Research On Component Characterization Method Of Dual-energy CT Based On Reference Components

The material component characterization algorithm can understand the component distribution inside the material,which is of great significance to the study of the structure of the detected object and its physical and chemical properties.Because dual-energy CT introduces the information that the attenuation coefficient changes with energy,the composition of the material can be characterized under non-destructive conditions.However,in the conventional CT system,the X-ray energy is a continuous energy spectrum distribution,which makes the projection data and the reconstruction algorithm match The projection's single-energy hypothesis does not match,which leads to serious noise and hardening artifacts in the reconstructed image,which affects the accuracy of the component characterization results.Aiming at the noise problem,the common solution is to introduce a regular term to suppress the influence of noise on the component characterization results.However,in industrial CT applications,the detection object density is relatively high,so the hardening artifacts and noise levels are also high,so conventional images are removed.The noise method is not effective.Aiming at the problem of hardening artifacts and noise on the component characterization results,this paper is based on the conventional CT system,introduces the reference component as the prior information of the material,and explores the effect between the continuous energy spectrum X-ray and the known component.Relations,to study the component characterization methods of dual-energy CT.The thesis first analyzes the influence of the continuous X-ray energy spectrum on the CT reconstruction image.Aiming at the problem that the theoretical attenuation coefficient of the component cannot be obtained under the experimental conditions of the continuous energy spectrum,the X-ray equivalent energy is obtained by introducing the reconstruction result of the reference component high-purity phantom.Then,according to the relationship between the attenuation coefficient and energy,the theoretical attenuation coefficient of the component is obtained.In order to solve the influence of noise amplification,the Euclidean space is established based on the dual-energy reconstructed image,the Euclidean distance tolerance is obtained based on the reference component,and the neighboring pixels are combined as the neighborhood space based on the target pixel,and the target pixel is formed according to the neighborhood space.To suppress the problem of noise level amplification.There are differences in the size and material distribution between the reference component phantom and the detected object,resulting in inconsistent equivalent attenuation coefficients.Therefore,based on the reference component,the X-ray spectrum is estimated and the equivalent attenuation coefficient is corrected.Finally,experiments are carried out to verify the effectiveness of the method in this paper.The component characterization results show that the method in this paper has reference value for the component characterization of dual-energy CT in industrial applications.