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

本文提出了一种新的高分辨率光学显微镜焦深扩展方法(1987-1988，发展科学研究助学金2)。这种焦深扩展技术实质上是基于Hausler方法(1972)，该方法对观察到的显微图像进行运动散焦平均和高通滤波。然而，本技术使用实时主动反卷积技术(由作者之一(1985)提出作为主动图像处理方法)，而不是在Hausler方法中使用传统的高通滤波器。本研究的主要目的是建立一个原型焦深扩展系统，并验证其实用性。在研究的第一阶段(1987)，利用压电驱动元件组装了一个快速的3D可移动样品台并将其安装在常规光学显微镜(奥林巴斯BHS)上。接下来，先前构建的活动图像处理系统(包括具有双极加权功能的帧积分器和个人计算机)已经通过接口电路连接到该样本台。在活动图像处理系统中还包括了使用液晶眼镜的立体观看子系统。利用该系统成功地对显微镜的透射式和反射式图像进行了焦深扩展和立体观察实验。对于N.A.=0.7的物镜，获得了约20微米的焦深扩展。焦深扩展也已在下一阶段(1988年)应用于位相显微镜。虽然位相显微镜的成像比较复杂，但通过使用类似的滤波函数，已经成功地实现了对位相物体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.