Image processing device, image processing method, and program

Abstract

To provide an image processing apparatus, an image processing method, and program that can facilitate generation of image data when a fluorescent color different from a process color is used.SOLUTION: An image processing apparatus comprises: a first acquisition unit that acquires first image data to be subjected to color conversion; and a color conversion unit that, based on the dot area ratio of any one color of process colors indicated by the first image data, converts the first image data acquired by the first acquisition unit into second image data in which the dot area ratio is divided into the dot area ratio of a fluorescent color different from the process color and the dot area ratio of the process color.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] Generally, images printed in process colors using subtractive color mixing on copiers and printers have a narrower color reproduction gamut than images printed using additive color mixing on displays. Since process color reproduction is based on subtractive color mixing, the more color materials are layered in an attempt to produce a vivid color, the lower the brightness and the duller the color becomes. Therefore, in order to expand the color reproduction gamut and improve the hue, color materials have been explored and fluorescent materials have been used. Here, process colors refer to the four plates C (cyan), M (magenta), Y (yellow), and K (black). It is expected that subtractive color mixing using fluorescent color materials (fluorescent inks, fluorescent toners, etc.) with added fluorescent materials can reproduce colors with higher brightness and saturation than those without added fluorescent materials (CMYK process colors), and expand the color reproduction gamut.

[0003] For example, fluorescent magenta is a typical fluorescent ink. Figure 17 shows the spectral distribution characteristics of fluorescent magenta (hereinafter sometimes written as "NM" (Neon Magenta)) and process color magenta (hereinafter sometimes written as "M"), and lists their features. The first feature is that the two inks have absorption spectrum peaks in roughly the same band. The second feature is that NM ink has a fluorescent spectrum peak on the longer wavelength side of the absorption spectrum peak.

[0004] In the market, fluorescent ink is being used in offset printers and fluorescent toner is being used in electrophotography. In the case of offset printers, there are cases where an ink is made by adding fluorescent magenta to magenta in advance and using it instead of magenta ink. In this case, image data can be created with the same process colors as before. On the other hand, electrophotography machines handle toner one color at a time, so in addition to the process colors, image data requires a fifth plate for fluorescent magenta. In electronic submission, the submission condition is that the data can be passed on to the printing process without processing, correction, adjustment, etc. at the printing company where the data is submitted, so the designer who submitted the data must create the fifth plate. However, creating the fifth plate by oneself using limited applications is a big burden. Therefore, a function is desired that allows image data submitted in four plates to be easily decomposed into five plates at the time of printing, and that allows easy specification of printable colors with fluorescent toner added.

[0005] As a technology that utilizes colorants other than such process colors, a technology has been disclosed in which, when the process colors CMYK are decomposed into CMYK, LC (light cyan), and LM (light magenta), LC (light cyan) ink is added so that it is at its maximum in the mid-tone range (around 75 to 95%) where C (cyan) ink increases, and then reduced in the high saturation range (above 95%) in order to reduce density unevenness (for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0006] However, using fluorescent colorants of the same color type instead of process colors as in conventional technology has the advantage that the colors do not sink, but there is a problem that a color conversion algorithm cannot be constructed because there is no color measurement standard and color values ​​cannot be defined. Also, for this reason, when creating image data, it is common to manually create fluorescent plates, which requires skill when creating images.

[0007] 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 can facilitate the creation of image data when using fluorescent colors different from process colors. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the present invention provides an image processing apparatus comprising: a first acquisition unit that acquires first image data to be subjected to color conversion; and a color conversion unit that converts the first image data acquired by the first acquisition unit into second image data in which the dot area rate of a fluorescent color different from the process color and the dot area rate of the process color are distributed based on the dot area rate of one of the process colors indicated by the first image data. The color conversion unit calculates the dot area ratio of the one color and the dot area ratio of the fluorescent color by using a distribution ratio having a positive correlation with the saturation calculated based on the dot area ratio of the process color of the first image data. It is characterized by: Effect of the Invention

[0009] According to the present invention, it is possible to easily create image data when using fluorescent colors different from process colors. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a system including an image forming apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of the image forming apparatus according to the first embodiment. [Diagram 3] FIG. 3 is a diagram illustrating an example of the functional block configuration of the controller of the image forming apparatus according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a functional block configuration of a color conversion unit of a controller of the image forming apparatus according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing an example of a BtoA table of a four-color profile. [Figure 6] FIG. 6 is a diagram showing an example of a BtoA table of a five-color profile. [Figure 7]FIG. 7 is a diagram showing an example of an AtoB table of a four-color profile. [Figure 8] FIG. 8 is a diagram showing an example of an AtoB table of a five-color profile. [Figure 9] FIG. 9 is a flowchart showing an example of the flow of a process for generating a five-color profile of the image forming apparatus according to the first embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of the flow of print processing in the image forming apparatus according to the first embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of the flow of color conversion processing in the print processing of the image forming apparatus according to the first embodiment. [Figure 12] FIG. 12 is a graph showing the relationship between saturation and distribution rate. [Figure 13] FIG. 13 is a diagram illustrating an example of the functional block configuration of a controller of an image forming apparatus according to the third embodiment. [Figure 14] FIG. 14 is a diagram showing an example of the spot color dictionary. [Figure 15] FIG. 15 is a flowchart showing an example of the flow of a spot color dictionary creation process of the image forming apparatus according to the third embodiment. [Figure 16] FIG. 16 is a flowchart showing an example of the flow of print processing in the image forming apparatus according to the third embodiment. [Figure 17] FIG. 17 is a diagram showing the spectral distribution characteristics of fluorescent magenta and process color magenta. [Figure 18] FIG. 18 is a diagram illustrating an example of the functional block configuration of a color conversion unit of a controller of an image forming apparatus according to the fourth embodiment. [Figure 19] FIG. 19 is a diagram showing an example of a BtoA table of a pre-change five-color profile. [Figure 20] FIG. 20 is a diagram showing an example of a BtoA table of a changed five-color profile. [Figure 21] FIG. 21 is a diagram showing an example of the AtoB table of the pre-change five-color profile. [Figure 22] FIG. 22 is a diagram showing an example of the AtoB table of the changed five-color profile. [Diagram 23] FIG. 23 is a graph showing an example of the relationship between saturation and distribution rate. [Figure 24] FIG. 24 is a graph showing another example of the relationship between saturation and distribution ratio. [Diagram 25] FIG. 25 is a flowchart showing an example of the flow of a process for generating a changed five-color profile in an image forming apparatus according to the fourth embodiment. [Figure 26] FIG. 26 is a flowchart showing an example of the flow of color conversion processing in the print processing of the image forming apparatus according to the fourth embodiment. [Figure 27] FIG. 27 is a diagram illustrating an example of the functional block configuration of a color conversion unit of a controller of an image forming apparatus according to the fifth embodiment. [Figure 28] FIG. 28 is a diagram for explaining the operation of deriving chroma from cyan, magenta, yellow, and fluorescent magenta. [Figure 29] FIG. 29 is a flowchart showing an example of the flow of color conversion processing in print processing of the image forming apparatus according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of an image processing device, an image processing method, and a program according to the present invention will be described in detail with reference to the drawings. Furthermore, the present invention is not limited to the following embodiments, and the components in the following embodiments include those that a person skilled in the art can easily conceive, those that are substantially the same, and those that are within the scope of what is called equivalent. Furthermore, various omissions, substitutions, modifications, and combinations of the components can be made without departing from the spirit of the following embodiments.

[0012] [First embodiment] By mixing a small amount of fluorescent color with process color as in offset printing machines, even highly saturated colors can be used without dulling and give a vivid impression. In this case, since the visual impression is more important than the numerical accuracy of the color, for example, the device value of magenta can be allocated to magenta and fluorescent magenta. The actual color conversion is performed based on an ICC profile defined by the ICC (International Color Consortium). Note that many different color matching techniques, such as a method for creating a profile and a method for adjusting a color, have been disclosed as a means for color management of printed matter. These color matching techniques are not limited to electrophotographic printing machines, but can be applied across the board to all digital printers, including inkjet and thermal printers, and their peripheral devices. In this embodiment, an example of color conversion using a profile will be described in detail.

[0013] In this embodiment, the device value of magenta is distributed to calculate the device values ​​of magenta and fluorescent magenta in order to create a five-color profile. The five-color profile is composed of a source profile and a printer profile, and the source profile specifies the correspondence between Lab values ​​corresponding to the grid points of C, M, Y, K, and NM that are input, and the printer profile specifies the correspondence between C, M, Y, K, and NM values ​​corresponding to the grid points of L, a, and b that are input. Here, the Lab value is a color value in the Lab color space. The controller of the image forming apparatus according to this embodiment converts a CMYK image into a CMYK+NM image using the four-color profile and the five-color profile.

[0014] Furthermore, distribution also includes, for example, calculating the device values ​​of magenta and fluorescent magenta based on the device value of magenta.Specifically, when the device value of magenta before conversion is 1, it includes calculation so that (device value of magenta after conversion): (device value of fluorescent magenta after conversion) = 1 - α: α (0 < α < 1) (an example of a predetermined ratio), and also includes calculation and conversion of the device value of magenta and the device value of fluorescent magenta such that (device value of magenta after conversion): (device value of fluorescent magenta after conversion) = 1 - α: α + β (0 < α < 1, β: arbitrary value) (an example of a predetermined ratio).

[0015] Hereinafter, the embodiment will be described taking as an example a case where (device value of magenta after conversion): (device value of fluorescent magenta after conversion)=1-α:α (0<α<1).

[0016] (System including image forming device) Fig. 1 is a diagram showing an example of the configuration of a system including an image forming apparatus according to the first embodiment. The configuration of a system including an image forming apparatus 10 according to the present embodiment will be described with reference to Fig. 1.

[0017] 1 includes an image forming apparatus 10 and a PC (Personal Computer) 20. The image forming apparatus 10 and the PC 20 are capable of communicating with each other via a network N.

[0018] The image forming apparatus 10 is an apparatus that forms (prints) an image based on image data received from an external device or image data stored in its own storage device. The image forming apparatus 10 is, for example, an MFP (Multifunction Peripheral) and is an example of an image processing apparatus.

[0019] The PC 20 is an information processing device that transmits image data along with a print command for the image data created or selected in accordance with a user's operation to the image forming apparatus 10. Note that the PC 20 is not limited to being a PC, and may be, for example, an information processing device such as a smartphone, a tablet terminal, or a scanner device.

[0020] The system configuration shown in FIG. 1 is an example, and may include, for example, a print server that manages print jobs including image data output from the PC 20.

[0021] (Hardware configuration of image forming device) 2 is a diagram showing an example of a hardware configuration of the image forming apparatus according to the first embodiment. The hardware configuration of the image forming apparatus 10 according to the present embodiment will be described with reference to FIG.

[0022] As shown in FIG. 2, the image forming apparatus 10 according to this embodiment includes a controller 200, an operation display unit 210, an FCU (Facsimile Control Unit) 220, a plotter 231 (printing device), a scanner 232, and a colorimeter 233, all connected via a PCI (Peripheral Component Interface) bus.

[0023] The controller 200 is a device that controls the entire image forming apparatus 10 , and controls drawing, communication, and input from the operation display unit 210 .

[0024] The operation display unit 210 is, for example, a touch panel, and is a device that accepts input to the controller 200 (input function) and displays the status of the image forming apparatus 1 (display function), and is directly connected to an ASIC (Application Specific Integrated Circuit) 206 described later.

[0025] The FCU 220 is a device that realizes a fax function, and is connected to the ASIC 206 via, for example, a PCI bus.

[0026] The plotter 231 is a device that realizes a printing function, and is connected to the ASIC 206 via, for example, a PCI bus. The scanner 232 is a function that realizes a scanner function, and is connected to the ASIC 206 via, for example, a PCI bus. The colorimeter 233 is a device that measures the color of an image printed on a recording medium and obtains color values ​​in a device-independent color space (for example, Lab color space) as colorimetric values, and is connected to the ASIC 206 via, for example, a PCI bus.

[0027] The controller 200 has a CPU (Central Processing Unit) 201, a system memory (MEM-P) 202, a north bridge (NB) 203, a south bridge (SB) 204a, a network I / F 204b, a USB (Universal Serial Bus) I / F 204c, a Centronics I / F 204d, an ASIC 206, a local memory (MEM-C) 207, and an auxiliary storage device 208.

[0028] The CPU 201 performs overall control of the image forming apparatus 10, and is connected to a chip set consisting of a system memory 202, a north bridge 203, and a south bridge 204a, and is connected to other devices via this chip set.

[0029] The system memory 202 is used as a memory for storing programs and data, a memory for expanding programs and data, a memory for printer drawing, etc., and has a ROM (Read Only Memory) and a RAM (Random Access Memory). Of these, the ROM is a read-only memory used as a memory for storing programs and data, and the RAM is a writable and readable memory used as a memory for expanding programs and data, a memory for printer drawing, etc.

[0030] The north bridge 203 is a bridge for connecting the CPU 201 with the system memory 202, south bridge 204a, and AGP (Accelerated Graphics Port) bus 205, and includes a memory controller that controls reading and writing to the system memory 202, a PCI master, and an AGP target.

[0031] The south bridge 204a is a bridge for connecting the north bridge 203 with PCI devices and peripheral devices. The south bridge 204a is connected to the north bridge 203 via a PCI bus, and a network I / F 204b, a USB I / F 204c, a Centronics I / F 204d, and the like are connected to the PCI bus.

[0032] The AGP bus 205 is a bus interface for a graphics accelerator card proposed to accelerate graphic processing. The AGP bus 205 is a bus that accelerates the graphics accelerator card by directly accessing the system memory 202 at high throughput.

[0033] The ASIC 206 is an integrated circuit (IC) for image processing purposes having hardware elements for image processing, and serves as a bridge connecting the AGP bus 205, the PCI bus, the auxiliary storage device 208, and the local memory 207. The ASIC 206 is composed of a PCI target and an AGP master, an arbiter (ARB) that is the core of the ASIC 206, a memory controller that controls the local memory 207, a plurality of direct memory access controllers (DMACs) that perform image data rotation and the like using hardware logic, and a PCI unit that transfers data between the plotter 231 and the scanner 232 via the PCI bus. For example, the FCU 220, the plotter 231, the scanner 232, and the colorimeter 233 are connected to the ASIC 206 via the PCI bus. The ASIC 206 is also connected to a host PC (personal computer) and a network (not shown).

[0034] The local memory 207 is a memory used as an image buffer for copying and a code buffer.

[0035] The auxiliary storage device 208 is a storage device such as a hard disk drive (HDD), a solid state drive (SSD), a secure digital (SD) card, or a flash memory, and is a storage for storing image data, programs, font data, and forms, etc.

[0036] The program for the image forming apparatus 10 described above may be distributed by being recorded in a computer-readable recording medium (such as the auxiliary storage device 208) as a file in an installable or executable format.

[0037] In addition, the colorimeter 233 is assumed to perform data communication with the controller 200 via a PCI bus, but this is not limited to this, and data communication with the controller 200 may be possible via a network via the network I / F 204b.

[0038] Furthermore, the hardware configuration of the image forming apparatus 10 shown in FIG. 2 is merely an example, and it is not necessary for all of the components to be included, and other components may also be included.

[0039] (Configuration and operation of functional blocks of a controller of an image forming apparatus) FIG. 3 is a diagram showing an example of the configuration of functional blocks of a controller of an image forming apparatus according to the first embodiment. FIG. 4 is a diagram showing an example of the configuration of functional blocks of a color conversion unit of a controller of an image forming apparatus according to the first embodiment. FIG. 5 is a diagram showing an example of a BtoA table of a four-color profile. FIG. 6 is a diagram showing an example of a BtoA table of a five-color profile. FIG. 7 is a diagram showing an example of an AtoB table of a four-color profile. FIG. 8 is a diagram showing an example of an AtoB table of a five-color profile. The configuration and operation of functional blocks of a controller 200 of an image forming apparatus 10 according to this embodiment will be described with reference to FIGS. 3 to 8.

[0040] As shown in FIG. 3, the controller 200 of the image forming device 10 has a memory unit 301, a data input / output unit 302, a color conversion profile generation unit 303 (first generation unit), an image data acquisition unit 304 (first acquisition unit), a color conversion unit 305, and an image output unit 306.

[0041] The storage unit 301 is a functional unit that stores an ICC profile of four colors (four-color profile), an ICC profile of five colors (five-color profile) generated by the color conversion profile generation unit 303, etc. The storage unit 301 is realized by the auxiliary storage device 208 shown in FIG.

[0042] The data input / output unit 302 is a functional unit that reads data from the storage unit 301 and writes data to the storage unit 301. The data input / output unit 302 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0043] The color conversion profile generation unit 303 is a functional unit that receives a four-color profile from the storage unit 301 via the data input / output unit 302, distributes the device value of magenta (M) (an example of a homogeneous process color that is a spot color), calculates device values ​​of magenta (M) and fluorescent magenta (NM) (an example of a spot color, an example of a fluorescent color), and generates a five-color profile. Here, the device value indicates the dot area ratio, which is the ratio of the dot area per unit area.

[0044] The homochromatic process colors are process colors that have an absorption spectrum peak close to the absorption spectrum peak of the fluorescent color.

[0045] 5 shows a BtoA table of a four-color profile. Here, "BtoA" means conversion from Lab values ​​to CMYK values ​​(or CMYK+NM values), and "AtoB" described below means conversion to CMYK values ​​(or CMYK+NM values). In this embodiment, in order to generate a five-color profile, the color conversion profile generation unit 303 distributes the device value of magenta (M) in the four-color profile acquired from the storage unit 301 via the data input / output unit 302, and assigns a distribution rate that is a fixed value when calculating the device values ​​of magenta (M) and fluorescent magenta (NM). That is, when the CMYK values ​​corresponding to the Lab values ​​(Lab grid points) described in the BtoA table of the four-color profile as the printer profile are C=c (0≦c≦100), Y=y (0≦y≦100), and K=k (0≦k, ≦100), respectively, the color conversion profile generation unit 303 performs distribution only for magenta (M) and calculates the device value of fluorescent magenta (NM) as C=c, M=α×m (0≦m≦100), Y=y, K=k, and NM=(1-α)×m using a fixed distribution rate α. Here, the distribution rate α is 0<α<1, and ideally, α≈0.4 is appropriate. Then, the color conversion profile generation unit 303 performs the above-mentioned distribution of magenta (M) for all the Lab values ​​(Lab grid points) in the BtoA table of the four-color profile, and calculates the device values ​​of magenta (M) and fluorescent magenta (NM). Then, the color conversion profile generation unit 303 generates a BtoA table of the five-color profile shown in FIG. 6 by setting the CMYK+NM value corresponding to each Lab value (Lab lattice point).

[0046] Similarly, the color conversion profile generation unit 303 adds NM values ​​to each CMYK value (CMYK lattice point) described in the AtoB table of the four-color profile serving as the source profile shown in Fig. 7 to expand it to five colors, and calculates device values ​​for magenta (M) and fluorescent magenta (NM) in the same manner as the BtoA table described above.Then, the color conversion profile generation unit 303 generates the AtoB table of the five-color profile shown in Fig. 8 by setting each CMYK+NM value in the new AtoB table.

[0047] Here, the color conversion profile generation unit 303 rewrites only the device values ​​in both the BtoA table and the AtoB table, and does not rewrite the Lab values ​​that configure the PCS (Profile Connection Space).The color conversion profile generation unit 303 also rewrites the necessary tags when expanding from a 4-color profile to a 5-color profile.

[0048] The color transformation profile generation unit 303 stores the generated five-color profile in the storage unit 301 via the data input / output unit 302. The color transformation profile generation unit 303 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0049] The image data acquisition unit 304 is a functional unit that acquires CMYK image data (an example of first image data) from, for example, the PC 20 via the network N. The image data acquisition unit 304 sends the acquired CMYK image data to the color conversion unit 305. The image data acquisition unit 304 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0050] The color conversion unit 305 is a functional unit that acquires CMYK image data from the image data acquisition unit 304, acquires a four-color profile and a five-color profile from the storage unit 301 via the data input / output unit 302, and uses the acquired four-color profile and five-color profile to color convert the four-plate CMYK image data into five-plate CMYK+NM image data (an example of second image data) that depends on the printer (plotter 231). As the CMYK+NM image data, for example, color data created by changing the device values ​​of C, M, Y, K, and NM within the range of 0 to 100 may be used.

[0051] As shown in FIG. 4, the color conversion unit 305 includes a source profile conversion unit 3051 and a printer profile conversion unit 3052 .

[0052] The source profile conversion unit 3051 is a functional unit that acquires a four-color profile from the storage unit 301 via the data input / output unit 302, and converts the CMYK values ​​of each pixel constituting the four-plate CMYK image data acquired from the image data acquisition unit 304 into Lab values ​​using the four-color profile. The source profile conversion unit 3051 sends the converted Lab values ​​to a printer profile conversion unit 3052.

[0053] The printer profile conversion unit 3052 is a functional unit that acquires a five-color profile from the storage unit 301 via the data input / output unit 302, and converts the Lab values ​​received from the source profile conversion unit 3051 into five-plate image data consisting of CMYK+NM values ​​using the five-color profile. The printer profile conversion unit 3052 sends the converted five-plate CMYK+NM image data to the image output unit 306.

[0054] The color conversion unit 305 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0055] The image output unit 306 is a functional unit that outputs the CMYK+NM image data color-converted by the color conversion unit 305 to a printer (plotter 231) and causes the printer to execute printing. The image output unit 306 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0056] At least a part of the functional units of the controller 200 illustrated in FIG. 3 that are implemented by software (programs) may be implemented by a hardware circuit such as a field-programmable gate array (FPGA) or an ASIC.

[0057] Moreover, each functional unit of the controller 200 shown in Fig. 3 is shown conceptually, and is not limited to such a configuration. For example, a plurality of functional units illustrated as independent functional units in the controller 200 shown in Fig. 3 may be configured as one functional unit. On the other hand, the function of one functional unit in the controller 200 shown in Fig. 3 may be divided into a plurality of functional units and configured as a plurality of functional units.

[0058] (5-color profile generation process) 9 is a flowchart showing an example of the flow of a process for generating a five-color profile of the image forming apparatus according to the first embodiment. The flow of a process for generating a five-color profile of the image forming apparatus 10 according to the present embodiment will be described with reference to FIG.

[0059] <Step S11> First, the color transformation profile generation unit 303 acquires a four-color profile (first profile) from the storage unit 301 via the data input / output unit 302. Then, the process proceeds to step S12.

[0060] <Step S12> The color transformation profile generating unit 303 obtains a BtoA table (see, for example, FIG. 5) from the obtained four-color profile, and then proceeds to step S13.

[0061] <Step S13> The color conversion profile generating unit 303 extracts the CMYK values ​​as grid point information from the BtoA table of the acquired four-color profile, and then proceeds to step S14.

[0062] <Step S14> The color conversion profile generating unit 303 distributes the device value of magenta (M) from among the extracted CMYK values ​​to calculate device values ​​of magenta (M) and fluorescent magenta (NM), and then proceeds to step S15.

[0063] <Step S15> The color conversion profile generation unit 303 rewrites, for example, the CMYK values ​​in the BtoA table of the acquired four-color profile with CMYK+NM values ​​including the calculated device values ​​of magenta (M) and fluorescent magenta (NM), and then proceeds to step S16.

[0064] <Step S16> If the processing of steps S13 to S15 has been completed for all CMYK values ​​(lattice point information) in the BtoA table of the four-color profile acquired by the color conversion profile generation unit 303 (step S16: Yes), proceed to step S17, and if not completed (step S16: No), return to step S13. If the processing of steps S13 to S15 has been completed for all CMYK values ​​(lattice point information) in the BtoA table of the four-color profile acquired by the color conversion profile generation unit 303, a BtoA table of a five-color profile has been generated.

[0065] <Step S17> If the processes in steps S13 to S16 have already been performed on the AtoB table of the four-color profile (step S17: Yes), the process proceeds to step S19, and if not (step S17: No), the process proceeds to step S18.

[0066] <Step S18> The color transformation profile generating unit 303 obtains an AtoB table (see, for example, FIG. 7) from the obtained four-color profile. Then, the process returns to step S13.

[0067] <Step S19> In the above process, when the BtoA table and AtoB table of a five-color profile (second profile) are generated by the color conversion profile generation unit 303 for the BtoA table and AtoB table of a four-color profile, the color conversion profile generation unit 303 rewrites tags required for extension to a five-color profile. Then, the generation process of the five-color profile ends.

[0068] (Printing process of image forming device) Fig. 10 is a flowchart showing an example of the flow of print processing of the image forming apparatus according to the first embodiment. Fig. 11 is a flowchart showing an example of the flow of color conversion processing in print processing of the image forming apparatus according to the first embodiment. The flow of print processing of the image forming apparatus 10 according to this embodiment will be described with reference to Figs. 10 and 11. It is assumed that the five-color profile shown in Fig. 9 above has been generated in advance and stored in the storage unit 301.

[0069] <Step S21> First, when a user performs an operation to print image data via the operation display unit 210, the image data acquisition unit 304 acquires four CMYK image data via the network N. Then, the process proceeds to step S22.

[0070] <Step S22> The image forming apparatus 10 executes the color conversion process shown in Fig. 11. The color conversion process is performed in accordance with the following flow of steps S221 to S227.

[0071] <<Step S221>> The source profile conversion unit 3051 of the color conversion unit 305 acquires the four-plate CMYK image data acquired by the image data acquisition unit 304. Then, the process proceeds to step S222.

[0072] <<Step S222>> The source profile conversion unit 3051 acquires the four-color profile from the storage unit 301 via the data input / output unit 302. The printer profile conversion unit 3052 of the color conversion unit 305 acquires the five-color profile from the storage unit 301 via the data input / output unit 302. Then, the process proceeds to step S223.

[0073] <<Step S223>> The source profile conversion unit 3051 acquires four-plate CMYK image data from the image data acquisition unit 304. Next, the source profile conversion unit 3051 converts the CMYK values ​​of the pixels constituting the acquired four-plate CMYK image data into Lab values ​​using the acquired four-color profile (AtoB table). Then, the source profile conversion unit 3051 sends the converted Lab values ​​to the printer profile conversion unit 3052. Then, the process proceeds to step S224.

[0074] <<Step S224>> The printer profile conversion unit 3052 converts the Lab values ​​received from the source profile conversion unit 3051 into CMYK+NM values ​​using the acquired five-color profile (BtoA table), and replaces the target CMYK values ​​in the four-plate CMYK image data with the CMYK+NM values. Then, the process proceeds to step S225.

[0075] <<Step S225>> If conversion to and replacement with CMYK+NM values ​​has been completed for all pixels of the four CMYK image data (step S225: Yes), proceed to step S226; if processing has not been completed for all pixels (step S225: No), return to step S223.

[0076] <<Step S226>> The printer profile conversion unit 3052 generates image data in which all the CMYK values ​​of the pixels constituting the four-plate CMYK image data are replaced with CMYK+NM values, as five-plate CMYK+NM image data. The CMYK+NM values ​​constituting the five-plate CMYK+NM image data become device values ​​dependent on the printer (plotter 231). Then, the process proceeds to step S227.

[0077] <<Step S227>> The printer profile conversion unit 3052 sends the generated five-plate CMYK+NM image data to the image output unit 306. Then, the color conversion process ends, and the process proceeds to step S23 in FIG.

[0078] <Step S23> The image output unit 306 outputs the five-plate CMYK+NM image data color-converted by the color conversion unit 305 to a printer (plotter 231) and causes the printer to execute printing. Specifically, when the image data received from the color conversion unit 305 is for the fifth plate, the image output unit 306 confirms that the toner at the fifth station of the plotter 231 is fluorescent magenta, and when a different toner is loaded, for example, causes the operation display unit 210 to display a notice encouraging replacement of the toner bottle, etc. Also, when fluorescent magenta toner is loaded, the image output unit 306 outputs the five-plate CMYK+NM image data to the printer (plotter 231) and causes the printer to execute printing.

[0079] As described above, in the image forming apparatus 10 according to this embodiment, the color conversion profile generation unit 303 generates a five-color profile from a four-color profile, the color conversion unit 305 converts the four-plate CMYK image data into Lab values ​​using the four-color profile, and the five-color profile converts the Lab values ​​into CMYK+NM values, thereby converting the colors into five-plate CMYK+NM image data. This allows an algorithm for color conversion to be constructed, making it easy to create image data when fluorescent colorants are used.

[0080] In the above embodiment, the device value of magenta (M) in the four-color profile is distributed to calculate the device value of fluorescent magenta as a fluorescent coloring material to generate a five-color profile, but the present invention is not limited to this. For example, the device value of cyan (C) or yellow (Y) in the four-color profile may be distributed to calculate the device value of the fluorescent coloring material to generate a five-color profile.

[0081] [Second embodiment] The image forming apparatus according to the second embodiment will be described, focusing on the differences from the image forming apparatus 10 according to the first embodiment. In the first embodiment, an operation using a fixed distribution ratio to generate a five-color profile from a four-color profile was described. In this embodiment, an operation of changing the distribution ratio according to the Lab value when generating a five-color profile will be described. Note that the hardware configuration and functional block configuration of the image forming apparatus according to this embodiment are similar to the configurations described in the first embodiment.

[0082] 12 is a graph showing the relationship between saturation and the distribution ratio. The relationship between saturation and the distribution ratio will be described with reference to FIG.

[0083] As shown in FIG. 12, the distribution rate α is determined according to the saturation S, and when distributing the device value of magenta (M) to the device value of fluorescent magenta (NM), the distribution rate α determined from the saturation S of the lattice point (Lab value) is used. That is, the color conversion profile generation unit 303 calculates the saturation S from the Lab value (Lab lattice point) described in the BtoA table of the four-color profile as the printer profile, and determines the distribution rate α according to the saturation S. For example, as shown in FIG. 12, the color conversion profile generation unit 303 may determine a function that prescribes the relationship between the saturation S and the distribution rate α in advance, and determine the distribution rate α from the saturation S. This determination of the distribution rate α by the color conversion profile generation unit 303 may be executed in step S14 of FIG. 9 described above. Note that other processes in the generation process of the five-color profile and the printing process of the image forming device 10 are the same as those described above in the first embodiment.

[0084] The above-described operation also makes it possible to obtain the same effects as those of the first embodiment.

[0085] [Third embodiment] The image forming apparatus according to the third embodiment will be described, focusing on the differences from the image forming apparatus 10 according to the first embodiment. In the first embodiment, the operation of distributing the device values ​​of the process colors directly to the device values ​​of the fluorescent colors was described. In this case, the color values ​​defined in the Lab color space may not match the color values ​​of the target color. In this embodiment, the operation of calculating the device values ​​of other process colors based on at least the device values ​​of the fluorescent colors and the color values ​​of the target color to obtain color values ​​close to the target color will be described. Note that the hardware configuration of the image forming apparatus according to this embodiment is the same as the configuration described in the first embodiment.

[0086] Designers specify colors by referring to patch colors (target colors) in a color sample book. Examples of target colors include colors specified in color sample books or color chips specified by DIC Color Guide (registered trademark) or PANTONE (registered trademark), and in the case of the DIC Color Guide, for example, the color name is specified, such as "DIC001". In these color sample books, color sample samples consisting of multiple patches and corresponding Lab values ​​are provided, and the described Lab values ​​become the color values ​​of the target colors. Hereinafter, data consisting of pairs of color names and color values ​​in the color sample book will be referred to as color sample data. Note that the results of color measurement by the colorimeter 233 may be used as target colors in order to match the color measurement conditions when creating color reproduction characteristics in the color reproduction characteristics creation unit 313 described later.

[0087] Currently, there are no official regulations for numerically managing fluorescent colors. However, for example, if a user is to view a printed matter under fluorescent lighting that does not contain ultraviolet light, it is possible to express the color in an approximate color using the Lab color space standardized by the International Commission on Illumination (CIE: Commission Internationale de I'Eclairage) and adopted in Japan's JIS (Japanese Industrial Standards). By using these, it is possible to create a profile in which fluorescent colors are mixed with process colors, or to create a spot color dictionary. In this embodiment, an operation for creating a spot color dictionary for reproducing a target color in a color sample book will be described.

[0088] (Configuration and operation of functional blocks of a controller of an image forming apparatus) Fig. 13 is a diagram showing an example of the configuration of the functional blocks of a controller of an image forming apparatus according to the third embodiment. Fig. 14 is a diagram showing an example of a spot color dictionary. The configuration and operation of the functional blocks of a controller 200a of an image forming apparatus according to this embodiment will be described with reference to Figs. 13 and 14.

[0089] As shown in FIG. 13, the controller 200a has a memory unit 301, a data input / output unit 302, a spot color dictionary generation unit 303a (second generation unit), an image data acquisition unit 304 (first acquisition unit), a color conversion unit 305a, an image output unit 306, a chart image generation unit 311, a colorimetric value acquisition unit 312 (second acquisition unit), and a color reproduction characteristic creation unit 313 (creation unit).

[0090] The storage unit 301 is a functional unit that stores a four-color profile and color sample data (color sample information), and stores a spot color dictionary generated by a spot color dictionary generating unit 303a (described later). The storage unit 301 is realized by the auxiliary storage device 208 shown in FIG.

[0091] The data input / output unit 302 is a functional unit that reads data from the storage unit 301 and writes data to the storage unit 301. The data input / output unit 302 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0092] The spot color dictionary generating unit 303a is a functional unit that receives the four-color profile and color sample data from the storage unit 301 via the data input / output unit 302, distributes the device value of magenta (M) (an example of a process color of the same color system that is a special color) in the target color described in the color sample data, and calculates device values ​​of magenta (M) and fluorescent magenta (NM) (an example of a special color, an example of a fluorescent color).The spot color dictionary generating unit 303a then calculates device values ​​that reproduce the Lab values ​​of the target color using color reproduction characteristics that associate the device values ​​of the printer (plotter 231) and color values ​​(colorimetric values ​​of the colorimeter 233) received from the color reproduction characteristic creating unit 313 with each other, and the calculated device value of fluorescent magenta (NM), and generates a spot color dictionary (dictionary).

[0093] An example of the spot color dictionary (an example of four colors) is shown in Fig. 14. As shown in Fig. 14, the spot color dictionary associates color names (Colorname) as spot colors (special colors) with device values.

[0094] The spot color dictionary generating unit 303a stores the generated spot color dictionary in the storage unit 301 via the data input / output unit 302. The spot color dictionary generating unit 303a is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0095] The image data acquisition unit 304 is a functional unit that acquires, for example, PDF (Portable Document Format) image data (an example of first image data) in which spot color information is written from the PC 20 or the like via the network N. The image data acquisition unit 304 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0096] The color conversion unit 305a is a functional unit that acquires PDF image data in which spot color information is written from the image data acquisition unit 304, receives a spot color dictionary from the storage unit 301 via the data input / output unit 302, and converts all spot colors used in the PDF image data into CMYK+NM values ​​using the spot color dictionary, thereby performing color conversion into 5-plate CMYK+NM image data (an example of second image data) that is dependent on the printer (plotter 231). The color conversion unit 305a is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0097] The image output unit 306 is a functional unit that outputs the five-plate CMYK+NM image data color-converted by the color conversion unit 305a to a printer (plotter 231) and causes the printer to execute printing. The image output unit 306 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0098] The chart image generating unit 311 is a functional unit that holds chart data for obtaining color reproduction characteristics of the printer (plotter 231) and generates the chart data as image data in PDF format (hereinafter referred to as chart image data). Here, the chart data is data in which C, M, Y, K, and NM are each combined for a predetermined gradation value. For example, when the gradation value for each color is 20[%], the chart data is 6 5 The data includes 7776 patches. The chart image generating unit 311 sends the generated chart image data to the color reproduction characteristic creating unit 313 and the image output unit 306. The chart image generating unit 311 is realized by, for example, a program executed by the CPU 201 shown in FIG.

[0099] The colorimetric value acquisition unit 312 is a functional unit that acquires colorimetric values ​​(Lab values) measured by the colorimeter 233. The colorimetric value acquisition unit 312 acquires colorimetric values ​​(Lab values) of a device-independent color space (Lab color space) for patches combining C, M, Y, K, and NM included in the chart image data for each gradation value, by performing colorimetry on a recording medium of the chart image data printed out from the plotter 231 by the image output unit 306 using the colorimeter 233. The colorimeter 233 may perform colorimetry in response to an operation of a user sliding the colorimeter 233 on the recording medium of the chart image data, or may perform colorimetry in response to detection of the output of the chart image data within the printer (plotter 231). The colorimetric value acquisition unit 312 is realized, for example, by a program executed by the CPU 201 shown in FIG. 2.

[0100] The color reproduction characteristic creating unit 313 is a functional unit that creates color reproduction characteristics that associate the CMYK+NM values ​​of the CMYK+NM chart image data received from the chart image generating unit 311 with the colorimetric values ​​(Lab values) for the recording medium of the chart image data printed out from the plotter 231 and acquired by the colorimetric value acquiring unit 312. The color reproduction characteristic creating unit 313 sends the created color reproduction characteristics to the spot color dictionary generating unit 303a. The color reproduction characteristic creating unit 313 is realized by, for example, a program executed by the CPU 201 shown in FIG. 2.

[0101] At least a part of the functional units of the controller 200a illustrated in FIG. 13 that are implemented by software (programs) may be implemented by a hardware circuit such as an FPGA or an ASIC.

[0102] Moreover, each functional unit of the controller 200a shown in Fig. 13 is a conceptual representation of a function, and is not limited to such a configuration. For example, a plurality of functional units illustrated as independent functional units in the controller 200a shown in Fig. 13 may be configured as one functional unit. On the other hand, the function of one functional unit in the controller 200a shown in Fig. 13 may be divided into a plurality of functional units and configured as a plurality of functional units.

[0103] (Spot color dictionary creation process) 15 is a flowchart showing an example of the flow of a spot color dictionary creation process of the image forming apparatus according to the third embodiment. The flow of the spot color dictionary creation process of the image forming apparatus according to the present embodiment will be described with reference to FIG.

[0104] <Step S31> First, the spot color dictionary generating unit 303a acquires the four-color profile and color sample data from the storage unit 301 via the data input / output unit 302. Then, the process proceeds to step S32.

[0105] <Step S32> The spot color dictionary generating unit 303a obtains a BtoA table (see, for example, FIG. 5) from the obtained four-color profile, and then the process proceeds to step S33.

[0106] <Step S33> The spot color dictionary generating unit 303a obtains the Lab value of one target color from the obtained color sample data, and then proceeds to step S34.

[0107] <Step S34> The spot color dictionary generating unit 303a obtains the device value of magenta (M) corresponding to the Lab value of the target color obtained from the color sample data in the obtained four-color profile. The spot color dictionary generating unit 303a then distributes the obtained device value of magenta (M) in the same manner as the color conversion profile generating unit 303 in the first or second embodiment to calculate the device values ​​of magenta (M) and fluorescent magenta (NM). Then, the process proceeds to step S35.

[0108] <Step S35> The spot color dictionary generating unit 303a receives the color reproduction characteristics from the color reproduction characteristic creating unit 313, fixes the calculated device value of fluorescent magenta (NM), and calculates device values ​​of C, M, Y, and K that reproduce the Lab value of the target color using the color reproduction characteristics. Then, the process proceeds to step S36.

[0109] <Step S36> The spot color dictionary generating unit 303a writes information associating the target color with the calculated CMYK+NM value into the spot color dictionary, and then the process proceeds to step S37.

[0110] <Step S37> If the processes in steps S33 to S36 have been completed for all target colors in the color sample data (step S37: Yes), the process proceeds to step S38, and if not (step S37: No), the process returns to step S33.

[0111] <Step S38> The spot color dictionary generating unit 303a generates a spot color dictionary composed of information associating all the target colors with the calculated CMYK+NM values, and stores (preserves) the spot color dictionary in the storage unit 301 via the data input / output unit 302. Then, the spot color dictionary creation process ends.

[0112] (Printing process of image forming device) 16 is a flowchart showing an example of the flow of print processing in the image forming apparatus according to the third embodiment. The flow of print processing in the image forming apparatus according to the present embodiment will be described with reference to FIG.

[0113] <Step S41> First, when a user performs an operation to print image data via the operation display unit 210, the image data acquisition unit 304 acquires the PDF image data in which the spot color information is written via the network N. Then, the process proceeds to step S42.

[0114] <Step S42> The color conversion unit 305a acquires the PDF image data acquired by the image data acquisition unit 304, and acquires the spot color dictionary from the storage unit 301 via the data input / output unit 302. Then, the process proceeds to step S43.

[0115] <Step S43> The color conversion unit 305a uses the acquired spot color dictionary to convert the spot colors used (described) in the PDF image data into CMYK+NM device values ​​(CMYK+NM values), and then proceeds to step S44.

[0116] <Step S44> If the conversion process by the color conversion unit 305a has been completed for all spot colors in the PDF image data (step S44: Yes), the process proceeds to step S45, and if not (step S44: No), the process returns to step S43.

[0117] <Step S45> The color conversion unit 305a converts all spot colors used in the PDF image data into CMYK+NM values ​​in steps S43 and S44, thereby converting the colors into CMYK+NM image data of five plates that depend on the printer (plotter 231), and then the process proceeds to step S46.

[0118] <Step S46> The color conversion unit 305a sends the generated CMYK+NM image data of five plates to the image output unit 306. Then, the image output unit 306 outputs the CMYK+NM image data of five plates to a printer (plotter 231) and causes the printer to execute printing.

[0119] As described above, in the image forming apparatus according to the present embodiment, the spot color dictionary generating unit 303a obtains the device value of fluorescent magenta (NM) corresponding to the target color from the four-color profile and color sample data, calculates the device values ​​of C, M, Y, and K using the color reproduction characteristics of the printer, and generates a spot color dictionary. Then, the color converting unit 305a converts the spot color of the PDF image data into a five-plate CMYK+NM value using the spot color dictionary, thereby converting the color into five-plate CMYK+NM image data. This allows an algorithm for color conversion to be constructed, making it easier to create image data when using a fluorescent coloring material. Furthermore, the generation of the spot color dictionary makes it possible to reproduce the target color in the color sample book.

[0120] In this embodiment, the operation of calculating CMYK device values ​​from the device value of fluorescent magenta (NM) and the target color using color reproduction characteristics has been described, but this is not limited to this. If the method of adding black (K) is set in advance taking into account graininess, it is also possible to calculate CMY device values ​​from the device values ​​of fluorescent magenta (NM) and black (K) and the target color.

[0121] [Fourth embodiment] The image forming apparatus according to the fourth embodiment will be described, focusing on the differences from the image forming apparatus 10 according to the first embodiment. In the first embodiment, an operation was described in which a five-color profile is easily generated from a four-color profile using a fixed distribution ratio, and four-plate image data is converted into five-plate image data in which fluorescent magenta is distributed. In this embodiment, an operation is described in which a profile is used to convert the ratio of the device values ​​of magenta and fluorescent magenta from the five-plate image data in order to maintain gray expression. Note that the hardware configuration of the image forming apparatus according to this embodiment is similar to the configuration described in the first embodiment.

[0122] As mentioned above, substituting fluorescent colorants of the same color type instead of process colors has the advantage that the color does not become dull, but the replaced fluorescent colorants mix with gray, changing the mixing ratio of the process colors that express gray, resulting in deviation from the gray you want to express, and it is known that this has a noticeable effect on the appearance, especially in areas with low saturation. Since gray is expressed by mixing process colors, it requires numerically accurate reproduction. Therefore, it is preferable not to change the mixing ratio of C (cyan), M (magenta), and Y (yellow) (if the ratio has already been adjusted including fluorescent colorants, the ratio including fluorescent colorants). Here, gray and the expression of gray do not mean gray in the sense of gray, but a color in a color area with low saturation and a representation of that color. For example, if fluorescent magenta colorants are newly used in 4-plate image data, the ratio of magenta and fluorescent magenta can be maintained by not using fluorescent colorants when the output is gray, and increasing the mixing ratio of fluorescent colorants when the output is other than gray.

[0123] In summary, in order to prevent the balance of gray expression in a five-color profile from being lost, the ratio between the device value of magenta and the device value of fluorescent magenta is changed based on saturation, and the device values ​​of magenta and fluorescent magenta are calculated. An example of the operation of the controller of the image forming apparatus according to this embodiment for color converting five-plate CMYK+NM image data to five-plate CM'YK+NM' image data having different device values ​​for M and NM will be described. Note that this embodiment is not limited to color conversion from five-plate image data to five-plate image data, and can also be applied to color conversion from four-plate image data to five-plate image data.

[0124] Although details will be described later, in this embodiment, changing the ratio between the device values ​​of magenta and fluorescent magenta based on saturation is performed, for example, as follows.

[0125] The device values ​​before the change are as follows: Magenta device value before change: m Fluorescent magenta device value before change: n (0≦m≦100,0≦ n ≦100)

[0126] The changed device value is calculated as follows: Magenta device value after change: mm×γ After change: Fluorescent magenta device value: n+m×γ (0≦γ≦1)

[0127] Here, γ is a value based on saturation, and when the saturation is low, the value is 0, and when the saturation is high, the value is large.

[0128] The changed device value may be calculated as follows. Magenta device value after change: mm×γ After change: Fluorescent magenta device value: n+m×γ+β (0≦γ≦1, β: any value)

[0129] Below, an example will be described in which the changed magenta device value is calculated as mm×γ, and the changed fluorescent magenta device value is calculated as n+m×γ.

[0130] (Configuration and operation of functional blocks of a controller of an image forming apparatus) FIG. 18 is a diagram showing an example of the configuration of the functional blocks of the color conversion unit of the controller of the image forming apparatus according to the fourth embodiment. FIG. 19 is a diagram showing an example of the BtoA table of the pre-change five-color profile. FIG. 20 is a diagram showing an example of the BtoA table of the post-change five-color profile. FIG. 21 is a diagram showing an example of the AtoB table of the pre-change five-color profile. FIG. 22 is a diagram showing an example of the AtoB table of the post-change five-color profile. FIG. 23 is a graph showing an example of the relationship between saturation and distribution rate. FIG. 24 is a graph showing another example of the relationship between saturation and distribution rate. The configuration and operation of the controller of the image forming apparatus according to the present embodiment will be described with reference to FIGS. 18 to 24.

[0131] The controller 200 of the image forming apparatus 10 according to this embodiment has a data input / output unit 302b, an image data acquisition unit 304b and a color conversion unit 305b instead of the data input / output unit 302, the image data acquisition unit 304 and the color conversion unit 305 of the configuration shown in FIG. 3 above.

[0132] The storage unit 301 is a functional unit that stores a five-color ICC profile before the ratio of the device values ​​of magenta and fluorescent magenta is changed (hereinafter referred to as a pre-change five-color profile), and a five-color ICC profile after the ratio of the device values ​​of magenta and fluorescent magenta is changed (hereinafter referred to as a post-change five-color profile) generated by the color conversion profile generation unit 303. The storage unit 301 is realized by the auxiliary storage device 208 shown in FIG.

[0133] The data input / output unit 302b is a functional unit that reads data from the storage unit 301 and writes data to the storage unit 301. The data input / output unit 302b is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0134] The color conversion profile generation unit 303 (third generation unit) is a functional unit that receives the pre-change five-color profile from the memory unit 301 via the data input / output unit 302b, and calculates the device values ​​of magenta (M) (an example of a fluorescent homochromatic process color) and fluorescent magenta (NM) (an example of a fluorescent color) by changing the ratio of the device values ​​of magenta (M) and fluorescent magenta (NM), thereby generating a post-change five-color profile.

[0135] FIG. 19 shows the BtoA table of the 5-color profile before the change. In this embodiment, in order to generate the 5-color profile after the change, the color conversion profile generation unit 303 changes the ratio of the device values of magenta (M) and fluorescent magenta (NM) of the 5-color profile before the change acquired from the storage unit 301 via the data input / output unit 302b, and assigns a distribution ratio when calculating the device values of magenta (M) and fluorescent magenta (NM). That is, when the CMYK+NM values corresponding to the Lab values (Lab grid points) described in the BtoA table of the 5-color profile before the change as the printer profile are C = c (0 ≦ c ≦ 100), Y = y (0 ≦ y ≦ 100), and K = k (0 ≦ k ≦ 100), respectively, the ratio is changed only for the device values of magenta (M) and fluorescent magenta (NM), and using the distribution ratio γ based on the chroma, C = c, M = m - m×γ (m - n×γ > 0), Y = y, K = k, NM = n + m×γ, the device values of magenta (M) and fluorescent magenta (NM) are calculated. Here, the distribution ratio γ has a value of 0 ≦ γ ≦ 1 and is a ratio determined based on the chroma X directly obtained from the Lab values (specifically, a and b among the Lab values). For example, the distribution ratio γ may be determined such that it becomes smaller as the chroma becomes smaller (larger as the chroma becomes larger) at least in a predetermined range of the chroma. For example, when the chroma X obtained from a and b among the Lab values is 17 or less (that is, when the chroma is low), γ = 0 (that is, no distribution), and when the chroma X is 34 or more (that is, when the chroma is high), γ ≒ 1, and when 17 < X < 34, the distribution ratio γ may take values as shown in FIG. 23 as an example. Note that the values of the distribution ratio γ in FIG. 23 are just an example, and it may take values as shown in FIG. 24. That is, when it is less than a predetermined chroma X (for example, 17), the distribution ratio γ may be set to 0, and when it is greater than the predetermined chroma X, the distribution ratio γ may be set to 1. Then, the color conversion profile generation unit 303 changes the ratio for the device values of magenta (M) and fluorescent magenta (NM) for all the Lab values (Lab grid points) in the BtoA table of the 5-color profile before the change, and calculates the device values of magenta (M) and fluorescent magenta (NM).Then, the color conversion profile generation unit 303 generates a BtoA table of the changed five-color profile shown in Fig. 20 by setting the CMYK+NM value corresponding to each Lab value (Lab lattice point). Note that m in Figs. max , n max For example, "100".

[0136] Similarly, the color conversion profile generation unit 303 calculates device values ​​of magenta (M) and fluorescent magenta (NM) for each CMYK+NM value (CMYK+NM grid point) described in the AtoB table of the pre-change five-color profile serving as the source profile shown in Fig. 21, in the same manner as the BtoA table described above. Then, the color conversion profile generation unit 303 generates the AtoB table of the post-change five-color profile shown in Fig. 22.

[0137] Here, the color conversion profile generating unit 303 rewrites only the device values ​​in both the BtoA table and the AtoB table, and does not rewrite the Lab values ​​that constitute the PCS. The color conversion profile generating unit 303 then rewrites the necessary tags.

[0138] The color transformation profile generation unit 303 stores the generated five-color profile in the storage unit 301 via the data input / output unit 302b. The color transformation profile generation unit 303 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0139] The image data acquisition unit 304b is a functional unit that acquires CMYK+NM image data (an example of first image data) from, for example, the PC 20 via the network N. The image data acquisition unit 304b sends the acquired CMYK+NM image data to the color conversion unit 305b. The image data acquisition unit 304b is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0140] The color conversion unit 305b is a functional unit that acquires CMYK+NM image data from the image data acquisition unit 304b, acquires a five-color profile from the storage unit 301 via the data input / output unit 302b, and uses the acquired five-color profile to color-convert the acquired five-color CMYK+NM image data into five-color CM'YK+NM' image data (an example of second image data) that depends on the printer (plotter 231). As the CMYK+NM image data and CM'YK+NM' image data, for example, color data created by changing the device values ​​of C, M, Y, K, and NM within the range of 0 to 100 may be used.

[0141] As shown in FIG. 18, the color conversion unit 305b includes a source profile conversion unit 3051b and a printer profile conversion unit 3052b.

[0142] The source profile conversion unit 3051b is a functional unit that acquires a pre-change five-color profile (AtoB table) from the storage unit 301 via the data input / output unit 302b, and converts the CMYK+NM values ​​of each pixel constituting the five-plate CMYK+NM image data acquired from the image data acquisition unit 304b into Lab values ​​using the pre-change five-color profile. The source profile conversion unit 3051b sends the converted Lab values ​​to the printer profile conversion unit 3052b.

[0143] The printer profile conversion unit 3052b is a functional unit that acquires a changed five-color profile (BtoA table) from the storage unit 301 via the data input / output unit 302b, and converts the Lab values ​​received from the source profile conversion unit 3051b into five-color CM'YK+NM' image data consisting of CM'YK+NM' values ​​using the changed five-color profile. The printer profile conversion unit 3052b sends the converted five-color CM'YK+NM' image data to the image output unit 306.

[0144] The color conversion unit 305b is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0145] The image output unit 306 is a functional unit that outputs the CM'YK+NM' image data color-converted by the color conversion unit 305b to a printer (plotter 231) and causes the printer to execute printing. The image output unit 306 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0146] At least a part of the functional units of the controller 200 according to this embodiment that are implemented by software (programs) may be implemented by a hardware circuit such as an FPGA or an ASIC.

[0147] Moreover, each functional unit of the controller 200 according to this embodiment is a conceptual representation of a function, and is not limited to such a configuration. For example, a plurality of functional units shown as independent functional units in the controller 200 may be configured as one functional unit. On the other hand, the function of one functional unit in the controller 200 may be divided into a plurality of units and configured as a plurality of functional units.

[0148] (5-color profile generation process) Fig. 25 is a flowchart showing an example of the flow of a process for generating a changed five-color profile of the image forming apparatus according to the fourth embodiment. The flow of the process for generating a changed five-color profile of the image forming apparatus 10 according to the present embodiment will be described with reference to Fig. 25.

[0149] <Step S11a> First, the color transformation profile generation unit 303 acquires the pre-change five-color profile (first profile) from the storage unit 301 via the data input / output unit 302b. Then, the process proceeds to step S12a.

[0150] <Step S12a> The color transformation profile generation unit 303 acquires a BtoA table (see, for example, FIG. 19) from the acquired pre-conversion five-color profile, and then proceeds to step S13a.

[0151] <Step S13a> The color conversion profile generation unit 303 extracts the CMYK+NM values ​​as grid point information from the BtoA table of the acquired pre-conversion five-color profile, and then proceeds to step S14a.

[0152] <Step S14a> The color conversion profile generation unit 303 changes the ratio of the device values ​​of magenta (M) and fluorescent magenta (NM) among the extracted CMYK+NM values ​​by the above-mentioned method, and calculates the device values ​​of magenta (M) and fluorescent magenta (NM). Then, the process proceeds to step S15a.

[0153] <Step S15a> The color conversion profile generation unit 303, for example, rewrites the CMYK+NM values ​​of the BtoA table of the acquired pre-change five-color profile with the CM'YK+NM' values ​​including the calculated device values ​​of magenta (M) and fluorescent magenta (NM). Then, the process proceeds to step S16a.

[0154] <Step S16a> If the processing of steps S13a to S15a has been completed for all CMYK+NM values ​​(lattice point information) in the BtoA table of the pre-change five-color profile acquired by the color conversion profile generation unit 303 (step S16a: Yes), proceed to step S17a, and if not completed (step S16a: No), return to step S13a. If the processing of steps S13a to S15a has been completed for all CMYK+NM values ​​(lattice point information) in the BtoA table of the pre-change five-color profile acquired by the color conversion profile generation unit 303, the BtoA table of the post-change five-color profile has been generated.

[0155] <Step S17a> If the processes of steps S13a to S16a have already been performed on the AtoB table of the pre-change five-color profile (step S17a: Yes), the process proceeds to step S19a, and if not (step S17a: No), the process proceeds to step S18a.

[0156] <Step S18a> The color transformation profile generation unit 303 acquires an AtoB table (see, for example, FIG. 21) from the acquired pre-conversion five-color profile. Then, the process returns to step S13a.

[0157] <Step S19a> The color transformation profile generating unit 303 changes tag information such as the date of the changed five-color profile as necessary. When the color transformation profile generating unit 303 generates the BtoA table and the AtoB table of the changed five-color profile (second profile) for the BtoA table and the AtoB table of the pre-change five-color profile, the generation process of the changed five-color profile ends.

[0158] (Color conversion processing in printing processing of image forming device) Fig. 26 is a flow chart showing an example of the flow of color conversion processing in the print processing of the image forming apparatus according to the fourth embodiment. The color conversion processing shown in Fig. 26 corresponds to the processing of step S22 shown in Fig. 10 of the first embodiment described above (the color conversion processing shown in Fig. 11). The flow of color conversion processing in the print processing of the image forming apparatus 10 according to this embodiment will be described with reference to Fig. 26. It is assumed that the five-color profile (BtoA table) shown in Fig. 25 described above has been generated in advance and stored in the storage unit 301.

[0159] <Step S221a> The source profile conversion unit 3051b of the color conversion unit 305b acquires the five-plate CMYK+NM image data acquired by the image data acquisition unit 304b. Then, the process proceeds to step S222a.

[0160] <Step S222a> The source profile conversion unit 3051b acquires the pre-change five-color profile via the data input / output unit 302b from the storage unit 301. The printer profile conversion unit 3052b of the color conversion unit 305b acquires the post-change five-color profile via the data input / output unit 302b from the storage unit 301. Then, the process proceeds to step S223a.

[0161] <Step S223a> Next, the source profile conversion unit 3051b converts the CMYK+NM values ​​of the pixels constituting the acquired five-color image data of CMYK+NM to Lab values ​​using the acquired pre-conversion five-color profile (AtoB table). Then, the source profile conversion unit 3051b sends the converted Lab values ​​to the printer profile conversion unit 3052b. Then, the process proceeds to step S224a.

[0162] <Step S224a> The printer profile conversion unit 3052b converts the Lab values ​​received from the source profile conversion unit 3051b to CM'YK+NM' values ​​using the acquired changed five-color profile (BtoA table), and replaces the target CMYK+NM values ​​with CM'YK+NM' values ​​in the five-plate CMYK+MN image data. Then, the process proceeds to step S225a.

[0163] <Step S225a> If conversion and replacement to CM'YK+NM' values ​​has been completed for all pixels of the five-plate CMYK+NM image data before conversion (step S225a: Yes), proceed to step S226a; if processing has not been completed for all pixels (step S225a: No), return to step S223a.

[0164] <Step S226a> The printer profile conversion unit 3052b generates image data in which all CMYK+NM values ​​of pixels constituting the pre-conversion five-plate CMYK+NM image data have been replaced with CM'YK+NM' values ​​in which the ratio of magenta (M) and fluorescent magenta (NM) device values ​​has been changed, as the converted five-plate CM'YK+NM' image data. The CM'YK+NM' values ​​constituting the converted five-plate CM'YK+NM' image data become device values ​​dependent on the printer (plotter 231). Then, the process proceeds to step S227a.

[0165] <Step S227a> The printer profile conversion unit 3052b sends the generated converted 5-plate CM'YK+NM' image data to the image output unit 306. Then, the color conversion process ends.

[0166] As described above, in the image forming apparatus 10 according to this embodiment, the color conversion profile generation unit 303 generates a ratio-changed five-color profile from the pre-change five-color profile, the color conversion unit 305b converts the five-plate CMYK+NM image data to Lab values ​​using the pre-change five-color profile, and the Lab values ​​are converted to CM'YK+NM' values ​​using the post-change five-color profile, thereby converting the color into five-plate CM'YK+NM' image data with a changed ratio of the device values ​​of magenta (M) and fluorescent magenta (NM). This creates an algorithm for color conversion, suppresses the loss of balance in gray when using fluorescent color materials, and enables the creation of image data with vivid color, which is an advantage of fluorescent color materials.

[0167] In the above embodiment, the ratio of the device values ​​of magenta (M) and fluorescent magenta (NM) in the pre-change five-color profile is changed to calculate the device value of fluorescent magenta as a fluorescent colorant to generate the post-change five-color profile, but this is not limiting. For example, the ratio of the device values ​​of cyan (C) and fluorescent cyan (NC), or yellow and fluorescent yellow (NY) in the pre-change five-color profile may be changed to calculate each device value to generate the post-change five-color profile.

[0168] Furthermore, as described above, even when inputting 4-plate image data, by using a 4-color profile (AtoB table) instead of the pre-change 5-color profile (AtoB table), it is possible to convert the 4-plate image data to 5-plate image data while suppressing the loss of gray balance.

[0169] [Fifth embodiment] The image forming apparatus according to the fifth embodiment will be described, focusing on the differences from the image forming apparatus 10 according to the fourth embodiment. In the fourth embodiment, the operation of converting the ratio of the device values ​​of magenta and fluorescent magenta using a profile in order to maintain gray expression from five-plate image data will be described. In this embodiment, the operation of converting the ratio of the device values ​​of magenta and fluorescent magenta without using a profile in order to maintain gray expression from five-plate image data will be described. Note that the hardware configuration of the image forming apparatus according to this embodiment is similar to the configuration described in the first embodiment.

[0170] In summary, in order to prevent the balance of gray expression in a five-color profile from being lost, the device values ​​of magenta and fluorescent magenta are calculated by changing the ratio between the device values ​​of magenta and fluorescent magenta based on saturation without using a profile. An example of the operation of the controller of the image forming apparatus according to this embodiment for color converting five-plate CMYK+NM image data to five-plate CM'YK+NM' image data having different device values ​​for M and NM will be described. Note that this embodiment is not limited to color conversion from five-plate image data to five-plate image data, and can also be applied to color conversion from four-plate image data to five-plate image data.

[0171] (Configuration and operation of functional blocks of a controller of an image forming apparatus) Fig. 27 is a diagram showing an example of the functional block configuration of a color conversion unit of a controller of an image forming apparatus according to the fifth embodiment. The configuration and operation of the controller of the image forming apparatus according to the present embodiment will be described with reference to Fig. 27.

[0172] The controller 200 of the image forming apparatus 10 according to this embodiment does not have the data input / output unit 302 and the color conversion profile generation unit 303 of the configuration shown in FIG. 3 above, and instead of the image data acquisition unit 304 and the color conversion unit 305, it has an image data acquisition unit 304c and a color conversion unit 305c, respectively.

[0173] The storage unit 301 is a functional unit that stores information on a function of saturation X and distribution rate γ as shown in, for example, Fig. 23 or 24. The storage unit 301 is realized by the auxiliary storage device 208 shown in Fig. 2.

[0174] The image data acquisition unit 304c is a functional unit that acquires CMYK+NM image data (an example of first image data) from, for example, the PC 20 via the network N. The image data acquisition unit 304c sends the acquired CMYK+NM image data to the color conversion unit 305c. The image data acquisition unit 304c is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0175] The color conversion unit 305c is a functional unit that acquires CMYK+NM image data from the image data acquisition unit 304c, and converts the acquired five-color CMYK+NM image data into five-color CM'YK+NM' image data (an example of second image data) that depends on the printer (plotter 231). The CMYK+NM image data and CM'YK+NM' image data use color data created by changing the device values ​​of C, M, Y, K, and NM in the range of 0 to 100.

[0176] As shown in FIG. 27, the color conversion unit 305c includes a saturation derivation unit 3051c and a distribution calculation unit 3052c.

[0177] The saturation derivation unit 3051c is a functional unit that derives saturation X from the CMYK+NM values ​​of each pixel constituting the five-plate CMYK+NM image data acquired from the image data acquisition unit 304c. FIG. 28 shows a state where a point with a device value of 0% (paper white) and each point of C, M, Y, and NM with a device value of 100% (solid) are plotted on a hue plane. C, M, and Y have an angle difference of about 120 degrees as a hue angle, and NM has a hue angle almost equal to M. Therefore, since saturation X can be calculated by finding the distance from the achromatic axis, it can be calculated from the absolute value of c+(m+n)·cos2π / 3+y·cos4π / 3 using, for example, the device value c of C, the device value m of M, the device value y of Y, and the device value n of NM. That is, saturation X is calculated from the following formula (1).

[0178] X=|c+(m+n)·cos2π / 3+y·cos4π / 3| ···(1)

[0179] The reason why the saturation X is calculated by the above formula (1) is that when c=m=y, it can be approximately gray, and similarly, if c=(m+n)=y and it is gray, it is necessary to change the ratio based on the saturation and maintain the ratio of fluorescent magenta (NM). Therefore, the saturation derivation unit 3051c derives the saturation X from the CMYK+NM values ​​of each pixel constituting the five-plate CMYK+NM image data acquired from the image data acquisition unit 304c, for example, by calculating the above formula (1). The saturation derivation unit 3051c then sends the derived saturation X and the five-plate CMYK+NM image data to the distribution calculation unit 3052c.

[0180] The distribution calculation unit 3052c is a functional unit that calculates a distribution rate γ from the saturation X derived by the saturation derivation unit 3051c. Specifically, the distribution calculation unit 3052c reads out information on a function of saturation X and distribution rate γ, for example, as shown in FIG. 23 or FIG. 24, stored in the storage unit 301, and calculates a distribution rate γ based on the function from the saturation X acquired from the saturation derivation unit 3051c. Then, the distribution calculation unit 3052c changes the ratio only for the device values ​​of magenta (M) and fluorescent magenta (NM) among the acquired five-plate CMYK+NM image data, and converts it into five-plate CM'YK+NM' image data consisting of CM'YK+NM' values ​​by calculating the device values ​​of magenta (M) and fluorescent magenta (NM) using the calculated distribution rate γ as C=c, M=mm×γ, Y=y, K=k, and NM=n+m×γ. The distribution calculation unit 3052 c sends the converted CM′YK+NM′ image data of five plates to the image output unit 306 .

[0181] The color conversion unit 305c is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0182] The image output unit 306 is a functional unit that outputs the CM'YK+NM' image data color-converted by the color conversion unit 305c to a printer (plotter 231) and causes the printer to execute printing. The image output unit 306 is realized, for example, by a program executed by the CPU 201 shown in FIG.

[0183] At least a part of the functional units of the controller 200 according to this embodiment that are implemented by software (programs) may be implemented by a hardware circuit such as an FPGA or an ASIC.

[0184] Moreover, each functional unit of the controller 200 according to the present embodiment is shown conceptually, and is not limited to such a configuration. For example, a plurality of functional units shown as independent functional units in the controller 200 may be configured as one functional unit. On the other hand, the function of one functional unit in the controller 200 may be divided into a plurality of units and configured as a plurality of functional units. For example, the saturation derivation unit 3051c and the distribution calculation unit 3052c may be configured as one unified image processing unit.

[0185] (Color conversion processing in printing processing of image forming device) Fig. 29 is a flowchart showing an example of the flow of color conversion processing in the print processing of the image forming apparatus according to the fifth embodiment. The color conversion processing shown in Fig. 29 corresponds to the processing of step S22 shown in Fig. 10 of the first embodiment (the color conversion processing shown in Fig. 11). The flow of color conversion processing in the print processing of the image forming apparatus 10 according to this embodiment will be described with reference to Fig. 29.

[0186] <Step S221b> The saturation deriving unit 3051c of the color conversion unit 305c acquires the five-plate CMYK+NM image data acquired by the image data acquisition unit 304c. Then, the process proceeds to step S222b.

[0187] <Step S222b> The saturation deriving unit 3051c extracts the device value (CMYK+NM value) of the target pixel from the acquired CMYK+NM image data of five plates. Then, the process proceeds to step S223b.

[0188] <Step S223b> The saturation derivation unit 3051c derives the saturation X from the extracted CMYK+NM value, for example, by calculating the above formula (1). Then, the saturation derivation unit 3051c sends the derived saturation X and the five-plate CMYK+NM image data to the distribution calculation unit 3052c. Note that the saturation derivation unit 3051c needs to send the five-plate CMYK+NM image data to the distribution calculation unit 3052c only once. Then, the process proceeds to step S224b.

[0189] <Step S224b> The distribution calculation unit 3052c calculates the distribution rate γ from the saturation X derived by the saturation derivation unit 3051c. Specifically, the distribution calculation unit 3052c reads out information on a function between the saturation X and the distribution rate γ, for example, as shown in Fig. 23 or 24, stored in the storage unit 301, and calculates the distribution rate γ based on the function from the saturation X acquired from the saturation derivation unit 3051c. Then, the process proceeds to step S225b.

[0190] <Step S225b> The distribution calculation unit 3052c uses the calculated distribution rate γ to calculate the device values ​​of magenta (M) and fluorescent magenta (NM) with C=c, M=mm×γ, Y=y, K=k, and NM=n+m×γ, changes the ratio only for the device values ​​of magenta (M) and fluorescent magenta (NM), converts them to CM'YK+NM' values, and replaces the target CMYK+NM values ​​with CM'YK+NM' values ​​in the 5-plate CMYK+MN image data.Then, the process proceeds to step S226b.

[0191] <Step S226b> If conversion and replacement to CM'YK+NM' values ​​has been completed for all pixels of the five-plate CMYK+NM image data before conversion (step S226b: Yes), proceed to step S227b; if processing has not been completed for all pixels (step S226b: No), return to step S222b.

[0192] <Step S227b> The distribution calculation unit 3052c generates image data in which all CMYK+NM values ​​of pixels constituting the pre-conversion five-plate CMYK+NM image data have been replaced with CM'YK+NM' values ​​in which the ratio of magenta (M) and fluorescent magenta (NM) device values ​​has been changed, as the converted five-plate CM'YK+NM' image data. The CM'YK+NM' values ​​constituting the converted five-plate CM'YK+NM' image data become device values ​​dependent on the printer (plotter 231). Then, the process proceeds to step S228b.

[0193] <Step S228b> The distribution calculation unit 3052c sends the generated converted 5-plate CM'YK+NM' image data to the image output unit 306. Then, the color conversion process ends.

[0194] As described above, in the image forming apparatus 10 according to this embodiment, the chroma X is derived from the CMYK+NM image data of five plates before conversion using the device value, the distribution rate γ is calculated from the chroma X, and the distribution rate γ is used to change the ratio of the device values ​​of magenta (M) and fluorescent magenta (NM), thereby converting the color into CM'YK+NM' image data of five plates. This achieves the same effects as the fourth embodiment described above, and makes it possible to omit the process of converting to Lab values ​​in advance and generating a profile for converting from the Lab values.

[0195] In the above embodiment, the ratio of the device values ​​of magenta (M) and fluorescent magenta (NM) before the change is changed, the device value of fluorescent magenta as a fluorescent colorant is calculated, and the CM'YK+NM' value after the change is obtained, but this is not limited to the above. For example, the ratio of the device values ​​of cyan (C) and fluorescent cyan (NC), or yellow and fluorescent yellow (NY) before the change may be changed, and each device value may be calculated to obtain the CM'YK+NM' value after the change.

[0196] Furthermore, the image data acquired by the image data acquisition unit 304c may be four-plate image data. In this case, for example, the saturation may be calculated assuming that the NM device value is input as 0, and the distribution ratio may be calculated.

[0197] Also, the distribution ratio may be changed not only based on the saturation but also by calculating the lightness from the K value and the saturation of CMY+NM.

[0198] In each of the above-mentioned embodiments, when at least one of the functional units of the controllers 200 and 200a of the image forming apparatus is realized by executing a program, the program is provided by being pre-installed in a ROM or the like. In each of the above-mentioned embodiments, the program executed by the controllers 200 and 200a of the image forming apparatus may be provided by being recorded in a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (Compact Disk-Recordable), or a DVD (Digital Versatile Disc) in an installable or executable format. In each of the above-mentioned embodiments, the program executed by the controllers 200 and 200a of the image forming apparatus may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. In each of the above-mentioned embodiments, the program executed by the controllers 200 and 200a of the image forming apparatus may be provided or distributed via a network such as the Internet. Furthermore, in each of the above-mentioned embodiments, the program executed by the controller 200, 200a of the image forming apparatus has a modular configuration including at least any one of the above-mentioned functional units, and in terms of actual hardware, the CPU 201 reads out and executes the program from the above-mentioned storage device (e.g., the system memory 202 or the auxiliary storage device 208, etc.), so that each of the above-mentioned functional units is loaded and generated on the main storage device. [Explanation of symbols]

[0199] 10 Image forming device 20 PC 200, 200a Controller 201 CPU 202 System Memory (MEM-P) 203 Northbridge (NB) 204a South Bridge (SB) 204b Network I / F 204c USB I / F 204d Centronics I / F 205 AGP 206 ASIC 207 Local Memory (MEM-C) 208 Auxiliary storage 210 Operation display section 220 FCU 231 Plotter 232 Scanner 233 Colorimeter 301 Storage section 302, 302b Data input / output section 303 Color conversion profile generator 303a Spot color dictionary generation unit 304, 304b, 304c Image data acquisition unit 305, 305a to 305c Color conversion unit 306 Image output unit 311 Chart image generator 312 Colorimetric value acquisition unit 313 Color Reproduction Characteristic Creation Section 3051, 3051b Source profile conversion section 3051c Saturation derivation part 3052, 3052b Printer Profile Conversion Unit 3052c Distribution calculation section N Network [Prior art documents] [Patent documents]

[0200]

Patent Document 1

Claims

1. a first acquisition unit that acquires first image data to be subjected to color conversion; a color conversion unit that converts the first image data acquired by the first acquisition unit into second image data in which a dot area ratio of one of the process colors indicated by the first image data is distributed to a dot area ratio of a fluorescent color different from the process color and a dot area ratio of the process color; Equipped with the color conversion unit calculates the dot area ratio of the one color and the dot area ratio of the fluorescent color using a distribution rate that is positively correlated with saturation, the distribution rate being calculated based on the dot area ratio of the process color of the first image data.

2. A first acquisition unit that acquires first image data to be subjected to color conversion; a color conversion unit that converts the first image data acquired by the first acquisition unit into second image data in which a dot area ratio of one of the process colors indicated by the first image data is distributed to a dot area ratio of a fluorescent color different from the process color and a dot area ratio of the process color; Equipped with The color conversion unit is configured to not allocate the dot area rate of the fluorescent color from the dot area rate of the one color when the saturation calculated based on the dot area rate of the process color of the first image data is equal to or lower than a predetermined threshold value.

3. 3. The image processing device according to claim 1, wherein the second image data has a ratio between the dot area percentage of the fluorescent color contained in the second image data and the dot area percentage of one of the process colors corresponding to the dot area percentage of the fluorescent color, where the dot area percentage of the process color corresponding to the color value indicated by the first image data is taken as 1, and the ratio is (1-α):α (0<distribution rate α<1).

4. 4. The image processing device according to claim 1, wherein the process color, the dot area ratio of which is distributed from the dot area ratio of the fluorescent color, is a homochromatic process color having an absorption spectrum peak close to an absorption spectrum peak of the fluorescent color among the process colors.

5. a first generating unit that distributes the dot area percentages of process colors of the same color system as the fluorescent color, which are included in a first profile that associates color values ​​in a predetermined color space with dot area percentages of process colors, to the dot area percentage of the fluorescent color by the distribution rate α, and generates a second profile that associates combinations of the dot area percentages of the process colors and the dot area percentages of the fluorescent color with color values ​​in the color space, the first image data includes process color dot percentages; 4. The image processing device according to claim 3, wherein the color conversion unit converts the dot area ratio of the process color of the first image data into a color value of the color space using the first profile, and converts the color value into the dot area ratio of the process color and the dot area ratio of the fluorescent color using the second profile, thereby converting into the second image data.

6. a second generation unit that obtains the dot area percentage of the process color corresponding to the color value of a predetermined color space corresponding to a target color of color sample information from a first profile that associates the color value of the color space with the dot area percentage of the process color, distributes the dot area percentage of the process color from the dot area percentage of a process color of the same color system as the fluorescent color to the dot area percentage of the fluorescent color by the distribution rate α, calculates the dot area percentage of the process color from the dot area percentage of the fluorescent color using color reproduction characteristics of the printing device, and generates a dictionary that associates the calculated combination of the dot area percentage of the process color and the dot area percentage of the fluorescent color with the target color, The first image data includes spot color information.

4. The image processing device according to claim 3, wherein the color conversion unit converts the spot color information of the first image data into a dot area ratio of a process color and a dot area ratio of the fluorescent color by using the dictionary, thereby converting the spot color information of the first image data into the second image data.

7. a second acquisition unit that acquires color values ​​measured by a colorimeter for a chart image including a plurality of types of charts printed out from the printing device; a generating unit that generates the color reproduction characteristic by associating the dot area ratios of the process colors of the chart image and the dot area ratios of the fluorescent colors with the color values ​​acquired by the second acquiring unit; The image processing device according to claim 6 , further comprising:

8. 8. The image processing device according to claim 3, wherein the distribution rate α is a fixed value.

9. The image processing device according to claim 8 , wherein the distribution rate α is 0.

4.

10. The image processing device according to claim 5 , wherein the first generating section calculates a saturation from a color value of the color space included in the first profile, and determines the distribution rate α in accordance with the saturation.

11. The image processing device according to claim 6 , wherein the second generating section calculates a saturation from a color value of the color space included in the first profile, and determines the distribution rate α in accordance with the saturation.

12. 2. The image processing device according to claim 1, wherein the color conversion unit changes a ratio m:n of the dot area rate of the one color m and the dot area rate of the fluorescent color n to m-m×γ:n+m×γ when the distribution rate is γ.

13. a third generating unit that distributes a dot area rate of the one color included in a first profile that associates a color value of a predetermined color space with a dot area rate of a process color to a dot area rate of the fluorescent color by the distribution rate, and generates a second profile that associates a combination of the dot area rate of the process color and the dot area rate of the fluorescent color with a color value of the color space, the first image data includes process color dot percentages; 13. The image processing device according to claim 1 or 12, wherein the color conversion unit converts the dot area ratio of the process color of the first image data into a color value of the color space using the first profile, and converts the color value into the dot area ratio of the process color and the dot area ratio of the fluorescent color using the second profile, thereby converting into the second image data.

14. 13. The image processing device according to claim 1, wherein the color conversion section derives the saturation using a dot percentage of the process color of the first image data.

15. 15. The image processing device according to claim 1, wherein the fluorescent color is fluorescent magenta.

16. An acquisition step of acquiring first image data to be subjected to color conversion; a color conversion step of converting the acquired first image data into second image data in which the dot area ratio of one of the process colors represented by the first image data is distributed to the dot area ratio of a fluorescent color different from the process color and the dot area ratio of the process color; having The color conversion step calculates the dot area rate of the one color and the dot area rate of the fluorescent color using a distribution rate that is positively correlated with saturation, the distribution rate being calculated based on the dot area rate of the process color of the first image data.

17. On the computer, An acquisition step of acquiring first image data to be subjected to color conversion; a color conversion step of converting the acquired first image data into second image data in which the dot area ratio of one of the process colors represented by the first image data is distributed to the dot area ratio of a fluorescent color different from the process color and the dot area ratio of the process color; Run the command, The color conversion step is a program for calculating the dot area rate of the one color and the dot area rate of the fluorescent color using a distribution rate that has a positive correlation with the saturation calculated based on the dot area rate of the process color of the first image data.

18. Acquire image data; an image processing device that calculates a dot area ratio as a value of one of the process colors and a dot area ratio as a value of a fluorescent color of the same color type as the one color based on the acquired image data, using a distribution rate that has a positive correlation with the saturation calculated from the saturation based on the dot area ratio of the process color and that has a positive correlation with the saturation.

19. 20. The image processing apparatus according to claim 18, wherein a value of fluorescent magenta as the fluorescent color of the same color family is calculated based on a value of magenta as the one color among the process colors.

20. 20. The image processing apparatus according to claim 19, wherein when forming an image of the image data, the fluorescent magenta value is used to form the image.

21. The image processing device according to any one of claims 18 to 20, wherein the value of the fluorescent color of the same color family is converted to a first value or a second value greater than the first value based on the value of the one color.

22. 21. The image processing apparatus according to claim 19, wherein the value of the fluorescent magenta is calculated by converting the value of the magenta to a first value or a second value greater than the first value.

23. 23. The image processing apparatus according to claim 18, wherein printing is performed using a fluorescent color material that is loaded according to the value of the fluorescent color of the same color family.

24. 23. The image processing apparatus according to claim 19, 20 or 22, wherein printing is performed using a loaded fluorescent magenta toner according to the value of the fluorescent magenta.

25. 25. The image processing device according to claim 18, wherein the value of the one color is calculated by distributing the value of the one color and the value of the fluorescent color of the same color system using an ICC color profile.

26. An acquisition step of acquiring image data; a calculation step of calculating a dot area ratio of one of the process colors and a dot area ratio of a fluorescent color of the same color type as the one color based on the acquired image data, using a distribution rate having a positive correlation with a saturation calculated from a value of the one of the process colors based on a dot area ratio of the one color; An image processing method comprising:

27. To the computer. An acquisition step of acquiring image data; a calculation step of calculating a dot area ratio of one of the process colors and a dot area ratio of a fluorescent color of the same color type as the one color based on the acquired image data, using a distribution rate having a positive correlation with a saturation calculated from a value of the one of the process colors based on a dot area ratio of the one color; A program for executing the above.

Images