TRISO （tristructural-isotropic） fuel is a type of micro fuel particles used in high-temperature gas-cooled reactors （HTGRs）. Among the quality evaluation methods for such particles, inqine phase contrast imaging t...TRISO （tristructural-isotropic） fuel is a type of micro fuel particles used in high-temperature gas-cooled reactors （HTGRs）. Among the quality evaluation methods for such particles, inqine phase contrast imaging technique （PCI） is more feasible for nondestructive measurement. Due to imaging hardware limitations, high noise level is a distinct feature of PCI images, and as a result, the dimensional measurement accuracy of TRISO-coated fuel particles decreases. Therefore, we propose an improved denoising hybrid model named as NL P-M model which introduces non-local theory and retains the merits of the Perona-Malik （P-M） model. The improved model is applied to numerical simulation and practical PCI images. Quanti- tative analysis proves that this new anisotropic diffusion model can preserve edge or texture information effectively, while ruling out noise and distinctly decreasing staircasing artifacts. Especially during the process of coating layer thickness measurement, the NL P-M model makes it easy to obtain continuous contours without noisy points or fake contour segments, thus enhancing the measurement accuracy. To address calculation complexity, a graphic processing unit （GPU） is adopted to realize the acceleration of the NL P-M denoising.展开更多
根据菲涅耳衍射积分理论,提出了X射线光栅相衬成像系统的仿真模型。以聚甲基丙烯酸甲酯(PMMA)小球作为成像物体模型,选取30 ke V的X射线做模拟计算。通过仿真,得到了穿过球体和相位光栅的X射线波前的变化。采用多步位移法从模拟条纹图...根据菲涅耳衍射积分理论,提出了X射线光栅相衬成像系统的仿真模型。以聚甲基丙烯酸甲酯(PMMA)小球作为成像物体模型,选取30 ke V的X射线做模拟计算。通过仿真,得到了穿过球体和相位光栅的X射线波前的变化。采用多步位移法从模拟条纹图中恢复出了PMMA小球的相位信息,并分析了莫尔条纹对比度对成像质量的影响,为实际的实验提供可靠的参数选择。经过仿真得到的相移信息与通过实验得到一致,验证了仿真算法的正确性。展开更多
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grants 11275019,21106158 and 61077011in part by the National State Key Laboratory of Multiphase Complex Systems under Grant MPCS-2011-D-03+4 种基金in part by the National Key Technology R&D Program of China under Grant 2011 BAI02B02supported in part by the National Research Foundation of Korea(NRF)grantfunded by the Korean government(MEST)(No.2011-0020024)in part by the R&D program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korean government Ministry of Knowledge Economy(No.20101020300730)the Defense Acquisition Program Administration and the Agency for Defense Development for the financial support provided by both institutions
文摘TRISO （tristructural-isotropic） fuel is a type of micro fuel particles used in high-temperature gas-cooled reactors （HTGRs）. Among the quality evaluation methods for such particles, inqine phase contrast imaging technique （PCI） is more feasible for nondestructive measurement. Due to imaging hardware limitations, high noise level is a distinct feature of PCI images, and as a result, the dimensional measurement accuracy of TRISO-coated fuel particles decreases. Therefore, we propose an improved denoising hybrid model named as NL P-M model which introduces non-local theory and retains the merits of the Perona-Malik （P-M） model. The improved model is applied to numerical simulation and practical PCI images. Quanti- tative analysis proves that this new anisotropic diffusion model can preserve edge or texture information effectively, while ruling out noise and distinctly decreasing staircasing artifacts. Especially during the process of coating layer thickness measurement, the NL P-M model makes it easy to obtain continuous contours without noisy points or fake contour segments, thus enhancing the measurement accuracy. To address calculation complexity, a graphic processing unit （GPU） is adopted to realize the acceleration of the NL P-M denoising.
文摘根据菲涅耳衍射积分理论,提出了X射线光栅相衬成像系统的仿真模型。以聚甲基丙烯酸甲酯(PMMA)小球作为成像物体模型,选取30 ke V的X射线做模拟计算。通过仿真,得到了穿过球体和相位光栅的X射线波前的变化。采用多步位移法从模拟条纹图中恢复出了PMMA小球的相位信息,并分析了莫尔条纹对比度对成像质量的影响,为实际的实验提供可靠的参数选择。经过仿真得到的相移信息与通过实验得到一致,验证了仿真算法的正确性。
