|
The algorithm for 3D vector image reconstruction from a set of spectral tomographic projections collected with CT set-up completed with an optical element or elements inside the optical path behind the sample is proposed. The purpose of their placement into the optical path is to divide the integral polychromatic projection into a series of monochromatic projections, i.e., to get a multi-channel image. Understanding of the reconstruction results in the monochromatic case is beyond question, the relationship between the reconstructed spatial distribution of the linear attenuation coefficient and the discrete description of the elemental structure of the probed object is linear. In difference with monochromatic case the result of the reconstruction from polychromatic projections is a spatial distribution of the so-called effective or average attenuation coefficient, its connection to a discrete description of the elemental structure is nontrivial. However, if the distribution of the averaged coefficient is supplemented by distributions of linear coefficients for several energies, then it is possible to estimate of the local composition of the object. We present a model for the formation of spectral multi-channel projection based on crystal analyzer usage and describe the steps needed to solve the tomography inverse problem.
|
