| 摘要 |
PROBLEM TO BE SOLVED: To properly and efficiently conduct proper gray level control in response to various originals with different gray level conditions. SOLUTION: A signal color signal conversion means 21 extracts a single color signal of the CMY system from an RGB signal, and a histogram generating means 22 generates a gray level histogram on the basis of the gray level of each pixel of a digital image. In this case, a discrimination area for a background gray level and a maximum gray level is generated on the basis of a preset threshold value. A gray level class extraction means 31 extracts a background gray level class and a maximum gray level class, and a gray level correction curve generating means 3 generates a gray level correction curve on the basis of the result of classification by the gray level class extraction means 31. In the case of optionally adjusting the gray level correction curve, a 1st correction value and 2nd correction value setting means 33 newly sets a start point and an end point for generation of the gray level correction curve. A signal conversion means 34 converts the single color signal into a K signal. |
