| 摘要 |
PROBLEM TO BE SOLVED: To provide a copy image improved in the reproducibility of gradation by adopting an image information value which is correlated with the quantity of light as the image information value of an original image to be adopted at the time of gradation conversion. SOLUTION: An image information detecting part 1 is constituted, so as to maintain the linearity of an input image information value and an output image information value. The image information detecting part 1 detects an image information value Dn , correlated with the density of an original information 5 recorded on a recording medium having a prescribed characteristic curve (characteristic curve specifying the correlation between the image information value Dn correlated to density and an image information value Xn correlated to a quantity of light). Then, this image information value Dn is converted into the image information value Xn correlated to the quantity of light, while utilizing the characteristic curve of the record medium. A gradation control part 3 of an image-forming device converts the image information value Xn correlated to the quantity of light inputted to the recording medium for recording the original image 5 through a prescribed gradation conversion expression to a gradation strength value for the gradation control. |
