Dr. Loïc Denis Profile

Dr. Loïc Denis

Astronomer at Univ Jean Monnet Saint-Etienne

SPIE Involvement:

Author

Publications (18)

Proceedings Article | 30 August 2022 Presentation + Paper

Presentation + Paper

Solar wavefront sensing at THEMIS with self-calibrated reference image and estimation of the noise covariance

Michel Tallon, Éric Thiébaut, Isabelle Tallon-Bosc, Bernard Gelly, Loïc Denis

Proceedings Volume 12185, 121852J (2022) https://doi.org/10.1117/12.2630379

KEYWORDS: Optimization (mathematics), Mathematical modeling, Solar telescopes, Motion measurement, Inverse problems, Wavefront sensors, Error analysis, Adaptive optics, Calibration, Image sensors, Image analysis, Telescopes, Sensors, Sun, Image processing

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Proceedings Article | 30 August 2022 Poster + Paper

Poster + Paper

Unsupervised blind-deconvolution with optimal scaling applied to astronomical data

Samuel Thé, Éric Thiébaut, Loïc Denis, Ferréol Soulez

Proceedings Volume 12185, 121853W (2022) https://doi.org/10.1117/12.2630245

KEYWORDS: Point spread functions, Deconvolution, Data modeling, Inverse problems, Astronomy, Algorithm development, Spatial resolution, Reconstruction algorithms

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Proceedings Article | 30 August 2022 Presentation + Paper

Presentation + Paper

Beyond FRiM, ASAP: a family of sparse approximation for covariance matrices and preconditioners

Éric Thiébaut, Michel Tallon, Samuel Thé, Loïc Denis

Proceedings Volume 12185, 121852Q (2022) https://doi.org/10.1117/12.2630192

KEYWORDS: Wavefronts, Matrices, Fractal analysis, Silicon, Wavefront reconstruction, Turbulence, Statistical modeling, Statistical analysis, Reconstruction algorithms

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Proceedings Article | 30 August 2022 Poster + Paper

Poster + Paper

Long-slit spectroscopy characterization of substellar objects with the EXOSPEC algorithm

Samuel Thé, Éric Thiébaut, Loïc Denis, Ferréol Soulez, Maud Langlois

Proceedings Volume 12185, 121853Q (2022) https://doi.org/10.1117/12.2630171

KEYWORDS: Data modeling, Point spread functions, Calibration, Sensors, Stars, Coronagraphy, Principal component analysis, Spectroscopy, Inverse problems

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Proceedings Article | 30 August 2022 Poster + Paper

Poster + Paper

Multispectral image reconstruction of faint circumstellar environments from high contrast angular spectral differential imaging (ASDI) data

Olivier Flasseur, Samuel Thé, Loïc Denis, Éric Thiébaut, Maud Langlois

Proceedings Volume 12185, 121853U (2022) https://doi.org/10.1117/12.2630362

KEYWORDS: Reconstruction algorithms, Statistical analysis, Data modeling, Statistical modeling

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Proceedings Article | 20 May 2022 Presentation

Presentation

Focus plane estimation in digital holographic microscopy

Corinne Fournier, Dylan Brault, Thomas Olivier, Nicolas Faure, Sophie Dixneuf, Louis Thibon, Loic Mees, Loïc Denis

Proceedings Volume PC12136, PC1213615 (2022) https://doi.org/10.1117/12.2623071

KEYWORDS: Digital holography, Holography, Microscopy, Inverse optics, Particles, Inverse problems, Statistical modeling, Optical signal processing, Holograms, Calibration

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Proceedings Article | 3 April 2020 Presentation

Presentation

Building an inverse approach for the reconstruction of in-line holograms: a parallel with Fienup’s phase retrieval technique (Conference Presentation)

Fabien Momey, Loïc Denis, Thomas Olivier, Corinne Fournier

Proceedings Volume 11351, 113510X (2020) https://doi.org/10.1117/12.2559085

KEYWORDS: Holograms, Phase retrieval, Inverse problems, Data modeling, Reconstruction algorithms, Image processing, Diffraction, Optimization (mathematics), Convex optimization, Physics

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In this paper, we propose to present the general ingredients involved in an inverse problems methodology dedicated to the reconstruction of in-line holograms, and compare it with the classical Gercherg-Saxton or Fienup alternating projections strategies for phase retrieval [1,2,3]. An inverse approach [4,5] consists in retrieving an optimal solution to a reconstruction/estimation problem from a dataset, knowing an approximate model of its formation process. The problem is generally formulated as an optimization problem that aims at fitting the model to the data, while favoring a priori knowledge on the targeted information using regularizations and constraints. An appropriate resolution method has to be designed, based on a convex optimization framework. We develop the end-to-end inverse problems methodology on a case-study : the reconstruction of an in-line hologram of a collection of weakly dephasing objects. This simple problem allows us to explain current physical considerations (type of objects, diffraction physics) to derive the appropriate model, and to present classical constraints and regularizations that can be used in image reconstruction. Starting from these ingredients, we introduce a simple yet efficient method to solve this inverse problem, belonging to the class of proximal gradient algorithms [6,7]. A special focus is made on the connections between the numerous alternating projections strategies derived from Fienup’s phase retrieval technique and the inverse problems framework. In particular, an interpretation of Fienup’s algorithm as iterates of a proximal gradient descent for a particular cost function is given. We discuss the advantages provided by the inverse problems methodology. We illustrate both strategies on reconstructions from simulated and experimental holograms of micrometric beads. The results show that the transition from alternating projection techniques to the inverse problems formulation is straightforward and advantageous.

Proceedings Article | 30 March 2020 Presentation

Presentation

Accounting for the nonstationary correlated noise in digital holography (Conference Presentation)

Olivier Flasseur, Loïc Denis, Éric Thiébaut, Thomas Olivier, Corinne Fournier

Proceedings Volume 11351, 1135113 (2020) https://doi.org/10.1117/12.2559941

KEYWORDS: Digital holography, Signal detection, Diffraction, Reflection, Optical components, Statistical analysis, Algorithm development, Detection and tracking algorithms, Holography, Microscopes

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Proceedings Article | 30 March 2020 Presentation + Paper

Presentation + Paper

Spherical object segmentation in digital holographic microscopy by deep-learning

Carlos Valadares, Dylan Brault, Loïc Denis, Corinne Fournier

Proceedings Volume 11351, 1135120 (2020) https://doi.org/10.1117/12.2559206

KEYWORDS: Image segmentation, Holograms, Digital holography, Holography, Neural networks, Inverse problems, Optical spheres, Optical simulations

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Proceedings Article | 18 July 2018 Presentation + Paper

Presentation + Paper

Innovative real-time processing for solar adaptive optics

Éric Thiébaut, Michel Tallon, Loïc Denis, Maud Langlois, Clémentine Béchet, Gil Moretto, Bernard Gelly

Proceedings Volume 10703, 107031I (2018) https://doi.org/10.1117/12.2313776

KEYWORDS: Adaptive optics, Wavefront sensors, Linear filtering, Deformable mirrors, Wavefronts, Scintillation, Data modeling, Image resolution, Actuators, Control systems

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Proceedings Article | 10 July 2018 Paper

Paper

Exoplanet detection in angular and spectral differential imaging: local learning of background correlations for improved detections

Olivier Flasseur, Loïc Denis, Éric Thiébaut, Maud Langlois

Proceedings Volume 10703, 107032R (2018) https://doi.org/10.1117/12.2313601

KEYWORDS: Exoplanets, Signal to noise ratio, Statistical analysis, Stars, Detection and tracking algorithms, Exoplanetary science, Point spread functions, Binary data, Spectrographs, Imaging systems

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Proceedings Article | 24 May 2018 Paper

Paper

Quantitative phase retrieval reconstruction from in-line hologram using a new proximal operator: application to microscopy of bacteria and tracking of droplets

Fabien Momey, Frédéric Jolivet, Loïc Denis, Corinne Fournier, Loïc Méès, Nicolas Faure, Frédéric Pinston

Proceedings Volume 10677, 106770M (2018) https://doi.org/10.1117/12.2311312

KEYWORDS: Holograms, Inverse problems, Phase retrieval, Reconstruction algorithms, Microscopy, Digital holography, Inverse imaging problems, Phase imaging, Fluid dynamics, Microbiology

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Proceedings Article | 24 May 2018 Presentation + Paper

Presentation + Paper

Improving color lensless microscopy reconstructions by self-calibration

Olivier Flasseur, Frédéric Jolivet, Fabien Momey, Loïc Denis, Corinne Fournier

Proceedings Volume 10677, 106771A (2018) https://doi.org/10.1117/12.2300005

KEYWORDS: Sensors, Opacity, Semiconductor lasers, Optical filters, Reconstruction algorithms, Digital holography, Color image processing

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Proceedings Article | 27 July 2016 Paper

Paper

Fast and robust exo-planet detection in multi-spectral, multi-temporal data

Éric Thiébaut, Loïc Denis, Laurent Mugnier, André Ferrari, David Mary, Maud Langlois, Faustine Cantalloube, Nicholas Devaney

Proceedings Volume 9909, 990957 (2016) https://doi.org/10.1117/12.2233405

KEYWORDS: Sensors, Planets, Optical spheres, Gemini Planet Imager, Surface conduction electron emitter displays, Point spread functions, Data modeling, Signal detection, Fourier transforms, Signal to noise ratio

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Proceedings Article | 27 July 2016 Paper

Paper

Spatially variant PSF modeling and image deblurring

Éric Thiébaut, Loïc Denis, Ferréol Soulez, Rahul Mourya

Proceedings Volume 9909, 99097N (2016) https://doi.org/10.1117/12.2233647

KEYWORDS: Adaptive optics, Point spread functions, Astronomy, Data modeling, Convolution, Calibration, Galactic astronomy, Iterative methods, Stars, Instrument modeling

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Proceedings Article | 14 February 2013 Paper

Paper

Robust registration of electron tomography projections without fiducial markers

Viet-Dung Tran, Maxime Moreaud, Éric Thiébaut, Loïc Dénis, Jean-Marie Becker

Proceedings Volume 8657, 86570R (2013) https://doi.org/10.1117/12.2001128

KEYWORDS: Transmission electron microscopy, Reconstruction algorithms, Electron tomography, Image registration, Sensors, Inverse problems, Zeolites, 3D modeling, Optimization (mathematics), Gold

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Proceedings Article | 20 May 2011 Paper

Paper

Inverse problem approaches for digital hologram reconstruction

Corinne Fournier, Loic Denis, Eric Thiebaut, Thierry Fournel, Mozhdeh Seifi

Proceedings Volume 8043, 80430S (2011) https://doi.org/10.1117/12.885761

KEYWORDS: Holograms, Digital holography, Diffraction, 3D modeling, 3D image reconstruction, Sensors, Inverse problems, 3D image processing, Reconstruction algorithms, Holography

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Proceedings Article | 17 September 2005 Paper

Paper

Twin-image noise reduction by phase retrieval in in-line digital holography

Loic Denis, Corinne Fournier, Thierry Fournel, Christophe Ducottet

Proceedings Volume 5914, 59140J (2005) https://doi.org/10.1117/12.617405

KEYWORDS: Holograms, Digital holography, Holography, 3D image reconstruction, Particles, Phase retrieval, Reconstruction algorithms, Denoising, Deconvolution, Electronic filtering

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Showing 5 of 18 publications

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