JP2002204366A - Apparatus of image processing, method thereof and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus of image processing, a method thereof and a recording medium capable of calibrating with more ease. SOLUTION: In an apparatus of image processing 20 according to the invention, at first, pattern sheets having more than one patch whose amount of each component color are changed in each gray-scale of more than one gray-scale are produced to output through an image output device. Then, after respectively selecting colorless patches from more than one patch at each gray-scale of the pattern sheets, corrective curves at each component color and corrective curves of colorless are produced according to changing amount of the component colors of the patches selected at each gray-scale. Then, the corrective curves are modified by a corrective curve modifying means, the pattern sheets are reproduced according to the modifications of the corrective curves to output to the apparatus, the colorless patches are selected at each gray-scale from more than one patch at each gray-scale of outputted reproduced pattern sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus, an image processing method, and a recording medium capable of adjusting a 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 six colors of ink to which (m) has been added.
The print head that discharges these color inks can be an integrated type that discharges all color inks,
Since the yield is deteriorated, a plurality of print heads are often used separately for each color.

[0003] However, when a plurality of print heads are used, the print heads vary from machine to machine even in the same type of color printing apparatus. For this reason, for example, when a plurality of color printing apparatuses of the same model are connected on a network, if the same color correction is performed on each machine, the balance between the respective color inks is lost depending on the machine,
Appropriate color reproduction becomes impossible.

For this reason, conventionally, Japanese Patent Application Laid-Open No. H10-285
As disclosed in JP-A-415, a predetermined adjustment pattern is printed several times, and each time a pattern close to gray is selected and input from among the printed patterns, so that the output in the color printing apparatus is obtained. Color conversion (color calibration) is performed so as to cancel out characteristic deviation.

[0005]

However, according to the above-described conventional color calibration method, it is necessary to print the adjustment pattern several times to perform the color calibration, which is a time-consuming operation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an image processing apparatus, an image processing method, and a recording medium that can more easily perform color calibration.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, an invention according to claim 1 is an image processing apparatus for adjusting a gray balance based on a pattern sheet and a correction curve output from an image output apparatus. Pattern sheet generating means for generating a pattern sheet having a plurality of patches in which the amounts of the respective element colors are changed at each gradation, and outputting the generated pattern sheet to the image output device; From multiple patches for each gradation,
Patch selection means for selecting an achromatic patch for each gradation; and a correction curve for each element color and an achromatic correction curve based on the amount of change in the element color in the patch selected for each gradation by the patch selection means. Correction curve generating means for generating the correction curve correction means for correcting the correction curve, based on the correction of the correction curve,
The pattern sheet generating unit regenerates the pattern sheet and outputs the pattern sheet to the image output device. From the plurality of patches for each gradation of the output regenerated pattern sheet, the patch selecting unit converts an achromatic patch to each floor. It is configured to select for each key.

According to the image processing apparatus configured as described above, which adjusts the gray balance based on the pattern sheet output from the image output apparatus, first, the pattern sheet generating means generates each of a plurality of gray levels. A pattern sheet having a plurality of patches in which the amounts of element colors are changed is generated, and the generated pattern sheet is output by the image output device.
An achromatic patch is selected for each gradation from a plurality of patches for each gradation on the pattern sheet. Then, the correction curve generation unit generates a correction curve for each element color and an achromatic color correction curve based on the amount of change of the element color in the patch selected for each gradation by the patch selection unit, and the correction curve correction unit The correction curve is modified. Based on the correction of the correction curve, a pattern sheet is regenerated by the pattern sheet generating means, and output to the image output device.From the plurality of patches for each gradation of the output regenerated pattern sheet,
The achromatic patch is selected for each gradation by the patch selecting means.

The invention described in claim 2 is the first invention.
The image processing apparatus according to claim 1, wherein the correction curve correction unit sets a control point capable of controlling a correction amount of the correction curve, and a correction amount of the correction curve at the set control point. And a correction amount setting unit for setting a correction curve based on the set control point and the set correction amount.

Further, the invention according to claim 3 is the image processing apparatus according to claim 2, further comprising display means for displaying a correction curve generated by the correction curve generation means. The control point setting means sets a control point based on the displayed correction curve, and the correction amount setting means sets a correction amount of the correction curve.

The invention described in claim 4 is the first invention.
The image processing apparatus according to any one of claims 1 to 3,
After changing the amount of each element color of the patch selected for each gradation by the patch selection means based on the correction curve corrected by the correction curve correction means, outputting the changed patch for each gradation to the image The apparatus further comprises means for causing the apparatus to output.

According to a fifth aspect of the present invention, there is provided the image processing apparatus according to any one of the first to fourth aspects, wherein the storage device stores the correction curve corrected by the correction curve correction unit. Means are further provided.

The invention according to claim 6 is the first invention.
The image processing apparatus according to any one of claims 1 to 5,
The amount of elemental color to be changed by the pattern sheet generating means is made different according to the gradation.

According to a seventh aspect of the present invention, there is provided the image processing apparatus according to any one of the first to sixth aspects, wherein the amount of the elementary color to be changed by the pattern sheet generating means is set to a lower gradation. It is configured to be large.

The invention described in claim 8 is the first invention.
The image processing apparatus according to any one of claims 1 to 7,
The pattern sheet generating means is configured to vary the amount of element colors to be changed for each element color.

According to a ninth aspect of the present invention, there is provided the image processing apparatus according to any one of the first to eighth aspects, wherein a display for displaying the pattern sheet generated by the pattern sheet generating means is provided. Further comprising means,
The patch selecting means is configured to select an achromatic patch for each gradation from a plurality of patches for each gradation of the displayed pattern sheet.

According to a tenth aspect of the present invention, there is provided an image processing method for adjusting a gray balance based on a pattern sheet and a correction curve outputted from an image output device. Generating a pattern sheet having a plurality of patches in which the amount of the pattern sheet has been changed, a pattern sheet generating step of outputting the generated pattern sheet to the image output device, and a plurality of patches for each gradation of the pattern sheet, A patch selection step of selecting an achromatic patch for each gradation, and a correction curve for each element color and an achromatic correction curve based on the amount of change in the element color in the patch selected for each gradation in the patch selection step And a correction curve correcting step of correcting the correction curve, and correcting the correction curve. Based on the pattern sheet generating step, the pattern sheet is regenerated and output to the image output device. From the plurality of patches for each gradation of the output regenerated pattern sheet, the achromatic patch is selected by the patch selecting step. Is selected for each gradation.

According to the image processing method configured as described above, which adjusts the gray balance based on the pattern sheet and the correction curve output from the image output device, first, each floor of a plurality of gradations is generated by the pattern sheet generating step. A pattern sheet having a plurality of patches in which the amount of each element color is changed in a tone is generated, and the generated pattern sheet is output by the image output device. , Achromatic patches are selected for each gradation. Then, in the correction curve generation step, a correction curve for each element color and an achromatic color correction curve are generated based on the amount of change in the element color in the patch selected for each gradation in the patch selection step. , The correction curve is modified. Based on the correction of the correction curve, the pattern sheet is regenerated by the pattern sheet generating step, and output to the image output device. From the plurality of patches for each gradation of the output regenerated pattern sheet, the patch An achromatic patch is selected for each gradation by the selection process.

Further, the invention according to claim 11 can be read by a computer in which a program for causing a computer to execute image processing for adjusting gray balance based on a pattern sheet and a correction curve outputted from an image output device is recorded. And generating a pattern sheet having a plurality of patches in which the amount of each element color is changed in each of a plurality of gradations, and outputting the generated pattern sheet to the image output device. A sheet generation process, a patch selection process of selecting an achromatic patch for each gradation from a plurality of patches for each gradation of a pattern sheet, and a patch selection process for selecting the element colors of the patches selected for each gradation. A correction curve that generates a correction curve for each elemental color and an achromatic color correction curve based on the amount of change Generation processing, a correction curve correction processing for correcting the correction curve, and, based on the correction curve correction, regenerating a pattern sheet by the pattern sheet generation processing and causing the image output device to output the pattern sheet. A program for causing a computer to execute a process of selecting an achromatic patch for each tone by the patch selection process from a plurality of patches for each tone of the regenerated pattern sheet is recorded and read by the computer. Is done.

The computer-readable recording medium configured as described above includes a program for causing a computer to execute image processing for adjusting gray balance based on a pattern sheet and a correction curve output from an image output device. Has been recorded. Then, by executing the program, first, a pattern sheet having a plurality of patches in which the amounts of the respective element colors are changed in each of the plurality of gradations is generated by the pattern sheet generation processing, and the generated pattern sheet is generated. The achromatic patch is output to the image output device, and an achromatic patch is selected for each gradation from a plurality of patches for each gradation on the pattern sheet by a patch selection process. Further, the correction curve generation processing generates a correction curve for each element color and an achromatic color correction curve based on the amount of change of the element color in the patch selected for each gradation by the patch selection processing. The correction curve is modified. Based on the correction of the correction curve, a pattern sheet is regenerated by the pattern sheet generation processing and output to the image output device. From the plurality of patches for each gradation of the output regenerated pattern sheet, the patch An achromatic patch is selected for each gradation by the selection process.

[0021]

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 one embodiment of the present invention is applied, and FIG. 2 is a schematic block diagram showing an example of a specific hardware configuration of the image processing apparatus. Is indicated by.

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

The image processing apparatus 20 converts an input RGB gradation data into R'G'B 'gradation data based on a correction curve; and an RGB conversion unit 20a with reference to a color conversion table. 'G'B' gradation data in CMY
(Cyan, magenta, yellow), or CMYK with black added thereto, or CMYKcm with light cyan (c) and light magenta (m) added thereto; CMY (or CMY) with reference to an LUT (color conversion table) for
K or CMYKcm) is converted into C′M′Y ′ (or C′M′Y ′) suitable for a specific image output device.
K 'or C'M'Y'K'c'm') color correction unit 20c for converting into gradation data; and the converted C'M '
Y '(or C'M'Y'K' or C'M'Y '
K'c'm '), and a binarization unit 20d for performing gradation conversion of the gradation data into binary data.

The image processing device 20 further includes an instruction unit 20
e, a pattern sheet generation unit 20f, a correction curve generation unit 20g, a correction curve storage unit 20h, and a display unit 20i.
And a color correction unit 20j. 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 digital still camera 12 or the video camera 14 in FIG. Further, specific examples of the image processing device 20 include a computer 21, a hard disk 22, a keyboard 2
3. CD-ROM drive 24, floppy (registered trademark) disk drive 25, modem 26 and mouse 2.
7 and the like. A specific example of the image output device 30 corresponds to the printer 31, the display 32, and the like. However, in the present embodiment, the printer 31 among 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 public communication line, and can download software and data.

The image processing control program according to the present invention comprises:
Normally, it is recorded on a recording medium such as a floppy disk or CD-ROM in a form readable by the computer 21 and distributed. The program is a media reader (CD-
ROM drive 24, floppy disk drive 25
Etc.) and installed on the hard disk 22. Then, the CPU is configured to appropriately read out a desired program from the hard disk 22 and execute a desired process. Note that the image processing program itself according to the present invention also constitutes a part of the present invention.

In this embodiment, a scanner 11 or a digital still camera 12 as an image input device 10 is 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) as gradation data or black to this. The input requires CMYK or binary data of CMYKcm to which light cyan (c) and light magenta (m) are added. The display 32 requires RGB gradation data as an input. On the other hand, in the computer 21, the printer driver 21b corresponding to the operating system 21a, the printer 31, and the display 32
And a display driver 21c. Also,
The image processing application 21d is controlled in its execution by the operating system 21a, and the printer driver 21b and the display driver 2
Predetermined image processing is executed jointly with 1c. Therefore, the specific role of the computer 21 as the image processing device 20 is to adjust the color balance with the output device,
R that receives GB gradation data and performs optimal image processing
Create GB gradation data and display driver 2
1c on the display 32, and
CMY (or CMY) via the printer driver 21b
(K or CMYKcm) and the printer 31 prints it.

FIG. 3 shows a schematic structure of a printer 31 of a color ink jet system, using four color inks of cyan (C), magenta (M), yellow (Y) and black (K) 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 vary due to the machine difference of each print head unit 31a1, and this is a factor that disturbs the color balance.

As for the configuration of the printer 31, there are a print head 31a comprising four print head units 31a1, a print head controller 31b for controlling the print head 31a, and a print head column for moving the print head 31a in the column direction. It comprises a moving motor 31c, a paper feed motor 31d for feeding print paper in the row direction, a print head controller 31b, a print head girder moving motor 31c, and a printer controller 31e serving as an interface between the paper feed motor 31d and external devices. ing.

In this embodiment, the print head units 31a1 are assigned to the four color inks, respectively. However, as shown in FIG. 4, the print head units 31a2 have two rows of print nozzles. You can also. In the 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 for both rows and the right side in the figure. Of the print head unit 31a2, the magenta ink (M) is supplied to the left column and the yellow ink (Y) is supplied to the right column.
For a2, cyan ink (C) is supplied to the left column and the right column is not used. Here, the manufacturing error between the left and right rows of each print head unit 31a2 is relatively small and can be almost ignored. Accordingly, although there is no difference in the amount of use of the magenta and yellow color inks, there is a possibility that the same amount of ink is used between the magenta and yellow color inks. Further, a configuration may be used in which six color inks as shown in FIG. 5 are used by using the same print head unit 31a2. In this case, cyan and magenta inks (C, M) and light inks
(c, m), and a total of six colors using yellow and black.

In the present embodiment, the color printer 31 of the ink jet system has been described. However, in order to discharge the color ink, a micro pump mechanism using a piezo element may be employed, or the ink jet system may be provided on the inner wall surface of the ink discharge hole. A bubble may be generated by the provided heater, and the ink may be ejected at the expansion pressure.
Needless to say, the color ink may be ejected by a method other than these methods, or a thermal transfer type printing in which the color ink attached to the ink ribbon is melted and transferred by a heater instead of ejecting the color ink. The present invention is also applicable to a head and the like. However, in this case, the print head is different for each ink ribbon, and the present invention is applied to a print head having a machine difference for each print head.

In the present embodiment, a computer system for correcting color image data for the printer 31 is used. However, as shown in FIG. A configuration is also possible in which the color image data supplied from is directly input and printed.

Hereinafter, referring to FIG.
Will be described.

First, when an instruction to adjust the gray balance is issued through the instruction section 20e of the image processing apparatus 20 shown in FIG.
The pattern sheet generator 20f generates a gray balance adjustment pattern sheet, and causes the printer as the image output device 30 to print the generated pattern sheet (step 40).

FIG. 8 shows an example of a printed pattern sheet. The numbers in each patch constituting the pattern sheet are data of R (red), G (green), B (blue) in order from the top.
(A value corresponding to the amount of each component). However, these numbers are not displayed on the actual pattern sheet.

As shown in FIG. 8, the current gray gradation pattern is displayed on the top row of the pattern sheet. That is, each gradation (A: 28 gradations, B: 56 gradations,
C: 84 tones, D: 112 tones, E: 140 tones, F:
(168 gradations, G: 196 gradations, H: 224 gradations), the colors are displayed when the amounts of the RGB components are all reference amounts (the same).

Also, the second row through the top of the pattern sheet
On the fourth line, a gradation pattern in which the RGB balance is changed is displayed.

The patches constituting the pattern sheet in the second row from the top are configured such that the amount of the B component at each gradation is greater than the reference amount by a different predetermined amount at each gradation. For example, the D gradation indicated by X (112
In the case of (gradation), the amount of the B component of all 9 (= 3 × 3) patches is a value 6 larger than the reference amount 112 of the D gradation 11
8.

The patches constituting the pattern sheet in the third row from the top are configured such that the amount of the B component at each gradation becomes the reference amount at each gradation. For example, Y
In the case of the D gradation (112 gradation), the amount of the B component of all 9 (= 3 × 3) patches is configured to be equal to the reference amount 112 of the D gradation.

The patches constituting the pattern sheet in the fourth row from the top are configured such that the amount of the B component at each gradation is smaller than the reference amount by a different predetermined amount at each gradation. For example, in the case of the D gradation (112 gradation) indicated by Z, the amount of the B component of all 9 (= 3 × 3) patches is a value that is 6 less than the reference amount 112 of the D gradation. It is configured so that

Further, the configuration of 9 (= 3 × 3) patches in each gradation of each of the second to fourth rows will be described. With respect to the three vertical columns, the amount of the R component in the left column is smaller than the reference amount by a predetermined amount different in each gradation, the amount of the R component in the center column is equal to the reference amount in each gradation, and the amount of the R component in the right column is one. The amount of the R component is larger than the reference amount by a different predetermined amount for each gradation. For example, in the case of nine patches indicated by X, the amount of the R component in the left column is smaller than the reference value (112) by a predetermined amount (6) in the D (112) gradation, and The amount of the component is equal to the reference amount (112) in each gradation, and the amount of the R component in the right column is D
(112) A reference amount (11) by a predetermined amount (6) in gradation
It is configured to be more than 2). Also, horizontal 3
With respect to the row, the amount of the G component in the upper row is larger than the reference amount by a predetermined amount that is different for each gradation, and the amount of the G component in the center row is equal to the reference amount in each gradation.
The amount of the G component in the lower row is configured to be smaller than the reference amount by a predetermined amount that is different for each gradation. For example, in the case of nine patches indicated by X, the amount of the G component in the upper one line is larger than the reference amount (112) by the predetermined amount (6) in the D (112) gradation, and When the amount of the component is equal to the reference amount (1
12) and the amount of the G component in the lower row is D (11
2) It is configured to be smaller than the reference amount (112) by the predetermined amount (6) in the gradation.

In step 40, the designation unit 20
The adjustment width (%) on which the predetermined amount is calculated can be designated by e. FIG. 9 shows an example of a user interface for specifying the adjustment width. In this embodiment, in the user interface shown in FIG.
The adjustment width of each gradation from H to H can be specified for each color within the range of 1 to 10 (%).

Here, the relationship between the adjustment width for each gradation and the predetermined amount (the shift amount of each element color component from the reference amount in a patch of a predetermined gradation) will be described.

Assuming that x (28 to 224) is a gradation value, y is an adjustment width (%), and z (x, y) is the predetermined amount, z (x, y) = (255−x) × y / 100… (1) In equation (1), (255−x) is almost proportional to the amount of ink used. That is, in the high-density area where the amount of used ink is large, the shift amount of each element color component of the patch at the predetermined gradation from the reference amount is increased so that the user can easily recognize the gray patch.

In this embodiment, the adjustment width (y) is set to 4%. The predetermined amount z in the D (112) gradation is:
From equation (1), z (112,4) = (255−112) × 4/100 = 6. Therefore, the value indicating the amount of each element color component of the 27 patches indicated by X, Y, and Z in FIG.
2, 112 + 6 = 118.

It should be noted that the value of the predetermined amount z can be changed for each color by changing the value of y for each element color component.

Next, the printing result of the gray balance adjustment pattern sheet printed in step 40 is visually observed, and for each of the eight gradations A to H,
From 9 (= 3 × 3) patches for each color of RGB,
The specifying unit 20e selects a patch that the user considers most gray (achromatic) (Step 42, Yes). As an example, the same pattern as the printed pattern sheet shown in FIG. 8 is displayed on the display unit 20i, and the displayed pattern is clicked with a mouse or the like, so that the patch can be selected in step 42. You can also.

Next, the correction curve generation section 20g generates a correction curve for each of the RGB colors and a gray correction curve (ALL) based on the patch selected by the specifying section 20e (step 44). A in the RGB correction curve
The correction value at each gradation point of H to H is the value of the RGB component of each selected patch (the value shown in the patch in FIG. 8), and the correction value at each gradation point of A to H in the gray correction curve (ALL). The initial value is 0 (zero). The correction values other than the gradation points A to H in the respective correction curves are obtained by connecting the gradation points with a spline curve.

As described above, the gray balance can be easily adjusted by selecting a patch which is considered to be gray for each gradation A to H for each color.

Then, when the instruction section 20e instructs the printing of the gray balance adjustment result pattern sheet (step 46, Yes), the adjustment result pattern sheet (gray patches in each gradation of A to H) shown in FIG. 10 is printed. (Step 48) The gray balance after the adjustment can be confirmed.

When the instruction section 20e instructs the storage of the correction curve after the gray balance adjustment (step 52, Yes), the correction curve data after the gray balance adjustment together with the file name are stored in the correction curve storage section 20.
h (step 52).

Further, when a graph display is instructed by the instructing section 20e (step 54, Yes), the correction curve generated by the correction curve generating section 20g or the correction curve stored in the correction curve storage section 20h is displayed on the display section. 20i is displayed (step 56). FIG. 11 shows an example of the correction curve displayed on the display unit 20i. At this time, the displayed correction curve can be corrected by the color correction process (step 57). According to the color correction processing, the gray balance can be adjusted even between the gradation points A to H, and more accurate gray balance adjustment can be performed.

Next, the color correction processing in step 57 will be described with reference to FIGS. The color correction process is performed by the color correction unit 20j based on the correction amount of the correction curve specified by the instruction unit 20e such as a mouse and the gradation value that can control the correction amount.

FIG. 12 is a flowchart for explaining the color correction processing in step 57. FIG.
FIG. 3 shows an enlarged R correction curve between the C gradation and the E gradation of the correction curve shown in FIG.

In FIG. 11, first, a correction curve to be corrected is selected from among the correction curves, and a control point at which the correction amount of the correction curve is controllable is selected from among the gradations A to H (step). 60, Yes). In this embodiment, as shown in FIG. 13, it is assumed that the R correction curve is selected as the correction target correction curve, and the D gradation is selected as the control point.

Next, the movement of the control point and the correction amount of the correction curve are designated by the pointing unit 20e such as a mouse (step 62). In this embodiment, as shown in FIG. 13, the control point is moved from D to D ′, and the correction amount is designated to be ΔR. Specifically, after clicking the line d indicating the gradation value D with the mouse and moving it to the line d 'indicating the gradation value D', the point D1 on the R correction curve at the gradation value D 'is Click to move to point D2 on line d 'corresponding to correction amount ΔR. Note that the control points can be moved within a range that does not overlap with adjacent control points. That is, the control point can be moved so that C <D ′ <E.

When the movement of the control point and the designation of the correction amount of the correction curve are determined (step 64, Ye)
s) Based on the gradation value of the moved control point and the correction amount of the correction curve, corrected correction curve data is generated by the color correction unit 20j (step 66). In the present embodiment, the R data at the D ′ gradation is represented by R ′ (R ′
= R + ΔR), data of a curve R ′ obtained by connecting three points C0 and E0 by a spline curve,
The corrected R correction curve data is generated by combining the C correction data and the R correction curve data of the E to 255 gradations.

Next, a correction curve based on the corrected correction curve data is displayed on the display section 20i (step 68).

If the pattern sheet is not to be printed again after the processing in step 68 (step 70, No), the flow returns to the processing in step 46 in FIG.

In step 46 after step 68, the instruction unit 20e instructs printing of the gray balance adjustment result pattern sheet (step 46, Ye
s) The adjustment result pattern sheet (gray patches in each gradation of A to H) is printed based on the corrected correction curve data generated in step 66 (step 4).
8) The gray balance after adjustment can be confirmed.

When the instruction section 20e instructs the storage of the correction curve after the color correction processing (step 52,
In Yes, the correction curve data after the color correction processing is stored in the correction curve storage unit 20h together with the file name (Step 52).

On the other hand, if the pattern sheet is to be printed again after the processing in step 68 (step 70, Yes), the pattern sheet data is modified and generated, and the pattern sheet is re-created based on the modified pattern sheet data. The sheet is printed (step 72), and step 42 in FIG.
Return to the processing of

Next, correction of the pattern sheet data will be described. When the control points and the correction amounts of the RGB correction curves are set in Steps 60 and 62 in FIG. 12, a predetermined amount (shift from the reference amount of each element color component in a patch of a predetermined gradation) is obtained from Expression (1). Amount) Z
(x, y) is required. That is, the gradation value of the control point selected in steps 60 and 62 corresponds to x, and the correction amount (%) of the correction curve corresponds to the adjustment width y.

Specifically, when the gradation value of the control point is 11
In the case of 2, when the correction amount of the correction curve is 8%, z (112,8) = (255−112) × 8/100 = 11 from Expression (1). Therefore, the values indicating the amounts of the respective component color components of the 27 patches indicated by X, Y, and Z are 112 + 11 = 123, 112, 112−11 = 101. In this way, by setting the control points and the correction amounts of the RGB correction curves in steps 60 and 62 in FIG. 12, the deviation of each element color component from the reference amount in a patch of a predetermined gradation of the generated pattern sheet is set. The quantity Z (x, y) can be changed.

On the other hand, when the control points and the correction amount of the gray correction curve ALL are set in steps 60 and 62 in FIG. 12, first, the reference amounts of the respective element color components in the patches of the predetermined gradation are corrected. Is done. That is, the gradation value of the control point selected in steps 60 and 62 is x1, and the correction amount of the correction curve is y1 (%).
Then, the corrected reference quantity x2 is obtained by the following equation: x2 = x1 × (1 + y1 / 100) (2)

Specifically, when the gradation value of the control point of the gray correction curve ALL is 112 (x1) and the correction amount of the correction curve is 4 (y1)%, the corrected value is obtained from Expression (2). The reference amount x2 is x2 = 112 × (1 + 4/100) = 116. From equation (1), Z (x2, which is the shift amount of each element color component from the reference amount in a patch of a predetermined gradation,
y1) is given by Z (x2, y1) = (255−166) × 0.04 = 6. Therefore, the value indicating the amount of each element color component of the 27 patches indicated by X, Y, and Z is 116 + 6 = 122, 116, 116-6 = 110.

After the pattern sheet is generated and printed again as described above, the processing from step 42 is repeated.

In this way, by setting the control point and the correction amount of the gray correction curve ALL in steps 60 and 62 in FIG. 12, the deviation of each element color component from the reference amount in a patch of a predetermined gradation is set. The quantity Z (x, y) can be changed. Changing Z (x, y), which is the shift amount of each element color component from the reference amount in a patch of a predetermined gradation, is equivalent to performing gray γ adjustment. According to this embodiment of the present invention, the RGB correction values are determined by selecting patches that are considered to be gray for each of the gray levels A to H in each of the colors in steps 40 and 42, and then the predetermined gray level is determined. Z, which is the shift amount of each element color component from the reference amount in the patch
Since (x, y) can be changed and a patch that can be considered as gray for each gradation in the corrected pattern sheet can be selected, gray gamma correction can be performed more easily.

[Brief description of the drawings]

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

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

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

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

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

FIG. 6 is a diagram illustrating a color printing device that can be connected to a network or the like as another image output device.

FIG. 7 is a flowchart for explaining an image processing program executed by the image processing apparatus 20.

FIG. 8 is a diagram illustrating an example of a printed gray balance adjustment pattern sheet.

FIG. 9 is a diagram illustrating an example of a user interface for specifying an adjustment width.

FIG. 10 is a diagram illustrating an example of an adjustment result pattern sheet.

FIG. 11 is a diagram illustrating an example of a correction curve displayed on a display unit 20i.

FIG. 12 is a flowchart illustrating a process of step 57.

FIG. 13 is an enlarged view of an R correction curve between the C gradation and the E gradation of the correction curve shown in FIG. 11;

[Explanation of symbols]

 Reference Signs List 10 image input device 11 scanner 12 digital still camera 14 video camera 20 image processing device 20a RGB conversion unit 20b color conversion unit 20c color correction unit 20d binarization unit 20e instruction unit 20f pattern sheet generation unit 20g correction curve generation unit 20h correction curve Storage unit 20i Display unit 21 Computer 23 Keyboard 24 CD-ROM drive 25 Floppy disk drive 26 Modem 27 Mouse 30 Image output device 31 Printer 32 Display

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Michina Osawa 3-3-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (reference) 2C262 AA02 AA24 AA26 AB11 BA09 BA20 BB03 BB36 BC01 BC10 EA04 EA12 FA13 5B057 AA11 CA01 CA08 CA12 CA16 CE17 5C077 LL12 LL19 MP08 PP32 PP37 PP74 TT05 5C079 HB01 HB02 HB03 LA02 LA12 LA23 LA31 LB01 MA10 NA03 NA05 NA27

Claims (11)

[Claims] 1. An image processing apparatus for adjusting a gray balance based on a pattern sheet and a correction curve output from an image output apparatus, comprising: a plurality of patches in which the amount of each element color is changed in each of a plurality of gradations Pattern sheet generating means for generating a pattern sheet having the following pattern, and outputting the generated pattern sheet to the image output device; and a plurality of patches for each gradation of the pattern sheet, achromatic patches are formed for each gradation. Patch selection means for selecting each, and correction curve generation means for generating a correction curve for each element color and an achromatic color correction curve based on the amount of change of the element color in the patch selected for each gradation by the patch selection means, Correction curve correction means for correcting the correction curve, and based on the correction curve correction, the pattern sheet The pattern sheet is regenerated by the generation unit and output to the image output device. From the plurality of patches for each gradation of the output regenerated pattern sheet, the achromatic patch is converted for each gradation by the patch selection unit. Select the image processing device. 2. The image processing apparatus according to claim 1, wherein the correction curve correction unit sets a control point at which a correction amount of the correction curve can be controlled, and the set control. An image processing apparatus comprising: a correction amount setting unit configured to set a correction amount of the correction curve at a point; and correcting the correction curve based on the set control point and the set correction amount. 3. The image processing apparatus according to claim 2, further comprising a display unit for displaying a correction curve generated by the correction curve generation unit, wherein the display unit displays the correction curve based on the displayed correction curve. An image processing apparatus, wherein a control point setting unit sets a control point, and the correction amount setting unit sets a correction amount of a correction curve. 4. The image processing apparatus according to claim 1, wherein the patch selection unit selects each gradation based on a correction curve corrected by the correction curve correction unit. An image processing apparatus further comprising: a unit that changes the amount of each component color of a patch and outputs the changed patch for each gradation to the image output device. 5. The image processing apparatus according to claim 1, further comprising a storage unit configured to store the correction curve corrected by the correction curve correction unit. 6. The image processing apparatus according to claim 1, wherein an amount of an element color to be changed by said pattern sheet generating means is changed according to a gradation. 7. The image processing apparatus according to claim 1, wherein an amount of an element color to be changed by said pattern sheet generation means is increased as the gradation becomes lower. 8. The image processing apparatus according to claim 1, wherein an amount of an element color to be changed by said pattern sheet generating means is different for each element color. 9. The image processing apparatus according to claim 1, further comprising: display means for displaying a pattern sheet generated by said pattern sheet generation means, wherein said patch selection means is provided. An image processing apparatus for selecting an achromatic patch for each gradation from a plurality of patches for each gradation of a displayed pattern sheet. 10. An image processing method for adjusting gray balance based on a pattern sheet and a correction curve output from an image output device, comprising: a plurality of patches in which an amount of each element color is changed in each of a plurality of gradations A pattern sheet generating step of generating a pattern sheet having the following pattern, and outputting the generated pattern sheet to the image output device; and a plurality of patches for each gradation of the pattern sheet. A patch selection step of selecting each, a correction curve generation step of generating a correction curve for each element color and an achromatic color correction curve based on the amount of change of the element color in the patch selected for each gradation in the patch selection step, A correction curve correcting step of correcting the correction curve, wherein the pattern sheet is corrected based on the correction curve. The pattern sheet is regenerated in the image generation device and output to the image output device. From the plurality of patches for each gradation of the output regenerated pattern sheet, an achromatic patch is generated for each gradation in the patch selection step. Select the image processing method. 11. A computer-readable recording medium having recorded thereon a program for causing a computer to execute image processing for adjusting gray balance based on a pattern sheet and a correction curve output from an image output device, comprising: Pattern sheet generation processing for generating a pattern sheet having a plurality of patches in which the amount of each element color is changed at each tone of a tone, and outputting the generated pattern sheet to the image output device; A patch selection process of selecting an achromatic patch for each tone from a plurality of patches for each tone, and a change amount of an element color in the patch selected for each tone by the patch selection process. A correction curve generation process for generating a correction curve and an achromatic correction curve; Based on the correction curve correction process to be corrected and the correction of the correction curve, the pattern sheet is regenerated by the pattern sheet generation process and output to the image output device, and each gradation of the output regenerated pattern sheet is output. And a computer-readable recording medium storing a program for causing a computer to execute an achromatic patch for each gradation from the plurality of patches by the patch selection process.