Jean-Michel Létang

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In this paper, we propose to take advantage of computer graphics hardware to achieve an accelerated simulation of X-ray transmission imaging, and we compare results with a fast and robust software-only implementation. The running times of the GPU and CPU implementations are compared in different test cases. The results show that the GPU implementation with(More)
This paper deals with the detection of moving objects. We have deened a method able to cope with perturbations frequently encountered during acquisition of outdoor image sequences: camera not perfectly stationary, illumination modiications, occlusions, ... Temporal integration and statistical regularization are the two main features of the method. A(More)
The core contribution of this study is a mathematical model of combination of stereopsis and kineopsis under active viewing, a model to serve as a basis for algorithms implemental of active stereokinematic analysis of visual data. The model is specified by two main groups of equations: (A) The fundamental equations of interpretation: they relate the(More)
In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy,(More)
The use of protons in radiotherapy offers a very precise and effective tool for malignant tumor treatment. In order to fully exploit the benefits of proton therapy, a precise determination of the proton range inside the patient is needed. Currently, this information is provided by conventional X-ray CT. In our work, we explore the theoretical limits of(More)
Accurate quantitative reconstruction in kV cone-beam computed tomography (CBCT) is challenged by the presence of secondary radiations (scattering, fluorescence, and bremsstrahlung photons) coming from the object and from the detector itself. The authors present a simulation study of the CBCT imaging chain and its integration into a comprehensive correction(More)
In this paper, we propose a deterministic simulation of X-ray transmission imaging on graphics hardware. Only the directly transmitted photons are simulated, using the Beer-Lambert law. Our previous attempt to simulate X-ray attenuation from polygon meshes utilising the GPU showed significant increase of performance, with respect to a validated software(More)
Accurate Monte Carlo simulations are essential both for the development of an optimized detection array that will be used in clinical practice for precise ion beam range monitoring. Within GEANT4, both the Quantum Molecular Dynamics (QMD) and the Binary Cascade (BIC) models overestimate the overall prompt-gamma depth profile yields measured with carbon ion(More)
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