| 摘要 |
PURPOSE:To provide an optimal output picture by operating similar compression without destroying the shape of the chromatic range of a color light, operating lightness conversion for enlarging the chroma reproducing range of a printer when the chroma reproducing range is small, according to the lightness distribution of input picture data, and operating chroma compression. CONSTITUTION:Lightness unit chroma, range, and compressibility calculating means 1 and 2 calculates a chroma compressibility based on the maximum chromatic range of the chromatic range of the color light in each prescribed lightness range, and the chroma reproducing range of the outputting device. Also, a lightness conversion judging means 5 decides whether or not the lightness conversion when the chroma reproducing range of the outputting device is small is operated, based on the lightness distribution of color picture data calculated by a lightness distribution calculating means 4. When the lightness conversion is operated, a lightness conversion arithmetic means 3 operates the chroma compression to the color picture data lightness-converted by a lightness converting means 7 at a conversion factor calculated by a lightness conversion factor calculating means 6, at the chroma compressibility calculated by the means 2. Thus, it is possible to make the most of the color reproducing range of the outputting device, and to obtain the clear and optimal output picture. |
