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

这项研究的第一个目的是发展实用的基于焦深扩展暗场显微镜的像差校正技术，既适用于光学显微镜，也适用于电子显微镜。第二个目标是对观测图像进行非线性成像现象的理论分析，根据这些目标，在第一阶段(2001)发展了包含非线性成像效应的广义成像理论，这是三维成像理论的扩展。在此理论基础上，编制了评价无像差观测的图像仿真程序。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制造。在下一阶段(2002)的研究中，首先研究了在焦深扩展暗视野显微镜的基础上对无像差观察的评价。结果表明，即使对于暗场图像，只要采用动态中空锥体照明和适当的图像处理，也可以实现幅相分量的分离。用该显微镜对暗场像进行了评价，结果表明球差的影响是很容易校正的。然而，对于散焦来说，幅度和相位分量的分离是非常困难和严重的。在实际应用中，它可能只适用于严格聚焦环境下的非常薄的样品。最后，本发明的无像差焦深扩展暗场显微镜技术可适用于荧光显微镜和自发辐射显微镜等具有相似三维成像特性的显微镜。

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.