| US 7,576,888 B2 | ||
| Color reduction processing apparatus and color reduction method | ||
| Atsushi Sakai, Sakaki-machi (Japan); Teruyuki Takata, Ueda (Japan); and Tomohiro Kodama, Matsumo (Japan) | ||
| Assigned to Seiko Epson Corporation, Tokyo (Japan) | ||
| Filed on Jul. 28, 2004, as Appl. No. 10/900,687. | ||
| Claims priority of application No. 2003-203851 (JP), filed on Jul. 30, 2003. | ||
| Prior Publication US 2005/0062989 A1, Mar. 24, 2005 | ||
| Int. Cl. G06K 1/00 (2006.01); H04N 1/46 (2006.01) | ||
| U.S. Cl. 358—1.9 [358/3.06; 358/3.13; 358/515; 358/521; 358/534; 358/535; 358/536] | 23 Claims |
| 1. A color reduction processing device for converting full-color image data containing pixels, each defined by a combination
of three color components, to principal color print data of which black or another specified low-brightness color is the principal
color, and to secondary color print data of which a selected one of the three color components is the secondary color, the
device comprising:
a matrix storage unit configured to store a reference threshold value matrix;
a matrix configuration unit configured to set a first adjustment value that is mathematically applied to each threshold value
of the reference threshold value matrix to generate a first threshold value matrix, and to set a second adjustment value that
is mathematically applied to each threshold value of the reference threshold value matrix to generate a second threshold value
matrix;
a principal color data processing unit configured to multiply the values of the color components of each pixel in the full-color
image data by respective coefficients and add the resulting products for each pixel to produce a single weighted value for
each pixel, and to compare a matrix containing all of the weighted pixel values with the first threshold value matrix to generate
the principal color print data in the form of binary data; and
a secondary color data processing unit configured to compare the second threshold value matrix with matrices containing color
values only for the two color components in the full-color image data not designated as the secondary color respectively to
generate the secondary color print data in the form of binary data.
|