| 摘要 |
PURPOSE:To normally obtain an excellent reproducing picture, by a method wherein a maximum and a minimum luminance are set within an input sensitivity range of a photographing tube through compression of a luminance distribution of a transmitting information of an object to be measured converted into an optical image. CONSTITUTION:An irradiation field of an object 3 to be measured with X-rays from a pulse X-ray generator 1 is limited by a collimator 2. X-rays, transmitting the object 3 to be measured and a sleeping bed 4, enters an image intensifier 5 as a transmitting information and the X-rays, converted into a transmitting optical image, are collected by an optical system 6 and enter a filter 7 which is made of a memory material such as photochromatic glass and is reduced in a transmissivity as a result of blackening corresponding to luminace of light. Light passing through the filter is converted into a digital signal by a two- dimentional detector 8, and an A/D converter 9 to store it in a picture recoder 10. The electric processing of the stored signal permits the reproduction of a picture, which is excellent in a density resolution, without the reduction in transmitting information of the object to be measured. |
