Artifact removal in the contour areas of SAXS-CT images by Tikhonov-L1 minimization

Ogawa, Hiroki; Ono, Shunsuke; Watanabe, Yuki; Nishikawa, Yukihiro; Nishitsuji, Shotaro; Kabe, Taizo; Takenaka, Mitsuru

doi:10.1107/s1600576721011523

Cited by 3 publications

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“…Reconstruction of the CT images from anisotropic SAXS patterns can provide orientation information for nanoscale structures. Although the spatial resolution in the reconstructed CT image is lower than that of SEM, SAXS-CT enables nondestructive evaluation of the heterogeneity of the oriented lamellar structures inside the sample. − …”

Section: Introductionmentioning

confidence: 99%

Distribution of Oriented Lamellar Structures in Injection-Molded High-Density Polyethylene Visualized via the Small Angle X-ray Scattering-Computed Tomography Method

et al. 2023

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Using the SAXS-CT method, which observed the spatial distribution of nanometer-scale structures on a micrometer scale, we investigated the orientation distribution of the lamellar structure of injection-molded HDPE. We reconstructed CT images in the plane perpendicular (X–Y) and the plane parallel to the injection direction (X–Z) from the SAXS intensities corresponding to the period of the lamellar structures. The CT image at a flow speed of 5 mm/s in the X–Y plane showed that the lamellar structures oriented in the injection direction mainly consisted of three layers: the skin layer, the subskin layer, and the core layer, based on their differences in the distribution states. The CT images in the X–Z plane showed that the distribution of the lamellar structures was oriented in the thickness direction in the subskin layer and part of the core layer. Furthermore, we observed the distribution of the lamellar structure oriented in the injection direction with increasing injection speed, v, to evaluate the size change in each layer. The size of the skin layer thickness decreased heterogeneously in the CT images in the X–Y plane from v = 5 up to 40 mm/s. However, the distributions and thickness variations in the subskin and core layers were different from those in the skin layer due to the balance of the elongation, relaxation, and fountain flow effects.

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Section: Introductionmentioning

confidence: 99%

Distribution of Oriented Lamellar Structures in Injection-Molded High-Density Polyethylene Visualized via the Small Angle X-ray Scattering-Computed Tomography Method

et al. 2023

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Nanostructure distribution in multilayered Al alloy sheets analyzed by quantitative small-angle X-ray scattering tomography

Lin,

Okuda,

et al. 2024

Nuclear Instruments and Methods in Physics Research Section B:

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Tikhonov Regularization and Perturbation-Level Tuning for the CNM in Pharmacokinetics

et al. 2023

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In pharmacokinetics, the clinical information collected from the patient is often much less than the complexity of the patient's internal operations, hence the undetermined inverse problem has emerged as a challenge to solve it and find multiple possible point sets for considering the many possible implications of drug kinetics in the patient's body. This paper suggests two enhanced schemes for the early cluster Newton method (CNM) to concomitantly explore a great solutions number for the inverse parameter determination in pharmacokinetics. The first scheme is the application of Tikhonov regularization in order to deal with the overdetermined system for hyperplane fitting in the CNM, and the second is an effective iterative strategy by tuning perturbation-level for the CNM. As a result of Tikhonov's filtering operation, the singular values of lower order than the regularization parameter, which are to blame for the instability of the matrix equation, are efficiently eliminated. With perturbation-level tuning, following every iteration, as the point cluster (PoC) gets near the solution manifold (SoM), it is essential to lessen the level of perturbation in the patient's clinical measurement data and this is suited for a numerical stabilization. Numerical simulation scenarios of two schemes have revealed that these suggested schemes can lower the iterations number and computed time, and PoC move more steadily towards the solutions manifold.INDEX TERMS Tikhonov regularization, physiologically based pharmacokinetics, pharmacokinetics, cluster Newton method, inverse problem.

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Artifact removal in the contour areas of SAXS-CT images by Tikhonov-L1 minimization

Cited by 3 publications

References 33 publications

Distribution of Oriented Lamellar Structures in Injection-Molded High-Density Polyethylene Visualized via the Small Angle X-ray Scattering-Computed Tomography Method

Distribution of Oriented Lamellar Structures in Injection-Molded High-Density Polyethylene Visualized via the Small Angle X-ray Scattering-Computed Tomography Method

Nanostructure distribution in multilayered Al alloy sheets analyzed by quantitative small-angle X-ray scattering tomography

Tikhonov Regularization and Perturbation-Level Tuning for the CNM in Pharmacokinetics

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