Color matching accuracy under multiple printing conditions

• US 20050200866A1
• Filed: 02/24/2005
• Published: 09/15/2005
• Est. Priority Date: 02/25/2004
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Hoshii, Jun, Noto, Keiichi
• Granted Patent: US 7,551,315 B2
• Time in Patent Office: Days
• US Class Current: 358/1.900
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence

Abstract

When creating recording level specifying data referred to during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device, standard color value data indicating an association relationship between ink tone values and color values under a standard printing condition is acquired; under a predetermined printing condition, and using at least one type of the aforementioned N types of ink drops for each ink color, patches are printed at a plurality of recording levels, and the color values of the printed patches are acquired; the aforementioned plurality of recording levels are associated with color values; and on the basis of association of the aforementioned plurality of recording levels and color values and of the aforementioned standard color value data, there is created recording level specifying data that specifies, for each ink color, an association relationship recording levels of the aforementioned N types of ink drops and tone values under the aforementioned predetermined printing condition.

Claims

1. A method for creating recording level specifying data, that creates recording level specifying data referred to when recording ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium with a printing device, the method comprising the steps of:

acquiring standard color value data indicating an association relationship between ink tone values and color values under a standard printing condition;

under a predetermined printing condition, printing patches at a plurality of recording levels, utilizing at least one type of said N types of ink drops for each ink color;

acquiring color values of the printed patches and associating said plurality of recording levels with color values; and

on the basis of associations of said plurality of recording levels with color values and of said standard color value data, specifying an association relationship for recording levels of said N types of ink drops and ink tone values under said predetermined printing condition, to create said recording level specifying data.

2. A method for creating recording level specifying data, that creates recording level specifying data referred to when recording ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium with a printing device capable of executing printing under a plurality of printing conditions, the method comprising the steps of:

acquiring standard color value data indicating an association relationship between tone values when representing color of pixels forming an image with tones for each ink color used by the printing device, and color values when printing is carried out with the same tone values under a standard printing condition;

printing a plurality of patches under a predetermined printing condition, by means of a plurality of target recording levels indicating recording levels of said N types of ink drops;

acquiring color value data indicating color values of printed patches; and

referring to the acquired color value data and said standard color value data, associating ink drop recording levels and target tone values such that the association relationship of tone values derived by carrying out printing under said predetermined printing condition at recording levels of said N types of ink drops to a plurality of target tone values is substantially equal to the association relationship of color values specified by said standard color value data to tone values.

3. Recording level specifying data creation method according to claim 2 wherein said standard color value data includes standard color conversion table data associating input tone values of a plurality of color components in a predetermined color system with tone values for each of said ink colors, and standard recording level specifying data indicating an association relationship of tone values for each of said ink colors and recording levels of said N types of ink drops;

and has been preadjusted so that color values derived when patches are printed, under a standard printing condition, at recording levels derived by conversion of said input tone values by means of said standard color conversion table data and said standard recording level specifying data coincide with color values corresponding to said input tone values.

4. Recording level specifying data creation method according to claim 2 wherein in said standard recording level specifying data, the association relationship of tone values for each of said ink colors and said ink drop recording levels is an association relationship common to all of said ink colors.

5. Recording level specifying data creation method according to claim 2 wherein said recording level specifying data is created individually for each said ink color.

6. Recording level specifying data creation method according to claim 2 wherein under each of said plurality of printing conditions, printing device resolution differs.

7. Recording level specifying data creation method according to claim 2 wherein under each of said plurality of printing conditions, the type of ink used by the printing device differs.

8. Recording level specifying data creation method according to claim 2 wherein during printing of said patches, tentative recording level specifying data specifying a tentative association relationship of the aforementioned tone values and recording levels of N types of ink drops is acquired;

and referring to the tentative recording level specifying data, a plurality of tone values are converted to said plurality of target recording levels.

9. Recording level specifying data creation method according to claim 8 wherein said tentative recording level specifying data is formed in advance under a plurality of printing conditions in consideration of the fact that ink level per unit ink drop differs under a plurality of printing conditions.

10. Recording level specifying data creation method according to claim 9 wherein, during creation of said recording level specifying data, with reference to said standard color value data, color values corresponding to a plurality of target tone values are acquired;

with reference to said tentative recording level specifying data and color values of said patches, recording levels of N types of ink drops needed to obtain color values corresponding to said target tone values are acquired; and

recording level specifying data under said predetermined condition is created by association thereof with said target tone values.

11. Recording level specifying data creation method according to claim 2 wherein tone values of each said ink color stored in said standard color conversion table are more unevenly distributed in a specific value range than in other values ranges;

and during creation of said recording level specifying data, tone values included in said specific value range are extracted more frequently as target tone values than those in other value ranges.

12. Recording level specifying data creation device that creates recording level specifying data referred to when recording ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium with a printing device capable of executing printing under a plurality of printing conditions, the recording level specifying data creation device comprising:

a standard color value data acquiring portion for acquiring standard color value data that indicates an association relationship between tone values when representing color of pixels forming an image with tones for each ink color used by the printing device, and color values when printing is carried out with the same tone values under a standard printing condition;

a patch printing portion for printing a plurality of patches under a predetermined printing condition, by means of a plurality of target recording levels indicating recording levels of said N types of ink drops;

a color value data acquiring portion for acquiring color value data indicating color values of printed patches; and

a recording level specifying data creation portion that, referring to the acquired color value data and said standard color value data, associates ink drop recording levels and target tone values such that the association relationship of tone values derived by carrying out printing under said predetermined printing condition at recording levels of said N types of ink drops to a plurality of target tone values is substantially equal to the association relationship of color values specified by said standard color value data to tone values.

13. Recording level specifying data creation program product for creating recording level specifying data referred to when recording ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium with a printing device capable of executing printing under a plurality of printing conditions, the recording level specifying data creation program product comprising:

program code for acquiring, from a predetermined recording medium, standard color value data that indicates an association relationship between tone values when representing color of pixels forming an image with tones for each ink color used by the printing device, and color values when printing is carried out with the same tone values under a standard printing condition;

program code for printing a plurality of patches under a predetermined printing condition, by means of a plurality of target recording levels indicating recording levels of said N types of ink drops;

program code for acquiring color value data indicating color values of printed patches; and

program code that, referring to the acquired color value data and said standard color value data, associates ink drop recording levels and target tone values such that the association relationship of tone values derived by carrying out printing under said predetermined printing condition at recording levels of said N types of ink drops to a plurality of target tone values is substantially equal to the association relationship of color values specified by said standard color value data to tone values.

14. Printing control method for controlling a printing device that records ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium under a plurality of printing conditions

wherein there is recorded onto a predetermined recording medium standard color conversion table data associating tone values of each of the plurality of color components in a predetermined color system with tone values of each of said ink colors, said table data being shared under said plurality of printing conditions;

and plurality of sets of recording level specifying data indicating association relationships between tone values of each of said ink colors and recording levels of said N types of ink drops, said data having said recording level determined for each of said plurality of printing conditions in such a way that output color of each tone value is generally common under said plurality of printing conditions;

the method comprising the steps of

acquiring image data in which colors of pixels forming an image are represented by tone values of a plurality of color components in said predetermined color system;

referring to said standard color conversion table to convert tone values of said image data into tone values for each ink color;

selecting, from among said plurality of sets of recording level specifying data, recording level specifying data that matches the printing condition at the time printing is executed, and converting color-converted tone values to recording levels of said N types of ink drops; and

carrying out printing of the converted recording levels.

15. Printing control device for controlling a printing device that records ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium under a plurality of printing conditions, the printing control device comprising:

a standard color conversion table data recording medium that records standard color conversion table data associating tone values of each of the plurality of color components in a predetermined color system with tone values of each of said ink colors, said table data being shared under said plurality of printing conditions;

a recording level specifying data recording medium that records a plurality of sets of recording level specifying data indicating association relationships between tone values of each of said ink colors and recording levels of said N types of ink drops, said data having said recording level determined for each of said plurality of printing conditions in such a way that output color of each tone value is generally common under said plurality of printing conditions;

an image data acquiring portion for acquiring image data in which colors of pixels forming an image are represented by tone values of a plurality of color components in said predetermined color system;

a color conversion portion that refers to said standard color conversion table to convert tone values of said image data into tone values for each ink color;

a tone value color conversion portion that selects from among said plurality of sets of recording level specifying data, recording level specifying data that matches the printing condition at the time printing is executed, and converts color-converted tone values to recording levels of said N types of ink drops; and

a printing execution portion for carrying out printing of the converted recording levels.

16. Printing control program product for controlling a printing device that records ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium under a plurality of printing conditions,

wherein there is recorded onto a predetermined recording medium standard color conversion table data associating tone values of each of the plurality of color components in a predetermined color system with tone values of each of said ink colors, said table data being shared under said plurality of printing conditions;

and plurality of sets of recording level specifying data indicating association relationships between tone values of each of said ink colors and recording levels of said N types of ink drops, said data having said recording level determined for each of said plurality of printing conditions in such a way that output color of each tone value is generally common under said plurality of printing conditions;

the program product comprising;

program code for acquiring image data in which colors of pixels forming an image are represented by tone values of a plurality of color components in said predetermined color system;

program code that refers to said standard color conversion table to convert tone values of said image data into tone values for each ink color;

program code that selects from among said plurality of sets of recording level specifying data, recording level specifying data that matches the printing condition at the time printing is executed, and converts color-converted tone values to recording levels of said N types of ink drops; and

program code for carrying out printing of the converted recording levels.

17. Printing control method for performing printing control with reference to recording level specifying data during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device, the method comprising the steps of:

referring to said recording level specifying data which specifies an association relationship between tone values for each ink color and recording levels of N types of ink drops in a target ink, in such a way as to compensate for color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink as a comparison target for said standard ink, in order to convert tone values of each ink color specified for each pixel making up image data into recording levels of said N types of ink drops; and

performing control of said printing device to record ink drops on a printing medium at said converted recording levels, to print a printed image.

18. Printing control method according to claim 17 wherein said recording level specifying data is data that specifies association relationships between tone values of each said ink color and recording levels of N types of ink drops for said target ink, so as to minimize differences between standard color value data derived by color measurement in a predetermined color space performed on a standard image printed onto a printing medium at standard ink drop recording levels when using the aforementioned standard ink, and color value data derived by color measurement in the same predetermined color space performed on a standard image printed onto a printing medium at standard ink drop recording levels when using the aforementioned target ink.

19. Printing control method according to claim 17 wherein, in said conversion, with reference to a color conversion table that specifies an association relationship of first image data representing an image on a per-pixel basis with tone values for each first elemental color, and tone values of each said ink color, tone values for each of said first elemental colors are color-converted to tone values for each of said ink colors;

and with reference to said recording level specifying data, tone values for said color-converted ink colors are converted to recording levels of N types of ink drops for said target ink.

20. Printing control method according to claim 19 wherein

there is provided a data recording area having recorded therein recording level specifying data that specifies, for each combination of ink used simultaneously by the aforementioned printing device, an association relationship of tone values of each said ink color and recording level of ink drops of the used inks, and said color conversion table used in common irrespective of the combination of inks used;

said color conversion is a process for referring to said common color conversion table to effect color conversion of said first image data to tone values of each said ink color; and

said conversion, among the recording level specifying data for each said ink combination, refers to recording level specifying data associated with the ink combination used by said printing device, to convert tone values of each said ink color to recording levels of said N types of ink drops.

21. Printing control method according to claim 17 wherein said recording level specifying data is data which specifies an association relationship between tone values of each ink color and recording levels of N types of ink drops for a target ink, in such a way as to compensate, for each of said N types of ink drops, for color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink with a standard printing device as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink with the same standard printing device.

22. Printing control method according to claim 17 wherein a monotonic index quantity is designated from among a plurality of index quantities derived from color value data during color measurement, performed in a predetermined color space, of index value selection images printed on a printing medium while varying the recording level of ink drops of the aforementioned standard ink, in such a way as the monotonic index quantity increases monotonically or decreases monotonically with respect to change in recording level of ink drops, said recording level specifying data is data that specifies an association relationship between tone values of each said ink color and recording levels of N types of ink drops for said target ink, in such a way as to minimize difference between a standard monotonic index quantity derived by color measurement, in the same predetermined color space, of a standard image printed onto a printing medium at standard ink drop recording level using said standard ink, and a monotonic index quantity derived by color measurement, in the same predetermined color space, of a standard image that has been printed onto a printing medium at a standard ink drop recording level using the said target ink.

23. Printing control method according to claim 22 wherein said plurality of index quantities are composed of the respective color component levels in the predetermined color space, and the color difference between a standard image printed using said standard ink or said target ink, and a printing medium which said standard image is printed onto.

24. Printing control method according to claim 22 wherein said recording level specifying data, where the monotonic index quantity that among said monotonic index quantities has the greatest difference with respect to change in recording level of ink drops of said standard ink is designated as selected index quantity, is data specifying an association relationship between tone values of each said ink color and recording levels of N types of ink drops for said target ink, in such a way as to minimize difference between a standard selected index quantity derived by color measurement of a standard image printed onto a printing medium at standard ink drop recording level using said standard ink, and a selected index quantity derived by color measurement of a standard image printed onto a printing medium at standard ink drop recording level using said target ink.

25. Printing control device that, during printing control of a printing device capable of recording onto a printing medium ink drops of N types (N is an integer of 2 or greater) of different ink levels for ink loaded at a predetermined loading location, acquires recording level of N types of ink drops, from tone values of each ink color representing ink usage level used by the printing device for each pixel making up image data, and uses this recording level to carry out printing control, the printing control device comprising:

tone values of each said ink color are data representing usage level of standard ink as a standard;

a standard image printing control portion that, with a target ink serving as a comparison target for said standard ink loaded at said loading location, carries out control of said printing device to print onto a printing medium a standard image at a standard ink drop recording level;

a color value data acquiring portion that acquires color value data when a standard image printed onto said printing medium is subjected to color measurement in a predetermined color space;

a recording level specifying data creating portion that compares standard color value data derived by color measurement in said predetermined color space of a standard image printed onto a printing medium at standard ink drop recording level when said standard ink is used, and color value data acquired by said color value data acquiring portion, and creates an association relationship of tone values of each said ink color to recording levels of N types of ink drops for said target ink, so as to compensate for differences between said standard color value data from said comparison result and said color value data acquired by said color value data acquiring portion;

a dot allocating portion that by referring to said recording level specifying data converts tone values of each said ink color to recording levels of N types of ink drops for said target ink; and

a printing control portion that performs control of said printing device to record onto a printing medium ink drops at recording levels converted by said dot allocating portion, to print a printed image.

26. Printing control device that during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device refers to recording level specifying data to carry out printing control, the printing control device comprising:

a dot allocating portion that, by referring to said recording level specifying data that specifies an association relationship between tone values for each ink color and recording levels of N types of ink drops in a target ink, in such a way as to compensate for color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink as a comparison target for said standard ink, in order to convert tone values of each ink color specified for each pixel making up image data into recording levels of said N types of ink drops, converts tone values of each ink color specified for each pixel making up image data to recording levels of said N types of ink drops; and

a printing control portion that performs control of said printing device to record onto a printing medium ink drops at recording levels converted by said dot allocating portion, to print a printed image.

27. Printing control program product that during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device refers to recording level specifying data to carry out printing control, the program product comprising:

program code that, by referring to said recording level specifying data that specifies an association relationship between tone values for each ink color and recording levels of N types of ink drops in a target ink, in such a way as to compensate for color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink as a comparison target for said standard ink, in order to convert tone values of each ink color specified for each pixel making up image data into recording levels of said N types of ink drops, converts tone values of each ink color specified for each pixel making up image data to recording levels of said N types of ink drops; and

program code that performs control of said printing device to record onto a printing medium ink drops at recording levels converted by said dot allocating portion, to print a printed image.

28. Recording level specifying data creation method for creating recording level specifying data referred to during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device, the method comprising the steps of:

acquiring color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink as a comparison target for said standard ink; and

creating recording level specifying data that specifies an association relationship between tone values for each ink color and recording levels of N types of ink drops in said target ink, in such a way as to compensate for color deviation for the respective N types of ink drops.

29. Recording level specifying data creation device for creating recording level specifying data referred to during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device, the creation device comprising:

a color deviation acquiring portion that acquires color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink as a comparison target for said standard ink; and

a recording level specifying data creating portion that creates recording level specifying data that specifies an association relationship between tone values for each ink color and recording levels of N types of ink drops in said target ink, in such a way as to compensate for color deviation for the respective N types of ink drops.

30. Recording level specifying data creation program product for creating recording level specifying data referred to during recording of ink drops of N types (N is an integer of 2 or greater) of different ink levels onto a printing medium by a printing device, the program product comprising:

program code that acquires color deviation between a standard image printed onto a printing medium at standard ink drop recording levels when using standard ink as a standard, and a standard image printed onto a printing medium at standard ink drop recording levels when using said target ink as a comparison target for said standard ink; and

program code that creates recording level specifying data that specifies an association relationship between tone values for each ink color and recording levels of N types of ink drops in said target ink, in such a way as to compensate for color deviation for the respective N types of ink drops.