Nesterets Yakov I, Gureyev Timur E
J Opt Soc Am A Opt Image Sci Vis. 2016 Apr 1;33(4):464-74. doi: 10.1364/JOSAA.33.000464.
The contrast-transfer-function (CTF) approximation, widely used in various phase-contrast imaging techniques, is revisited. CTF validity conditions are extended to a wide class of strongly absorbing and refracting objects, as well as to nonuniform partially coherent incident illumination. Partially coherent free-space propagators, describing amplitude and phase in-line contrast, are introduced and their properties are investigated. The present results are relevant to the design of imaging experiments with partially coherent sources, as well as to the analysis and interpretation of the corresponding images.
重新审视了广泛应用于各种相衬成像技术中的对比度传递函数（CTF）近似。CTF有效性条件扩展到了一大类强吸收和折射物体，以及非均匀部分相干入射照明情况。引入了描述幅度和相位同轴对比度的部分相干自由空间传播子，并研究了它们的性质。目前的结果与使用部分相干源的成像实验设计相关，也与相应图像的分析和解释有关。
