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Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

2013

Computed tomography

Electrical and Computer Engineering Conference Papers, Posters and Presentations

Articles 1 - 2 of 2

Full-Text Articles in Biomedical Engineering and Bioengineering

Sparse X-Ray Ct Image Reconstruction And Blind Beam Hardening Correction Via Mass Attenuation Discretization, Renliang Gu, Aleksandar Dogandžić Dec 2013

Sparse X-Ray Ct Image Reconstruction And Blind Beam Hardening Correction Via Mass Attenuation Discretization, Renliang Gu, Aleksandar Dogandžić

Electrical and Computer Engineering Conference Papers, Posters and Presentations

We develop a nonlinear sparse X-ray computed tomography (CT) image reconstruction method that accounts for beam hardening effects due to polychromatic X-ray sources. We adopt the blind scenario where the material of the inspected object and the incident polychromatic source spectrum are unknown and apply mass attenuation discretization of the underlying integral expressions that model the noiseless measurements. Our reconstruction algorithm employs constrained minimization of a penalized least-squares cost function, where nonnegativity and maximum-energy constraints are imposed on incident spectrum parameters and negative-energy and smooth ℓ1-norm penalty terms are introduced to ensure the nonnegativity and sparsity of the density map ...


Beam Hardening Correction Via Mass Attenuation Discretization, Renliang Gu, Aleksandar Dogandžić Jan 2013

Beam Hardening Correction Via Mass Attenuation Discretization, Renliang Gu, Aleksandar Dogandžić

Electrical and Computer Engineering Conference Papers, Posters and Presentations

We develop a beam-hardening correction method for polychromatic xray 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 ...