Image processing method and apparatus

• US 20050063585A1
• Filed: 09/20/2004
• Published: 03/24/2005
• Est. Priority Date: 09/24/2003
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Matsuura, Takahiro
• Granted Patent: US 7,844,109 B2
• Time in Patent Office: Days
• US Class Current: 382/162
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence

Abstract

In order to allow a user to arbitrarily set color processing parameters which determine the color reproduction characteristics of a digital camera according to user'"'"'s preference, an image processing unit obtains color data by performing the same processing as that performed by the digital camera with respect to the sensed data of each color patch included in a color chart by using color processing parameters. A changing unit displays, on a display unit, a target data changing window which presents color data and the target data (the target color of color reproduction) of each color patch and allows the user to change the target data. A parameter editing unit edits color processing parameters so as to reduce the color difference between the changed target data and color data. A data input/output unit transmits the edited color processing parameters to the digital camera.

Claims

1. A method of generating a multidimensional lookup table for color processing of an image photographed by an image sensing device, comprising steps of:

inputting color data of color patches photographed by the image sensing device and target data representing target colors of the color patches;

performing color processing of the color data by using a color processing condition;

optimizing the color processing condition on the basis of the color-processed color data and the target data;

preparing the multidimensional lookup table by using the color processing condition; and

providing a user interface which expresses a positional relationship between the color-processed color data and the target data and accepts a change in the target data.

2. The method according to claim 1, wherein the multidimensional lookup table comprises a three-dimensional lookup table, and further comprising steps of:

determining whether or not outermost lattice points of primary and secondary colors in the three-dimensional lookup table are located inside a target color space;

moving an outermost lattice point determined as located outside the target color space into the target color space; and

relocating a lattice point near the outermost lattice point in accordance with a movement amount of the outermost lattice point.

3. The method according to claim 1, wherein the color processing condition comprises a matrix.

4. The method according to claim 1, further comprising a step of outputting the multidimensional lookup table to the image sensing device.

5. The method according to claim 1, wherein in the optimization step, the color processing parameter is so calculated as to minimize a sum of differences between the color-processed color data and the target data.

6. A method of generating a color processing condition for an image photographed by an image sensing device, comprising steps of:

inputting color data of color patches photographed by the image sensing device and target data representing target colors of the color patches;

setting a color processing condition in accordance with an instruction from a user;

performing color processing of the color data by using the color processing condition; and

optimizing the color processing condition, with the set color processing condition being an initial value, on the basis of the color-processed color data and the target data.

7. The method according to claim 6, further comprising a step of providing a user interface which expresses a positional relationship between the color-processed color data and the target data and accepts a change in the target data.

8. The method according to claim 6, further comprising a step of displaying an evaluation function for the color patches.

9. The method according to claim 6, wherein in the setting step, a color processing condition can be added in accordance with an instruction from the user.

10. An apparatus for generating a multidimensional lookup table for color processing of an image photographed by an image sensing device, comprising:

an inputting section, arranged to input color data of color patches photographed by said image sensing device and target data representing target colors of the color patches;

a processor, arranged to perform color processing of the color data by using a color processing condition;

an optimizer, arranged to optimize the color processing condition on the basis of the color-processed color data and the target data;

a preparation section, arranged to prepare the multidimensional lookup table by using the color processing condition; and

a provider, arranged to provide a user interface which expresses a positional relationship between the color-processed color data and the target data and accepts a change in the target data.

11. An apparatus for generating a color processing condition for an image photographed by an image sensing device, comprising:

an inputting section, arranged to input color data of color patches photographed by said image sensing device and target data representing target colors of the color patches;

a setter, arranged to set a color processing condition in accordance with an instruction from a user;

a processor, arranged to perform color processing of the color data by using the color processing condition; and

an optimizer, arranged to optimize the color processing condition, with the set color processing condition being an initial value, on the basis of the color-processed color data and the target data.

12. A computer program product stored on a computer readable medium comprising computer program code, for a method of generating a multidimensional lookup table for color processing of an image photographed by an image sensing device, comprising steps of:

inputting color data of color patches photographed by the image sensing device and target data representing target colors of the color patches;

performing color processing of the color data by using a color processing condition;

optimizing the color processing condition on the basis of the color-processed color data and the target data;

preparing the multidimensional lookup table by using the color processing condition; and

providing a user interface which expresses a positional relationship between the color-processed color data and the target data and accepts a change in the target data.

13. A computer program product stored on a computer readable medium comprising computer program code, for a method of generating a color processing condition for an image photographed by an image sensing device, comprising steps of:

inputting color data of color patches photographed by the image sensing device and target data representing target colors of the color patches;

setting a color processing condition in accordance with an instruction from a user;

performing color processing of the color data by using the color processing condition; and

optimizing the color processing condition, with the set color processing condition being an initial value, on the basis of the color-processed color data and the target data.

14. An apparatus for generating a color processing parameter for an image photographed by an image sensing device, comprising:

an inputting section, arranged to input color data of color patches photographed by the image sensing device and target data representing target colors of the color patches;

a provider, arranged to provide a user interface which edits an image processing condition for conversion of the color data into the target data; and

a generator, arranged to generate the image processing parameter on the basis of an operation result on the user interface, and optimizes the image processing parameter on the basis of a difference between a result obtained by performing image processing of the color data by using the generated image processing parameter and the target data.