System and method for proofing a page for color discriminability problems

• US 20060132872A1
• Filed: 12/20/2004
• Published: 06/22/2006
• Est. Priority Date: 12/20/2004
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Beretta, Giordano B.
• Application Number:
  US11/017,405
• Publication Number:
  US 20060132872A1
• Time in Patent Office: Days
• US Class Current: 358/518
• CPC Class Codes: H04N 1/6052 Matching two or more picture signal generators or two or more picture reproducers
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only

Abstract

An automated method for proofing a page for color discriminability problems includes converting a first color of a first object appearing on the page and a second color of a second object appearing on the page to a perceptually uniform color space. The method includes identifying a difference between the first color and the second color in the perceptually uniform color space. The method includes comparing the difference to a threshold to determine if the first color and the second color are discriminable.

Claims

1. An automated method for proofing a page for color discriminability problems, the method comprising:

converting a first color of a first object appearing on the page and a second color of a second object appearing on the page to a perceptually uniform color space;

identifying a difference between the first color and the second color in the perceptually uniform color space; and

comparing the difference to a threshold to determine if the first color and the second color are discriminable.

2. The automated method of claim 1, wherein the first color and the second color are converted from a device dependent color space to the perceptually uniform color space.

3. The automated method of claim 1, wherein the first object is text and the second object is a colored background object.

4. The automated method of claim 1, wherein the first object is an image and the second object is a colored background object.

5. The automated method of claim 1, wherein the first and the second objects at least partially overlap on the page.

6. The automated method of claim 1, wherein the difference represents a number of just noticeable differences between the first color and the second color in the perceptually uniform color space.

7. The automated method of claim 6, wherein the first color and the second color are deemed to be discriminable if the difference between the first color and the second color is greater than a threshold number of just noticeable differences.

8. The automated method of claim 1, wherein the difference represents a difference in a number of lightness units between the first color and the second color in the perceptually uniform color space.

9. The automated method of claim 8, wherein the first color and the second color are deemed to be discriminable if the difference is greater than a threshold number of lightness units.

10. The automated method of claim 1, wherein the first object is an image, and wherein the step of converting a first color of a first object comprises averaging colors of the image in the perceptually uniform color space to obtain a representative color for the image that is used in the step of identifying a difference.

11. The automated method of claim 1, wherein the first object is an image, and wherein the step of converting a first color of a first object comprises averaging colors of a periphery portion of the image in the perceptually uniform color space to obtain a representative color for the image that is used in the step of identifying a difference.

12. The automated method of claim 1, and further comprising:

generating an error indication if it is determined that the first color and the second color are not discriminable.

13. The automated method of claim 1, and further comprising:

determining a new discriminable color combination for the first and the second colors if it is determined that the first color and the second color are not discriminable.

14. The automated method of claim 13, wherein the step of determining a new discriminable color combination comprises:

adjusting a lightness value of at least one of the first color and the second color.

15. The automated method of claim 14, wherein the lightness value is adjusted based on the threshold.

16. The automated method of claim 15, wherein the lightness value is adjusted based on the threshold, and based on lightness values of the first and the second colors with respect to a bias lightness value.

17. The automated method of claim 16, wherein the bias lightness value represents an effective mid-point between light and dark regions on a lightness axis in the perceptually uniform color space.

18. The automated method of claim 14, wherein the step of determining a new discriminable color combination further comprises:

adjusting at least one of a chroma value and a hue value of at least one of the first color and the second color.

19. The automated method of claim 13, wherein the new discriminable color combination is determined from a limited palette of colors.

20. The automated method of claim 13, and further comprising:

providing a suggestion to a user to use the new color combination for the first and the second objects.

21. The automated method of claim 13, and further comprising:

automatically changing the first and the second colors to the new color combination.

22. The automated method of claim 1, wherein the page is generated by an automated page layout system.

23. The automated method of claim 1, wherein the page is generated in a variable data printing process.

24. A system for automatically identifying color discriminability problems of objects appearing on a page, the system comprising:

a memory for storing the page; and

a processor coupled to the memory for converting a first color associated with a first object on the page and a second color associated with a second object on the page to a perceptually uniform color space, and identifying whether the first color and the second colors are discriminable based on a difference between the first and the second color in the perceptually uniform color space.

25. The system of claim 24, wherein the first color and the second color are converted from a device dependent color space to the perceptually uniform color space.

26. The system of claim 25, wherein the difference represents a number of just noticeable differences between the first color and the second color in the perceptually uniform color space.

27. The system of claim 26, wherein the first color and the second color are deemed to be discriminable if the difference between the first and the second colors is greater than a threshold number of just noticeable differences.

28. The system of claim 24, wherein the difference represents a difference in a number of lightness units between the first color and the second color in the perceptually uniform color space.

29. The system of claim 28, wherein the first color and the second color are deemed to be discriminable if the difference between the first and the second colors is greater than a threshold number of lightness units.

30. The system of claim 24, wherein the first object is an image, and wherein converting a first color associated with a first object on the page comprises averaging colors of the image in the perceptually uniform color space to obtain a representative color for the image.

31. The system of claim 24, wherein the processor is configured to determine a new discriminable color combination for the first and the second colors if it is determined that the first color and the second color are not discriminable.

32. The system of claim 31, wherein the new discriminable color combination is determined by adjusting a lightness value of at least one of the first color and the second color in the perceptually uniform color space.

33. The system of claim 32, wherein the new discriminable color combination is determined by adjusting at least one of a chroma value and a hue value of at least one of the first color and the second color in the perceptually uniform color space.

34. A system for proofing a page for color discriminability problems, the page including a first object and a second object, the system comprising:

means for converting a first color associated with the first object and a second color associated with the second object to a perceptually uniform color space;

means for identifying a difference between the first color and the second color in the perceptually uniform color space; and

means for determining whether the difference is greater than a threshold, thereby indicating that the first color and the second color are discriminable.

35. A computer-readable medium having computer-executable instructions for performing a method of identifying color discriminability problems of objects appearing on a page to be printed, comprising:

identifying a first color associated with a first object appearing on the page;

identifying a second color associated with a second object appearing on the page;

converting the first and the second colors to a perceptually uniform color space; and

determining whether the first color and the second color are discriminable based on a difference between the first and the second colors in the perceptually uniform color space.

36. The computer-readable medium of claim 35, wherein the method further comprises:

determining a new discriminable color combination for the first and the second colors if it is determined that the first color and the second color are not discriminable.