Research On CT Imaging Method Of Complex Profiled Workpiece Based On Contour Prior

X-ray CT inspection technology is one of the main research techniques to realize internal defect detection and geometric characteristic measurement of objects.In the X-ray CT imaging inspection system,complex shaped workpieces have complicated structures and serious scattering phenomena,and at some projection angles,because of the large effective thickness in the ray transillumination direction,insufficient radiation dose penetration,the projection data quality will be poor.The quality of the reconstructed image obtained by the traditional CT reconstruction algorithm is low,the edges of workpieces reconstruction images are blurred,and the complete contour information of the workpiece cannot be obtained.The regularization reconstruction algorithm based on a priori information can reconstruct a higher quality image under the condition of poor projection quality by adding a priori constraint conditions.Therefore,in this paper,aiming at the problem of missing edges in the CT reconstruction results of complex shaped workpieces,a CT reconstruction algorithm based on contour prior constraints is studied.First,the SART-TV reconstruction algorithm based on contour prior constraints is studied.Based on the principle of stereo vision imaging,the monocular multi-view 3D reconstruction technology is used to obtain the surface contour information of complex structural parts,and the prior image registration is completed according to the spatial position relationship between the monocular coordinate system and the CT coordinate system,and the contour image as the prior information is coupled to the CT reconstruction process.The feasibility and effectiveness of the method are verified through actual data experiments.Secondly,to solve the internal details of the reconstructed image for the problem of not recovering well,the contour-constrained CT reconstruction algorithm based on the wavelet compact frame is studied.By regularizing the wavelet compact frame transform coefficients of the reconstructed image,combined with the high-frequency and low-frequency information of the prior image of the contour boundary,and then the alternating direction method is used to efficiently solve the model.Experimental results prove that the method in this paper can effectively suppress artifacts and noise,and retain the edge and internal details of the reconstructed image.Compared with the traditional iterative reconstruction method,this method can better reconstruct the contour information of the workpiece,which is beneficial to improve the complexity of the workpiece Imaging accuracy.