Development of autofocusing system with video-rate camera for electron tomography

利用超高压电子显微镜层析成像技术观察医学和生物样品的三维结构是非常有用的。需要以样品的稍微不同的倾斜角度拍摄几十个或更多的图像，然而，机械旋转精度比几微米差。因此，我们完成了快速拍摄的倾斜图像系列与自动对焦和现场位置校正。采集分辨率为4000 × 4000像素的61幅CCD图像，在30分钟内完成，是传统方法的一半。

It is useful to observe the three-dimensional structure of medical and biological samples by using ultrahigh voltage electron microscope tomography. Taking several tens or more images with slightly different tilt angle of sample is necessary, however, a mechanical rotation accuracy is worse than of a few micrometers. Therefore, we accomplished fast taking of the tilt image series with automatic focusing and field position correction. To capture the 61 CCD images with a resolution of 4000 X 4000 pixels is completed in 30 minutes of half of conventional method.