数字射线成像空间分辨率的增强

Spatial Resolution Enhancement of Digital Radiography

成像空间分辨率是工业数字射线成像系统的重要技术指标,通过分析成像的物理过程,给出了成像过程的数学模型,进而得出影响数字射线成像空间分辨率的主要因素,并针对各种因素研究了相应的提高空间分辨率的方法。建立了成像系统的点扩展函数模型,给出了优化投影放大比的方法,提出了一种提高探测器采样频率和光电管采样孔径的硬件方法;采用了一种简便的方法抑制了散射对空间分辨率的影响;计算机模拟及实验结果验证了方法的有效性。

Imaging spatial resolution is the important qualification of industry X-ray DR（digital radiography） system. The mathematical model is described through analyzing the physical process of DR, and then the main factors which effect imaging spatial resolution are analyzed and presented according to the mathematical analysis and the physical analysis and the corresponding methods to improve the imaging spatial resolution are put forward. The PSF（point spread function） model is established, and the best magnification ratio of the projection is got according to this PSF model. One hardware method to improve the sampling frequency of flat-panel detector and the sampling aperture of photodiode is described, and the scatter is suppressed by one simple and convenient method. In the end, the feasibilities of the methods are validated by the experimental and computer simulation.