基于平板探测器投影数据预处理的三维CT重构算法研究

大面积非晶硅平板探测器(flat panel detector-FPD)在工业透射射线成像领域得到越来越多的应用。基于FPD的圆轨道FDK型三维计算机层析成像技术(Computed Tomography,3D-CT)检测速度快,但成像质量不及2D-CT。为发挥3D-CT速度优势,抑制噪声同时提高图像重建的质量。以由平板探测器得到的二维投影数据为研究对象,提出了一种对投影数据分别进行高频和低频两次滤波的投影预处理方法,然后将分别重建的图像叠加最终得到高质量的重建图像。由算法的仿真实验结果表明,重建图像质量得到明显改善,系统噪声得到抑制。

Research on 3D-CT image reconstruction algorithm based on flat panel detector projection data pre-procession

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,and 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.The result of algorithm simulation showed the image quality improved and the system noise reduced apparently.