| Records |
| Author |
Aura Hernandez-Sabate; Debora Gil; Albert Teis |
| Title |
How Do Conservation Laws Define a Motion Suppression Score in In-Vivo Ivus Sequences? |
Type |
Conference Article |
| Year |
2007 |
Publication |
Proc. IEEE Ultrasonics Symp |
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
2231-2234 |
| Keywords |
validation standards; IVUS motion compensation; conservation laws. |
| Abstract |
Evaluation of arterial tissue biomechanics for diagnosis and treatment of cardiovascular diseases is an active research field in the biomedical imaging processing area. IntraVascular UltraSound (IVUS) is a unique tool for such assessment since it reflects tissue morphology and deformation. A proper quantification and visualization of both properties is hindered by vessel structures misalignments introduced by cardiac dynamics. This has encouraged development of IVUS motion compensation techniques. However, there is a lack of an objective evaluation of motion reduction ensuring a reliable clinical application This work reports a novel score, the Conservation of Density Rate (CDR), for validation of motion compensation in in-vivo pullbacks. Synthetic experiments validate the proposed score as measure of motion parameters accuracy; while results in in vivo pullbacks show its reliability in clinical cases. |
| 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 |
Approved |
no |
| Call Number |
IAM @ iam @ HTG2007 |
Serial |
1550 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| Author |
Aura Hernandez-Sabate; Debora Gil; J. 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
| |
|
| |
| 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 |
| Permanent link to this record |
