Clothilde Mélot

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Cone-Beam Computerized Tomography (CBCT) and Positron Emission Tomography (PET) are two complementary medical imaging modalities providing respectively anatomic and metabolic information of a patient. In the context of public health, one must address the problem of dose reduction of the potentially harmful quantities related to each exam protocol : X-rays(More)
Cone Beam Computerized Tomography (CBCT) and Positron Emission Tomography (PET) Scans are medical imaging devices that require solving ill-posed inverse problems. The models considered come directly from the physics of the acquisition devices, and take into account the specificity of the (Poisson) noise. We propose various fast numerical schemes to compute(More)
Let (Xt, t ≥ 0) be an α-stable random walk with values in Z. Let lt(x) = ∫ t 0 δx(Xs)ds be its local time. For p > 1, not necessarily integer, It = ∑ x l p t (x) is the so-called p-fold selfintersection local time of the random walk. When p(d − α) < d, we derive precise logarithmic asymptotics of the probability P [It ≥ rt] for all scales rt E [It]. Our(More)
We propose a new method for performing multiscale analysis of functions defined on the vertices of a finite connected weighted graph. Our approach relies on a random spanning forest to downsample the set of vertices, and on approximate solutions of Markov intertwining relation to provide a subgraph structure and a filter bank leading to a wavelet basis of(More)
Our goal is to study the multifractal properties of functions of a given family which have few non vanishing wavelet coefficients. We compute at each point the pointwise Hölder exponent of these functions and also their local L regularity, computing the so-called p-exponent. We prove that in the general case the Hölder and p exponent are different at each(More)
Bijan Afsari Young Joon Ahn Andrés Almansa Andreas Alpers L. Alvarez Eric Andres Michel Antunes Erchan Aptoula Pablo Arias Ery Arias-Castro Jean-Francois Aujol George Azzopardi Martin Bähr Lu Bai Peter Balazs Coloma Ballester Joao Barreto Thomas Batard Joost Batenburg Étienne Baudrier Amir Beck Alexander Beigl Martin Benning Ronny Bergmann Bejamin Berkels(More)
Multifractal analysis has become a standard signal processing tool, for which a promising new formulation, the <inline-formula><tex-math notation="LaTeX">$\boldsymbol {p}$</tex-math></inline-formula>-leader multifractal formalism, has recently been proposed. It relies on novel multiscale quantities, the <inline-formula><tex-math notation="LaTeX">(More)
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