Three-dimensional Ct Reconstruction Algorithm Based On Flat-panel Imaging Device And Applied Research

Large-area a- Si X- ray flat panel detector (FPD) is becoming more and more popular in the field of industry transmission radiation imaging. FDK- type three dimensional computed tomography (3D-CT) with circular orbit based on FPD can execute inspection rapidly , but its imaging quality can not reach that of 2D-CT. In order to make the best of the speed advantage of 3DCT and improve the quality of the reconstructed image, at the same time reduce the noise. The research object of this paper is 2D projection data from FPD, we propose projection pre-procession method that the projection data was filtered twice in high-frequency and low-frequency respectively, then add the two reconstructed images to make the high quality reconstructed image. Based this method we induct the image wavelet multi-scale decomposition theory, we propose new method. Firstly wavelet decompose the projection, secondly the projection data was also filtered twice in high-frequency and low-frequency respectively, thirdly after wavelet composing the projection data, add the two reconstructed images to make the final high quality reconstructed image. The result of algorithm simulation showed the image quality improved and the system noise reduced apparently.For the low reconstructed exactness of approximately FDK ( Feldkamp, Davis and Kress) algorithm, and how to arrange scan orbit in order to satisfies the Data Sufficient Condition to obtain the complete information in Radon domain, we discuss a novel two-orthogonal-circle orbit implication in ICT, with the same system complexity, bring up corresponding improved FDK algorithm , obtain the sufficient data, improve the reconstruction exactness.