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| Author | David Roche; Debora Gil; Jesus Giraldo | ||||
| Title | Mechanistic analysis of the function of agonists and allosteric modulators: Reconciling two-state and operational models | Type | Journal Article | ||
| Year | 2013 | Publication | British Journal of Pharmacology | Abbreviated Journal | BJP |
| Volume | 169 | Issue | 6 | Pages | 1189-202 |
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| Abstract | Two-state and operational models of both agonism and allosterism are compared to identify and characterize common pharmacological parameters. To account for the receptor-dependent basal response, constitutive receptor activity is considered in the operational models. By arranging two-state models as the fraction of active receptors and operational models as the fractional response relative to the maximum effect of the system, a one-by-one correspondence between parameters is found. The comparative analysis allows a better understanding of complex allosteric interactions. In particular, the inclusion of constitutive receptor activity in the operational model of allosterism allows the characterization of modulators able to lower the basal response of the system; that is, allosteric modulators with negative intrinsic efficacy. Theoretical simulations and overall goodness of fit of the models to simulated data suggest that it is feasible to apply the models to experimental data and constitute one step forward in receptor theory formalism. | ||||
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Notes  |
IAM; 600.044; 605.203 | Approved | no | ||
| Call Number | IAM @ iam @ RGG2013b | Serial | 2195 | ||
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| Author | David Roche; Debora Gil; Jesus Giraldo | ||||
| Title | Detecting loss of diversity for an efficient termination of EAs | Type | Conference Article | ||
| Year | 2013 | Publication | 15th International Symposium on Symbolic and Numeric Algorithms for Scientific Computing | Abbreviated Journal | |
| Volume | Issue | Pages | 561 - 566 | ||
| Keywords | EA termination; EA population diversity; EA steady state | ||||
| Abstract | Termination of Evolutionary Algorithms (EA) at its steady state so that useless iterations are not performed is a main point for its efficient application to black-box problems. Many EA algorithms evolve while there is still diversity in their population and, thus, they could be terminated by analyzing the behavior some measures of EA population diversity. This paper presents a numeric approximation to steady states that can be used to detect the moment EA population has lost its diversity for EA termination. Our condition has been applied to 3 EA paradigms based on diversity and a selection of functions
covering the properties most relevant for EA convergence. Experiments show that our condition works regardless of the search space dimension and function landscape. |
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| Address | Timisoara; Rumania; | ||||
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| ISSN | ISBN | 978-1-4799-3035-7 | Medium | ||
| Area | Expedition | Conference | SYNASC | ||
| Notes |
IAM; 600.044; 600.060; 605.203 | Approved | no | ||
| Call Number | Admin @ si @ RGG2013c | Serial | 2299 | ||
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| Author | Debora Gil; Agnes Borras; Sergio Vera; Miguel Angel Gonzalez Ballester | ||||
| Title | A Validation Benchmark for Assessment of Medial Surface Quality for Medical Applications | Type | Conference Article | ||
| Year | 2013 | Publication | 9th International Conference on Computer Vision Systems | Abbreviated Journal | |
| Volume | 7963 | Issue | Pages | 334-343 | |
| Keywords | Medial Surfaces; Shape Representation; Medical Applications; Performance Evaluation | ||||
| Abstract | Confident use of medial surfaces in medical decision support systems requires evaluating their quality for detecting pathological deformations and describing anatomical volumes. Validation in the medical imaging field is a challenging task mainly due to the difficulties for getting consensual ground truth. In this paper we propose a validation benchmark for assessing medial surfaces in the context of medical applications. Our benchmark includes a home-made database of synthetic medial surfaces and volumes and specific scores for evaluating surface accuracy, its stability against volume deformations and its capabilities for accurate reconstruction of anatomical volumes. | ||||
| Address | Sant Petersburg; Russia; July 2013 | ||||
| Corporate Author | Thesis | ||||
| Publisher | Springer Berlin Heidelberg | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | LNCS | ||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0302-9743 | ISBN | 978-3-642-39401-0 | Medium | |
| Area | Expedition | Conference | ICVS | ||
| Notes |
IAM; 600.044; 600.060 | Approved | no | ||
| Call Number | Admin @ si @ GBV2013 | Serial | 2300 | ||
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| Author | Ferran Poveda; Debora Gil; Enric Marti; Albert Andaluz; Manel Ballester;Francesc Carreras Costa | ||||
| Title | Helical structure of the cardiac ventricular anatomy assessed by Diffusion Tensor Magnetic Resonance Imaging multi-resolution tractography | Type | Journal Article | ||
| Year | 2013 | Publication | Revista Española de Cardiología | Abbreviated Journal | REC |
| Volume | 66 | Issue | 10 | Pages | 782-790 |
| Keywords | Heart;Diffusion magnetic resonance imaging;Diffusion tractography;Helical heart;Myocardial ventricular band. | ||||
| Abstract | Deep understanding of myocardial structure linking morphology and function of the heart would unravel crucial knowledge for medical and surgical clinical procedures and studies. Several conceptual models of myocardial fiber organization have been proposed but the lack of an automatic and objective methodology prevented an agreement. We sought to deepen in this knowledge through advanced computer graphic representations of the myocardial fiber architecture by diffusion tensor magnetic resonance imaging (DT-MRI).
We performed automatic tractography reconstruction of unsegmented DT-MRI canine heart datasets coming from the public database of the Johns Hopkins University. Full scale tractographies have been build with 200 seeds and are composed by streamlines computed on the vectorial field of primary eigenvectors given at the diffusion tensor volumes. Also, we introduced a novel multi-scale visualization technique in order to obtain a simplified tractography. This methodology allowed to keep the main geometric features of the fiber tracts, making easier to decipher the main properties of the architectural organization of the heart. On the analysis of the output from our tractographic representations we found exact correlation with low-level details of myocardial architecture, but also with the more abstract conceptualization of a continuous helical ventricular myocardial fiber array. Objective analysis of myocardial architecture by an automated method, including the entire myocardium and using several 3D levels of complexity, reveals a continuous helical myocardial fiber arrangement of both right and left ventricles, supporting the anatomical model of the helical ventricular myocardial band described by Torrent-Guasp. |
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| Publisher | Elsevier | Place of Publication | Editor | ||
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| Notes |
IAM; 600.044; 600.060 | Approved | no | ||
| Call Number | IAM @ iam @ PGM2013 | Serial | 2194 | ||
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| Author | Debora Gil; Antonio Esteban Lansaque; Sebastian Stefaniga; Mihail Gaianu; Carles Sanchez | ||||
| Title | Data Augmentation from Sketch | Type | Conference Article | ||
| Year | 2019 | Publication | International Workshop on Uncertainty for Safe Utilization of Machine Learning in Medical Imaging | Abbreviated Journal | |
| Volume | 11840 | Issue | Pages | 155-162 | |
| Keywords | Data augmentation; cycleGANs; Multi-objective optimization | ||||
| Abstract | State of the art machine learning methods need huge amounts of data with unambiguous annotations for their training. In the context of medical imaging this is, in general, a very difficult task due to limited access to clinical data, the time required for manual annotations and variability across experts. Simulated data could serve for data augmentation provided that its appearance was comparable to the actual appearance of intra-operative acquisitions. Generative Adversarial Networks (GANs) are a powerful tool for artistic style transfer, but lack a criteria for selecting epochs ensuring also preservation of intra-operative content.
We propose a multi-objective optimization strategy for a selection of cycleGAN epochs ensuring a mapping between virtual images and the intra-operative domain preserving anatomical content. Our approach has been applied to simulate intra-operative bronchoscopic videos and chest CT scans from virtual sketches generated using simple graphical primitives. |
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| Address | Shenzhen; China; October 2019 | ||||
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| Series Editor | Series Title | Abbreviated Series Title | LNCS | ||
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| Area | Expedition | Conference | CLIP | ||
| Notes |
IAM; 600.145; 601.337; 600.139; 600.145 | Approved | no | ||
| Call Number | Admin @ si @ GES2019 | Serial | 3359 | ||
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| Author | Albert Andaluz | ||||
| Title | LV Contour Segmentation in TMR images using Semantic Description of Tissue and Prior Knowledge Correction | Type | Report | ||
| Year | 2009 | Publication | CVC Technical Report | Abbreviated Journal | |
| Volume | 142 | Issue | Pages | ||
| Keywords | Active Contour Models; Snakes; Active Shape Models; Deformable Templates; Left Ventricle Segmentation; Generalized Orthogonal Procrustes Analysis; Harmonic Phase Flow; Principal Component Analysis; Tagged Magnetic Resonance | ||||
| Abstract | The Diagnosis of Left Ventricle (LV) pathologies is related to regional wall motion analysis. Health indicator scores such as the rotation and the torsion are useful for the diagnose of the Left Ventricle (LV) function. However, this requires proper identification of LV segments. On one hand, manual segmentation is robust, but it is slow and requires medical expertise. On the other hand, the tag pattern in Tagged Magnetic Resonance (TMR) sequences is a problem for the automatic segmentation of the LV boundaries. Consequently, we propose a method based in the classical formulation of parametric Snakes, combined with Active Shape models. Our semantic definition of the LV is tagged tissue that experiences motion in the systolic cycle. This defines two energy potentials for the Snake convergence. Additionally, the mean shape corrects excessive deviation from the anatomical shape. We have validated our approach in 15 healthy volunteers and two short axis cuts. In this way, we have compared the automatic segmentations to manual shapes outlined by medical experts. Also, we have explored the accuracy of clinical scores computed using automatic contours. The results show minor divergence in the approximation and the manual segmentations as well as robust computation of clinical scores in all cases. From this we conclude that the proposed method is a promising support tool for clinical analysis. | ||||
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| Corporate Author | Thesis | Master's thesis | |||
| Publisher | Place of Publication | Bellaterra 08193, Barcelona, Spain | Editor | ||
| Language | Summary Language | Original Title | |||
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IAM; | Approved | no | ||
| Call Number | IAM @ iam @ And2009 | Serial | 1667 | ||
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| Author | Debora Gil; Jaume Garcia; Mariano Vazquez; Ruth Aris; Guilleaume Houzeaux | ||||
| Title | Patient-Sensitive Anatomic and Functional 3D Model of the Left Ventricle Function | Type | Conference Article | ||
| Year | 2008 | Publication | 8th World Congress on Computational Mechanichs (WCCM8) | Abbreviated Journal | |
| Volume | Issue | Pages | |||
| Keywords | Left Ventricle, Electromechanical Models, Image Processing, Magnetic Resonance. | ||||
| Abstract | Early diagnosis and accurate treatment of Left Ventricle (LV) dysfunction significantly increases the patient survival. Impairment of LV contractility due to cardiovascular diseases is reflected in its motion patterns. Recent advances in medical imaging, such as Magnetic Resonance (MR), have encouraged research on 3D simulation and modelling of the LV dynamics. Most of the existing 3D models [1] consider just the gross anatomy of the LV and restore a truncated ellipse which deforms along the cardiac cycle. The contraction mechanics of any muscle strongly depends on the spatial orientation of its muscular fibers since the motion that the muscle undergoes mainly takes place along the fibers. It follows that such simplified models do not allow evaluation of the heart electro-mechanical function and coupling, which has recently risen as the key point for understanding the LV functionality [2]. In order to thoroughly understand the LV mechanics it is necessary to consider the complete anatomy of the LV given by the orientation of the myocardial fibres in 3D space as described by Torrent Guasp [3].
We propose developing a 3D patient-sensitive model of the LV integrating, for the first time, the ven- tricular band anatomy (fibers orientation), the LV gross anatomy and its functionality. Such model will represent the LV function as a natural consequence of its own ventricular band anatomy. This might be decisive in restoring a proper LV contraction in patients undergoing pace marker treatment. The LV function is defined as soon as the propagation of the contractile electromechanical pulse has been modelled. In our experiments we have used the wave equation for the propagation of the electric pulse. The electromechanical wave moves on the myocardial surface and should have a conductivity tensor oriented along the muscular fibers. Thus, whatever mathematical model for electric pulse propa- gation [4] we consider, the complete anatomy of the LV should be extracted. The LV gross anatomy is obtained by processing multi slice MR images recorded for each patient. Information about the myocardial fibers distribution can only be extracted by Diffusion Tensor Imag- ing (DTI), which can not provide in vivo information for each patient. As a first approach, we have Figure 1: Scheme for the Left Ventricle Patient-Sensitive Model. computed an average model of fibers from several DTI studies of canine hearts. This rough anatomy is the input for our electro-mechanical propagation model simulating LV dynamics. The average fiber orientation is updated until the simulated LV motion agrees with the experimental evidence provided by the LV motion observed in tagged MR (TMR) sequences. Experimental LV motion is recovered by applying image processing, differential geometry and interpolation techniques to 2D TMR slices [5]. The pipeline in figure 1 outlines the interaction between simulations and experimental data leading to our patient-tailored model. |
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| Address | Venice; Italy | ||||
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| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | ISBN | 9788496736559 | Medium | ||
| Area | Expedition | Conference | |||
| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ GGV2008b | Serial | 993 | ||
| Permanent link to this record | |||||
| Author | Jaume Garcia; Debora Gil; Sandra Pujades; Francesc Carreras | ||||
| Title | Valoracion de la Funcion del Ventriculo Izquierdo mediante Modelos Regionales Hiperparametricos | Type | Journal Article | ||
| Year | 2008 | Publication | Revista Española de Cardiologia | Abbreviated Journal | |
| Volume | 61 | Issue | 3 | Pages | 79 |
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| Abstract | La mayoría de la enfermedades cardiovasculares afectan a las propiedades contráctiles de la banda ventricular helicoidal. Esto se refleja en una variación del comportamiento normal de la función ventricular. Parámetros locales tales como los strains, o la deformación experimentada por el tejido, son indicadores capaces de detectar anomalías funcionales en territorios específicos. A menudo, dichos parámetros son considerados de forma separada. En este trabajo presentamos un marco computacional (el Dominio Paramétrico Normalizado, DPN) que permite integrarlos en hiperparámetros funcionales y estudiar sus rangos de normalidad. Dichos rangos permiten valorar de forma objetiva la función regional de cualquier nuevo paciente. Para ello, consideramos secuencias de resonancia magnética etiquetada a nivel basal, medio y apical. Los hiperparámetros se obtienen a partir del movimiento intramural del VI estimado mediante el método Harmonic Phase Flow. El DPN se define a partir de en una parametrización del Ventrículo Izquierdo (VI) en sus coordenadas radiales y circunferencial basada en criterios anatómicos. El paso de los hiperparámetros al DPN hace posible la comparación entre distintos pacientes. Los rangos de normalidad se definen mediante análisis estadístico de valores de voluntarios sanos en 45 regiones del DPN a lo largo de 9 fases sistólicas. Se ha usado un conjunto de 19 (14 H; E: 30.7±7.5) voluntarios sanos para crear los patrones de normalidad y se han validado usando 2 controles sanos y 3 pacientes afectados de contractilidad global reducida. Para los controles los resultados regionales se han ajustado dentro de la normalidad, mientras que para los pacientes se han obtenido valores anormales en las zonas descritas, localizando y cuantificando así el diagnóstico empírico. | ||||
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| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ GRP2008 | Serial | 1032 | ||
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| Author | C. Santa-Marta; Jaume Garcia; A. Bajo; J.J. Vaquero; M. Ledesma-Carbayo; Debora Gil | ||||
| Title | Influence of the Temporal Resolution on the Quantification of Displacement Fields in Cardiac Magnetic Resonance Tagged Images | Type | Conference Article | ||
| Year | 2008 | Publication | XXVI Congreso Anual de la Sociedad Española de Ingenieria Biomedica | Abbreviated Journal | |
| Volume | Issue | Pages | 352–353 | ||
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| Abstract | It is difficult to acquire tagged cardiac MR images with a high temporal and spatial resolution using clinical MR scanners. However, if such images are used for quantifying scores based on motion, it is essential a resolution as high as possibl e. This paper explores the influence of the temporal resolution of a tagged series on the quantification of myocardial dynamic parameters. To such purpose we have designed a SPAMM (Spatial Modulation of Magnetization) sequence allowing acquisition of sequences at simple and double temporal resolution. Sequences are processed to compute myocardial motion by an automatic technique based on the tracking of the harmonic phase of tagged images (the Harmonic Phase Flow, HPF). The results have been compared to manual tracking of myocardial tags. The error in displacement fields for double resolution sequences reduces 17%. | ||||
| Address | Valladolid | ||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | Roberto hornero, Saniel Abasolo | ||
| Language | Summary Language | Original Title | |||
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| Area | Expedition | Conference | CASEIB | ||
| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ SGB2008 | Serial | 1033 | ||
| Permanent link to this record | |||||
| Author | Francesc Carreras; Jaume Garcia; Debora Gil; Sandra Pujadas; Chi ho Lion; R.Suarez-Arias; R.Leta; Xavier Alomar; Manuel Ballester; Guillem Pons-Llados | ||||
| Title | Left ventricular torsion and longitudinal shortening: two fundamental components of myocardial mechanics assessed by tagged cine-MRI in normal subjects | Type | Journal Article | ||
| Year | 2012 | Publication | International Journal of Cardiovascular Imaging | Abbreviated Journal | IJCI |
| Volume | 28 | Issue | 2 | Pages | 273-284 |
| Keywords | Magnetic resonance imaging (MRI); Tagging MRI; Cardiac mechanics; Ventricular torsion | ||||
| Abstract | Cardiac magnetic resonance imaging (Cardiac MRI) has become a gold standard diagnostic technique for the assessment of cardiac mechanics, allowing the non-invasive calculation of left ventric- ular long axis longitudinal shortening (LVLS) and absolute myocardial torsion (AMT) between basal and apical left ventricular slices, a movement directly related to the helicoidal anatomic disposition of the myocardial fibers. The aim of this study is to determine AMT and LVLS behaviour and normal values from a group of healthy subjects. A group of 21 healthy volunteers (15 males) (age: 23–55 y.o., mean:30.7 ± 7.5) were prospectively included in an obser- vational study by Cardiac MRI. Left ventricular rotation (degrees) was calculated by custom-made software (Harmonic Phase Flow) in consecutive LV short axis planes tagged cine-MRI sequences. AMT was determined from the difference between basal and apical planes LV rotations. LVLS (%) was determined from the LV longitudinal and horizontal axis cine-MRI images. All the 21 cases studied were interpretable, although in three cases the value of the LV apical rotation could not be determined. The mean rotation of the basal and apical planes at end-systole were -3.71° ± 0.84° and 6.73° ± 1.69° (n:18) respectively, resulting in a LV mean AMT of 10.48° ± 1.63° (n:18). End-systolic mean LVLS was 19.07 ± 2.71%. Cardiac MRI allows for the calculation of AMT and LVLS, fundamental functional components of the ventricular twist mechanics conditioned, in turn, by the anatomical helical layout of the myocardial fibers. These values provide complementary information about systolic ventricular function in relation to the traditional parameters used in daily practice. | ||||
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| Publisher | Springer Netherlands | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1569-5794 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ CGG2012 | Serial | 1496 | ||
| Permanent link to this record | |||||
| Author | Jaume Garcia; Debora Gil; Francesc Carreras; Sandra Pujades; R.Leta; Xavier Alomar; Guillem Pons-LLados | ||||
| Title | Patrons de Normalitat Regional per la Valoració de la Funció del Ventricle Esquerre | Type | Conference Article | ||
| Year | 2008 | Publication | XX Congrés de la Societat Catalana de Cardiologia | Abbreviated Journal | |
| Volume | Issue | Pages | 60 | ||
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| Abstract | Les malalties cardiovasculars afecten les propietats contràctils de la banda ventricular i provoquen una variació de la funció del Ventricle Esquerre (VE) . Només els indicadors locals (strains, la deformació del teixit) són capaços de detectar anomalies en territoris específics del VE . Patrons de normalitat regionals d’aquests paràmetres serien d’utilitat a l’hora de valorar-ne la funció .
Presentem un Domini Paramètric Normalitzat (DPN) que permet comparar dades de diferents pacients i definir Patrons de Normalitat Regional (PNR) |
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| Publisher | Place of Publication | Barcelona | Editor | ||
| Language | catalan | Summary Language | catalan | Original Title | |
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| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ GGC2008b | Serial | 1503 | ||
| Permanent link to this record | |||||
| Author | Jaume Garcia | ||||
| Title | Generalized Active Shape Models Applied to Cardiac Function Analysis | Type | Report | ||
| Year | 2004 | Publication | CVC Technical Report | Abbreviated Journal | |
| Volume | Issue | 78 | Pages | ||
| Keywords | Cardiac Analysis; Deformable Models; Active Contour Models; Active Shape Models; Tagged MRI; HARP; Contrast Echocardiography. | ||||
| Abstract | Medical imaging is very useful in the assessment and treatment of many diseases. To deal with the great amount of data provided by imaging scanners and extract quantitative information that physicians can interpret, many analysis algorithms have been developed. Any process of analysis always consists of a first step of segmenting some particular structure. In medical imaging, structures are not always well defined and suffer from noise artifacts thus, ordinary segmentation methods are not well suited. The ones that seem to give better results are those based on deformable models. Nevertheless, despite their capability of mixing image features together with smoothness constraints that may compensate for image irregularities, these are naturally local methods, i. e., each node of the active contour evolve taking into account information about its neighbors and some other weak constraints about flexibility and smoothness, but not about the global shape that they should find. Due to the fact that structures to be segmented are the same for all cases but with some inter and intra-patient variation, the incorporation of a priori knowledge about shape in the segmentation method will provide robustness to it. Active Shape Models is an algorithm based on the creation of a shape model called Point Distribution Model. It performs a segmentation using only shapes similar than those previously learned from a training set that capture most of the variation presented by the structure. This algorithm works by updating shape nodes along a normal segment which often can be too restrictive. For this reason we propose a generalization of this algorithm that we call Generalized Active Shape Models and fully integrates the a priori knowledge given by the Point Distribution Model with deformable models or any other appropriate segmentation method. Two different applications to cardiac imaging of this generalized method are developed and promising results are shown. | ||||
| Address | CVC (UAB) | ||||
| Corporate Author | Thesis | Master's thesis | |||
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| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ Gar2004 | Serial | 1513 | ||
| Permanent link to this record | |||||
| Author | Debora Gil | ||||
| Title | Geometric Differential Operators for Shape Modelling | Type | Book Whole | ||
| Year | 2004 | Publication | PhD Thesis, Universitat Autonoma de Barcelona-CVC | Abbreviated Journal | |
| Volume | Issue | Pages | |||
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| Abstract | Medical imaging feeds research in many computer vision and image processing fields: image filtering, segmentation, shape recovery, registration, retrieval and pattern matching. Because of their low contrast changes and large variety of artifacts and noise, medical imaging processing techniques relying on an analysis of the geometry of image level sets rather than on intensity values result in more robust treatment. From the starting point of treatment of intravascular images, this PhD thesis ad- dresses the design of differential image operators based on geometric principles for a robust shape modelling and restoration. Among all fields applying shape recovery, we approach filtering and segmentation of image objects. For a successful use in real images, the segmentation process should go through three stages: noise removing, shape modelling and shape recovery. This PhD addresses all three topics, but for the sake of algorithms as automated as possible, techniques for image processing will be designed to satisfy three main principles: a) convergence of the iterative schemes to non-trivial states avoiding image degeneration to a constant image and representing smooth models of the originals; b) smooth asymptotic behav- ior ensuring stabilization of the iterative process; c) fixed parameter values ensuring equal (domain free) performance of the algorithms whatever initial images/shapes. Our geometric approach to the generic equations that model the different processes approached enables defining techniques satisfying all the former requirements. First, we introduce a new curvature-based geometric flow for image filtering achieving a good compromise between noise removing and resemblance to original images. Sec- ond, we describe a new family of diffusion operators that restrict their scope to image level curves and serve to restore smooth closed models from unconnected sets of points. Finally, we design a regularization of snake (distance) maps that ensures its smooth convergence towards any closed shape. Experiments show that performance of the techniques proposed overpasses that of state-of-the-art algorithms. | ||||
| Address | |||||
| Corporate Author | Thesis | Ph.D. thesis | |||
| Publisher | Ediciones Graficas Rey | Place of Publication | Barcelona (Spain) | Editor | Jordi Saludes i Closa;Petia Radeva |
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| ISSN | ISBN | 84-933652-0-3 | Medium | prit | |
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| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ GIL2004 | Serial | 1517 | ||
| Permanent link to this record | |||||
| Author | Debora Gil | ||||
| Title | Regularized Curvature Flow | Type | Report | ||
| Year | 2002 | Publication | CVC Technical Report | Abbreviated Journal | |
| Volume | Issue | 63 | Pages | ||
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| Publisher | Computer Vision Centre | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
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IAM; | Approved | no | ||
| Call Number | IAM @ iam @ Gil2002 | Serial | 1518 | ||
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| Author | Debora Gil; Jose Maria-Carazo; Roberto Marabini | ||||
| Title | On the nature of 2D crystal unbending | Type | Journal Article | ||
| Year | 2006 | Publication | Journal of Structural Biology | Abbreviated Journal | |
| Volume | 156 | Issue | 3 | Pages | 546-555 |
| Keywords | Electron microscopy | ||||
| Abstract | Crystal unbending, the process that aims to recover a perfect crystal from experimental data, is one of the more important steps in electron crystallography image processing. The unbending process involves three steps: estimation of the unit cell displacements from their ideal positions, extension of the deformation field to the whole image and transformation of the image in order to recover an ideal crystal. In this work, we present a systematic analysis of the second step oriented to address two issues. First, whether the unit cells remain undistorted and only the distance between them should be changed (rigid case) or should be modified with the same deformation suffered by the whole crystal (elastic case). Second, the performance of different extension algorithms (interpolation versus approximation) is explored. Our experiments show that there is no difference between elastic and rigid cases or among the extension algorithms. This implies that the deformation fields are constant over large areas. Furthermore, our results indicate that the main source of error is the transformation of the crystal image. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1047-8477 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes |
IAM; | Approved | no | ||
| Call Number | IAM @ iam @ GCM2006 | Serial | 1519 | ||
| Permanent link to this record | |||||