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Directional dark-field implicit x-ray speckle tracking using an anisotropic-diffusion Fokker-Planck equation
Konstantin Mikhailovitch Pavlov,David M. Paganin,Kaye S. Morgan,Heyang,Sebastien Berujon,Laurène Quénot,Emmanuel Brun +6 more
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TLDR
In this paper, an anisotropic-diffusion Fokker-Planck approach is used to model the bifurcated x-ray energy flow in macroscopic-sized non-crystalline samples.Abstract:
When a macroscopic-sized non-crystalline sample is illuminated using coherent x-ray radiation, a bifurcation of photon energy flow may occur. The coarse-grained complex refractive index of the sample may be considered to attenuate and refract the incident coherent beam, leading to a coherent component of the transmitted beam. Spatially-unresolved sample microstructure, associated with the fine-grained components of the complex refractive index, introduces a diffuse component to the transmitted beam. This diffuse photon-scattering channel may be viewed in terms of position-dependent fans of ultra-small-angle x-ray scatter. These position-dependent fans, at the exit surface of the object, may under certain circumstances be approximated as having a locally-elliptical shape. By using an anisotropic-diffusion Fokker-Planck approach to model this bifurcated x-ray energy flow, we show how all three components (attenuation, refraction and locally-elliptical diffuse scatter) may be recovered. This is done via x-ray speckle tracking, in which the sample is illuminated with spatially-random x-ray fields generated by coherent illumination of a spatially-random membrane. The theory is developed, and then successfully applied to experimental x-ray data.read more
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X-ray phase imaging with a paper analyzer
TL;DR: In this paper, a simple x-ray phase imaging method that utilizes the sample-induced distortion of a high contrast random intensity pattern to quantitatively retrieve the two-dimensional phase map at the exit surface of a coherently illuminated sample is presented.
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Dark-field X-ray microscopy for multiscale structural characterization
Hugh Simons,A. King,Wolfgang Ludwig,Carsten Detlefs,Wolfgang Pantleon,Søren Schmidt,Irina Snigireva,Anatoly Snigirev,Henning Friis Poulsen +8 more
TL;DR: Dark-field X-ray microscopy; a non-destructive microscopy technique for the three-dimensional mapping of orientations and stresses on lengths scales from 100 nm to 1 mm within embedded sampling volumes is presented.
Journal ArticleDOI
Single-shot x-ray differential phase-contrast and diffraction imaging using two-dimensional transmission gratings
TL;DR: An x-ray differential phase-contrast imaging method based on two-dimensional transmission gratings that are directly resolved by an x-rays that obviates the need for multiple exposures and separate measurements for different directions and thereby accelerates imaging speed.
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An evaluation of optical flow algorithms for background oriented schlieren imaging
TL;DR: Experiments with both synthetic and real datasets show that the performance of BOS systems can be significantly improved through a combination of optical flow algorithms and multiscale background.
Journal ArticleDOI
An introduction to ghost imaging: quantum and classical.
Miles J. Padgett,Robert W. Boyd +1 more
TL;DR: Ghost imaging has been a subject of interest to the quantum optics community for the past 20 years and is now recognized as being implementable in both single- and many-photon number regimes.
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