| 摘要 |
PURPOSE:To correct the gradations of X-ray image data, obtained by reading an X-ray photograph, in consideration of characteristics of an X-ray film. CONSTITUTION:The maximum density Dmax and minimum density Dmin of a main subject are detected from the image data obtained by reading the X-ray photograph. Then the density Dmax and density Dmin are converted into relative X-ray dosages Emax and Emin by using the characteristic curve D=f1(E) of the X-ray film. Optimum density values Dcmax and Dcmin, on the other hand, are converted into relative X-ray doses Ecmax and Ecmin by the characteristic curve D=f1(E). Here a conversion function D=f1(E) for the relative X-ray doses is set by using the values of the relative X-ray doses. Then the conversion function f2(E) is regenerated into a dimensional conversion function F(D)=f1(f2(f1<-1>(D)) for the density data by using the characteristic curve D=f1(E) and this is used as a gradation conversion function of the X-ray image data. |
