| US 7,580,156 B2 | ||
| Image processing system, image processing device, dot data processing device, and method and program product therefor | ||
| Toshiaki Kakutani, Nagano-ken (Japan) | ||
| Assigned to Seiko Epson Corporation, Tokyo (Japan) | ||
| Filed on Jun. 27, 2005, as Appl. No. 11/169,224. | ||
| Claims priority of application No. 2004-189866 (JP), filed on Jun. 28, 2004. | ||
| Prior Publication US 2006/0285165 A1, Dec. 21, 2006 | ||
| Int. Cl. G06K 15/00 (2006.01); H04N 1/40 (2006.01) | ||
| U.S. Cl. 358—3.13 [358/3.09; 358/3.14; 358/3.21] | 26 Claims |
| 1. An image processing system for performing specific image processing on image data and for outputting dot data for forming
dots on a recording medium based on the results of said image processing system, comprising:
correspondence relationship preparation unit that prepares in advance, for each group of pixels, each comprising a plurality
of pixels, a correspondence relationship between a representative tone value, which is a tone value that represents said group
of pixels, and a multilevel halftoning resultant value that represents the results of performing multilevel halftoning on
each individual pixel that structures said group of pixels, wherein each of a plurality of correspondence relationships is
defined as groups of threshold values that group together a number of threshold values equal to the number of pixels included
in said group of pixels, and said plurality of correspondence relationships is prepared comprising threshold values with different
values from a plurality of individual threshold values selected from a global dithering matrix having included therein a number
of threshold values that is larger than a number of tones in an image, laid out following specific characteristics, while
varying the order of the extraction locations;
representative tone value determining unit that splits said groups of pixels, sequentially extracted from said image, into
a plurality of regions and, for each region, determining a representative tone value for representing the tone value of said
region;
multilevel halftoning unit that uses said determined representative tone values for each region to obtain a multilevel halftoning
resultant value, for each of said regions, through referencing said correspondence relationships assigned to said groups of
pixels belonging to said regions;
sequence value specifying unit that specifies sequence values that indicate the sequence in which will be formed the dots
in each pixel in said pixel groups according to the correspondence relationships referenced when obtaining said multilevel
halftoning resultant values;
dot data generating unit that generates dot data indicating whether or not to form a dot for each pixel within each of said
regions based on said specified sequence value for said group of pixels to which region belongs and on said multilevel halftoning
resultant values obtained for each of said regions; and
output unit that outputs said dot data.
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