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5 results on '"Caifang Cai"'

1. Reconstruction de fissures 2D à partir d’images courants de Foucault utilisant un modèle direct semi-analytique

Author

Thierry Bore, Eric Vourc'H, Romain Soulat, Caifang Cai, Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École normale supérieure - Rennes (ENS Rennes)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Spécification et Vérification [Cachan] (LSV), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
Surface (mathematics), Synthetic data, [SPI.TRON]Engineering Sciences [physics]/Electronics, Image (mathematics), law.invention, law, Genetic algorithm, Eddy current, Current (fluid), Engineering (miscellaneous), Instrumentation, Algorithm, ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, Excitation, Geology
Abstract

We propose a method for reconstructing 2D surface cracks in electrically conducting parts from Eddy-current images. The proposed method relies on the use of a direct semi-analytic model suitable for Eddy-current systems featuring a uniform current excitation. The surface crack reconstruction approach is based on the comparison of eddy current images computed by the model with the eddy current image of the crack to reconstruct. The method is implemented by means of a genetic algorithm and accurate reconstruction is carried out with synthetic data.

Published
2016
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2. 3D reconstruction of surface cracks using bi-frequency eddy current images and a direct semi-analytic model

Author

Eric Vourc'H, Nicolas Gasnier, Caifang Cai, Florentin Delaine, Thierry Bore, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), University of Queensland [Brisbane], Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École normale supérieure - Rennes (ENS Rennes)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Surface (mathematics), History, Computer science, Computation, 020208 electrical & electronic engineering, Analytic model, 3D reconstruction, 02 engineering and technology, Inverse problem, 01 natural sciences, Reconstruction method, Computer Science Applications, Education, law.invention, [SPI.TRON]Engineering Sciences [physics]/Electronics, law, 0103 physical sciences, Genetic algorithm, 0202 electrical engineering, electronic engineering, information engineering, Eddy current, 010301 acoustics, Algorithm, ComputingMilieux_MISCELLANEOUS
Abstract

We propose a method for reconstructing 3D surface cracks in metallic parts form eddy current (EC) images. To do so, we use a semi-analytic direct model for representing the interactions between EC and a crack. In order to cope with the inverse problem cons isting in reconstructing 3D cracks, we propose the use of a genetic algorithm based on the computation of bi-frequency EC images. Numerical experiments are carried out in order to analyze the performance of the reconstruction method for different signal to noise ratios. Moreover, the results a bi-frequency genetic algorithm are compared to those a mono-frequency algorithm.

Published
2017
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3. 3D reconstruction of surface cracks using bi-frequency eddy current images and a direct semi-analytic model

Author

Caifang Cai, Thierry Bore, Florentin Delaine, Nicolas Gasnier, Romain Soulat, Eric Vourc'H, Vourc'H, Eric, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), University of Queensland [Brisbane], Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École normale supérieure - Rennes (ENS Rennes)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Spécification et Vérification [Cachan] (LSV), and École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, ComputingMilieux_MISCELLANEOUS, [SPI.TRON] Engineering Sciences [physics]/Electronics, [SPI.TRON]Engineering Sciences [physics]/Electronics, [SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience

Published
2017

4. Surface crack reconstruction from eddy current images using a direct semi-analytic model

Author

Romain Soulat, Eric Vourc'H, Caifang Cai, Thierry Bore, Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE), École normale supérieure - Rennes (ENS Rennes)-Université Paris-Sud - Paris 11 (UP11)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Université Gustave Eiffel (UNIV GUSTAVE EIFFEL), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Spécification et Vérification [Cachan] (LSV), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École normale supérieure - Rennes (ENS Rennes)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des signaux et systèmes (L2S), and Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Surface (mathematics), History, Engineering, Flow (psychology), [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], eddy current, Education, law.invention, law, Nondestructive testing, Genetic algorithm, Convergence (routing), Electronic engineering, Eddy current, genetic algorithm, Sensitivity (control systems), ComputingMilieux_MISCELLANEOUS, nondestructive testing, business.industry, imaging, crack retrieval, Computer Science Applications, [SPI.TRON]Engineering Sciences [physics]/Electronics, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, business, Algorithm, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Excitation
Abstract

International audience; A method relying on a direct semi-analytic model is proposed for reconstructing cracks from eddy current images. We consider systems featuring a uniform excitation flow which can be modelled by means of fictitious current sources distributed in the crack volume. Thanks to the relative simplicity of the model a reconstruction method based the comparison of EC images is considered. The sensitivity of different images comparison criteria is studied for 2D surface cracks, leading to a reconstruction method based on a genetic algorithm. Numerical experiments are carried out to examine the performances of the algorithm in terms of convergence and accuracy.

Published
2015
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5. Bayesian data fusion and inversion in X-ray multi-energy computed tomography

Author

Thomas Rodet, Caifang Cai, All Mohammad-Djafari, Samuel Legoupil, Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
Bayes estimator, Image fusion, business.industry, Attenuation, Bayesian probability, Iterative reconstruction, Inverse problem, Sensor fusion, 01 natural sciences, 030218 nuclear medicine & medical imaging, 010104 statistics & probability, 03 medical and health sciences, 0302 clinical medicine, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, Computer vision, Artificial intelligence, 0101 mathematics, Linear combination, business, Algorithm, ComputingMilieux_MISCELLANEOUS, Mathematics
Abstract

In this paper, we first introduce a Multi-Energy Computed Tomography (MECT) forward projection model based on the base material decomposition method. In this method, an object is considered into a linear combination of the fractions of several base materials weighted by X-ray beam energy functions. Then, three different data fusion inversion approaches are proposed to reconstruct the base material fractions. For the first pre-separation reconstruction approach, the base material decomposition is carried on in the projection space while in the second post-separation approach, the base material decomposition is carried on the attenuation coefficients. The third approach is a joint Bayesian inversion method. Finally, the reconstruction performances of the three reconstruction methods are compared on the simulated data.

Published
2011
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