The study aims to develop a rational polynomial approximation method for improving the accuracy of the effective atomic number calculation with a dual-energy X-ray imaging system. This method is based on a multi-materials calibration model with iterative optimization, which can improve the calculation accuracy of the effective atomic number by adding a rational term without increasing the computation time. The performance of the proposed rational polynomial approximation method is demonstrated and validated by both simulated and experimental studies. The twelve reference materials are used to establish the effective atomic number calibration model, and the value of the effective atomic numbers are between 5.444 and 22. For the accuracy of the effective atomic number calculation, the relative differences between calculated and experimental values are less than 8.5%for all sample cases in this study. The average calculation accuracy of the method proposed in this study can be improved by about 40%compared with the conventional polynomial approximation method. Additionally, experimental quality assurance phantom imaging result indicates that the proposed method is compliant with the international baggage inspection standards for detecting the explosives. Moreover, the experimental imaging results reveal that the difference of color between explosives and the surrounding materials is in significant contrast for the dual-energy image with the proposed method.

中文翻译：

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使用双能 X 射线成像系统的有理多项式近似法计算有效原子序数

该研究旨在开发一种有理多项式近似方法，以提高双能 X 射线成像系统有效原子序数计算的准确性。该方法基于迭代优化的多材料标定模型，通过添加有理项提高有效原子序数的计算精度，且不增加计算时间。模拟和实验研究证明并验证了所提出的有理多项式近似方法的性能。使用十二种标准物质建立有效原子序数校准模型，有效原子序数值在5.444~22之间。为了有效原子序数计算的准确性，本研究中所有样本的计算值与实验值之间的相对差异均小于 8.5%。与传统的多项式逼近方法相比，本研究提出的方法的平均计算精度可提高约40%。此外，实验质量保证体模成像结果表明所提出的方法符合国际行李检查标准，用于检测爆炸物。此外，实验成像结果表明，爆炸物与周围材料之间的颜色差异与所提出方法的双能图像形成显着对比。与传统的多项式逼近方法相比，本研究提出的方法的平均计算精度可提高约40%。此外，实验质量保证体模成像结果表明所提出的方法符合国际行李检查标准，用于检测爆炸物。此外，实验成像结果表明，爆炸物与周围材料之间的颜色差异与所提出方法的双能图像形成显着对比。与传统的多项式逼近方法相比，本研究提出的方法的平均计算精度可提高约40%。此外，实验质量保证体模成像结果表明所提出的方法符合国际行李检查标准，用于检测爆炸物。此外，实验成像结果表明，爆炸物与周围材料之间的颜色差异与所提出方法的双能图像形成显着对比。