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Temporal sparsity exploiting nonlocal regularization for 4D computed tomography reconstruction

Kazantsev, D; Guo, E; Kaestner, A; Lionheart, WRB; Bent, J; Withers, PJ; Lee, PD; (2016) Temporal sparsity exploiting nonlocal regularization for 4D computed tomography reconstruction. Journal of X-Ray Science and Technology , 24 (2) pp. 207-219. 10.3233/XST-160546. Green open access

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Abstract

X-ray imaging applications in medical and material sciences are frequently limited by the number of tomographic projections collected. The inversion of the limited projection data is an ill-posed problem and needs regularization. Traditional spatial regularization is not well adapted to the dynamic nature of time-lapse tomography since it discards the redundancy of the temporal information. In this paper, we propose a novel iterative reconstruction algorithm with a nonlocal regularization term to account for time-evolving datasets. The aim of the proposed nonlocal penalty is to collect the maximum relevant information in the spatial and temporal domains. With the proposed sparsity seeking approach in the temporal space, the computational complexity of the classical nonlocal regularizer is substantially reduced (at least by one order of magnitude). The presented reconstruction method can be directly applied to various big data 4D (x, y, z+time) tomographic experiments in many fields. We apply the proposed technique to modelled data and to real dynamic X-ray microtomography (XMT) data of high resolution. Compared to the classical spatio-temporal nonlocal regularization approach, the proposed method delivers reconstructed images of improved resolution and higher contrast while remaining significantly less computationally demanding.

Type: Article
Title: Temporal sparsity exploiting nonlocal regularization for 4D computed tomography reconstruction
Open access status: An open access version is available from UCL Discovery
DOI: 10.3233/XST-160546
Publisher version: http://dx.doi.org/10.3233/XST-160546
Language: English
Additional information: This article is published online with Open Access and distributed under the terms of the Creative Commons Attribution Non-Commercial License.
Keywords: Iterative reconstruction, spatio-temporal regularization, time-lapse, nonlocal graphs, p-Laplacian, material science, X-ray microtomography, big data
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/10049208
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