%AGu, Renliang%ADogandzic, Aleksandar%BJournal Name: AIP conference proceedings; Journal Volume: 34 1650
%D2015%I
%JJournal Name: AIP conference proceedings; Journal Volume: 34 1650
%K
%MOSTI ID: 10012984
%PMedium: X
%TPolychromatic sparse image reconstruction and mass attenuation spectrum estimation via B-spline basis function expansion
%XWe develop a sparse image reconstruction method for polychromatic tomography (CT) measurements under the blind scenario where the material of the inspected object and the incident energy spectrum are unknown. To obtain a parsimonious measurement model parameterization, we first rewrite the measurement equation using our mass attenuation parameterization, which has the Laplace integral form. The unknown mass-attenuation spectrum is expanded into basis functions using a B-spline basis of order one. We develop a block coordinate-descent algorithm for constrained minimization of a penalized negative log-likelihood function, where constraints and penalty terms ensure nonnegativity of the spline coefficients and sparsity of the density map image in the wavelet domain. This algorithm alternates between a Nesterovâ€™s proximal-gradient step for estimating the density map image and an active-set step for estimating the incident spectrum parameters. Numerical simulations demonstrate the performance of the proposed scheme.
%0Journal Article