Image processing device, image processing method, and program

Abstract

To enable a change of a way of using a light system color material by a user.SOLUTION: An image processing device includes: a conversion part that converts a first collection of a gradation value in each processing color of each pixel of image data of a print object into a second collection of the gradation value in each of the processing color and a light system color material on the basis of a gradation value pf a certain processing color, a gradation value of the processing color in the case where a light system color material of which concentration is lower than that the processing color is used and information indicating a correspondence relation of a pair of the gradation values of the light system color material; a color region deterioration pixel identification part that identifies the pixel of which a color region of the pixel in regard to the second collection is reduced; an output part that outputs information that can recognizes the identified pixel; a setting change reception part that receives a change instruction of the correspondence relation from a user; and a print data generation part that generates image data that causes a print device to print on the basis of a result obtained by converting the first collection of each pixel of the image data is converted into the second collection by the conversion part on the basis of the correspondence relation in accordance with the change instruction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image processing device, an image processing method, and a program. [Background technology]

[0002] In printing, there is a technique for improving the graininess of midtones by using lighter colorants with a lower density than one or more of the commonly used process color (CMYK) colorants (inks, toners, etc.).

[0003] For example, Patent Document 1 discloses a technology that allows a user to select a "cost priority mode" before printing, thereby switching between printing using light-colored inks (inks corresponding to light color materials) and printing using only process colors (CMYK) at the user's discretion. Summary of the Invention [Problem to be solved by the invention]

[0004] Using a lot of light colorants improves granularity (apparent fineness), but this can also cause problems such as increased costs due to the increased total amount of colorant used, and a reduced color gamut for dark colors that are expressed using a lot of colorant due to the forced reduction in the amount of colorant used.

[0005] With conventional technology, the user can only decide whether or not to use light color materials, but cannot change how the light color materials are used (how much light color material to use for a certain gradation value) to suit the image data to be printed.

[0006] The present invention has been made in consideration of the above-mentioned points, and has an object to enable a user to change the way in which light color materials are used. [Means for solving the problem]

[0007] In order to solve the above problem, the image processing device has a conversion unit that converts a first set of gradation values ​​for each process color of each pixel of image data to be printed into a second set of gradation values ​​for each process color and for each light-colored colorant based on information indicating a correspondence between the gradation values ​​of a certain process color and a set of gradation values ​​of the process color and the gradation values ​​of the light-colored colorant when a light-colored colorant with a lower density than the process color is used, a color gamut reduction pixel identification unit that identifies pixels related to the second set where the color gamut is reduced, an output unit that outputs information that makes it possible to identify the identified pixels, a setting change acceptance unit that accepts an instruction to change the correspondence from a user, and a print data generation unit that generates image data to be printed by a printing device based on a result of the conversion unit converting the first set of each pixel of the image data into the second set based on the correspondence in response to the change instruction. Effect of the Invention

[0008] The manner in which light color materials are used can be changed by the user. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a configuration of an image processing system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating an example of a hardware configuration of an image processing device 10 according to an embodiment of the present invention. [Diagram 3] 1 is a diagram illustrating an example of a functional configuration of an image processing device 10 according to an embodiment of the present invention. [Figure 4] FIG. 13 is a diagram illustrating an example of decomposition setting. [Diagram 5] FIG. 13 is a diagram showing examples of other options for decomposition settings. [Figure 6] FIG. 13 is a diagram for explaining an ink limit. [Figure 7] 1 is a flowchart illustrating an example of a processing procedure executed by the image processing device 10. [Figure 8] 13A and 13B are diagrams illustrating output examples of a dark ink gamut and a light ink gamut. [Figure 9] FIG. 13 is a diagram illustrating an example of output of color gamut reduction pixel identification information. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In this embodiment, ink will be described as a specific example of a color material. A light color material is a color material that has a lower density than the color materials of process colors (CMYK). In this embodiment, the ink of the process color is called "dark ink." Ink equivalent to a light color material is called "light ink."

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of an image processing system in an embodiment of the present invention. In Fig. 1, a user terminal 20 is connected to an image processing device 10 via a network such as a LAN (Local Area Network) or the Internet. The image processing device 10 is connected to a printing device 30 via a network such as a LAN or the Internet.

[0012] The user terminal 20 is a device that functions as a user interface, and, for example, receives input of various instructions such as a print instruction from a user, and displays the processing results by the image processing device 10. The user terminal 20 transmits a print request indicating the contents of the print instruction to the image processing device 10. For example, a PC (Personal Computer), a smartphone, a tablet terminal, or the like may be used as the user terminal 20.

[0013] The image processing device 10 executes image processing on image data specified as a print target in a print request from the user terminal 20. For example, the image processing device 10 generates information indicating the effect on the print result of a reduction in color gamut caused by using light-colored inks, and generates print data for the image data when light-colored inks are used.

[0014] The printing device 30 is a device (printer) that executes printing using light color inks of one or more of the four colors of CMYK in addition to commonly used process color (CMYK) inks. In other words, light color inks are prepared for each of CMYK. However, which light color inks are used varies depending on the specifications of the printing device 30.

[0015] Fig. 2 is a diagram showing an example of a hardware configuration of an image processing device 10 according to an embodiment of the present invention. The image processing device 10 in Fig. 2 includes a drive device 100, an auxiliary storage device 102, a memory device 103, a processor 104, and an interface device 105, which are all connected to each other via a bus B.

[0016] A program for implementing processing in the image processing device 10 is provided by a recording medium 101 such as a CD-ROM. When the recording medium 101 storing the program is set in the drive device 100, the program is installed from the recording medium 101 to the auxiliary storage device 102 via the drive device 100. However, the program does not necessarily have to be installed from the recording medium 101, but may be downloaded from another computer via a network. The auxiliary storage device 102 stores the installed program as well as necessary files, data, and the like.

[0017] When an instruction to start a program is received, the memory device 103 reads out the program from the auxiliary storage device 102 and stores it. The processor 104 is a CPU or a GPU (Graphics Processing Unit), or a CPU and a GPU, and executes functions related to the image processing device 10 in accordance with the program stored in the memory device 103. The interface device 105 is used as an interface for connecting to a network.

[0018] Fig. 3 is a diagram showing an example of a functional configuration of the image processing device 10 according to the embodiment of the present invention. As shown in Fig. 3, the image processing device 10 includes a print request receiving unit 111, a light color use determining unit 112, a converting unit 113, a color gamut reduction pixel specifying unit 114, a first color gamut specifying unit 115, a second color gamut specifying unit 116, an output unit 117, an instruction accepting unit 118, a setting change accepting unit 119, a total amount restriction processing unit 120, a print data generating unit 121, and a transmitting unit 122. Each of these units is realized by a process in which one or more programs installed in the image processing device 10 are executed by the processor 104.

[0019] The print request receiving unit 111 receives a print request sent from the user terminal 20. The print request includes image data to be printed (hereinafter referred to as "input image data") and information indicating whether or not light-colored ink is to be used (hereinafter referred to as "light-color use information"). Whether or not light-colored ink is to be used is input by the user via a setting screen that the user terminal 20 displays when accepting a print instruction from the user, for example. The value of each pixel of the image data to be printed (hereinafter referred to as "pixel value") is expressed by a set or combination of gradation values ​​for each process color (CMYK) (hereinafter referred to as "CMYK value"), such as (C, M, Y, K) = (60, 40, 30, 90). The gradation value of a certain color is an index indicating the density of the color in 1 (%) increments from 0 to 100 (%). A gradation value of 100 (%) corresponds to the maximum density that the printing device 30 can express. The pixel value of the image data included in the print request may be an RGB value. In this case, the print request receiving unit 111 may convert each pixel value from an RGB value to a CMYK value using a known method (for example, a method using a correspondence table between RGB values ​​and CMYK values).

[0020] The light color use determination unit 112 determines whether or not light color ink is to be used based on light color use information included in the print request.

[0021] When it is determined that the use of light-colored inks is necessary, the conversion unit 113 converts (decomposes) the CMYK values ​​of each pixel of the input image data into a set of gradation values ​​for each process color (CMYK) and for each color of light-colored ink (hereinafter simply referred to as "light color"). In this embodiment, an example will be described in which light cyan (hereinafter referred to as "Lc"), which has a lower density than cyan (C), can be used as the light-colored ink. Therefore, the CMYK values ​​of each pixel are converted into a value (hereinafter also referred to as "CMYKLc value") that is composed of a set of the respective gradation values ​​of (C, M, Y, K, Lc). However, two or more light-colored inks corresponding to two or more colors of CMYK may be used.

[0022] Since Lc is a color with a lower density than C, the conversion process by the conversion unit 113 basically separates the C value of C in the CMYK value into the C and Lc values ​​in the CMYKLc value. Such conversion (separation) is performed based on preset information (hereinafter referred to as "separation setting").

[0023] Fig. 4 is a diagram showing an example of separation settings. In Fig. 4, the horizontal axis indicates the tone value of C (cyan) (before separation) as an input value for separation, and the vertical axis indicates the tone values ​​of C (cyan) and Lc (light cyan) (after separation) as output values ​​by separation.

[0024] The dashed line graph is a graph showing the correspondence between the gradation value of C of the input value and the gradation value of Lc (light ink of C) of the output value. The solid line graph is a graph showing the correspondence between the gradation value of C of the input value and the gradation value of C (dark ink of C) of the output value. For example, in the example of FIG. 4, an input value of C=50 is converted (decomposed) to C=30 and Lc=100. Also, an input value of C=70 is converted (decomposed) to C=60 and Lc=45. Therefore, the pixel value of a pixel with a CMYK value of (50,40,30,90) is converted to a CMYKLc value of (30,30,90,100). The pixel value of a pixel with a CMYK value of (70,40,30,90) is converted to a CMYKLc value of (60,30,90,45).

[0025] The graph in Fig. 4 is an example of a correspondence relationship between an input value and an output value that is selected as an initial value from a plurality of options that are set in advance. The user can arbitrarily set which correspondence relationship is to be the option and which option is to be the initial value.

[0026] For example, Fig. 5 is a diagram showing an example of other options for the decomposition setting. In Fig. 5, (1) is an option for the decomposition setting in which the maximum value of Lc has been changed (reduced) compared to Fig. 4. (2) is an option for the decomposition setting in which the slope of the dashed line for Lc (i.e., the degree of increase in Lc in response to an increase in the input value) has been changed compared to Fig. 4.

[0027] The conversion unit 113 initially converts (decomposes) the CMYK values ​​of each pixel of the input image data into CMYKLc values ​​based on the decomposition settings (FIG. 4) as initial values.

[0028] The color gamut-reducing pixel identifying unit 114 identifies pixels in which the color gamut is reduced (hereinafter referred to as "color gamut-reducing pixels") from among all pixels of the input image data. The color gamut-reducing pixel identifying unit 114 identifies pixels in which the sum of the gradation values ​​of the CMYK values ​​or CMYKLc values ​​(total amount of ink) exceeds a preset threshold value (hereinafter referred to as "ink limit") as color gamut-reducing pixels. The sum of the gradation values ​​of the CMYK values ​​or CMYKLc values ​​means the sum of the gradation values ​​of each of the CMYK values ​​in the case of CMYK values, and means the sum of the gradation values ​​of each of the CMYKLc values ​​in the case of CMYKLc values.

[0029] FIG. 6 is a diagram for explaining the ink limit. In printing, a limit (ink limit) is set for the amount of ink that can be used for one pixel. For pixels that exceed the ink limit, a process of reducing the gradation value so as not to exceed the ink limit (hereinafter referred to as "total amount limiting process") is performed. The total amount limiting process is performed regardless of whether or not light-colored ink is used, but as is clear from FIG. 4 and FIG. 5, when light-colored ink is used, for the color corresponding to the light-colored ink (C (cyan) in this embodiment), it is common that only light-colored ink is used up to a certain gradation value, and dark-colored ink and light-colored ink are mixed from a certain gradation value. Therefore, the total amount of ink used (the sum of the gradation values ​​of all colors) tends to be larger when light-colored ink is used than when only dark-colored ink is used (hereinafter also referred to as "dark-color printing") depending on the color density or hue. Therefore, even if a pixel does not exceed the ink limit during dark-color printing, the ink limit may be exceeded when light-colored ink is used (i.e., after conversion by the conversion unit 113).

[0030] The color gamut reduction pixel identifying unit 114 identifies such a pixel as a color gamut reduction pixel. For example, assume that the CMYK values ​​before the conversion by the conversion unit 113 are (C, M, Y, K) = (50, 60, 60, 60) = 230% in total, and the ink limit is 240%. When the conversion unit 113 converts the CMYK values ​​of the pixel into CMYKLc values ​​according to the separation settings shown in Figure G3, the CMYKLc values ​​become (C, M, Y, K, Lc) = (30, 60, 60, 60, 100) = 310% in total. In this case, since 310% exceeds the ink limit of 240%, the color gamut reduction pixel identifying unit 114 identifies the pixel as a color gamut reduction pixel. Note that the total amount restriction process for the color gamut reduction pixel is executed by the total amount restriction processing unit 120 described later. As a result of this total amount restriction process, the range of colors (color gamut) that can be reproduced is narrowed. A narrow color gamut is equivalent to being unable to express the colors of an input image exactly as they are.

[0031] The first color gamut specification unit 115 specifies a color gamut that can be reproduced only by dark inks (hereinafter referred to as "dark ink gamut") within the range of the ink limit. The specification of the dark ink gamut uses information (hereinafter referred to as "dark ink reproduction range information") in which all possible CMYK values ​​within the range of the ink limit are associated with colors reproduced by the CMYK values. In the dark ink reproduction range information, the colors associated with the CMYK values ​​are expressed, for example, by values ​​(hereinafter referred to as "Lab values") in the L*a*b* color system (or L*a*b* color space). The first color gamut specification unit 115 specifies a set of Lab values ​​corresponding to a certain hue (hereinafter referred to as "gamut comparison hue") from the dark ink reproduction range information as the dark ink gamut. The gamut comparison hue may be specified by the user or may be automatically determined by the first color gamut specification unit 115. The dark ink reproduction range information is stored in advance in, for example, the auxiliary storage device 102 or the like.

[0032] The second color gamut identification unit 116 identifies a color gamut (hereinafter referred to as a "light color use color gamut") that can be reproduced within the range of the ink limit when dark color inks and light color inks are used according to the separation setting used by the conversion unit 113 (for example, the separation setting in FIG. 4 at first). The light color use color gamut is identified using information (hereinafter referred to as "light color use reproduction range information") in which, among all possible CMYKLc values ​​in the separation setting used by the conversion unit 113, the CMYKLc values ​​that satisfy the ink limit (the sum of the gradation values ​​is equal to or less than the ink limit) are associated with the color reproduced by the CMYKLc value. In the light color use reproduction range information, the color associated with the CMYKLc value is expressed by, for example, Lab values. The second color gamut identification unit 116 identifies a set of Lab values ​​that correspond to the gamut comparison hue from the light color use reproduction range information as the light color use color gamut. Note that the light color use reproduction range information is stored in advance in the auxiliary storage device 102 or the like for each separation setting. That is, since the light color use reproduction range information differs depending on the separation setting, it is prepared in advance for each separation setting.

[0033] The output unit 117 outputs information capable of identifying gamut-reducing pixels (hereinafter referred to as "gamut-reducing pixel identification information") and information indicating the dark ink gamut and the gamut when light colors are used (hereinafter referred to as "light color use impact information") to the user terminal 20, thereby displaying the light color use impact information on the user terminal 20. As a result, the user can visually grasp the impact on printing, such as the range of gamut-reducing pixels in the input target image and how the gamut changes due to the use of light color inks. Based on the grasped information, the user decides whether or not to proceed with printing.

[0034] An instruction receiving unit 118 executes a process for receiving an instruction from the user as to whether or not to permit printing, based on the information output by the output unit 117.

[0035] If the user does not permit printing, the setting change receiving unit 119 executes a process for receiving a change to the separation setting from the user. For example, the setting change receiving unit 119 executes a process for receiving an instruction from the user to change to any of the separation settings exemplified in Fig. 5. The setting change receiving unit 119 may also receive from the user an instruction to use light color ink (to not use light color ink). When the setting change receiving unit 119 receives an instruction to change the separation setting, the processes from the conversion unit 113 onwards are executed again.

[0036] When a gamut-reduced pixel is identified by the gamut-reduced pixel identifying unit 114, the total amount restriction processing unit 120 executes total amount restriction processing for the gamut-reduced pixel. When the CMYKLc value of the gamut-reduced pixel is (C, M, Y, K, Lc) = (30, 60, 60, 60, 100) = 310% in total and the ink limit is 240%, the total amount restriction processing unit 120 reduces the ink amount (tone value) of the gamut-reduced pixel by 310% - 240% = 70%, so that the total tone value of the gamut-reduced pixel is 240% or less. In this case, the amount of CMYKLc to be reduced and the amount to be reduced are generally replaced with CMYKLc values ​​that express the color closest to the color before the total amount restriction processing, and various methods are known. In the present embodiment, the method of total amount restriction processing is not limited to a specific method.

[0037] The total amount restriction process is executed if there is a color gamut-reducing pixel even when light-colored inks are not used. In this case, the total amount restriction processor 120 changes the CMYK values ​​of the color gamut-reducing pixel so that the sum of the gradation values ​​of the CMYK values ​​is within the ink limit.

[0038] The print data generating unit 121 generates image data for printing (hereinafter referred to as "print data") from the input image data. When light-colored inks are used, the print data generating unit 121 generates image data as print data in which each pixel of the input image data has a CMYKLc value converted by the conversion unit 113 as the pixel value of each pixel. When light-colored inks are not used, the print data generating unit 121 generates print data based on the pixel value of each pixel of the input image data. However, when a total amount restriction process has been performed on any image by the total rainfall restriction unit regardless of whether light-colored inks are used or not, the print data generating unit 121 generates print data based on the CMYK value or CMYKLc value after the total amount restriction process has been performed.

[0039] The transmission unit 122 transmits the print data generated by the print data generation unit 121 to the printing device 30.

[0040] The following describes the processing procedure executed by the image processing device 10. Fig. 7 is a flowchart for explaining an example of the processing procedure executed by the image processing device 10.

[0041] In step S101, the print request receiving unit 111 receives a print request sent from the user terminal 20. The print request includes input image data, light color usage information, and the like.

[0042] Next, the light color use determination unit 112 determines whether or not light color ink is to be used based on the light color use information included in the print request (S102). If the light color use information indicates that light color ink is to be used, the light color use determination unit 112 determines that the use of light color ink is necessary, and if not, the light color use determination unit 112 determines that the use of light color ink is not necessary.

[0043] If the light color use determination unit 112 determines that the use of light color ink is necessary (Yes in S102), the conversion unit 113 converts (separates) the CMYK values ​​of each pixel of the input image data into CMYKLc values ​​based on the separation setting set as the initial value (S103). Hereinafter, the separation setting used by the conversion unit 113 is referred to as the "target separation setting."

[0044] Next, the color gamut reduction pixel identifying unit 114 identifies color gamut reduction pixels by determining whether or not the sum of the CMYKLc tone values ​​exceeds the ink limit for each pixel of the converted image data (S104).

[0045] If there is no gamut-reducing pixel (No in S104), proceed to step S114. If one or more pixels have been identified as gamut-reducing pixels (Yes in S104), the first gamut specification unit 115 specifies the dark ink gamut based on the dark ink reproduction range information. The dark ink gamut is a set of Lab values ​​that correspond to gamut comparison hues among the Lab values ​​associated with CMYK values ​​in the dark ink reproduction range information.

[0046] The color gamut comparison hue may be specified by the user, or may be automatically determined by the first color gamut specification unit 115. When the user specifies the color gamut comparison hue, for example, the user may input the color gamut comparison hue together with other print settings when issuing a print instruction using the user terminal 20. In this case, the user specifies one or more hues that are considered relatively important in the input image data (for example, that the user desires to reproduce with high accuracy when printing). When the first color gamut specification unit 115 automatically determines the color gamut comparison hue, for example, the first color gamut specification unit 115 may determine one or more color gamuts with high occurrence frequencies in the input image data as the color gamut comparison hue.

[0047] Next, the second color gamut identification unit 116 identifies the light color use color gamut based on the light color use reproduction range information corresponding to the target separation setting (S107). The light color use color gamut is a set of Lab values ​​corresponding to the color gamut comparison hue among the Lab values ​​associated with the CMYKLc values ​​in the light color use reproduction range information.

[0048] Next, the output unit 117 transmits (outputs) the light color usage impact information (color gamut reduction pixel identification information, and information indicating the dark ink gamut and the color gamut when light colors are used) to the user terminal 20, thereby causing the user terminal 20 to display the light color usage impact information (S108).

[0049] Fig. 8 is a diagram showing an example of output of the dark ink gamut and the light color gamut. In Fig. 8, (1) is the dark ink gamut and the light color gamut when the gamut comparison hue is blue. (2) is the dark ink gamut and the light color gamut when the gamut comparison hue is green. (3) is the dark ink gamut and the light color gamut when the gamut comparison hue is cyan.

[0050] In (1) to (3), the left side shows the dark ink gamut, and the right side shows the gamut when light colors are used. As described above, the dark ink gamut and the light ink gamut are both collections of Lab values, so if the hue is fixed, they can be plotted in a two-dimensional coordinate system with saturation and lightness as the coordinate axes. Note that in Figure 8, for convenience, the outline of the collection of Lab values ​​is expressed as the dark ink gamut or the light ink gamut, rather than the individual Lab values.

[0051] In (1), the color gamut when using light colors appears to have a shape in which part of the dark ink gamut is missing. According to the target separation setting, it can be seen that the color gamut for blue becomes narrower when light inks are used.

[0052] In (2), the color gamut when light colors are used has a smaller maximum saturation value than the dark ink gamut. According to the target separation setting, it can be seen that the color gamut for green becomes narrower when light inks are used.

[0053] In (3), the dark ink gamut and the gamut when light inks are used have almost the same shape. It can be seen that, according to the target separation setting, the use of light inks has almost no effect on the cyan gamut.

[0054] Note that Figure 8 shows that the color gamut is likely to change when light-color inks are used because mixed colors such as blue and green require a larger total ink amount. The color gamut when light colors are used varies depending on the separation settings, so depending on the separation settings, the difference between the color gamut when light colors are used and the dark-color ink gamut may be noticeable even for the hue of a single color (one of the CMYK colors) as in (3).

[0055] FIG. 9 is a diagram showing an example of output of gamut-reducing pixel identification information. For example, assume that the input image data is an image as shown in FIG. 9(1). This image includes a rectangle r1 and a circle c1. Of these, assume that all pixels constituting the circle c1 are gamut-reducing pixels. In this case, for example, as shown in FIG. 9(2), image data in which (all pixels of) the circle c1 are changed to a specific color (e.g., red, etc.) indicating that they are gamut-reducing pixels is output as gamut-reducing pixel identification information. In this way, the user can know the range of gamut-reducing pixels (i.e., the range that will not be printed in the same color as the input image data), and it is possible to prevent in advance the output of a printed matter that the user cannot accept.

[0056] The user determines whether or not an acceptable (or desired) print result can be obtained for the input image data based on the dark ink gamut and light ink gamut as shown in Fig. 8 and the gamut reduction pixel identification information as shown in Fig. 9, and inputs an instruction regarding whether or not to permit printing to the user terminal 20. The user terminal 20 transmits information indicating the instruction (hereinafter referred to as "instruction information") to the image processing device 10.

[0057] When the instruction receiving unit 118 of the image processing device 10 receives the instruction information (S109), it determines whether the instruction information indicates permission to print (S110). If the instruction information does not indicate permission to print (No in S110), the setting change receiving unit 119 executes a process for receiving a change to the disassembly setting from the user (S111).

[0058] For example, the setting change receiving unit 119 may cause the user terminal 20 to display a screen in which a graph showing a plurality of disassembly settings as illustrated in Fig. 4 or 5 is displayed as an option. In this case, when the user selects one of the options, the user terminal 20 transmits information indicating the option to the setting change receiving unit 119. The setting change receiving unit 119 specifies the disassembly setting related to the option indicated by the information as the destination disassembly setting.

[0059] Alternatively, the setting change receiving unit 119 may display a screen on the user terminal 20 for editing the target separation setting. Editing the separation setting is, for example, an operation of changing the separation setting by modifying the graph corresponding to the light color ink (changing the slope or maximum value, etc.) or modifying the graph corresponding to the dark color ink in FIG. 4. Since it is necessary to prepare in advance reproduction range information when using light colors according to the separation setting, the modifications possible by editing may be limited to a finite number of patterns. In this case, the user terminal 20 transmits information indicating the separation setting after editing to the setting change receiving unit 119. The setting change receiving unit 119 specifies the separation setting indicated by the information as the destination separation setting.

[0060] The setting change receiving unit 119 may further receive an instruction from the user to stop using the light color ink. In this case, the setting change receiving unit 119 causes the user terminal 20 to display a screen for receiving an instruction to stop using the light color ink, along with changing the separation settings. When the user terminal 20 receives an instruction to stop using the light color ink from the user, it transmits the instruction to stop using the light color ink to the setting change receiving unit 119.

[0061] Following step S111, steps S102 and after are executed again. At this time, if the setting change receiving unit 119 receives an instruction to stop using light color ink, the determination in step S102 is No. Alternatively, if the setting change receiving unit 119 identifies a new separation setting, in step S103, the new separation setting is used as the target separation setting.

[0062] By repeating step S102 and subsequent steps, the print result can be made closer to what the user desires.

[0063] When the instruction receiving unit 118 receives instruction information indicating permission to print (Yes in S110), the process proceeds to step S113.

[0064] If light-color printing is not used (No in S102), the color gamut reduction pixel identifying unit 114 identifies color gamut reduction pixels by determining whether the CMYK values ​​of each pixel in the input image data exceed the ink limit (S112). After step S112, the process proceeds to step S113.

[0065] In step S113, the total amount restriction processing unit 120 executes the total amount restriction process if a gamut-reducing pixel is identified. Therefore, if there is no gamut-reducing pixel, nothing is executed in step S113. The content of the total amount restriction process is as described above. The total amount restriction process may be executed before step S108 when the answer is Yes in step S105. In this case, in step S108, information indicating the color change before and after the total amount restriction process for the gamut-reducing pixel may be output. For example, according to the example of FIG. 9, a screen may be displayed on the user terminal 20 in which the image data generated by executing the total amount restriction process for all pixels of the circle c1 is arranged so as to be compared with the input image data of FIG. 9(1). This allows the user to understand the extent to which the color of the gamut-reducing pixel is changed from the input image data before printing.

[0066] Next, the print data generating unit 121 generates print data for the input image data (S114). The generation of the print data is as described above.

[0067] Next, the transmission unit 122 transmits the print data generated by the print data generation unit 121 to the printing device 30 (S115). The printing device 30 executes printing based on the print data.

[0068] As described above, according to this embodiment, the user can change the way light color materials are used (separation settings). At this time, the effects on the print result when light color materials (light inks) are used (dark ink gamut and light ink gamut, and gamut reduction pixel identification information) are presented to the user, so the user can obtain useful information on how to change the way light color materials are used (separation settings). As a result, the possibility of obtaining the print result desired by the user can be increased.

[0069] Each function of the above-described embodiment can be realized by one or more processing circuits. In this specification, the term "processing circuit" includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and a device such as an ASIC (Application Specific Integrated Circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), or a conventional circuit module designed to execute each function described above.

[0070] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to such specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims.

[0071] For example, aspects of the present invention are as follows. <1> a conversion unit that converts a first set of gradation values ​​for each process color of each pixel of the image data to be printed into a second set of gradation values ​​for each process color and for each light colorant based on information indicating a correspondence between the gradation value of a certain process color and a set of gradation values ​​of the process color and the light colorant when a light colorant having a lower density than the process color is used; a color gamut reducing pixel identifying unit that identifies pixels that reduce a color gamut among the pixels related to the second set; an output unit that outputs information that enables the specified pixel to be identified; a setting change receiving unit that receives an instruction to change the correspondence relationship from a user; a print data generation unit that generates image data to be printed by a printing device based on a result of the conversion unit converting the first set of pixels of the image data into the second set based on the correspondence relationship in response to the change instruction; 13. An image processing device comprising: <2> the color gamut reduction pixel identifying unit identifies pixels whose sum of gradation values ​​related to the second set exceeds a threshold value; Characterized by <1> The image processing device described herein. <3> the setting change receiving unit receives a change to a maximum value of the light colorant in the correspondence relationship, or a change to a degree of increase of the light colorant in response to an increase in a gradation value of the certain process color in the correspondence relationship. Characterized by <1> or <2> The image processing device described herein. <4> a first color gamut specification unit that specifies a set of first colors that can be reproduced by the first set based on information indicating a color corresponding to each of all the first sets whose sum of gradation values ​​does not exceed the threshold value; a second color gamut identification unit that identifies a second set of colors reproducible by the second set based on information indicating colors corresponding to each of the second sets whose sum of gradation values ​​does not exceed the threshold value among all the second sets when dark color inks and light color inks are used based on the correspondence relationship used by the conversion unit; and having the output unit outputs information indicating the first color set and the second color set. Characterized by <2> The image processing device described herein. <5> a conversion procedure for converting a first set of gradation values ​​for each process color of each pixel of the image data to be printed into a second set of gradation values ​​for each process color and for each light colorant, based on information indicating a correspondence between the gradation value of a certain process color and a set of gradation values ​​of the process color and the light colorant when a light colorant having a lower density than the process color is used; a gamut reducing pixel identification step of identifying pixels of said second set that have a gamut reduction; an output step of outputting information capable of identifying the identified pixel; a setting change receiving step of receiving an instruction to change the correspondence relationship from a user; a print data generation step of generating image data to be printed by a printing device based on a result of the conversion unit converting the first set of pixels of the image data into the second set based on the correspondence relationship in response to the change instruction; The image processing method according to claim 1, wherein the image processing method is executed by a computer. <6> a conversion procedure for converting a first set of gradation values ​​for each process color of each pixel of the image data to be printed into a second set of gradation values ​​for each process color and for each light colorant, based on information indicating a correspondence between the gradation value of a certain process color and a set of gradation values ​​of the process color and the light colorant when a light colorant having a lower density than the process color is used; a gamut reducing pixel identification step of identifying pixels of said second set that have a gamut reduction; an output step of outputting information capable of identifying the identified pixel; a setting change receiving step of receiving an instruction to change the correspondence relationship from a user; a print data generation step of generating image data to be printed by a printing device based on a result of the conversion unit converting the first set of pixels of the image data into the second set based on the correspondence relationship in response to the change instruction; A program characterized by being executed on a computer. [Explanation of symbols]

[0072] 10 Image processing device 20 User terminal 30 Printing device 100 Drive device 101 Recording media 102 Auxiliary storage device 103 Memory device 104 processors 105 Interface device 111 Print request receiver 112 Light color usage judgment section 113 Conversion unit 114 Gamut reduction pixel identification unit 115 1st color gamut identification section 116 Second color gamut identification section 117 Output section 118 Instructions Reception Department 119 Setting change reception section 120 Total amount control processing unit 121 Print data generation unit 122 Transmitter B Bus [Prior art documents] [Patent documents]

[0073] [Patent Document 1] Unexamined Japanese Patent Publication No. 2006-263938

Claims

1. a conversion unit that converts a first set of gradation values ​​for each process color of each pixel of the image data to be printed into a second set of gradation values ​​for each process color and for each light colorant based on information indicating a correspondence between the gradation value of a certain process color and a set of gradation values ​​of the process color and the light colorant when a light colorant having a lower density than the process color is used; a color gamut reducing pixel identifying unit that identifies pixels that reduce a color gamut among the pixels related to the second set; an output unit that outputs information that enables the specified pixel to be identified; a setting change receiving unit that receives an instruction to change the correspondence relationship from a user; a print data generating unit that generates image data to be printed by a printing device based on a result of the conversion unit converting the first set of pixels of the image data into the second set based on the correspondence relationship in response to the change instruction; 13. An image processing device comprising:

2. the color gamut reduction pixel identifying unit identifies pixels whose sum of gradation values ​​related to the second set exceeds a threshold value; 2. The image processing apparatus according to claim 1,

3. the setting change receiving unit receives a change to a maximum value of the light colorant in the correspondence relationship, or a change to a degree of increase of the light colorant in response to an increase in a gradation value of the certain process color in the correspondence relationship.

2. The image processing apparatus according to claim 1,

4. a first color gamut specification unit that specifies a set of first colors that can be reproduced by the first set based on information indicating a color corresponding to each of all the first sets whose sum of gradation values ​​does not exceed the threshold value; a second color gamut specification unit that specifies a set of second colors reproducible by the second set based on information indicating colors corresponding to each of the second sets whose sum of gradation values ​​does not exceed the threshold value among all the second sets when dark color inks and light color inks are used based on the correspondence relationship used by the conversion unit; and having the output unit outputs information indicating the first color set and the second color set.

3. The image processing apparatus according to claim 2.

5. a conversion procedure for converting a first set of gradation values ​​for each process color of each pixel of the image data to be printed into a second set of gradation values ​​for each process color and for each light-colored colorant, based on information indicating a correspondence between the gradation value of a certain process color and a set of gradation values ​​of the process color and the light-colored colorant when a light-colored colorant having a lower density than the process color is used; a gamut reducing pixel identification step of identifying pixels of said second set that have a gamut reduction; an output step of outputting information capable of identifying the identified pixel; a setting change receiving step of receiving an instruction to change the correspondence relationship from a user; a print data generating step of generating image data to be printed by a printing device based on a result of the conversion step of converting the first set of pixels of the image data into the second set based on the correspondence relationship in response to the change instruction; The image processing method according to claim 1, wherein the image processing method is executed by a computer.

6. a conversion procedure for converting a first set of gradation values ​​for each process color of each pixel of the image data to be printed into a second set of gradation values ​​for each process color and for each light-colored colorant, based on information indicating a correspondence between the gradation value of a certain process color and a set of gradation values ​​of the process color and the light-colored colorant when a light-colored colorant having a lower density than the process color is used; a gamut reducing pixel identification step of identifying pixels of said second set that have a gamut reduction; an output step of outputting information capable of identifying the identified pixel; a setting change receiving step of receiving an instruction to change the correspondence relationship from a user; a print data generating step of generating image data to be printed by a printing device based on a result of the conversion step of converting the first set of pixels of the image data into the second set based on the correspondence relationship in response to the change instruction; A program characterized by being executed on a computer.

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