The shape and size of the projection of the focal spot of an x-ray tube largely depend on the direction of the beam, which results in a spatial difference of the point spread function (PSF) of the imaging system. A model developed for determining the PSF at an arbitrary point of the radiation field is presented in this article. The input data for the model are the geometric parameters of the system, the measured magnified projection of the effective focal spot, and the PSF in the internal structure of the detector. The difference in the width of the profiles of the PSF between the experimental and modeled data does not exceed 7.2%. The projection images are reconstructed by means of a deconvolution algorithm using the modeled PSF. The frequency–contrast characteristics of the images show improvement compared with the initial image.

中文翻译：

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确定数字射线照相系统点扩展函数的方法

X 射线管焦斑投影的形状和大小很大程度上取决于光束的方向，这会导致成像系统的点扩散函数 (PSF) 的空间差异。本文介绍了为确定辐射场任意点的 PSF 而开发的模型。模型的输入数据是系统的几何参数、有效焦斑的测量放大投影以及探测器内部结构中的 PSF。实验数据和模型数据之间 PSF 轮廓宽度的差异不超过 7.2%。投影图像是通过使用建模的 PSF 的反卷积算法重建的。与初始图像相比，图像的频率对比度特性有所改善。