To obtain an excellent halftone image by reducing longitudinal streaks, lateral streaks, stripes and non-uniformity which are generated due to a printer engine specific problem, in accordance with a gradation level.
There are provided a color conversion processing means for color-converting image data into gradation data of respective color materials of cyan, magenta, yellow and black that are three primary colors of color materials and outputting the gradation data; a storage means for storing a dot concentrated screen table defining a threshold longitudinally and laterally growing from a center dot for each of the color materials; and a screen processing means for comparing the gradation data of the respective color materials outputted from the color conversion processing means with screen tables of the respective color materials and performing screen processing, wherein the screen table defines the threshold by setting the growth order of dots while changing an aspect ratio of dots in a growth direction in accordance with a gradation value.
IKUMA TAKESHI
| JP2007082011A | 2007-03-29 | |||
| JP2006261976A | 2006-09-28 |
Teiji Tanaka
Takashi Koyama
Hideo Sugai
Kenji Aoki
Hiroshi Nagisawa
Akira Yonezawa
Tsutomu Iitaka
Takehiko Katayose