Automatic Beam Hardening Correction For CT Reconstruction

In computed tomography (CT) the quality of reconstructed images depends on several reasons: the quality of the set-up calibration; precision of the mathematical model, used in the reconstruction procedure; the reconstruction technique used; quality of the numerical implementation of the reconstruction algorithm. Most of fast reconstruction algorithms use the X-ray monochromaticity assumption. If we apply the algorithms to reconstruct the images from the projections measured in polychromatic mode then the reconstructed images will be corrupted by so-called cupping artifacts due to beam hardening. There are several approaches to take into account polichromaticity. One of them is to correct the sinograms before reconstruction. This paper presents the usage of Radon invariant to estimate the gamma parameter in the procedure of the sinogram correction for beam hardening (BH).