| 摘要 |
PURPOSE:To provide possibility of deciding the proper photographing time automatically by determining the time, which is required to obtain a proper image as the whole screen, and the time required to form the proper image in high-brightness regions by preliminary scanning, and by deciding the exposure time by reference to the smaller time of them. CONSTITUTION:First the view field for photographing is scanning preliminarily, and on the basis of the result therefrom a calculation control device 12 calculates the optimum exposure time T2 as the whole photo corresponding to one frame for the view field for photographing and the one-frame exposure time T1 to provide optimum photo image for the area where the counted value per unitary time maximizes. The smallest one of these times T1, T2 is selected as the optimum exposure time, and at a speed based thereon a scanning device 3 performs scanning, and thus photographing is conducted. This accomplishes automatic and quick scanning and photographing of a wide variety of specimens incl. a specimen with unknown density distribution. |
