DocumentCode :
1655536
Title :
Beam hardening correction via mass attenuation discretization
Author :
Renliang Gu ; Dogandzic, A.
Author_Institution :
ECpE Dept., Iowa State Univ., Ames, IA, USA
fYear :
2013
Firstpage :
1085
Lastpage :
1089
Abstract :
We develop a beam-hardening correction method for polychromatic x-ray computed tomography (CT) reconstruction based on mass attenuation coefficient discretization. We assume that the inspected object consists of an unknown single material and that the incident x-ray spectrum is unknown. In this case, the standard photon-energy discretization of the Beer´s law measurement equation leads to an excessive number of unknown parameters and scaling ambiguity. To obtain a parsimonious measurement model parametrization, we first rewrite the measurement equation in terms of integral expressions of the mass attenuation rather than photon energy. The resulting integrals can be discretized easily thanks to the fact that the range of mass attenuations is bounded and, in practice, fairly narrow. We then develop a constrained least-squares optimization approach for reconstructing the underlying object from log-scale measurements, where we impose the nonnegativity constraint to both the signal and the x-ray spectrum density estimates. We demonstrate the performance of the proposed method via a numerical example where we compare it with the standard filtered backprojection (FBP), which ignores the polychromatic nature of the measurements.
Keywords :
X-ray microscopy; computerised tomography; least squares approximations; medical signal processing; signal reconstruction; Beer law measurement equation; CT reconstruction; FBP; X-ray spectrum density estimates; beam-hardening correction method; constrained least-squares optimization approach; incident X-ray spectrum; log-scale measurements; mass attenuation coefficient discretization; nonnegativity constraint; parsimonious measurement model parametrization; polychromatic X-ray computed tomography; scaling ambiguity; sparse signal reconstruction method; standard filtered backprojection; standard photon-energy discretization; unknown single material; Abstracts; Attenuation; Indexes; Beam hardening; computed tomography; signal reconstruction; x-ray tomography;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Acoustics, Speech and Signal Processing (ICASSP), 2013 IEEE International Conference on
Conference_Location :
Vancouver, BC
ISSN :
1520-6149
Type :
conf
DOI :
10.1109/ICASSP.2013.6637817
Filename :
6637817
Link To Document :
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