Publications associées à Imaging with Coherent X-rays: From the Early Synchrotron Tests to SYNAPSE

A synthetic phase-contrast imaging diagnostic with spatial filtering for gyrokinetic simulations

Stephan Brunner, Stefano Coda, Gabriele Merlo, Aylwin Iantchenko, Justin Richard Ball

A Phase-contrast imaging (PCI) diagnostic provides measurements of line-integrated electron density fluctuations. Localisation along the laser beam path can be achieved with a spatial filter that selects the wave-vector directions of the fluctuations contr ...

2023

High sensitivity, incoherent differential imaging

Chiara Bonati

Microscopic visualisation of optically transparent samples has been a topic of interest for several decades. Features such as density or chemical composition can influence the optical phase of transmitted light, and phase contrast can reveal these structur ...

EPFL2022

3D reconstruction of weakly scattering objects from 2D intensity-only measurements using the Wolf transform

Demetri Psaltis, Ahmed Ayoub, Joowon Lim, Elizabeth Elena Antoine

A new approach to optical diffraction tomography (ODT) based on intensity measurements is presented. By applying the Wolf transform directly to intensity measurements, we observed unexpected behavior in the 3D reconstruction of the sample. Such a reconstru ...

2021

Robust Phase Unwrapping via Deep Image Prior for Quantitative Phase Imaging

Matthias Lütolf, Michaël Unser, Nathalie Brandenberg, Thanh-An Michel Pham, Fangshu Yang

Quantitative phase imaging (QPI) is an emerging label-free technique that produces images containing morphological and dynamical information without contrast agents. Unfortunately, the phase is wrapped in most imaging system. Phase unwrapping is the comput ...

2021

Brain micro-vasculature imaging: An unsupervised deep learning algorithm for segmenting mouse brain volume probed by high-resolution phase-contrast X-ray tomography

Anne Bonnin, Alessandra Patera, Marco Stampanoni

High-throughput synchrotron-based tomographic microscopy at third generation light sources allows to probe cm-sized samples at micrometer-resolution. In this work, we present an approach to image a full mouse brain. With Indian-ink as a contrast agent, it ...

WILEY2021

Optical phase contrast imaging of human retinal cells by changing the tissue refractive index

Christophe Moser, Mathieu Künzi, Timothé Laforest, Laura Emmanuelle Kowalczuk

Purpose : Based on oblique partially coherent illumination of transparent samples, we developed a simple custom Optical Phase Imaging (OPI) microscope providing a label-free, semi-quantitative phase contrast imaging. The aim of this study was to explore th ...

ASSOC RESEARCH VISION OPHTHALMOLOGY INC2020

Near-field phase profile and far-field contrast modulation for micro-lens arrays at the refraction limit

Toralf Scharf, Maryam Yousefi, Daniel Necesal

We investigate the far-field pattern generation for a micro-lens array (MLA) illuminated under different conditions. Plane wave and Gaussian beam illumination are considered for an MLA with a small diameter of 27 microns and 30 microns period. At these dim ...

2020

Improved susceptibility-weighted imaging for high contrast and resolution thalamic nuclei mapping at 7T

Meritxell Bach Cuadra, Elena Najdenovska, José Pedro Rebelo Ferreira Marques, Frédéric Gretsch, João Pedro Forjaco Jorge, Daniel Gallichan, Constantin Tuleasca

Purpose The thalamus is an important brain structure and neurosurgical target, but its constituting nuclei are challenging to image non-invasively. Recently, susceptibility-weighted imaging (SWI) at ultra-high field has shown promising capabilities for tha ...

Wiley2020

Fat navigators based retrospective motion correction strategies for brain magnetic resonance imaging

Frédéric Gretsch

Magnetic resonance resonance (MRI) is a widely used modality to obtain in vivo tissue information. Clinical applications are near countless, and almost all body parts can be examined using an MR scanner. As the method is non invasive, does not use ionizing ...

EPFL2020

Insights into image contrast from dislocations in ADF-STEM

Cécile Hébert, Emad Oveisi, Maria Chiara Spadaro

Competitive mechanisms contribute to image contrast from dislocations in annular dark-field scanning transmission electron microscopy (ADF-STEM). A clear theoretical understanding of the mechanisms underlying the ADF-STEM contrast is therefore essential fo ...

ELSEVIER SCIENCE BV2019

Multi T1-weighted contrast MRI with fluid and white matter suppression at 1.5 T

Giulio Gambarota, Tobias Kober

Introduction: The fluid and white matter suppression sequence (FLAWS) provides two T1-weighted co-registered datasets: a white matter (WM) suppressed contrast (FLAWS1) and a cerebrospinal fluid (CSF) suppressed contrast (FLAWS2). FLAWS has the potential to ...

ELSEVIER SCIENCE INC2019

Biomedical optical techniques for intracochlear cellular imaging

Marilisa Romito

Imaging the inner ear microanatomy is of great importance for the assessment of the state of the cells responsible for sound detection. Hearing disorders are mainly due to a malfunction of the cochlea, the bone containing the cells inside the inner ear. Un ...

EPFL2019

En face retinal imaging

Dino Carpentras

Retinal imaging is routinely used to provide information about vision health. Recent studies showed that retinal images can also provide information on general health (e.g. stress level), brain pathologies and attention. Depending on the target information ...

EPFL2018

Quantitative phase imaging in biomedicine

Christian Depeursinge

Quantitative phase imaging (QPI) has emerged as a valuable method for investigating cells and tissues. QPI operates on unlabelled specimens and, as such, is complementary to established fluorescence microscopy, exhibiting lower phototoxicity and no photobl ...

Nature Publishing Group2018

3D Reconstruction of Optical Diffraction Tomography Based on a Neural Network Model

Morteza Hasani Shoreh

Optical tomography has been widely investigated for biomedical imaging applications. In recent years, it has been combined with digital holography and has been employed to produce high quality images of phase objects such as cells. In this Thesis, we look ...

EPFL2018

Structural and functional brain imaging using extended-focus optical coherence tomography and microscopy

Paul James Marchand

Neuroimaging techniques aim at revealing the anatomy and functional organisation of cerebral structures. Over the past decades, functional magnetic resonance imaging (fMRI) has revolutionized our understanding of human cerebral physiology through its abili ...

EPFL2018

Gray-matter-specific MR imaging improves the detection of epileptogenic zones in focal cortical dysplasia: A new sequence called fluid and white matter suppression (FLAWS)

Tobias Kober, Thomas Yu, Nan Chen, Xin Chen

Objectives: To evaluate the diagnostic value and characteristic features of FCD epileptogenic zones using a novel sequence called fluid and white matter suppression (FLAWS). ...

ELSEVIER SCI LTD2018

Coherent imaging from bacteria to multicellular organisms

Séverine Coquoz

Structural and functional imaging of cells, tissues and organisms is crucial for understanding biomedical processes. Fluorescence microscopy is an established tool and has contributed to many discoveries in the life sciences. This technique provides molecu ...

EPFL2017

Direct unwrapped phase estimation in phase shifting interferometry using Levenberg-Marquardt algorithm

Pramod Rastogi, Rishikesh Dilip Kulkarni

An algorithm for the direct unwrapped phase estimation from the linearly phase shifted interferograms is presented. The temporal fringe intensity along each pixel is represented as a function of fringe amplitude, phase step and the searched phase. These pa ...

Iop Publishing Ltd2017

Variational Phase Imaging Using the Transport-of-Intensity Equation

Michaël Unser, Daniel Sage, Emrah Bostan, Masih Nilchian, Emmanuel Augustin Julien Froustey

We introduce a variational phase retrieval algorithm for the imaging of transparent objects. Our formalism is based on the transport-of-intensity equation (TIE), which relates the phase of an optical field to the variation of its intensity along the direct ...

IEEE2016