编码源中子成像的可见光模拟

Simulation of coded neutron source imaging by visible light

采用编码源能大大提高中子成像的中子注量率,同时保持较高的准直比。对改进的均匀冗余矩阵编码源中子成像进行了计算机模拟并利用可见光进行了实验,初步验证了编码源中子成像的可行性,并且探索了各种在非理想条件下成像对图像质量的影响并提出了解决方法。结果表明,编码源配合相关算法能够较好地重建图像,反解后的物体尺寸及分辨能力与单孔成像相当,同时缩短了曝光时间。若物体与理想成像面存在着位置或旋转偏差,则投影大小与探测器CCD像素、解码矩阵尺寸便不能对齐,但仍可以通过对图像背景噪声标准差的计算来后期修正图像,也可以利用此方法在实验前确定编码源成像系统中理想成像面的位置,以确保图像质量。

The coded source can increase the neutron flux while keep good beam collimation in neutron imaging.A computer simulation method for modified uniformly redundant arrays coded neutron source imaging was established and the optical experiments were carried out subsequently.The results indicate that the image can be reconstructed well by the correlation algorithm in coded source imaging.The dimension and resolution of the reconstructed objects are similar with those acquired by single pinhole,and the exposure time is shortened greatly.The impact of non-ideal conditions on image quality was also explored.If the object is placed in a position with magnifying and rotating deviations from ideal conditions,the projection can not match the CCD pixels of the detector and the decoding array,which will cause artifacts in the reconstructed image.The artifacts can be corrected with the parameters derived from the standard deviation curve of background noise.This method based on the standard deviation curve can also help to find out the ideal imaging position before formal coded source imaging experiments,ensuring the quality of the reconstructed image.