| 摘要 |
PURPOSE:To make it possible to display efficiently a gradation range included in input information as to a range concerned, by equipping a modulating method which can set at a desire the position and range of a non-linear part of gradational data of input picture information. CONSTITUTION:The picture display unit of a computed tomography CT unit, etc., substitutes the light exposure value of an X-ray film with an input picture signal and film density with the display intensity of a display unit. Namely, minimum and maximum input signals are made to agree with the minimum intensity and maximum one of the display unit and an input signal value showing center display intensity is adjusted to display the entire range of the input signal, so that a range concerned can freely be selected. Further, the gradation degree of a display signal can freely be selected by adjusting scale factor 9. For the purpose, input picture signal (x) is inputted to logarithmic amplifier IC1 and the input range is adjusted by resistance VR1 while scale factor (a) is also adjusted by resistance VR2; and a value corresponding to center brightness is obtained by multiplier IC8, amplified and inputted to the intensity modulation input of CRT, thereby expressing X-ray film density. |
