CT system beam hardening elimination method and CT system beam hardening elimination system based on sonogram

Abstract

The invention relates to a CT system beam hardening elimination method based on a sonogram. The method comprises the following steps of obtaining CT projection image data; removing a scan object from a check platform of a CT machine for scanning to obtain CT bright field image data and calculating average bright field image data of the CT bright field image data; scanning to obtain CT dark field image data and calculating average dark field image data of the CT dark field image data; performing preprocessing and coordination transformation on the CT projection image data to obtain a projection data sonogram and performing filtering processing and correction on the sonogram; rebuilding a CT image based on the corrected projection data sonogram. According to the CT system beam hardening elimination method and a CT system beam hardening elimination system based on the sonogram, a series of processing is performed on the CT projection image data before rebuilding the CT image, so that the goodness of fit between the CT projection image data and the actual image data is improved, therefore the beam hardening can be precisely eliminated.

Description

technical field [0001] The invention relates to the technical field of CT, in particular to a sinogram-based CT system beam hardening elimination method and system thereof. Background technique [0002] Beam hardening is caused by the pluripotency of the X-ray beam energy spectrum and the dependence of the attenuation coefficient on energy. When multi-energy X-rays pass through an object, X-rays with lower energy are preferentially absorbed due to the photoelectric effect, which increases the proportion of high-energy components of X-rays penetrating the material, which is manifested as an increase in the average energy of X-rays, so that X-rays penetrate The increase of the length has a stronger penetration ability, and the peak of the spectrum distribution moves to the higher energy direction, which is the beam hardening effect. It will cause the measured object slices with uniform density to have different brightness on the reconstructed CT image, and the gray value dist...

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Problems solved by technology

However, because the correction procedure of this method is too simple, it is impossible to eliminate the beam hardening accurately

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