| 摘要 |
PROBLEM TO BE SOLVED: To eliminate gradation jump for a multi-gradation image, without conducting averaging processing by converting the gradation of multi-gradation image data representing the multi-gradation image. SOLUTION: It is designated that a darkest point Vls of an object range of gradation conversion is converted into a point Vld and a brightest point Vhs to a point Vhd respectively, on a histogram of original multi-value gradation image data. A gradation conversion means generates a lookup table for applying gradation conversion to the multi-gradation image data according to the designation. In this case, values Vs, Vd are pixel values before and after the conversion, Vfs, Vls and Vhd, Vld are brightest points and darkest points before and after the conversion. Gradation conversion image data are obtained by applying the gradation conversion to the original multi-gradation image data. Since a gradation jump exists in the data, gradation is interpolated to generate the multi-gradation image data whose gradation is interpolated. |
