23 May 2013 Geometic image formation for target identification in multi-energy computed tomography
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Recent years have seen growing interest in exploiting dual- and multi-energy measurements in computed tomog­ raphy (CT) in order to characterize material properties as well as object geometry. Materials characterization is performed by decomposing the scene into constitutive basis functions, such as Compton and photoelectric scattering functions used here. While well motivated physically, the joint recovery of the spatial distribution of photoelectric and Compton properties is severely complicated by the lack of sensitivity in the data to photoelec­ tric variations. Moreover, while we have prior knowledge of Compton and photoelectric coefficients for materials of interest, this prior knowledge is imperfect and the true physical properties may assume a range of values. We propose a model-based iterative approach which accounts for the polyenergetic nature of computed tomography and includes patch based regularization terms to stabilize inversion of photoelectric coefficients. Further, we use a level set-based method to provide high spatial resolution for materials of interest, allowing initial estimates of material properties to be adjusted within a user-specified range. Initial results indicate that this approach is promising for future dual- and multi-energy CT systems with enhanced material characterization capabilities, for use in airport baggage screening and potentially in medical imaging.
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Brian H. Tracey, Brian H. Tracey, Eric L. Miller, Eric L. Miller, "Geometic image formation for target identification in multi-energy computed tomography", Proc. SPIE 8746, Algorithms for Synthetic Aperture Radar Imagery XX, 87460T (23 May 2013); doi: 10.1117/12.2020668; https://doi.org/10.1117/12.2020668

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