Image processing apparatus and method, and image processing system

• US 20020126302A1
• Filed: 01/23/2002
• Published: 09/12/2002
• Est. Priority Date: 01/26/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Fukao, Suzuko
• Granted Patent: US 7,379,204 B2
• Time in Patent Office: Days
• US Class Current: 358/1.9
• CPC Class Codes: G06K 15/02 using printers
• CPC Class Codes: G06K 2215/0091 Outputting only video data, e.g. Hard copy of CRT display
• CPC Class Codes: G06K 2215/0094 Colour printing
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only

Abstract

If only a specific color and its nearby colors of image data are adjusted, density discontinuation occurs in the image as a whole. If masking is performed to avoid this problem, the adjustment range cannot be bounded, so the processing time increases. On an adjustment parameter designating unit, a user designates, as parameters, a reference color, the adjusted value of the reference color, and an adjustment region in a color space. A coordinate transformer transforms the coordinates of image data as an element of a color correction table, on the basis of a transformation matrix for transformation to an object color space. This transformation matrix is formed on the basis of the parameters by a transformation matrix calculator. If a region determinator determines that the image data is in the adjustment region, an adjusted value calculator calculates an adjusted value on the basis of the parameters.

Claims

1. An image processing apparatus for performing color adjustment for image data, comprising:

designating means for designating, as parameters, a reference color, an adjusted color of the reference color, and an adjustment region in a color space;

region determining means for determining whether input image data is in the adjustment region; and

adjusted value calculating means for calculating an adjusted value of the image data on the basis of the parameters, if said region determining means determines that the image data is in the adjustment region.

2. The apparatus according to claim 1, wherein the adjustment region is defined as a geometric figure in the color space.

3. The apparatus according to claim 2, wherein the geometric figure is an ellipsoid.

4. The apparatus according to claim 2, wherein the geometric figure is a polyhedron.

5. The apparatus according to claim 1, wherein said adjusted value calculating means calculates the adjusted value of the image data on the basis of an intersection of a straight line which connects the reference color and the image data, and the contour of the adjustment region.

6. The apparatus according to claim 5, wherein said adjusted value calculating means calculates the adjusted value of the image data such that the adjustment amount linearly changes with respect to a distance between the image data and the reference color in the color space.

7. The apparatus according to claim 5, wherein said adjusted value calculating means calculates the adjusted value of the image data such that the adjustment amount nonlinearly changes with respect to the distance between the image data and the reference color in the color space.

8. The apparatus according to claim 1, wherein the image data is an element of a correction table for color matching.

9. The apparatus according to claim 8, further comprising coordinate transforming means for transforming the image data into the coordinate system of a predetermined color space,

wherein said region determining means and said adjusted value calculating means each perform operations on the image data transformed into the predetermined color space.

10. The apparatus according to claim 9, wherein said designating means designates the parameters as values in said predetermined color space.

11. The apparatus according to claim 9, wherein said coordinate transforming means inversely transforms the adjusted value, in the predetermined color space, calculated by said adjusted value calculating means, into the color space coordinate system of the image data.

12. The apparatus according to claim 11, wherein said coordinate transforming means performs affine transformation and inverse transformation thereof.

13. The apparatus according to claim 9, further comprising:

transformation matrix calculating means for calculating, on the basis of the parameters, a transformation matrix used by said coordinate transforming means; and

matrix storage means for storing the transformation matrix.

14. The apparatus according to claim 9, wherein

said region determining means further determines that image data is inside a rectangular parallelepiped region containing the adjustment region in the color space, and

if said region determining means determines that the image data is inside the rectangular parallelepiped region, said coordinate transforming means transforms the coordinates of the image data.

15. An image processing method of performing color adjustment for image data, comprising:

the designation step of designating, as parameters, a reference color, an adjusted color of the reference color, and an adjustment region in a color space;

the region determination step of determining whether input image data is in the adjustment region; and

the adjusted value calculation step of calculating an adjusted value of the image data on the basis of the parameters, if it is determined in the region determination step that the image data is in the adjustment region.

16. An image processing system for performing color matching based on a color correction table in an image processing apparatus in which a monitor and a printer are connected, wherein said image processing apparatus comprises:

designating means for designating, as parameters, a reference color, an adjusted color of the reference color, and an adjustment region in a color space;

region determining means for determining whether image data which is an element of the color correction table is in the adjustment region; and

adjusted value calculating means for calculating an adjusted value of the image data on the basis of the parameters, if said region determining means determines that the image data is in the adjustment region.

17. A program which performs color adjustment for image data and can be executed on a computer, comprising:

a code of the designation step of designating, as parameters, a reference color, an adjusted color of the reference color, and an adjustment region in a color space;

a code of the region determination step of determining whether input image data is in the adjustment region; and

a code of the adjusted value calculation step of calculating an adjusted value of the image data on the basis of the parameters, if it is determined in the region determination step that the image data is in the adjustment region.

18. A recording medium recording the program according to claim 17.