JP2003264708A - Image processor, image processing method, program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor and an image processing method, capable of efficiently and accurately adjusting color balance, and to provide a program therefor and a recording medium therefor. <P>SOLUTION: In this image processor 20, a pattern sheet having a plurality of patches for which the amounts of respective element colors are changed in an adjustment gradation is generated by a pattern sheet generation means 20f, the generated pattern sheet is outputted to an image output device 30 and the change amount of the amounts of the respective element colors constituting a plurality of the patches is changed by a change amount changing means 20f. The pattern sheet is generated by changing the amounts of the respective element colors for the change amount changed in such a manner. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, an image processing method, a program and a recording medium capable of adjusting color balance of a printing apparatus.

[0002]

2. Description of the Related Art In a color printing apparatus such as an ink jet printer, four color inks of cyan (C), magenta (M), yellow (Y) and black (K), or light cyan (c) and light magenta are used. A color image is printed with 6 color inks including (m).
The print head that ejects these color inks can be an integrated type that ejects all color inks.
Since the yield is poor, a plurality of print heads are often used for each color.

However, when a plurality of print heads are used, the print heads vary from machine to machine even if they are color printers of the same model. Therefore, for example, when a plurality of color printers of the same model are connected to the network, if the same color correction is applied to each machine, the balance between the color inks may be lost depending on the machine.
Proper color reproduction becomes impossible.

Therefore, in the past, Japanese Patent Laid-Open No. 10-285
As disclosed in Japanese Laid-Open Patent Publication No. 415, in a color printing apparatus, a predetermined adjustment pattern is printed several times, and a pattern close to gray is selected and input from the printed patterns each time. Color conversion (color calibration) is performed so as to cancel the deviation of the output characteristics.

[0005]

However, the above-mentioned method is not accurate because it is a labor-intensive operation and a patch which is considered to be gray is selected depending on the subjectivity of the adjuster.

The present invention has been made to solve the above problems, and provides an image processing apparatus, an image processing method, a program, and a recording medium capable of performing more efficient and accurate color calibration. Is an issue.

[0007]

In view of the above problems, the invention of claim 1 is an image processing apparatus for adjusting color balance based on a pattern sheet output from an image output apparatus, wherein each element in adjustment gradation is adjusted. A pattern sheet generating unit that generates a pattern sheet having a plurality of patches with different color amounts and outputs the generated pattern sheet to the image output device; And a change amount changing means for changing the change amount of the amount.

According to the image processing apparatus configured as described above, the pattern sheet generating means first generates a pattern sheet having a plurality of patches in which the amount of each element color in the adjusted gradation is changed, and the generation is performed. The formed pattern sheet is output to the image output device, and the change amount changing unit changes the change amount of the amount of each element color forming the plurality of patches.

The invention described in claim 2 is the same as claim 1.
In the image processing device according to the item 1, the change amount changing unit changes the change amount to an amount smaller than the change amount at the time of generating the pattern sheet, after generating a predetermined pattern sheet,
The pattern sheet generating means is configured to generate a new pattern sheet based on the changed amount of change.

Further, the invention according to claim 3 is the image processing apparatus according to claim 1 or 2, wherein selection is made of a patch having a color closest to the adjustment color from the plurality of patches. Further comprising a patch selection receiving unit that receives the selection, and at least one of the amounts of the element colors forming the color of the patch selected by the patch selection receiving unit is the corresponding element color forming the color of the patch in the pattern sheet. When the amount is the maximum value or the minimum value, the change amount changing means is configured not to change the change amount.

The invention described in claim 4 is the same as claim 1.
Alternatively, in the image processing device according to the second aspect, the change amount changing unit is configured to change the change amount to be changed for each element color.

Further, the invention according to claim 5 is the image processing apparatus according to claim 3 or 4, wherein the pattern sheet generating means includes each element in which the plurality of patches form a color of each patch. The quantity of each element color is arranged in a two-dimensional area according to the quantity of color, and at least one of the quantity of each element color indicates the maximum value or the minimum value of the quantity of the corresponding element color forming the color of the patch in the pattern sheet. The patch is configured to generate and output a pattern sheet arranged so as to be located outside the two-dimensional area.

The invention according to claim 6 is the same as claim 1.
5. The image processing device according to any one of items 1 to 5,
The change amount changing unit is configured to change the change amount to be changed according to the gradation.

Further, the invention according to claim 7 is the image processing apparatus according to any one of claims 1 to 6, wherein the change amount changing means increases the change amount to be changed at lower gradations. To be configured.

The invention described in claim 8 is the same as claim 1.
7. The image processing apparatus according to any one of items 1 to 7,
The patch selection receiving unit further includes a unit that causes the image output device to output a patch for each gradation for which selection has been received.

Further, the invention according to claim 9 is the image processing apparatus according to any one of claims 1 to 8, wherein the patch element for each gradation is selected by the patch selection acceptance means. The storage means is further provided for storing the amount of color.

The tenth aspect of the present invention is the image processing apparatus according to any one of the first to ninth aspects, in which the elements of the patch for each gradation for which the selection is accepted by the patch selection acceptance means. It further comprises a correction curve generating means for generating a color balance adjustment correction curve for each element color based on the color change amount.

The eleventh aspect of the present invention is the image processing apparatus according to the tenth aspect, further comprising display means for displaying the correction curve generated by the correction curve generating means. .

The twelfth aspect of the present invention is the image processing apparatus according to any one of the first to eleventh aspects, wherein the adjustment color is an achromatic color.

The thirteenth aspect of the present invention is an image processing method for adjusting color balance based on a pattern sheet output from an image output device, wherein the amount of each element color is changed in the adjustment gradation. A pattern sheet generation step of generating a pattern sheet having a plurality of patches and outputting the generated pattern sheet to the image output device, and changing the amount of change in the amount of each element color forming the plurality of patches And a change amount changing step.

According to a fourteenth aspect of the present invention, there is provided a program for causing a computer to execute image processing for adjusting color balance based on a pattern sheet output from an image output device, wherein each of the element colors in the adjustment gradation is adjusted. A pattern sheet generation process of generating a pattern sheet having a plurality of patches of which the amount is changed and outputting the generated pattern sheet to the image output device, and an amount of each element color forming the plurality of patches A change amount changing process of changing the change amount is configured to be executed by the computer.

The invention according to a fifteenth aspect is a computer-readable recording medium, which is configured by recording the program according to the fourteenth aspect.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an image processing system to which an image processing control method according to an embodiment of the present invention is applied, and FIG. 2 is a schematic block diagram of a concrete hardware configuration example of the image processing apparatus. Is indicated by.

In FIG. 1, the image processing device 20 performs image processing on the color image data supplied from the image input device 10, and outputs the image-processed color image data to the image output device 30. Here, the color image data represents the intensity of each color of the color image while separating the color image for each predetermined element color, and is represented by gray when it is a chromatic color and mixed at a predetermined ratio. It consists of achromatic color and black.

The image processing apparatus 20 includes an output image generation unit 20j for generating an image to be output to the image output apparatus 30 and R;
An RGB conversion unit 20a for converting input RGB gradation data into R'G'B 'gradation data based on a GB correction curve; R'G'B' gradation with reference to a color conversion table Data is CMY ((cyan, magenta, yellow),
Or CMYK with black added to it, or CMYKc with light cyan (c) and light magenta (m) added to it
m) the color conversion unit 20b for converting the gradation data; and the CMY with reference to the color correction LUT (color conversion table).
(Or CMYK, or CMYKcm) gradation data is C'M'Y '(or C'M'Y'K', or C'M'Y'K'c ') suitable for a specific image output device.
m ') and a color correction unit 20c for converting the gradation data of C'M'Y' (or C'M'Y'K ', or C'M'Y'K'c'm'). 2) and a binarization unit 20d for converting the grayscale data of 2) into binary data.

The image processing apparatus 20 further includes an instruction unit 20.
e, the pattern sheet generation unit 20f, the correction curve generation unit 20g, the correction curve storage unit 20h, and the display unit 20i.
And are equipped with. Details of the processing of each of these components will be described later.

A specific example of the image input device 10 corresponds to the scanner 11, the digital still camera 12 or the video camera 14 in FIG. In addition, the image processing device 20
A specific example of
A computer system including a keyboard 23, a CD-ROM drive 24, a floppy (registered trademark) disk drive 25, a modem 26, a mouse 27, and the like is applicable. A specific example of the image output device 30 corresponds to the printer 31, the display 32, and the like.
However, in the embodiment, the printer 31 of the image output devices 30 will be described in detail. The modem 26 is connected to a public telephone line and connected to an external network via the same public communication line so that software and data can be downloaded.

The color balance adjusting program according to the present invention is usually recorded in a recording medium such as a floppy disk or a CD-ROM in a form readable by the computer 21 and distributed. The program is a media reading device (C
It is read by a D-ROM drive 24, a floppy disk drive 25, etc.) and installed in the hard disk 22. Then, the CPU is configured to read a desired program from the hard disk 22 as appropriate and execute a desired process. The color balance adjusting program itself according to the present invention also constitutes a part of the present invention.

In this embodiment, the scanner 11 and the digital still camera 12 as the image input device 10 are used.
Outputs RGB (green, blue, red) gradation data as image data, and the printer 31 as the image output device 30 outputs CMY (cyan, magenta, yellow) or black as gradation data. Binary data of added CMYK or CMYKcm obtained by adding light cyan (c) and light magenta (m) thereto is required as an input. Further, the display 32 requires RGB gradation data as an input. On the other hand, in the computer 21, the printer driver 21 corresponding to the operating system 21a, the printer 31, and the display 32 is provided.
b and a display driver 21c. Further, the image processing application 21d is controlled in execution of processing by the operating system 21a, and if necessary, cooperates with the printer driver 21b and the display driver 21c to execute predetermined image processing including color balance adjustment. Therefore, the specific role of the computer 21 as the image processing apparatus 20 is to generate output image data to be output to the image output apparatus 30, and adjust the color balance of the generated image data with the image output apparatus 30. Then, the RGB gradation data is input to create the RGB gradation data that has been subjected to the optimum image processing, and the RGB gradation data is displayed on the display 32 via the display driver 21c, and the CMY (or CMYK or CMYKcm) binary data is converted and printed by the printer 31.

FIG. 3 shows a schematic structure of a color ink jet printer 31. Four color inks of cyan (C), magenta (M), yellow (Y) and black (K) are used as printing inks. The print head unit 31a1 is provided for each color. Since the print head unit 31a1 is independent for each color in this manner, the output characteristics of the print head unit 31a1 vary due to the difference between the print head units 31a1, and the color balance is lost.

Regarding the configuration of the printer 31, in addition to the print head 31a consisting of four print head units 31a1, a print head controller 31b for controlling the print head 31a and a print head digit for moving the print head 31a in the digit direction. It is composed of a moving motor 31c, a paper feed motor 31d for feeding the print paper in the row direction, a print head controller 31b, a print head digit moving motor 31c, and a printer controller 31e which is an interface between the paper feed motor 31d and an external device. ing.

In this embodiment, the print head unit 31a1 is assigned to each of the four color inks, but as shown in FIG. 4, it is composed of three print head units 31a2 having two rows of print nozzles. You can also In this print head unit 31a2, the color ink to be supplied can be changed for each row of print nozzles. In this case, for the print head unit 31a2 on the left side in the figure, black ink (K) is supplied to both rows and the right side in the figure For the print head unit 31a2 of FIG. 1, the magenta color ink (M) is supplied to the left column and the yellow color ink (Y) is supplied to the right column.
Regarding a2, cyan ink (C) is supplied to the left column and the right column is not used. Here, the manufacturing error between the left column and the right column of each print head unit 31a2 is relatively small and can be almost ignored. Therefore, although there is no bias in the usage of magenta and yellow inks,
A similar bias may occur with cyan color ink. Further, the same print head unit 31a2 may be used to use six color inks as shown in FIG. In this case, for cyan and magenta, dark color inks (C, M) and light color inks (c, m) are used, and yellow and black are used for a total of six colors.

In the present embodiment, the ink jet type color printer 31 has been described, but a micro pump mechanism by a piezo element may be adopted for ejecting the color ink, or it may be provided on the inner wall surface of the ink ejection hole. A bubble may be generated by the heater provided and the ink may be ejected by the expansion pressure thereof.
Of course, the color ink may be ejected by a method other than these, or instead of ejecting the color ink, a thermal transfer type printing in which the color ink attached to the ink ribbon is melted and transferred by the heater is transferred. It is also applicable to heads and the like. However, in this case, the print head is different for each ink ribbon, and the present invention is applied to a case in which a machine difference occurs between print heads.

In this embodiment, the computer system for correcting the color image data is used for the printer 31, but as shown in FIG. 6, the color correcting system is built in the color printer 35, and the network etc. It is also possible to directly input and print the color image data supplied from the printer.

A first embodiment of the color balance adjusting program executed by the computer 21 will be described with reference to FIG. 7 and subsequent figures. FIG. 7 is a flowchart showing steps of processing executed by the color balance adjustment program.
According to the present color balance adjustment program, it is possible to adjust the balance of any adjustment color, but in the present embodiment, the processing when achromatic color is adjusted, that is, the processing in gray balance adjustment will be described.

First, when a gray balance adjustment instruction is received from the user via the instruction unit 20e of the image processing apparatus 20 shown in FIG. 1, the pattern sheet generation unit 20f generates a gray balance adjustment pattern sheet, The generated pattern sheet is printed by the printer as the image output device 30 via the output image generation unit 20j (step 40).

FIG. 9 shows an example of the printed pattern sheet 80. The pattern sheet 80 has four gradations, which are adjustment gradations used for gray balance adjustment, that is, 5 gradations.
Patch patterns for 1 gradation, 102 gradations, 153 gradations and 204 gradations are arranged. Here, the patch pattern is a pattern in which a plurality of patches having different hues are arranged. On the pattern sheet 80 shown in this figure, patch patterns 82, 84, 86 of 51 gradations, 102 gradations, 153 gradations and 204 gradations are sequentially arranged from the upper right to the lower side.
88 are arranged.

As described above, the gray balance adjustment according to the present embodiment uses four gradations at substantially equal intervals.
Therefore, the gray balance can be adjusted in a good balance in all gradations.

FIG. 10 shows the pattern sheet 80 shown in FIG.
A plurality of patches 82a forming a patch pattern 82 for 51 gray levels are schematically shown. In this figure, 51
Each patch 8 forming the patch pattern 82 in the step
The number shown in 2a represents the patch ID.
However, these numbers are not displayed on the actual pattern sheet. That is, in the patch pattern 82 for 51 gradations of the actually printed pattern sheet 80, the patch of the color defined by the RGB value corresponding to each patch ID in FIG. 11 is the patch ID shown in FIG.
Is displayed at the position.

The patch pattern 82 has a patch ID of 1
Centered on each patch (hereinafter referred to as "patch 1"), a plurality of patches indicating a color obtained by changing each value of the color indicated by patch 1 by a change amount of 2 are arranged in a hexagonal shape. Has been done. In addition, the R of the constituent colors of multiple patches
The value changes regularly by 2 along the R-axis,
Similarly, the G values of the constituent colors of a plurality of patches are along the G axis,
The B value regularly changes by 2 along the B axis.
Thus, the plurality of patches in the patch pattern 82 are
A gradation based on patch 1 is formed.

As described above, at least one of the RGB values of the constituent colors of the patch arranged on the outer periphery of the patch pattern 82 is the minimum value or the maximum value of the corresponding RGB values of the plurality of patches in the patch pattern 82. Is. That is, the patches in the patch pattern 82 indicate the colors within the hue range in which the hue is changed at predetermined intervals, with the patch 1 as a reference and the constituent colors of the patches arranged in the outer contour of the patch pattern 82 as boundaries. ing. Therefore, by using the patch pattern 82, it is possible to select a patch having a color closest to the achromatic color from the patches of the colors within the hue range with the constituent color of the patch 1 as a reference.

Further, the constituent colors of each patch 82a included in the patch pattern 82 shown in this figure are such that the RGB values are changed under the condition that the sum of the RGB values, that is, the lightness is constant. 51 gradation patch pattern 82 shown in the figure
In, the patches of the constituent colors are selected such that the sum of the R value, G value and B value is 153. When the sum of RGB values in all patches 82a is constant, γ in the image output device 30 is constant, and numerically, the brightness of all patches 82a is equal. Therefore, when the gray balance is adjusted by using the pattern sheet 80, the visual adjustment can be easily performed. As described above, in the gray balance adjustment, it is desirable that the total sum of RGB values of all the patches 82a forming the patch pattern 82 is a reference value (constant).

The configuration of each patch pattern 84, 86, 88 at the other gradations (102 gradations, 153 gradations and 204 gradations) included in the pattern sheet 80 is the 51st floor described with reference to this drawing. The configuration is similar to that of the tone patch pattern 82.

FIG. 11 shows RGB values corresponding to each patch ID of the patch pattern 82 in 51 gradations shown in FIG. That is, when the image processing apparatus 20 shown in FIG. 1 causes the image output apparatus 30 to output the pattern sheet 80, it is the RGB value of each patch that the pattern sheet generation unit 20f sends to the output image generation unit 20j. in this way,
In text data, patch ID and R of each patch
Since it is associated with the GB value, the image output device 30
Can print a pattern sheet 80 having a patch pattern in which patches of a predetermined hue and lightness are arranged at positions corresponding to patch IDs.

The pattern sheet generation unit 20f uses 5
In addition to the text data in 1 gradation, 102 gradations, 1
Text data in 53 gradations and 204 gradations is generated, and the output image generation unit 20j is caused to perform standard color correction, and then sent to the image output device 30.

Returning to FIG. 7, the step of image processing after the image output device 30 prints the pattern sheet 80 in step 40 will be described. The printed pattern sheet 80 and the reference sheet are compared (step 4
2) The patch showing the color closest to the achromatic color is selected from each of the plurality of patches in each gradation of the pattern sheet 80 (step 44, yes).

Here, the reference sheet is a sheet used as a reference when selecting a patch showing a color closest to an achromatic color from a plurality of patches for each gradation in the pattern sheet 80. The reference sheet has achromatic patches at each gradation at positions corresponding to the patch patterns 82, 84, 86, 88 of each gradation that the pattern sheet 80 has. That is, on the reference sheet, 51-tone achromatic patches are arranged at respective positions of a plurality of patches included in the 51-tone patch pattern 82 of the pattern sheet 80 shown in FIG. An achromatic patch of 102 gradations is arranged at each position of the plurality of patches included in 84. Similarly, achromatic color patches of 153 gradations and 204 gradations are arranged at corresponding positions.

When an achromatic color patch is printed by using a plurality of inks, there is a possibility that individual differences occur between the achromatic color patches of the reference sheet, such as variations in the ink composition ratio. Therefore, in order to print a more accurate achromatic patch, it is desirable that all achromatic patches forming the reference sheet are printed with K ink. Thereby, the individual difference of the reference sheet can be reduced.

In this way, by comparing the pattern sheet 80 and the patch and the achromatic color patch respectively arranged at the corresponding positions of the reference sheet, a plurality of patches included in the patch patterns 82, 84, 86, 88 of each gradation are obtained. Since the patch showing the color closest to the achromatic color is selected from among the patches of, the user can objectively select the patch showing the color close to the achromatic color without depending on the subjectivity.

In step 44, as an example, the same pattern sheet as the printed pattern sheet 80 shown in FIG. 9 is displayed on the display unit 20i, and the patch selected from the displayed pattern sheet is clicked with the mouse. For example, the selection of the patch in step 44 may be enabled.

When the patch is selected in step 44, the process for generating the pattern sheet is performed again. That is, when the patch arranged in the outer contour is selected from the patch pattern 82 printed the first time in step 46 (step 46, Yes), the pattern sheet generating unit 20 f configures the patch selected in step 44. The RGB value of the color is determined as the RGB value of patch 1 in the patch pattern to be generated next (step 5
2) Return to step 40. For the patch pattern included in the pattern sheet printed at this time, the patch of the color indicated by the RGB value determined in step 52 is referred to as patch 1, and a plurality of patches have RGB values of each patch along each RGB axis. And are arranged so as to change by two. The change amount of the patch included in the patch pattern generated here is 2, which is the same as the change amount of the previously created patch pattern.

The constituent colors of the patches arranged outside the patch pattern 82 are the colors at the boundary of the hue range of the patch pattern 82. Therefore, when the patch arranged in the outer contour is selected, the color indicated by the RGB value outside the hue range of the patch pattern 82 may be closer to an achromatic color. That is, the RGB value indicating an achromatic color may not exist in the hue range.

Therefore, when the outer patch is selected, the change amount of each RGB value is not changed, the RGB value which is the center of the patch pattern is changed, and the patch showing the color within the changed hue range is changed. From again, the patch showing the color closest to the achromatic color is selected again. As a result, it is possible to select a patch having a color closer to the achromatic color.

On the other hand, when a patch other than the patch arranged in the outer contour of the patch pattern is selected in step 44 (step 46, No), the pattern sheet generating section 20f generates the pattern sheet next time. RGB
1 is set as each change amount of (step 50). Next, the pattern sheet generating unit 20f determines the patch selected in step 44 as the patch 1 arranged at the center of the patch pattern when the pattern sheet is generated next time. That is, the RGB value of the patch selected in step 44 is determined as the RGB value of patch 1 of the patch pattern to be generated next (step 52),
Return to step 40.

FIG. 12 shows a patch pattern 84 of 51 gradations on the pattern sheet printed the second time. This figure shows the patch pattern 84 generated when the pattern 12 in the patch pattern 82 in the pattern sheet printed the first time is selected in step 52, and the RGB value of the patch 1 is 1 These are the RGB values of the pattern 12 in the patch pattern 82 for the second time.

The plurality of patches in the patch pattern 84 are arranged such that the RGB values of each patch change by 1 each along the RGB axes. The change amount 1 of each RGB value is a value set by the pattern sheet generating unit 20f in step 48. As described above, in the pattern sheet created the second time, the amount of change in each value of RGB is smaller than that in the pattern sheet of the first time, and the difference in the constituent color between the patches is small. At the first time, it is possible to select from patches with a relatively wide hue range, so it is easy to specify the hue range close to the constituent colors of the achromatic patch.

Further, the constituent colors of the achromatic patch can be included in the hue range determined by the patch sheet generated the second time. Therefore, in the second time, by selecting a patch having a color closest to the achromatic color from among a plurality of patches having a smaller change amount, it is possible to select a patch close to the achromatic color with higher accuracy.

As described above, since the patches are selected in two steps, it is possible to efficiently select the patch showing a color close to an achromatic color.

In addition, since the patch pattern generated in the second time is arranged centering on the patch selected from the patch patterns generated in the first time, it shows a color close to the constituent color of this patch. The patch closest to the achromatic color can be selected from the plurality of patches.

Returning to FIG. 7, the process from step 42 to step 48 is performed using the pattern sheet 84 printed the second time in step 40, and the process proceeds to step 54.

The processing from step 42 to step 52 is performed for the patch pattern of each gradation in the pattern sheet.

Returning to FIG. 7 again, when a patch is selected from the pattern sheet 84 printed the second time, the correction curve generator 20g selects the pattern sheet printed the second time by the designating unit 20e. A correction curve for each of the colors RGB is generated based on the patch (step 54).

Here, the generation of the correction curve will be described with reference to FIG. FIG. 13 shows the correction curve generation unit 2
The correction curve of each RGB color which 0g produces | generates is shown. For example, in step 46, the 51-level patch pattern 84 of the second printed pattern sheet shown in FIG.
From here, if patch 3 is selected as the achromatic patch,
The RGB values of the achromatic patch are (R = 48, G = 45, B
= 60). That is, the correction value is (R: -3,
G: -6, B: +9). In this case, the correction curve generation unit 20g sets the point R at the position of the coordinates (51, -3), the point G at the position of the coordinates (51, -6), and the coordinates (51, +9).
Plot point B at the position. Similarly, the correction curve generation unit 20g plots the coordinates, point (0,0) and point (255,0) based on the achromatic color patches selected in 102 gradations, 153 gradations and 204 gradations for each RGB. To do. Then, for gradations other than the plotted points, the plotted points for each color are connected by a spline curve to generate a correction curve. The connection between the points may be curved or straight.

Next, when an instruction from the outside is accepted via the instruction unit 20e (step 56, yes), the process according to the external instruction is performed (step 58). Step 5
The process in 8 will be described later.

In step 56, if no external command is accepted, the gray balance adjustment process ends.

The figure shows the subroutine in step 58 in FIG. That is, it is a flowchart of a program called by the computer 21 when an external command is received.

When the printing of the gray balance adjustment result pattern sheet is instructed through the instruction section 20e (step 60, Yes), the adjustment result pattern sheet shown in FIG. 9 is printed (step 62), and the adjusted gray sheet is adjusted. You can check the balance.

When an instruction to save the RGB correction curve after the gray balance adjustment is given via the instructing section 20e (step 64, Yes), the RGB correction curve data after the gray balance adjustment is stored together with the file name. It is stored in the section 20h (step 66).

Further, when the graph display is instructed through the instructing section 20e (step 68, Yes), the RGB correction curve generated by the correction curve generating section 20g or the RGB stored in the correction curve storing section 20h. The correction curve is displayed on the display unit 20i (step 7).
0).

When the external command processing is completed as described above, the process returns to the color balance adjusting process which is the main routine, and the color balance adjusting process is completed.

As described above, since the patch showing the color closest to the desired color is selected stepwise by changing the precision, the patch showing the desired color can be selected more efficiently.

Although the embodiments have been described above, the technical scope of the present invention is not limited to the above description, and modifications or improvements may be added to the above embodiments.

As a first modified example, in the present embodiment, the pattern sheet is printed twice, and the change amount of the plurality of patches in the first pattern sheet is 2, and the second pattern sheet is changed. However, the number of times the pattern pattern sheet is printed and the amount of change of the plurality of patches in the pattern sheet printed each time are not limited to this.

As a second modification, the generation, printing and patch selection of the pattern sheet may be repeated until the selected patch shows gray. For example, change amount 4, 3
Pattern sheets are generated in order with the settings of 2 and 2, and the change amount is 2
If it is determined that the selected patch in the pattern sheet with the setting of 1 indicates gray, the pattern sheet generation may be ended here, and the color balance adjustment may be performed using the selected patch.

As a third modification, the change amount of each RGB value of a plurality of patches in the patch pattern may be different according to the gradation. For example, when it is known in advance that the color balance is largely deviated in the low gradation, the change amount may be increased in the lower gradation. This allows efficient color balance adjustment.

As a fourth modification, the amount of change in each RGB value of a plurality of patches in the patch pattern may be different for each color. For example, the change amount 1 of R and the change amount 2 of G and B may be set.

As a fifth modified example, in the present embodiment, the amount of change in each value of RGB is all reduced in step 48, but the degree of the reduction is not limited to this embodiment. Absent. For example, the amount of change in one color of RGB or the amount of change in two colors may be reduced.
For example, when the change amount of each of RGB is 2, the change amount of R and G is 2 and the change amount of B is 1 as the next change amount.
It may be set to.

As a sixth modification, the form of the pattern sheet is not limited to this embodiment. As another example, the pattern sheet has, for example, 6 gradations,
It may have patch patterns in more gradations, and for example, gradation differences between gradations may not be evenly spaced. For example, when a gradation region in which the color balance is likely to shift is known in advance, the gradation difference in that gradation region may be reduced. As yet another example, the pattern sheet generator 20f may generate a pattern sheet in which only patch patterns for one gradation are arranged.

[Brief description of drawings]

FIG. 1 is a block diagram of an image processing system to which an image processing apparatus according to an embodiment of the present invention is applied.

FIG. 2 is a schematic block diagram showing a specific hardware configuration example of the image processing apparatus according to the embodiment of the present invention.

FIG. 3 is a schematic block diagram of a printer as an image output device that determines color shift in the image processing system.

FIG. 4 is a schematic block diagram showing a modified example of the printer.

FIG. 5 is a schematic block diagram showing a modified example of the printer.

FIG. 6 is a diagram showing a color printing apparatus connectable to a network or the like as another image output apparatus.

FIG. 7 is a flowchart showing processing of a color balance adjustment processing program executed by the image processing apparatus.

FIG. 8 is a flowchart showing a subroutine of step 50 in FIG.

FIG. 9 is a diagram showing a pattern sheet.

FIG. 10 is a diagram showing patch patterns in 51 gradations of the pattern sheet generated and output for the first time.

FIG. 11 is a diagram showing a data structure of text data corresponding to a patch pattern in 51 gradations.

FIG. 12 is a diagram showing patch patterns at 51 gradations of the pattern sheet 80 generated and output for the second time.

FIG. 13 is a diagram showing correction curves for R, G, and B colors.

[Explanation of symbols]

10 Image input device 11 scanner 12 Digital still camera 14 video camera 20 Image processing device 20a RGB converter 20b color converter 20c color correction unit 20d binarization unit 20e Indicator 20f pattern sheet generator 20g correction curve generator 20h correction curve storage 20i display 20j Output image generator 21 computer 23 keyboard 24 CD-ROM drive 25 floppy disk drive 26 modem 27 mice 30 image output device 31 Printer 32 display

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 9/79 H04N 9/79 H 5C079 F term (reference) 2C087 AA15 AA16 AB05 AC05 AC07 BA12 BD36 2C262 AA02 AB17 BA20 BB03 BB27 CA07 FA12 FA13 5B057 AA11 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC01 CE17 5C055 AA14 BA03 BA06 BA07 BA08 DA01 EA05 EA06 HA19 HA37 5C077 MM27 MP08 PP32 PP33 PP37 PQ12 PQ22 TT05 5C079 HB01 MA03 LA23 H01

Claims (15)

[Claims] 1. An image processing apparatus for adjusting color balance based on a pattern sheet output from an image output apparatus, wherein a pattern sheet having a plurality of patches in which the amount of each element color is changed in adjustment gradation is generated. A pattern sheet generating means for outputting the generated pattern sheet to the image output device; and a change amount changing means for changing the change amount of each element color forming the plurality of patches, Image processing device. 2. The image processing apparatus according to claim 1, wherein the change amount changing unit generates a predetermined pattern sheet,
An image processing apparatus, wherein the change amount is changed to an amount smaller than the change amount at the time of generating the pattern sheet, and the pattern sheet generating unit generates a new pattern sheet based on the changed change amount. 3. The image processing apparatus according to claim 1, further comprising a patch selection receiving unit that receives a selection for selecting a patch having a color closest to the adjustment color from the plurality of patches. , At least one of the amounts of the element colors forming the color of the patch received by the patch selection receiving unit is the maximum value or the minimum value of the amounts of the corresponding element colors forming the color of the patch in the pattern sheet. In some cases, the change amount changing means does not change the change amount. 4. The image processing apparatus according to claim 1, wherein the change amount changing unit changes the change amount to be changed for each element color. 5. The image processing apparatus according to claim 3 or 4, wherein the pattern sheet generating unit is two-dimensional in accordance with the amount of each element color in which the plurality of patches make up the color of each patch. At least one of the amount of each element color arranged in the area
The patch showing the maximum value or the minimum value of the amount of the corresponding element color, one of which constitutes the color of the patch in the pattern sheet,
An image processing apparatus for generating and outputting a pattern sheet arranged so as to be located outside of the two-dimensional area. 6. The image processing apparatus according to claim 1, wherein the change amount changing unit changes the change amount to be changed according to gradation. 7. The image processing apparatus according to claim 1, wherein the change amount changing unit increases the change amount to be changed at a lower gradation. 8. The image processing apparatus according to claim 1, further comprising: a unit that causes the image output device to output a patch for each gradation for which selection has been accepted by the patch selection acceptance unit. An image processing apparatus provided. 9. The image processing apparatus according to claim 1, wherein the patch selection receiving unit stores the amount of element color of the patch for each gradation for which the selection is accepted. An image processing apparatus further comprising means. 10. The image processing apparatus according to claim 1, wherein the element color is based on a change amount of the element color in the patch for each gradation for which the patch selection receiving unit has accepted the selection. The image processing apparatus further includes a correction curve generation unit that generates a color balance adjustment correction curve for each. 11. The image processing apparatus according to claim 10, further comprising display means for displaying the correction curve generated by the correction curve generating means. 12. The image processing apparatus according to claim 1, wherein the adjustment color is an achromatic color. 13. An image processing method for adjusting color balance based on a pattern sheet output from an image output device, wherein a pattern sheet having a plurality of patches in which the amount of each element color is changed in adjustment gradation is generated. Then, an image having a pattern sheet generation step of causing the image output device to output the generated pattern sheet, and a change amount changing step of changing the change amount of the amount of each element color forming the plurality of patches, the image Processing method. 14. A program for causing a computer to execute image processing for adjusting color balance based on a pattern sheet output from an image output device, wherein a plurality of patches in which the amount of each element color is changed in the adjustment gradation is set. A pattern sheet generating process for generating a pattern sheet having the pattern sheet and outputting the generated pattern sheet to the image output device; and a change amount changing process for changing a change amount of each element color forming the plurality of patches. And a program that causes a computer to execute. 15. A computer-readable recording medium in which the program according to claim 14 is recorded.