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Author Aura Hernandez-Sabate; Debora Gil; Josefina Mauri; Petia Radeva
Title Reducing cardiac motion in IVUS sequences Type Conference Article
Year 2006 Publication Proceeding of Computers in Cardiology Abbreviated Journal
Volume 33 Issue Pages 685-688
Keywords
Abstract Cardiac vessel displacement is a main artifact in IVUS sequences. It hinders visualization of the main structures in an appropriate orientation and alignment and affects extracting vessel measurements. In this paper, we present a novel approach for image sequence alignment based on spectral analysis, which removes rigid dynamics, preserving at the same time the vessel geometry. First, we suppress the translation by taking, for each frame, the center of mass of the image as origin of coordinates. In polar coordinates with such point as origin, the rotation appears as a horizontal displacement. The translation induces a phase shift in the Fourier coefficients of two consecutive polar images. We estimate the phase by adjusting a regression plane to the phases of the principal frequencies. Experiments show that the presented strategy suppress cardiac motion regardless of the acquisition device. 1.
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Notes IAM; MILAB Approved no
Call Number IAM @ iam @ HGM2006a Serial 1554
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Author Aura Hernandez-Sabate; Debora Gil; Petia Radeva; E.N.Nofrerias
Title Anisotropic processing of image structures for adventitia detection in intravascular ultrasound images Type Conference Article
Year 2004 Publication Proc. Computers in Cardiology Abbreviated Journal
Volume 31 Issue Pages 229-232
Keywords
Abstract The adventitia layer appears as a weak edge in IVUS images with a non-uniform grey level, which difficulties its detection. In order to enhance edges, we apply an anisotropic filter that homogenizes the grey level along the image significant structures (ridges, valleys and edges). A standard edge detector applied to the filtered image yields a set of candidate points prone to be unconnected. The final model is obtained by interpolating the former line segments along the tangent direction to the level curves of the filtered image with an anisotropic contour closing technique based on functional extension principles
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Corporate Author Thesis
Publisher Place of Publication Chicago (USA) Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes IAM; MILAB Approved no
Call Number IAM @ iam @ HGR2004 Serial 1555
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Author Ole Vilhelm-Larsen; Petia Radeva; Enric Marti
Title Guidelines for choosing optimal parameters of elasticity for snakes Type Book Chapter
Year 1995 Publication Computer Analysis Of Images And Patterns Abbreviated Journal LNCS
Volume 970 Issue Pages 106-113
Keywords
Abstract This paper proposes a guidance in the process of choosing and using the parameters of elasticity of a snake in order to obtain a precise segmentation. A new two step procedure is defined based on upper and lower bounds on the parameters. Formulas, by which these bounds can be calculated for real images where parts of the contour may be missing, are presented. Experiments on segmentation of bone structures in X-ray images have verified the usefulness of the new procedure.
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Publisher Place of Publication Editor
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Series Editor Series Title Lecture Notes in Computer Science Abbreviated Series Title LNCS
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Area Expedition Conference
Notes MILAB;IAM Approved no
Call Number IAM @ iam @ LRM1995b Serial 1558
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Author Ole Larsen; Petia Radeva; Enric Marti
Title Bounds on the optimal elasticity parameters for a snake Type Journal Article
Year 1995 Publication Image Analysis and Processing Abbreviated Journal
Volume Issue Pages 37-42
Keywords
Abstract This paper develops a formalism by which an estimate for the upper and lower bounds for the elasticity parameters for a snake can be obtained. Objects different in size and shape give rise to different bounds. The bounds can be obtained based on an analysis of the shape of the object of interest. Experiments on synthetic images show a good correlation between the estimated behaviour of the snake and the one actually observed. Experiments on real X-ray images show that the parameters for optimal segmentation lie within the estimated bounds.
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Publisher Place of Publication Editor
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Area Expedition Conference
Notes MILAB;IAM Approved no
Call Number IAM @ iam @ LRM1995a Serial 1559
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Author Ole Larsen; Petia Radeva; Enric Marti
Title Calculating the Bounds on the Optimal Parameters of Elasticity for a Snake Type Report
Year 1994 Publication Technical Report Abbreviated Journal
Volume Issue Pages
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Abstract
Address Aalborg University
Corporate Author Thesis
Publisher Aalborg University, Laboratory of image Analysis. Place of Publication Denmark Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Aalborg University, Laboratory of image Analysis. Expedition Conference
Notes MILAB;IAM Approved no
Call Number IAM @ iam @ LRM1994 Serial 1560
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Author Jaime Lopez-Krahe; Josep Llados; Enric Marti
Title Architectural Floor Plan Analysis Type Report
Year 2000 Publication CVonline Abbreviated Journal
Volume Issue Pages
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Abstract
Address Edimburg, UK
Corporate Author Thesis
Publisher University of Edinburgh Place of Publication Editor Robert B. Fisher
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium online pdf
Area Expedition Conference
Notes DAG;IAM Approved no
Call Number IAM @ iam @ LLM2000 Serial 1561
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Author Josep Llados; Horst Bunke; Enric Marti
Title Finding rotational symmetries by cyclic string matching Type Journal Article
Year 1997 Publication Pattern recognition letters Abbreviated Journal PRL
Volume 18 Issue 14 Pages 1435-1442
Keywords Rotational symmetry; Reflectional symmetry; String matching
Abstract Symmetry is an important shape feature. In this paper, a simple and fast method to detect perfect and distorted rotational symmetries of 2D objects is described. The boundary of a shape is polygonally approximated and represented as a string. Rotational symmetries are found by cyclic string matching between two identical copies of the shape string. The set of minimum cost edit sequences that transform the shape string to a cyclically shifted version of itself define the rotational symmetry and its order. Finally, a modification of the algorithm is proposed to detect reflectional symmetries. Some experimental results are presented to show the reliability of the proposed algorithm
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Publisher Elsevier Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes DAG;IAM; Approved no
Call Number IAM @ iam @ LBM1997a Serial 1562
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Author Josep Llados;Horst Bunke; Enric Marti
Title Using Cyclic String Matching to Find Rotational and Reflectional Symmetries in Shapes Type Conference Article
Year 1997 Publication Intelligent Robots: Sensing, Modeling and Planning Abbreviated Journal
Volume Issue Pages 164-179
Keywords
Abstract Dagstuhl Workshop
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Corporate Author Thesis
Publisher World Scientific Press Place of Publication Editor
Language (down) Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 9810231857 Medium
Area Expedition Conference
Notes DAG;IAM; Approved no
Call Number IAM @ iam @ LBM1997b Serial 1563
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Author Josep Llados; Horst Bunke; Enric Marti
Title Using cyclic string matching to find rotational and reflectional symmetric shapes Type Conference Article
Year 1996 Publication Dagstuhl Seminar on Modelling and Planning for Sensor–based Intelligent Robot Systems Abbreviated Journal
Volume Issue Pages
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Abstract
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Corporate Author Thesis
Publisher World Scientific Place of Publication Saarbrucken (Germany). Editor R.C. Bolles, H.B.H.N.
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Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes DAG;IAM Approved no
Call Number IAM @ iam @ LBM1996 Serial 1564
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Author Josep Llados; Horst Bunke; Enric Marti
Title Structural Recognition of hand drawn floor plans Type Conference Article
Year 1996 Publication VI National Symposium on Pattern Recognition and Image Analysis Abbreviated Journal
Volume Issue Pages
Keywords Rotational Symmetry; Reflectional Symmetry; String Matching.
Abstract A system to recognize hand drawn architectural drawings in a CAD environment has been deve- loped. In this paper we focus on its high level interpretation module. To interpret a floor plan, the system must identify several building elements, whose description is stored in a library of pat- terns, as well as their spatial relationships. We propose a structural approach based on subgraph isomorphism techniques to obtain a high-level interpretation of the document. The vectorized input document and the patterns to be recognized are represented by attributed graphs. Discrete relaxation techniques (AC4 algorithm) have been applied to develop the matching algorithm. The process has been divided in three steps: node labeling, local consistency and global consistency verification. The hand drawn creation causes disturbed line drawings with several accuracy errors, which must be taken into account. Here we have identified them and the AC4 algorithm has been adapted to manage them.
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Corporate Author Thesis
Publisher Place of Publication Cordoba Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes DAG;IAM; Approved no
Call Number IAM @ iam @ LIM1995 Serial 1565
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Author Josep Llados; Jaime Lopez-Krahe; Enric Marti
Title A system to understand hand-drawn floor plans using subgraph isomorphism and Hough transform Type Book Chapter
Year 1997 Publication Machine Vision and Applications Abbreviated Journal
Volume 10 Issue 3 Pages 150-158
Keywords Line drawings – Hough transform – Graph matching – CAD systems – Graphics recognition
Abstract Presently, man-machine interface development is a widespread research activity. A system to understand hand drawn architectural drawings in a CAD environment is presented in this paper. To understand a document, we have to identify its building elements and their structural properties. An attributed graph structure is chosen as a symbolic representation of the input document and the patterns to recognize in it. An inexact subgraph isomorphism procedure using relaxation labeling techniques is performed. In this paper we focus on how to speed up the matching. There is a building element, the walls, characterized by a hatching pattern. Using a straight line Hough transform (SLHT)-based method, we recognize this pattern, characterized by parallel straight lines, and remove from the input graph the edges belonging to this pattern. The isomorphism is then applied to the remainder of the input graph. When all the building elements have been recognized, the document is redrawn, correcting the inaccurate strokes obtained from a hand-drawn input.
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Area Expedition Conference
Notes DAG;IAM Approved no
Call Number IAM @ iam @ LLM1997a Serial 1566
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Author Josep Llados; Jaime Lopez-Krahe; Gemma Sanchez; Enric Marti
Title Interprétation de cartes et plans par mise en correspondance de graphes de attributs Type Conference Article
Year 2000 Publication 12 Congrès Francophone AFRIF–AFIA Abbreviated Journal
Volume 3 Issue Pages 225-234
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Abstract
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Area Expedition Conference RFIA
Notes DAG;IAM Approved no
Call Number IAM @ iam @ LLS2000 Serial 1567
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Author Josep Llados; Enric Marti
Title A graph-edit algorithm for hand-drawn graphical document recognition and their automatic introduction into CAD systems Type Journal Article
Year 1999 Publication Machine Graphics & Vision Abbreviated Journal
Volume 8 Issue Pages 195-211
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Abstract
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Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes DAG;IAM; Approved no
Call Number IAM @ iam @ LIM1999 Serial 1568
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Author Josep Llados; Enric Marti
Title Graph-edit algorithms for hand-drawn graphical document recognition and their automatic introduction Type Journal Article
Year 1999 Publication Machine Graphics & Vision journal, special issue on Graph transformation Abbreviated Journal
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Abstract
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Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes DAG;IAM Approved no
Call Number IAM @ iam @ LIM1999c Serial 1569
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Author Josep Llados; Enric Marti
Title Playing with error-tolerant subgraph isomorphism in line drawings Type Conference Article
Year 1997 Publication VII National Symposium on Pattern Recognition and image Analysis Abbreviated Journal
Volume Issue Pages
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Abstract
Address
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Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes DAG;IAM; Approved no
Call Number IAM @ iam @ LlM1997 Serial 1570
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