| 摘要 |
PURPOSE:To enable an electron microscope to be accurately focused without relaying on macroscopic observation by storing two images recoded before and after the change in the incidence angle of electron rays in different image memories and obtaining intensity comparison for each picture element corresponding to the similarity between the two images by line operation. CONSTITUTION:Those images produced before and after the change of the incidence angle of electron rays or those images produced before and after the deflection of incident electron rays are stored in image memories 16 and 17 through an A/D converter 14 and change-over switch 15 respectively. A signal F indicating whether the contents of these two memories are the same or not is produced from a computing element 18. The signal F is delivered into a meter 25 or a microcomputer 26 through a D/A converter 24, thereby indicating whether the electron microscope is focused or not. Accordingly, image changes can be highly accurately evaluated without relying on macroscopic observation. |
