True-color computer monitor preview of a color print

• US 7,525,685 B2
• Filed: 10/27/2004
• Issued: 04/28/2009
• Est. Priority Date: 10/27/2004
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Ng, Joh Joh, Chia, Chee Wai, Lin, Khee Boon, Maniam, Selvan
• Primary Examiner(s): Williams; Kimberly A
• Application Number:
  US10/974,205
• Publication Number:
  US 20060087666A1
• Time in Patent Office: 1,644 Days
• Field of Search: 358/1.9, 358/167, 358/518, 358/501, 358/504, 382/162, 345/604, 345/619, 715/273, 715/274
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/6011 with simulation on a subsidiary picture reproducer H04N1/622 takes precedence; matching two or more picture reproducers H04N1/6052

Abstract

A color printing system includes a color monitor and printer having different color gamuts. A color chart is printed out by the printer. A light source outputs light to the color printer and a color sensor detects the light reflected from the color chart printout. The sensor outputs sensor color values representing the light received from the color chart printout. A print-preview matrix is calculated from the monitor color chart values and the sensor color values. An image is input to and displayed by the monitor and is converted into a print-preview image using the print-preview matrix. The monitor displays the monitor image and the print-preview image before printing the image.

Claims

1. A color printing system comprising:

a color monitor having a first color gamut;

a color printer having a second color gamut different from the first color gamut;

a light source for projecting light upon a color chart printed by the color printer;

a color sensor for detecting light reflected from the printed color chart and generating therefrom, a set of sensor color values; and

a processor for;

computing a sensor matrix from the set of sensor color values received from the color sensor;

computing a monitor matrix from a set of monitor color chart values that are used for generating a reference image of the color chart on the color monitor;

calculating a print-preview matrix from the monitor matrix and the sensor matrix; and

using the print-preview matrix for generating a print-preview image on the color monitor whereby a viewer compares the print-preview image against the reference image and adjusts the print-preview image in accordance with a format characterized as a what-you-see-on-the-monitor is what-you-get-from-the-printer.

2. The system of claim 1, wherein the light source is an LED.

3. The system of claim 1, wherein the processor is part of a personal computer.

4. The system of claim 1, wherein the printed color chart comprises multiple colored squares.

5. The system of claim 1, wherein the processor calculates the print-preview matrix from a monitor matrix and a sensor matrix using an equation:

[sensor matrix]=[monitor matrix]×

[print-preview matrix].

6. The system of claim 5, wherein the equation uses at least 8 different color values to calculate the print-preview matrix.

7. The system of claim 5, wherein the monitor matrix includes a second order polynomial.

8. The system of claim 5, wherein the print-preview image is adjusted according to the equations:

pR=α

·

sR+(1−

α

)·

pR

pG=β

·

sG+(1−

β

)·

pG

pB=γ

·

sB+(1−

γ

)·

pB

where α

, β

, and γ

are user selected mapping strength values, pR, pG and pB are coefficients of the sensor matrix, and sR, sG and sB are coefficients of the monitor matrix.

9. The system of claim 1, wherein adjusting the print-preview image comprises adjusting colors of the print-preview image so that the difference between the colors of the print-preview image and colors of the reference image is reduced.

10. The system of claim 1, wherein calculating the print-preview matrix comprises solving a matrix equation of the form [sensor matrix]=[monitor matrix]×

[print-preview matrix] defined as;

11. The system of claim 10, wherein n=8.

12. The system of claim 10, wherein n=24.

13. The system of claim 1, wherein calculating the print-preview matrix comprises solving a matrix equation of the form [sensor matrix]=[monitor matrix]×

[print-preview matrix] defined as;

14. A method for color printing comprising:

printing a color chart using a color printer, the color printer having a second color gamut different from a first color gamut of a color monitor;

projecting light upon the printed color chart using a light source;

detecting light reflected from the printed color chart using a color sensor and generating therefrom, a set of sensor color values;

using a set of monitor color values for generating a reference image of the color chart on the color monitor;

calculating a monitor matrix from the set of monitor color values;

calculating, a sensor matrix from the set of sensor color values;

calculating a print-preview matrix from the monitor matrix and the sensor matrix;

displaying on the color monitor, beside the reference image, a print-preview image using the print preview matrix; and

comparing the print-preview image against the reference image for adjusting the print-preview image in accordance with a format characterized as a what-you-see-on-the-monitor is what-you-get-from-the-printer.

15. The method of claim 14, wherein the light source is an LED.

16. The method of claim 14, wherein the processor is part of a personal computer.

17. The method of claim 14, further comprising printing multiple colored squares to print the color chart.

18. The method of claim 14, further comprising printing the color chart onto paper.

19. The method of claim 14, wherein the light source and the color sensor are part of a scanner.

20. The method of claim 14, wherein the light source and the color sensor are part of the color printer.

21. The method of claim 14, wherein calculating the print-preview matrix makes use of the monitor matrix and the sensor matrix and an equation:

[sensor matrix]=[monitor matrix]×

[print-preview matrix].

22. The method of claim 21, wherein the equation uses at least 8 different color values to calculate the print-preview matrix.

23. The method of claim 21, wherein the monitor matrix includes a second order polynomial.

24. The method of claim 21, further comprising adjusting the print-preview image prior to printing according to the equations:

pR=α

·

sR+(1−

α

)·

pR

pG=β

·

sG+(1−

β

)·

pG

pB=γ

·

sB+(1−

γ

)·

pB

where α

, β

, and γ

are user selected mapping strength values, pR, pG and pB are coefficients of the sensor matrix, and sR, sG and sB are coefficients of the monitor matrix.

25. The method of claim 14, further comprising adjusting colors of the print-preview image so that the difference between the colors of the print-preview image and colors of the reference image is reduced.

26. A color printing system comprising:

a processor;

a color monitor having a first color gamut, the color monitor adapted to display color images based on image color values received from the processor including displaying a color chart based on monitor color chart values received from the processor;

a color printer having a second color gamut, the color printer adapted to print color images based on the image color values received from the processor including printing the color chart based on the monitor color chart values received by the processor; and

a color sensor adapted to sense light reflected from the printed color chart and provide sensor color values to the processor;

wherein the processor is adapted to;

generate a sensor matrix using the sensor color values;

generate a monitor matrix using the monitor color chart values;

generate a print-preview matrix based on an equation;

[sensor matrix]=[monitor matrix]×

[print-preview matrix];

generate print-preview image color values based on the image color values and the print-preview matrix; and

output the image color values and print-preview image color values corresponding to an image to be printed to the color monitor, such that both a monitor image and a print-preview image are displayed by the color monitor.

27. The printing system of claim 26, wherein the color sensor includes a light source for illuminating the color chart.

28. The printing system of claim 27, wherein the light source and the color sensor are components of a printer.

29. The printing system of claim 27, wherein the light source and the color sensor are components of a scanner.

30. The printing system of claim 26, wherein the monitor matrix represents a second order polynomial.

31. The printing system of claim 26, wherein the print-preview matrix is calculated according to the matrix equation:

32. The printing system of claim 31, further comprising an input device allowing a user to manually adjust the coefficients of the print-preview matrix to control the color mapping from the image color values to the print-preview image color values.

33. The printing system of claim 32, wherein the print-preview image is adjusted according to the equations:

pR=α

·

sR+(1−

α

)·

pR

pG=β

·

sG+(1−

β

)·

pG

pB=γ

·

sB+(1−

γ

)·

pB

where α

, β

, and γ

are user selectable mapping adjustment parameters, pR, pG, and pB are the coefficients of the sensor matrix, and sR, sG, and sB are the coefficients of the monitor matrix.

34. A printing system comprising:

a first display medium;

a print medium;

means for displaying a first color chart on the first display medium based on color chart values;

means for printing a second color chart on the print medium;

means for scanning the second color chart to generate sensor color values;

means for generating color mapping coefficients based on the color chart values and the sensor color values, the means comprising a processor for calculating a print-preview matrix from a monitor matrix based on the color chart values, and a sensor matrix based on the sensor color values, according to an equation;

[sensor matrix]=[monitor matrix]×

[print-preview matrix];

means for mapping image color values for an image to be printed to preview image color values based on the color mapping coefficients; and

means for displaying on the first display medium a first image according to the image color values and a second image according to the preview image color values.

35. The printing system of claim 34, wherein the means for scanning includes a light source for illuminating the second color chart and a light sensor for sensing light reflected from the second color chart.

36. The printing system of claim 35, wherein the light source and the light sensor are components of a printer.

37. The printing system of claim 35, wherein the light source and the light sensor are components of a scanner.

38. The printing system of claim 35, wherein the monitor matrix corresponds to a second order polynomial.

39. The printing system of claim 38, wherein the print-preview matrix is calculated according to the matrix equation:

40. The printing system of claim 39, further comprising an input means allowing a user to manually adjust the coefficients of the print-preview matrix to control color mapping from the image color values to the preview image color values.

41. The printing system of claim 40, wherein the coefficients of the print-preview matrix are adjusted according to the equations:

pR=α

·

sR+(1−

α

)·

pR

pG=β

·

sG+(1−

β

)·

pG

pB=γ

·

sB+(1−

γ

)·

pB

where α

, β

, and γ

are user selectable mapping adjustment parameters, pR, pG, and pB are the coefficients of the sensor matrix, and sR, sG, and sB are the coefficients of the monitor matrix.

42. A method for color printing comprising:

printing a color chart based on monitor color chart values;

scanning the printed color chart to obtain scanned color chart values;

generating a print-preview matrix by solving a matrix equation;

[scan matrix]=[display matrix]×

[print-preview matrix] where the [scan matrix] is a matrix of coefficients corresponding to the scanned color chart values, and the [display matrix] is a matrix of coefficients corresponding to the monitor color chart values;

generating print-preview image color values based on image color values and the mapping coefficients of the print-preview matrix; and

displaying a first image corresponding to the image color values and a second image corresponding to the print-preview image color values.

43. The method of claim 42, wherein the display matrix corresponds to a second order polynomial.

44. The method of claim 43, wherein solving the matrix equation comprises multiplying the scan matrix by the Moore Penrose pseudoinverse of the display matrix.

45. The method of claim 42, wherein generating the print-preview matrix comprises solving the matrix equation:

46. The method of claim 42, further comprising adjusting color mapping based on the first and second images.

47. The method of claim 46, wherein adjusting the color mapping comprises reducing visual differences between the second image and a corresponding printed image.

48. The method of claim 46, wherein adjusting the color mapping comprises enhancing the colors of the second image so that a corresponding printed image will have a desired appearance.

49. The method of claim 46, wherein the color mapping is adjusted according to the color mapping equations:

pR=α

·

sR+(1−

α

)·

pR

pG=β

·

sG+(1−

β

)·

pG

pB=γ

·

sB+(1−

γ

)·

pB

where α

, β

, and γ

are user selectable mapping adjustment parameters, pR, pG, and pB are the coefficients of the sensor matrix, and sR, sG, and sB are the coefficients of the monitor matrix.

50. A computer readable medium storing machine accessible instructions executable by a processor, the instructions comprising:

printing a color chart based on monitor color chart values;

scanning the printed color chart to obtain scanned color chart values;

generating a print-preview matrix by solving a matrix equation;

[scan matrix]=[display matrix]×

[print-preview matrix] where the [scan matrix] is a matrix of coefficients corresponding to the scanned color chart values, and the [display matrix] is a matrix of coefficients corresponding to the monitor color chart values;

generating print-preview image color values based on image color values and the mapping coefficients of the print-preview matrix; and

displaying a first image corresponding to the image color values and a second image corresponding to the print-preview image color values.

51. The computer readable medium of claim 50, wherein the display matrix corresponds to a second order polynomial.

52. The computer readable medium of claim 51, wherein solving the matrix equation comprises multiplying the scan matrix by the Moore Penrose pseudoinverse of the display matrix.

53. The computer readable medium of claim 50, wherein generating the print-preview matrix comprises solving the matrix equation:

54. The computer readable medium of claim 50, further comprising adjusting color mapping based on the first and second images.

55. The computer readable medium of claim 54, wherein adjusting the color mapping comprises reducing visual differences between the second image and a corresponding printed image.

56. The computer readable medium of claim 54, wherein adjusting the color mapping comprises enhancing the colors of the second image so that a corresponding printed image will have a desired appearance.

57. The computer readable medium of claim 54, wherein the color mapping is adjusted according to the color mapping equations:

pR=α

·

sR+(1−

α

)·

pR

pG=β

·

sG+(1−

β

)·

pG

pB=γ

·

sB+(1−

γ

)·

pB

where α

, β

, and γ

are user selectable mapping adjustment parameters, pR, pG, and pB are the coefficients of the sensor matrix, and sR, sG, and sB are the coefficients of the monitor matrix.