X-ray dark-field tomography using edge-illumination

Doherty, Adam; Savidis, Savvis; Astolfo, Alberto; Massimi, Lorenzo; Djurabekova, Nargiza; Leon, Carlos Navarrete; Gerli, M; Iacoviello, Francesco; Shearing, Paul R.; Norman, D; Williams, Mark A.; Olivo, Alessandro; Endrizzi, Marco

doi:10.1117/12.2632731

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…Further improvements to the method by extending the method to account for offsets in the sample mask position due to drift or vibrations are presented in [79,80], showcasing the increased flexibility of iterative reconstruction methods. The existing joint reconstruction methods for EI do not include dark field reconstructions, which can provide additional information on sample properties [81]. Furthermore, no investigation of optimal solvers for the objective function was performed in [77].…”

Section: Edge Illumination Ct Reconstructionmentioning

confidence: 99%

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Improved X-ray CT reconstruction techniques with non-linear imaging models

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Section: Edge Illumination Ct Reconstructionmentioning

confidence: 99%

“…This method achieves a similar flexibility in acquisition setup for EI as reported in [78] for GBI. However, this method does not include scatter reconstructions, which can provide additional information on sample properties [81]. Moreover, no investigation into different suitable solvers for the objective function was performed in [77].…”

Section: Introductionmentioning

confidence: 99%

Improved X-ray CT reconstruction techniques with non-linear imaging models

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Increased material differentiation through multi-contrast x-ray imaging: a preliminary evaluation of potential applications to the detection of threat materials

et al. 2023

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Most material discrimination in security inspections is based on dual-energy x-ray imaging, which enables the determination of a material’s effective atomic number (Z eff) as well as electron density and its consequent classification as organic or inorganic. Recently phase-based “dark-field” x-ray imaging approaches have emerged that are sensitive to complementary features of a material, namely its unresolved microstructure. It can therefore be speculated that their inclusion in the security-based imaging could enhance material discrimination, for example of materials with similar electron densities and Z eff but different microstructures. In this paper, we present a preliminary evaluation of the advantages that such a combination could bear. Utilising an energy-resolved detector for a phase-based dark-field technique provides dual-energy attenuation and dark-field images simultaneously. In addition, since we use a method based on attenuating x-ray masks to generate the dark-field images, a fifth (attenuation) image at a much higher photon energy is obtained by exploiting the x-rays transmitted through the highly absorbing mask septa. In a first test, a threat material is imaged against a non-threat one, and we show how their discrimination based on maximising their relative contrast through linear combinations of two and five imaging channels leads to an improvement in the latter case. We then present a second example to show how the method can be extended to discrimination against more than one non-threat material, obtaining similar results. Albeit admittedly preliminary, these results indicate that significant margins of improvement in material discrimination are available by including additional x-ray contrasts in the scanning process.

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Joint multi-contrast CT for edge illumination X-ray phase contrast imaging using split Barzilai-Borwein steps

Six,

Renders,

De Beenhouwer

et al. 2024

Opt. Express

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Edge illumination (EI) is an X-ray imaging technique that, in addition to conventional absorption contrast, provides refraction and scatter contrast. It relies on an absorption mask in front of the sample that splits the X-ray beam into beamlets, which hits a second absorption mask positioned in front of the detector. The sample mask is then shifted in multiple steps with respect to the detector mask, thereby measuring an illumination curve per detector element. The width, position, and area of this curve estimated with and without the sample in the beam is then compared, which ultimately provides absorption, refraction, and scatter contrast for each detector pixel. From the obtained contrast sinograms, three contrast tomograms can be computed. In summary, conventional EI relies on a two-stage process comprised of a computational and time intensive contrast retrieval process, followed by tomographic reconstruction. In this work, a novel joint reconstruction method is proposed, which utilizes a combined forward model to reconstruct the three contrasts simultaneously, without the need for an intermediate contrast retrieval step. Compared to the state-of-the-art, this approach reduces reconstruction times, as the retrieval step is skipped and allows a much more flexible acquisition scheme, as there is no need to sample a full illumination curve at each projection angle. The proposed method is shown to improve reconstruction quality on subsampled datasets, enabling the reconstruction of three contrasts from single-shot datasets.

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X-ray dark-field tomography using edge-illumination

Cited by 3 publications

References 14 publications

Improved X-ray CT reconstruction techniques with non-linear imaging models

Improved X-ray CT reconstruction techniques with non-linear imaging models

Increased material differentiation through multi-contrast x-ray imaging: a preliminary evaluation of potential applications to the detection of threat materials

Joint multi-contrast CT for edge illumination X-ray phase contrast imaging using split Barzilai-Borwein steps

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