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为提高工业CT中的图像质量,提出了一种校正X射线多色性产生的硬化现象的方法。该方法利用多色系统参数,将多色投影数据通过多项式运算转化为单色投影数据。定义了多色系统参数,证明了该参数在中能量段(0.3～5.0MeV),中低原子序数物质条件下,近似与被扫描物体无关的性质,并给出了获得该参数的方法。用该方法对模拟截面进行了硬化校正数字模拟实验。校正结果和真实值符合的很好。与现有的硬化校正方法相比,该方法不需进行迭代,不需要准确的先验知识,校正速度快和应用灵活是其主要优势。
In order to improve the image quality in industrial CT, a method of correcting the hardening phenomenon caused by X-ray polychromaticity is proposed. The method utilizes the multi-color system parameters to transform the multi-color projection data into monochromatic projection data through polynomial operation. The multi-color system parameters are defined. It is proved that this parameter approximates the properties unrelated to the object to be scanned under medium energy (0.3-5.0 MeV) and medium-low atomic number materials, and the method of obtaining this parameter is given. Simulated cross-sections were hardened with this method. The calibration result is in good agreement with the real value. Compared with the existing hardening correction method, this method does not need to iterate, does not need accurate a priori knowledge, fast correction and flexible application are its main advantages.