Contribution à la classification d'images satellitaires par approche variationnelle et équations aux dérivées partielles.

Abstract : This work is devoted to the development and the implementation of variational models for image classification. Image classification, which consists in assiging a label to each pixel of a given image, concerns many applications since it is often the basic processing for many image interpretation systems. Many models have been developed within a stochastic framework or using structural approaches, but rarely within a variational framework whose efficiency has largely been proved for a wide variety of problems such as image reconstruction or restoration. The first model we propose herein is based on the minimization of a criterion family whose set of solutions in converging to a partition of the data set composed of homogeneous regions with regularized boundaries. This approach takes place within the context of free boundary problems and we use the ì-convergence theory for the theoretical study. The set of functionals we minimize contains a regularization term and a classification one. As the set of functionals is converging, the behavior of the model is progressively changing: the restoration process is vanishing while the labeling one is rising. The second model we propose is based on a set of active regions and contours. We use a level set formulation to define the criterion we want to minimize, this formulation allows a change of topology of the evolving sets. Each class and its associated set of regions and boundaries is defined thanks to a level set function. From the Euler equations, we solve a system of coupled partial differential equations through a dynamical scheme. The evolution of each region is governed by forces constraining the partition to be composed of homogeneous classes with smooth boundaries. We have conducted many experiments on both synthetic and real images. We have extended these models to the multispectral case for which the data are a set of images, and we show some results and comparisons on SPOT XS images.
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Modeling and Simulation. Université Nice Sophia Antipolis, 2000. French


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Submitted on : Tuesday, September 9, 2008 - 10:53:03 AM
Last modification on : Tuesday, September 9, 2008 - 10:58:31 AM

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Christophe Samson. Contribution à la classification d'images satellitaires par approche variationnelle et équations aux dérivées partielles.. Modeling and Simulation. Université Nice Sophia Antipolis, 2000. French. <tel-00319709>

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