Study On Industrial CT Projection Data Preprocessing And Algebraic Reconstruction Algorithm

CT image reconstruction algorithm uses the projection data to reconstruct image, is the key technology of ICT detection. In the actual ICT system, due to the influence of mechanical error, etc, the actual center of rotation tends to be offset with the ideal center of rotation, thus makes trouble to the image reconstruction. In addition, the ring artifacts is also the main factor that affect the the quality of reconstruction image. Therefore, the preprocessing of projection data is necessary. This paper mainly studies the correction of center of rotation and ring artifacts, the main works are as follows:1. Researches the correction of the center of rotation in industrial CT reconstruction. On the basis of analyzing the existing center correction methods, proposes a modified geometry correction method, firstly uses the calibration template to find the offset of the center of rotation, and then through geometrical relationship pinpoint the exact center of rotation,finally, proves the feasibility and effectiveness of the method through the correction and reconstruction of solid rocket motor simulator projection data.2. Researches the ring artifact correction in industrial CT reconstruction. Firstly introduces briefly the origins, features and influence of the ring artifacts, analyzes and compares several existing ring artifact correction methods, and then presents a ring artifact correction method based on the cubic uniform B-spline fitting, finally, the experiments show that the proposed approach has good effect for the ring artifacts, and keeps the image details.3. Establishes the mathematical model of cone beam CT iterative reconstruction, introduces the reconstruction principle and reconstruction steps of ART reconstruction algorithm in detail,and on the basis of ART algorithm, studies SART and OS-SART algorithm, introduces the reconstruction steps of SART algorithm in detail, finally, according to the reconstructionresult, compares the advantages and disadvantages of three three iterative algorithms in detail through the reconstruction of the solid rocket engine and torque converter.