IMAGE PROCESSING APPARATUS, IMAGE PROCESSING METHOD, AND STORAGE MEDIUM

• US 20200134403A1
• Filed: 10/18/2019
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kato, Minako
• Granted Patent: US 10,726,316 B2
• Time in Patent Office: Days
• CPC Class Codes: G06K 15/102 using ink jet print heads
• CPC Class Codes: G06K 15/188 with provisions for treating some of the print data differently
• CPC Class Codes: H04N 1/4015 of the reproducing head

Abstract

In conventional color shading (CS) processing for correcting color unevenness with high precision, even an image to preserve pure colors can be corrected to use inks of other colors. Color unevenness is more appropriately corrected to provide a favorable image by properly using pure color preservation information and pure color non-preservation information as color correction information for the CS processing.

Claims

1. An image processing apparatus configured to process image data for a recording apparatus, the recording apparatus being configured to record an image on a recording medium by applying ink from a recording device while relatively conveying the recording device and the recording medium in a second direction intersecting a first direction, the recording device including a first nozzle row in which a plurality of nozzles configured to discharge a first ink is arranged in the first direction and a second nozzle row in which a plurality of nozzles configured to discharge a second ink of different color from that of the first ink is arranged in the first direction, the first and second nozzle rows being arranged in the second direction, the image processing apparatus comprising:

a color conversion unit configured to color-convert image data including a plurality of components corresponding to a plurality of colors into image data including a plurality of components in a color space reproducible by the recording apparatus;

a color correction unit configured to color-correct the image data including the plurality of components color-converted by the color conversion unit into image data including a plurality of components by using color correction information for correcting a color shift due to a variation in a discharge characteristic of the nozzles; and

a generation unit configured to generate ink color data indicating amounts of application of the respective first and second inks based on the image data including the plurality of components color-corrected by the color correction unit,

wherein in a case where image data indicating a predetermined color having a hue corresponding to the first ink is color-corrected by using first information as the color correction information, ink color data generated based on the color-corrected image data indicating the predetermined color indicates that the first ink is applied and the second ink is not applied, and

wherein in a case where the image data indicating the predetermined color is color-corrected by using second information as the color correction information, the ink color data generated based on the color-corrected image data indicating the predetermined color indicates that the second ink is applied.

2. The image processing apparatus according to claim 1, wherein in a case where the image data indicating the predetermined color is color-corrected by using the second information, the ink color data generated based on the color-corrected image data indicating the predetermined color indicates that the first ink is applied.

3. The image processing apparatus according to claim 1,

wherein the color correction unit is configured to color-correct the image data in a color space including a plurality of elements, and

wherein in a case where image data indicating a point on a first line connecting a point representing a maximum value of the color corresponding to the first ink and a white point in the color space including the plurality of elements is input, the first information is information imposing a restriction that a point indicated by the color-corrected image data lies on the first line.

4. The image processing apparatus according to claim 3, wherein the generation unit is configured to, in a case where the point indicated by the image data color-corrected by the color correction unit lies on the first line in the color space including the plurality of elements, generate ink color data indicating that the first ink is applied and the second ink is not applied based on the color-corrected image data.

5. The image processing apparatus according to claim 3, wherein in a case where the image data indicating the point on the first line in the color space including the plurality of elements is input, the second information is information not imposing the restriction that the point indicated by the color-corrected image data lies on the first line.

6. The image processing apparatus according to claim 3, wherein the color space including the plurality of elements is a red, green, blue (RGB) color space.

7. The image processing apparatus according to claim 1, wherein the first ink is achromatic ink and the second is chromatic ink.

8. The image processing apparatus according to claim 1,

wherein the recording device further includes a third nozzle row in which a plurality of nozzles configured to discharge a third ink of different color from that of both the first and second inks is arranged in the first direction, the third nozzle row being arranged in the second direction,

wherein the ink color data generated by the generation unit further includes data indicating an amount of application of the third ink, and

wherein in a case where the image data indicating the predetermined color is color-corrected by using the first information, the ink color data generated based on the color-corrected image data indicating the predetermined color indicates that the third ink is not applied.

9. The image processing apparatus according to claim 8, wherein the first ink is yellow ink, and one of the second and third inks is cyan ink and the other is magenta ink.

10. The image processing apparatus according to claim 8, wherein the first, second, and third inks are any one of yellow ink, cyan ink, and magenta ink each.

11. The image processing apparatus according to claim 8,

wherein in a case where image data indicating a predetermined secondary color to be formed by using inks of any two colors of the first, second, and third inks is color-corrected by the color correction unit by using the first information, the ink color data generated based on the color-corrected image data indicating the predetermined secondary color indicates that the inks of the two colors are applied and the ink not included in the inks of the two colors of the first, second, and third inks is not applied, and

wherein in a case where the image data indicating the predetermined secondary color is color-corrected by the color correction unit by using the second information, the ink color data generated based on the color-corrected image data indicating the predetermined secondary color indicates that the first, second, and third inks are applied.

12. The image processing apparatus according to claim 11,

wherein the color correction unit is configured to color-correct the image data in a color space including a plurality of elements, and

wherein in a case where image data indicating a point on a first plane including two points representing maximum values of the colors corresponding to the inks of the respective two colors and a white point in the color space including the plurality of elements is input, the first information is information imposing a restriction that a point indicated by the color-corrected image data lies within the first plane, and the second information is information not imposing the restriction that the point indicated by the color-corrected image data lies within the first plane.

13. The image processing apparatus according to claim 12, wherein the generation unit is configured to, in a case where the point indicated by the image data color-corrected by the color correction unit lies within the first plane in the color space including the plurality of elements, generate ink color data indicating that the inks of the two colors are applied and the ink not included in the inks of the two colors of the first, second, and third inks is not applied based on the color-corrected image data.

14. The image processing apparatus according to claim 11, wherein the predetermined secondary color is any one of red, blue and green.

15. The image processing apparatus according to claim 1 wherein the recording device applies a plurality of types of inks of similar colors having different densities as the first ink.

16. The image processing apparatus according to claim 1, wherein the first ink is any one of orange, green, violet, and blue inks.

17. The image processing apparatus according to claim 1, wherein the color correction unit further includes a setting unit configured to set whether to use the first information or the second information as the color correction information.

18. The image processing apparatus according to claim 17, wherein the setting unit is configured to set either the first information or the second information based on information set by a user.

19. The image processing apparatus according to claim 17, wherein the setting unit is configured to set either the first information or the second information based on an attribute of the image data including the plurality of components.

20. The image processing apparatus according to claim 19 wherein the setting unit is configured to make a setting so that the first information is used for an object having a text or graphic attribute and the second information is used for an object having a picture attribute.

21. The image processing apparatus according to claim 17, wherein the setting unit is configured to make a setting so that the first information is used for an image of vector format and the second information is used for an image of bitmap format.

22. The image processing apparatus according to claim 17, wherein the setting unit is configured to make a setting so that the first information is used for an image having a relatively low frequency characteristic and the second information is used for an image having a relatively high frequency characteristic.

23. The image processing apparatus according to claim 17 wherein the setting unit is configured to make a setting to use the first information or the second information in units of contents within a page, areas, or pixels.

24. The image processing apparatus according to claim 1, wherein the recording device includes a first recording head having the first nozzle row and a second recording head having the second nozzle row.

25. An image processing method for processing image data for a recording apparatus, the recording apparatus being configured to record an image on a recording medium by applying ink from a recording device while relatively conveying the recording device and the recording medium in a second direction intersecting a first direction, the recording device including a first nozzle row in which a plurality of nozzles configured to discharge a first ink is arranged in the first direction and a second nozzle row in which a plurality of nozzles configured to discharge a second ink of different color from that of the first ink is arranged in the first direction, the first and second nozzle rows being arranged in the second direction, the image processing method comprising:

color-converting image data including a plurality of components corresponding to a plurality of colors into image data including a plurality of components in a color space reproducible by the recording apparatus;

color-correcting the color-converted image data including the plurality of components into image data including a plurality of components by using color correction information for correcting a color shift due to a variation in a discharge characteristic of the nozzles; and

generating ink color data indicating amounts of application of the respective first and second inks based on the color-corrected image data including the plurality of components,

wherein in a case where image data indicating a predetermined color having a hue correspond to the first ink is color-corrected by using first information as the color correction information, ink color data generated based on the color-corrected image data indicating the predetermined color indicates that the first ink is applied and the second ink is not applied, and

wherein in a case where the image data indicating the predetermined color is color-corrected by using second information as the color correction information, the ink color data generated based on the color-corrected image data indicating the predetermined color indicates that the second ink is applied.

26. A non-transitory computer-readable storage medium that stores a computer program comprising computer readable instructions which, when the program is executed by a computer, cause the computer to carry out the method of claim 25.