中子半影成像的计算机断层重建技术

Computed Tomography Reconstruction Technology for Neutron Penumbral Imaging

实际用于中子半影成像重建的方法都是线性方法,而计算机断层重建是一种能够用于中子半影成像重建的新方法。介绍了中子半影成像的断层重建原理,将半影成像的诊断图像沿径向等角度提取、微分后就可以使用断层重建方法重建。给出了使用卷积反投影方法重建不同噪声诊断图像的结果,并分析了断层重建的优缺点。重建结果表明,断层重建方法能够重建出源分布,且诊断图像的信噪比越高,重建效果越好。断层重建方法不需全仿真模拟系统点扩展函数,能够自动挑选探测图像有用的半影区数据,删除探测图像中无用的亮区和本底区数据,避免了无用数据的强干扰。

The useful reconstruction technologies for neutron penumbral imaging are all linear method, and computed tomography （CT） is one of linear methods. The principle of the CT reconstruction for neutron penumbral imaging is introduced, and the detecting image with penumbral imaging, which is extracted and differentiated along radial direction, can be reconstructed by the CT method. The detecting imaging with different noises is decoded by convoluted backprojection method, and the advantages and disadvantages of the CT reconstruction are analyzed. According to the results, the source distribution can be reconstructed by the CT method, and the higher the signal-to- noise ratio of the detecting imaging is, the better reconstruction result is. The point spread function doesn＇t needs to be fully simulated before decoding, and the results will not be interfered by the useless data, because the useful data can be automatically picked from the penumbral region, and the useless data will be deleted in the bright and dark regions.