JP2017220894A - Data conversion device, data conversion method and data conversion program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data conversion device which implements data conversion reflected with gray balance when performing color conversion of color information represented in a first color space into color information in a second color space.SOLUTION: A data conversion device comprises: a reference color setting part which inputs a first array associating color information in a first color space with color information in a second color space, sets multiple pieces of color information including achromatic colors in the color information of the first array as reference colors and inputs color information in any other input color than the reference colors; a basic color space generation part for generating a basic color space represented by fixing the reference colors that are set by the reference color setting part, to grid points; an interpolation processing part for interpolating the color information in the input color by using the color information in the reference colors disposed at the grid points of the basic color space that is generated by the basic color space generation part; and an array generation part for generating a second array associating the color information in the first color space and the color information in the second color space while including the color information in the input color that is interpolated by the interpolation processing part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a data conversion apparatus, a data conversion method, and a data conversion program for converting image data. In particular, the present invention relates to a data conversion apparatus, a data conversion method, and a data conversion program for converting color image data expressed in different color spaces.

  An image device such as a display or a printer uses image data in which the color of each pixel constituting an image is expressed by gradation with a specific color component. In order to define the color used for the image data, for example, a color space such as an RGB color space or a CMYK color space is used (R: Red, G: Green, B: Blue, C: Cyan, M: Magenta, Y: Yellow, K: Black).

  In general, since the color used for the image data depends on the device, in order to output the same image with the same color between different devices, it is necessary to perform color conversion in order to match the colors between the devices. For example, the color of a photograph taken by an imaging device such as a digital camera is expressed in an RGB color space, and the data is described in RGB values. On the other hand, a printing device that prints a photograph uses colors expressed in the CMYK color space. Therefore, when the same color is expressed between the imaging device and the printing device, it is necessary to perform color conversion between the RGB color space and the CMYK color space. Thus, when colors are matched between devices using different color spaces, a look-up table (LUT: Lookup Table) that defines color correspondence is used.

  It is impractical to define the correspondence relationship of all colors that can be output by each image device using the LUT because of the relationship between the storage capacity of the apparatus and the amount of work when creating the LUT. For this reason, it is general that the correspondence relationship between a specific number of representative colors is defined by an LUT, and the correspondence relationship between colors other than the representative colors is calculated by interpolation. In other words, in general color conversion, color measurement is not performed for all colors that can be expressed, and color measurement is performed by outputting a color within the colorimetric range from an image device, and for a specific number of representative colors. Define the LUT.

  In order to create an LUT, not only does it take an enormous amount of time, but it also requires advanced expertise in color separation. For this reason, when creating an LUT, it is necessary for an expert to take into account color reproducibility and make adjustments to improve color reproducibility, such as individually specifying ink color characteristics and dot gain values. In light of such a background, it is required to facilitate the creation of an LUT and to realize color conversion with good color reproducibility without a high level of expertise.

  Patent Document 1 discloses a profile creation method that facilitates creation of an LUT. In the method of Patent Document 1, color values are obtained when a plurality of ink amounts are output at the ink amount. Then, color values associated with a plurality of grid points in a predetermined color space are acquired, and an initial LUT in which the plurality of grid points are associated with the ink amount via the acquired color values is created.

JP 2007-43488 A

  According to the method of Patent Document 1, by creating an initial LUT in which a plurality of grid points in a predetermined color space are associated with ink amounts, it is possible to easily create an LUT without a high level of expertise. . However, since the method of Patent Document 1 does not consider gray balance that is important as a color evaluation index in actual operation, gray balance is lost in the process of color separation, and gray red or blue fog occurs. There was a problem.

  In order to solve the above-described problem, the present invention provides a data conversion device that realizes color conversion reflecting gray balance when color information expressed in a first color space is converted into a second color space. The purpose is to provide.

  The data conversion device of one embodiment of the present invention receives a first array that associates color information of a first color space and a second color space, and includes a plurality of achromatic colors included in the color information of the first array. The reference color setting unit that inputs color information of the input color other than the reference color and the basic color that is expressed by fixing the reference color set by the reference color setting unit to the grid points A basic color space generation unit that generates a space, and an interpolation processing unit that interpolates color information of an input color using color information of a reference color arranged at a grid point of the basic color space generated by the basic color space generation unit And an array generation unit that generates a second array that associates the color information of the first color space and the second color space, including the color information of the input color interpolated by the interpolation processing unit.

  In the data conversion method of one aspect of the present invention, a first array that associates color information of the first color space and the second color space is input, and a plurality of achromatic colors are included among the color information of the first array. The basic color space is generated by setting the color information of the reference color as the reference color, and the reference color is fixed to the grid point, and the color information of the input color other than the reference color is input and placed at the grid point of the basic color space. The second color color information of the first color space and the second color space are associated with each other by interpolating the color information of the input color using the color information of the reference color and including the color information of the interpolated input color. Generate an array of

  A data conversion program according to one embodiment of the present invention includes a process of inputting a first array that associates color information of a first color space and a second color space, and an achromatic color among the color information of the first array. Processing to set multiple color information as a reference color, processing to generate a basic color space that expresses a reference color fixed to a grid point, processing to input color information of an input color other than the reference color, and basic color The first color space and the second color, including the process of interpolating the color information of the input color using the color information of the reference color arranged at the grid points of the space, and the color information of the interpolated input color And causing the computer to execute a process of generating the second array in which the color information of the space is associated.

  According to the present invention, it is possible to provide a data conversion device that realizes color conversion reflecting gray balance when color information expressed in the first color space is converted into the second color space.

1 is a block diagram illustrating a configuration of a color conversion apparatus according to a first embodiment of the present invention. It is an example of the color information input into the color conversion apparatus which concerns on the 1st Embodiment of this invention. It is a conceptual diagram of the basic color space which the color conversion apparatus concerning the 1st Embodiment of this invention produces | generates. It is an example of LUT (Lookup Table) which the color converter which concerns on the 1st Embodiment of this invention outputs. It is a conceptual diagram which shows an example of a general color space. It is a conceptual diagram which shows taking out a solid | solid from the basic color space produced | generated by the color conversion apparatus which concerns on the 1st Embodiment of this invention. FIG. 3 is a conceptual diagram of a solid taken out from a basic color space generated by the color conversion device according to the first embodiment of the present invention. FIG. 3 is a conceptual diagram of a solid taken out from a basic color space generated by the color conversion device according to the first embodiment of the present invention. FIG. 3 is a conceptual diagram of a solid taken out from a basic color space generated by the color conversion device according to the first embodiment of the present invention. 5 is a flowchart for explaining the operation of the color conversion apparatus according to the first embodiment of the present invention. It is a block diagram which shows the structure of the color converter which concerns on the 2nd Embodiment of this invention. It is an example of the input color information input into the color converter which concerns on the 2nd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the color conversion apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the color conversion apparatus which concerns on the 3rd Embodiment of this invention. It is a conceptual diagram which shows an example of the user interface of the color conversion apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the color conversion apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the color converter which concerns on the 4th Embodiment of this invention. It is a block diagram which shows an example of the hardware constitutions for performing the color conversion device concerning each embodiment of the present invention.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. However, the preferred embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following. In addition, in all the drawings used for description of the following embodiments, the same reference numerals are given to the same parts unless there is a particular reason. In the following embodiments, repeated description of similar configurations and operations may be omitted.

(First embodiment)
〔Constitution〕
First, the configuration of the data conversion apparatus according to the first embodiment of the present invention will be described with reference to the drawings. The data conversion apparatus according to the present embodiment performs gray balance when mapping color information expressed in an input color space (also referred to as a first color space) to an output color space (also referred to as a second color space). An LUT (Lookup Table) for realizing the reflected color conversion is generated. The LUT generated in this embodiment is an array that associates color information between different devices.

  In the following, an example of color conversion of an input color having color information in which an RGB color space and a CMYK color space are associated will be described (R: Red, G: Green, B: Blue, C: Cyan, M: Magenta). Y: Yellow, K: Black). The RGB color space is a color space that expresses colors by additive mixing using the color information of the three colors of red R, green G, and blue B. The CMYK color space is a color space that expresses colors by subtractive mixing using color information of four colors of cyan C, magenta M, yellow Y, and black K. Note that the method of the present embodiment is not limited to color conversion of input colors having color information in which the RGB color space and the CMYK color space are associated with each other, but to color conversion of input colors having color information belonging to an arbitrary color space. Applicable.

  FIG. 1 is a block diagram illustrating a configuration of a color conversion apparatus 10 that is a data conversion apparatus according to the present embodiment. The color conversion apparatus 10 includes a reference color setting unit 11, a basic color space generation unit 12, an interpolation processing unit 13, a processing result storage unit 14, and an LUT generation unit 15.

  The reference color setting unit 11 acquires color information belonging to an arbitrary color space as input data. The reference color setting unit 11 arranges the color information of a predetermined color included in the input data at the lattice points of the basic color space generated by the basic color space generation unit 12. That is, the reference color setting unit 11 arranges the acquired color information of the predetermined color at the lattice points of the basic color space and outputs the information to the basic color space generation unit 12.

  Here, the color information input to the reference color setting unit 11 will be described. FIG. 2 is an example of color information input to the reference color setting unit 11. Note that the color information in FIG. 2 is an example, and does not limit the scope of the present invention.

  In the example of FIG. 2, the color information input to the reference color setting unit 11 exists on the outermost contour (1 to 24) of the color gamut and on the lightness axis (25 to 29) indicating the gradation of the achromatic color. This is an information group for recording a plurality of color information in association with each other. Of the color information input to the reference color setting unit 11, a data set that is a set of color information set to the reference color is referred to as a basic data set 100 (also referred to as a first array). That is, color information included in the basic data set 100 and color information not included in the basic data set 100 (also referred to as other color information) are input to the reference color setting unit 11. The basic data set 100 and other color information may be input simultaneously, or may be input separately. Note that the numbers shown at the left end of the basic data set 100 in FIG. 2 are numerical values assigned to distinguish the colors, and need not be included in the basic data set 100.

  FIG. 3 is a conceptual diagram of the basic color space 120 generated by the color conversion apparatus 10 of the present embodiment. The basic data set 100 summarizes data stored in grid points that constitute a basic color space 120 including attributes of hue H (Hue), saturation S (Saturation), and lightness V (Value) that are the basis of color conversion. It is a thing. Details of the basic color space 120 in FIG. 3 will be described later.

  The basic color space generation unit 12 generates the basic color space 120 in FIG. 3 using the basic data set 100 input from the reference color setting unit 11. The basic color space generation unit 12 generates a color space having attributes of hue H, saturation S, and brightness V, and the color information of the basic data set input from the reference color setting unit 11 is used as hue H, saturation S, It is converted into an attribute of brightness V. Then, the basic color space generation unit 12 maps each conversion value to the generated color space, and generates a basic color space 120 having each element as a grid point. Since the lattice points of the basic color space 120 are fixed points, the color information converted into the attributes of hue H, saturation S, and brightness V has fixed values.

  The interpolation processing unit 13 inputs color information (referred to as input color X) from the reference color setting unit 11 via the basic color space generation unit 12. The interpolation processing unit 13 reads color information (CMYK values) of lattice points around other colors (hereinafter referred to as input color X) stored in the basic color space 120. Then, the interpolation processing unit 13 calculates color information (CMYK value) corresponding to the input color X from the read color information (CMYK value) of the grid points. The interpolation processing unit 13 outputs the calculated interpolation processing result to the processing result storage unit 14. In the example of FIGS. 7 to 9, the case where the input color X is a single color is described. However, the color information may be converted sequentially or in parallel for a plurality of input colors. In color conversion of an image, it is common to perform color conversion for a plurality of colors.

  The processing result storage unit 14 stores color information after interpolation processing obtained from the interpolation processing unit 13. The interpolation processing result calculated by the interpolation processing unit 13 may be output to the LUT generation unit 15 as it is.

  The LUT generation unit 15 reads the color information subjected to the color conversion process from the processing result storage unit 14. The LUT generation unit 15 performs color conversion processing into a LUT description format for mapping colors expressed in the color space of the input device to the color space of the output device. For example, the LUT generation unit 15 performs color conversion on color information expressed by RGB values into color information expressed by CMYK values. That is, when the LUT generation unit 15 reads the color information after the color conversion process from the processing result storage unit 14, the LUT generation unit 15 generates LUT data based on the read information, and an LUT reflecting the gray balance (also referred to as a second array). ) Is output.

  FIG. 4 is an example of an LUT (LUT 150) output by the LUT generation unit 15. The LUT 150 of FIG. 4 is obtained by adding color information of an arbitrary input color X to the color information of the basic data set 100 of FIG. The LUT 150 in FIG. 4 is an array for realizing color conversion reflecting gray balance between the input device and the output device.

  In the above example, the color conversion apparatus 10 creates a basic color space 120 by inputting a basic data set, and performs color conversion using the basic color space 120 for any input color X not included in the basic data set. The LUT reflecting the gray balance is output. The color conversion apparatus 10 can also input an existing LUT (first LUT), convert it to another LUT (second LUT) using the basic color space 120, and output it. In this case, the first LUT corresponds to the first array, and the second LUT corresponds to the second array.

[Color conversion processing]
Here, a color conversion process performed by the color conversion apparatus 10 will be described with reference to the drawings. 3 and 5 to 9 are conceptual diagrams for explaining the color conversion processing according to the present embodiment.

  A solid composed of a cylinder and a cone illustrated in FIG. 3 is an example of the basic color space 120 generated by the basic color space generation unit 12. A solid (basic color space 120) in FIG. 3 represents a color space including attributes of hue H, saturation S, and brightness V.

  In the basic color space 120, the hue H is represented by the center angle of a circle in a cross section (circle) when cut perpendicularly to the rotation axis (brightness axis) of the cone and cylinder forming the basic color space 120. Hue H is represented by a numerical value in the range of 0 to 360. In FIG. 3, the hue H is set to the reference (0) for red, 60 for yellow, 120 for green, 180 for cyan, 240 for blue, and 300 for magenta.

  In the basic color space 120, the saturation S is the distance from the center of the circle (lightness axis) on the cut surface (circle) perpendicular to the rotation axis (lightness axis) of the cone and cylinder constituting the basic color space 120. expressed. The saturation S is represented by a numerical value in the range of 0 to 100. In FIG. 3, the saturation S is set to 0 (center of the circle) for an achromatic color, and set to 100 (on the outer circumference of the circle) for a pure color.

  In the basic color space 120, the lightness V is represented by a numerical value set on the lightness axis. The brightness V is represented by a numerical value in the range of 0 to 255 with the vertex of the cone as the origin. The lightness V is the darkest when 0 and the brightest when 255. Further, the basic color space 120 in FIG. 3 is represented by a cone when the brightness V is in the range of 0 to 64, and by a cylinder when the brightness V is in the range of 64 to 255.

  An example of a procedure for creating the basic color space 120 by the basic color space generation unit 12 is as follows. First, the basic color space generation unit 12 maps the color information of the achromatic color on the lightness axis indicating the gradation of the achromatic color. Then, the basic color space generation unit 12 has a lattice point on which the color information having the highest lightness is arranged as a vertex and a lattice point located on the circumference of the bottom surface of the cone with the lightness axis passing through the vertex as a rotation axis. The color information of the reference color of the chromatic color having the same brightness as the reference color of the achromatic color mapped on the lightness axis is mapped. Further, the basic color space generation unit 12 shares the cone and the bottom surface with the lightness axis as the rotation axis, and the achromatic color mapped on the lightness axis to the grid points on the outermost contour of the cylinder with the lightness axis as the rotation axis. The color information of the chromatic reference color having the same brightness as the reference color is mapped. Note that the procedure for creating the basic color space 120 may not be in the above order. Further, the numerical ranges of the hue H, the saturation S, and the brightness V are not limited to the above numerical ranges, and can be arbitrarily set according to the setting conditions of the color information to be used.

  The circles on the lightness axis of the basic color space 120 and the outer circumference of the cylinder shown in FIG. 3 are obtained by mapping the color information (basic data set) input to the color conversion device 10 to the grid points of the basic color space 120. Each color information mapped in the basic color space 120 in FIG. 3 is treated as a fixed value fixed to each grid point.

  In FIG. 3, color information of red at grid point 1, yellow at grid point 2, green at grid point 3, cyan at grid point 4, blue at grid point 5, and magenta color information at grid point 6 is arranged. Then, color information of colors having a lightness V smaller than that of the grid points 1 to 6 by one step (255 → 192) is arranged at the grid points 7 to 12. Similarly, color information of a color whose brightness V is smaller by one level (192 → 128) than the lattice points 7 to 12 is arranged at the lattice points 13 to 18, and the lattice points 19 to 24 are more than the lattice points 13 to 18. Color information of a color with a small lightness V is arranged in one step (128 → 64).

  In FIG. 3, grid points 25 to 29 are arranged on the lightness axis. That is, white color information is arranged at the lattice point 25, light gray at the lattice point 26, gray at the lattice point 27, dark gray at the lattice point 28, and black information at the lattice point 29. That is, on the lightness axis, achromatic color information with the smallest lightness V is arranged at the lattice point 25, and achromatic color information with the largest lightness V is arranged at the lattice point 29. Then, achromatic (gray) color information is arranged at the lattice points 26 to 28 so that the brightness V gradually increases from the lattice point 25 toward the lattice point 29.

  FIG. 5 is an example of a general RGB color space (hereinafter referred to as RGB color space 121). The color information of the color set in the circles shown in the cube constituting the RGB color space 121 of FIG. 5 is arranged at the grid points of the basic color space 120 of FIG. The RGB values in the RGB color space 121 are expressed in 256 gradations from 0 to 255, with the origin at the bottom left vertex of the cube. Color information of red R, green G, blue B, cyan C, magenta M, yellow Y, white W, and black K is arranged at the vertex of the RGB color space 121.

  When the color information in the RGB color space 121 in FIG. 5 and the lattice points in the basic color space 120 in FIG. 3 are associated with each other, R (255, 0, 0) is lattice point 1, and G (0, 255, 0) is lattice. Points 3 and B (0, 0, 255) are arranged at the grid point 5. Further, C (255, 0, 255) is arranged at the lattice point 4, M (255, 0, 255) is arranged at the lattice point 6, and Y (255, 255, 0) is arranged at the lattice point 2. W (255, 255, 255) is arranged at the lattice point 25, and K (0, 0, 0) is arranged at the lattice point 29. A straight line connecting K (0, 0, 0) and W (255, 255, 255) corresponds to the brightness axis in the RGB color space of FIG.

  FIG. 6 is an example in which a plurality of grid points in the basic color space 120 are grouped and the basic color space 120 is divided by a solid formed by the grouped grid points. In the example of FIG. 6, the basic color space 120 is divided by a solid in which four or six adjacent lattice points are grouped. That is, the basic color space 120 is divided into solids 131 having four lattice points as vertices in the range of lightness V from 0 to 64, and six lattice points as vertices in the range of lightness V from 64 to 255. Divided into a solid 132.

  The interpolation processing unit 13 converts color information (input color X) input to the color conversion device 10 into values of hue H, saturation S, and brightness V (also referred to as HSV values). Then, the interpolation processing unit 13 searches in which solid the HSV value after conversion of the input color X is stored. The interpolation processing unit 13 calculates color information (CMYK value) corresponding to the input color X from the color information (CMYK value) of the lattice points (4 or 6) constituting the searched solid by interpolation processing.

  When the lightness V of the input color X is in the range of 0 to 64, the interpolation processing unit 13 searches for a solid 131 having four lattice points as vertices. When the lightness V of the input color X is in the range of 64 to 255, the interpolation processing unit 13 searches for a solid 132 having six lattice points as vertices. When the lightness V of the input color X is 64, the input color X is located on both the upper bottom surface of the solid 131 and the lower bottom surface of the solid 132. Therefore, when the lightness V of the input color X is 64, the interpolation processing unit 13 may search for either the solid 131 or the solid 132.

FIG. 7 shows the relationship between the color information (CMYK values) arranged at the lattice points of the solid 131 and the input color X stored in the solid 131. Similarly, FIG. 8 shows the relationship between color information (CMYK values) arranged at grid points of the solid 132 and the input color X stored in the solid 132. Note that the grid points G _i of FIG. 7 and FIG. 8, CMYK values _{(C i, M i, Y} i, K i) color information of is located (i: integer).

  For example, when the input color X is a skin color, the color information of the input color X is an RGB value (200, 150, 100). At this time, when the input RGB value is converted into an HSV value, the HSV value becomes (30, 127, 200).

  At this time, since the lightness V is 200, the input color X is stored in the solid 132 having six lattice points as vertices (hue H: 0 to 60, saturation S: 0 to 100, lightness). V: 192-255). The vertices of the solid 132 storing the input color X are lattice point 1 (red) having a lightness V of 255, lattice point 2 (yellow) and lattice point 7 (white), lattice point 7 (red) having a lightness V of 192, Grid point 8 (yellow) and grid point 26 (light gray).

  The color information of each grid point corresponds to the CMYK value of the color information (data set) input to the color conversion device 10. In correspondence with the basic data set of FIG. 2, when the brightness V is 255, red is (3, 97, 94, 0), yellow is (0, 2, 97, 0), and white is (0, 0, 0). , 0) color information. 2, when V is 192, red is (10, 98, 98, 0), yellow is (17, 15, 96, 0), and light gray is (18, 12). , 12, 7). The interpolation processing unit 13 obtains a CMYK value of the input color X by performing an interpolation process using the color information of these grid points. Note that general interpolation processing can be used for the interpolation processing performed by the interpolation processing unit 13.

  So far, the method of obtaining the CMYK value of the input color X from four or six points of the color information set as the reference color has been described, but the method of obtaining the CMYK value of the input color X is not limited to this. For example, as shown in FIG. 9, a new grid point is added in the saturation S direction, and the CMKY value of the input color X is obtained using the color information (CMYK value) arranged at the added new grid point. Also good. The color information (CMYK value) of the added grid point as shown in FIG. 9 is estimated from the color information of 6 points arranged as the reference color.

For example, as shown in FIG. 9, CMYK values of the grid points G ₇ to add between the grid points G ₁ and the lattice point G ₃ are, CMYK grid points G ₁ and grid point G ₃ adjacent to the grid point G ₇ Estimate using the value. Similarly, the CMYK value of the lattice point G ₈ is estimated using the CMYK values of the lattice point G ₂ and the lattice point G ₃ . Further, the CMYK value of the lattice point G ₉ is estimated using the CMYK values of the lattice point G and the lattice point G ₆ . In addition, the CMYK value of the lattice point G ₁₀ is estimated using the CMYK values of the lattice point G ₅ and the lattice point G ₆ .

  The reference color setting unit 11 sets the added new color information as a new reference color. For example, the basic color space generation unit 12 adds to the basic color space 120 grid points for arranging color information of a new reference color set by the reference color setting unit 11.

In the example of FIG. 9, the input color X is stored in the solid 133 having _eight vertices (grid points G ₁ , G ₂ , G ₄ , G ₅ , G ₇ , G ₈ , G ₉ and G ₁₀ ). ing. In the case of the example in FIG. 9, the interpolation processing unit 13 can calculate color information (CMYK value) corresponding to the input color X from the color information (CMYK value) of the eight points constituting the searched solid 133 by interpolation processing. . Note that the addition of new grid points is not limited to the example of FIG.

  The above is the description of the configuration of the color conversion apparatus 10 of the present embodiment.

[Operation]
Next, the operation of the LUT creation process by the color conversion apparatus 10 of the present embodiment will be described. FIG. 10 is a flowchart illustrating an example of the operation of the LUT creation process by the color conversion apparatus 10. In the description of FIG. 10, the components of the color conversion device 10 are described as the subject of the operation.

  In FIG. 10, first, the reference color setting unit 11 reads color information including gray balance, and acquires the read color information (step S101). For example, the reference color setting unit 11 acquires color information in response to an instruction signal output in response to a user operation or triggered by input of color information.

  The reference color setting unit 11 converts the acquired color information so that it can be mapped to a color space having attributes of hue H, saturation S, and brightness V (step S102).

  Here, different processing is executed depending on whether or not the basic color space 120 has been created (step S103).

  When the basic color space 120 has not been created (No in step S103), the reference color setting unit 11 determines whether or not the converted color information includes the basic data set 100 (step S104).

  When it is determined that the input color information includes the basic data set (Yes in step S104), the reference color setting unit 11 sets the color information included in the basic data set as the reference color (step S105). On the other hand, when it is determined that the input color information does not include the basic data set (No in step S104), the reference color setting unit 11 returns to step S101 and further acquires color information. At this time, a signal requesting a basic data set may be output.

  Then, the basic color space generation unit 12 generates the basic color space 120 of FIG. 3 using the reference color set by the reference color setting unit 11 (step S106). Thereafter, the process returns to step S101, and further color information is acquired. Note that the processing may be terminated in step S106 for the purpose of generating the basic color space 120.

  If the basic color space 120 has been created in step S103 (Yes in step S103), the interpolation processing unit 13 searches which solid in the basic color space 120 the input color information is included in (step S103). Step S107). At this time, the interpolation processing unit 13 acquires color information (CMYK values) of a plurality of grid points adjacent to the search result.

  The interpolation processing unit 13 calculates the CMYK value of the input color information using the acquired color information of the grid points (step S108). At this time, the color information stored by the interpolation processing unit 13 can be stored in the processing result storage unit 14.

  The LUT generation unit 15 generates an LUT using the color information (CMYK) color-converted in Step 108 (Step S109). At this time, the color conversion apparatus 10 may end the process by outputting the created LUT, or may return to step S101 and continue acquiring the color information.

  The above is the description of the operation of the color conversion apparatus 10 of the present embodiment.

  As described above, in this embodiment, since color conversion is performed using the basic color space in which the achromatic color (gray) is fixed as the reference color, the red or blue fog is changed depending on the gradation when the gray gradation is displayed. Will not occur. That is, according to the present embodiment, color conversion with good color reproducibility reflecting the gray balance can be realized. Therefore, even if an achromatic color gradation image is color-converted by the method of the present embodiment, a color cast such as red or blue does not occur in the converted achromatic color gradation image.

  In a general color conversion device, when the color information of the achromatic part is subjected to color conversion processing, the hue changes due to the influence of other colors, and red or blue color cast may occur in the achromatic region. is there. On the other hand, according to the present embodiment, as described above, since color conversion is performed using the achromatic color (gray) fixed in the basic color space, the occurrence of color cast in the achromatic color region can be suppressed. That is, according to the present embodiment, an achromatic color is set as a reference color at a fixed grid point, and color information of the input color is converted using the grid point as a reference point, so that it is not affected by other colors. Achromatic color information can be converted.

(Second Embodiment)
Next, a color conversion device according to a second embodiment of the present invention will be described with reference to the drawings. In the following description, the characteristic part according to the present embodiment will be mainly described. Therefore, the same configurations as those in the first embodiment are denoted by the same reference numerals, and redundant description may be omitted.

  In the first embodiment, when the basic color space 120 is generated, the color information of all the grid points shown in FIG. 3 is used. On the other hand, in the present embodiment, not all of the color information shown in FIG. 2 is used when the basic color space 120 is generated. Specifically, in this embodiment, in order to ease the user's reference color formulation and input data creation work amount, the lightness V is the maximum in the outermost part of the input device among the color information that becomes the reference color. Color information and lightness axis color information are used.

〔Constitution〕
FIG. 11 is a block diagram illustrating a configuration of the color conversion apparatus 20 according to the present embodiment. As shown in FIG. 11, the color conversion apparatus 20 includes a reference color setting unit 21, a basic color space generation unit 12, an interpolation processing unit 13, a processing result storage unit 14, and an LUT generation unit 15, A reference color estimation unit 22 is provided. Note that the reference color setting unit 11, the basic color space generation unit 12, the interpolation processing unit 13, the processing result storage unit 14, and the LUT generation unit 15 have the same configuration as the color conversion device 10 of the first embodiment. Detailed description is omitted.

  The representative color setting unit 21 inputs arbitrary color information, and determines whether or not the input color information includes representative color information (hereinafter referred to as representative color information). When the input color information includes representative color information, the representative color setting unit 21 sets the color of the color information as a representative color. The representative color setting unit 21 obtains color information having the highest brightness among the color information on the outermost contour of the color gamut of the input color space (first color space) and color information indicating the gradation of the achromatic color. It can also be expressed by setting representative color information including at least a reference color (representative color).

  The representative color setting unit 21 sets the acquired data set of representative color information as a grid point in the basic color space 120 and sends the data to the reference color estimation unit 22.

  Here, the representative color information input to the representative color setting unit 21 will be described. The representative color information is representative color information among all the color information corresponding to the grid points of the basic color space to be created. The representative color information can also be expressed as composed of color information corresponding to the outermost grid points of the basic color space to be created.

  FIG. 12 is an example of representative color information (representative color data set 210) input to the color conversion apparatus 20. As illustrated in FIG. 12, the representative color setting unit 21 acquires a representative color data set 210 including representative information (representative colors) among color information to be set as the reference color. In the example of the representative color data set 210 in FIG. 12, cyan C, magenta M, yellow Y, red R, green G and blue B, and gray of four gradations are set as representative colors.

  The reference color estimation unit 22 estimates the color information of the grid points set by the representative color setting unit 21 as an intermediate color of the color information of the grid points located around the grid points. Note that the reference color estimation unit 22 can also be expressed as estimating color information of another reference color using the representative color information set by the representative color setting unit 21.

  The reference color estimation unit 22 sends the estimated intermediate color to the reference color setting unit 11. In this embodiment, an example in which the reference color is determined in advance will be described. However, the number of reference colors may be set by an external system.

  The color information including the intermediate color estimated by the reference color estimation unit 22 is obtained from the reference color setting unit 11, the basic color space generation unit 12, the interpolation processing unit 13, the processing result storage unit 14, and the LUT generation unit 15 according to the first embodiment. It is processed in the same way.

  The above is the description of the configuration of the color conversion apparatus 20 according to the present embodiment.

[Operation]
Next, the operation of the color conversion apparatus 20 will be described with reference to the drawings. FIG. 13 is a flowchart illustrating an example of the operation of the color conversion apparatus 20. In the description of FIG. 13, the constituent elements of the color conversion device 20 are described as the subject of the operation.

  In FIG. 13, first, the reference color setting unit 11 reads color information including gray balance, and acquires the read color information (step S201). For example, the reference color setting unit 11 acquires color information in response to an instruction signal output in response to a user operation or triggered by input of color information.

  The reference color setting unit 11 converts the acquired color information so that it can be mapped to a color space having attributes of hue H, saturation S, and brightness V (step S202).

  Here, different processing is executed depending on whether or not the basic color space 120 has been created (step S203).

  If the basic color space 120 has not been created (No in step S203), the reference color setting unit 11 determines whether or not the converted color information includes the representative color data set 210 (step S204).

  When the reference color setting unit 11 determines that the input color information includes the representative color data set 210 (Yes in step S204), the reference color setting unit 11 sets the color information included in the representative color data set 210 to the representative color (step S204). S205).

  The reference color estimation unit 22 uses the set representative color to estimate a reference color that is not included in the representative color (step S205).

  Then, the reference color setting unit 11 sets the estimated color information as a reference color (step S206).

  The basic color space generation unit 12 generates the basic color space 120 based on the set reference color (step 207). Here, it returns to step S201. The process may be configured to end in step S208 for the purpose of generating the basic color space 120.

  On the other hand, when the reference color setting unit 11 determines that the input color information does not include the representative color data set 210 (No in step S204), the reference color setting unit 11 returns to step S201 and further acquires color information. At this time, a signal requesting a basic data set may be output.

  When the basic color space 120 has been created in step S203 (Yes in step S203), the interpolation processing unit 13 searches which solid in the basic color space 120 includes the input color information ( Step S209). At this time, the interpolation processing unit 13 acquires color information (CMYK values) of a plurality of grid points adjacent to the search result.

  The interpolation processing unit 13 calculates the CMYK value of the input color information using the acquired color information of the grid points (step S210). At this time, the color information stored by the interpolation processing unit 13 can be stored in the processing result storage unit 14.

  The LUT generation unit 15 generates an LUT using the color information (CMYK) color-converted in step 210 (step S211). At this time, the color conversion apparatus 10 may end the process by outputting the created LUT, or may return to step S201 and continue acquiring color information.

  The above is the description of the operation of the color conversion device 20 of the present embodiment.

  As described above, according to the present embodiment, color conversion with good color reproducibility reflecting the gray balance can be realized as in the first embodiment. In particular, according to the present embodiment, by estimating the reference color from the representative color, the color information to be set by the user is significantly reduced compared to the first embodiment, so that the user's workload is reduced. Increase efficiency.

(Third embodiment)
Next, a color conversion device according to a third embodiment of the present invention will be described with reference to the drawings. In the following description, the characteristic part according to the present embodiment will be mainly described. Therefore, the same reference numerals are assigned to the same configurations as those in the first or second embodiment, and redundant descriptions may be omitted.

  In the first and second embodiments, when performing color conversion, color conversion processing is performed using a preset reference color. On the other hand, in the present embodiment, the number of reference colors for color conversion (hereinafter simply referred to as the number of colors) can be set. In the present embodiment, an evaluation image color-converted using the basic color space is displayed, and color conversion is executed using the number of colors set with reference to the evaluation image. In the present embodiment, for example, an evaluation image displayed on a user interface (hereinafter referred to as UI; User Interface) is recognized by the user, and color conversion is performed based on the number of colors set by the user referring to the evaluation image. Run.

〔Constitution〕
FIG. 14 is a block diagram illustrating a configuration of the color conversion apparatus 30 according to the present embodiment. As shown in FIG. 14, in addition to the reference color setting unit 11, the basic color space generation unit 12, the interpolation processing unit 13, the processing result storage unit 14, and the LUT generation unit 15, the color conversion device 30 includes a parameter setting unit 31, a color A conversion processing unit 32 and an image display unit 33 are provided. Note that the reference color setting unit 11, the basic color space generation unit 12, the interpolation processing unit 13, the processing result storage unit 14, and the LUT generation unit 15 have the same configuration as the color conversion device 10 of the first embodiment. Detailed description is omitted.

  The parameter setting unit 31 reads parameters relating to color information including a desired number of colors set based on an evaluation image displayed on a display (not shown) or the like. For example, the parameter setting unit 31 acquires input information such as a desired number of colors input by the user from an input device (not shown), and sets parameters based on the acquired input information. In the present embodiment, an example is given in which the parameter setting unit 31 treats a desired number of colors as input information, but other input information may be handled. The parameter setting unit 31 reads an evaluation image and extracts color information from the read evaluation image.

  The reference color setting unit 11 acquires the input evaluation image and the desired number of colors set by the parameter setting unit 31 as input data, and sets the acquired color information of the desired number of colors as a reference color. The reference color set by the reference color setting unit 11 is processed in the same manner as in the first embodiment by the basic color space generation unit 12, the interpolation processing unit 13, the processing result storage unit 14, and the LUT generation unit 15. Then, the LUT generation unit 15 outputs the generated LUT to the color conversion processing unit 32.

  The color conversion processing unit 32 performs color conversion processing by applying the LUT obtained from the LUT generation unit 15 to the evaluation image stored in advance. The color conversion processing by the color conversion processing unit 32 is to convert an image expressed in the color space of a certain input device into an image expressed in the color space of the output device. The color conversion processing unit 32 outputs the image for evaluation subjected to the color conversion processing to the image display unit 33. The evaluation image to be subjected to the color conversion process may be configured to be input from the outside.

  The image display unit 33 displays the image on the display device having a display function of the evaluation image converted by the color conversion processing unit 32. For example, the image display unit 33 adjusts parameters for inputting a display area for displaying an evaluation image expressed in at least one of the input color space and the output color space, and parameters relating to color information including a desired number of colors. The UI including the area is displayed on an arbitrary display device. The user can set a desired number of colors used for the color conversion process while referring to an evaluation image displayed on a display unit such as a UI.

  Here, an example of a UI for displaying an evaluation image will be described. FIG. 15 is an example of a UI having a display unit that displays display information of the color conversion device 30. In the example of FIG. 15, the UI is displayed on the display 301 connected to the computer 300 on which the color conversion device 30 is mounted. The user can set the desired number of colors by operating the icons on the UI with the mouse 302 while sliding the slide bar for changing parameters while referring to the evaluation image displayed on the display 301. . Note that the arrangement positions of buttons, bars, etc. on the UI of FIG. 15 are merely examples, and can be arbitrarily changed.

  In the upper left part of the display 301 in FIG. 15, a “read” button and a “save” button are arranged. The “read” button is an icon operated when reading the input image and the color information of the reference color. The “save” button is an icon operated when saving parameters and the like set by the user. For example, the color conversion device 30 reads the input image and the color information of the reference color according to a signal generated when the user operates a “read” button.

  In the lower part of the display 301 in FIG. 15, a slide bar for adjusting parameters for designating the number of colors of hue H, saturation S, and brightness V of the basic color space 120 is arranged. That is, the UI in FIG. 15 includes a parameter adjustment area that can be adjusted by the user to the desired number of colors based on the read number of colors.

  In the central part of the UI in FIG. 15, an evaluation image before color conversion and an evaluation image after color conversion that has been color-converted according to a parameter value set by a UI sludge bar are displayed. For example, when the color conversion apparatus 30 reads the color information of the reference color according to the signal generated when the user operates the “read” button, the color of the evaluation image is read using the number of colors of the read reference color. And the evaluation images before and after the conversion are arranged and displayed on the UI.

  For example, the user can adjust the parameters while comparing the evaluation image before color conversion displayed on the display 301 with the evaluation image color-converted using the basic color space. At this time, the parameter adjusted by the user is set in the color conversion device 30 as the new number of colors.

  The above is the description of the configuration of the color conversion device 30 of the present embodiment.

[Operation]
Next, the operation of the color conversion apparatus 30 of the present embodiment will be described using a flowchart. FIG. 16 is a flowchart for explaining the operation of the color conversion apparatus 30 of the present embodiment. In the description of FIG. 16, the components of the color conversion device 30 will be described as the main subject of operation.

  16, first, the parameter setting unit 31 reads a parameter file relating to the number of colors (number of grid points) of hue H, saturation S, and brightness V set by the user referring to the UI of FIG. 15 (step S301). ). The parameter file is a file containing parameters set by the user.

  The parameter setting unit 31 reads an image for color conversion evaluation in accordance with a user operation (step S302).

  The parameter setting unit 31 extracts color information from the evaluation image input in step S302 (step S303).

  Then, the interpolation processing unit 13 performs interpolation processing on the color information extracted in step 303 using the number of colors of hue H, saturation S, and brightness V set by the parameter file (step S304).

  The LUT generation unit 15 creates an LUT using the CMYK values calculated in step 304 (step S305).

  The color conversion processing unit 32 performs color conversion processing on the evaluation image using the LUT created in step 305 (step S306).

  The image display unit 330 causes the display 301 to display the evaluation image that has undergone the color conversion processing in step 306 in accordance with the above-described display mode such as FIG. 15 (step S307).

  The above is the description of the operation of the color conversion device 30 of the present embodiment.

  The color conversion apparatus according to this embodiment has a configuration in which parameters can be adjusted so that evaluation images before and after conversion have the same color while a user refers to evaluation images before and after color conversion. Note that the configuration of the present embodiment is not limited to the configuration of FIG. For example, the color conversion apparatus 30 may automatically adjust the parameters by using a calculation such as a color difference between the colors before and after color conversion.

As described above, according to the present embodiment, color conversion with good color reproducibility reflecting the gray balance can be realized in the first embodiment. In addition, according to the present embodiment, the evaluation image converted by the number of reference colors constituting the basic color space is presented to the user, and the user who refers to the evaluation image can set the desired number of colors. A basic color space with an appropriate number of colors can be provided.
In particular, according to the present embodiment, since the user can set appropriate parameters using the UI, convenience can be improved. Note that the UI configuration in the present embodiment may be applied to the second embodiment.

(Fourth embodiment)
Next, a color conversion device according to a fourth embodiment of the present invention will be described with reference to the drawings. The color conversion device of this embodiment is a high-level concept of the color conversion devices of the first to third embodiments.

〔Constitution〕
FIG. 18 is a block diagram showing the configuration of the color conversion device 40 of this embodiment. As shown in FIG. 10, the color conversion device 40 includes a reference color setting unit 41, a basic color space generation unit 42, an interpolation processing unit 43, and an LUT generation unit 44.

  The reference color setting unit 41 inputs a first array that associates color information of the first color space and the second color space. The reference color setting unit 41 sets achromatic color information among the color information included in the first array as a reference color. In addition, the reference color setting unit 41 inputs color information of input colors other than the reference color. The reference color setting unit 41 expresses that a plurality of pieces of color information including color information on the outermost contour of the color gamut of the first color space and color information indicating the gradation of the achromatic color are set as reference colors. You can also.

  The basic color space generation unit 42 generates a basic color space in which the reference color set by the reference color setting unit 41 is expressed by being fixed to grid points. The basic color space generation unit 42 expresses that the basic color space 120 is generated by mapping the reference color set by the reference color setting unit 41 to grid points with fixed hue, saturation, and brightness attributes. You can also

  The interpolation processing unit 43 interpolates the color information of the input color using the color information of the reference color arranged at the grid points of the basic color space 120 generated by the basic color space generation unit 42. The interpolation processing unit 43 arranges the color information of the input color in the basic color space 120 and the reference color arranged at the grid point close to the color information of the input color arranged at the grid point of the basic color space 120. It can also be expressed by interpolating the color information of the input color using the color information.

  The LUT generation unit 44 (also referred to as an array generation unit) includes a second color information that associates the color information of the first color space and the second color space, including the color information of the input color interpolated by the interpolation processing unit 43. Generate and output an array of.

  According to this embodiment, color conversion with good color reproducibility reflecting the gray balance can be realized.

(Hardware configuration)
Next, a hardware configuration for realizing the color conversion apparatus according to the first to fourth embodiments of the present invention will be described with an example.

  In each of the above-described embodiments, the components shown in FIGS. 1, 11, 14, and 17 can be realized by dedicated hardware such as a circuit. The components of each embodiment can also be realized as a function of a software program or a unit of processing (hereinafter referred to as a software module). However, the division of each component shown in the drawings of each embodiment is a configuration for convenience, and various configurations can be assumed in practical use.

  FIG. 18 is a block diagram of an information processing apparatus 500 that is an example of a hardware configuration that can realize the color conversion apparatus according to each embodiment of the present invention. The information processing apparatus 500 in FIG. 18 is configured as a server, a computer, or the like, and has a hardware environment that enables each function in the above-described embodiment. The information processing apparatus 500 can be configured by a general computer including a central processing unit, a main storage device, an auxiliary storage device, an interface (I / F), and the like. The central processing unit is also called a CPU (Central Processing Unit). The main storage device includes a ROM (Read Only Memory) and a RAM (Random Access Memory).

  As illustrated in FIG. 18, the information processing apparatus 500 includes a CPU 501, a ROM 502, a RAM 503, an auxiliary storage device 504, a communication interface 505, a drive device 506, and an input / output interface 507. The CPU 501, ROM 502, RAM 503, auxiliary storage device 504, communication interface 505, drive device 506, and input / output interface 507 are connected to each other by a bus 509 that is a common communication line. The information processing apparatus 500 is connected to a network 511, a recording medium 512, an external system, and an external apparatus via a communication interface 505.

  The CPU 501 is a central processing unit that expands a program stored in the auxiliary storage device 504 or the like in the RAM 503 and executes the expanded program. Each embodiment of the present invention can be realized by a configuration using a program installed in the information processing apparatus 500. Note that a module acquired via the network may be loaded into the RAM 503. The CPU 501 executes various arithmetic processes and control processes by executing the developed program.

  The ROM 502 is a main storage device that stores data such as instruction codes and constant data.

  The RAM 503 is a main storage device having an area where a program is expanded.

  The auxiliary storage device 504 is a storage device that stores various data such as a program group and various types of storage information. The auxiliary storage device 504 can be realized by a local disk such as a hard disk, a flash memory, or an SSD (Solid State Drive).

  The communication interface 505 is an interface connected to the network 511 and an external system / device.

  The drive device 506 is a device that reads and writes data stored in the recording medium 512. The drive device 506 reads a data program from the recording medium 512, writes a processing result of the information processing device 500 to the recording medium 512, and the like. The recording medium 512 can be realized by, for example, an optical recording medium such as a CD-ROM (Compact Disc-ROM) or a DVD-ROM (Digital Versatile Disc-ROM). The recording medium 512 may be realized by a semiconductor recording medium such as an SD (Secure Digital) card or a USB (Universal Serial Bus) memory, a magnetic recording medium such as a flexible disk, or other media.

  Input devices such as a keyboard, a mouse, and a touch panel may be connected to the information processing apparatus 500. These input devices are used for inputting information and settings. When a touch panel is used as an input device, the display screen of the display device may be a touch panel display that also serves as the user interface of the input device. The CPU 501 and the input device may be connected via the input / output interface 507.

  The information processing apparatus 500 may be connected to an output device such as a display device or a printer. For example, when a display device that displays an image is used, the display device may be connected to the input / output interface 95. For example, when a printer that prints information about an image or the like is used, the printer may be connected to the input / output interface 95.

  The processing of the color conversion device of each embodiment is realized by the following procedure. For example, a program capable of realizing the functions of the configuration diagrams (FIGS. 1, 11, 14, and 17) and the flowcharts (FIGS. 10, 13, and 16) shown in each embodiment is supplied to the information processing apparatus 500. The program supplied to the information processing apparatus 500 may be stored in the RAM 503 or the auxiliary storage device 504. The CPU 501 of the information processing apparatus 500 may expand the stored program in the RAM 503 and execute processing according to the expanded program.

  Further, a general procedure can be used as a method for supplying the program to the information processing apparatus 500. For example, the program may be installed in the information processing apparatus 500 via a recording medium 512 such as a CD-ROM, or the program may be downloaded from the outside via a communication line such as the Internet. In such a case, the function of the color conversion apparatus according to each embodiment is considered to be configured by a code constituting the program and a recording medium 512 in which the code is stored.

  The above is an example of a hardware configuration for enabling the color conversion apparatus according to the embodiment of the present invention. Note that the hardware configuration in FIG. 18 is an example of a hardware configuration that enables the color conversion apparatus of the present embodiment, and does not limit the scope of the present invention. Further, a color conversion program that causes a computer to execute processing by the color conversion apparatus of the present embodiment is also included in the scope of the present invention. Furthermore, a program recording medium that records the color conversion program according to the present embodiment is also included in the scope of the present invention. For example, the color conversion program of this embodiment can be recorded on the recording medium 512.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Color converter 11 Standard color setting part 12 Basic color space production | generation part 13 Interpolation processing part 14 Processing result memory | storage part 15 LUT production | generation part 20 Color conversion device 21 Representative color setting part 22 Reference color estimation part 30 Color conversion apparatus 31 Parameter setting part 32 color conversion processing unit 33 image display unit 40 color conversion device 41 reference color setting unit 42 basic color space generation unit 43 interpolation processing unit 44 LUT generation unit

Claims (10)

A first array for associating the color information of the first color space and the second color space is input, and among the color information of the first array, a plurality of color information including achromatic colors is set as a reference color. A reference color setting unit for inputting color information of an input color other than the reference color;
A basic color space generation unit that generates a basic color space for expressing the reference color set by the reference color setting unit fixed to a grid point;
An interpolation processing unit for interpolating color information of the input color using color information of the reference color arranged at a grid point of the basic color space generated by the basic color space generation unit;
An array generation unit that generates a second array that associates the color information of the first color space and the second color space, including color information of the input color interpolated by the interpolation processing unit; Data conversion device. The reference color setting unit includes:
A plurality of pieces of color information including color information on the outermost contour of the color gamut of the first color space and color information indicating a gradation of an achromatic color are set as the reference color;
The basic color space generation unit
The data conversion apparatus according to claim 1, wherein the basic color space is generated by mapping the reference color set by the reference color setting unit to grid points with fixed attributes of hue, saturation, and brightness. The basic color space generation unit
Map the color information of the achromatic color to the lightness axis indicating the gradation of the achromatic color,
The reference color of the color information with the lightness is the achromatic color of the lightness axis at the lattice point of the conical color space with the lightness axis as the rotation axis and the lattice point where the color information with the highest lightness is arranged. Mapping according to the color information,
The reference color of the color information with small lightness is made to correspond to the color information of the achromatic color of the lightness axis at the grid point of the columnar color space in contact with the bottom surface of the conical color space with the lightness axis as the rotation axis. The data conversion apparatus according to claim 2, wherein the basic color space is generated by mapping. The interpolation processing unit
The color information of the input color is arranged in the basic color space, and the color information of the input color is used by using the color information of the reference color arranged at a grid point close to the input color arranged in the basic color space. The data conversion apparatus according to any one of claims 1 to 3, wherein information is interpolated. The reference color setting unit includes:
When any color information other than the reference color is set as a new reference color, lattice points for arranging the color information of the new reference color are set in the basic color space,
The basic color space generation unit
5. The data conversion apparatus according to claim 4, wherein a new basic color space in which color information of the new reference color is arranged at the new grid point set by the reference color setting unit is generated. Representative color information including at least color information having the highest lightness among color information on the outermost contour of the color gamut of the first color space and color information indicating an achromatic gradation is set as the reference color. A representative color setting unit,
A reference color estimation unit that estimates color information of the reference color other than the representative color information by using the representative color information set by the representative color setting unit. A data conversion device according to claim 1. A parameter setting section for reading parameters relating to color information including the desired number of colors;
A color conversion processing unit that converts the color information of the first color space into color information of the second color space based on the second array generated by the array generation unit;
An image display unit for displaying an image expressed by the color information color-converted by the color conversion processing unit,
The reference color setting unit includes:
The data conversion apparatus according to any one of claims 1 to 6, wherein color information of the desired number of colors read by the parameter setting unit is set as the reference color. The image display unit
A display area for displaying at least one evaluation image expressed in at least one of the first color space and the second color space, and a parameter for color information including the desired number of colors. 8. The data conversion apparatus according to claim 7, wherein a user interface including a parameter adjustment area is displayed on an arbitrary display screen. Input a first array associating color information of the first color space and the second color space;
A plurality of pieces of color information including achromatic colors among the color information of the first array are set as reference colors;
Generating a basic color space for expressing the reference color by fixing it to a grid point;
Input color information of input colors other than the reference color,
Using the color information of the reference color arranged at the grid points of the basic color space, the color information of the input color is interpolated,
A data conversion method for generating a second array that associates color information of the first color space and the second color space, including the interpolated color information of the input color. A process of inputting a first array for associating color information of the first color space and the second color space;
A process of setting a plurality of pieces of color information including achromatic colors among the color information of the first array as reference colors;
A process of generating a basic color space for expressing the reference color fixed to a grid point;
A process of inputting color information of an input color other than the reference color;
A process of interpolating the color information of the input color using the color information of the reference color arranged at the grid points of the basic color space;
A data conversion program for causing a computer to execute a process of generating a second array in which color information of the first color space and the second color space is associated, including the interpolated color information of the input color.

Images