Printing black and white reproducible colored stroke documents

• US 6,179,485 B1
• Filed: 11/18/1996
• Issued: 01/30/2001
• Est. Priority Date: 11/18/1996
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Harrington, Steven J.
• Primary Examiner(s): ROGERS, SCOTT A
• Application Number:
  US08/752,190
• Time in Patent Office: 1,534 Days
• Field of Search: 395/109, 395/110, 382/162, 382/165, 382/176, 382/200, 382/254, 382/259, 358/500, 358/501, 358/530, 358/401, 358/296
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/40012 Conversion of colour to monochrome

Abstract

A document containing colored strokes or lines is reproduced in a way to preserve the color intent if the reproduced document is copied on a black-and-white device. Dashed lines are generated for insertion into the stroke, with dashing patterns that reflect the original color of the stroke. Outlining in black or white, dependent on the stroke color, may be provided. If the stroke is wide enough, the color within the stroke may alternatively be reproduced with a black and white reproducible pattern.

Claims

1. A document reproduction system, for reproducing a document containing colored lines or strokes in a format enabling improved black and white copying, retaining color intent of the document, including:

a document input, receiving electronic documents having colored lines or strokes represented therein designated to be printed in a color other than black;

an image processing unit, processing said documents for printing and generating lines or stroke representations in a format retaining color if printed on a color printer, including a differentiating centerline overlaid on said stroke, whereby said representation retains color differentiation if printed on a black and white printer;

a printer, reproducing said new line or stroke representation in said document, so that when copied, the document retains color intent in terms of differentiation of areas of color.

2. The system as defined in claim 1, where said differentiating centerline is a new stroke filled with a pattern.

3. The system as defined in claim 1, where said differentiating centerline is a dashed new stroke.

4. The system as defined in claim 1, where said printer is a color printer, printing each color with a colorant in a limited set of thereof.

5. A method for reproducing a color document containing color lines or strokes in a format enabling improved black and white copying retaining color intent of the color document including:

receiving electronic documents having line or stroke representations therein designated to be printed in a color other than black;

generating a new line or stroke representation in format retaining color if printed on a color printer, including a differentiating centerline overlaid on said stroke, whereby color differentiation of the stroke is retained if said document is printed or copied exclusively in black and white;

reproducing said lines or strokes, which when copied on a black and white copier, retains color intent in terms of differentiation of areas of color.

6. The document reproduction system as defined in claim 5, where said differentiating centerline is a new stroke filled with a pattern.

7. The system as defined in claim 5, where said differentiating centerline is a dashed new stroke.

8. A method for reproducing a color document containing color lines or strokes in a format enabling improved black and white copying retaining color intent of the color document including:

receiving electronic documents having line or stroke representations therein designated to be printed in a color other than black;

generating at least one dashed line having a dash structure sized and spaced as a function of said color other than black;

generating a line or stroke representation in said color other than black, having said dashed lines overlaid thereon, said new line or stroke representation in format retaining color if printed on a color printer, and retaining color differentiation if printed on a black and white printer;

reproducing said line or stroke, which when copied or printed exclusively in black and white, retains color intent in terms of differentiation of areas of color.

9. The method of reproducing a color document as described in claim 8, wherein said at least one dashed line is generated with a dashed line color selected as a function of said color other than black.

10. The method of reproducing a color document as described in claim 9, wherein said dashed line color is black or white.

11. The method of reproducing a color document as described in claim 8, where said at least one dashed line is generated with at least two colors.

12. The method of reproducing a color document as described in claim 11, wherein said at least two colors include black and white.

13. The method as defined in claim 8, and including:

generating an outline for said line or stroke, and overlaying said outline at edges of said line or stroke.

14. The method as defined in claim 13, and including:

setting said outline to one of black or white in accordance with a luminance level of any background over which said lines or strokes are to be printed.

15. The method as defined in claim 8, and including:

setting said outline to one of black or white in accordance with a luminance level of said color other than black and white.

16. The method as defined in claim 8, wherein said function of said color other than black is defined in terms of red-green-blue components of said color.

17. The method as defined in claim 8, wherein for lines or strokes determined to be large, said color is replaced with a color pattern specific to said color.

18. A method for reproducing a color document containing color lines or strokes in a format enabling improved black and white copying retaining color intent of the color document including:

receiving electronic documents having line or stroke representations therein designated to be printed in a color other than black;

calculating luminance of each line or stroke;

using calculated luminance to set an outline color for each item of lines or strokes to black or white;

generating outlines for each item of lines or strokes, using said set outline color;

determining a thickness for each line or stroke;

as a function of the thickness of said lines of strokes, selecting one of;

generating a dashed line, having dashes sized and spaced as a function of the color; and

generating a colored pattern selected to represent said color, whenever determined size exceeds a predetermined threshold size;

reproducing said lines or strokes, with said color pattern, said outlines and said dashed line, whereby when copied or printed in black and white, retains color intent in terms of differentiation of areas of color.