrerias, M. Gomez, Antonio Tovar, L. Cano, et al. (2002)." Ecografia Intracoronaria: Segmentacio Automatica de area de la llum" . Revista Societat Catalana de Cardiologia, 4(4), 42.
|
|
|
|
Josep Llados, Enric Marti, & Juan J.Villanueva. (2001). "Symbol recognition by error-tolerant subgraph matching between region adjacency graphs " . IEEE Transactions on Pattern Analysis and Machine Intelligence, 23(10), 1137–1143.
Abstract: The recognition of symbols in graphic documents is an intensive research activity in the community of pattern recognition and document analysis. A key issue in the interpretation of maps, engineering drawings, diagrams, etc. is the recognition of domain dependent symbols according to a symbol database. In this work we first review the most outstanding symbol recognition methods from two different points of view: application domains and pattern recognition methods. In the second part of the paper, open and unaddressed problems involved in symbol recognition are described, analyzing their current state of art and discussing future research challenges. Thus, issues such as symbol representation, matching, segmentation, learning, scalability of recognition methods and performance evaluation are addressed in this work. Finally, we discuss the perspectives of symbol recognition concerning to new paradigms such as user interfaces in handheld computers or document database and WWW indexing by graphical content.
|
|
|
|
Ernest Valveny, & Enric Marti. (2000). "Deformable Template Matching within a Bayesian Framework for Hand-Written Graphic Symbol Recognition " . Graphics Recognition Recent Advances, 1941, 193–208.
Abstract: We describe a method for hand-drawn symbol recognition based on deformable template matching able to handle uncertainty and imprecision inherent to hand-drawing. Symbols are represented as a set of straight lines and their deformations as geometric transformations of these lines. Matching, however, is done over the original binary image to avoid loss of information during line detection. It is defined as an energy minimization problem, using a Bayesian framework which allows to combine fidelity to ideal shape of the symbol and flexibility to modify the symbol in order to get the best fit to the binary input image. Prior to matching, we find the best global transformation of the symbol to start the recognition process, based on the distance between symbol lines and image lines. We have applied this method to the recognition of dimensions and symbols in architectural floor plans and we show its flexibility to recognize distorted symbols.
|
|
|
|
Josep Llados, & Enric Marti. (1999)." A graph-edit algorithm for hand-drawn graphical document recognition and their automatic introduction into CAD systems" . Machine Graphics & Vision, 8, 195–211.
|
|
|
|
Josep Llados, & Enric Marti. (1999)." Graph-edit algorithms for hand-drawn graphical document recognition and their automatic introduction" . Machine Graphics & Vision journal, special issue on Graph transformation, .
|
|
