投影数据预处理三维CT重构算法研究

Research on 3D-CT Image Reconstruction Algorithm Based on Wavelet Multiscale Decomposition FPD Projection Data Pre-Procession

大面积非晶硅平板探测器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(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进行小波分解,分别对高频和低频进行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。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。

Large-area a-Si X-ray fiat 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 3D-CT and improve the quality of the reconstructed image, at the same time reduce the noise, the research object is 2D projection data from FPD, projection pre-procession method that the projection data was filtered twice in high-frequency and low-frequency respectively with wavelet muhiscale decomposition were proposed, then the two reconstructed images were added to make the high quality reconstructed image. The result of algorithm simulation shows the image quality is improved and the system noise is reduced apparently.