Xia Y, Berger M, Bauer S, Hu S, Aichert A, Maier A (2017)
Publication Type: Journal article
Publication year: 2017
Publisher: Hindawi Limited
Book Volume: 2017
Pages Range: 1-14
Journal Issue: 1867025
URI: https://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2017/Xia17-AIE.pdf
DOI: 10.1155/2017/1867025
We improve data extrapolation for truncated computed tomography (CT) projections by using Helgason-Ludwig (HL) consistency conditions that mathematically describe the overlap of information between projections. First, we theoretically derive a 2D Fourier representation of the HL consistency conditions from their original formulation (projection moment theorem), for both parallel-beam and fan-beam imaging geometry. The derivation result indicates that there is a zero energy region forming a double-wedge shape in 2D Fourier domain. This observation is also referred to as the Fourier property of a sinogram in the previous literature. The major benefit of this representation is that the consistency conditions can be efficiently evaluated via 2D fast Fourier transform (FFT). Then, we suggest a method that extrapolates the truncated projections with data from a uniform ellipse of which the parameters are determined by optimizing these consistency conditions. The forward projection of the optimized ellipse can be used to complete the truncation data. The proposed algorithm is evaluated using simulated data and reprojections of clinical data. Results show that the root mean square error (RMSE) is reduced substantially, compared to a state-of-the-art extrapolation method.
APA:
Xia, Y., Berger, M., Bauer, S., Hu, S., Aichert, A., & Maier, A. (2017). An Improved Extrapolation Scheme for Truncated CT Data Using 2D Fourier-Based Helgason-Ludwig Consistency Conditions. International Journal of Biomedical Imaging, 2017(1867025), 1-14. https://doi.org/10.1155/2017/1867025
MLA:
Xia, Yan, et al. "An Improved Extrapolation Scheme for Truncated CT Data Using 2D Fourier-Based Helgason-Ludwig Consistency Conditions." International Journal of Biomedical Imaging 2017.1867025 (2017): 1-14.
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