射线平板探测器成像系统的数理模型

非晶硅X射线数字平板探测器是目前唯一可取代胶片照相的新型技术,对其成像特性的研究已成为高像质的DR和三维CT检测技术的基础。目前X射线成像系统均是以线性时不变理论作为分析基础的。基于X射线平板探测器成像系统、成像机理和几何参数建立了成像系统的点扩展函数(PSF)。用圆柱体等效二维PSF模型,使成像系统退化为比例系统,从而把复杂的反卷积运算转化成用代数方程来求解,能够快速实现通过探测器输出图像来估计透照工件的二维输入图像。此模型的建立为在实际检测中利用输出的图像通过线性变换得到输入估计。在DR系统中,基于上述数理模型建立了灵敏度模型,利用输出场强可以很好的再现输入场强。

Mathematical model based on X-ray imaging system of flat panel detector

The linearity time_invariant theory was based on analyze the X_ray imaging system. So it was the impotent to analyze the point spread function (PSF). Based on the photo_electricity conversion process and imaging mechanism and geometry parameter of X_ray flat_panel detector imaging system, the point spread function model of imaging system was obtained. The cylinder equivalented Gaussian function as the PSF of imaging system, so the complex deconvolution operation was replaced with algebraic equation.The workpiece radiography was gotten from the output image of the system. The model becomes the mathematical foundation that the output image estimates input image using linearity_invariant in practice testing. In the laboratory's DR system, based on the mathematical function, the sensitive model is obtained, so the input field intensity is effective recovery using output field intensity.