Beam hardening correction method forturbine blades CT imaging

Because of beam hardening, images from a polychromatic industrial X-ray computed tomography (ICT) system are led to cupping and streak artifacts, when turbine blades are tested. In conventional polynomial fitting correction technique, it needs stepladder phantom to establish the beam hardening correction model, so it affects the practicability of this technique. To overcome this affect, a beam hardening correction method using polynomial fit based on reprojection was researched The method segmented the original CT image into different sections and reprojected the image to obtain the thickness set of X-ray penetrating specimen, fitted the relationship between the thickness and the polychromatic projection data by polynomial to establish the beam gardening correction model to calibrate the raw projection data. Research shows this method can eliminate beam hardening effectively and CT imaging quality is conspicuously improved, especially for the key cross-sections of turbine blades.