Three-dimensional hard X-ray imaging using coded penumbral camera

近年来，利用超短高强度激光脉冲进行激光聚变和激光与物质相互作用的研究得到了广泛的关注。硬x射线成像（大于10keV）是超短高强度激光脉冲等离子体诊断的一个重要问题。迄今为止，半影成像已被证明是一种强大的穿透辐射成像技术，如硬x射线和中子。半影成像的局限性在于对半影图像中的噪声比较敏感，并且不具有层析分辨率。为了克服上述局限性，我们提出了一种启发式鲁棒重建方法和一种基于m序列的编码半影成像技术。利用编码半影孔径可以获得高SN比和层析分辨率的编码半影图像。主要研究结果如下：(1)提出了一种启发式重建方法，该方法对半影图像具有较强的胸围和容忍度。该方法已用于测量激光产生的等离子体密度。研究结果发表在《科学》杂志上。Instrum。(2)我们提出了一种启发式盲重建方法。现在可以仅从半影图像重建源图像。该方法已应用于实际的激光聚变实验。研究结果发表在《科学》杂志上。Instrum。(3)我们提出了一种启发式方法，用于从三个针孔图像重建三维图像。该方法已应用于实际的激光聚变实验。研究结果发表在《科学》杂志上。Instrum。(4)我们提出了一种基于m序列的编码半影成像技术。利用编码半影孔径可以获得高SN比和层析分辨率的编码半影图像。结果将提交给Rev. Sci。Instrum。(5)定量估计了m序列的层析分辨率，表明精细采样可以提高层析分辨率。研究结果发表在《科学》杂志上。Instrum。(6)我们提出了一种基于模拟退火（SA）的启发式算法，用于编码孔径图像的三维图像重建。实验结果表明，该方法能显著提高重建层析图像的质量。针对启发式算法计算量大的问题，提出了一种快速算法。少

Recently, many researches have been focused on laser fusions and laser-matter interactions using ultra-short high intensity laser pulse. Imaging of hard x-ray (higher than 10keV) is an important issue for diagnostics of the plasma generated by the ultra-short high intensity laser pulse. To date, the penumbral imaging has been demonstrated as a powerful technique for imaging of penetrating radiations such as hard x-ray and neutrons. Limitations of the penumbral imaging are that it is sensitive to the noise contained in the penumbral images and it do not have any tomographic resolutions.In order to overcome above limitations, we proposed a heuristic method for robust reconstruction and a coded penumbral imaging technique based on a m-sequence. It is possible to obtain a coded penumbral image with high SN ratio and tomographic resolution by the use of coded penumbral apertures. The main results are summarized as following:(1) We proposed a heuristic reconstruction method, which is very ro … More bust and tolerant to the noise contained in the penumbral images. The method has been applied for measurements of laser-produced plasma density. The results have been published in Rev. Sci. Instrum. (Ref. 4).(2) We proposed a heuristic blind reconstruction method. It is now possible to reconstruct the source image from the penumbral images alone. The proposed method has also been applied to real laser fusion experiments. The results have published in Rev. Sci. Instrum. (Ref. 3).(3) We proposed a heuristic method for 3D image reconstructions from three pinhole images. The proposed method has also been applied to real laser fusion experiments. The results have been published in Rev. Sci. Instrum. (Ref. 1).(4) We newly proposed a coded penumbral imaging technique based on m-sequence. It is possible to obtain a coded penumbral image with high SN ratio and tomographic resolution by the use of coded penumbral apertures. The results will be submitted to Rev. Sci. Instrum.(5) We quantitatively estimated the tomographic resolution of m-sequence and shown that the tomographic resolution can be improved by use of the fine sampling. The results have published in Rev. Sci. Instrum. (Ref. 2).(6) We proposed a new heuristic algorithm for three-dimensional image reconstruction from coded aperture images based on simulated annealing (SA). It has been shown that the reconstructed tomographic images can be significantly improved by using the proposed method. We also proposed a fast algorithm to reduce the large computation cost of the heuristic algorithm. Less