Apparatus for generating two color printing data, a method for generating two color printing data and recording media

• US 7,085,006 B2
• Filed: 12/27/2001
• Issued: 08/01/2006
• Est. Priority Date: 12/28/2000
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yokoyama, Kazuyuki, Horiuchi, Yukiharu, Kitahara, Katsuhito
• Primary Examiner(s): Williams, Kimberly
• Assistant Examiner(s): Baker, Charlotte M.
• Application Number:
  US10/033,486
• Publication Number:
  US 20030002060A1
• Time in Patent Office: 1,678 Days
• Field of Search: 358/1.9, 358/501, 358/515, 358/518, 358/529, 358/537, 358/538, 358/1.18, 358/526, 358/1.1, 358/523, 382/167, 347/43, 347/9
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/56 Processing of colour picture signals H04N1/52 takes precedence

Abstract

A two-color print generating apparatus generates two-color print data based on color-converted image data in which the color of each pixel of full-color bit depth in an image is converted to a print color comprising a background color, a main color, or a secondary color. A color-reduced image data generator converts full-color image data to image data reduced to a specific number of colors. A color conversion unit generates color-converted image data in which the specified colors of the reduced-color image data are converted to colors that can be printed by the printer. A print data conversion unit converts the color converted color-converted image data to two-color print data. A color conversion selection unit sets the color conversion method and sets specific color conversion parameters based on the selected color conversion method. The processing of the invention can also be embodied as a method and/or specified as program instructions.

Claims

1. A method for generating two-color print data, comprising the steps of:

(a) reducing full-color digital image data to reduced-color digital image data by reducing the color of each pixel in the full-color digital image data to one of eight colors, wherein the color of each pixel in the reduced-color digital image data is defined by first, second and third primary colors, each primary color capable of exhibiting either a first intensity or a second intensity; and

(b) generating two-color print data by converting the color of each pixel in the reduced-color digital image data to a main color, a secondary color, or a background color according to the following rules;

(1) for each pixel whose three primary colors each exhibit its first intensity convert that pixel to the main color,

(2) for each pixel whose three primary colors each exhibit its second intensity convert that pixel to the background color, and

(3) for each pixel that does not satisfy either of conditions (1) or (2) convert that pixel to the secondary color.

2. The method of claim 1, wherein

the color of each pixel in the full-color digital image data is defined by the first, second and third primary colors, each primary color capable of exhibiting one of a plurality of intensities, and

step (a) comprises comparing the intensity of the first primary color of each pixel in the full-color digital image data with a first threshold, comparing the intensity of the second primary color of each pixel in the full-color digital image data with a second threshold, and comparing the intensity of the third primary color of each pixel in the full-color digital image data with a third threshold, and reducing the color of each pixel in the full-color digital image data based on the results of the comparisons.

3. The method of claim of 1, wherein the first, second and third primary colors are red, green, and blue.

4. The method of claim 1, wherein the first, second and third primary colors are cyan, magenta, and yellow.

5. A method for generating two-color print data, comprising the steps of:

(a) reducing full-color digital image data to reduced-color digital image data by reducing the color of each pixel in the full-color digital image data to one of a predetermined number of colors, wherein the predetermined number of colors is eight or less; and

(b) generating two-color print data by converting each color in the reduced-color digital image data to a main color, a secondary color, or a background color, wherein the converting is performed according to one of the following;

(1) uniformly converting each color in the reduced-color digital image data based on predefined conditions, or

(2) converting each color in the reduced-color digital image data based on a changeable conversion table linking each color to the main color, secondary color, or background color.

6. The method of claim 5, wherein

in step (a) each color in the full-color digital image data is reduced to a color defined by first, second and third primary colors, each primary color capable of exhibiting either a first intensity or a second intensity, and

step (b)(1) generates two-color print data by converting each color in the reduced-color digital image data to the main color, the secondary color, or the background color according to one of the following rules:

(1) for each color whose three primary colors each exhibit its first intensity convert that pixel to the main color,

(2) for each color whose three primary colors each exhibit its second intensity convert that pixel to the background color, and

(3) for each color that does not satisfy either of conditions (1) or (2) convert that pixel to the secondary color.

7. A two-color print data generating apparatus, comprising:

a reduced-color image data generating unit configured to reduce full-color digital image data to reduced-color digital image data by reducing the color of each pixel in the full-color digital image data to one of eight colors, wherein the color of each pixel in the reduced-color digital image data is defined by first, second and third primary colors, each primary color capable of exhibiting either a first intensity or a second intensity; and

a print data generating unit configured to generate two-color print data by converting the color of each pixel in the reduced-color digital image data to a main color, a secondary color, or a background color according to the following rules;

(1) for each pixel whose three primary colors each exhibit its first intensity convert that pixel to the main color,

(2) for each pixel whose three primary colors each exhibit its second intensity convert that pixel to the background color, and

(3) for each pixel that does not satisfy either of conditions (1) or (2) convert that pixel to the secondary color.

8. The apparatus of claim 7, wherein

the color of each pixel in the full-color digital image data is defined by the first, second and third primary colors, each primary color capable of exhibiting one of a plurality of intensities, and

the reduced-color image data generating unit is further configured to compare the intensity of the first primary color of each pixel in the full-color digital image data with a first threshold, compare the intensity of the second primary color of each pixel in the full-color digital image data with a second threshold, and compare the intensity of the third primary color of each pixel in the full-color digital image data with a third threshold, and reduce the color of each pixel in the full-color digital image data based on the results of the comparisons.

9. The apparatus of claim 7, wherein the first, second and third primary colors are red, green, and blue.

10. The apparatus of claim 7, wherein the first, second and third primary colors are cyan, magenta, and yellow.

11. A two-color print data generating apparatus, comprising:

a reduced-color image data generating unit configured to reduce full-color digital image data to reduced-color digital image data by reducing the color of each pixel in the full-color digital image data to one of a predetermined number of colors, wherein the predetermined number of colors is eight or less; and

a print data generating unit configured to generate two-color print data by converting each color in the reduced-color digital image data to a main color, a secondary color, or a background color, wherein the converting is performed according to one of the following;

(1) uniformly converting each color in the reduced-color digital image data based on predefined conditions, or

(2) converting each color in the reduced-color digital image data based on a changeable conversion table linking each color to the main color, secondary color, or background color.

12. The apparatus of claim 11, wherein

the reduced-color image data generating unit is configured to reduce each color in the full-color digital image data to a color defined by first, second and third primary colors, each primary color capable of exhibiting either a first intensity or a second intensity, and

the print data generating unit is configured to generate two-color print data by converting each color in the reduced-color digital image data to the main color, the secondary color, or the background color according to one of the following rules:

(1) for each color whose three primary colors each exhibit its first intensity convert that pixel to the main color,

(2) for each color whose three primary colors each exhibit its second intensity convert that pixel to the background color, and

(3) for each color that does not satisfy either of conditions (1) or (2) convert that pixel to the secondary color.

13. A computer-readable medium containing a program of instructions for directing a machine to perform a method of generating two-color print data, the program of instructions comprising:

(a) instructions for reducing full-color digital image data to reduced-color digital image data by reducing the color of each pixel in the full-color digital image data to one of eight colors, wherein the color of each pixel in the reduced-color digital image data is defined by first, second and third primary colors, each primary color capable of exhibiting either a first intensity or a second intensity; and

(b) instructions for generating two-color print data by converting the color of each pixel in the reduced-color digital image data to a main color, a secondary color, or a background color according to the following rules;

(1) for each pixel whose three primary colors each exhibit its first intensity convert that pixel to the main color,

(2) for each pixel whose three primary colors each exhibit its second intensity convert that pixel to the background color, and

(3) for each pixel that does not satisfy either of conditions (1) or (2) convert that pixel to the secondary color.

14. The computer-readable medium of claim 13, wherein

the color of each pixel in the full-color digital image data is defined by the first, second and third primary colors, each primary color capable of exhibiting one of a plurality of intensities, and

instructions (a) comprise comparing the intensity of the first primary color of each pixel in the full-color digital image data with a first threshold, comparing the intensity of the second primary color of each pixel in the full-color digital image data with a second threshold, and comparing the intensity of the third primary color of each pixel in the full-color digital image data with a third threshold, and reducing the color of each pixel in the full-color digital image data based on the results of the comparisons.

15. The computer-readable medium of claim of 13, wherein the first, second and third primary colors are red, green, and blue.

16. The computer-readable medium of claim 13, wherein the first, second and third primary colors are cyan, magenta, and yellow.