JP2000190572A - Method for processing image and print system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a color tone or gradation characteristic desired by a user in a print system for printing color images. SOLUTION: A plurality of hue samples are output for each base color of R, G and B from a printer 1 based on data not corrected in color balance in a base color-setting process 16 of a printer driver 10. A color balance table- correcting process 17 adjusts a correction parameter of a color balance- correcting table to be used in a color-correcting process 13 on the basis of the base color selected by the user. In a printing process after the color-adjusting process, the color balance is corrected on the basis of a color tone desired (selected) by the user.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing method and a printing system, and more particularly to adjustment of color and gradation characteristics in an image printed by a printing apparatus.

[0002]

2. Description of the Related Art Recently, colorization of OA equipment such as a color printer, a color scanner, and a color copy is becoming common. For example, a color inkjet printer is an apparatus that performs printing by discharging inks of different colors from a plurality of print heads on a print medium. Since this inkjet printer forms an image using relatively small ink droplets, a high-definition image comparable to a silver halide photograph can be obtained by appropriately selecting a printing method and a recording medium.

However, there are cases where the density characteristics of an output image change due to a change in the environment where the printer is installed or a change with time in the ink or the device itself. This change in output density characteristics
In the case of a single color printer, it only appears as a change in the density of the single color, but in a full color printer,
Appears as a change in color. For this reason, various proposals have conventionally been made to add a function for color adjustment (also referred to as "calibration") to a color printer so as to maintain the output density characteristics that the printer should originally target. ing.

For example, Japanese Patent Application Laid-Open No. 63-113568 discloses that memories of yellow, cyan, magenta (hereinafter abbreviated as Y, C and M) and black (hereinafter abbreviated as K) are stored in a memory in the apparatus. It is described that data of a density pattern expressed in gradation for each color is stored, and the density pattern is output as an image at the time of color adjustment. Then, the density of the output image is measured by density measuring means, and the density pattern data of the measurement result is compared with the stored density pattern data,
The color correction circuit for the image data is controlled so that they match.

Japanese Patent Application Laid-Open No. 4-77060 discloses that
Similarly, a gradation pattern serving as a reference for density is stored in a memory in the printer, the reference gradation pattern is output as an image at the time of color adjustment, and the gradation pattern is read by a sensor to read the reference gradation pattern. It is disclosed that a parameter of gamma correction is changed so that the density of an output image becomes appropriate as compared with a pattern.

FIG. 1 is a diagram conceptually showing the configuration of output density adjustment of the above-mentioned conventional example. During normal printing, the printer 1 uses a color correction parameter stored in the memory 2 to correct color and gradation of image data for print data sent from a host device such as a personal computer. A correction circuit 3 is provided.

The memory 4 previously stores color correction data in which the gradation of each color is expressed, and the memory 5 similarly stores each target density value in the gradation data of each color. It is stored first. At the time of color adjustment, the color adjustment data from the memory 4 is supplied directly to the print mechanism unit 7 without passing through the color correction circuit 3, and a predetermined adjustment image having a gradation according to the color adjustment data is printed on the paper. The density of the print result 8 is measured by the densitometer 9 to obtain a measured density value. Next, the measured density value is compared with the target density value from the memory 5 in the comparison circuit 6 in the printer 1, and based on the comparison output result, the density value measured by the densitometer 9 is stored in the memory 5. The color correction parameters in the memory 2 are rewritten so as to match the density values. Further, during normal printing, as described above, the image data is rewritten (adjusted) in the color correction circuit 3 as described above, and color correction or gradation correction is performed based on the color correction parameters from the memory 2. The corrected image data is supplied to the printer 7 and printed out.

The method of adjusting the color or density described above is as follows.
Some have been incorporated into products offered on the market. For example, in an electrophotographic full-color printer, a color patch according to a plurality of levels of density values is output for each of C, M, Y, and K when a developing toner is replaced.
It is read by the attached scanner and color adjustment of each color is performed. By performing this operation, it is possible to adjust a difference in color due to an individual difference of a toner to be used.

A typical conventionally known color adjustment method is a parameter adjustment in color correction called a masking method. Masking is, for example, four input colors Cin, Min, Yin, Ki of C, M, Y, K
n, is corrected by the following matrix operation expression, and the output color Co
The color is corrected by obtaining ut, Mout, Yout, and Kout.

[0010]

[Table 1]

The masking represented by the above equation has a linear input / output relationship since it consists of only the first-order terms for each input color. In this case, the gradation of each of the primary colors C, M, Y, and K is maintained. For example, in the case of blue (hereinafter, abbreviated as B) obtained by mixing C and M, The relationship between the density of B actually printed on the recording medium and the input is not linear due to differences in the printing mode, the amount of ink absorbed by the recording medium, and the reflectance (ground color of the recording medium). (Hereinafter abbreviated as R and G, respectively),
For the secondary color of blue (B), it is difficult to maintain the gradation by the color correction processing.

Therefore, for example, C, M, Y, R, G, B,
A table is provided for each of the seven colors of K, and in each table, output values of a predetermined color are respectively associated with all input values of the corresponding color of 0 color in 255 steps, and based on this table, Methods for performing color correction are also known.

[0013]

However, in the above-mentioned conventional printer for performing density correction or color correction,
The purpose of this printer is to perform density adjustment or color adjustment so as to maintain the target color tone gradation characteristics that should be set in advance. There is a problem that is difficult.

That is, in order to obtain the desired color and gradation characteristics of the printer from the user, it is necessary to perform color adjustment and gradation adjustment on the image in advance using image processing software or the like and then perform printing. Must. However, the image processing software is expensive and has very many functions, so that it is often difficult to use the image processing software to perform color conversion and density correction unless a technician specializing in image processing is used. The applications most commonly used in offices and homes are word processing, spreadsheet, and drawing software. Since the images created by these applications are configured in a format dedicated to them, they cannot be pasted on image processing software configured in a bitmap format, a TIF format, or the like. Therefore, color conversion and density correction of an image created by the application cannot be performed, and the color and gradation characteristics desired by the user cannot be obtained. Further, the color reproduction of the monitor is an additive color mixture, while the color reproduction of the printer is a subtractive color mixture. Therefore, it has been known that even if the user can set a desired color on the monitor, an image output by the printer may not be color-matched with the desired color.

In general, the color reproduction characteristics of printers provided on the market generally differ depending on the printer maker that provides the printer. For this reason, even if the same print data and the same recording medium are prepared and printed for the printers of each maker, the colors and contrasts which are considerably different depending on the printer maker are often received as an impression. A profile for color reproduction in each printer is defined in each printer driver for each print mode or recording medium type of the printer, or a ROM in the printer main body.
Etc., and it is not easy for the user to arbitrarily change it. In such a case, usually, when a user purchases a printer, he or she sees print samples of each printer and selects a printer that performs color reproduction that meets the user's preference.

[0016] The taste of the color and the gradation characteristics (contrast) of the image may differ depending on the national pattern or individual. For example, in Europe and the United States, tone reproduction with a strong contrast is preferred, and a vivid color tone close to a primary color is preferred.
Conversely, Asians prefer smooth tone reproduction and softer colors. From this point of view, it is desirable to be able to freely set the color tone that the user prefers for each color. You can only do it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image processing method and a printer capable of obtaining desired color and gradation characteristics desired by a user. It is to provide a system.

[0018]

According to the present invention, there is provided:
An image processing method for performing color adjustment of an image to be printed based on print data subjected to color correction by a printing apparatus, the method comprising: inputting color selection information by a user and printing characteristic information of the printing apparatus; The color adjustment is performed by changing the color correction parameter based on the selection information and the print characteristic information.

Preferably, the printing apparatus further comprises a step of printing a plurality of samples having different colors for a predetermined color based on the reference print data by the printing apparatus. The information is information on a color selected from the plurality of samples and information on a relationship between the color and the reference print data.

The printing apparatus may further comprise the step of printing a plurality of patches on the basis of gradation print data having a plurality of levels of densities for the predetermined color, wherein the densities of the plurality of printed patches are determined. It is characterized in that gradation information obtained by measurement is further input as the print characteristic information.

Further, in the image processing method, output gamma correction is further performed on the print data, and the printing device prints an output gamma correction gradation patch for the predetermined color, And changing the correction parameter of the output γ correction based on the gradation information obtained by measuring the density of the output γ correction gradation patch.

Further, the selection information is gradation information obtained by measuring a plurality of levels of density of a patch selected by the user from a plurality of color patches included in the printing apparatus, and the printing characteristic information is The gradation information is obtained by measuring the densities of a plurality of patches printed by the printing apparatus based on print data of a plurality of levels for the colors of the selected patches.

According to the above arrangement, since the correction parameters in the color correction are adjusted based on the color selection information by the user, the color correction after the color adjustment is performed based on the selected color. , And the image printed based on the color-corrected print data follows the color selected by the user. And in this case,
Since the adjustment is performed based on the print characteristics of the printing apparatus that performs the printing, it is possible to appropriately reflect the print data in consideration of the user's selection in the print result.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a block diagram showing the basic configuration of a typical print system known in the prior art. This print system has, for example, software of an application and a printer driver in a personal computer, and a printer. Note that the printer driver may be configured to perform the following processes in the printer. The configuration shown in FIG. 2 is obtained by extracting only a portion related to color matching, and the other processes are not shown.

In FIG. 2, an application 11 is a general application such as desktop publishing (DTP), image processing, and a word processor.
In the input correction 12, which is one process of the printer driver 10, the input gamma conversion for correcting the light emission characteristics of the CRT or the like with respect to the R, G, B luminance data and the converted luminance data are used for C, M used in the printer. , Y density data. Brightness and density have a logarithmic relationship,
Generally, logarithmic conversion is performed to convert to C, M, and Y densities. Similarly, the color correction unit 13, which is one process of the printer driver, generates black, corrects color balance,
Performs UCR processing. In the black generation, a black component is extracted from the Y, M, and C density data obtained by the input correction 12. Generally, of the three colors C, M, and Y, those having the minimum density value are replaced with black. Next, color balance correction performs color balance correction according to the color development characteristics of ink.
As described above, this method includes a masking method and C,
There is a method of performing color correction based on a color balance table such as M, Y, R, G, and B. In an embodiment described later, an example in which color balance correction is performed using a color balance table will be described.

FIG. 3 is a block diagram showing an example of a color balance table used in the color balance correction. As shown in FIG.
M, Y, R, G, B and K are composed of tables 131, 132, 133, 134, 135, 136 and 137, respectively.

C, M, Y tables 131, 132, 1
At 33, the corrected density values C ', M', and Y 'corresponding to the inputs of C, M, and Y are output. Also R,
In the G and B tables 134, 135 and 136, the corrected densities of (M, Y), (C, Y) and (C, M) forming the colors for the inputs of R, G and B, respectively. The values C ', M', Y 'are output. Table 13
4, 135, and 136 also output corrected density values C ', M', and Y ', which are complementary color components of the corresponding colors, respectively. The purpose is to increase the vividness of R, G, and B realized on the recording medium.

Furthermore, in the K table 137, the correction density values C ', M',
Y 'and K' are output.

Each of the input density values in the tables 131 to 137 described above is based on a set of (C, M, Y) obtained through the processing of the input correction 12, as described above with reference to FIG. Can be obtained as follows. First, K is generated by the above-described black generation processing, and then two of C, M, and Y that are not replaced by the black generation are replaced by R and R by the same replacement as the black generation.
Either G or B is generated.

For example, if the set of (C, M, Y) is M,
Assuming that the density value is smaller in the order of Y and C, first, the portion of M is replaced with K to generate black K, and the remaining (C, Y)
Is replaced by G formed by C and Y. From the above, one set of density data (C, M, Y) is decomposed into C, G, K density data (in this example, the density values of M, Y, R, B are 0).

C, which is decomposed and generated as described above,
The density data of M, Y, R, G, B, and K is input to each table shown in FIG. By generating K and R, G, B as described above, the correction values C ′, C ′,
Arbitrary output values can be set for M ', Y', and K ', whereby color adjustment processing can be easily performed.
Good color balance or color matching can be realized. Note that the C, M, and Y tables 13
At 1, 132, and 133, the output values set in the K, R, G, and B tables are set as described above.

FIG. 4 is a diagram conceptually showing, as an example, the R table 134 among the above-mentioned tables. In the figure, the horizontal axis is the input value, and the R concentration is 0 to 0.
255 indicates 256 values, while the vertical axis indicates the output value, and similarly indicates the density value for each of C ′, M ′, and Y ′. Note that this output value corresponds to the amount of ink droplets ejected by the recording head of the printer 1, and is not the density of the ink dots actually printed on the recording medium. In the case of R, since the color is formed from the mixed color of M and Y as described above, the output value corresponding to each value of M ′ and Y ′ from the minimum input value to the maximum input value of R is the color balance or the output value. It is set in consideration of color matching. Also,
As described above, a negative output value is set for C 'in order to increase the sharpness of R.

In general, the relationship between input and output is not linear as is apparent from the example shown in FIG. In other words, the ratios of the C, M, and Y driving amounts differ depending on the input values. This is because the amount of ink absorbed on the recording medium, its diffusivity, and the amount of reflected light vary depending on the amount of light applied. This characteristic also differs greatly depending on the recording medium.

FIG. 5 is a diagram conceptually showing a K table 137. By conversion using this table,
A so-called UCR is performed. Generally, UCR is a process of removing the portion replaced by black in black generation from the Y, M, and C color components. However, as shown in FIG. 5, all components of Y, M, and C are removed. I will not be hurt. That is, when the input density value of black is small, printing is performed using process black obtained by mixing colors of Y, M, and C so that black dots are not visually noticeable. Further, when black is generated with the process black of C, M, and Y as the input density value increases, the ink overflows on the recording medium, and the amount of Y, M, and C is gradually reduced. Reduce the amount of process black and increase the amount of black ink applied instead.

Referring again to FIG. 2, the processing γ correction 14 of the printer driver 10 is a processing for correcting the relationship between the density values actually realized on the recording medium and the input density values C, M, Y, K. . In general, even if the relationship between the colors (the ratio of each color) is corrected by the color balance correction, the input density and the density value actually realized on the recording medium for each color have a non-linear relationship as shown in FIG. In addition, saturation occurs at a low input level. This is because ink droplets ejected from the recording head diffuse on the recording medium and the density does not increase in proportion to the amount of ejection. Further, the relationship between the input density and the density on the recording medium varies depending on, for example, the type of recording medium relative to ink. For example, the above-described relationship is not uniquely determined because the ink absorptivity differs depending on the recording medium.

Further, in FIG. 2, the binarization 15 is a process of converting the C, M, and Y density data obtained as described above into binary data for ejecting / not ejecting ink in the printer. As the binarization processing, a known dither method or the difference diffusion method, which is a modification thereof, can be used. Then, the binarized data is transferred to the printer 1 via the interface, and printing is performed based on this data.

As shown in the basic configuration described above, the printing system described in the following embodiments not only performs a printing operation by a printer, but also prints the data by a printer from image processing by a printer driver. This shows the process up to and including the process. This is because, in recent years, the processing speed of the computer has improved, so that the input correction, which was conventionally processed by the hardware in the printer body,
This is because processing such as color correction output gamma correction and binarization has recently been performed by a printer driver. In other words, the processing of the printer system of the following embodiment starts from the point when a print request is made by the application and the print data is passed to the printer driver, and the processing from when the printer actually prints out. However, in such a print system, a form in which the above-described processing of the printer driver is executed by hardware or software in the printer is included in the print system of the present invention.

(First Embodiment) FIG. 7 is a diagram mainly showing a configuration of a printer driver according to a first embodiment of the present invention. The printer driver 10 of the present embodiment is obtained by adding a basic color selecting function and a function of modifying a color balance table according to the basic color selection to the basic configuration of the printer driver shown in FIG.

In FIG. 7, the basic color setting section 16 has a basic color selection sample. This basic color is a reference color when the contents of the table are corrected by the color balance table correcting unit 17. When the user requests to change the basic color, the basic color setting unit 16
Outputs the predetermined R, G, B sample print data directly to the printer 1 without performing color correction on the sample print data. In addition, from the basic color setting sample output by the printer 1, the basic color selected by the user is registered in a predetermined memory. The color balance table correction unit 17 corrects the color balance table of the default setting set for each print mode or recording medium in the printer driver in accordance with the basic colors obtained as described above. Then, a process of returning the table to the color correction unit 13 is performed.

In the present embodiment, only the correction of the color balance table is performed for color adjustment as described above. In the present embodiment, the recording medium used for printing is determined, and therefore, the correction parameters of the output γ correction 14, which are relatively greatly affected by the type of the recording medium, do not need to be corrected so much. Further, the input correction 12 is a part for performing the processing of the input γ correction and the luminance / density conversion, so that it is not necessary to modify this parameter so much.

Next, the procedure of the color correction parameter correction processing (color adjustment) based on the configuration shown in FIG. 7 will be described with reference to the flowchart shown in FIG.

When the user requests to change the setting of the basic color (step S101), the basic color setting unit 16 converts the Y, M, C, and K data for printing the basic color selection sample into color data. The data is sent to the printer 1 without correction, and the printer 1 prints a sample based on the data (step S102). Here, the basic colors that can be set are three colors of R, B, G, or R, G, B,
Six colors of C, M, and Y can be used. However, with the default settings, the basic color samples to be printed are R, G, B
Three colors. This is the primary color of C, M, Y
This is because it is more advantageous to use a single color ink in terms of the amount of ink absorbed on the recording medium.

FIG. 9 is a diagram showing an example of printing a sample for selecting a basic color. Here, it is assumed that there are three colors of R, G, and B. In the example shown in FIG. 9, a sample group of 5 × 5 is used for each color density, but any number of samples may be used as long as the number of samples is equal in the vertical and horizontal directions. In the sample group of each color, the center sample represents the hue set by default, and the other samples change the respective components of R, G, and B in the directions indicated by the arrows by the ratios specified in the boxes. It indicates that. For example, the sample in the upper right corner of each sample group of 5 × 5 has R and G of + 30% and G of −3 compared to the default (center sample) hue value.
It shows that each value is 0%. However, this ratio of 30% is only used as a default value, and the ratio can be freely set when the user requests printing of the basic color selection sample. The center default color is an output value when the input value is the maximum density of each color (255). That is, in the present embodiment, the hue is changed based on the density at the maximum value.

In the example shown in FIG. 9, the sample group is classified by each color of R, G and B.
The sample group B may be classified by region, country, age, gender, or the like, and may be selected. Note that such a classification can be performed with reference to statistical data and the like.

Referring again to FIG. 8, step S10
In 3, the user performs a process for selecting a basic color with reference to FIG. That is, the basic color setting unit 16
Display the user interface as shown in. The user moves the square box 181 horizontally and vertically by operating the arrow 18 to a position corresponding to the selected color to set the color selected by the sample via this display. I do. Next, in step S104, the printer driver 1
At 0, the basic color selected and set by the user is registered.

On the basis of the above basic color setting, in the next step S105, the color balance table correcting section 17
Corrects the above-described default color balance table of the color correction unit 13 according to the selected new basic color. The correction method is as follows. For example, with respect to the values of M 'and Y' obtained by inputting the selected R density values to the R default table 134 (see FIG. 3) of the color correction unit 13, the maximum input value of R in the table is obtained. If the output values of M 'and Y' with respect to (255) are 1.2 times and 0.8 times, respectively, all the outputs set in the R table 134 in accordance with the respective ratios. Make corrections by changing the values.

As described above, in the present embodiment, since the color correction is performed based on the maximum density, there is an advantage that the processing for that is simplified.

If there is no request from the user to set a basic color, a default color balance table is used (step S107).

According to the above procedure, the color balance table is corrected, and the corrected color balance table is sent to the color correction section 13, and the color balance correction table is determined based on the corrected color balance table (step S106).

By performing the above processing, the user can set his / her favorite color tone by setting the basic color without depending on the printer maker or model, and the color is adjusted according to the color. Can be printed by the printer.

(Second Embodiment) In the above-described first embodiment, the colors are matched based on the density at the time of maximum input, and the change rate of the existing table set as a default for the intermediate color is determined. Using. Therefore, the color at the time of the maximum input matches the basic color selected by the user, but the gradation characteristics of the intermediate color may not be corrected appropriately. The reason is that, as described above, the absorption amount, diffusion amount, and light reflection amount of the ink on the recording medium do not have a linear relationship between the ejection amount and the actually realized density. Therefore, in the present embodiment, color adjustment is performed so that the gradation characteristics of the intermediate color are also compensated.

FIG. 11 is a block diagram showing the configuration of a printer driver according to the second embodiment of the present invention. The difference from the configuration according to the first embodiment is that a tone patch generation unit 19, a densitometer 20 that reads the density of a patch printed based on the tone patch generation unit 19, and a color balance table in place of the color balance correction unit. The point is that a color balance table calculation unit 21 for calculation is added.

In FIG. 11, a densitometer 20 is used to measure the density of a print sample. Specifically, the density is measured using the following. A density sensor separately provided on a carriage on which a recording head and an ink tank are mounted, a scanner cartridge which can be used by being replaced with a recording head and mounted on the carriage, and a flatbed scanner, etc. However, for the density sensor or scanner cartridge built into the printer,
It is desirable to hold a profile for correcting these input characteristics on a printer driver or to read out from a file and calibrate the input / output characteristics. When a scanner such as a flatbed not specified by the manufacturer is used, it is desirable to use the scanner after calibrating its characteristics.

The gradation patch generation section 19 includes the basic color setting section 1
6, the tone patch data is generated based on the basic color set by the user according to the configuration described in the first embodiment. The maximum density of the gradation patch matches the density of the basic color set by the user. This is because the basic color is determined by the density at the maximum input value as described above. The color balance table calculation unit 21 performs a process of calculating a color balance table based on the measured tone patches and returning the table to the color correction unit. Here, the reason that the color adjustment is performed only by modifying the color balance table is for the same reason as described in the first embodiment.

Next, with reference to a flowchart shown in FIG. 12, a processing procedure of color adjustment according to the second embodiment of the present invention will be described.

Processing up to registration of the basic colors in the printer driver (steps S201 to S204) is performed in the same procedure as the processing described in the first embodiment. Again, R, G,
The procedure for performing color correction for the three colors B will be described. However, the procedure may be performed for the six colors C, M, Y, R, G, and B as described above.

Next, tone patch data is created based on the selected basic color, and the printer 1 prints the tone patch based on the tone patch data (step S205). That is, first, the tone patch generation unit 19 sends the tone patch data to the printer 1 without performing the color correction processing, and the printer 1 prints the patch based on the data. FIG. 13 shows an example of R for the patch.

The patch shown in FIG. 13 is composed of 64 gradations, and the input value of the first patch in the upper left corner is 0,
The 64th patch in the lower right corner is the output result at the maximum input value (255), and the input value changes by four steps in each patch.

Next, the density of the output patch is measured by the densitometer 20 (step S206). The color balance calculation unit 21 corrects the maximum density value combining the selected basic colors based on the user's basic color selection information obtained from the basic color setting unit 16 and the density measurement result, and executes the halftone gradation characteristics. Make corrections. FIG. 14 shows the concept of the correction method of the correction parameter.

FIG. 14 is a diagram for explaining the modification of the parameters in the R table 134 as an example. The horizontal axis shows the input value of R, and the vertical axis shows the R value actually printed on the recording medium and measured. Shows the concentration of The actual calculation shown below is performed for M and Y obtained by decomposing R,
R is shown for simplicity of explanation. Here, f (x) indicates the relationship between the input value generated by the gradation patch generation unit 19 and the density on the recording medium shown in FIG. However, the density value corresponding to the maximum input value matches the density of the basic color selected by the user. h (x) is f (x)
Shows the result of obtaining a target function for a straight line of y = x. In order to linearly correct the density of the intermediate color, the inverse function f (x) is obtained from the density curve f (x) measured from the gradation patch with respect to the straight line of y = x, and this is used as a new color balance table. It is clear from this figure that if used, the density of the print result based on the data corrected by the table becomes linear.

In this embodiment, the density coordinates of 64 points obtained as a result of measuring a gradation patch to reduce the calculation time are first converted into coordinates that are symmetrical with respect to a straight line of y = x. The inverse function h (x) is calculated by obtaining the approximate curve by interpolating the converted coordinates. That is, for the density (Xn, Yn) of the patch of a certain gradation, the coordinates (Yn, Xn) which are the target positions with respect to the straight line of y = x are obtained, and a process of obtaining an approximate curve from these coordinates is performed.

FIG. 15 shows an example in which the above-described R gradation patch is printed using the color balance table obtained by this processing. As is apparent from this result, the density of the color at the maximum input value matches that shown in FIG. 3, but the density of the halftone changes linearly unlike that shown in FIG. . Also, in the above description, an example in which the density of the recording medium is saturated at a low input level value has been described, but not all examples are necessarily such examples.
Regardless of the shape of the measured density curve, by performing the above-described inverse conversion process, a color balance table in which the intermediate colors are linearly corrected can be obtained, and the maximum density is selected by the user. Matches the base color. Calculate the color balance table by the above method,
It is determined (steps S207, S208).

If there is no request from the user to set a basic color, the default color balance table is used as in the first embodiment (step S20).
9).

The color balance table is corrected according to the above procedure, and this new color balance table is sent to the color correction section 13 as shown in FIG. 11, and the color balance is corrected based on the new color balance table.

According to the above-described embodiment, the user can set his / her favorite color by setting the basic color without depending on the printer maker and the model, and also compensates for intermediate gradation characteristics. Color printing can be performed.

(Third Embodiment) In a third embodiment of the present invention, a function of further adjusting the correction parameter of the output γ correction table to perform density adjustment or color adjustment in addition to the above-described second embodiment. Is added. Accordingly, even when a recording medium other than the recording medium designated by the printer maker or a new recording medium that is not registered in the printer driver is used, the color can be adjusted to a color desired by the user. That is, by adjusting the correction parameters of the output γ correction table, an appropriate γ correction table corresponding to the ink absorption characteristics of the recording medium used for printing or the like can be used to make the input / output relationship linear, for example.

FIG. 16 is a block diagram showing a configuration of a printer driver according to the third embodiment. The difference from the configuration of the second embodiment is that an output γ table calculation gradation patch generator 22 and an output γ calculator 23 whose functions will be described below are added.

Next, the procedure of color adjustment processing according to the third embodiment will be described with reference to the flowchart shown in FIG. The processing of this embodiment differs from the processing of the second embodiment described above in that an algorithm for calculating the correction parameters of the output γ correction table is added in the first half of the processing procedure.

When a basic color setting request is made by the user (step S301), first, the output γ table calculation gradation patch generation unit 22 performs color correction on the printer 1 with the color gradation patch data as shown in FIG. Is sent directly to the recording medium to be used for printing by the printer (step S302). The data of the color gradation patch shown in FIG. 18 is for printing the gradation patch with C, M, Y, and K single color inks. Then, it is read by the above-described densitometer 20, and then, based on the density data, an inverse function is obtained by the correction parameter calculation method described with reference to FIG. 14 for the second embodiment to obtain an output γ correction parameter. (Step S30
3). By performing this processing, for example, an output γ table adapted to a new recording medium can be obtained. That is, it is possible to realize a density having a linear relationship with the input value on the recording medium.

The subsequent color correction processing is the same as the processing described in the second embodiment, and a description thereof will be omitted. In the subsequent output γ correction, the correction can be performed using the output γ table obtained as described above.

In this embodiment, by adding the function of adjusting (calculating) the correction parameter of the output γ correction table as described above, a recording medium not specified by the manufacturer or a new recording medium not registered in the printer driver is added. , It is possible to perform color correction so as to achieve the color desired by the user.

(Fourth Embodiment) In a fourth embodiment of the present invention, a large number of color sample patches of basic colors are bundled with a printer in advance, and the user can select patches of his / her favorite color from among them. Make a choice. Then, using the sample of the desired color as a target patch, the density is measured, and the color is adjusted accordingly. According to this embodiment, as in the first to third embodiments described above, there is no need to perform an operation of printing a color patch and obtaining a desired color based on the color patch, and even a beginner can easily perform color adjustment. It can be carried out.

FIG. 19 is a block diagram showing a configuration of a printer driver according to the fourth embodiment of the present invention.

In FIG. 19, a color balance table calculation unit 24 for a designated color uses a correction parameter of the color balance table to change the density realized on the recording medium so as to match the density of the target patch selected by the user. Is adjusted (calculated), and the result of the calculation is reflected in the color balance table.

Next, with reference to a flowchart shown in FIG. 20, a processing procedure of color adjustment according to the fourth embodiment will be described.

First, a user selects a target patch having a desired color from among the color patches of the basic colors included in the printer. The basic colors of this target patch are three colors of R, G, B, or R, G, B,
The colors are C, M, and Y. As the target patch, for example, a patch having 64 gradations like the patch shown in FIG. 15 is used. In this embodiment, in order to perform color adjustment for all gradations from low density to high density, 64 gradations are used in the same manner as the gradation patches used in the second and third embodiments. It is. When the user sets the target patch on the densitometer 20, the present process is started, and the density of the target patch is read by the density sensor 20 (step S401). Next, a patch of the same basic color (for example, R) as the selected color patch is directly printed on the recording medium used for printing without performing color correction (step S402). The measurement is performed (step S403). Then, the correction parameters of the color balance table are calculated by the color balance table calculation unit 24 for the designated color based on these two measurement results (step S404). That is, the color on the recording medium used for printing is adjusted to a color balance table that performs color correction so as to match the color of the target patch selected by the user.

FIG. 21 shows an outline of the calculation method. The horizontal axis in FIG. 21 indicates the input density value as in FIG. 14, and the vertical axis indicates the density actually printed on the recording medium. Here, f (x) indicates the density when a color patch is output without performing color correction on the recording medium used for printing, while g (x) indicates the density of the target patch selected by the user. Shows the results of the measurement. And h (x)
Based on these f (x) and h (x), for the recording medium used for printing, what kind of correction parameters should be used to perform the printing to match the target color? 3 shows a color balance table. The calculation of h (x) is performed as follows.

(1) In f (x), it is assumed that the density of a certain input value i on a recording medium used for printing is f (x).

(2) In g (x), an input value n satisfying f (i) = g (n) is searched.

(3) The points (x
a, yb).

(4) The above (1) to (3) at all measurement points
Is performed.

(5) From the point group obtained in (4), an approximate curve h
Find (x).

The color balance table is corrected according to the above procedure, and the new color balance table is sent to the color correction section 13 (step S405). This allows
In subsequent printing processes, color balance correction can be performed based on the color balance table.

By executing the above processing procedure, the user can reproduce the same color tone as that of the target patch selected by the user on the recording medium to be printed. That is,
In the fourth embodiment, since a color sample patch is prepared, color correction can be easily performed as compared with the configuration for color adjustment of the first and second embodiments.

In the above description, a case has been described in which color adjustment is performed on an existing recording medium in the same manner as in the first and second embodiments, but adjustment of the output γ correction table is also performed in the same manner as in the third embodiment. This makes it possible to perform color correction to a color desired by the user even on a recording medium not specified by the manufacturer or a recording medium not registered in the printer driver.

<Other Embodiments> The present invention, as described above,
The present invention may be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, and the like) or may be applied to an apparatus including one device (for example, a copying machine and a facsimile machine).

Further, software for realizing the functions of the above-described embodiment is installed in an apparatus connected to the various devices or a computer in the system so as to operate the various devices so as to realize the functions of the above-described embodiment. The present invention also includes a program code supplied and executed by operating the various devices according to a stored program in a computer (CPU or MPU) of the system or apparatus.

In this case, the program code of the software implements the functions of the above-described embodiment. The program code itself and means for supplying the program code to the computer, for example, the program code The stored storage medium constitutes the present invention.

Examples of storage media for storing such program codes include a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, and CD-R.
An OM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer, or another program. Needless to say, the program code is included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with application software or the like.

Further, the supplied program code is stored in a memory provided in a function expansion board of the computer or a function expansion unit connected to the computer, and then stored in the function expansion board or the function storage unit based on the instruction of the program code. It is needless to say that the present invention includes a case where a provided CPU or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0093]

As described above, according to the present invention,
Since the correction parameters in the color correction are adjusted based on the color selection information by the user, the color correction after the color adjustment is performed based on the selected color.
The image printed based on the color-corrected print data is
The color is selected by the user. In this case, since the adjustment is performed based on the print characteristics of the printing apparatus that performs the printing, it is possible to appropriately reflect the print data in consideration of the user's selection in the print result.

As a result, it is possible to obtain a print result having a color desired by the user. Further, such a print result can be obtained regardless of the recording medium used.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a conventional example of a configuration for color adjustment.

FIG. 2 is a block diagram showing a basic configuration for image processing of a printer driver used in an embodiment of the present invention.

FIG. 3 is a diagram showing a table used for color balance correction in the printer driver.

FIG. 4 is a diagram conceptually showing a red (R) table among the above tables.

FIG. 5 is a diagram showing a black (K) table, that is, a concept of UCR processing, among the above tables.

FIG. 6 is a graph showing input / output characteristics of density for explaining output γ correction.

FIG. 7 is a block diagram illustrating a configuration of a printer driver for color adjustment according to the first embodiment of the present invention.

FIG. 8 is a flowchart illustrating a color adjustment process according to the first embodiment.

FIG. 9 is a diagram showing a print example of a basic color selection sample used in the first embodiment.

FIG. 10 is a diagram showing a display for selecting a basic color by a printer driver according to the first embodiment.

FIG. 11 is a block diagram illustrating a configuration of a printer driver for color adjustment according to a second embodiment of the present invention.

FIG. 12 is a flowchart illustrating a color adjustment process according to the second embodiment.

FIG. 13 is a diagram illustrating an output example of a gradation patch according to the second embodiment.

FIG. 14 is a diagram illustrating calculation of a color balance table according to the second embodiment.

FIG. 15 is a diagram illustrating an example of an output result obtained by performing correction based on the color adjustment according to the second embodiment.

FIG. 16 is a block diagram illustrating a configuration of a printer driver for color adjustment according to a third embodiment of the present invention.

FIG. 17 is a flowchart illustrating a color adjustment process according to the third embodiment.

FIG. 18 is a diagram showing gradation patch creation image data for adjusting an output γ correction table according to the third embodiment.

FIG. 19 is a block diagram illustrating a configuration of a printer driver for color adjustment processing according to a fourth embodiment of the present invention.

FIG. 20 is a flowchart illustrating a color adjustment process according to the fourth embodiment.

FIG. 21 is a diagram illustrating calculation of a color balance table according to the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 10 Printer driver 11 Application 12 Input correction part 13 Color correction part 14 Output gamma correction 15 Binarization 16 Basic color setting part 17 Color balance table correction part 19 Gradation patch generation part 20 Densitometer 21 Color balance table calculation part 22 Output gamma table calculation gradation patch generation unit 23 Output gamma calculation unit 24 Color balance table calculation unit for specified color

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/60 H04N 1/40 D 5C079 1/46 1/46 Z F-term (Reference) 2C056 EA06 EA11 EC75 EC76 EE03 2C087 AA15 AA16 AC07 BD35 BD36 CB13 2C262 AA02 AA24 AA26 AA27 AB17 AC02 AC03 BA10 BA18 BB03 BB23 BC01 BC03 FA13 GA02 5B021 LG07 LG08 LL05 NN23 5C077 LL19 MM27 MP08 NN03 PP15 PP32P03 PP03 PP15 PP32 P03 PP03 LA31 LB02 MA01 MA04 MA10 MA19 NA03 PA02 PA03

Claims (11)

[Claims] 1. An image processing method for performing color adjustment of an image printed based on print data that has been subjected to color correction by a printing apparatus, the information comprising color selection information by a user and printing characteristic information of the printing apparatus. And performing color adjustment by changing the color correction parameters based on the selection information and the print characteristic information. 2. The method according to claim 1, further comprising the step of printing a plurality of samples having different colors for a predetermined color based on the reference print data by the printing apparatus. 2. The image processing method according to claim 1, wherein the information is information on a color selected from a plurality of samples and information on a relationship between the color and the reference print data. 3. The reference print data is data for printing the maximum density of the predetermined color, and the plurality of samples having different colors are a sample to be printed based on the data for printing the maximum density. 3. The image processing method according to claim 2, comprising a sample and a sample having a different color. 4. The method according to claim 1, further comprising the step of printing a plurality of patches by the printing apparatus based on gradation print data having a plurality of levels of densities for the predetermined color,
4. The image processing method according to claim 2, wherein gradation information obtained by measuring densities of the plurality of printed patches is further input as the print characteristic information. 5. The image processing method according to claim 1, wherein the color correction is a color balance correction. 6. The image processing method according to claim 1, further comprising performing output γ correction on the print data, causing the printing device to print an output γ correction gradation patch for the predetermined color, and 6. The image processing according to claim 5, further comprising a step of changing a correction parameter of the output γ correction based on gradation information obtained by measuring a density of the output γ correction gradation patch. Method. 7. The selection information is gradation information obtained by measuring a plurality of levels of density of a patch selected by a user from a plurality of color patches bundled with the printing apparatus, and the printing characteristic information is And gradation information obtained by measuring densities of a plurality of patches printed by the printing apparatus based on print data of a plurality of levels of densities for the color of the selected patch.
The image processing method described in the above. 8. The method according to claim 1, wherein the predetermined color is red, green, and blue, or each of red, green, blue, cyan, yellow, and magenta. Image processing method. 9. The image processing method according to claim 2, wherein the plurality of samples having different colors for the predetermined color are printed by region, country, gender, or age. . 10. A printing system for performing color adjustment of an image to be printed based on print data subjected to color correction by a printing apparatus, wherein information on color selection by a user and printing characteristic information on the printing apparatus are input. A print system, comprising: input means; and color adjustment means for performing color adjustment by converting the color correction parameters based on the selection information and print characteristic information. 11. A storage medium storing an image processing program for performing color adjustment of an image printed based on print data subjected to color correction by a printing device in a manner readable by an information processing device, The image processing program inputs color selection information by a user and printing characteristic information of a printing apparatus, and performs color adjustment by converting the color correction parameter based on the selection information and the printing characteristic information. A storage medium characterized by the above-mentioned.