JP5850227B2 - Control device and program - Google Patents

Description

The present invention relates to a technique for correcting a color conversion table.

  For example, in Patent Document 1, color patches of a plurality of colors are measured in order to correct the correspondence between input color data in an image input device and output color data in an image output device. When the difference between the colorimetric value of the newly measured color patch and the colorimetric value of the color patch previously measured and stored in the image processing apparatus exceeds a predetermined threshold value, The colorimetric values of the newly measured color patch are stored in the past history storage unit. In other words, the colorimetric value of the color patch newly measured by the change in printer characteristics is stored in the past history storage unit. A printer profile is generated according to the colorimetric values stored in the past history storage unit.

JP 2004-147171 A

  However, in the configuration of Patent Document 1, the color patches of the same plurality of colors are always measured. For this reason, colors that are not required by the user may be measured. The present invention has been made to solve the above-described problems, and an object thereof is to provide a technique capable of determining an appropriate color to be measured.

  To achieve this object, the first apparatus of the present invention converts a color value expressed in the first color space into a color value expressed in the second color space. A first acquisition means for acquiring a first colorimetric value corresponding to a color expressed using a specific value of the second color space included in the color conversion table. Determining means for determining a plurality of values expressed in the second color space based on the specific value and the amount of change depending on the lightness of the first colorimetric value; A second acquisition unit that acquires a plurality of second colorimetric values obtained from a plurality of colors expressed using the value of the color, and the color conversion table using the plurality of second colorimetric values. Correction means for correcting the value of the specific color contained therein.

  With this configuration, it is possible to appropriately determine values for expressing a plurality of colors to be measured based on the specific value and the amount of change depending on the lightness of the first colorimetric value. . Since a plurality of colors to be measured are determined depending on the lightness of the first colorimetric value, the colorimetric values are not acquired in the vicinity of the specific lightness.

  Further, in the above apparatus, a first storage means for storing a target colorimetric value to be obtained from a color expressed using the specific value, the target colorimetric value, and the first colorimetric value And calculating means for calculating the color difference, wherein the correction means corrects the specific value of the color conversion table when the color difference is equal to or greater than the specific color difference.

  With this configuration, when the color difference between the target colorimetric value and the first colorimetric value is equal to or greater than a specific color difference, the correction unit can correct the color conversion table. In this way, for example, when the color difference between the target colorimetric value and the first colorimetric value is less than a specific color difference, a configuration in which a plurality of colorimetric values are not acquired can be achieved, and therefore wasteful colorimetry Can be suppressed from being executed.

  Further, in the above apparatus, the correction means uses the value for expressing a color corresponding to a specific colorimetric value selected from the plurality of colorimetric values, and specifies the specific color conversion table. It is preferable to correct the value of.

  With this configuration, a specific color can be corrected with a value for expressing a color corresponding to the acquired colorimetric value, so that the color conversion table can be corrected more appropriately.

  In the above apparatus, it is preferable that the amount of change is determined based on at least three color components constituting the specific value.

  With this configuration, since the change amount can be determined based on at least three color components, a plurality of values can be determined based on a more appropriate change amount.

  In the above apparatus, it is preferable that the determining unit further includes a correcting unit that corrects the amount of change based on a black component constituting the specific value.

  With this configuration, the amount of change can be corrected based on the black component, and thus a plurality of values can be determined more appropriately.

  Further, in the above apparatus, a correspondence table configured by a plurality of sets in which values expressed in the second color space correspond to amounts of change with respect to values expressed in the second color space. The correspondence table further includes a first change amount with respect to the first value expressed in the second color space, and a lightness greater than the first value. A second change amount relative to a second value, wherein the second change amount is smaller than the first change amount, and the determining means refers to the correspondence table, It is preferable to determine a plurality of values expressed in the second color space.

  With this configuration, it is possible to determine a plurality of colors to be newly measured based on the correspondence table, so that the processing load can be reduced.

  In the above apparatus, it is preferable that at least three color components constituting each of the plurality of values have the same value.

  The present invention can be realized in various modes such as a control device, a method executed by the control device, a computer program for realizing the function of the method or device, a recording medium on which the computer program is recorded, and the like. it can.

The block diagram which shows schematic structure of a terminal device. The figure which shows the information memorize | stored in a table. 5 is a flowchart showing color conversion table correction processing. The figure which shows the table based on a color patch. The figure which shows the relationship between a target value and a colorimetric value. The figure which shows UI regarding the determination result of a color difference. 6 is a flowchart showing color patch determination processing. The flowchart which shows change amount determination processing. The figure which shows the calculation method of the parameter used by the variation | change_quantity determination process. The figure which shows the determination method of the color patch newly output. The figure which shows correction of a color conversion table. The figure which shows a variation | change_quantity corresponding | compatible table.

Hereinafter, embodiments of the present invention will be described in the following order.
A. Example:
A-1. Terminal device configuration:
A-2. Overview of color conversion table correction processing:
A-3. Color conversion table correction processing:
B. Variation:

A. Example:
A-1. Terminal device configuration:
FIG. 1 is a block diagram illustrating a schematic configuration of a terminal device 10 according to the present embodiment.

  The terminal device 10 of the present embodiment includes a control unit 20, a display unit 21, an operation unit 22, and an interface 23, which are connected by a bus line.

  The control unit 20 includes a CPU 30 and a memory 40. The memory 40 stores a color conversion program 41 and a table 42. When the CPU 30 executes processing according to the color conversion program 41, the functions of the units 51 to 58 are realized. The table 42 includes a color conversion table 42a, a target table 42b, and a first colorimetry table 42c.

The terminal device 10 is connected to an external device such as the printer 70 and the colorimeter 80 via the interface 23. In this embodiment, the printer 70 outputs (prints) a plurality of color patches. The output (printed) color patch is measured by the colorimeter 80. In this embodiment, the colorimetric values of the color patches are expressed as L ^* a ^* b ^* values.

The control unit 20 receives the colorimetric result of the colorimetric color patch expressed in the L ^* a ^* b ^* space from the colorimeter 80 and stores it in the memory 40. The colorimetric value 43a measured by the colorimeter 80 has been described as being transmitted directly from the colorimeter 80 to the terminal device 10, but instead is transmitted from the colorimeter 80 to the printer 70. Alternatively, it may be transmitted to the terminal device 10 via the printer 70.

Here, the L ^* a ^* b ^* space means a CIEL ^* a ^* b ^* color space, and is a space in which colors are expressed without depending on various devices. Of the components constituting each value of the L ^* a ^* b ^* space, a * and b * are indices indicating hue and saturation, and L * is an index indicating lightness.

  The display unit 21 includes a display and displays various screens. The operation unit 22 includes a keyboard and a pointing device. The user selects items displayed on the display unit 21 by operating the operation unit 22.

  FIG. 2 is a diagram showing two tables 42 a and 42 b stored in the table 42 in the memory 40.

  FIG. 2A shows the color conversion table 42a. The color conversion table 42a includes coordinate values (R (n), G (n), B (n)) in the RGB space and coordinate values (C1 (n), M1 (n), Y1 (n) in the CMYK space. ), K1 (n)), and a table composed of a plurality of sets in a one-to-one correspondence. RGB represents red, green, and blue, respectively, and CMYK represents cyan, magenta, yellow, and black, respectively. The greater the value of each color component of RGB, the greater the lightness (in other words, the lower the density). On the other hand, the greater the value of each color component of CMYK, the smaller the brightness (in other words, the greater the density). The color conversion table 42 a is used when printing data is printed by the printer 70.

FIG. 2B shows the target table 42b. The target table 42b includes coordinate values (R (n), G (n), B (n)) in the RGB space, and L ^* a ^* b ^* values (L1 ( n), a1 (n), b1 (n)), and a table composed of a plurality of sets in a one-to-one correspondence. Each RGB value included in the target table 42b and each RGB value included in the color conversion table 42a are the same value.

A-2. Overview of color conversion table correction processing:
Next, the outline of the correction process of the color conversion table 42a executed in the present embodiment will be described. In the correction process of the color conversion table 42a, first, the printer 70 outputs a plurality of color patches. Thereafter, the color conversion table 42a is corrected based on the colorimetric values of the plurality of color patches. Specifically, the correction processing of the color conversion table 42a is performed by the color measurement L ^* measured by the color patch expressed by one CMYK value (CMYK value corresponding to one RGB value in the color conversion table 42a) ^. a ^* b ^* values, so as to approach the target ^L * ^a * ^{b *} values for the one of the RGB values in the target table 42b, is a process for correcting a color conversion table 42a. In the present embodiment, the color conversion table 42a is corrected for colors (colors in the gray axis direction) in which the values of the components of the RGB values are all the same.

In this embodiment, when the color difference ΔE between the target L ^* a ^* b ^* value and the colorimetric L ^* a ^* b ^* value is greater than or equal to a predetermined value, the control unit 20 performs the above-described color conversion table correction process. Execute. By doing this, the RGB value having a large color difference between the target L ^* a ^* b ^* value and the colorimetric L ^* a ^* b ^* value (that is, the color difference from the target L ^* a ^* b ^* value to be measured is changed). Color patches can be output within the threshold value (RGB values for which the colorimetric L ^* a ^* b ^* values do not exist).

A-3. Color conversion table correction processing:
FIG. 3 is a flowchart showing correction processing of the color conversion table.

  The color conversion table correction process is started, for example, when the user operates the operation unit 62 to give an instruction to correct the color conversion table 42a.

  The control unit 20 acquires the first color measurement table 42c based on the first color conversion table 42a (S50). Specifically, the control unit 20 causes the printer 70 to output color patches expressed by a plurality of CMYK values corresponding to a plurality of predetermined RGB values in the color conversion table 42a. The control unit 20 acquires the colorimetric value of the output color patch from the colorimeter 80 and stores it in the memory 40 as the first colorimetric table 42c.

The control unit 20 associates a plurality of predetermined RGB values of the color conversion table 42a with L ^* a ^* b ^* values corresponding to the RGB values, so that the plurality of RGB values are based on the color conversion table 42a. The printer 70 outputs a color patch expressed by a plurality of CMYK values corresponding to each. In the present embodiment, the plurality of predetermined RGB values are RGB values that satisfy the following expressions.

  (R (N), G (N), B (N)) = (0 + 16 × (N−1), 0 + 16 × (N−1), 0 + 16 × (N−1)) (1)

  (However, N is an integer satisfying 1 ≦ N ≦ 17. However, since the RGB value is expressed by 256 gradations, the RGB value having the highest brightness is (R, G, B) = (255, 255, 255). ) Is used)

  FIG. 4 is a diagram showing two tables 42c and 42d created based on the colorimetric values measured from the color patches.

  The control unit 20 acquires the colorimetric value of the output color patch from the colorimeter 80. 4A is generated based on the colorimetric values acquired from the output color patches (that is, the colorimetric values acquired before the color conversion table correction process is executed). The first colorimetric table 42c.

As shown in the drawing, the first color measurement table 42c is composed of a plurality of sets in which CMYK values are associated with L ^* a ^* b ^* values measured from the CMYK values.

A method for obtaining each colorimetric L ^* a ^* b ^* value of the first colorimetry table 42c will be described. The control unit 20 refers to the color conversion table 42a, so that CMYK values (FIG. 2) corresponding to a plurality of RGB values ((R (n), G (n), B (n)) in FIG. 2A). 2 (A) (C1 (n), M1 (n), Y1 (n), K1 (n))) is determined, and information indicating the CMYK value is transmitted to the printer 70.

The printer 70 receives the transmitted information indicating a plurality of CMYK values, and outputs a color patch on a sheet based on the CMYK values. The colorimeter 80 measures the L ^* a ^* b ^* value of the output color patch.

When the colorimetric L ^* a ^* b ^* values are acquired, the colorimeter 80 transmits the colorimetric L ^* a ^* b ^* values to the terminal device 10. As a result, the control unit 20 refers to the transmitted colorimetric L ^* a ^* b ^* values to determine the above-described RGB values ((Rn (0), Gn (0), Bn (in FIG. 2A)). 0))) and L ^* a ^* b ^* values ((Ln (1), an (1), bn (1)) in FIG. 3A) can be associated with each other. Instead of this, a configuration may be adopted in which information on predetermined colorimetric values is acquired from an external device other than the printer 70.

The control unit 20 generates a first color measurement table 42c shown in FIG. 4A based on each transmitted color measurement L ^* a ^* b ^* value and stores it in the table 42 in the memory 40.

In FIG. 3, the control unit 20 includes each target L ^* a ^* b ^* value of the target table 42 b stored in the memory 40 and each colorimetric L ^* a ^* b ^* value of the first colorimetric table 42 c described above. Are read (S100).

5, each target ^L * ^a * ^{b *} values of the target table 42a, each colorimetric ^L * ^a * ^{b *} values and, in correspondence to ^L * ^a * ^{b *} space of the first color measurement table 42c It is the figure shown in.

The target line TL is a line connecting points of the target L ^* a ^* b ^* values of the target table 42b. The adjustment line AL is a line connecting points of the respective colorimetric L ^* a ^* b ^* values in the first colorimetric table 42c. The larger the distance between two L ^* a ^* b ^* values for the same RGB value (ie, the color difference ΔE between the two points), the greater the color shift.

The color difference indicates a Euclidean distance between two points in the L ^* a ^* b ^* space. The target L ^* a ^* b ^* value for one RGB value is (L1 (n), a1 (n), b1 (n)), and the colorimetric L ^* a ^* b ^* value for the one RGB value is (L2 When (n), a2 (n), b2 (n)), the color difference ΔE is calculated by the following equation.

ΔE = sqrt {(L1 (n) −L2 (n)) ² + (a1 (n) −a2 (n)) ² + (b1 (n) −b2 (n)) ² } Expression (2)

The control unit 20, and the target ^L * ^a * ^{b *} values, the target ^L * ^a * ^{b *} and colorimetric ^L * ^a * ^{b *} value corresponding to the value of the color difference is calculated for each of the plurality of RGB values (S200 ), The calculated color differences ΔE are stored in the memory 40.

When each color difference ΔE is stored in the memory 40, the control unit 20 outputs a determination result screen in which each RGB value is associated with the color difference ΔE to the display unit 21. FIG. 6 is a diagram showing the determination result screen SC2. As shown in the figure, a color difference ΔE between the target L ^* a ^* b ^* value corresponding to each RGB value and the colorimetric L ^* a ^* b ^* value is displayed on the screen SC2. In the present embodiment, the point where the color difference ΔE is less than 1.0 indicates that the color deviation between the target L ^* a ^* b ^* value and the colorimetric L ^* a ^* b ^* value is small. "Is displayed. On the other hand, for the point where the color difference is 1.0 or more, a character string “NG” indicating that the color deviation between the target L ^* a ^* b ^* value and the colorimetric L ^* a ^* b ^* value is large is displayed. Is done. The threshold value is not limited to 1.0, and may be 2.0, for example. As a result, the user can easily recognize a color difference shift corresponding to each RGB value.

  The screen SC2 includes a color patch output button B5 and a cancel button B6. The user can select whether or not he / she wishes to output a color patch again in order to correct the color conversion table 42a by referring to the screen SC2. When desiring to output a color patch, the user presses the color patch output button B5. On the other hand, when the user does not wish to output the color patch, the user presses the cancel button B6.

  Subsequently, the control unit 20 determines which button is designated by the user (S300). When the output of the color patch is not desired (that is, when the user presses the button B6) (S300 NO), the control unit 20 ends the correction process of the color conversion table of FIG.

  On the other hand, when output of a color patch is desired (that is, when the user presses the button B5) (S300 YES), the control unit 20 executes a color patch determination process (S400).

  FIG. 7 is a flowchart showing the color patch determination process (S400 in FIG. 3).

  The control unit 20 determines an RGB value for determining a color patch to be output first among a plurality of predetermined RGB values (that is, RGB values satisfying the above-described formula (1)) (S410). ). In this embodiment, the RGB value ((R, G, B) = (255, 255, 255)) having the highest brightness is first determined as the RGB value for determining the value of the color patch.

Subsequently, the control unit 20 refers to the memory 40 to determine the color difference ΔE calculated in S200 (that is, the color difference between the target L ^* a ^* b ^* value and the colorimetric L ^* a ^* b ^* value). Read (S420).

  Subsequently, the control unit 20 determines whether or not the color difference read in S420 is less than a threshold value (1.0 in this embodiment) (S430). When the color difference is less than the threshold value (S430 YES), the control unit 20 proceeds to S470 without determining a color patch to be newly output. For example, as indicated by X1 in FIG. 6, the color difference ΔE in the RGB values (255, 255, 255) is 0.2. Therefore, the process proceeds to S470.

  On the other hand, when the color difference is equal to or larger than the threshold value in S430 (NO in S430), the control unit 20 performs a change amount determination process that is executed to calculate the change amount s that is a parameter necessary for outputting the color patch. Execute (S440). For example, as indicated by X2 in FIG. 6, the color difference ΔE in the RGB values (80, 80, 80) is 3.5. Therefore, a change amount determination process is executed.

  FIG. 8 is a flowchart showing the change amount determination process (S440 in FIG. 7). The change amount s determined in the change amount determination process is a parameter determined according to the lightness of the RGB value selected in S410. In other words, the change amount s is a parameter indicating a CMYK value that should be changed according to the color difference between the two colors when the color having one lightness is changed to a color having another lightness. .

The control unit 20 selects a notable RGB value (that is, the colorimetric L ^* a ^* b ^* value read in S420) for determining the change amount s among the RGB values included in the color conversion table 42a. Two RGB values having a small brightness difference are selected (S441). For example, in the case of calculating the change amount s corresponding to the RGB value of (R, G, B) = (224, 224, 224), the control unit 20 (R, G, B) = (240, 240, 240) and (R, G, B) = (208, 208, 208) RGB values are selected. The two points may be determined by different methods. For example, two RGB values having a small color difference may be selected from the noteworthy RGB values.

FIG. 9 is a diagram illustrating parameters used in the change amount determination process. Here, of the two RGB values selected in S441, the lightness component of the colorimetric L ^* a ^* b ^* value for the RGB value having a high lightness is La, and the RGB value having a high lightness is converted by the color conversion table 42. In this case, the CMYK value is (C, M, Y, K) = (Ca, Ma, Ya, Ka). When the color component Lb of the colorimetric L ^* a ^* b ^* value for the RGB value with low lightness among the two RGB values specified in S441 is converted to Lb and the RGB value with low lightness is converted by the color conversion table 42 The CMYK values of (C, M, Y, K) = (Cb, Mb, Yb, Kb).

The control unit 20 calculates the brightness difference between the colorimetric L ^* a ^* b ^* values of the two RGB values selected in S441 (S442). Specifically, the brightness difference is calculated based on the following formula (7). Note that abs () indicates the absolute value of the value in parentheses.

  ΔL = abs (La−Lb) (3)

  Subsequently, the control unit calculates a difference between CMY values corresponding to each of the two RGB values selected in S441 (S443). Specifically, the CMY value difference ΔMat is calculated based on the following equation (8).

  ΔMat = {abs (Ca−Cb) + abs (Ma−Mb) + abs (Ya−Yb)} / 3 Formula (4)

  Subsequently, the control unit 20 corrects the CMY value difference ΔMat based on the difference between the K components corresponding to the two RGB values selected in S441 (S444). Specifically, a value ΔMat ′ obtained by correcting the CMY value difference ΔMat is calculated based on the following equation (9).

  ΔMat ′ = ΔMat + d × abs (Ka−Kb) (5)

  (d: weighting count (0 <d ≦ 1))

  Thus, in this embodiment, the CMY value difference ΔMat is corrected by the difference between the K components corresponding to the two RGB values selected in S441. By doing so, since the K component is reflected in the change amount s, it is possible to more appropriately output the color patch of the gray axis direction affected by the K component.

  Finally, the control unit 20 calculates the change amount s based on the following equation (10) (S445).

  s = ΔMat ′ / ΔL (6)

  When the change amount determining process is completed, the control unit 20 determines, based on the change amount s determined in the change amount determining process, one color patch to be newly output and a color adjacent to the one color patch. The patch interval between the patches is determined (S450). Specifically, the patch interval Δx is determined based on the following equation (2). Note that the patch interval Δx is a CMYK value for expressing one of the color patches output in S500 of FIG. 3 and a CMYK for expressing a color patch adjacent to the one color patch. The difference between the values is shown.

  Δx = ΔE × s / n (7)

(ΔE: color difference between target L ^* a ^* b ^* value and colorimetric L * a * b value *, s: change amount, n: number of divisions)

  Note that the value of the division number n is stored in the memory 40 in advance. As the division number n is larger, the patch interval Δx is smaller, and the number of color patches output per unit distance is larger. Note that the value of the division number n is set to 4, for example.

  When the color patch interval Δx is determined, the control unit 20 determines the value of the newly output color patch (S460). Specifically, a color patch to be output is determined based on the following equation.

  For example, regarding the C component, assuming that the C component of the color patch color before correction is C1, and the C component of the color patch color to be newly output is C2, C2 is expressed as follows.

  C2 = C1 + Δx × {(− n / 2) + k} (k = 0, 1,..., N) Expression (8)

  That is, n + 1 color patches are output for the C component.

  Similarly, the M component and the Y component are also expressed as follows.

  M2 = M1 + Δx × {(− n / 2) + k} (k = 0, 1,..., N) (9)

  Y2 = Y1 + Δx × {(− n / 2) + k} (k = 0, 1,..., N) Expression (10)

  FIG. 10 is a diagram illustrating a method for determining a color patch to be newly output. As shown in the figure, based on the color patch interval Δx, each of the C component, the M component, and the Y component is independently changed one by one to output a color patch, whereby (n + 1) × (n + 1) X (n + 1) color patches are output.

  Subsequently, the control unit 20 determines whether or not the processing for all the RGB values satisfying the expression (1) is completed (S470). If there is an RGB value for which an output color patch has not been determined (NO in S470), the control unit 20 returns the process to S420. In this way, the process is executed for all RGB values included in the color conversion table 42a.

  When the color patch determination process is executed, the control unit 20 instructs the printer 70 to output a plurality of color patches determined by the color patch determination process (S500). Thereafter, the control unit 20 instructs the colorimeter 80 to measure the color of each output color patch (S600).

The control unit 20 receives a plurality of colorimetric L ^* a ^* b ^* values for each color patch from the colorimeter 80, and corrects the color conversion table 42a based on the plurality of colorimetric L ^* a ^* b ^* values. (S800).

Specifically, the control unit 20 determines the colorimetric L ^* a ^* b ^* value having the smallest color difference from the target L ^* a ^* b ^* value among the plurality of received colorimetric L ^* a ^* b ^* values. Select. Thereafter, the control unit 20, the target ^L * ^a * ^{b *} closest colorimetric ^L * ^a * ^{b *} value to a value (i.e., the target ^L * ^a * ^{b *} color difference is smallest between the value ^L * ^a * ^{b *} 2nd colorimetric table 42d in which the CMYK value obtained by color measurement is determined and the colorimetric L ^* a ^* b ^* value closest to the target L ^* a ^* b ^* value is associated with the CMYK value. Is generated. The control unit 20 changes the CMYK value corresponding to the color measurement L ^* a ^* b ^* value of the color conversion table 42a with the CMYK value of the second color measurement table 42d.

  The control unit 20 modifies the color conversion table 42a based on the second color measurement table 42d shown in FIG. FIG. 11 is a diagram showing correction of the color conversion table 42a. FIG. 11A shows the old color conversion table 42a before the color conversion table correction process is executed, and FIG. 11B shows the new color conversion table 42e after the color conversion table process is executed. As shown in the figure, the control unit 20 converts CMYK values corresponding to RGB values (R (n), G (n), B (n)) to (C1 (n), M1 (n), Y1 (n). , K1 (n)) to (C2 (n), M2 (n), Y2 (n), K2 (n)), specifically, included in the old color conversion table 42a (C1 (n) , M1 (n), Y1 (n), K1 (n)), some of the CMYK values are corrected to (C2 (n), M2 (n), Y2 (n), K2 (n)) Is generated.

In the above description, among the color conversion programs executed by the control unit 20, S100 in FIG. 6 corresponds to the processing executed by the first acquisition unit 51 of the present invention.
Also, S450 and S460 in FIG. 7 and S442, S443, and S445 in FIG. Further, S500 and S600 in FIG. 3 correspond to processing executed by the second acquisition unit 53. 3 corresponds to the process executed by the correction unit 54. The memory 40 corresponds to the first storage unit 55 and the second storage unit 58. Further, S420 and S430 of FIG. Further, S444 in FIG. 8 corresponds to the processing executed by the correction means 57.

As described above, the terminal device 10 according to the present exemplary embodiment acquires L ^* a ^* b ^* values corresponding to predetermined RGB values from the colorimeter 80 in order to correct the color conversion table 42a. Based on the CMYK value corresponding to the RGB value and the amount of change s depending on the lightness component L of the colorimetric L ^* a ^* b ^* value, the terminal device 10 has a plurality of colors to be newly measured. Determine the patch. Thereafter, the terminal device 10 corrects the color conversion table 42a using the determined colorimetric values of the plurality of color patches.

  Thus, the terminal device 10 according to the present embodiment can appropriately determine a plurality of color patches to be measured. Specifically, the amount of change s has a feature that the amount of change s decreases as the lightness L of the RGB values in the color conversion table 42a increases. As a result, the patch interval Δx between the plurality of color patches output for the RGB value is increased. As a result, the larger the lightness L of the RGB value, the larger the interval between the color patches for the RGB value. Thus, an appropriate number of color patches can be output according to the lightness ΔL and the change amount s.

  Note that the RGB space in this embodiment corresponds to the first color space in the present invention, and the CMYK space corresponds to the second color space.

B. Variation:
The technical scope of the present invention is not limited to the above-described embodiments, and can be implemented in various modes as described below.

  (1) In the above-described embodiment, the change amount s is determined by the change amount determination process shown in S440, but another configuration may be used. In other words, the change amount correspondence table as shown in FIG. 12 may be stored in the memory 40 in advance, and the change amount s may be determined by referring to the change amount correspondence table. Each change amount in the change amount correspondence table is preferably determined so that the change amount s decreases as the brightness increases (that is, as the RGB value increases).

  (2) In the above-described embodiment, it is described that the terminal device 10 determines a color patch to be output, but a different configuration may be used. That is, the color patch to be output by the control unit of the printer 70 connected to the terminal device 10 may be determined.

  In the above-described embodiment, it has been described that the printer 70 and the colorimeter 80 have different configurations. Instead, a configuration in which the colorimeter 80 is included in the printer 70 is adopted. Also good.

(4) In the foregoing embodiment, in S700 of FIG. 3, in the received colorimetric ^L * ^a * ^{b *} values, the target ^L * ^a * ^{b *} closest to the value colorimetric ^L * ^a * ^{b *} value Although the color conversion table 42a is modified using the CMYK values corresponding to, different configurations may be used. For example, even if five colorimetric L ^* a ^* b ^* values close to the target L ^* a ^* b ^* value are extracted and the color conversion table 42a is corrected with the average value of the CMYK values corresponding to each of the five points. Good.

  (5) In each of the above-described embodiments, the functions of the units 51 to 58 are realized by the CPU 30 executing the process according to the color conversion program 41. At least one of the units 51 to 58 is a logic circuit. Or the like.

  DESCRIPTION OF SYMBOLS 10 ... Terminal device, 20 ... Control part, 21 ... Display part, 22 ... Operation part, 23 ... Interface, 30 ... CPU, 40 ... Memory, 41 ... Color conversion program, 42 ... Table, 42a ... Color conversion table, 42b ... Target table, 42c ... first color measurement table, 42d ... second color measurement table, 51 ... first acquisition means, 52 ... decision means, 53 ... second acquisition means, 54 ... correction means, 55 ... first Storage means 56 ... Calculation means 57 ... Correction means 58 ... Second storage means 70 ... Printer 80 ... Colorimeter

Claims (8)

A control device for correcting a color conversion table for converting a color value expressed in a first color space into a color value expressed in a second color space,
First acquisition means for acquiring a first colorimetric value corresponding to a color expressed using a specific value of the second color space included in the color conversion table;
A determining unit configured to determine a plurality of values expressed in the second color space based on the specific value and an amount of change depending on lightness of the first colorimetric value;
Second acquisition means for acquiring a plurality of second colorimetric values obtained from a plurality of colors expressed using the plurality of values;
Correction means for correcting the specific value included in the color conversion table using the plurality of second colorimetric values;
A control device comprising: The control device according to claim 1,
First storage means for storing a target colorimetric value to be obtained from a color expressed using the specific value;
A calculation means for calculating a color difference between the target colorimetric value and the first colorimetric value;
The said correction means corrects the said specific value of the said color conversion table, when the said color difference is more than a specific color difference. The control apparatus characterized by the above-mentioned. The control device according to claim 1 or 2,
The correcting means corrects the specific value of the color conversion table using a value for expressing a color corresponding to one colorimetric value selected from the plurality of second colorimetric values. A control device characterized by: The control device according to any one of claims 1 to 3,
The change amount is determined based on at least three color components constituting the specific value. The control device according to any one of claims 1 to 4,
The control device, further comprising: a correction unit that corrects the amount of change based on a black component constituting the specific value. A control device according to any one of claims 1 to 5,
A second storage that stores a correspondence table composed of a plurality of sets in which values expressed in the second color space and amounts of change with respect to values expressed in the second color space are associated with each other. Means further comprising
The correspondence table includes: a first change amount with respect to a first value expressed in the second color space; and a second change amount with respect to a second value having a lightness greater than the first value. Including at least
The second change amount is smaller than the first change amount,
The control means determines a plurality of values expressed in the second color space by referring to the correspondence table. The control device according to any one of claims 1 to 6,
At least three of the color components constituting each of the plurality of values are the same value. A computer for correcting a color conversion table for converting a color value expressed in a first color space into a color value expressed in a second color space;
First acquisition means for acquiring a first colorimetric value corresponding to a color expressed using a specific value of the second color space included in the color conversion table;
A determining unit configured to determine a plurality of values expressed in the second color space based on the specific value and an amount of change depending on lightness of the first colorimetric value;
Second acquisition means for acquiring a plurality of second colorimetric values obtained from a plurality of colors expressed using the plurality of values;
Correction means for correcting the specific value included in the color conversion table using the plurality of second colorimetric values;
A program that executes

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