Gray scale enhancements for color documents rendered on monochrome devices

• US 20040080789A1
• Filed: 10/28/2002
• Published: 04/29/2004
• Est. Priority Date: 10/28/2002
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Anderson, James E.
• Application Number:
  US10/281,933
• Publication Number:
  US 20040080789A1
• Time in Patent Office: Days
• US Class Current: 358/2.1
• CPC Class Codes: H04N 1/40012 Conversion of colour to monochrome

Abstract

Gray scale data converted from color data is enhanced prior to being rendered on a monochrome device. Different enhancements are applied to different image types based on selected monochrome output options. The enhancements to the gray scale data make close shades of gray more easy to distinguish. Advantages of the disclosed system and methods include improved gray scale documents that better convey visual information present in an original color document.

Claims

1. A processor-readable medium comprising processor-executable instructions configured for:

receiving a print job comprising color print data;

receiving monochrome output instructions having information regarding a plurality of image types;

generating gray scale data from the color print data;

distinguishing one or more image types within the print job;

enhancing the gray scale data for each image type according to the monochrome output instructions.

2. A processor-readable medium as recited in claim 1, wherein an image type is text, the enhancing further comprising converting gray scale data for the text into black data.

3. A processor-readable medium as recited in claim 1, wherein an image type is a bitmap, the enhancing further comprising:

determining that a first gray scale value in a first area is similar to a second gray scale value in a second area, the first area and the second area being adjacent to one another;

determining that a color corresponding to the first gray scale value is different than a color corresponding to the second gray scale value; and

increasing differentiation between the first gray scale value and the second gray scale value at adjacent edges of the first area and the second area.

4. A processor-readable medium as recited in claim 3, wherein the increasing differentiation further comprises:

increasing pixel data density at edges in the first area that are adjacent to the second area; and

decreasing pixel data density at edges in the second area that are adjacent to the first area.

5. A processor-readable medium as recited in claim 1, wherein an image type is a bitmap, the enhancing further comprising:

determining that a first gray scale value in a first area is similar to a second gray scale value in a second area, the first area and the second area being adjacent to one another;

determining that a color corresponding to the first gray scale value is the same as, but of a different intensity than, a color corresponding to the second gray scale value; and

leaving the first gray scale value and the second gray scale value as they are.

6. A processor-readable medium as recited in claim 1, wherein an image type is a graphics image type, the enhancing further comprising:

determining that a first gray scale value in a first area is similar to a second gray scale value in a second area, the first area and the second area being adjacent to one another;

determining that a color corresponding to the first gray scale value is different than a color corresponding to the second gray scale value; and

increasing differentiation between the first gray scale value and the second gray scale value.

7. A processor-readable medium as recited in claim 6, wherein the increasing differentiation further comprises:

increasing pixel data density of the first area; and

decreasing pixel data density of the second area.

8. A processor-readable medium as recited in claim 6, wherein the increasing differentiation further comprises:

decreasing pixel data density of the first area; and

increasing pixel data density of the second area.

9. A processor-readable medium as recited in claim 6, wherein the increasing differentiation further comprises:

increasing pixel data density of the first area; and

leaving pixel data density of the second area at its current level.

10. A processor-readable medium as recited in claim 6, wherein the increasing differentiation further comprises:

decreasing pixel data density of the first area; and

leaving pixel data density of the second area at its current level.

11. A processor-readable medium as recited in claim 6, wherein the increasing differentiation further comprises:

leaving pixel data density of the first area at its current level; and

decreasing pixel data density of the second area.

12. A processor-readable medium as recited in claim 6, wherein the increasing differentiation further comprises:

leaving pixel data density of the first area at its current level; and

increasing pixel data density of the second area.

13. A processor-readable medium as recited in claim 1, wherein an image type is text on a background, the text having a first gray scale value and the background having a second gray scale value, the enhancing further comprising:

increasing differentiation between the first gray scale value and the second gray scale value.

14. A processor-readable medium as recited in claim 13, wherein the increasing differentiation comprises:

increasing pixel data density of the text; and

decreasing pixel data density of the background.

15. A processor-readable medium as recited in claim 13, wherein the increasing differentiation further comprises:

decreasing pixel data density of the text; and

increasing pixel data density of the background.

16. A processor-readable medium as recited in claim 13, wherein the increasing differentiation further comprises:

increasing pixel data density of the text; and

leaving pixel data density of the background at its current level.

17. A processor-readable medium as recited in claim 13, wherein the increasing differentiation further comprises:

decreasing pixel data density of the text; and

leaving pixel data density of the background at its current level.

18. A processor-readable medium as recited in claim 13, wherein the increasing differentiation further comprises:

leaving pixel data density of the text at its current level; and

decreasing pixel data density of the background.

19. A processor-readable medium as recited in claim 13, wherein the increasing differentiation further comprises:

leaving pixel data density of the text at its current level; and

increasing pixel data density of the background.

20. A processor-readable medium comprising processor-executable instructions configured for:

recognizing within a bitmap image, a first area comprising pixel data of a higher density adjacent to a second area comprising pixel data of a lower density;

determining that a density difference between the higher density and the lower density is at or below a threshold value;

determining from original color data that a color of the first area is different than a color of the second area; and

exaggerating the density difference along adjacent edges of the first area and the second area.

21. A processor-readable medium as recited in claim 20, wherein the exaggerating further comprises:

increasing pixel data density on an edge of the first area that is adjacent to the second area; and

decreasing pixel data density on an edge of the second area that is adjacent to the first area.

22. A processor-readable medium comprising processor-executable instructions configured for:

recognizing within a vector graphics image, a first graphic area comprising pixel data of a higher density adjacent to a second graphic area comprising pixel data of a lower density;

determining that a density difference between the higher density and the lower density is at or below a threshold value;

determining from original color data that a color of the first graphic area is different than a color of the second graphic area; and

increasing differentiation between the first gray scale value and the second gray scale value.

23. A processor-readable medium as recited in claim 22, wherein the increasing differentiation is a technique selected from the group of techniques comprising:

increasing pixel data density of the first graphic area and decreasing pixel data density of the second graphic area;

decreasing pixel data density of the first graphic area and increasing pixel data density of the second graphic area;

increasing pixel data density of the first graphic area and leaving pixel data density of the second graphic area at its current level;

decreasing pixel data density of the first graphic area and leaving pixel data density of the second graphic area at its current level;

leaving pixel data density of the first graphic area at its current level and decreasing pixel data density of the second graphic area; and

leaving pixel data density of the first graphic area at its current level and increasing pixel data density of the second graphic area.

24. A processor-readable medium comprising processor-executable instructions configured for:

in an image type that includes text and a background, recognizing that text pixel data has a higher density than background pixel data, the background pixel data having a lower density;

determining that a density difference between the higher density and the lower density is at or below a threshold value;

determining from original color data that a color of the text is different than a color of the background; and

increasing the density difference between the text and the background.

25. A processor-readable medium as recited in claim 24, wherein the increasing the density difference is a technique selected from the group of techniques comprising:

increasing pixel data density of the text and decreasing pixel data density of the background;

decreasing pixel data density of the text and increasing pixel data density of the background;

increasing pixel data density of the text and leaving pixel data density of the background at its current level;

decreasing pixel data density of the text and leaving pixel data density of the background at its current level;

leaving pixel data density of the text at its current level and decreasing pixel data density of the background; and

leaving pixel data density of the text at its current level and increasing pixel data density of the background.

26. A processor-readable medium comprising processor-executable instructions configured for:

receiving color print data from an application program, the color print data in an application program format;

converting the color print data from the application program format into printer data in a printer-friendly format, the printer data formatted into one or more image types;

receiving monochrome output instructions regarding a plurality of image types;

sending the printer data and the monochrome output instructions to a printer.

27. A processor-readable medium comprising processor-executable instructions configured for:

receiving a print command from within an application program;

receiving color print data from the application program, the color print data in an application program format;

presenting gray scale enhancement options for printing various image types on a monochrome printer;

accepting user selections regarding the gray scale enhancement options;

formatting the color print data into printer-friendly data, the printer-friendly data comprising one or more image types;

sending the user selections and the printer-friendly data to the monochrome printer.

28. A processor-readable medium as recited in claim 27, wherein the gray scale enhancement options comprise:

a first option to have gray scale enhancements automatically set; and

a second option to have gray scale enhancements set by a user.

29. A processor-readable medium as recited in claim 28, wherein the second option further comprises:

for text image types, an option to print text in gray scale or in black;

for graph image types, an option to increase differentiation between gray scales of graphic components whose gray scale values are similar and whose original colors are different;

for bitmap image types, an option to increase differentiation of gray scales at adjacent edges of different color areas whose gray scale values are similar; and

for text with background image types, an option to increase differentiation between gray scale values of the text and the background.

30. A processor-readable medium comprising processor-executable instructions configured for:

receiving a print command from within an application program;

receiving color print data from the application program;

receiving user-input instructions for applying gray scale enhancements to various image types;

formatting the color print data into printer-friendly data, the printer-friendly data comprising gray scale data having one or more image types;

enhancing the gray scale data based on the user-input instructions and the one or more image types;

sending enhanced gray scale data to a monochrome printer.

31. A method of enhancing gray scale data for color documents being rendered on a monochrome device, the method comprising:

receiving a print job comprising color print data;

receiving monochrome output instructions having information regarding a plurality of image types;

generating gray scale data from the color print data;

distinguishing one or more image types within the print job;

enhancing the gray scale data for each image type according to the monochrome output instructions.

32. A method of enhancing gray scale data for color documents being rendered on a monochrome device, the method comprising:

recognizing within a bitmap image, a first area comprising pixel data of a higher density adjacent to a second area comprising pixel data of a lower density;

determining that a density difference between the higher density and the lower density is at or below a threshold value;

determining from original color data that a color of the first area is different than a color of the second area; and

exaggerating the density difference along adjacent edges of the first area and the second area.

33. A method of enhancing gray scale data for color documents being rendered on a monochrome device, the method comprising:

recognizing within a vector graphics image, a first graphic area comprising pixel data of a higher density adjacent to a second graphic area comprising pixel data of a lower density;

determining that a density difference between the higher density and the lower density is at or below a threshold value;

determining from original color data that a color of the first graphic area is different than a color of the second graphic area; and

increasing differentiation between the first gray scale value and the second gray scale value.

34. A method of enhancing gray scale data for color documents being rendered on a monochrome device, the method comprising:

in an image type that includes text and a background, recognizing that text pixel data has a higher density than background pixel data, the background pixel data having a lower density;

determining that a density difference between the higher density and the lower density is at or below a threshold value;

determining from original color data that a color of the text is different than a color of the background; and

increasing the density difference between the text and the background.

35. A method of enhancing gray scale data for color documents being rendered on a monochrome device, the method comprising:

receiving a print command from within an application program;

receiving color print data from the application program;

receiving user-input instructions for applying gray scale enhancements to various image types;

formatting the color print data into printer-friendly data, the printer-friendly data comprising gray scale data having one or more image types;

enhancing the gray scale data based on the user-input instructions and the one or more image types;

sending enhanced gray scale data to a monochrome printer.

36. A printer comprising:

a conversion module configured to convert color data into gray scale data;

monochrome output instructions having information regarding a plurality of image types; and

an enhancement implementation module configured to generate enhanced gray scale data from the gray scale data based on the monochrome output instructions.

37. A printer comprising:

color data received from an input device;

gray scale data generated from the color data by a conversion module executing on the printer; and

enhanced gray scale data generated from the gray scale data by an enhancement implementation module executing on the printer.

38. A printer as recited in claim 37, wherein the enhanced gray scale data further comprises bitmap image data having at least two image areas whose adjacent edges include exaggerated gray scale data.

39. A printer as recited in claim 37, wherein the enhanced gray scale data further comprises graphics image data having at least two graphic image areas adjacent to one another, at least one of the graphic image areas comprising gray scale data with increased pixel density.

40. A printer as recited in claim 37, wherein the enhanced gray scale data further comprises graphics image data having at least two graphic image areas adjacent to one another, at least one of the graphic image areas comprising gray scale data with decreased pixel density.

41. A printer as recited in claim 37, wherein the enhanced gray scale data further comprises text image data having gray scale data that is a shade of black.

42. A printer as recited in claim 37, wherein the enhanced gray scale data further comprises text on a background image data, wherein a gray scale shade of the text is darkened and a grayscale shade of the background is lightened.

43. A printer as recited in claim 37, wherein the enhanced gray scale data further comprises text on a background image data, wherein a gray scale shade of the text is lightened and a grayscale shade of the background is darkened.

44. A computer comprising:

color print data;

an image-type separation module configured to separate image types within the color print data;

an enhancement selection module configured to provide enhancement options for various image types; and

monochrome output instructions generated by the enhancement selection module according to user-selected enhancement options.

45. A computer as recited in claim 44, further comprising a conversion module configured to convert the color print data into gray scale data.

46. A computer as recited in claim 45, further comprising an enhancement implementation module configured to generate enhanced gray scale data from the gray scale data based on the monochrome output instructions.

47. A copier comprising:

a conversion module configured to convert color data into gray scale data;

monochrome output instructions; and

an enhancement implementation module configured to generate enhanced gray scale data from the gray scale data based on the monochrome output instructions.

48. A copier comprising:

a scanner platen;

color data received through the scanner platen;

a conversion module configured to convert the color data into gray scale data;

an enhancement implementation module configured to enhance the gray scale data into enhanced gray scale data; and

a copier engine configured to generate a hard-copy image of the enhanced gray scale data.

49. A copier as recited in claim 48, further comprising:

an image-type separation module configured to separate image types within the color data;

an enhancement selection module configured to provide enhancement options for various image types; and

monochrome output instructions generated by the enhancement selection module according to user-selected enhancement options.