Image-A : Applicable Mathematics in Image Engineering - 2013 - Vol. III, Nº 5
URI permanente para esta colecciónhttps://hdl.handle.net/11441/2594
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Artículo DGCI 2013 Demo Session 7th IAPR International Conference on Discrete Geometry for Computer Imagery. Foreword(2013) Díaz Pernil, Daniel; Fondón García, Irene; González Díaz, Rocío; Jiménez Rodríguez, María José; Universidad de Sevilla. Departamento de Matemática Aplicada I; Universidad de Sevilla. Departamento de Teoría de la Señal y ComunicacionesArtículo Calibration in optical graph recognition(Universidad de Sevilla, 2013) Auer, Christopher; Bachmaier, Christian; Brandenburg, Franz J.; Gleißner, AndreasGraph drawing is the process of transforming the topological structure of a graph into a graphical representation. Primarily, it maps vertices to points and displays them by icons, and it maps edges to Jordan curves connecting the endpoints. Optical graph recognition (OGR) is the inverse and transforms the digital image of a drawn graph into its topological structure. It consists of four phases: preprocessing, segmentation, topology recognition, and postprocessing. OGR is based on established digital image processing techniques. Its novelty is the topology recognition where the edges are recognized with emphasis on the attachment to their vertices and on edge crossings. Our prototypical implementation OGRup shows the effectiveness of the approach and produces a GraphML file, which can be used for further algorithmic studies and graph drawing tools. It has been tested both on hand made graph drawings and on drawings generated by graph drawing algorithms. Here we report on experiments for the calibration of parameters, which are critical for topology recognition.Artículo TKDetection: a software to detect and segment wood knots(Universidad de Sevilla, 2013) henbühl, Adrien; Kerautret, Bertrand; Debled-Rennesson, IsabelleTKDetection is a software proposing to segment the wood knots obtained from X-Ray Computed Tomography (CT) scanners. It implements algorithms combining tools of image analysis and discrete geometry, like connected component extraction, contour extraction or dominant point detection. TKDetection is the first free and open source software for the automatic knot segmentation. It is available on Github platform.Artículo Reconstructing persistent graph structures from noisy images(Universidad de Sevilla, 2013) Chernov, Alexey; Kurlin, VitaliyLet a point cloud be a noisy dotted image of a graph on the plane. We present a new fast algorithm for reconstructing the original graph from the given point cloud. Degrees of vertices in the graph are found by methods of persistent topology. Necessary parameters are automatically optimized by machine learning tools.Artículo Regular map smoothing(Universidad de Sevilla, 2013) Razafindrazaka, Faniry; Polthier, KonradA regular map is a family of equivalent polygons, glued together to form a closed surface without boundaries which is vertex, edge and face transitive. The commonly known regular maps are derived from the Platonic solids and some tessellations of the torus. There are also regular maps of genus greater than 1 which are traditionally viewed as finitely generated groups. RMS (Regular Map Smoothing) is a tool for visualizing a geometrical realization of such a group either as a cut-out in the hyperbolic space or as a compact surface in 3−space. It provides also a tool to make the resulting regular map more appealing than before. RMS achieves that by the use of a coloring scheme based on coset enumeration, a Catmull-Clark smoothing scheme and a force-directed algorithm with topology preservation.Artículo Implementation of Integral based Digital Curvature Estimators in DGtal(Universidad de Sevilla, 2013) Coeurjolly, David; Lachaud, Jacques-Olivier; Levallois, JérémyIn many geometry processing applications, differential geometric quantities estimation such as curvature or normal vector field is an essential step. In [1], we have defined curvature estimators on digital shape boundaries based on Integral Invariants. In this paper, we focus on implementation details of these estimators.