| 摘要 |
PROBLEM TO BE SOLVED: To provide a blackening device for radiation images which can blacken an out-irradiation field area with higher accuracy than the blackening processing that is carried out based on the conventional irradiation field recognition processing having the unstable accuracy of recognition. SOLUTION: In regard to the image data showing a radiation image, a non- sharp mask signal Sus produced by a non-sharp mask of a prescribed size is calculated. Then an addition component calculation means 30 refers to a look-up table 50 where the correspondence is previously secured between the signal Sus and an addition component f (Sus) to calculate the component f (Sus) corresponding to the almost maximum value α in a range (0<Sus<β) where the signal Sus is small. An addition means 40 adds the component f (Sus) to the original image data, so that a part of low density corresponding to an out-irradiation field area is converted into the almost highest density. |
