Automatic processing of multimodal tomography datasets

Parsons, Aaron; Price, Stephen W. T.; Wadeson, Nicola; Basham, Mark; Beale, Andrew M.; Ashton, Alun; Mosselmans, J. Frederick W.; Quinn, Paul D.

doi:10.1107/s1600577516017756

Cited by 14 publications

(10 citation statements)

References 25 publications

(15 reference statements)

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“…MMX-I, TomoPy), not all are suitable for the reconstruction of XRD-CT due to the additional data dimension [28,29]. Savu, developed by Diamond Light Source, is designed with these multimodal data in mind, and EasyDD is also suitable for processing XRD-CT [30][31][32]. As well as processing and reconstructing the data in a practical timescale (i.e.…”

Section: Discussionmentioning

confidence: 99%

X-ray physico-chemical imaging during activation of cobalt-based Fischer–Tropsch synthesis catalysts

Beale

Jacques

Michiel

et al. 2017

Phil. Trans. R. Soc. A.

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The imaging of catalysts and other functional materials under reaction conditions has advanced significantly in recent years. The combination of the computed tomography (CT) approach with methods such as X-ray diffraction (XRD), X-ray fluorescence (XRF) and X-ray absorption near-edge spectroscopy (XANES) now enables local chemical and physical state information to be extracted from within the interiors of intact materials which are, by accident or design, inhomogeneous. In this work, we follow the phase evolution during the initial reduction step(s) to form Co metal, for Co-containing particles employed as Fischer–Tropsch synthesis (FTS) catalysts; firstly, working at small length scales (approx. micrometre spatial resolution), a combination of sample size and density allows for transmission of comparatively low energy signals enabling the recording of ‘multimodal’ tomography, i.e. simultaneous XRF–CT, XANES–CT and XRD–CT. Subsequently, we show high-energy XRD–CT can be employed to reveal extent of reduction and uniformity of crystallite size on millimetre-sized TiO2 trilobes. In both studies, the CoO phase is seen to persist or else evolve under particular operating conditions and we speculate as to why this is observed.This article is part of a discussion meeting issue ‘Providing sustainable catalytic solutions for a rapidly changing world’.

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Section: Discussionmentioning

confidence: 99%

X-ray physico-chemical imaging during activation of cobalt-based Fischer–Tropsch synthesis catalysts

Beale

Jacques

Michiel

et al. 2017

Phil. Trans. R. Soc. A.

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“…Reconstruction was performed separately on a slice-by-slice basis. The STXM data was additionally used to correct the fluorescent intensity for sample absorption, taking into account the sample composition, density, and energies of the incident and fluorescent X-rays (as detailed in ref ). Using Savu, each XRD image was calibrated (using a LaB 6 reference material), and data azimuthally integrated from 2D images to 1D patterns.…”

Section: Methodsmentioning

confidence: 79%

“…Tomography data was processed using the Savu tomography reconstruction pipeline and DAWN . All data were reconstructed using the filtered back projection method.…”

Section: Methodsmentioning

confidence: 99%

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In Situ Multimodal 3D Chemical Imaging of a Hierarchically Structured Core@Shell Catalyst

et al. 2017

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A Cu/ZnO/AlO@ZSM-5 core@shell catalyst active for one-step conversion of synthesis gas to dimethyl ether (DME) was imaged simultaneously and in situ using synchrotron-based micro X-ray fluorescence (μ-XRF), X-ray diffraction (μ-XRD), and scanning transmission X-ray microscopy (STXM) computed tomography (CT) with micrometer spatial resolution. An identical sample volume was imaged stepwise, first under oxidizing and reducing atmospheres (imitating calcination and activation processes), and then under model reaction conditions for DME synthesis (H:CO:CO ratio of 16:8:1, up to 250 °C). The multimodal imaging methods offered insights into the active metal structure and speciation within the catalyst, and allowed imaging of both the catalyst core and zeolite shell in a single acquisition. Dispersion of nanosized Cu species was observed in the catalyst core during reduction, with formation of a metastable Cu phase at the core-shell interface. Under DME reaction conditions at 1 bar, the coexistence of Cu in the active catalyst core together with partially oxidized Cu species was unraveled. The zeolite shell and core-shell interface remained stable under all conditions, preserving the bifunctional nature of the catalyst. These observations are inaccessible using standard bulk techniques like X-ray absorption spectroscopy (XAS) and XRD, demonstrating the potential of multimodal in situ X-ray CT for characterization of hierarchically designed materials, which stand to benefit tremendously from such 3D spatially resolved measurements.

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“…Different imaging techniques in tomography have different characteristics that strongly depend on the specific data acquisition setup and the imaged tissue/material. Hence it is a major issue (and at the heart of current research, see, e.g., [10,14,27,34,36,39,43]) to improve the resolution of an image by combining different imaging techniques. In general it is, however, not clear, how this can actually be performed efficiently.…”

Section: Introductionmentioning

confidence: 99%

On Double-Resolution Imaging and Discrete Tomography

Alpers¹,

Gritzmann²

2018

SIAM J. Discrete Math.

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Super-resolution imaging aims at improving the resolution of an image by enhancing it with other images or data that might have been acquired using different imaging techniques or modalities. In this paper we consider the task of doubling, in each dimension, the resolution of grayscale images of binary objects by fusion with double-resolution tomographic data that have been acquired from two viewing angles. We show that this task is polynomial-time solvable if the gray levels have been reliably determined. The problem becomes NP-hard if the gray levels of some pixels come with an error of ±1 or larger. The NP-hardness persists for any larger resolution enhancement factor. This means that noise does not only affect the quality of a reconstructed image but, less expectedly, also the algorithmic tractability of the inverse problem itself.

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Automatic processing of multimodal tomography datasets

Cited by 14 publications

References 25 publications

X-ray physico-chemical imaging during activation of cobalt-based Fischer–Tropsch synthesis catalysts

X-ray physico-chemical imaging during activation of cobalt-based Fischer–Tropsch synthesis catalysts

In Situ Multimodal 3D Chemical Imaging of a Hierarchically Structured Core@Shell Catalyst

On Double-Resolution Imaging and Discrete Tomography

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