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Tomography is an imaging technique that works by reconstructing a scene from acquired data in the form of line integrals of the imaging domain. A fundamental underlying assumption in the reconstruction procedure is the precise alignment of…

Numerical Analysis · Mathematics 2018-07-13 Toby Sanders

New lensless diffractive X-ray technic for micro-scale imaging of biological tissue is based on quantitative phase retrieval schemes. By incorporating refraction, this method yields improved contrast compared to purely absorption-based…

Numerical Analysis · Mathematics 2018-03-28 Victor Palamodov

X-ray phase-contrast imaging enhances soft tissue visualization by leveraging the phase shift of X-rays passing through materials. It permits to minimize radiation exposure due to high contrast, as well as high resolution imaging limited by…

Optics · Physics 2024-03-13 Emilie Pietersoone , Jean Michel Létang , Simon Rit , Max Langer

We discuss the use of parametric phase-diverse phase retrieval as an in-situ high-fidelity wavefront measurement method to characterize and optimize the transmitted wavefront of a high-contrast coronagraphic instrument. We apply our method…

Instrumentation and Methods for Astrophysics · Physics 2019-03-06 Gregory R. Brady , Christopher Moriarty , Peter Petrone , Iva Laginja , Keira Brooks , Tom Comeau , Lucie Leboulleux , Remi Soummer

In this paper, we develop a novel phase retrieval approach to reconstruct x-ray differential phase shift induced by an object. A primary advantage of our approach is a higher-order accuracy over that with the conventional linear…

Medical Physics · Physics 2010-03-18 Wenxiang Cong , Ge Wang

X-ray speckles have been used for a wide variety of experiments, ranging from imaging (and tomography), wavefront sensing, spatial coherence measurements all the way to x-ray photon correlation spectroscopy (XPCS) and ptychography. In the…

Medical Physics · Physics 2024-04-19 Rafael Celestre , Laurene Quenot , Christopher Ninham , Emmanuel Brun , Luca Fardin

Sensitive to scattering from unresolved sample structures, the dark-field channel in full-field X-ray imaging provides complementary information to that offered by conventional attenuation and phase-contrast methods. A range of experimental…

Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the…

Applied Physics · Physics 2023-06-16 C. Gao , C. Hofer , T. J. Pennycook

Holographic coherent X-ray imaging enables nanoscale imaging of biological cells and tissues, rendering both phase and absorption contrast, i.e. real and imaginary parts of the refractive index. Unlike the standard model, which assumes a…

Analysis of PDEs · Mathematics 2026-05-29 Thorsten Hohage , Milad Karimi , Björn Müller

We develop a speckle-tracking method for x-ray phase-contrast imaging, based on the concept of geometric flow. This flow is a conserved current associated with deformation of illuminating x-ray speckles induced by passage through a sample.…

Medical Physics · Physics 2018-11-14 David M. Paganin , Helene Labriet , Emmanuel Brun , Sebastien Berujon

In x-ray computed tomography (CT) it is generally acknowledged that reconstruction methods exploiting image sparsity allow reconstruction from a significantly reduced number of projections. The use of such reconstruction methods is…

Numerical Analysis · Mathematics 2014-08-05 Jakob S. Jørgensen , Emil Y. Sidky , Per Christian Hansen , Xiaochuan Pan

Achieving high spatial resolution is the goal of many imaging systems. Designing a high-resolution lens with diffraction-limited performance over a large field of view remains a difficult task in imaging system design. On the other hand,…

In this work, we compare one-step and two-step approaches for X-ray computed tomography (CT) scatter correction and density reconstruction. X-ray CT is an important imaging technique in medical and industrial applications. In many cases,…

Image and Video Processing · Electrical Eng. & Systems 2023-01-11 Alexander N. Sietsema , Michael T. McCann , Marc L. Klasky , Saiprasad Ravishankar

X-ray tomography has been studied in various fields. Although a great deal of effort has been directed at reconstructing the projection image set from a rigid-type specimen, little attention has been addressed to the reconstruction of…

Computational Physics · Physics 2018-07-04 Kyungtaek Jun , Dongwook Kim

Material decomposition in X-ray imaging uses the energy-dependence of attenuation to virtually decompose an object into specific constituent materials. X-ray phase contrast imaging is a developing technique that can enhance image contrast…

Diffractive lenses have recently been applied to the domain of multispectral imaging in the X-ray and UV regimes where they can achieve very high resolution as compared to reflective and refractive optics. Conventionally, spectral…

Image and Video Processing · Electrical Eng. & Systems 2020-05-26 Evan Widloski , Ulas Kamaci , Farzad Kamalabadi

A new method is developed for three-dimensional (3D) reconstruction of multi-material objects using propagation-based X-ray phase-contrast tomography (PB-CT) with phase retrieval via the contrast transfer function (CTF) formalism. The…

Medical Physics · Physics 2023-05-15 Darren A. Thompson , Yakov I. Nesterets , Konstantin M. Pavlov , Timur E. Gureyev

Propagation-based phase-contrast X-ray imaging (PB-PCXI) generates image contrast by utilizing sample-imposed phase-shifts. This has proven useful when imaging weakly-attenuating samples, as conventional attenuation-based imaging does not…

Set projection algorithms are a class of algorithms used in ptychography to help improve the quality of the reconstructed images. The set projection step is important because it helps to ensure that the reconstructed image satisfies the…

Signal Processing · Electrical Eng. & Systems 2023-11-21 Wenjie Mei , Andrew M. Maiden

The Fourier inversion of phased coherent diffraction patterns offers images without the resolution and depth-of-focus limitations of lens-based tomographic systems. We report on our recent experimental images inverted using recent…