JP5104641B2 - Color adjustment method - Google Patents

Description

The present invention relates to a color adjustment how to adjust the color (print color) to the target color.

In order to reproduce the target color within the reproducible color reproduction range so that the print color and the target color are relatively well matched, it is generally necessary to print several hundred or more points.
In addition, expensive software is required to create an ICC profile, and expert knowledge is required to create and operate an ICC profile using the software.

  Furthermore, even when an ICC profile is created, there is a case where it is desired to match a specific color as accurately as possible with an accuracy of less than 1.5 in ΔE * ab with a small color difference, for example, a color indicated by a color sample from the designer. In the case of such color adjustment, the accuracy may not be sufficient if the generated ICC profile output is used as it is. Therefore, in order to specify the color more accurately, it is necessary to trial and error test printing and color measurement, but it is not efficient.

  Also, when customizing an inkjet printing system that can handle a large number of ink sets and media types, an ICC profile is created by printing and measuring a large number of points in order to accurately match a small number of specific colors. May not be efficient.

Furthermore, there are restrictions on the media size, printable range, shape, and the like, and it may take a lot of labor and labor to record a large number of points.
In the case described above, a relatively large number of cases where the overall colors are generally matched or the measurement and printing costs for color matching are not a problem has been conventionally considered, but a relatively small number without using an ICC profile. In printing, there were few considerations in terms of matching specific colors with high precision.

The following Patent Documents 1 to 3 have been proposed for such color adjustment.
JP 2002-190960 A JP 2005-167630 A JP 2006-157294 A

  Here, the color adjustment of Patent Document 1 is an example of a method of adjusting color data to be output. For this reason, although the system value RGB is specified, there is a problem that the specification of RGB and the target color is not clear.

  Further, the method of Patent Document 1 requires that an ICC profile has already been generated, and uses the ICC profile to create device-dependent patch data from a target color and perform processing. Therefore, there is a problem that the ICC profile cannot be used unless it already exists.

  In the methods of Patent Document 2 and Patent Document 3 described above, an ICC profile must already be generated, and device-dependent patch data is created from the target color using the ICC profile for processing. It is. Therefore, there is a problem that the ICC profile cannot be used unless it already exists.

  In addition, the methods of Patent Document 2 and Patent Document 3 described above require a large number of printings. However, there has been a problem that costs such as printing labor related to multipoint printing, media, ink cost, measurement time and measurement labor are not considered.

  In other words, the above-described patent documents or various conventional color adjustment methods cannot efficiently match a specific target color with a small number of color charts. Therefore, if the ink and media cannot be printed with many points because of their high cost, or if it is not desirable, or if man-hours are required for printing and colorimetry for reasons such as printing on a solid object, the print area and the number of colorimetric points are limited. As a result, there is a problem that the colors cannot be efficiently and accurately matched.

  Further, for example, in a printing system using ink jet, there is a problem that a specific color cannot be efficiently and accurately matched in a printer that uses ink and media customized.

  Further, the conventional method is based on the premise that an ICC profile exists, and there is no method that can be adjusted without trial and error even if the ICC profile is not created and there is no knowledge about ICC profile operation.

  The prior art is related to the use of an ICC profile. In order to create an ICC profile, the print area becomes an obstacle or the measurement is difficult, or a specific color is strictly determined without the ICC profile. The adjustment itself has not been regarded as a problem in the past.

The present invention has been made to solve the above problems, when the ICC profile has not been created, and to realize the color adjustment how capable of color matching by a reduced number of steps.

The present invention for solving the above-described problems is as follows.
(1) According to the first aspect of the present invention, input data for color search sampled including a boundary value whose input value is 0 or the maximum value from a combination of input values in the entire input color space of three colors is created. Then, after converting to print data for N colors (N is an integer of 3 or more), printing and colorimetry are performed to obtain color search colorimetric data, and a color sample indicating the search target color is measured. Alternatively, a target color is acquired by specifying a device-independent color value, and it is determined whether or not the target color is included in or within a color space configured by the color search colorimetric data. If it is determined that the pixel is a point on the sampled color search input data grid, it corresponds to a tetrahedron composed of four points satisfying the condition that the increment in the color direction of all three colors is 0 or adjacent. Consists of a set of colorimetric data for color search A small color space that is a combination including the target color is identified, and a range of input values corresponding to the specified small color space is subdivided to search for a small color space color Create input data, convert it to N-color print data, print a chart, measure the color of the printed chart, and calculate target color-corresponding input data corresponding to the target color In the color adjustment method, in the calculation of the target color corresponding input data, a partial color space composed of a set of colorimetric values corresponding to four adjacent points in the small color space color search input data. Of these, the target color can not be selected including the position of the target color, and the target is set in a partial color space composed of a set of colorimetric values corresponding to four points including non-adjacent points in the small color space color search input data When you can select the one that includes the color position Calculated interpolation coefficients at a triangular pyramid interpolation on the selected partial color space, and calculates the target color corresponding input data from the coordinate values on the input data and the corresponding interpolation coefficient, which is a color adjustment method characterized by.
(2) The invention described in claim 2 creates color search input data sampled including a boundary value whose input value is 0 or the maximum value from a combination of input values in the entire input color space of three colors. Then, after converting to print data for N colors (N is an integer of 3 or more), printing and colorimetry are performed to obtain color search colorimetric data, and a color sample indicating the search target color is measured. Alternatively, a target color is acquired by specifying a device-independent color value, and it is determined whether or not the target color is included in or within a color space configured by the color search colorimetric data. If it is determined that the pixel is a point on the sampled color search input data grid, it corresponds to a tetrahedron composed of four points satisfying the condition that the increment in the color direction of all three colors is 0 or adjacent. Consists of a set of colorimetric data for color search A small color space that is a combination including the target color is identified, and a range of input values corresponding to the specified small color space is subdivided to search for a small color space color Create input data, convert it to N-color print data, print a chart, measure the color of the printed chart, and calculate target color-corresponding input data corresponding to the target color In the color adjustment method, in the calculation of the target color corresponding input data, a partial color space composed of a set of colorimetric values corresponding to four adjacent points in the small color space color search input data. Of these, when a color that includes the position of the target color cannot be selected, the barycentric coordinates of the color coordinates of each of the partial color spaces that are composed of a set of colorimetric values corresponding to four adjacent points in the input data for color search in the small color space The position of the center of gravity A neighboring partial color space that is a combination that minimizes the color difference from the target color is selected, an estimation coefficient is obtained based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color, and the estimated coefficient The color adjustment method is characterized in that the target color corresponding input data is calculated from the coordinate value on the corresponding input data.

( 3 ) The invention described in claim 3 creates color search input data sampled from a combination of input values in the entire input color space of three colors including a boundary value in which any input value is 0 or the maximum value. Then, after converting to print data for N colors (N is an integer of 3 or more), printing and colorimetry are performed to obtain color search colorimetric data, and a color sample indicating the search target color is measured. Alternatively, a target color is acquired by specifying a device-independent color value, and it is determined whether or not the target color is included in or within a color space configured by the color search colorimetric data. If it is determined that the pixel is a point on the sampled color search input data grid, it corresponds to a tetrahedron composed of four points satisfying the condition that the increment in the color direction of all three colors is 0 or adjacent. A set of colorimetric data for color search. A small color space which is a combination including the target color is specified from among the color spaces (small color spaces) to be processed, and a range of input values corresponding to the specified small color space is subdivided to search for a small color space color Input data is created, converted to the N-color print data, a chart is printed, the color of the printed chart is measured, and the target color corresponding input data corresponding to the target color is obtained. calculated, in the determination, when it is determined not to be included, the a point on the input data grid color search sampled, satisfies all three colors in the color direction increment 0 or adjacent 4 Finding the barycentric position of the color coordinates of each set of colorimetric data for color search corresponding to a tetrahedron composed of points, the colorimetric data for color search that minimizes the color difference between the barycentric position and the target color Special feature is a small neighborhood color space Then, the input value range corresponding to the specified nearby small color space is subdivided to create input data for searching for the neighborhood small color space color, and after converting it to the print data of the N color, the chart is printed. A color adjustment method for performing colorimetry on the printed chart and calculating input data corresponding to a target color as target color-corresponding input data , wherein the small color space is calculated in calculating the target color-corresponding input data. Of the partial color space composed of a set of colorimetric values corresponding to four adjacent points in the color search input data or the adjacent small color space color search input data, the one including the position of the target color cannot be selected. The barycentric positions of the color coordinates of each of the partial color spaces composed of sets of colorimetric values corresponding to four adjacent points in the input data for color search of the small color space or the input data for color search of the neighborhood small color space Seeking Select a neighboring partial color space that is a combination that minimizes the color difference between the centroid position and the target color, and obtain an estimation coefficient based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color, The color adjustment method is characterized in that the target color corresponding input data is calculated from the coordinate value on the input data corresponding to the estimation coefficient .

( 4 ) The invention according to claim 4 is characterized in that, when the color adjustment is repeated with respect to a plurality of target colors, already obtained colorimetric data for color search is used. The color adjustment method according to any one of items 3 to 4 .

( 5 ) The invention according to claim 5 is the case where the color adjustment is repeated for a plurality of target colors, and the small color space color search input data or the adjacent small color whose color space has already been measured. When the target color is included in any of the partial color spaces configured by the set of colorimetric values corresponding to four adjacent points in the spatial color search input data, the small color space color search input data or conversion to print data of the vicinity of the small color space color search input data, printing, omitted colorimetric is the color adjustment method according to any one of claims 1 to 4, characterized in that .

( 6 ) In the invention described in claim 6, the entire color search input data sampled from the combination of the input values in the entire input color space of the three colors including the boundary value whose input value is 0 or the maximum value. Created and converted into print data for N colors (N is an integer equal to or greater than 3) and then printed to create an overall chart for color search, and a color sample indicating the target color for search is measured or non-equipped The target color is acquired by specifying a dependent color value, and the color search for the color search including the target color is performed for either a color sample printed matter indicating the target color or a display color generated from the device-independent color value A range on the entire chart is designated as the minimum and maximum values in each direction of the input color space of the three colors, and input data for partial color search is generated by sampling the range of input values specified based on the specification. A color space in which the color data for color search is obtained by converting the print data to N-color print data, measuring the print result, and acquiring the color search data for color search. Is determined to be included in the boundary or the boundary, and if it is determined to be included by the determination, it is a point on the sampled color search input data grid, and increments in the color direction of all three colors are included. A small color that is a combination including the target color in a color space (small color space) composed of a set of colorimetric data for color search corresponding to a tetrahedron composed of 0 or four points satisfying adjacent conditions A space is specified, the input value range corresponding to the specified small color space is subdivided to create small color space color search input data, converted to the N color print data, and then a chart is printed. , Color measurement of the printed chart A color adjustment method for calculating target color-corresponding input data, which is input data corresponding to a target color, in the calculation of the target color-corresponding input data, adjacent to the small color space color search input data. Among the partial color spaces constituted by the sets of colorimetric values corresponding to the four points, those including the position of the target color cannot be selected, and the non-adjacent points in the small color space color search input data are included. When a partial color space consisting of a set of colorimetric values corresponding to points can be selected that includes the position of the target color, an interpolation coefficient is obtained by triangular pyramid interpolation in the selected partial color space and corresponds to the interpolation coefficient The color adjustment method is characterized in that the target color corresponding input data is calculated from the coordinate values on the input data .

( 7 ) In the invention described in claim 7, the entire color search input data sampled from the combination of the input values in the entire input color space of the three colors including the boundary value where any one of the input values is 0 or the maximum value. Created and converted into print data for N colors (N is an integer equal to or greater than 3) and then printed to create an overall chart for color search, and a color sample indicating the target color for search is measured or non-equipped The target color is acquired by specifying a dependent color value, and the color search for the color search including the target color is performed for either a color sample printed matter indicating the target color or a display color generated from the device-independent color value A range on the entire chart is designated as the minimum and maximum values in each direction of the input color space of the three colors, and input data for partial color search is generated by sampling the range of input values specified based on the specification. A color space in which the color data for color search is obtained by converting the print data to N-color print data, measuring the print result, and acquiring the color search data for color search. Is determined to be included in the boundary or the boundary, and if it is determined to be included by the determination, it is a point on the sampled color search input data grid, and increments in the color direction of all three colors are included. A small color that is a combination including the target color in a color space (small color space) composed of a set of colorimetric data for color search corresponding to a tetrahedron composed of 0 or four points satisfying adjacent conditions A space is specified, the input value range corresponding to the specified small color space is subdivided to create small color space color search input data, converted to the N color print data, and then a chart is printed. , The colorimetry of the printed chart There, calculates a target color corresponding input data is input data corresponding to the target color, a color adjustment method, in the calculation of the target color corresponding input data, adjacent the small color space color search input in the data When a partial color space composed of a set of colorimetric values corresponding to four points cannot be selected including a target color position, it corresponds to four adjacent points in the small color space color search input data. Obtain the barycentric position of each color coordinate of the partial color space composed of the set of colorimetric values, select a neighboring partial color space that is a combination that minimizes the color difference between the barycentric position and the target color, and Obtaining an estimation coefficient based on the distance between the color data corresponding to each vertex of the color space and the target color, and calculating the target color corresponding input data from the coordinate value on the input data corresponding to the estimation coefficient; It is to that color adjustment method .

(8) The invention according to claim 8, when repeating the color adjustment for a plurality of target colors, using already entire chart color search outputted, in claim 6 or claim 7, characterized in It is the color adjustment method described.

( 9 ) The invention according to claim 9 is a case where the color adjustment is repeated for a plurality of target colors, and the color search color measurement data in the range on the specified color search overall chart is already present. if it is acquired, converted into print data in the input data for the partial color search, print, omitted colorimetric is the color adjustment method according to claim 6 or claim 7, characterized in that .

(10) invention of claim 10, wherein, in the case of repeating the color adjustment for a plurality of the target color, the target color is already colorimetry already the small color space color search input data in data if included it matches any of the partial color space composed of a set of colorimetric values corresponding to the four adjacent points, the conversion into print data input data for searching the small color space color, printing omitted colorimetric, it is a color adjustment method according to claim 6 or claim 7, characterized in.

According to the above invention, the following effects can be obtained.
In the present invention, since the target color is set as a device-independent value, color adjustment can be performed quantitatively.

  In the present invention, the ICC profile is not used, that is, it is not necessary to use the conversion of “device-independent data → device-dependent data” that the ICC profile has. For this reason, even when there is no ICC profile, when the user has no knowledge about ICC profile setting, when there is no ICC profile builder, even when the amount of printing and measurement required for ICC profile creation is not desirable, Applicable for color matching of specific target colors.

  In the invention of the present application, since the inclusion is determined by a (minimum color) solid composed of actual measurement points at the time of patch creation and the inside is subdivided and remeasured, the number of measurement points required is small with respect to accuracy. Is efficient.

Hereinafter, the effect in each claim is explained in full detail.
(1) The invention of the color adjustment method according to the first aspect is characterized in that processing for specifying an input value corresponding to a target color by anisotropic subdivision, reprinting, and actual measurement is performed. Here, a configuration in which the target color is specified by finely dividing and measuring from the lattice points that retain the characteristics is a feature of the present invention that has not existed before.

  It is determined whether the target color is inside the sample point group by the solid composed of the measured points, and if it is inside, it is specified within the four points on the input space, and then it is specified more finely, so it is near with few sample points Color can be printed efficiently, and color adjustment can be performed efficiently. In addition, since combinations of inputs are limited to three colors, in a printer with four or more colors, the degree of freedom of combinations of four or more colors is restricted, and adjustment can be performed in the same manner as with three colors. Therefore, when an ICC profile is not created, accurate color matching can be performed with a small number of man-hours.

And if it is included in four points in the coarse color search colorimetric space, interpolation is also performed for target colors that are outside the small color space due to the nonlinear characteristics of the color space when divided into small color spaces. Can be estimated. For this reason, it is possible to perform more accurate color matching.

(2) The invention of the color adjustment method according to the second aspect is characterized in that the process of specifying the input value corresponding to the target color by anisotropic subdivision, reprinting, and actual measurement is performed. Here, a configuration in which the target color is specified by finely dividing and measuring from the lattice points that retain the characteristics is a feature of the present invention that has not existed before.
It is determined whether the target color is inside the sample point group by the solid composed of the measured points, and if it is inside, it is specified within the four points on the input space, and then it is specified more finely, so it is near with few sample points Color can be printed efficiently, and color adjustment can be performed efficiently. In addition, since combinations of inputs are limited to three colors, in a printer with four or more colors, the degree of freedom of combinations of four or more colors is restricted, and adjustment can be performed in the same manner as with three colors. Therefore, when an ICC profile is not created, accurate color matching can be performed with a small number of man-hours.
Then, a neighboring partial color space that is a combination that minimizes the color difference between the barycentric position and the target color is selected, and an interpolation coefficient is obtained based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color. Since the target color corresponding input data is calculated from the coordinate value on the input data corresponding to the interpolation coefficient, input data corresponding to the approximate color can be stably obtained even when there is no partial color space including the target color. Can do. Since not only the combination closest to the target color is selected, but also whether the calculation is performed by using interpolation or non-interpolation estimation depending on whether it is within the color gamut or not, appropriate target color corresponding input data can be obtained.
(3) In the invention of the color adjustment method according to claim 3, in addition to the above (2), even when the target color is outside the sample point group, the target is obtained at the center of gravity obtained from the combination of the four color search colorimetric data. To determine the closeness to the color, if the target color is inside the gamut boundary, it is possible to find the target color in the nearby small color space and obtain a color that is closer to the target color Can do. Even when the target color is out of the color gamut, it can be adjusted to a closer color with a small color difference. Therefore, when an ICC profile is not created, accurate color matching can be performed with a small number of man-hours.

( 4 ) In the color adjustment method according to the fourth aspect of the present invention, when color adjustment is repeated for a plurality of target colors, the already obtained colorimetric data for color search is used to obtain these data. Therefore, the number of steps can be reduced and color adjustment can be performed.

( 5 ) In the color adjustment method of the invention described in claim 5, when the color adjustment is repeated for a plurality of target colors, the color space input color search input data or the color space having already been measured or the color space If the target color is included in any of the partial color spaces formed by a set of colorimetric values corresponding to the four adjacent points in the input data for searching for a small color space near the color space, Conversion of input data or input data for searching for a small color space in the vicinity to print data, printing of a chart, and colorimetry can be omitted, so that man-hours can be further reduced and color adjustment can be easily performed. Can do.

( 6 ) In the invention of the color adjustment method according to the sixth aspect , compared to the chart to be measured by the measuring instrument, the entire chart to be visually judged may be smaller than the aperture (about φ10 mm) of the measuring instrument. Many colors can be printed while reducing For this reason, it is possible to reduce the number of prints and measurement points of the chart to be measured without increasing the number of prints so much. Compared to (1) above, a qualitative process of visualizing the entire chart is included, but the purpose here is to narrow the range, and in the subsequent processes, the color is handled quantitatively. By specifying a range of colors that differ by about 10 due to color differences, for example, with the intention that the target color is included in the print of the input data for partial color search with a slight margin, excluding a clearly different hue range, for example. Yes. Therefore, when an ICC profile is not created, accurate color matching can be performed with a small number of man-hours.

And if it is included in four points in the coarse color search colorimetric space, interpolation is also performed for target colors that are outside the small color space due to the nonlinear characteristics of the color space when divided into small color spaces. Can be estimated. For this reason, it is possible to perform more accurate color matching.

( 7 ) In the invention of the color adjustment method according to the seventh aspect of the invention, compared to the chart to be measured by the measuring instrument, the overall chart to be visually judged may be smaller than the aperture (about φ10 mm) of the measuring instrument, so the printing area Many colors can be printed while reducing For this reason, it is possible to reduce the number of prints and measurement points of the chart to be measured without increasing the number of prints so much. Compared to (1) above, a qualitative process of visualizing the entire chart is included, but the purpose here is to narrow the range, and in the subsequent processes, the color is handled quantitatively. By specifying a range of colors that differ by about 10 due to color differences, for example, with the intention that the target color is included in the print of the input data for partial color search with a slight margin, excluding a clearly different hue range, for example. Yes. Therefore, when an ICC profile is not created, accurate color matching can be performed with a small number of man-hours. Then, a neighboring partial color space that is a combination that minimizes the color difference between the barycentric position and the target color is selected, and an interpolation coefficient is obtained based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color. Since the target color corresponding input data is calculated from the coordinate value on the input data corresponding to the interpolation coefficient, input data corresponding to the approximate color can be stably obtained even when there is no partial color space including the target color. Can do. Since not only the combination closest to the target color is selected, but also whether the calculation is performed by using interpolation or non-interpolation estimation depending on whether it is within the color gamut or not, appropriate target color corresponding input data can be obtained.

( 8 ) In the invention of the color adjustment method according to the eighth aspect , when color adjustment is repeated for a plurality of target colors, the color search color measurement data already acquired is used to acquire these data. Therefore, the number of steps can be reduced and color adjustment can be performed.

( 9 ) In the invention of the color adjustment method according to claim 9, when color adjustment is repeated for a plurality of target colors, color measurement for color search in a range on the specified color search overall chart If data has already been acquired, conversion of print data of partial color search input data to print data, chart printing, and colorimetry can be omitted, so man-hours are reduced and color adjustment is performed. be able to.

(10) In the invention of the color adjustment method according to claim 10, wherein, in the case of repeating the color adjustment for a plurality of target colors, the color space is already colorimetry already the small color space color search input data in data If the target color to one of the set at constituted partial color space of the colorimetric values corresponding to four adjacent points are included, the conversion of the print data of the input data for searching the small color space color Since the chart printing and the color measurement can be omitted, the number of steps can be further reduced and the color adjustment can be easily performed.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. First, a color adjustment method and a color adjustment apparatus that are embodiments of the present invention will be described.
[A] First embodiment:
FIG. 1 is a block diagram showing an overall configuration of a color adjustment system 100 including a color adjustment device used in the present embodiment.

Here, 10 is RGB chart data relating to the entire chart, and 20 is a chart printed based on RGB chart data subjected to predetermined processing.
101 is a control unit that controls each unit, 105 is a storage unit that stores various parameters and data being processed, 120 is RGB (red, green, blue) and CMY (cyan, magenta, yellow) color conversion or color separation. A color separation unit to be performed, 130 is a gradation conversion unit that performs gradation conversion to a predetermined number of gradations, 140 is a halftone processing unit that performs predetermined halftone processing, and 150 is a CMY printer that prints using CMY color materials, 160 Is a colorimetric unit for measuring the color of the chart, and 170 is a determination unit for determining from the colorimetric result.

  That is, in this embodiment, color adjustment using the CMY printer 150 will be described as a specific example. The input is RGB data. After color separation from RGB to CMY and gradation conversion for each of C, M, and Y colors, halftone processing is performed.

Hereinafter, the operation of the present embodiment will be described with reference to the flowchart of FIG. 2 and various explanatory diagrams of FIG.
(1) Chart data generation:
First, RGB chart data (hereinafter simply referred to as chart data) 10 for printing a chart obtained by dividing each input axis RGB direction into five is created (step S201 in FIG. 2). The RGB chart data corresponds to color search input data.

In this case, by preparing five types of charts having 5 × 5 patches in which R and G are changed in five steps, and changing them for B, a chart with five steps for each axis of RGB is obtained.
Here, chart data for a chart (see FIG. 4) of about 4 × 20 cm, in which the size of one patch as a necessary size for measurement is 0.8 × 0.8 cm, 5 columns × 25 rows added with some margins, is arranged. create.

  When R, G, and B are 8-bit input and 0 to 255, any combination of 0, 64, 128, 192, and 255 is taken as 5 divisions. Each axis includes end inputs 0, 255 to cover the entire color space composed of RGB inputs.

(2) Chart data processing:
Various image processing relating to conversion to print data such as color separation by the color separation unit 120, gradation conversion by the gradation conversion unit 130, and error diffusion by the halftone processing unit 140 for the chart data 10 as described above. (Step S202 in FIG. 2).

Here, in the color separation unit 120, as color separation from RGB to CMY,
C1 = 255-R, M1 = 255-G, Y1 = 255-B,
The conversion process is performed.

This is merely an example, and non-linear conversion from RGB to CMY may be used.
Further, as the gradation conversion in the gradation converting unit 130, for example, the lightness L * is constantly reduced in proportion to the signal value for each of the C1, M1, and Y1 axes (FIG. 3B), C1 → The conversion characteristic of C2 is set (FIG. 3 (a)).

  That is, conversion is performed so that the visual changes for the respective inputs of the signals C1, M1, and Y1 are equalized by gradation conversion. For example, for C1 (or M1, Y1), the change in brightness L * is set to be constant as shown in FIG. It should be noted that density or the like may be used instead of brightness.

  In addition, it is desirable that this curve be set again at the time of calibration when the printer characteristics fluctuate. The gradation conversion is adjusted for each color of C1, M1, and Y1 regardless of the combination of colors. For this reason, it is not necessary to measure the characteristics in combination, and the adjustment can be made in decimal points.

  Here, it is desirable to increase the number of bits of each color from, for example, 8 bits to 12 bits in order to prevent gradation jumps associated with nonlinear conversion. This gradation conversion can be realized by a known method.

The halftone processing in the halftone processing unit 140 is performed by error diffusion, dither processing, or the like. This halftone process can also be realized by a known method.
Here, by making the input of the three colors into the number of colors corresponding to the printer color space by color separation, the signal value corresponding to the target color can be uniquely specified by the RGB value. In the case of a CMYK printer, CMYK is selected under the appropriate rules from RGB, for example, the total amount of ink is within a predetermined amount, the graininess of K dots is not noticeable, and the color connection is smooth. Color separation to produce. Even when spot colors are included, preferable spot color separation conditions are set from RGB and color separation is performed accordingly.

  The input axis is RGB in this example, but it may be CMY. Since the color coordinates have three degrees of freedom, it is only necessary to select three independent colors as the input color space. The ink color (redundancy) necessary for actual printing is color-converted by color separation processing, whereby the correspondence between the printed color and the input color in the color gamut can be clearly determined.

(3) Printing / colorimetry:
As described above, after the RGB chart data 10 as the color search input data is processed, it is printed as the chart 20 by the CMY printer 150 (step S203 in FIG. 2).

  Then, after the printed chart 20 is dried and the color is stabilized, each of the 125 patches of the chart 20 is measured by the color measuring unit 160 (step S203 in FIG. 2). Here, 125 colorimetric results are stored as a set of colorimetric values corresponding to values in the input color space.

(4) Target color data setting:
A target color to be adjusted is measured to obtain a colorimetric value L * a * b *. Alternatively, the target color may be directly given as a numerical value.

That is, here, a color sample indicating the search target color is set as the target color by color measurement or device-independent color value designation (step S204 in FIG. 2).
(5) Judgment:
As described above, it is determined whether the target value set in (4) is within the 125-point search input data color space measured in (3) (step S205 in FIG. 2).

Here, specifically, it is sequentially determined whether or not the target color is included in a triangular pyramid color space (tetrahedron) composed of four lattice points adjacent to each other in colorimetric values.
Here, when each color axis of the input data for color search is divided into five equal parts, the lattice points are 5 × 5 × 5 = 125 points as shown in FIG. In this case, 4 × 4 × 4 = 64 cubes composed of adjacent lattice points.

Furthermore, here, there are six triangular pyramids (FIG. 5 (b)) that constitute each cube of FIG. 5 (a) (included in the cube) and are composed of four points.
Accordingly, the 125 patches in the chart of FIG. 4 can be classified into 64 × 6 = 384 combinations of four points (triangular pyramid).

That is, it is only necessary to determine whether or not the target color is included in the triangular pyramid formed by each combination.
There are a plurality of ways to make a triangular pyramid by taking four points from a cube. However, if the increments ΔR, ΔG, ΔB of the unit steps of the R, G, B input axes are expressed as Δ for convenience, the RGB color space If the point closest to the origin of (ΔR, ΔG, ΔB) = (0, 0, 0) and (Δ, Δ, Δ) is included, each axis increment is 0 or 4 points , And can be uniquely divided into six triangular pyramids (tetrahedrons) No. 1 to No. 6 (see FIG. 5).

  That is, there are 64 ways of taking P1 as the point closest to the origin in the input color space, and there are 384 combinations of 4 points, which are 6 combinations of NO.1 to No.6. By replacing the four values in the output space, that is, the colorimetric values, it is determined whether the target color is included in or on the surface of the output color space.

Here, whether or not the four points of the triangular pyramid are included is determined as follows.
(5-1) Determination (1):
Now, the point indicating the target color is represented by a three-dimensional vector Px, and the vertices of the triangular pyramid are represented by three-dimensional vectors P1, P2, P3 and P4.

  In addition, the elements of each three-dimensional vector are assumed to correspond to L *, a *, and b *, respectively, of the components 0, 1, and 2 of P (number). At this time, the 4 × 4 matrix M1 is configured as follows.

  If P1, P2, P3, and P4 are not on the same plane (YES in step S601 in FIG. 6), the following formula is calculated using rank M1 = 4 and the inverse matrix M1 ^ -1. In the present specification, M ^ -1 is represented as an inverse matrix.

At this time, a1, a2, a3, and a4 represent the proximity of the point Px to the points P1, P2, P3, and P4, respectively.
That is, by calculation (step S602 in FIG. 6), if all these coefficients are 0 or more and 1 or less, it is determined that the point Px indicating the target color is included within the triangular pyramid constituted by P1 to P4 lattice points. (YES in step S603 in FIG. 6, (A)).

Here, since any coefficient is allowed to be 0, the determination of whether or not the coefficient is included in the triangular pyramid (hereinafter referred to as “internal determination”) includes the case where Px exists on the surface.
On the other hand, if any of the coefficients has a negative value, it is determined that the point Px indicating the target color is not included in the triangular pyramid (NO in step S603 in FIG. 6, (B)).

If the four color regions P1 to P4 are on the same point, straight line, or plane, rank M1 ≦ 3.
That is, a matrix in which column vectors of P1, P2, P3, and P4 are defined side by side is defined as
P = (P1, P2, P3, P4),
When
It has the same meaning as rankP ≦ 2.

Further, a matrix obtained by adding Px as a column vector is PB = (P1, P2, P3, P4, Px).
From rankP ≦ 2,
rankPB ≦ 3,
It is.

  Here, when rankP = 2 (YES in step S604 in FIG. 6), when rankPB = 2 is not satisfied, Px is not on the plane, and therefore it is determined that the point Px indicating the target color is not included in the triangular pyramid. (NO in S605 in FIG. 6, (B)).

Further, when rank PB = 2 (YES in step S605 in FIG. 6), since the point Px indicating the target color is on the same plane, it is determined whether it is included within the triangular pyramid (triangle) as follows.
It is determined whether or not Px exists in a point group that is a triangle among ΔP1P2P3, ΔP1P2P4, ΔP1P3P4, and ΔP2P3P4, that is, in a point group that is different from three points.

  For example, when three different points are P1, P2, and P3, a matrix M2 of 3 rows and 3 columns is configured as follows.

  Further, a1, a2, and a3 are calculated using the inverse matrix M2 ^ -1 as follows (steps S606 and S607 in FIG. 6).

  At this time, a1, a2, and a3 represent the proximity of Px to points P1, P2, and P3, respectively, and if all of these coefficients are 0 or more and 1 or less, Px is inside the triangular pyramid constituted by P1 to P3 lattice points. (YES in step S608 in FIG. 6, (A)).

  Also here, since any coefficient is allowed to be 0, the internal determination includes the case where Px is on the side. On the other hand, if any of the coefficients has a negative value, it is determined that the coefficient is not included inside.

  If ΔP1P2P3 is determined and is not included (NO in step S608 in FIG. 6), it is sequentially determined whether Px exists in or on any of ΔP1P2P4, ΔP1P3P4, and ΔP2P3P4. (Steps S606 to S609 in FIG. 6).

If all triangles are selected and not included in any triangle, it is determined that they are not included in the interior (YES in step S608 in FIG. 6, (B)).
(5-2) Determination (2):
If determination is not possible under the above conditions (flowchart in FIG. 6) (NO in step S604 in FIG. 6), according to the flowchart in FIG. 7 as follows, when all of P1 to P4 are the same point (step S701 in FIG. 7) And YES), it is determined whether or not Px matches that point (step S707 in FIG. 7).

  Here, if they match, it is determined that they are contained within the triangular pyramid (YES in step S707 in FIG. 7, (A)). If they do not match, it is determined that they are not included within the triangular pyramid (NO in step S707 in FIG. 7, (B)).

  Here, when all of P1 to P4 are not the same point (NO in step S701 in FIG. 7), rank P = 1, and when rank PB = 1 is not on the straight line, it is determined not to be included in the inside. (NO in step S702 in FIG. 7, (B)).

  When all of P1 to P4 are not the same point (NO in step S701 in FIG. 7), rank P = 1, and if rank PB = 1, P1 to P4 are on the same straight line (step S702 in FIG. 7). YES), it is determined whether Px is included in the internal dividing point as follows.

  Here, the determination is sequentially made when Px is on the same straight line. In the case where two different points are P1 and P2, the matrix M3 of 2 rows and 2 columns is configured as follows.

  Then, a1 and a2 are calculated by the following equation using the inverse matrix M3 ^ -1 (steps S703 and S704 in FIG. 7).

  At this time, a1 and a2 represent the proximity of Px to the points P1 and P2, respectively, and if all these coefficients are 0 or more and 1 or less, it is determined that Px is included in the P1 to P2 lattice points (FIG. 7). YES in step S705, (A)).

  Again, since any coefficient of 0 is allowed, the internal determination includes the case where Px is on the side. On the other hand, if any coefficient is a negative value, it is determined that the coefficient is not included in the triangular pyramid (NO in step S705 in FIG. 7, YES in S706, (B)).

However, the determination is usually made by calculation using a 4 × 4 size matrix M. In the above case, the case where the inverse matrix of the four-point matrix M1 cannot be obtained is exceptional.
In any of the above determinations, it is determined whether the set is composed of four points or is on the surface. When it is determined that it is not inside or on the plane, the same determination is sequentially performed for each triangular pyramid to determine whether or not the target color Px is included, and if it is determined that the target color Px is included (FIGS. 6 and 7). (A)), the process proceeds to the next process (6).

  On the other hand, when it is not included in any triangular pyramid of all the combinations, it is determined that it is not in the color gamut (YES in step S706 in FIG. 7, (B)). In this case, the process (6) is skipped and the process proceeds to the next process (7).

(6) Small color space determination (further determination when determined to be inside in (5) above):
In the determination of (5) above, if it is determined that the point Px indicating the target color is within the color gamut of the colorimetric value color space (YES in S206 in FIG. 2, (A) in FIGS. 6 and 7), As in-gamut processing (S207 in FIG. 2), is there any effective color search colorimetric data that has already been subdivided, printed, and measured for the specified small color space composed of four points? Judgment).

  If valid color search colorimetric data exists, this valid color search colorimetric data is used to (7) out-of-gamut processing, (8) chart printing, and (9) chart colorimetry described later. Is omitted and the process proceeds to the following (10). On the other hand, if there is no effective color search colorimetric data, the subsequent processing is performed.

First, data is created by subdividing the inside of the input value range of the four combinations of input values (R, G, B) corresponding to the small color space.
That is, in this embodiment, re-division (second-stage division) is performed on the first division (first-stage division).

Here, each of the three color axes is divided into five. Depending on the printing / measurement cost and the estimation accuracy, the number of divisions when subdividing is not limited to five. For example, 3 is acceptable.
Here, for example, when dividing into five, the number of points in the input side small color space is 1 + 3 + 6 + 10 + 15 = 35 points (FIG. 8). Similarly, when dividing into three, the number of points in the input side small color space is 1 + 3 + 6 = 10 points.

In this embodiment, the surrounding color solid is designated by 4 points based on the result of measuring the 125 points as shown in FIG.
On the other hand, it is also conceivable to specify the surrounding color solid with a cube. In this case, the chart is created by dividing into RGB isotropic directions. This corresponds to measuring all points in FIG. Therefore, it is necessary to print and measure 5 × 5 × 5 = 125 points at the time of five divisions.

  According to the present embodiment, the number of measurements is 35 even if the division is performed with the same accuracy. That is, since the ratio is 35/125, the same division accuracy can be obtained with a score of about 1/4. This is because the range in which the target color exists is specified not by a cube but by a triangular pyramid. By not assigning patches to each color axis isotropically, that is, by subdividing them anisotropically. Therefore, a small number of measurement points can be used effectively.

  In addition, as a result of the above, since the inside of the triangular pyramid is divided by 5 × 5 × 5 → 5 × 5 × 5, if only the vicinity of the target color is considered, the accuracy equivalent to that of creating the chart by 17 × 17 × 17 division is obtained.

In the case of 17 divisions for each color, the order is the same level as the grid point data normally used as the ICC profile.
Software for generating an ICC profile (ICC profile builder) usually obtains lattice points of this order by estimation from hundreds of measurement data, but in this embodiment, verification is performed at these lattice point levels by actual measurement. An effect is obtained.

  Therefore, even if the printer characteristics and the data conversion processing (color separation, gradation conversion, halftone processing, etc.) characteristics given to the printer are not linear, the input value RGB for specifying the target color with high accuracy is specified. Color search colorimetric data can be obtained.

Then, after executing the process (6) (small color space determination), the process proceeds to the following process (8).
(7) Out-of-gamut processing:
When it is determined in the determination (5) that the colorimetric value color space is not present (NO in step S206 in FIG. 2), the following is performed.

  In this case, a message indicating that the colorimetric value color space is not within the color space may be displayed to confirm whether or not to continue. And when not continuing, it complete | finishes. In this way, quick processing is possible.

  Further, when it is determined to be continued by the continuation confirmation process, or when the continuation confirmation process is not performed, the following process is executed as the out-of-gamut process (step S208 in FIG. 2).

  Here, the centroid vector Pw of the triangular pyramid of the combination including the lattice points on the surface of the color gamut among the 384 combinations of the four points described above is obtained. The combination of input values includes 0 or 255. Alternatively, although it is redundant, it may be performed for 384 patterns.

Pw (i) = (P1 (i) + P2 (i) + P3 (i) + P4 (i)) / 4,
Here, i = 0, 1, and 2.
Next, a color difference ΔE * ab between the gravity center position Pw and the target color Px is calculated.

In other words, the distance between the centroid vector and the target color vector in the L * a * b * space. Assume that the subscripts are stored in correspondence with L *, a *, and b * in 0, 1 and 2, respectively.
At this time, the following ΔE * ab is calculated.

Of the 384 color differences ΔE * ab calculated here, the smallest combination is not the inside but the outside near the color gamut boundary, and is therefore referred to as the “neighboring small color space”.
A combination of four points on the input value (R, G, B) side corresponding to this neighborhood small color space is obtained. Then, chart data is created by subdividing the neighborhood small color space. Here, each color axis is divided into five. When divided into five, the number of points inside the input side small color space is 35 points as shown in FIG.

  In this embodiment, even for the target color determined to be out of gamut (NO in step S206 in FIG. 2), the neighborhood small color space is selected as out-of-gamut processing (step S208 in FIG. 2). As for the near colors, as a result of the subdivided color measurement of 35 points, more accurate adjustment is possible for the colors specified as the points inside the color gamut.

  The reason for this is that the color gamut often has an outwardly convex characteristic (see FIG. 9) in the subtractive color mixture space, so it is determined that the color gamut is out of the color gamut as indicated by a point X in a rough area (dashed line in FIG. 9). This is because even if it is subdivided, it may fall within the color gamut (the region between the broken line between the black circles and the solid line between the white circles in FIG. 9).

(8) Small color space chart printing:
Chart data created as a small color space is subjected to processing such as color separation, gradation conversion, and error diffusion, and is printed by the CMY printer 150 (steps S1001 to S1003 in FIG. 10 and steps S1101 to 1104 in FIG. 11). .

(9) Small color space chart colorimetry:
After the printed chart is dried and the color is stabilized, the colorimetric unit 160 performs colorimetry. (Step S1003 in FIG. 10 and Step S1104 in FIG. 11).

  The measured data is stored in association with the number in 384 ways. In this way, when another target color is specified, if the corresponding triangular pyramid obtained in the determination process (5) matches the stored combination, the printing and measuring operations can be omitted, and the adjustment cost can be reduced. Can be reduced.

(10) Calculation of input data corresponding to the target color:
A partial color space (measurement corresponding to four adjacent points in the input data for small color space color search or in the input data for color search in the vicinity small color space) constituted by a combination of four adjacent points of the chart data of 35 colors measured. It is determined whether or not the target color is included in a partial color space formed by a set of color values (step S1004 in FIG. 10 and step S1105 in FIG. 11). Details are shown in the flowchart of FIG.

  Here, since the small color space of 35 colors is a triangular pyramid divided into five color axes, there are four combinations of 1/6 of a cube divided into five color axes. That is, 384/6 = 64. For these 64 combinations, the point indicating the target color is Px, and the apexes of the triangular pyramid are variables P1, P2, P3, and P4 (step S1201 in FIG. 12).

In addition, it is assumed that L *, a *, and b * are stored corresponding to the subscripts 0, 1, and 2 of the variables P1 to P4, respectively.
Now, a 4 × 4 matrix M using the variables P1 to P4 is constructed as follows.

  Here, when P1, P2, P3, and P4 are not in the same plane, the following equation can be calculated using rank M11 = 4 and the inverse matrix M11 ^ -1.

  At this time, a1, a2, a3, and a4 represent the closeness of Px to the points P1, P2, P3, and P4, respectively, and it is determined whether or not they are inside the color space based on these coefficients (step S1202 in FIG. 12).

  Here, if all these coefficients are 0 or more and 1 or less, it is determined that Px is included in the triangular pyramid formed by the P1 to P4 lattice points as in the above description (in step S1203 in FIG. 12). YES).

  Since the coefficient allows any 0, the internal determination includes the case where Px exists on the surface. On the other hand, if any of the coefficients has a negative value, it is determined that the coefficient is not included in the inside (NO in step S1203 in FIG. 12), as described above.

If it is determined at this stage that it is inside (YES in step S1203 in FIG. 12), the input data ro, go, bo corresponding to the target color is calculated using the calculated coefficients a1-a4 as follows. Process like this.
Ro = a1 * P1 corresponding to r + a2 * P2 corresponding to r + a3 * P3 corresponding to r + a4 * P4 corresponding to r,
Go = corresponding to a1 * P1, g + corresponding to a2 * P2, g + corresponding to a3 * P3, g corresponding to a + * 4 * P4,
B = corresponding to b + a4 * P4 corresponding to b + a3 * P3 corresponding to b + a3 * P3 corresponding to b + a2 * P2 corresponding to bo = a1 * P1
As shown in FIG. 12, the estimated rgb value corresponding to the target color is calculated and displayed (steps S1207 and S1208 in FIG. 12).

When rank M1 ≦ 3, four color areas P1 to P4 exist on the same point, straight line, or plane.
That is, a matrix in which column vectors of P1, P2, P3, and P4 are defined side by side is defined as
P = (P1, P2, P3, P4),
Where rankP ≦ 2.

Further, a matrix obtained by adding Px as a column vector is PB = (P1, P2, P3, P4, Px). From rankP ≦ 2,
rankPB ≦ 3,
It is.

  In the case of rank P = 2, if rank PB = 2, it is on the plane, so it is determined whether or not Px exists inside or on the side of the triangle constituting ΔP1P2P3, ΔP1P2P4, ΔP1P3P4, ΔP2P3P4 ( Step S1203 in FIG. Here, when rankPB = 3, Px is not on the plane, so it is determined that it is not included inside (NO in step S1203 in FIG. 12).

  If Px is on the same plane, it is determined whether it is included (step 1203 in FIG. 12). Here, in the case where two different points are P1 and P2, if a matrix M2 of 3 rows and 3 columns is configured as follows,

  Here, the following equation can be calculated using the inverse matrix M2 ^ -1.

  At this time, a1, a2, and a3 represent the proximity of Px to the points P1, P2, and P3, respectively, and if all of these coefficients are 0 or more and 1 or less, Px is a P1 to P3 lattice point as described above. (Step S1203 in FIG. 12 is YES).

  Since the coefficient allows any 0, the internal determination includes the case where Px is on the side. On the other hand, if any of the coefficients has a negative value, it is determined that it is not included in the inside (NO in step S1203 in FIG. 12), as described above.

  If ΔP1P2P3 is determined and not included, it is sequentially determined whether or not Px exists in or on any of ΔP1P2P4, ΔP1P3P4, and ΔP2P3P4 (step S1203 in FIG. 12). If it is not included in any of them, it is determined that it is not included in the inside (NO in step S1203 in FIG. 12, YES in S1204).

When it is determined that it is inside (YES in step S1203 in FIG. 12), the calculated coefficients a1 to a3 are used (step S1207 in FIG. 12), and the input data ro, go, bo corresponding to the target color are obtained. Do as follows.
Ro = r value corresponding to a1 * P1 + r value corresponding to a2 * P2 + r value corresponding to a3 * P3,
Go = g value corresponding to a1 * P1 + g value corresponding to a2 * P2 + g value corresponding to a3 * P3,
B = b value corresponding to a1 * P1 + b value corresponding to a2 * P2 + b value corresponding to a3 * P3,
Is calculated and displayed (step S1208 in FIG. 12).

  In the case of rank P = 1, if rank PB = 1, since P1 to P4 are on the same straight line, it is determined whether Px is included in the internal dividing point (step S1203 in FIG. 12). When rankP2 = 2, since it is not on a straight line, it is determined that it is not included inside (NO in step S1203 in FIG. 12). When all of P1 to P4 are the same point, it is determined whether Px matches that point (step S1203 in FIG. 12).

  The determination is sequentially made when Px is on the same straight line. In the case where two different points are P1 and P2, the matrix M3 of 2 rows and 2 columns is configured as follows.

  The following equation can be calculated using the inverse matrix M3 ^ -1.

  At this time, a1 and a2 represent the proximity of Px to the points P1 and P2, respectively. If all of these coefficients are 0 or more and 1 or less, Px is included in the P1 to P2 lattice points as described above. (YES in step S1203 in FIG. 12). Since the coefficient allows any 0, the internal determination includes the case where Px is on the side. On the other hand, if any of the coefficients has a negative value, it is determined that it is not included in the inside (NO in step S1203 in FIG. 12), as described above.

If it is determined that it is inside (YES in step S1203 in FIG. 12), the calculated coefficients a1 and a2 are used (step S1207 in FIG. 12), and the input data ro, go, and bo corresponding to the target color are obtained. Ro = a value corresponding to a1 * P1 + r value corresponding to a2 * P2,
Go = g value corresponding to a1 * P1 + g value corresponding to a2 * P2,
B = b value corresponding to a1 * P1 + b value corresponding to a2 * P2,
Is calculated and displayed (step S1208 in FIG. 12).

  The remaining determination is when P1 to P4 are the same point. At this time, if Px matches this point, it is determined that it is included inside (YES in step S1203 in FIG. 12), and if it does not match, it is determined that it is not included (in step S1203 in FIG. 12). NO).

When it is determined that P1 to P4 match as the same point (YES in step S1203 in FIG. 12),
R = r value corresponding to P1
G = g value corresponding to P1
B value corresponding to bo = P1,
Is calculated and displayed (steps S1207 and S1208 in FIG. 12).

Note that in the above, the case where the inverse matrix of M1 consisting of four points cannot be obtained is exceptional, and the determination is made substantially by calculation using the matrix M of 4 × 4 size.
In any of the above determinations (steps S1201 and S1202 in FIG. 12), it is determined whether the set is composed of four points or is on the surface (steps S1203 and S1204 in FIG. 12).

  On the other hand, when it is not included in any triangular pyramid of all 64 combinations (NO in step S1203 in FIG. 12, YES in S1204), it is determined that it is not in the color gamut, and the process proceeds to that case.

First, the gravity center position Pw of 64 triangular pyramids is obtained (step S1205 in FIG. 12).
Pw (i) = (P1 (i) + P2 (i) + P3 (i) + P4 (i)) / 4,
Here, i = 0, 1, and 2.

  Next, a color difference ΔE * ab between the gravity center position Pw and the target color Px is calculated. Assume that the subscripts are stored in correspondence with L *, a *, and b * in 0, 1 and 2, respectively.

Of the 64 patterns calculated here, a combination of four points at which the color difference ΔE * ab between the gravity center position Pw and the target color Px is minimized is obtained (step S1205 in FIG. 12).
Subsequently, the distance between each of the four points and the target color is obtained as l1x, l2x, l3x, and l4x. As a function of these distances, the following weights ai and the like are used.

Here, as the estimation algorithm change setting, the default setting value is n = 4, but other positive integers may be set.
Using the coefficients a1 to a4 created in this way (step S1205 in FIG. 12), as shown below, input data ro, go, bo corresponding to the target color is calculated (estimated) (in FIG. 12). Step S1206).
Ro = r value corresponding to a1 * P1 + r value corresponding to a2 * P2 + r value corresponding to a3 * P3 + r value corresponding to a4 * P4,
Go = g value corresponding to a1 * P1 + g value corresponding to a2 * P2 + g value corresponding to a3 * P3 + g value corresponding to a4 * P4,
B = b value corresponding to a1 * P1 + b value corresponding to a2 * P2 + b value corresponding to a3 * P3 + b value corresponding to a4 * P4,
Here, since estimation is performed using a plurality of neighboring points (four points), the estimated value is more stable than the estimation from only the nearest point (one point).

(11) Adjustment for other target colors:
When making adjustments for other target colors, the above (4) to (11) are repeated. In this way, the chart data generation (1), chart data processing (2), and colorimetry / printing (3) processes can be omitted.

  In other words, when color adjustment is repeated for a plurality of target colors, the acquisition of these data can be omitted by using already obtained color measurement data for color search. Color adjustment can be performed.

  Further, in the case where color adjustment is repeated for a plurality of target colors, the adjacent four points in the input data for small color space color search whose color space has already been measured or in the input data for color search in the vicinity small color space If the target color is included in any of the partial color spaces configured by the set of colorimetric values corresponding to, to the print data of the small color space color search input data or the neighborhood small color space color search input data Conversion, chart printing, and colorimetry can be omitted, so that man-hours can be further reduced and color adjustment can be easily performed.

  It should be noted that when the ink set and media of the printer apparatus are changed, when the change with the passage of time is dealt with, or when the user desires, the process is performed from any one of (1) to (3).

  As described above, the number of vertices of the color search data surrounding the target color is 4, which is the smallest solid that surrounds the target color. For this reason, the four points on the input space corresponding to the four points in the color search data can be identified most efficiently. Therefore, internal points on the input space can also be sampled effectively. Obviously, it is obvious that the number of measurements can be reduced when accurately matching several specific color samples, but it is effective even when there are about 60 to 130 target colors.

For example,
-5x5x5-> 3x3x3: Divide 9x9x9 = 729 points with 125 points + 10 points x (target color number 60 points)
・ 5x5x5 → 5x5x5: Divide 17 x 17 x 17 = 4913 points with 125 points + 35 points x (136 target colors)
It is.

  In other words, in the present embodiment, it is necessary to determine inclusion (first determination) with a (minimum color) solid composed of measured points when creating a patch, and subdivide the inside as a second stage to perform remeasurement. The number of measurement points is small with respect to accuracy, and it is efficient. Therefore, the accuracy can be increased, and the man-hour can be greatly reduced as compared with the conventional method.

[B] Second embodiment:
For four or more colors, it is possible to select a combination of three colors and apply the above method. However, if conversion is performed from the three colors to the number of colors to be used at the time of printing, the three colors are printed. Since the combination of inputs is limited to the above, in a printer with four or more colors, the color adjustment including the combination of four or more colors can be adjusted in the same manner as with three colors.

  Block diagrams in this case are shown in FIGS. 13 (a) and 13 (b). Here, the control unit 101, the color measurement unit 160, the determination unit 170, and the like are omitted, and the basic processing portion is mainly shown.

  For example, as shown in FIG. 13A, in the case of a CMYK printer 150 ′ using four color materials of CMYK (cyan, magenta, yellow, and black), the color separation unit 120 performs CMY-CMYK conversion and K is set. To generate.

  In this case, for example, the total value of the ink amounts of all four colors is within a predetermined amount, the K dot granularity is not conspicuous, the color connection is smooth, and the like, and so on, from RGB to CMYK. Create an appropriate rule f.

C1 = fc (R, G, B),
M1 = fm (R, G, B),
Y1 = fy (R, G, B),
K1 = fk (R, G, B),
Then, based on this rule f, color separation is performed so as to generate CMYK from RGB.

Thus, in the CMYK four-color printer, the color adjustment including the combination of the four colors can be adjusted similarly to the three colors.
Further, for example, as shown in FIG. 13B, in the case of a CMYKVO printer 150 ″ using CMYKVO (cyan, magenta, yellow, black, violet, and orange) color materials including special colors, the color separation unit 120 is used. The CMY-CMYKVO conversion is inserted to generate a KVO.

  In this case, for example, if the total value of the ink amounts of all six colors is within a predetermined amount, the granularity of K, V, and O dots is not conspicuous, the color connection is smooth, and the like, Create an appropriate rule f from to CMYKVO.

C1 = fc (R, G, B),
M1 = fm (R, G, B),
Y1 = fy (R, G, B),
K1 = fk (R, G, B),
V1 = fv (R, G, B),
O1 = fo (R, G, B),
Based on this rule f, color separation is performed so as to generate CMYKVO from RGB.

As a result, in the CMYKVO six-color printer, the color adjustment including the combination of the six colors can be adjusted in the same manner as the three colors.
Although specific examples of 4-color and 6-color printers are shown here, the present embodiment can also be applied to printers of other colors and colors.

[C] Third embodiment:
In the third embodiment, the process (10) (“calculation of input data corresponding to the target color”) in the first embodiment is partially different from the first embodiment.

  In the first embodiment, when the target color is determined to be outside the color gamut of the small color space (NO in step S1203 in FIG. 12, YES in S1204), the nearest quadrangular pyramid is specified (step in FIG. 12). In step S1205, estimation by extrapolation is performed (step S1206 in FIG. 12), but the third embodiment is characterized by the following.

  The processing of the third embodiment is shown in FIG. Here, the same step number is attached | subjected to the part which corresponds in FIG. 12 of the process in a color gamut in 1st embodiment. That is, steps having the same number of x, such as step S120x in FIG. 12 and step S140x in FIG. 14, mean the same processing.

  Here, in FIG. 14 of the third embodiment, when it is determined that all the combinations are not within the color space (step S1404A in FIG. 14), a combination of four points including non-adjacent points is selected ( Step S1404B-1 in FIG. 14 determines whether it is inside the small color space of a combination of four points including non-adjacent points (step S1404B-2 in FIG. 14). For example, the process proceeds to interpolation (YES in step S1404B-3 in FIG. 14, S1407).

  This is the case where it is determined that the color gamut is in the first stage, and if it is determined that the color gamut is outside the color gamut in the small color space of the second stage, four points in the second stage are selected. This means that a different triangular pyramid is created and the process in the small color space is re-executed.

  That is, when the target color is determined to be out of the color gamut of the small color space (NO in step S1403 in FIG. 14 and YES in S1404), it is determined that the first rough 5 × 5 × 5 region is within the color gamut. In the case (steps S205 and S206 YES in FIG. 2) and in the case where it is determined that it is not within the color gamut (steps S205 and S206 NO in FIG. 2), the determination in the second-stage subdivision in this embodiment is performed. Change. For this reason, the determination results of the first stage in advance (steps S205 and S206 in FIG. 2) are stored in the storage unit 105 and the like, and the control unit 101 and the determination unit 170 are determined during the determination of the second stage. Refer to.

  If it is determined in the color gamut in the first stage determination, the coarse 5 × 5 × 5 4 points are determined to be in the color gamut. In contrast to the sampling of the entire color space, when the color space surrounded by the noted grid is made fine, there may be a case where a deviation from the linear color region occurs due to the nonlinearity of the color space.

  Here, in order to understand the explanation, it is considered on a plane (FIG. 15, P1P2P3). For example, the point B exists in a triangle surrounded by P1P2P3, but corresponds to a case where it is determined that the subdivided 5 × 5 × 5 region is out of the color gamut.

  In such a case, if at least three points of the internal points R1 and P1P3 are used, the point B is included inside. Therefore, it is considered that it corresponds to the color gamut in the determination at the second stage, and the color estimated value can be interpolated.

  That is, the point determined to be inside at a rough interval, that is, the point determined to be inside the triangle in the figure is always inside P1P2P3 except for the variation component of the print, so a new point inside (in this example, Interpolation is possible with the point R1) and the remaining two points (P1, P3 in this case).

  The same applies to a three-dimensional space, and at least the target color can be included within a triangular pyramid surrounded by any combination of three points P1 to P4 with respect to the target color and the internal point. Can interpolate values.

  Furthermore, depending on the target color, it is obvious that it is also possible to enclose with inner points (white circles in FIGS. 15 and 16) instead of using three points from P1 to P4 (black circles in FIGS. 15 and 16). . In the case of FIG. 16, the point B2 shows an example that can be surrounded by white dots inside R1, R2, and R3.

  The above is different from the normal processing of the color gamut determined to fall within the triangular pyramid (the processing of FIG. 12 of the first embodiment) when it is not determined that it is inside the second stage small color space ( In step S1404A in FIG. 14, the condition for the four points on the adjacent small color space is changed to four points including the points that are not adjacent (step S1404B-1 in FIG. 14). If the change is made in this way, the target color can be surrounded as a triangular pyramid by surrounding points even if it is determined that the color gamut is out of the color gamut in the second stage due to the nonlinear characteristics of the color gamut (steps in FIG. 14). Interpolation can be performed (YES in steps S1404B-2 and S1404B-3) (steps S1407 and S1408 in FIG. 14).

  Of course, there is a degree of freedom in selecting surrounding points that are not adjacent to each other, but from the viewpoint of interpolation accuracy, it is preferable to select four points so that the volume of the triangular pyramid by the four points surrounding the target color is minimized. preferable.

  Here, the volume of the triangular pyramid is obtained using the following determinant.

  In addition, the method described so far can be used to determine whether or not it is inside the four points. Compared to printing / measurement, the cost of data processing is not often a problem. Therefore, the combination of 35 to 4 points mechanically = 35C4 = 52360, and the volume surrounding the target color is narrowed down to find the volume. Is interpolated with a combination of four points giving a volume of. Of course, 64 adjacent combinations of four points determined before that may be excluded, and further narrowing conditions may be set in advance.

  If the result of the determination as described above does not determine that the color gamut is present, a tetrahedron with four neighboring points is identified (step S1405 in FIG. 14) and extrapolated, as in the first embodiment. Is executed (step S1406 in FIG. 14). In such a case, it is due to measurement variations or characteristic shifts.

  On the other hand, if it is determined that the first rough 5 × 5 × 5 region is out of the color gamut (NO in step S206 in FIG. 2), a new inside of the color gamut in the small color space (YES in step S1404B-3 in FIG. 14). If determined, color estimation is performed by interpolation as in the first embodiment (steps S1407 and S1408 in FIG. 14). On the other hand, when it is not determined that the color gamut is within the small color space, color estimation is performed by extrapolation as in the first embodiment.

[D] Fourth embodiment:
The fourth embodiment will be described below. Here, it demonstrates centering on the difference with the above 1st embodiment-3rd embodiment.

First, the following (D1) and (D2) are executed. The process up to this point is the same as the first to third embodiments. Thereafter, the operation after (D3) is the characteristic operation as the fourth embodiment.
(D1) As a first step with respect to the target value, a position is calculated in a coarse 5 × 5 × 5 region. A triangular pyramid area including four lattice points is specified.

(D2) A chart for re-dividing the identified area as the second stage is created, and image processing, printing, and drying are performed.
(D3) Measurement is performed. The four grid points that are common to the charts used in the above (D1) and (D2) are preferentially measured first, and the colorimetric values are checked.

(D4) The range of deviation is determined. When the deviation range is deviated from a predetermined value set in advance, the user is warned, and the entire characteristic or the characteristic of the small color space is remeasured.
(D5) If the range of deviation is within a predetermined value, the measurement is continued. At this time, the colorimetric values regarding the four grid points may be used to replace (update) the data of the corresponding grid points in the rough area.

In the fourth embodiment, if the colorimetric values are checked as described above, printer abnormalities such as a shift in printing characteristics of the printer, ink outage, and head clogging can be identified early.
Therefore, by checking the colorimetric values as described above when printing a predetermined number of sheets or when a predetermined time has elapsed, the cost required for print materials (both ink and paper) and test time compared to conventional methods. Can be reduced.

[E] Fifth embodiment:
[A] As a modification of the first embodiment, the same processing can be executed by the following procedures a1 to h. Here, b2 is a determination by the determiner, and other processing is executed by the control unit.

a: The entire color search input data sampled including the boundary value whose input value is 0 or the maximum value from the combination of the input values in the entire input color space of the three colors is generated, and N colors (N is Create an overall chart for color search by printing after converting it to print data (integer of 3 or more),
b1: Obtain a target color by measuring a color sample indicating the target color of the search or specifying a color value independent of the device;
b2: For any one of the color sample printed matter indicating the target color or the display color generated from the device-independent color value, the range on the entire color search chart including the target color is the three colors Input color space is specified as the minimum and maximum values in each direction,
b2: a range on the entire color search chart including the target color when the judgment person visually observes the display color generated from the color sample printed matter indicating the target color or the device-independent color value Are specified as the minimum and maximum values in each direction of the input color space of the three colors,
b3: Partial color search input data obtained by sampling a range of input values specified based on the specification is generated, converted into print data for N colors, printed, and the print result is measured for color search. Get colorimetric data,
c: determining whether or not the target color is included in or within a color space formed by the color search colorimetric data;
d: When determined to be included by the determination, the sample is a point on the sampled color search input data grid, and is composed of four points in which the increment in the color direction of all three colors satisfies 0 or an adjacent condition. Identifying a small color space that is a combination including the target color from among a color space (small color space) composed of a set of colorimetric data for color search corresponding to a tetrahedron,
e: Subtracting the range of input values corresponding to the specified small color space to create input data for small color space color search;
f: Print the chart after converting to the N color print data,
g: Measure the color of the printed chart,
h: Calculate target color corresponding input data which is input data corresponding to the target color.

That is, this embodiment is characterized in that the determiner visually determines the entire color search chart.
By executing the color adjustment process including the determination by the determiner as described above, the entire chart visually determined by the determiner is compared to the chart to be measured by the measuring instrument. Since it may be smaller than that, a large number of colors can be printed while reducing the printing area. For this reason, it is possible to reduce the number of prints and measurement points of the chart to be measured without increasing the number of prints so much. Compared to (1) above, a qualitative process of visualizing the entire chart is included, but the purpose here is to narrow the range, and in the subsequent processes, the color is handled quantitatively. By designating in a range of colors that differ by about 10 due to color difference, it is considered that the target color is included in the print of partial color search input data with a slight margin. Therefore, when an ICC profile is not created, accurate color matching can be performed with a small number of man-hours.

[F] Sixth embodiment:
Moreover, [B] 2nd embodiment-[D] 4th embodiment can be combined as an application example with respect to [A] 1st embodiment, The above [E] 5th embodiment is combined. On the other hand, the above [B] second embodiment to [D] fourth embodiment can be combined as an application example. In this case, a synergistic effect with the effects obtained in the second to fourth embodiments can be obtained based on the effects obtained in the fifth embodiment.

It is a block diagram which shows schematic structure of embodiment of this invention. It is a flowchart which shows operation | movement of embodiment of this invention. It is explanatory drawing explaining embodiment of this invention. It is explanatory drawing explaining the chart of embodiment of this invention. It is explanatory drawing explaining embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. It is explanatory drawing explaining embodiment of this invention. It is explanatory drawing explaining embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. It is a block diagram which shows schematic structure of embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. It is explanatory drawing explaining embodiment of this invention. It is explanatory drawing explaining embodiment of this invention.

Explanation of symbols

10 RGB chart data 20 Chart 100 Color adjustment device 101 Control unit 120 Color separation unit 130 Gradation conversion unit 140 Halftone processing unit 150 CMY printer 150 ”CMYKVO printer 160 Color measurement unit 170 Determination unit

Claims (10)

Color search input data sampled from a combination of input values in the entire input color space of three colors including a boundary value where any one of the input values is 0 or the maximum value is generated, and N colors (N is 3 or more) After converting to print data (integer), print and measure the color to obtain the color search data for color search,
Acquire the target color by measuring the color sample indicating the target color of the search or specifying the device independent color value,
Determining whether the target color is included in or within a color space constituted by the color search colorimetric data;
If determined to be included by the determination, it is a point on the sampled color search input data grid, and is composed of four points where the increment in the color direction of all three colors satisfies 0 or an adjacent condition. Among the color spaces (small color spaces) configured by the color search colorimetric data set corresponding to the tetrahedron, specify a small color space that is a combination including the target color,
The input value range corresponding to the specified small color space is subdivided to create small color space color search input data, converted into the N color print data, printed a chart, and the printed Measure the color of the chart,
Calculating target color corresponding input data corresponding to the target color;
A color adjustment method,
In calculating the target color corresponding input data,
Among the partial color spaces formed by sets of colorimetric values corresponding to four adjacent points in the input data for color search in the small color space, those that include the position of the target color cannot be selected, and the small color space When it is possible to select a partial color space composed of a set of colorimetric values corresponding to four points including non-adjacent points in the color search input data including the target color position,
Find the interpolation coefficient by triangular pyramid interpolation in the selected partial color space,
The target color corresponding input data is calculated from the coordinate value on the input data corresponding to the interpolation coefficient.
A color adjustment method characterized by the above. Color search input data sampled from a combination of input values in the entire input color space of three colors including a boundary value where any one of the input values is 0 or the maximum value is generated, and N colors (N is 3 or more) After converting to print data (integer), print and measure the color to obtain the color search data for color search,
Acquire the target color by measuring the color sample indicating the target color of the search or specifying the device independent color value,
Determining whether the target color is included in or within a color space constituted by the color search colorimetric data;
If determined to be included by the determination, it is a point on the sampled color search input data grid, and is composed of four points where the increment in the color direction of all three colors satisfies 0 or an adjacent condition. Among the color spaces (small color spaces) configured by the color search colorimetric data set corresponding to the tetrahedron, specify a small color space that is a combination including the target color,
The input value range corresponding to the specified small color space is subdivided to create small color space color search input data, converted into the N color print data, printed a chart, and the printed Measure the color of the chart,
Calculating target color corresponding input data corresponding to the target color;
A color adjustment method,
In calculating the target color corresponding input data,
When it is not possible to select a partial color space composed of a set of colorimetric values corresponding to four adjacent points in the small color space color search input data including the target color position,
Obtaining a barycentric position of color coordinates of each partial color space constituted by a set of colorimetric values corresponding to four adjacent points in the small color space color search input data;
Select a neighborhood partial color space that is a combination that minimizes the color difference between the barycentric position and the target color,
Obtaining an estimation coefficient based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color;
The target color corresponding input data is calculated from the coordinate value on the input data corresponding to the estimation coefficient,
A color adjustment method characterized by the above . Color search input data sampled from a combination of input values in the entire input color space of three colors including a boundary value where any one of the input values is 0 or the maximum value is generated, and N colors (N is 3 or more) After converting to print data (integer), print and measure the color to obtain the color search data for color search,
Acquire the target color by measuring the color sample indicating the target color of the search or specifying the device independent color value,
Determining whether the target color is included in or within a color space constituted by the color search colorimetric data;
If determined to be included by the determination, it is a point on the sampled color search input data grid, and is composed of four points where the increment in the color direction of all three colors satisfies 0 or an adjacent condition. A color space (small color space) composed of a set of colorimetric data for color search corresponding to a tetrahedron is specified, and a small color space that is a combination including the target color is specified, and the specified small color space is Subtract the corresponding input value range to create small color space color search input data, print the chart after converting it to the N color print data, and perform the color measurement of the printed chart, Calculate the target color corresponding input data that is the input data corresponding to the target color,
If it is determined in the above determination that it is not included, it is a point on the sampled color search input data grid, and is composed of 4 points where the increment in the color direction of all three colors satisfies 0 or an adjacent condition. The color search colorimetric data set corresponding to the tetrahedron to be obtained is a set of colorimetric data for color search that obtains the barycentric position of each color coordinate of the set of colorimetric data for color search corresponding to the tetrahedron and minimizes the color difference between the barycentric position and the target color The neighborhood small color space is specified, the range of input values corresponding to the specified neighborhood small color space is subdivided, and input data for searching for the neighborhood small color space color is created and converted to the N-color print data Print the chart later, measure the color of the printed chart, and calculate the input data corresponding to the target color as the input data corresponding to the target color.
A color adjustment method,
In calculating the target color corresponding input data,
Includes the position of the target color in the partial color space composed of a set of colorimetric values corresponding to four adjacent points in the small color space color search input data or the adjacent small color space color search input data When you ca n’t select
The barycentric position of the color coordinates of each partial color space constituted by a set of colorimetric values corresponding to four adjacent points in the small color space color search input data or the adjacent small color space color search input data is obtained. ,
Select a neighborhood partial color space that is a combination that minimizes the color difference between the barycentric position and the target color,
Obtaining an estimation coefficient based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color;
The target color corresponding input data is calculated from the coordinate value on the input data corresponding to the estimation coefficient,
A color adjustment method characterized by the above . When the color adjustment is repeated for a plurality of target colors, color measurement colorimetric data already acquired is used.
The color adjustment method according to any one of claims 1 to 3 , wherein the color adjustment method is performed. In the case where the color adjustment is repeated for a plurality of target colors, the adjacent 4 in the small color space color search input data or the adjacent small color space color search input data whose color space has already been measured. When the target color is included in any of the partial color spaces configured by the set of colorimetric values corresponding to the points, the small color space color search input data or the adjacent small color space color search input data Omit conversion to print data, printing, colorimetry,
Color adjustment method according to any one of claims 1 to 4, characterized in that. Create input data for whole color search sampled from combinations of input values in the entire input color space of three colors, including any boundary value whose input value is 0 or the maximum value, and N colors (N is 3 or more) ) To print data, and then print to create an overall chart for color search,
Acquire the target color by measuring the color sample indicating the target color of the search or specifying the device independent color value,
For any one of the color sample printed matter indicating the target color or the display color generated from the device-independent color value, the range on the entire color search chart including the target color is the input color of the three colors Specified as minimum and maximum values in each direction of space,
Partial color search input data obtained by sampling a range of input values specified based on the specification is generated, converted into print data for N colors, printed, and the print result is measured for color search color measurement. Get the data,
Determining whether the target color is included in or within a color space constituted by the color search colorimetric data;
If determined to be included by the determination, it is a point on the sampled color search input data grid, and the four sides are configured with four points satisfying the condition that the increment in the color direction of all three colors is 0 or adjacent Specifying a small color space that is a combination including the target color from among a color space (small color space) composed of a set of colorimetric data for color search corresponding to the body,
The input value range corresponding to the specified small color space is subdivided to create small color space color search input data, converted into the N color print data, printed a chart, and the printed Measure the color of the chart,
Calculating target color corresponding input data corresponding to the target color;
A color adjustment method,
In calculating the target color corresponding input data,
Among the partial color spaces formed by sets of colorimetric values corresponding to four adjacent points in the input data for color search in the small color space, those that include the position of the target color cannot be selected, and the small color space When it is possible to select a partial color space composed of a set of colorimetric values corresponding to four points including non-adjacent points in the color search input data including the target color position,
Find the interpolation coefficient by triangular pyramid interpolation in the selected partial color space,
The target color corresponding input data is calculated from the coordinate value on the input data corresponding to the interpolation coefficient,
A color adjustment method characterized by the above. Create input data for whole color search sampled from combinations of input values in the entire input color space of three colors, including any boundary value whose input value is 0 or the maximum value, and N colors (N is 3 or more) ) To print data, and then print to create an overall chart for color search,
Acquire the target color by measuring the color sample indicating the target color of the search or specifying the device independent color value,
For any one of the color sample printed matter indicating the target color or the display color generated from the device-independent color value, the range on the entire color search chart including the target color is the input color of the three colors Specified as minimum and maximum values in each direction of space,
Partial color search input data obtained by sampling a range of input values specified based on the specification is generated, converted into print data for N colors, printed, and the print result is measured for color search color measurement. Get the data,
Determining whether the target color is included in or within a color space constituted by the color search colorimetric data;
If determined to be included by the determination, it is a point on the sampled color search input data grid, and the four sides are configured with four points satisfying the condition that the increment in the color direction of all three colors is 0 or adjacent Specifying a small color space that is a combination including the target color from among a color space (small color space) composed of a set of colorimetric data for color search corresponding to the body,
The input value range corresponding to the specified small color space is subdivided to create small color space color search input data, converted into the N color print data, printed a chart, and the printed Measure the color of the chart,
Calculating target color corresponding input data corresponding to the target color;
A color adjustment method,
In calculating the target color corresponding input data,
The small color space color when the color space including the target color position cannot be selected from the partial color spaces composed of sets of colorimetric values corresponding to four adjacent points in the small color space color search input data. Obtaining the barycentric position of the color coordinates of each of the partial color spaces composed of sets of colorimetric values corresponding to four adjacent points in the search input data;
Select a neighborhood partial color space that is a combination that minimizes the color difference between the centroid position and the target color,
Obtaining an estimation coefficient based on the distance between the color data corresponding to each vertex of the neighboring partial color space and the target color;
The target color corresponding input data is calculated from the coordinate value on the input data corresponding to the estimation coefficient,
A color adjustment method characterized by the above. When repeating the color adjustment for a plurality of target colors, use the already output overall chart for color search,
The color adjustment method according to claim 6 or 7 , wherein the color adjustment method is performed. When the color adjustment is repeated for a plurality of target colors, and the color search color measurement data in the range on the specified color search overall chart has already been acquired, the partial color Omit conversion, printing, and colorimetry of search input data to print data,
The color adjustment method according to claim 6 or 7 , wherein the color adjustment method is performed. In a case where for a plurality of said target color repeats the color adjustment, the colorimetric values of the target color is already corresponding to the adjacent four points of the colorimetric already the small color space color search input data in data if included it matches any of the set at constituted partial color space is omitted the conversion to print data input data for searching the small color space color printing, color measurement,
The color adjustment method according to claim 6 or 7 , wherein the color adjustment method is performed.