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	Author	Aura Hernandez-Sabate; Monica Mitiko; Sergio Shiguemi; Debora Gil
	Title	A validation protocol for assessing cardiac phase retrieval in IntraVascular UltraSound			Type	Conference Article
	Year	2010	Publication	Computing in Cardiology	Abbreviated Journal
	Volume	37	Issue		Pages	899-902
	Keywords
	Abstract	A good reliable approach to cardiac triggering is of utmost importance in obtaining accurate quantitative results of atherosclerotic plaque burden from the analysis of IntraVascular UltraSound. Although, in the last years, there has been an increase in research of methods for retrospective gating, there is no general consensus in a validation protocol. Many methods are based on quality assessment of longitudinal cuts appearance and those reporting quantitative numbers do not follow a standard protocol. Such heterogeneity in validation protocols makes faithful comparison across methods a difficult task. We propose a validation protocol based on the variability of the retrieved cardiac phase and explore the capability of several quality measures for quantifying such variability. An ideal detector, suitable for its application in clinical practice, should produce stable phases. That is, it should always sample the same cardiac cycle fraction. In this context, one should measure the variability (variance) of a candidate sampling with respect a ground truth (reference) sampling, since the variance would indicate how spread we are aiming a target. In order to quantify the deviation between the sampling and the ground truth, we have considered two quality scores reported in the literature: signed distance to the closest reference sample and distance to the right of each reference sample. We have also considered the residuals of the regression line of reference against candidate sampling. The performance of the measures has been explored on a set of synthetic samplings covering different cardiac cycle fractions and variabilities. From our simulations, we conclude that the metrics related to distances are sensitive to the shift considered while the residuals are robust against fraction and variabilities as far as one can establish a pair-wise correspondence between candidate and reference. We will further investigate the impact of false positive and negative detections in experimental data.
	Address
	Corporate Author				Thesis
	Publisher	IEEE	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0276-6547	ISBN	978-1-4244-7318-2	Medium
	Area		Expedition		Conference	CINC
	Notes	IAM;			Approved	no
	Call Number	IAM @ iam @ HSM2010			Serial	1551
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	Author	Aura Hernandez-Sabate; Petia Radeva; Antonio Tovar; Debora Gil
	Title	Vessel structures alignment by spectral analysis of ivus sequences			Type	Conference Article
	Year	2006	Publication	Proc. of CVII, MICCAI Workshop	Abbreviated Journal
	Volume		Issue		Pages	39-36
	Keywords
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Copenhaguen (Denmark),	Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title	1st International Wokshop on Computer Vision for Intravascular and Intracardiac Imaging (CVII’06)	Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes	IAM; MILAB			Approved	no
	Call Number	IAM @ iam @ HRT2006			Serial	1552
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	Author	Aura Hernandez-Sabate; David Rotger; Debora Gil
	Title	Image-based ECG sampling of IVUS sequences			Type	Conference Article
	Year	2008	Publication	Proc. IEEE Ultrasonics Symp. IUS 2008	Abbreviated Journal
	Volume		Issue		Pages	1330-1333
	Keywords	Longitudinal Motion; Image-based ECG-gating; Fourier analysis
	Abstract	Longitudinal motion artifacts in IntraVascular UltraSound (IVUS) sequences hinders a properly 3D reconstruction and vessel measurements. Most of current techniques base on the ECG signal to obtain a gated pullback without the longitudinal artifact by using a specific hardware or the ECG signal itself. The potential of IVUS images processing for phase retrieval still remains little explored. In this paper, we present a fast forward image-based algorithm to approach ECG sampling. Inspired on the fact that maximum and minimum lumen areas are related to end-systole and end-diastole, our cardiac phase retrieval is based on the analysis of tissue density of mass along the sequence. The comparison between automatic and manual phase retrieval (0.07 ± 0.07 mm. of error) encourages a deep validation contrasting with ECG signals.
	Address	Beijing (China)
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	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 @ HRG2008			Serial	1553
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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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	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 @ 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
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Chicago (USA)	Editor
	Language		Summary Language		Original Title
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title	Lecture Notes in Computer Science	Abbreviated Series Title	LNCS
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	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
	Keywords
	Abstract
	Address	Aalborg University
	Corporate Author				Thesis
	Publisher	Aalborg University, Laboratory of image Analysis.	Place of Publication	Denmark	Editor
	Language		Summary Language		Original Title
	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
	Keywords
	Abstract
	Address	Edimburg, UK
	Corporate Author				Thesis
	Publisher	University of Edinburgh	Place of Publication		Editor	Robert B. Fisher
	Language		Summary Language		Original Title
	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
	Address
	Corporate Author				Thesis
	Publisher	Elsevier	Place of Publication		Editor
	Language		Summary Language		Original Title
	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
	Address
	Corporate Author				Thesis
	Publisher	World Scientific Press	Place of Publication		Editor
	Language		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
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	World Scientific	Place of Publication	Saarbrucken (Germany).	Editor	R.C. Bolles, H.B.H.N.
	Language		Summary Language		Original Title
	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 @ 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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Cordoba	Editor
	Language		Summary Language		Original Title
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	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 @ 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
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	RFIA
	Notes	DAG;IAM			Approved	no
	Call Number	IAM @ iam @ LLS2000			Serial	1567
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