Study on aberration-free focal-depth-extended dark-field microscopy and non-linear imaging analysis

本研究的第一个目的是发展实用的像差校正技术的基础上焦深扩展暗场显微镜，适用于光学和电子显微镜。第二个目标是对非线性成像现象进行理论分析，对观测到的图像进行解释，第一阶段（2001年）发展了包含非线性成像效应的广义成像理论，它是三维成像理论的扩展。在此理论基础上，编制了无像差观测评价的图像仿真程序。在第一阶段中，同时进行了无像差焦深扩展暗场显微镜的设计和构造。此外，还制作了所需的附加控制硬件和处理程序，并将其包含在现有的显微镜系统中。在下一阶段（2002年）的研究中，首先对基于焦深扩展暗场显微镜的无像差观察的评价进行了研究。结果表明，即使对于暗场图像，通过使用动态空心锥照明和适当的图像处理，振幅和相位分量的分离也是可能的。从使用本显微镜的暗场图像的评价，得出的结论是，球面像差的影响是容易校正的。然而，对于散焦，幅度和相位分量的分离是非常困难和严重的。在实践中，它可能只适用于非常薄的样品下，严重的焦点设置。最后，用于无像差焦深扩展暗场显微镜的本技术可以适用于具有类似3D成像特性的显微镜，诸如荧光和自发射显微镜。

The first aim of this study is the development of practical aberration correction techniques based on the focal-depth-extended dark-field microscopy, applicable to both optical and electron microscopes. And also, the theoretical analysis on non-linear imaging phenomena is the second aim, to interpret observed images.According to these aims, the generalized imaging theory including non-linear imaging effects, is developed in the first stage (2001), which is the extension of the three dimensional (3D) imaging theory. Under the basis of this theory, image simulation programs to evaluate the aberration-free observation were then coded. The design and construction of an aberration-free focal-depth-extended dark-field microscope were simultaneously carried out in this first stage. In addition, required additional control hardware and processing programs were also made and these were included in the present microscope system.In the next stage (2002) of the study, the evaluation of the aberration free observation under the bases of the focal-depth-extended dark-field microscopy was first examined. Results show that the separation of amplitude and phase components is possible even for dark-field images by the use of the dynamic hollow-cone illumination and the proper image processing. From the evaluation for dark-field images using the present microscope, it is concluded that the effect of the spherical aberration is easily corrected. The separation of the amplitude and the phase components is, however, very difficult and severe for the defocus. In practice, it may be applicable for only very thin samples under the severe focus setting. Finally, the present techniques for the aberration-free focal-depth-extended dark-field microscope can be applicable to microscopes such as fluorescent and self-emission microscopes possess similar 3D imaging characteristics.