Simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object

Paganin, David M.; Mayo, Sheridan C; Gureyev, T. E.; Miller, Peter; Wilkins, S. W.

doi:10.1046/j.1365-2818.2002.01010.x

Cited by 1,738 publications

(1,481 citation statements)

References 38 publications

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“…The reconstruction of the 3D volume was carried out first using a single-distance phase retrieval algorithm on the projections (after flat-and dark-field corrections), using the Paganin et al (2002) algorithm implemented in the ANKAphase software (Weitkamp et al, 2011). This procedure can be applied to data collected in the near-field region (in our measurement the sample-to-detector distance was ∼5 mm) using spatially coherent XR, such as the ones from synchrotron light sources.…”

Section: Sans/usansmentioning

confidence: 99%

Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

Beckingham

Steefel

Swift

et al. 2017

Geochimica et Cosmochimica Acta

121

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The rates of mineral dissolution reactions in porous media are difficult to predict, in part because of a lack of understanding of mineral reactive surface area in natural porous media. Common estimates of mineral reactive surface area used in reactive transport models for porous media are typically ad hoc and often based on average grain size, increased to account for surface roughness or decreased by several orders of magnitude to account for reduced surface reactivity of field as opposed to laboratory samples. In this study, accessible mineral surface areas are determined for a sample from the reservoir formation at the Nagaoka pilot CO2 injection site (Japan) using a multi-scale image analysis based on synchrotron Xray microCT, SEMQEMSCAN, XRD, SANS, and FIB-SEM. This analysis not only accounts for accessibility of mineral surfaces to macro-pores, but also accessibility through connected micro-pores in smectite, the most abundant clay mineral in this sample. While the imaging analysis reveals that most of the micro-and macro-pores are well connected, some pore regions are unconnected and thus inaccessible to fluid flow and diffusion. To evaluate whether mineral accessible surface area accurately reflects reactive surface area a flow-through core experiment is performed and modeled at the continuum scale. The core experiment is performed under conditions replicating the pilot site and the evolution of effluent solutes in the aqueous phase is tracked.Various reactive surface area models are evaluated for their ability to capture the observed effluent chemistry, beginning with parameter values determined as a best fit to a disaggregated sediment experiment (Beckingham et al., 2016) described previously.Simulations that assume that all mineral surfaces are accessible (as in the disaggregated sediment experiment) over-predict the observed mineral reaction rates, suggesting that a reduction of RSA by a factor of 10-20 is required to match the core flood experimental data. While the fit of the effluent chemistry (and inferred mineral dissolution rates) greatly improve when the pore-accessible mineral surface areas are used, it was also necessary to include highly reactive glass phases to match the experimental observations, in agreement with conclusions from the disaggregated sediment experiment. It is hypothesized here that the 10-20 reduction in reactive surface areas based on the limited pore accessibility of reactive phases in core flood experiment may be reasonable for poorly sorted and cemented sediments like those at the Nagaoka site, although this reflects pore rather than larger scale heterogeneity.

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Section: Sans/usansmentioning

confidence: 99%

Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

Beckingham

Steefel

Swift

et al. 2017

Geochimica et Cosmochimica Acta

121

View full text Add to dashboard Cite

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“…Therefore, the phase modulation information can be used to reconstruct the 3D structure in yielding much higher contrast than the amplitude modulation. This is called X-ray phase-contrast imaging technique [5,6] and the phase information is typically accomplished through the phase-retrieval algorithm [7,8].…”

Section: Tomography Reconstructionmentioning

confidence: 99%

Fast synchrotron X-ray tomography study of the rod packing structures

Zhang¹,

Xia²,

Sun³

et al. 2013

AIP Conference Proceedings

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“…In this paper, we use a phase retrieval approach 17,27 that has been adapted for use with a polychromatic source 18 …”

Section: A Phase Retrieval Algorithmmentioning

confidence: 99%

“…Propagation-based methods developed include those suitable for the inversion of data measured in the near Fresnel regime, 12 the intermediate Fresnel regime 13,14 and, more recently, in the far field. 15,16 Methods that use an assumption of sample homogeneity 17 and methods that incorporate polychromaticity in the source have also been developed. 18 In phase retrieval (PR) tomography, the projected intensity data in each angular position may be subjected to phase retrieval, which in turn may be reconstructed to obtain the three dimensional distribution of the sample phase.…”

Section: Introductionmentioning

confidence: 99%

Enhanced x-ray imaging for a thin film cochlear implant with metal artefacts using phase retrieval tomography

Arhatari

Harris

Paolini

et al. 2012

Journal of Applied Physics

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. (2012). Enhanced x-ray imaging for a thin film cochlear implant with metal artefacts using phase retrieval tomography. Journal of Applied Physics, 111 (11), 114904-1-114904-6. Enhanced x-ray imaging for a thin film cochlear implant with metal artefacts using phase retrieval tomography AbstractPhase retrieval tomography has been successfully used to enhance imaging in systems that exhibit poor absorption contrast. However, when highly absorbing regions are present in a sample, so-called metal artefacts can appear in the tomographic reconstruction. We demonstrate that straightforward approaches for metal artefact reconstruction, developed in absorption contrast tomography, can be applied when using phase retrieval. Using a prototype thin film cochlear implant that has high and low absorption components made from iridium (or platinum) and plastic, respectively, we show that segmentation of the various components is possible and hence measurement of the electrode geometry and relative location to other regions of interest can be achieved. 2012 American Institute of Physics. Phase retrieval tomography has been successfully used to enhance imaging in systems that exhibit poor absorption contrast. However, when highly absorbing regions are present in a sample, so-called metal artefacts can appear in the tomographic reconstruction. We demonstrate that straightforward approaches for metal artefact reconstruction, developed in absorption contrast tomography, can be applied when using phase retrieval. Using a prototype thin film cochlear implant that has high and low absorption components made from iridium (or platinum) and plastic, respectively, we show that segmentation of the various components is possible and hence measurement of the electrode geometry and relative location to other regions of interest can be achieved. V C 2012 American Institute of Physics. [http://dx

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Simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object

Cited by 1,738 publications

References 38 publications

Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

Fast synchrotron X-ray tomography study of the rod packing structures

Enhanced x-ray imaging for a thin film cochlear implant with metal artefacts using phase retrieval tomography

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