Comparison of Local and Global Region Merging in the Topological Map

International audienceThe topological map is a model that represents 2D and 3D images subdivision. It aims to allow the use of topological and geometrical features of the subdivision in image processing operations. When handling regions in an image, one of the main operation is the region merging, for example in segmentation process. This paper presents two algorithms of region merging in 3D topological maps: one local which modifies locally the map around merged regions, and another one global which runs through all the elements of the map. We study their complexities and present experimental results to compare both approaches

First Results for 3D Image Segmentation with Topological Map

International audienceThis paper presents the first segmentation operation defined within the 3D topological map framework. Firstly we show how a traditional segmentation algorithm, found in the literature, can be transposed on a 3D image represented by a topological map. We show the consistency of the results despite of the modifications made to the segmentation algorithm and we study the complexity of the operation. Lastly, we present some experimental results made on 3D medical images. These results show the process duration of this method and validate the interest to use 3D topological map in the context of image processing

Fully Deformable 3D Digital Partition Model with Topological Control

International audienceWe propose a purely discrete deformable partition model for segmenting 3D images. Its main ability is to maintain the topology of the partition during the minimization process. To do so, our main contribution is a new definition of multi-label simple points (ML simple point) that is easily computable. An ML simple point can be relabeled without modifying the overall topology of the partition. The definition is based on intervoxel properties, and uses the notion of collapse on cubical complexes. This work is an extension of a former restricted definition [DupasAl09] that prohibits the move of intersections of boundary surfaces. A deformation process is carried out with a greedy energy minimization algorithm. A discrete area estimator is used to approach at best standard regularizers classically used in continuous energy minimizing methods. We illustrate the potential of our approach with the segmentation of 3D medical images with known expected topology

Combining Topological Maps, Multi-Label Simple Points, and Minimum-Length Polygons for Efficient Digital Partition Model

International audienceDeformable models have shown great potential for image segmentation. They include discrete models whose combinatorial formulation leads to efficient and sometimes optimal minimization algorithms. In this paper, we propose a new discrete framework to deform any partition while preserving its topology. We show how to combine the use of multi-label simple points, topological maps and minimum-length polygons in order to implement an efficient digital deformable partition model. Our experimental results illustrate the potential of our framework for segmenting images, since it allows the mixing of region-based, contour-based and regularization energies, while keeping the overall image structure

Zika: abordagem clínica na atenção básica

Zika é uma doença que foi detectada no país no último ano, a partir deste evento a doença tem se disseminado no país, cursando de forma inédita segundo a literatura científica. Tendo encontrado ambiente favorável à sua disseminação, que é a presença do vetor Aedes em todo o país, em população sem imunidade à doença, vem causando enorme impacto à saúde de nossa população. É preciso que os profissionais de saúde se capacitem para conseguir minimizar o impacto desta enfermidade, utilizando todos os recursos possíveis para assistir, disseminar os conhecimentos para a população, além de construir parcerias com todos os equipamentos sociais para atuarem no sentido de proteger a saúde de todos. Para isso este material foi elaborado, tendo o caráter auto-instrucional, os profissionais de saúde podem realizá-lo dentro de suas possibilidades. O módulo tem 45h, sendo dividido em quatro unidades de ensino; ao final oferece uma avaliação objetiva e a certificação on-line. Na biblioteca estão disponibilizados livros e vídeos com conteúdos referentes ao tema, utilize-os se sentir necessidade de aprofundar seus conhecimentos.1.

1-Azabicyclic compounds ring-opening : synthesis of azepanes and azetidines

Les hétérocycles azotés sont rencontrés dans de très nombreux produits naturels et/ou biologiquement actifs. Le développement de méthodes de synthèse sélectives d’hétérocycles azotés constitue donc un défi important pour la découverte de nouvelles molécules actives en chimie médicinale ou en agrochimie. Dans ce contexte, nos travaux ont porté sur la mise au point de réactions d’ouverture régiosélectives de composés 1-azabicycliques, diversement substitués, par des nucléophiles pour accéder à des azépanes et à des azétidines. Des 1 azabicyclo[4.1.0]heptanes ont été préparés à partir d’azirines, par une séquence impliquant une allylation diastéréosélective et une métathèse cyclisante pour construire le cycle à six chaînons, puis la transformation de la double liaison carbone-carbone endocyclique grâce à des réactions d’hydrogénation, d’addition-1,4 ou de cycloaddition 1,3-dipolaire. Différentes conditions ont été développées pour réaliser ensuite l’ouverture régiosélective des 1 azabicyclo[4.1.0]heptan-2-ones ainsi obtenues par des acides carboxyliques, des thiols ou des thioacides, ce qui a permis d’accéder à des azépanones diversement substituées, possédant une fonction ester ou un groupe trifluorométhyle en alpha de l’atome d’azote. La cyclopropanation diastéréosélective de 2-(trifluorométhyl)azirines a été utilisée pour construire de nouveaux 1 azabicyclo[1.1.0]butanes dont l’ouverture régiosélective par des chloroformiates et par l’anhydride trifloroacétique a ensuite conduit respectivement à des 3 chloroazétidines ou des azétidin-3 ols trifluorométhylés possédant deux centres stéréogènes adjacents contrôlés.Nitrogen heterocycles are encountered in numerous natural products and/or bioactive compounds. The development of selective synthetic methods toward nitrogen heterocycles is of prime importance for the discovery of new bioactive compounds in medicinal chemistry of agrochemistry. In this context, our research work has been devoted to the design of regioselective ring-opening reactions of diversely substituted 1-azabicyclic compounds, with the goal of accessing azepanes and azetidines. Several 1-azabicyclo[4.1.0]heptanes were prepared from azirines, through a sequence involving a diastereoslective allylation and a ring-clsoing metathesis reaction to construct the six-membered ring, followed by transformation of the endocyclic olefin using either a hydrogenation, a 1,4-addition or a 1,3-dipolar cycloaddition. Then, different conditions were developed to achieve the ring-opening of the resulting 1 azabicyclo[4.1.0]heptan-2-ones, using carboxylic acids, thiols and thioacids as nucleophiles, which eventually delivered diversely substituted azepanones possessing an ester moiety or a trifluoromethyl group at the alpha position of the nitrogen atom. The diastereoselective cyclopropanation of 2 (trifluoromethyl)azirines was used to elaborate new substituted 1 azabicyclo[1.1.0]butanes, which then underwent regioselective ring-opening with chloroformates and trifluoroacetic anhydride to provide trifluoromethylated 3 chloroazetidines or azetidin-3 ols incorporating two adjacent stereocenters

Opérations et Algorithmes pour la Segmentation Topologique d'Images 3D

A 3D topological map is a model used in image processing which represents the partition of a 3D image into regions. In this work, we introduce some tools that allow to modify a partition presented by a topological map, and we use these tools to propose segmentation algorithms implementing topological criteria. In a first part, we propose three operations. The region merging is defined with a local approach suited for interactive use, and a global approach suited for automatic processing like image segmentation. The region splitting is introduced with a burst into voxel approach, and the split with a guide. Last, a deformation of the partition based on the definition of ML-Simple points: voxels that can be flipped of region without changing the topology of the partition. With these operations, we implement in a second part image segmentation processes using topological maps. First we adapt to our model an existing algorithm using a criterion based on the notion of contrast. Then, we propose methods to compute topological invariants of regions: the Betti numbers. Using these methods we implement a topological criterion that controls the number of tunnels and cavities of the regions. Last, we give an overview of the possibilities of our tools by creating a toolchain to segment brain tumors in medical images.Une carte topologique 3D est un modèle servant à représenter la partition en régions d'une image 3D pour le traitement d'images. Dans ce travail, nous développons des outils permettant de modifier la partition représentée par une carte topologique, puis nous utilisons ces outils afin de proposer des algorithmes de segmentation intégrant des critères topologiques. Dans une première partie, nous proposons trois opérations. La fusion de régions est définie avec une approche locale adaptée à une utilisation interactive et une approche globale pour une utilisation automatisée comme lors d'une segmentation. La division de régions est proposée avec une méthode d'éclatement en voxels et la division à l'aide d'un guide. Enfin, la déformation de la partition est basée sur la définition de points ML-Simples : des voxels pouvant changer de région sans modifier la topologie de la partition. À l'aide de ces opérations, nous mettons en œuvre dans une seconde partie des algorithmes de segmentation d'images utilisant les cartes topologiques. Notre première approche adapte au modèle des cartes topologiques un algorithme existant qui utilise un critère basé sur la notion de contraste. Nous proposons ensuite des méthodes de calcul d'invariants topologiques sur les régions : les nombres de Betti. Grâce à eux, nous développons un critère topologique de segmentation permettant de contrôler le nombre de tunnels et de cavités des régions. Enfin, nous illustrons les possibilités de tous nos outils en mettant en place une chaîne de traitement pour la segmentation de tumeurs cérébrales dans des images médicales

Multi-Label Simple Points Definition for 3D Images Digital Deformable Model

International audienceThe main contribution of this paper is the definition of multi-label simple points that ensures that the partition topology remains invariant during a deformable partition process. The definition is based on simple intervoxel properties and is easy to implement. A deformation process is carried out with a greedy energy minimization algorithm. A discrete area estimator is used to approach at best standard regularizers classically used in continuous energy minimizing methods. The effectiveness of our approach is shown on several 3D image segmentations

Combinatorial Maps for 2D and 3D Image Segmentation

International audienceThis chapter shows how combinatorial maps can be used for 2D or 3D image segmentation. We start by introducing combinatorial maps and we show how they can be used to describe image partitions. Then, we present a generic segmentation algorithm that uses and modifies the image partition represented by a combinatorial map. One advantage of this algorithm is that one can mix different criteria and use different image features which can be associated with the cells of the partition. In particular, it is interesting that the topological properties of the image partition can be controlled through this approach. This property is illustrated by the computation of classical topological invariants, known as Betti numbers, which are then used to control the number of cavities or the number of tunnels of regions in the image partition. Finally, we present some experimental results of 2D and 3D image segmentation using different criteria detailed in this chapter