| 摘要 |
PURPOSE:To attain digital image information effective for image diagnosis by subjecting a low-density area or an image information area corresponding to a low density and a high-density area or an image information area corresponding to a high density to conversion processing different in conversion characteristic from each other. CONSTITUTION:Amplification and adjustment are performed by inverting amplifiers 31 and 33 and an adder 32 so that an output signal according with the characteristic curve for low-density area is outputted. Amplification and adjustment are performed by a logarithmic converter 34, a subtractor 35, an inverting amplifier 34, and an adder 37 so that an output signal according with the characteristic curve for high-density area is outputted. If a image is in the low-density area, a comparator 38 discriminates that the output voltage of the amplifier 36 is higher than 0.5V density value, and connection of a changeover switch 39 to a terminal F is selected, and the output of the amplifier 33 is outputted to a terminal H. If the image is in the high-density area, the comparator 38 discriminates that the input voltage of the comparator 38 is lower than 0.5V density value, and the switch 39 is controlled to output the signal of the adder 37 to the terminal H.
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