Compactly supported radial basis functions: multidimensional reconstruction and applications

Cette thèse traite l\u27application des fonctions de base radiale, à support compact (CSRBF), pour la reconstruction multidimensionnelle de signaux et de surfaces à partir d\u27échantillons, ainsi que pour la segmentation des images. En particulier, cette approche permet de considérer l\u27échantillonnage irrégulier. Dans chacune de ces applications nous proposons de nouvelles méthodes. Pour la reconstruction multidimensionnelle de signaux nous proposons une approximation multirésolution basée sur une classification hiérarchique des échantillons, puis une approximation adaptative avec calcul local du support de chaque CSRBF. Pour la reconstruction de surfaces implicites, nous proposons une méthode composite qui associe la partition de l\u27unité et les CSRBF, puis une approximation adaptative où le support de chaque CSRBF est déterminé à partir d\u27une approximation de l\u27axe médian. Enfin, nous proposons un formalisme de collocation pour la résolution de l\u27équation de propagation des ensembles de niveaux en segmentation, par représentation de la fonction implicite sur une base de fonctions. En particulier, nous illustrons cette méthode avec les CSRBF en segmentation d\u27images médicales

Compactly supported radial basis functions (multidimensional reconstruction and applications)

Cette thèse traite l application des fonctions de base radiale, à support compact (CSRBF), pour la reconstruction multidimensionnelle de signaux et de surfaces à partir d échantillons, ainsi que pour la segmentation des images. En particulier, cette approche permet de considérer l échantillonnage irrégulier. Dans chacune de ces applications nous proposons de nouvelles méthodes. Pour la reconstruction multidimensionnelle de signaux nous proposons une approximation multirésolution basée sur une classification hiérarchique des échantillons, puis une approximation adaptative avec calcul local du support de chaque CSRBF. Pour la reconstruction de surfaces implicites, nous proposons une méthode composite qui associe la partition de l unité et les CSRBF, puis une approximation adaptative où le support de chaque CSRBF est déterminé à partir d une approximation de l axe médian. Enfin, nous proposons un formalisme de collocation pour la résolution de l équation de propagation des ensembles de niveaux en segmentation, par représentation de la fonction implicite sur une base de fonctions. En particulier, nous illustrons cette méthode avec les CSRBF en segmentation d images médicales.This thesis deals with the application of Compactly Supported Radial Basis Functions (CSRBFs) for reconstruction and image segmentation. Reconstruction consists in finding a (continuous) function which fits good to some given samples. Image segmentation consists in finding limits of relevant areas in images. These general problems are essential for the study, analysis, further processing of data, such as multidimensional signals, images, or surfaces. In each listed application, we propose new methods. For multidimensional signal reconstruction from non-uniform samples, we propose a new multiresolution scheme based on a hierarchical data clustering and an adaptive approximation method, where the support of each CSRBF is calculated locally. For implicit surface based reconstruction, we propose a composite approach which solves locally the reconstruction problem and blends all solutions together by partition of unity, and an adaptive approximation method, where the support of each CSRBF is locally computed from an approximation of the Medial axis. Finally, we propose a new collocation formalism for solving the level set propagation equations in image segmentation, by expanding the evolving implicit function on a basis functions. In particular, we illustrate this method with CSRBFs in medical image segmentation.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Variational implicit surface meshing

Proceedings of IEEE International Conference on Shape Modeling and Applications SMI 2009International audienceIn this paper, we propose a new algorithm to mesh implicit surfaces which produces meshes both with a good triangle aspect ratio as well as a good approximation quality. The number of vertices of the output mesh is defined by the end-user. For this goal, we perform a two-stage processing : an initialization step followed by an iterative optimization step. The initialization step consists in capturing the surface topology and allocating the vertex budget. The optimization algorithm is based on a variational vertices relaxation and triangulation update. In addition a gradation parameter can be defined to adapt the mesh sampling to the curvature of the implicit surface. We demonstrate the efficiency of the approach on synthetic models as well as real-world acquired data, and provide comparisons with previous approaches

Utilisation et acceptabilité des moustiquaires imprégnées au niveau familial en milieu rural - Mbébé-Kikot-Cameroun

En Afrique sub-saharienne, le paludisme demeure un des probRmcs essentiels de Santé Publique. Y faire face passe actuellement par une chimio thérapie adaptée des acch fébriles (OMS-1986) et par IC renforcemen

Specified neural progenitors sort to form sharp domains after noisy Shh signaling

Sharply delineated domains of cell types arise in developing tissues under instruction of inductive signal (morphogen) gradients, which specify distinct cell fates at different signal levels. The translation of a morphogen gradient into discrete spatial domains relies on precise signal responses at stable cell positions. However, cells in developing tissues undergoing morphogenesis and proliferation often experience complex movements, which may affect their morphogen exposure, specification, and positioning. How is a clear pattern achieved with cells moving around? Using in toto imaging of the zebrafish neural tube, we analyzed specification patterns and movement trajectories of neural progenitors. We found that specified progenitors of different fates are spatially mixed following heterogeneous Sonic Hedgehog signaling responses. Cell sorting then rearranges them into sharply bordered domains. Ectopically induced motor neuron progenitors also robustly sort to correct locations. Our results reveal that cell sorting acts to correct imprecision of spatial patterning by noisy inductive signals

SimpleElastix: v0.9.0

Add SimpleITK support for elastix and transformix Add SimpleITK support for 4D image

Outcome of long gap esophageal atresia at 6 years: A prospective case control cohort study

International audienceBackground data: EA is the most frequent congenital esophageal malformation. Long gap EA remains a therapeutic challenge for pediatric surgeons. A case case-control prospective study from a multi-institutional national French data base was performed to assess the outcome, at age of 1 and 6 years, of long gap esophageal atresia (EA) compared with non-long gap EA/tracheo-esophageal fistula (TEF). The secondary aim was to assess whether initial treatment (delayed primary anastomosis of native esophagus vs. esophageal replacement) influenced mortality and morbidity at ages 1 and 6 years.Methods: A multicentric population-based prospective study was performed and included all patients who underwent EA surgery in France from January 1, 2008 to December 31, 2010. A comparative study was performed with non-long gap EA/TEF patients. Morbidity at birth, 1 year, and 6 years was assessed.Results: Thirty-one patients with long gap EA were compared with 62 non-long gap EA/TEF patients. At age 1 year, the long gap EA group had longer parenteral nutrition support and longer hospital stay and were significantly more likely to have complications both early post-operatively and before age 1 year compared with the non-long gap EA/TEF group. At 6 years, digestive complications were more frequent in long gap compared to non-long gap EA/TEF patients. Tracheomalacia was the only respiratory complication that differed between the groups. Spine deformation was less frequent in the long gap group. There were no differences between conservative and replacement groups at ages 1 and 6 years except feeding difficulties that were more common in the native esophagus group.Conclusions: Long gap strongly influenced digestive morbidity at age 6 years.Keywords: Complications; Dysphagia; Esophageal atresia; Esophageal replacement; Gastro-esophageal reflux disease; Long gap esophageal atresia; Midterm outcomes

Feeding disorders in children with oesophageal atresia: a cross-sectional study

International audienceIntroduction With advances in surgical and neonatal care, the survival of patients with oesophageal atresia (OA) has improved over time. Whereas a number of OA-related conditions (delayed primary anastomosis, anastomotic stricture and oesophageal dysmotility) may have an impact on feeding development and although children with OA experience several oral aversive events, paediatric feeding disorders (PFD) remain poorly described in this population. The primary aim of our study was to describe PFD in children born with OA, using a standardised scale. The secondary aim was to determine conditions associated with PFD. Methods The Feeding Disorders in Children with Oesophageal Atresia Study is a national cohort study based on the OA registry from the French National Network. Parents of children born with OA between 2013 and 2016 in one of the 22 participating centres were asked to complete the French version of the Montreal Children’s Hospital Feeding Scale. Results Of the 248 eligible children, 145 children, with a median age of 2.3 years (Q1–Q3 1.8–2.9, min–max 1.1–4.0 years), were included. Sixty-one children (42%) developed PFD; 13% were tube-fed (n=19). Almost 40% of children with PFD failed to thrive (n=23). The presence of chronic respiratory symptoms was associated with the development of PFD. Ten children with PFD (16%) had no other condition or OA-related complication. Conclusion PFD are common in children with OA, and there is no typical profile of patients at risk of PFD. Therefore, all children with OA require a systematic screening for PFD that could improve the care and outcomes of patients, especially in terms of growth