Focal depth extension and stereo viewing apparatus for high resolution microscope based on active image processing method

本研究提出了一种利用主动图像处理技术实现高分辨率光学显微镜焦深扩展的新技术（1987 - 1988，发展科学研究资助项目2）。这种焦深扩展技术本质上是基于Hausler的方法（1972），其中移动离焦平均和高通滤波应用于观察到的显微图像。然而，目前的技术使用实时有源反褶积技术（由作者之一（1985）提出作为有源图像处理方法）代替Hausler方法中使用的传统高通滤波器。本研究的主要目的是构建一个原型震源深度扩展系统，并验证其实用性。在研究的第一阶段（1987年），使用压电驱动元件的快速3D可移动样品台已经组装并连接到传统光学显微镜（奥林巴斯BHS）上。接下来，通过接口电路将先前构建的主动图像处理系统（包括具有双极加权函数的帧积分器和个人计算机）连接到该采样平台。在主动图像处理系统中还包括一个使用液晶眼镜的立体视觉子系统。利用该系统，成功地对显微镜的透射和反射模式图像进行了焦深扩展和立体观测实验。对于N.A.= 0.7的物镜，得到了焦深扩展约20 μ m的离焦范围。下一阶段（1988年）也将焦点深度扩展应用于相显微镜。虽然相显微镜成像较为复杂，但利用类似的滤波功能，成功地实现了对相物的焦深扩展和立体观察。

A new technique of the focal depth extension for the high resolution optical microscope, with the aid of the active image processing method, has been proposed in the present study ( 1987 - 1988, Grant-in-Aid for Developmental Scientific Research 2 ).This focal depth extension technique is essentially based on Hausler's method ( 1972 )where moving defocus averaging and high pass filtering are applied to the observed microscopic image. The present technique, however, uses real time active deconvolution technique ( proposed by one of the authors ( 1985 ) as the active image processing method ) instead of the conventional high pass filter used in the Hausler's method. Main aims of this study are to construct a prototype focal depth extension system and to confirm its practicability.At the first stage of the study ( 1987 ), a fast 3D movable sample stage using piezo driving elements has been assembled and attached to the conventional optical microscope ( Olympus BHS ). Next, the previously constructed active image processing system ( include a frame integrator with bipolar weighting function and a personal computer ) has been connected to this sample stage via interface circuits. A stereo viewing subsystem using liquid crystal glasses has been also included in the active image processing system. By using this system, focal depth extension and stereo viewing experiments have been successfully achieved to transmission and reflection mode images of the microscope. Focal depth extension about 20 um defocus range has been obtained for the objective lens of N.A.= 0.7. Focal depth extension has been also applied to the phase microscope at the next stage ( 1988 ). Although the image formation of the phase microscope is some more complicated, successful focal depth extension and stereo viewing have been achieved with phase object by using a similar filtering function.