Zhi W, Zou J, Zhao J, Xia X. Mineral quantitative characterization method based on basis material decomposition model by dual-energy computed tomography.
JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2023;
31:373-391. [PMID:
36641733 DOI:
10.3233/xst-221324]
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Abstract
BACKGROUND
Dual-energy computed tomography (DECT) can reconstruct electron density ρe and effective atomic number Zeff distribution for material discrimination. Image-domain basis material decomposition (IBMD) method is a widely used DECT method. However, IBMD method cannot be used for mineral identification directly due to limitations of complex basis material determination, beam hardening artifacts, and inherent errors caused by approximate empirical formulas.
OBJECTIVE
This study proposes an improved IBMD (IIBMD) method to overcome the above limitations.
METHODS
In IIBMD method, the composition of basis material is optimized to obtain accurate decomposition coefficients, which enables accurate ρe and Zeff distribution. Moreover, the thickness of basis material is optimized to reduce the effect of beam hardening. Furthermore, two formulas in place of empirical formulas are proposed to calculate ρe and Zeff. Finally, a threshold technique is applied to separate different mineral phases.
RESULTS
Numerical simulations and practical experiments using a photon-counting detector CT system are implemented to verify IIBMD method. Results show that the relative errors of ρe and Zeff for seven common minerals are down to 5%, lower than most of the existing DECT methods for rocks. Reasonable volume fraction results of mineral phases are thus obtained through threshold segmentation.
CONCLUSIONS
This study demonstrates that the proposed IIBMD method has high practical value in mineralogical identification.
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