Image processing device, image processing method, and program

Abstract

To suppress a gradation step in a region from the light color material to the dark color material in the case where the dark and light color materials are used in a mixed manner.SOLUTION: An image processing device generates a single color correction parameter for each of a normal color material and a light color material from a patch pattern formed using each of the normal color material and the light color material, and generates a mixed primary color correction parameter from a patch pattern formed using a mixed primary color obtained by mixing the normal color material and the light color material to which the single color correction parameter is applied. The image processing device specifies, as a modulation point, an input gradation value of the mixed primary color when an output of the normal color material is started in the mixed primary color based on a conversion table in which an input gradation value of the mixed primary color and an output gradation value of each of the normal color material and the light color material constituting the mixed primary color are associated with each other, and generates a correction chart in which the patch pattern corresponding to the modulation point is added to the patch pattern formed in stages.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, image forming devices have been known that are equipped with not only the four normal color materials of C (cyan), M (magenta), Y (yellow), and K (black), but also light color materials that have the same hue as the normal color materials but a lower density than the normal color materials.

[0003] In such image forming devices, normal color materials and light color materials are sometimes mixed for printing. When dark and light color materials are mixed, there is a problem that tone steps (false contours) occur due to the change in color material, especially in areas that exist in intermediate density regions and transition from light color materials to normal color materials.

[0004] Patent Document 1 discloses a technique for forming a pattern using dark toner and light toner, reading the density of the pattern formed on recording paper, and correcting the gradation characteristics of image data for light toner by changing the slope from a zero level based on the density characteristics of the read pattern and the usage ratio of dark and light toner. Patent Document 2 discloses a technique for obtaining the gradation characteristics of each color from a gradation patch pattern of each color including light color ink, generating a density correction table for each color, and then referencing a table showing each density value when dark and light color materials are mixed to generate an additional table for correcting the gradation characteristics when the color materials are mixed. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the gradation characteristics when mixing dark and light color materials vary depending on factors such as engine conditions, printing media, and dot shapes. Therefore, even if the density when mixing colors is corrected based only on information from a pre-existing table, it may not be possible to completely suppress gradation gaps.

[0006] The present invention has been made in consideration of the above, and aims to provide an image processing device, an image processing method, and a program that make it possible to suppress tone differences in the area where light color materials transition from light color materials to dark color materials when mixing light and dark color materials. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the present invention provides an image processing apparatus communicably connected to an image forming apparatus equipped with a normal colorant and a light-colorant having the same hue as the normal colorant and a lower density than the normal colorant, the image processing apparatus comprising: a single-color gradation correction parameter generating means for generating single-color correction parameters used to correct the gradation characteristics of each of the normal colorant and the light-colorant from data obtained by measuring patch patterns formed using the normal colorant and the light-colorant; and a single-color gradation correction parameter generating means for generating single-color correction parameters used to correct the gradation characteristics of each of the normal colorant and the light-colorant from data obtained by measuring patch patterns formed using a mixed primary color output by applying the single-color correction parameters to the normal colorant and the light-colorant. and a mixed primary color gradation correction parameter generation means for generating mixed primary color correction parameters used for correcting the characteristics, wherein the mixed primary color gradation correction parameter generation means comprises: a modulation point identification means for identifying, as a modulation point, a gradation value of the mixed primary color when output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color color material that constitute the mixed primary color; and a chart generation means for generating a correction chart in which patch patterns corresponding to the modulation points are added to the patch patterns of the mixed primary color that are formed in stages with a predetermined gradation value width. [Effects of the Invention]

[0008] According to the present invention, when light and dark color materials are mixed and used, it is possible to suppress tone differences in the area where the light color material transitions to the dark color material. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of an image processing system according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of a DFE according to the first embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of the functional configuration of a DFE according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the functional configuration of the tone correction parameter generating unit according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing an example of the layout of a single-color measurement chart according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating a method for generating a single color tone correction parameter according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the functional configuration of the light color mixture gradation correction chart output processing unit according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of a conversion table according to the first embodiment. [Figure 9] FIG. 9 is a diagram showing an example of the layout of the mixed primary color measurement chart in the first embodiment. [Figure 10] FIG. 10 is a flowchart showing the flow of the mixed primary color gradation correction parameter information generation process according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the functional configuration of a DFE according to the second embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a user interface according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of an image processing apparatus, an image processing method, and a program will be described in detail with reference to the accompanying drawings. Note that the image forming apparatus described below may be an inkjet image forming apparatus or an electrophotographic image forming apparatus.

[0011] (First embodiment) The first embodiment will be described below with reference to FIGS.

[0012] [Explanation of the image processing system configuration] FIG. 1 is a diagram showing an example of an image processing system 100 according to the first embodiment.

[0013] As shown in FIG. 1, the image processing system 100 includes a computer 200, a DFE (Digital Front End) 300, and an image forming apparatus 400.

[0014] The computer 200 is a device that allows a user to create a print job that includes image data to be executed by the image forming device 400 , and transmits the created print job to the DFE 300 .

[0015] The DFE 300 performs predetermined image processing on image data based on a print job received from the computer 200 and supplies the image data to the image forming apparatus 400. The DFE 300 is communicably connected to the image forming apparatus 400. The DFE 300 is an example of an image processing apparatus.

[0016] The image forming device 400 prints, on a predetermined print medium, an image or the like corresponding to image data that has undergone predetermined image processing in the DFE 300. The image forming device 400 is equipped with normal colorants, which are the CMYK process colors of C (cyan), M (magenta), Y (yellow), and K (black), and light colorants, which have the same hue as the process colors but a lighter density than the process colors. The light colorants are also referred to as light inks or light inks, for example. The image forming device 400 is equipped with, for example, a light cyan colorant corresponding to cyan, and a gray colorant corresponding to black. The light colorants have a maximum saturation intermediate between the corresponding normal colorants.

[0017] The image forming apparatus 400 forms an image on a recording medium by mixing normal color materials and light color materials. More specifically, the image forming apparatus 400 forms an image on a recording medium using a mixed primary color expressed by outputting a combination of normal color materials and light color materials. This improves the graininess of light colors, such as human skin and the color of the sky, compared to when an image is formed using only normal color materials.

[0018] In the present embodiment, the DFE 300 and the image forming apparatus 400 are shown as different apparatuses, but this is not limiting, and the image forming apparatus 400 may have the functions of the DFE 300, or the image forming apparatus 400 may have the functions of the DFE 300. For example, if the computer 200 has the functions of the DFE 300, a configuration equivalent to the functions of the DFE 300 can be understood as an image processing apparatus. Furthermore, the functions of the DFE 300 may be shared between the computer 200 and the image forming apparatus 400.

[0019] FIG. 2 is a diagram illustrating an example of a hardware configuration of the DFE 300a according to the first embodiment.

[0020] 2, the DFE 300a includes a central processing unit (CPU) 301, which serves as a control unit. The DFE 300a includes a read-only memory (ROM) 302, a random access memory (RAM) 303, a hard disk drive (HDD) 304, a solid state drive (SSD) 305, an interface (I / F) 306, a liquid crystal display (LCD) 307, and an operation unit 308, and each unit is connected to the CPU 301 via a bus 309.

[0021] The CPU 301 uses the RAM 303 as a work area and executes programs stored in the ROM 302, HDD 304, SSD 305, etc., to control the image forming apparatus 400 and perform image processing. The HDD 304 and SSD 305 function as a recording unit 315 that stores print jobs and the like sent from the computer 200. They may also store programs executed by the CPU 301. The I / F 306 communicatively connects the CPU 301, the HDD 304, the SSD 305, etc., to the LCD 307 and the operation unit 308. The LCD 307 is an example of a display unit that outputs information to the user. The operation unit 308 is a device such as a touch panel, keyboard, or mouse that the user uses to select information displayed on the LCD 307 or to operate the DFE 300a.

[0022] [Explanation of the DFE functional configuration] FIG. 3 is a diagram illustrating an example of the functional configuration of the DFE 300a according to the first embodiment.

[0023] The DFE 300a includes a print image generation unit 311, a tone correction processing unit 312, a halftone processing unit 313, a tone correction parameter generation unit 314, and a recording unit 315. The functions of these functional units are realized by the CPU 301 executing a program stored in the ROM 302 or the like.

[0024] The print image generation unit 311 performs color conversion processing using a color profile on the image data supplied from the computer 200, generating image data for each color material provided in the image forming device 400. The print image generation unit 311 also determines the print amount of normal color material and light color material for each pixel. This "print amount" is the amount of color material fixed per unit area on the print medium when the image forming device 400 prints. For example, in areas where the print amount is 100%, the color material is fixed without any gaps. In areas where the print amount is 0%, no color material is fixed at all.

[0025] The gradation correction processing unit 312 performs gradation correction processing to correct the print amount of each pixel of the image data generated by the print image generation unit 311 to a value that absorbs fluctuations in the image forming device 400, using gradation correction parameters for each color that are stored in advance in the recording means 315. Such gradation correction processing performed in the gradation correction processing unit is also called calibration.

[0026] The halftone processing unit 313 performs screen processing on the image data corrected by the gradation correction processing unit 312 to form color gradations by adjusting the number and density of color points (color lines) so that the image data is in a format suitable for the output capabilities of the image forming device 400, and then supplies the result to the image forming device 400.

[0027] The tone correction parameter generating unit 314 generates tone correction parameters for each color used by the tone correction processing unit 312 based on the tone characteristics of the image forming apparatus 400 during printing, and stores them in the recording means 315 .

[0028] FIG. 4 is a diagram showing an example of the functional configuration of the tone correction parameter generating unit 314 according to the first embodiment.

[0029] As shown in FIG. 4, the gradation correction parameter generation unit 314 includes a single color gradation correction parameter generation unit 321 and a mixed primary color gradation correction parameter generation unit 322.

[0030] The single-color gradation correction parameter generation unit 321 generates single-color gradation correction parameters for normal color materials and light-color color materials. The single-color gradation correction parameters are used to correct the gradation characteristics of the normal color materials and light-color color materials. Hereinafter, the process of generating single-color gradation correction parameters may be referred to as a single-color gradation correction parameter generation process.

[0031] Specifically, the single color gradation correction parameter generation unit 321 has a single color gradation correction chart output processing unit 331 and a single color gradation correction processing unit 332 .

[0032] The single-color gradation correction chart output processing unit 331 generates image data of a single-color measurement chart that expresses the gradation of each of the normal color material and the light color material, and outputs the image data to the image forming device 400.

[0033] FIG. 5 is a diagram showing an example of the layout of a single-color measurement chart according to the first embodiment.

[0034] As shown in FIG. 5, for example, when the image forming device 400 is equipped with gray as a light color material corresponding to black as a normal color material, the single-color gradation correction chart output processing unit 331 generates a patch pattern formed using CMYK color materials and a patch pattern formed using gray color materials.

[0035] Specifically, the single-color gradation correction chart output processing unit 331 generates patch patterns for each color material in stages, with a predetermined gradation value range, from the gradation value (lower limit) at which the print amount is 0% to the gradation value (upper limit) at which the print amount is 100%. For example, the single-color measurement chart shown in FIG. 5 has 21 patch patterns arranged for each color material.

[0036] The single-color gradation correction processing unit 332 acquires single-color gradation measurement information from data obtained by measuring each patch pattern printed on a printing medium in the image forming apparatus 400 using a spectrophotometer or the like. The single-color gradation measurement information includes, for example, information about the spectral reflectance of each patch pattern. The single-color gradation correction processing unit 332 calculates color information for normal colorants and light-color colorants based on the single-color gradation measurement information, and generates gradation characteristic information for each normal colorant and light-color colorant based on the calculated color information. The single-color gradation correction processing unit 332 uses the gradation characteristic information to generate single-color gradation correction parameter information for each colorant such that the gradation characteristics of the normal colorant and light-color colorant match the shape of the correction target information previously stored in the recording unit 315.

[0037] The correction target information refers to information that stores the target numerical values ​​for the post-correction gradation characteristics during calibration for each gradation value, and is stored in advance in the recording means 315 before the single-color gradation correction parameter generation process is executed.

[0038] Here, a method for generating single color gradation correction parameters generated by the single color gradation correction processing unit 332 will be described with reference to FIG.

[0039] Fig. 6 is a diagram illustrating a method for generating a single color gradation correction parameter according to the first embodiment. Fig. 6(a) is a diagram illustrating the relationship between gradation value (horizontal axis) and gradation characteristic information (vertical axis). In Fig. 6(a), the solid line indicates gradation characteristic information generated based on single color gradation measurement information, and the dashed line indicates correction target information. Fig. 6(b) is a diagram illustrating the relationship between input gradation value (horizontal axis) and output gradation value (vertical axis). Fig. 6(b) shows the single color gradation correction parameter information that is finally generated.

[0040] The arrows in Figure 6(a) indicate the process of generating single-color gradation correction parameters. In Figure 6(a), the value of the gradation characteristic information that is equivalent to the correction target value of 20% gradation value is 37%. In other words, to achieve the correction target gradation value of 20%, it is sufficient to actually print with a print volume of 37% as the input value. By calculating this correspondence relationship for all gradation values, the single-color gradation correction parameter information shown in the graph in Figure 6(b) is formed.

[0041] 4, the mixed primary color gradation correction parameter generation unit 322 generates a gradation correction parameter of the mixed primary color. Hereinafter, the process of generating a gradation correction parameter of the mixed primary color may be referred to as a mixed primary color gradation correction parameter generation process. Note that the above-mentioned single color gradation correction parameter generation process is performed as part of the mixed primary color gradation correction parameter generation process.

[0042] Specifically, the mixed primary color gradation correction parameter generation unit 322 has a mixed primary color gradation correction chart output processing unit 333 and a mixed primary color gradation correction processing unit 334 .

[0043] The mixed primary color gradation correction chart output processing unit 333 generates a mixed primary color measurement chart that expresses the gradation of the mixed primary color, and outputs it to the image forming device 400.

[0044] FIG. 7 is a diagram showing an example of the functional configuration of the mixed primary color gradation correction chart output processing unit 333 according to the first embodiment.

[0045] As shown in FIG. 7, the mixed primary color gradation correction chart output processing unit 333 includes a modulation point specifying unit 341 and a chart generating unit 342.

[0046] The modulation point identification unit 341 identifies the gradation value of the mixed primary color when the output of the normal color material starts in the mixed primary color as the modulation point, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that make up the mixed primary color.

[0047] FIG. 8 is a diagram illustrating an example of a conversion table according to the first embodiment.

[0048] 8 shows the relationship between the input gradation value of the mixed primary color (horizontal axis) and the output gradation values ​​of the normal color material and the light color material (vertical axis) when black is expressed as a mixed primary color by mixing black as a normal color material and gray as a light color material. Such a conversion table is generated in advance before the mixed primary color gradation correction parameter generation process and is stored in the recording means 315 as conversion table information.

[0049] For example, in the example of Figure 8, when the input tone value of black as a mixed primary color is 25%, the output tone value of black as a normal color material is 0%, and the output tone value of gray as a light color material is 50%. For example, when the input tone value of black as a mixed primary color is 50%, the output tone value of black as a normal color material is 0%, and the output tone value of gray as a light color material is 100%. For example, when the input tone value of black as a mixed primary color is 75%, the output tone value of black as a normal color material is 50%, and the output tone value of gray as a light color material is 50%. In this way, when the input tone value of the mixed primary color is small, only gray, which is a light color material, is output, and as the input tone value of the mixed primary color increases, the output of black, which is a normal color material, increases.

[0050] Based on this conversion table, the modulation point specifying unit 341 specifies, as the modulation point Ec, the input gradation value of black as the mixed primary color when the output of black, a normal color material, begins with respect to gray, a light color material. That is, at the modulation point Ec, the mixed primary color begins to output black, a normal color material, from the output of only gray, a light color material. In the example of FIG. 8, the modulation point Ec is 50%.

[0051] The chart generation unit 342 generates image data of a mixed primary color measurement chart that expresses the gradation of the mixed primary color, and outputs the image data to the image forming device 400.

[0052] FIG. 9 is a diagram showing an example of the layout of the mixed primary color measurement chart according to the first embodiment.

[0053] As shown in FIG. 9, for example, if the image forming device 400 is equipped with gray as a light color material corresponding to black as a normal color material, the chart generation unit 342 generates a patch pattern of a mixed primary color that is a mixture of black and gray.

[0054] Specifically, the chart generating unit 342 generates patch patterns P1 to P21 of mixed primary colors in stages in order of tone value in a predetermined tone value range by outputting black as a normal color material and gray as a light color material.

[0055] Furthermore, the chart generating unit 342 generates a patch pattern PEc corresponding to the modulation point Ec in addition to the patch patterns P1 to P21. The chart generating unit 342 arranges the patch pattern PEc between the patch patterns P11 and P12 according to the gradation value. In this way, a mixed primary color measurement chart is generated as a correction chart.

[0056] Like the other patch patterns P1 to P21, patch pattern PEc is used to generate gradation correction parameters for the mixed primary color in the mixed primary color gradation correction processing unit 334, which will be described later. By performing gradation correction processing based on the gradation correction parameters for the mixed primary color generated using such a mixed primary color measurement chart, it is possible to improve the accuracy of calibration when transitioning from the output of gray, which is a light color material, to black, which is a normal color material.

[0057] At this time, the single-color gradation correction parameters generated by the single-color gradation correction parameter generation unit 321 are applied to the black as a normal color material and the gray as a light color material output in generating the patch patterns P1 to P21 and the patch pattern PEc. That is, calibration is performed on each of the black as a normal color material and the gray as a light color material. This corrects density variations in single-color units of each color material.

[0058] 8, if the image forming device 400 is equipped with only gray colorants as light colorants, only patch patterns of mixed primary colors obtained by mixing black and gray will be arranged on the mixed primary color measurement chart. Normal colorants for which no corresponding light colorants exist are not included in the measurement chart because the single color gradation correction processing unit 332 has already completed the single color gradation correction parameter generation process.

[0059] The mixed primary color gradation correction processing unit 334 acquires mixed primary color gradation measurement information from data obtained as a result of measuring each patch pattern printed on a printing medium by the image forming device 400 using a spectrophotometer or the like. The mixed primary color gradation correction processing unit 334 generates gradation characteristic information of the mixed primary color based on the mixed primary color gradation measurement information. Using the gradation characteristic information, the mixed primary color gradation correction processing unit 334 generates mixed primary color gradation correction parameter information that matches the gradation characteristic of the mixed primary color with the shape of the correction target information stored in advance in the recording unit 315.

[0060] The mixed primary color gradation correction processing unit 334 stores the generated mixed primary color gradation correction parameters in the recording means 315 as mixed primary color gradation correction parameter information.

[0061] The mixed primary color gradation correction parameter information stored in the recording means 315 is used for the gradation correction process in the gradation correction processing unit. In this way, calibration of the mixed primary color can be performed. In this way, in addition to calibration in single color units of normal color materials and light color materials, calibration is also performed for the mixed primary color obtained by mixing normal color materials and light color materials, thereby improving correction accuracy.

[0062] FIG. 10 is a flowchart showing the flow of the mixed primary color gradation correction parameter generation process according to the first embodiment.

[0063] As described above, the single-color gradation correction parameter generation process is performed as a part of the mixed primary color gradation correction parameter generation process. That is, after the single-color gradation correction parameter is generated, the mixed primary color gradation correction parameter generation process is performed using the generated single-color gradation correction parameter.

[0064] As part of the mixed primary color gradation correction parameter generation process, first, the single color gradation correction chart output processing unit 331 generates a single color measurement chart that represents the gradation of each of the normal color material and the light color material, and outputs it to the image forming device 400 (step S1).

[0065] Next, the single color gradation correction processing unit 332 acquires single color gradation measurement information of each patch pattern of the single color measurement chart (step S2).

[0066] Next, the single color gradation correction processing unit 332 generates single color gradation correction parameter information based on the single color gradation measurement information (step S3). Note that the processes of S1 to S3 correspond to monotone gradation correction parameter generation processing.

[0067] Next, the mixed primary color gradation correction chart output processing unit 333 generates a mixed primary color measurement chart in the processes of steps S4 to S6.

[0068] The modulation point specifying unit 341 specifies, based on the conversion table, a modulation point Ec, which is the gradation value of the mixed primary color when output of the normal color material starts in the mixed primary color (step S4).

[0069] The chart generation unit 342 generates patch patterns P1 to P21 in which the gradation values ​​are gradually changed by a predetermined width using mixed primary colors obtained by mixing normal color materials and light color materials, each of which has been applied with a single-color gradation correction parameter. The chart generation unit 342 generates a mixed primary color measurement chart by adding a patch pattern PEc corresponding to the modulation point Ec to the patch patterns P1 to P21 (step S5).

[0070] Next, the mixed primary color gradation correction chart output processing unit 333 outputs the generated mixed primary color measurement chart to the image forming apparatus 400 (step S6).

[0071] Next, the mixed primary color gradation correction processing unit 334 acquires mixed primary color gradation measurement information of each patch pattern of the mixed primary color measurement chart (step S7).

[0072] Next, the mixed primary color gradation correction processing unit 334 generates mixed primary color gradation correction parameter information based on the acquired mixed primary color gradation measurement information (step S8).

[0073] The light color mixed gradation correction processing unit stores the generated mixed primary color gradation correction parameters in the recording means 315 (step S9). This completes the mixed primary color gradation correction parameter generation process.

[0074] As described above, according to this embodiment, the DFE 300 generates single color correction parameters for normal color materials and light color materials, and generates mixed primary color correction parameters using the normal color materials and light color materials to which the single color correction parameters have been applied. This makes it possible to perform calibration on a single color basis and calibration for mixed primary colors together, thereby improving the calibration accuracy of mixed primary colors.

[0075] Here, in the past, in mixed primary colors, the area where the light color material switches to the normal color material is the point where the two types of color materials start to mix, so it has been said that tone differences due to engine fluctuations are likely to occur.

[0076] According to this embodiment, the DFE 300 identifies a gradation in the mixed primary color where the light color material switches to the normal color material, and generates a patch pattern corresponding to this gradation. The DFE 300 generates mixed primary color correction parameters from data obtained by measuring such patch patterns. In this way, the mixed primary color correction parameters in the area where the light color material switches to the normal color material can be generated based on actual measurement results, thereby improving calibration accuracy and, as a result, making it possible to suppress gradation steps due to actual engine fluctuations.

[0077] (Second embodiment) The second embodiment will be described below with reference to FIGS.

[0078] The image processing system of the second embodiment differs from the above-described embodiments in that the DFE has a function of determining whether generation of a mixed primary color gradation correction parameter is necessary. Note that, in the following, the same components as those in the above-described embodiments are denoted by the same reference numerals, and their description may be omitted.

[0079] [Explanation of the DFE functional configuration] FIG. 11 is a diagram illustrating an example of the functional configuration of a DFE 300b according to the second embodiment.

[0080] The DFE 300b includes a print image generation unit 311, a tone correction processing unit 312, a halftone processing unit 313, a tone correction parameter generation unit 314, a recording unit 315, and a mixed primary color tone correction parameter generation determination unit 316.

[0081] The mixed primary color gradation correction parameter generation determining unit 316 determines, based on the image data received from the computer 200, whether or not it is necessary to generate mixed primary color gradation correction parameters.

[0082] Specifically, the mixed primary color gradation correction parameter generation determination unit 316 determines whether or not it is necessary to generate a mixed primary color gradation correction parameter based on (1) the proportion of a specific normal color material contained in the image data. For example, the mixed primary color gradation correction parameter generation determination unit 316 determines that it is necessary to generate a mixed primary color gradation correction parameter when n% of the image data contains a region containing a normal color material corresponding to a light color material.

[0083] Furthermore, the mixed primary color gradation correction parameter generation determination unit 316 determines whether or not it is necessary to generate mixed primary color gradation correction parameters based on (2) the date on which the last calibration was performed. For example, the mixed primary color gradation correction parameter generation determination unit 316 determines that it is necessary to generate mixed primary color gradation correction parameters when n days have passed since the last mixed primary color gradation correction parameter was generated.

[0084] When it is determined that generation of a mixed primary color gradation correction parameter is necessary, the mixed primary color gradation correction parameter generation determination unit 316 executes control to display a screen that guides the user to generate a mixed primary color gradation correction parameter (to execute calibration) on the user interface 500. The user interface 500 also functions as the LCD 307.

[0085] Fig. 12 is a diagram showing an example of a user interface according to the second embodiment. Specifically, when the mixed primary color gradation correction parameter generation determination unit 316 determines that generation of a mixed primary color gradation correction parameter is necessary in both of the above-mentioned (1) and (2), it executes control to display the pop-up window of Fig. 12 on the LCD 307 at the timing when image data is input to the DFE 300b and a print command of the computer 200 is executed by a user operation.

[0086] This allows users to operate the image processing device by performing conventional calibration on a regular basis, and only need to perform calibration for mixed primary colors when printing necessary image data. Users can more effectively suppress tone differences by performing the minimum amount of calibration required.

[0087] Furthermore, a program for executing the functions of each embodiment of the present invention is provided in advance in a ROM, etc. The program executed by the image forming apparatus of each embodiment may be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk).

[0088] Furthermore, the programs executed by the image forming apparatus of each embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.Furthermore, the programs executed by the image forming apparatus of each embodiment may be provided or distributed via a network such as the Internet.

[0089] The program executed by the image forming device of each embodiment is a modular structure including the above-mentioned units (print image generation unit, gradation correction processing unit, halftone processing unit, gradation correction parameter generation unit), and in actual hardware, the CPU (processor) reads and executes the program from the above-mentioned ROM, thereby loading the above-mentioned units onto the main memory, and the print image generation unit, gradation correction processing unit, halftone processing unit, and gradation correction parameter generation unit are generated on the main memory.

[0090] The aspects of the present invention are as follows. <1> An image processing device that is communicably connected to an image forming device that includes a normal color material and a light color material that has the same hue as the normal color material but a lower density than the normal color material, a single-color gradation correction parameter generating means for generating single-color correction parameters to be used for correcting the gradation characteristics of each of the normal color material and the light-color color material from data obtained by measuring patch patterns formed using each of the normal color material and the light-color color material; a mixed primary color gradation correction parameter generating means for generating mixed primary color correction parameters to be used for correcting gradation characteristics of the mixed primary color from data obtained by measuring a patch pattern formed using a mixed primary color output by applying the single color correction parameters to the normal color material and the light color material, The mixed primary color gradation correction parameter generating means a modulation point specifying means for specifying, as a modulation point, a gradation value of the mixed primary color at which output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that constitute the mixed primary color; and a chart generating means for generating a correction chart by adding a patch pattern corresponding to the modulation point to the patch pattern of the mixed primary color formed in stages with a predetermined gradation value width. <2> An image processing method executed by an image processing device, comprising: The image processing device includes: An image processing device that is communicably connected to an image forming device that includes a normal color material and a light color material that has the same hue as the normal color material but a lower density than the normal color material, generating single-color correction parameters to be used for correcting the gradation characteristics of each of the normal color material and the light-color color material from data obtained by measuring patch patterns formed using each of the normal color material and the light-color color material; and generating a mixed primary color correction parameter used to correct the gradation characteristics of the mixed primary color from data obtained by measuring a patch pattern formed using the mixed primary color output by applying the single color correction parameter to the normal color material and the light color material, The step of generating the mixed primary color correction parameters includes: specifying, as a modulation point, a gradation value of the mixed primary color at which output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that constitute the mixed primary color; generating a correction chart by adding patch patterns corresponding to the modulation points to the patch patterns of the mixed primary colors formed in stages with a predetermined gradation value width; An image processing method comprising: <3> A program to be executed by a computer of an image processing device, The image processing device includes: An image processing device that is communicably connected to an image forming device that uses a normal color material and a light color material that has the same hue as the normal color material but a lower density than the normal color material, generating single-color correction parameters to be used for correcting the gradation characteristics of each of the normal color material and the light-color color material from data obtained by measuring patch patterns formed using each of the normal color material and the light-color color material; and generating a mixed primary color correction parameter used to correct the gradation characteristics of the mixed primary color from data obtained by measuring a patch pattern formed using the mixed primary color output by applying the single color correction parameter to the normal color material and the light color material, The step of generating the mixed primary color correction parameters includes: specifying, as a modulation point, a gradation value of the mixed primary color at which output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that constitute the mixed primary color; generating a correction chart by adding patch patterns corresponding to the modulation points to the patch patterns of the mixed primary colors formed in stages with a predetermined gradation value width; A program that causes a computer to execute the following. [Explanation of symbols]

[0091] 100 Image Processing System 200 computers 300 DFE 312 Tone Correction Processing Unit 314 Tone Correction Parameter Generation Unit 321 Single color gradation correction parameter generation unit 322 Mixed Primary Color Tone Correction Parameter Generation Unit 333 Mixed primary color gradation correction chart output processing section 334 Mixed primary color gradation correction processing section 341 Modulation point identification unit 342 Chart Generation Unit 400 Image forming device [Prior art documents] [Patent documents]

[0092] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-189789 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-093957

Claims

1. An image processing device that is communicably connected to an image forming device that includes a normal color material and a light color material that has the same hue as the normal color material but a lower density than the normal color material, a single-color gradation correction parameter generating means for generating single-color correction parameters to be used for correcting the gradation characteristics of each of the normal color material and the light-color color material from data obtained by measuring patch patterns formed using each of the normal color material and the light-color color material; a mixed primary color gradation correction parameter generating means for generating mixed primary color correction parameters to be used for correcting gradation characteristics of the mixed primary colors from data obtained by measuring a patch pattern formed using mixed primary colors output by applying the single color correction parameters to the normal color material and the light color material; Equipped with The mixed primary color gradation correction parameter generating means a modulation point specifying means for specifying, as a modulation point, a gradation value of the mixed primary color at which output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that constitute the mixed primary color; a chart generating means for generating a correction chart by adding patch patterns corresponding to the modulation points to the patch patterns of the mixed primary colors formed in stages with a predetermined gradation value width; having Image processing device.

2. An image processing method executed by an image processing device, comprising: The image processing device includes: An image processing device that is communicably connected to an image forming device that includes a normal color material and a light color material that has the same hue as the normal color material but a lower density than the normal color material, generating single-color correction parameters to be used for correcting the gradation characteristics of each of the normal color material and the light-color color material from data obtained by measuring patch patterns formed using each of the normal color material and the light-color color material; generating a mixed primary color correction parameter to be used for correcting the gradation characteristics of the mixed primary color from data obtained by measuring a patch pattern formed using the mixed primary color output by applying the single color correction parameter to the normal color material and the light color material; Equipped with The step of generating the mixed primary color correction parameters includes: specifying, as a modulation point, a gradation value of the mixed primary color at which output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that constitute the mixed primary color; generating a correction chart by adding patch patterns corresponding to the modulation points to the patch patterns of the mixed primary colors formed in stages with a predetermined gradation value width; An image processing method comprising:

3. A program to be executed by a computer of an image processing device, The image processing device includes: An image processing device that is communicably connected to an image forming device that uses a normal color material and a light color material that has the same hue as the normal color material but a lower density than the normal color material, generating single-color correction parameters to be used for correcting the gradation characteristics of each of the normal color material and the light-color color material from data obtained by measuring patch patterns formed using each of the normal color material and the light-color color material; generating a mixed primary color correction parameter to be used for correcting the gradation characteristics of the mixed primary color from data obtained by measuring a patch pattern formed using the mixed primary color output by applying the single color correction parameter to the normal color material and the light color material; Equipped with The step of generating the mixed primary color correction parameters includes: specifying, as a modulation point, a gradation value of the mixed primary color at which output of the normal color material in the mixed primary color starts, based on a conversion table that associates the gradation value of the mixed primary color with the gradation values ​​of the normal color material and the light color material that constitute the mixed primary color; generating a correction chart by adding patch patterns corresponding to the modulation points to the patch patterns of the mixed primary colors formed in stages with a predetermined gradation value width; A program that causes a computer to execute the following.

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