Abstract：
UNASSIGNED: The polychromatic X-rays generated by a linear accelerator (Linac) often result in noticeable hardening artifacts in images, posing a significant challenge to accurate defect identification. To address this issue, a simple yet effective approach is to introduce filters at the radiation source outlet. However, current methods are often empirical, lacking scientifically sound metrics.
UNASSIGNED: This study introduces an innovative filter design method that optimizes filter performance by balancing the impact of ray intensity and energy on image quality.
UNASSIGNED: Firstly, different spectra under various materials and thicknesses of filters were obtained using GEometry ANd Tracking (Geant4) simulation. Subsequently, these spectra and their corresponding incident photon counts were used as input sources to generate different reconstructed images. By comprehensively comparing the intensity differences and noise in images of defective and non-defective regions, along with considering hardening indicators, the optimal filter was determined.
UNASSIGNED: The optimized filter was applied to a Linac-based X-ray computed tomography (CT) detection system designed for identifying defects in graphite materials within high-temperature gas-cooled reactor (HTR), with defect dimensions of 2 mm. After adding the filter, the hardening effect reduced by 22%, and the Defect Contrast Index (DCI) reached 3.226.
UNASSIGNED: The filter designed based on the parameters of Average Difference (AD) and Defect Contrast Index (DCI) can effectively improve the quality of defect images.
UNASSIGNED: This study introduces an innovative filter design method that optimizes filter performance by balancing the impact of ray intensity and energy on image quality.
UNASSIGNED: Firstly, different spectra under various materials and thicknesses of filters were obtained using GEometry ANd Tracking (Geant4) simulation. Subsequently, these spectra and their corresponding incident photon counts were used as input sources to generate different reconstructed images. By comprehensively comparing the intensity differences and noise in images of defective and non-defective regions, along with considering hardening indicators, the optimal filter was determined.
UNASSIGNED: The optimized filter was applied to a Linac-based X-ray computed tomography (CT) detection system designed for identifying defects in graphite materials within high-temperature gas-cooled reactor (HTR), with defect dimensions of 2 mm. After adding the filter, the hardening effect reduced by 22%, and the Defect Contrast Index (DCI) reached 3.226.
UNASSIGNED: The filter designed based on the parameters of Average Difference (AD) and Defect Contrast Index (DCI) can effectively improve the quality of defect images.
摘要：
■由线性加速器（直线加速器）产生的多色X射线通常会导致图像中明显的硬化伪影，对准确的缺陷识别提出了重大挑战。为了解决这个问题，一个简单而有效的方法是在辐射源出口引入过滤器。然而,当前的方法通常是经验性的，缺乏科学合理的衡量标准。
■本研究介绍了一种创新的滤波器设计方法，该方法通过平衡射线强度和能量对图像质量的影响来优化滤波器性能。
■首先，使用GEometryANd跟踪（Geant4）模拟获得了各种材料和过滤器厚度下的不同光谱。随后，这些光谱及其相应的入射光子计数被用作输入源，以生成不同的重建图像。通过综合比较有缺陷区域和无缺陷区域图像中的强度差异和噪声，在考虑硬化指标的同时，确定了最佳滤波器。
■优化的滤波器应用于基于直线加速器的X射线计算机断层扫描（CT）检测系统，该系统旨在识别高温气冷反应堆（HTR）内石墨材料的缺陷，2毫米的缺陷尺寸。添加过滤器后，硬化效果降低了22%，缺陷对比指数(DCI)达到3.226。
■基于平均差分（AD）和缺陷对比指数（DCI）的参数设计的滤波器可以有效提高缺陷图像的质量。
■本研究介绍了一种创新的滤波器设计方法，该方法通过平衡射线强度和能量对图像质量的影响来优化滤波器性能。
■首先，使用GEometryANd跟踪（Geant4）模拟获得了各种材料和过滤器厚度下的不同光谱。随后，这些光谱及其相应的入射光子计数被用作输入源，以生成不同的重建图像。通过综合比较有缺陷区域和无缺陷区域图像中的强度差异和噪声，在考虑硬化指标的同时，确定了最佳滤波器。
■优化的滤波器应用于基于直线加速器的X射线计算机断层扫描（CT）检测系统，该系统旨在识别高温气冷反应堆（HTR）内石墨材料的缺陷，2毫米的缺陷尺寸。添加过滤器后，硬化效果降低了22%，缺陷对比指数(DCI)达到3.226。
■基于平均差分（AD）和缺陷对比指数（DCI）的参数设计的滤波器可以有效提高缺陷图像的质量。
