| 摘要 |
PURPOSE:To perform the operation for correcting the relative relation between the video signal and the luminance of a CRT without relying on the visual sensation of an operator when the RI distribution image of a scintillation camera is displayed. CONSTITUTION:The luminance of a CRT 9 is detected by means of a luminance detector 15. It is then converted, through a luminance converter 16, into a gradation level which is compared, through a difference calculator 17, with values on a gradation conversion table 12 thus calculating a gradation difference 18. The gradation difference 18 is added, through an adder 14, to an output from the gradation table 12. The sum is fed to a D/A converter 13 thence fed back to a video signal.
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