Research On The Algorithm Of Segmental Multi-energy CT Scanning Imaging

X-ray CT imaging technology is one of the important methods in industrial non-destructive testing,public safety inspection and medical diagnosis.However,with the rapid development of science and technology,traditional single-energy CT imaging technology for structural analysis can‘t meet a high requirement of material contrast in the current industrial CT.In the current CT systems,X-ray spectrum is continuous with different energy segments which are produced by X-ray source,and the attenuation coefficient of object is varied with the X-ray energy.But the current reconstruction algorithm is based on the assumption: X-ray is single ray.The inconsistency of X-ray source and reconstruction algorithm is easy to result a phenomenon of hardening artifacts and metal artifacts,and make the CT reconstruction poor.Therefore,domestic and foreign researchers have explored the multi-function CT reconstruction algorithm for dual-energy CT system and photon counting detector.Due to the high cost,the two systems have some limitations in the practical engineering application.In order to realize the purpose of multi-function CT imaging on the basis of the traditional CT system,this paper studies the imaging method of a Segmental Multi-energy CT in view of the basic mathematical principle of imaging of dual energy CT system.Firstly,this paper puts forward the theory and method of Segmental Multi-energy CT imaging on the study of CT imaging principle.Based on the idea of simulation design,a sub-segment CT model of dual energy and multi-energy is obtained.By analyzing the characteristics of the sub-segment projection data and the contrast of the reconstructed images in the simulation results,the validity of the model and the significance of the theory and method of CT are tested.Based on the accurate location of high frequency of wavelet analysis,the gray-step of segmental multi-energy projection is corrected by the gray-step height of low frequency,and is reconstructed to realize segmental multi-energy CT imaging.The simulation experimentindicated that the method increased the energy spectrum information and eliminated the gray-step artifact.Finally,based on the E-ART dual-energy CT reconstruction algorithm,a multi-functional iterative reconstruction algorithm of Segmental Multi-energy CT scanning is proposed.Simulation experiments show that segmented CT imaging can not only eliminate reconstructed image artifacts,but also realize the distinction of internal material.Thus,the quality of the reconstructed image is improved.