| 摘要 |
PURPOSE:To obtain a reproduced picture represented by a density and contrast for ease of diagnosis by adjusting the reproduced density responding to a specific signal region of an electric signal level converting radiant ray picture information to increase the contrast. CONSTITUTION:In the signal region from the minimum value Smin to the maxi mum value Smax of an electric signal level 3 converting the radiant ray picture information, the optical density D of the reproduced picture corresponding to the level S1 as shown in broken lines (a) or solid lines (b) is decreased and the reproduced density corresponding to the level S2 so as to increase the con trast between the S1 and S2 in comparison with the contrast between the Smin and the S1 and between the S2 and the Smax as to the S1, S2 in the relation of Smin<S1<S2<Smax. The Smin and Smax are reproduced by the optical density in the range of capry density and capry density +0.2 and in the range of 1.5-2.3 on the reproduced picture, respectively. The values S1, S2 are selected to satisfy the relation of Equation, where Emin, Emax, E1, E2 are X ray dose to the Smin, Smax, S1, S2, respectively.
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