X-ray Energy Spectrum Recovery And Beam Hardening, Scattering Studies

Images reconstructed from polychromatic X-ray contain the "rings and cup " fakes which seriously affect the quality of the reconstructed images. The research of beam-hardening correction is of great meaning.Most current correction algorithms have to assume that the X-ray beam spectra and the mass attenuation coefficients of the detected object related to different energy are given. However, the beam spectrum of the CT system isn't normally constant. It is necessary to design an algorithm to estimate the X-ray spectrum.In this paper, we present a method for estimating the X-ray spectrum of industrial CT system. We have designed a "wedge-phantoms" which is composed of iron to study the X-ray spectrum. Then, we have designed the algorithm mainly using Newton method to overcome ill condition of the model. Numerical simulations were conducted to validate the proposed algorithm.An iteration algorithm is applied to eliminate beam hardening on the assumption that the spectrum of X-ray source is known. And our iteration algorithm is capable of eliminating beam hardening artifacts in case of the composition and attenuation of scanned object is known. Experimental results show that this algorithm is accurate. More over, we design an experiment in order to analyze the proportion and effect of scattering phenomenon, which will lead to improve the quality of reconstructed images.