JP4946908B2 - Print control apparatus, print system, and print control program - Google Patents

Description

  The present invention relates to a printing system and a printing control program, and more particularly to a printing system and a printing control program for reproducing a target.

A printing method focusing on spectral reproducibility has been proposed (see Patent Document 1). In this document, a printer color (CMYKOG) is used so as to fit a spectral reflectance (target spectrum) of a target using a printing model in order to perform printing that spectrally and colorimetrically matches a target image. The combination of is optimized. In this way, by performing printing based on the printer color (CMYKOG), the target image can be spectrally reproduced, and as a result, a highly reproducible printing result can be obtained.
Special table 2005-508125 gazette

  However, the types of color materials such as ink that can be used in a printing apparatus such as a printer are limited, and it is difficult to accurately reproduce the spectral reflectance of the target in all visible wavelength ranges. For this reason, there has been a case where the spectral reflectance fitting does not reach a sufficient level, and the color reproducibility remains insufficient. In particular, since the spectral reflectance was tried to fit to a wavelength range that hardly contributes to human vision, the reproducibility of the spectral reflectance in the wavelength range that greatly contributes to human vision is reduced. There was a problem that the reproducibility was felt poor. Furthermore, in the above-mentioned document, it is necessary to obtain the spectral reflectance of the target in advance, and there is a problem that a spectral reflectance meter that is not widely used is generally required.

  The present invention has been made in view of the above problems, and provides a printing system and a printing control program that ensure spectral reproducibility using a general image input apparatus.

  In order to solve the above problem, first, the input profile acquisition means acquires a plurality of input profiles that define the correspondence between color data obtained by image input in a predetermined image input device and color values under a plurality of light sources. To do. That is, an input profile that defines a correspondence relationship between color data obtained by inputting an image of an arbitrary object using the image input device and color values when the same object is measured under a plurality of light sources is acquired. Then, the target color value acquisition unit converts color data obtained by inputting an image of the target with the image input device according to each of the plurality of input profiles. Thereby, the color value which the target shows under a plurality of light sources can be obtained, and the color value is acquired as the target color value.

  The printing control means predicts the color material amount set that reproduces on the recording medium a color value that approximates the target color value under a plurality of light sources. At that time, an evaluation value for evaluating the closeness to the target color value under each light source is used. Then, the printing apparatus is caused to execute printing by designating the color material amount set that reproduces the color value approximate to the target color value on the recording medium under each light source. According to the color material amount set that reproduces on the recording medium a color value that approximates the target color value under a plurality of light sources, a visually reproducible print result can be obtained under each light source. In addition, by performing printing based on the color material amount set that can realize the closeness to the target color value not only with a single light source but also with a plurality of light sources, the reproducibility of spectral reflectance is similar as a result. Become. Note that it is sufficient that the printing apparatus can attach at least a plurality of the color materials to the recording medium, and the present invention can be applied to various printing apparatuses such as an ink jet printer, a laser printer, and a sublimation printer.

  In addition, as the image input device, it is also possible to use a scanner or a digital (still / video) camera that is widely used. For example, in the case of a flatbed scanner, ambient light is substantially blocked, image input can be performed under constant illumination light, and stable color data can be measured. However, in the case of a digital camera, even if a flash is used, the ambient light affects the color data, and the ambient light also affects the target color value obtained by converting the color data using the input profile. Therefore, it is desirable to correct the color data or the target color value converted by a plurality of the input profiles in accordance with the ambient light at the time of image input by the image input device. If the color data is corrected, the target color value finally converted is also corrected. Therefore, the color data may be corrected, or the target color value may be directly corrected.

  Further, as an example of means for easily specifying the ambient light, the ambient light is specified based on color data obtained by inputting an image of a reference color patch having a known color value with the image input device. May be. That is, by inputting an image of the reference color patch whose color value is known together with the target, it is possible to determine how the reference color patch whose color value is known is affected by ambient light. . Therefore, the target color value in which the influence of the ambient light at the time of image input is suppressed can be obtained by performing a correction that cancels the influence. The reference color patch may be any color as long as the color value is known. Further, the reference color patch may be singular or plural. For example, by adopting the reference color patch indicating white, the color due to ambient light can be corrected. Of course, a plurality of the reference color patches that cover the entire color space may be prepared, and appropriate correction may be performed for the entire color space.

  Furthermore, the technical idea of the present invention can be realized not only by a specific printing control apparatus but also by a method thereof. That is, the present invention can also be specified as a method having steps corresponding to the respective units performed by the above-described print control apparatus. Of course, when the above-described printing control apparatus reads the program and realizes each means described above, the technical features of the present invention can be applied to a program for executing a function corresponding to each means and various recording media on which the program is recorded. It goes without saying that the idea can be embodied. Needless to say, the print control apparatus of the present invention can be distributed not only by a single apparatus but also by a plurality of apparatuses. For example, each unit included in the print control apparatus can be distributed in both the printer driver executed on the personal computer and the printer. In addition, each unit of the print control apparatus of the present invention can be included in a printing apparatus such as a printer.

Hereinafter, embodiments of the present invention will be described in the following order.
1. Configuration of print control device:
2. Print data generation processing:
3. Print control processing:
3-1.1 D-LUT creation processing:
3-2. Print control data generation processing:
4). Spectral printing model:
5. Variations:
5-1. Modification 1:
5-2. Modification 2:
5-3. Modification 3:
5-4. Modification 4:
5-5. Modification 5:

1. Configuration of Print Control Device FIG. 1 shows a hardware configuration of a print control device according to an embodiment of the present invention. In FIG. 1, the print control apparatus is mainly composed of a computer 10, and the computer 10 includes a CPU 11, a RAM 12, a ROM 13, a hard disk drive (HDD) 14, a general-purpose interface (GIF) 15, a video interface (VIF) 16, and an input interface. (IIF) 17 and a bus 18. The bus 18 implements data communication between the elements 11 to 17 constituting the computer 10, and communication is controlled by a chip set (not shown). The HDD 14 stores program data 14a for executing various programs including an operating system (OS), and the CPU 11 executes calculations according to the program data 14a while expanding the program data 14a in the RAM 12. . Further, the HDD 14 has five input ICC profiles corresponding to each of five types of light sources (standard daylight D50 light source, D55 light source, D65 light source, incandescent bulb A light source, and fluorescent lamp F11 light source). SIP1 to SIP5 are stored. The GIF 15 provides an interface conforming to the USB standard, for example, and connects an external printer 20 and a scanner 30 (image input device) to the computer 10. The VIF 16 connects the computer 10 to an external display 40 and provides an interface for displaying an image on the display 40. The IIF 17 connects the computer 10 to an external keyboard 50a and a mouse 50b, and provides an interface for the computer 10 to acquire input signals from the keyboard 50a and the mouse 50b.

  FIG. 2 shows a software configuration of a program executed by the computer 10 together with a schematic data flow. In the figure, in the computer 10, an OS P1, a sample printing application (APL) P2, a printer driver (PDV) P3, a scanner driver (SDV) P4, and a display driver (DDV) P5 are mainly executed. The OS P1 provides an image equipment interface (GDI) P1a and a spooler P1b as one of APIs that can be used by each program. The GDI P1a is called in response to a request from the APL P2, and further in response to a request from the GDI P1a. PDV P3 and DDV P5 are called. The GDI P1a provides a general-purpose mechanism for the computer 10 to control image output in an image output device such as the printer 20 or the display 40, while the PDV P3 or DDV P5 is a process specific to the model of the printer 20 or the display 40. Etc. The spooler P1b is interposed between the APL P2, the PDV P3, and the printer 20, and executes job control and the like. APL P2 is an application program for printing the sample chart SC, generates print data PD in the RGB bitmap format, and outputs the print data PD to the GDI P1a. In generating the print data PD, the target color data DD is acquired from the SDV P4. The SDV P4 controls the scanner 30 in response to a request from the APL P2, and outputs the color data DD obtained by the control to the APL P2.

  The print data PD generated by the APL P2 is output to the PDV P3 via the GDI P1a and the spooler P1b, and the PDV P3 executes processing for generating print control data CD that can be output to the printer 20 based on the print data PD. . The print control data CD generated by the PDV P3 is output to the printer 20 via the spooler P1b provided by the OS P1, and the printer 20 performs an operation based on the print control data CD to print the sample chart SC on the printing paper. Let Although the overall processing flow has been schematically described above, the processing executed by each of the programs P1 to P4 will be described in detail below using a flowchart.

2. Print Data Generation Processing FIG. 3 shows the flow of print data generation processing executed by APL P2. As shown in FIG. 2, the APL P2 includes a UI unit (UIM) P2a, a measurement control unit (MCM) P2b, and a print data generation unit (PDG) P2c. These modules P2a, P2b, and P2c are shown in FIG. Each step shown in 3 is executed. The PDG P2c includes an input profile acquisition unit (IPG) P2c1 and a target color value acquisition unit (TCG) P2c2. In step S100, the UIM P2a displays a UI screen for accepting a print instruction to print the sample chart SC via the GDI P1a and the DDV P5. On the UI screen, a display showing a template of the sample chart SC is provided.

  FIG. 4 shows an example of the UI screen. In the figure, the template TP is displayed, and the template TP is provided with 12 frames FL1 to FL12 for laying out color patches. Each frame FL1 to FL12 can be selected by clicking the mouse 50b on the UI screen, and a selection window W for instructing whether to start scanning is displayed when the frames FL1 to FL12 are clicked. Is done. The UI screen is also provided with a button B for instructing whether or not to print the sample chart SC. In step S110, the UIM P2a detects a click on each frame FL1 to FL12 by the mouse 50b, and if it is detected, a selection window W for instructing whether to start scanning is displayed in step S120. . In step S130, a click on the mouse 50b in the selection window W is detected. If cancel is clicked, the process returns to step S110. On the other hand, when the scan execution is clicked, in step S135, the UIM P2a performs display for guiding the scan. In this display, a display for prompting the user to set the target TG on the document table of the scanner 30 and a scan execution button for instructing execution of the scan after setting the target TG on the document table of the scanner 30 are provided. .

  In this embodiment, the target TG for colorimetry is an object surface that is a target for spectral reproduction. For example, an artificial object surface formed by another printing apparatus or a coating apparatus, a natural object surface, or the like is used. Applicable. In step S140, a scan is executed for a certain target TG. The scanner 30 of the present embodiment is a flat bed type scanner, and the ambient light is blocked by placing the target TG on the document table and covering the cover. Then, during scanning, the target TG is irradiated with predetermined illumination light, and the reflected light is imaged by the imaging device, whereby the color data DD is acquired. In the scanner 30 of the present embodiment, the color space of the color data DD output to the outside is an RGB color space, and the color data DD is represented by RGB values in the RGB color space. The RGB color space is a color space that depends on the device characteristics of the scanner 30. In step S142, the IPG P2c1 acquires five input ICC profiles SIP1 to SIP5 from the HDD 14.

FIG. 5 schematically illustrates the input ICC profiles SIP1 to SIP5. The input ICC profiles SIP1 to SIP5 are look-up tables that define the correspondence between the RGB color space of the scanner 30 and the CIELAB color space, and L ^{* of the} CIELAB color space corresponding to a plurality of grid points in the RGB color space ^. a ^* b ^* value (color value) is described. Note that the input ICC profiles SIP1 to SIP5 do not need to be look-up tables, and may be given by determinants or the like. In the input ICC profile SIP1 corresponding to the D50 light source, the RGB value (lattice point) of the predetermined color patch CP measured by the scanner 30 and L measured by the colorimeter while irradiating the color patch CP with the D50 light source. Correspondences with ^* a ^* b ^* values are described. Also in the other input ICC profiles SIP2 to SIP5, the RGB value (grid point) measured by the scanner 30 for the predetermined color patch CP and the color patch CP are irradiated with the D55 light source, the D65 light source, the A light source, and the F11 light source, respectively. The correspondence relationship with the L ^* a ^* b ^* values measured by the colorimeter is described. In step S143, the TCG P2c2 uses the input ICC profiles SIP1 to SIP5 as described above to convert the RGB values of the target TG obtained by scanning into L ^* a ^* b ^* values, respectively. Get the value.

FIG. 6 schematically shows how the target color value is acquired in step S143. In the figure, the RGB values obtained by scanning in step S140 are converted into L ^* a ^* b ^* values by each of the input ICC profiles SIP1 to SIP5. The L ^* a ^* b ^* value converted by the input ICC profile SIP1 is a color value obtained by measuring the color when the target TG is observed under the D50 light source with the colorimeter. Similarly, the L ^* a ^* b ^* values converted by the input ICC profiles SIP2 to SIP5 are measured by the colorimeter when the target TG is irradiated with the D55 light source, D65 light source, A light source, and F11 light source, respectively. Color value. As described above, when five L ^* a ^* b ^* values are obtained when the target TG is observed with five light sources, the TCG P2c2 acquires the L ^* a ^* b ^* values as target color values.

  Further, the target color value of the D65 light source, which is the most standard light source, is converted into an RGB value using a predetermined RGB profile, and the RGB value is acquired as a display RGB value. The RGB profile is a profile that defines a color matching relationship between the CIELAB color space as an absolute color space and the RGB color space of the present embodiment. In step S145, the clicked frames FL1 to FL12 in the template TP are updated to a display filled with the display RGB values. As a result, the color of the target TG with the D65 light source, which is a standard light source, can be sensed on the UI screen. When step S145 is completed, a unique index is generated in step S150, and the index, the display RGB value, and the position information of the frames FL1 to FL12 clicked in step S110 are displayed as five target color values. Are stored in the RAM 12 in association with When step S150 is completed, the process returns to step S110, and steps S120 to S150 are repeatedly executed. As a result, the other frames FL1 to FL12 can be selected, and other targets TG can be scanned for the other frames FL1 to FL12. In the present embodiment, twelve different types of targets TG1 to TG12 are prepared, and target color values with five types of light sources are acquired for each of the targets TG1 to TG12. Accordingly, in step S150, data in which the five target color values, the unique indexes, and the display RGB values are associated with each other for each frame FL1 to FL12 is sequentially stored in the RAM. The index only needs to be generated so that each value is unique. The index may be generated by increment or by a random number that does not overlap.

  FIG. 7 shows a state where target color values obtained for a certain target TG are plotted in the CIELAB color space. As shown in the figure, even when a single target TG is scanned, different target color values are acquired depending on the input ICC profiles SIP1 to SIP5 used for the conversion. As described above, a phenomenon in which the target color values are different under a plurality of light sources is referred to as metamerism, and has different metamerism characteristics for each target TG. This metamerism depends on the spectral reflectance R (λ) of each target, and even if targets having the same target color value are obtained with a certain light source, the spectral reflectance R (λ) is different. Different target color values will be shown under other light sources. Since the input ICC profiles SIP1 to SIP5 are created based on the colorimetric values of the color patch CP shown in FIG. 5 under each light source, the light source dependency of the color patch CP and the target TG is determined. It can be said that the more similar the characteristics, the more accurate the target color value converted by the input ICC profiles SIP1 to SIP5. For example, when the target TG is a printed material, it is desirable to form a color patch for creating the input ICC profiles SIP1 to SIP5 with the same color material as the target TG.

FIG. 8 illustrates how the colorimetric values under a plurality of light sources are obtained from a target TG having a certain spectral reflectance. For example, a target TG has a target spectral reflectance R _t (λ) distribution that is not uniform in the entire visible wavelength region as shown in the figure. On the other hand, each light source has a different distribution of spectral energy P (λ), and the spectral energy of the reflected light of each wavelength when the target TG is irradiated with the D65 light source is the target spectral reflectance R _t (λ). And spectral energy P (λ) multiplied by each wavelength. Further, the spectral energy spectrum of the reflected light is convolved with the color matching functions x (λ), y (λ), z (λ) corresponding to the human spectral sensitivity characteristics, and normalized by the coefficient k. Thus, tristimulus values X, Y, and Z can be obtained. The above is expressed by the following equation (1).

By converting the tristimulus values X, Y, and Z by a predetermined conversion formula, L ^* a ^* b ^* values as color values can be obtained. As described above, at the time of the spectrum of the spectral energy of the reflected light, a different spectrum is generated for each light source, so that the finally obtained target color value also differs depending on the light source as shown in FIG. It becomes.

  In step S110, if a click on each of the frames FL1 to FL12 is not detected, a click on button B for executing printing of sample chart SC is detected in step S160, and if not detected, the process returns to step S110. On the other hand, if it is detected that the button B for executing printing of the sample chart SC is detected, the PDG P2c generates print data PD in step S170.

  FIG. 9 schematically shows the configuration of the print data PD. In the figure, the print data PD is composed of a large number of pixels arranged in a dot matrix, and each pixel has 4 bytes (8 bits × 4) of information. The print data PD shows an image similar to the template TP shown in FIG. 4, and the pixels other than the regions corresponding to the frames FL1 to FL12 of the template TP have RGB values of colors corresponding to the template TP. ing. The gradation value of each RGB channel is expressed by 8 bits (256 gradations), and 3 bytes out of the 4 bytes described above are used to store the RGB values. For example, when colors other than the frames FL1 to FL12 of the template TP are expressed by uniform intermediate gray of (R, G, B) = (128, 128, 128), the frames FL1 to FL12 in the print data PD. Pixels other than the region corresponding to the color information of (R, G, B) = (128, 128, 128). The remaining 1 byte is not used.

  On the other hand, the pixels corresponding to the frames FL1 to FL12 of the template TP also have 4-byte information, and the index is usually stored using 3 bytes in which RGB values are stored. This index is unique for each of the frames FL1 to FL12 in step S150, and the PDG P2c acquires the index from the RAM 12 and stores the index corresponding to the pixel corresponding to each of the frames FL1 to FL12. For the pixels corresponding to the frames FL1 to FL12 in which the indexes are stored instead of the RGB values in this way, the flag indicating that the indexes are stored is set using the remaining 1 byte. This makes it possible to determine whether each pixel stores an RGB value or an index. In this embodiment, since 3 bytes can be used to store the index, it is necessary to generate an index that can be expressed with an information amount of 3 bytes or less in step S150. When the bitmap format print data PD can be generated as described above, the PDG P2c generates the index table IDB in step S180.

  FIG. 10 shows an example of the index table IDB. In the figure, for each unique index generated corresponding to each frame FL1 to FL12, the target color value for each light source obtained by scanning and conversion of the input ICC profiles SIP1 to SIP5 and the target in the D65 light source The display RGB values corresponding to the color values are stored. When the generation of the index table IDB is completed, the print data PD is output to the PDV P3 via the GDI P1a and the spooler P1b. Since the print data PD is not different from the normal RGB bitmap format in appearance, the GDI P1a and the spooler P1b provided by the OS P1 can be processed in the same manner as a normal print job. On the other hand, the index table IDB is directly output to the PDV P3. In the present embodiment, the index table IDB is newly generated. However, a new correspondence between the index, the target color value, and the display RGB value may be added to the existing index table IDB. . The print data generation process and the print control process described later do not necessarily have to be executed consecutively in the same apparatus, and the print data generation process and the print control process are connected by a communication line such as a LAN or the Internet. It may be executed individually on a plurality of computers.

3. Print Control Process FIG. 11 shows the overall flow of the print control process executed by the PDV P3. As shown in FIG. 2, the PDV P3 includes a 1D-LUT generation unit (LUG) P3a and a print control data generation unit (CDG) P3b, and performs the 1D-LUT generation process (step S200) shown in FIG. The LUG P3a is in charge, and the CDG P3b is in charge of one print control data generation process (step S300). The 1D-LUT generation process may be performed prior to the print control data generation process, or the 1D-LUT generation process and the print control data generation process may be performed in parallel.

3-1.1 D-LUT Generation Processing FIG. 12 shows the flow of 1D-LUT generation processing. As shown in FIG. 2, the LUG P3a includes an ink amount set calculation module (ICM) P3a1, a spectral reflectance prediction module (RPM) P3a2, a color calculation module (CCM) P3a3, an evaluation value calculation module (ECM) P3a4, and an LUT output module. (LOM) P3a5. In step S210, ICM P3a1 acquires the index table IDB. In step S220, one index is selected from the index table IDB, and the target color value associated with the index is acquired. In step S230, the ICM P3a1 performs a process of calculating an ink amount set that can reproduce the same color as the target color value. At that time, the above-described RPM P3a2, CCM P3a3, and ECM P3a4 are used.

FIG. 13 schematically shows the flow of processing for calculating an ink amount set that can reproduce the same color as the target color value. In response to the input of the ink amount set φ from the ICM P3a1, the RPM P3a2 predicts the spectral reflectance R (λ) when the printer 20 ejects ink onto a predetermined print sheet based on the ink amount set φ. The predicted spectral reflectance R _s (λ) is predicted, and the predicted spectral reflectance R _s (λ) is output to the CCM P3a3. The printer 20 of the present embodiment is an ink jet printer, and performs printing by ejecting C (cyan) M (magenta) Y (yellow) K (black) lc (light cyan) lm (light magenta) ink onto printing paper. . The ink amount set φ means a combination of ink amounts d _C , d _M , d _Y , d _K , d _lc , and d _lm of the CMYKlclm ink to be ejected. If the ink amount set φ is designated, the formation state of each ink dot on the printing paper can be predicted, so the RPM P3a2 can uniquely calculate the predicted spectral reflectance R _s (λ). For the prediction model (spectral printing model) applied by RPM P3a2, see 4. This will be explained in detail in the section.

When the predicted spectral reflectance R _s (λ) is obtained, the CCM P3a3 calculates a predicted color value when the object having the predicted spectral reflectance R _s (λ) is irradiated with the five light sources described above. Here, the L ^* a ^* b ^* value of the CIELAB color space is calculated as the predicted color value. The flow of calculating the predicted color value is the same as that shown in FIG. 8 and the above equation (1) (the target spectral reflectance R _t (λ) is replaced with the predicted spectral reflectance R _s (λ)). is there. That is, by multiplying the predicted spectral reflectance R _s (λ) by the spectrum of the spectral energy of each light source, performing convolution integration with a color matching function, and further converting the tristimulus values into L ^* a ^* b ^* values, The L ^* a ^* b ^* value as the predicted color value can be calculated. The predicted color value is calculated for each of the five light sources, and the predicted color value is output to the ECM P3a4.

The ECM P3a4 calculates a color difference ΔE between the target color value and the predicted color value for each light source. In this embodiment, the color difference ΔE (ΔE ₂₀₀₀ ) is calculated based on the color difference formula of CIE DE2000. In addition, the color difference for each light source is expressed as ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , ΔE _F11 . When ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , and ΔE _F11 can be calculated for the color differences for each light source, the evaluation value E (φ) is calculated by the following equation (2).

In the above equation (2), w _{1 to} w ₅ are weighting factors for setting the weight of each light source. In this embodiment, w ₁ = w ₂ = w ₃ = w ₄ = w ₅ Shall be equalized. The evaluation value E (φ) is a value that decreases as the color differences ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , and ΔE _F11 for each light source decrease, and the target colorimetric value and the predicted color value are comprehensive for each light source. The closer it is to, the smaller the value. The calculated evaluation value E (φ) is returned to the ICMP 3a1. That is, the ICMP 3a1 outputs an arbitrary ink amount set φ to the RPM P3a2, the CCM P3a3, and the ECM P3a4, so that the evaluation value E (φ) is finally returned to the ICMP 3a1. The ICM P3a1 repeatedly executes to obtain the evaluation value E (φ) corresponding to an arbitrary ink amount set φ, so that the evaluation value E (φ) as the objective function is minimized. Calculate the optimal solution. As a method for calculating the optimum solution, for example, a nonlinear optimization method such as a gradient method can be used.

FIG. 14 schematically shows how the ink amount set φ is optimized in step S230. In the same figure, the transition of the target color value under each light source indicated by the target TG in the CIELAB color space and the predicted color value under each light source when the ink amount set φ is optimized is shown. According to the equation (2), since the color differences ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , and ΔE _F11 for all light sources can be reduced as an optimization condition, The ink amount set φ is optimized so that the color differences ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , ΔE _F11 under the light source are gradually reduced. In this way, it is possible to calculate an ink amount set φ that can be reproduced by the printer 20 with an appearance similar to that of the target TG in any light source. Note that the optimization termination condition may be the number of repetitions of the ink amount set φ update or the threshold value of the evaluation value E (φ).

  As described above, when the ICM P3a1 calculates the ink amount set φ that can reproduce the same color as the target color value in step S230, all the indexes described in the index table IDB in step S240 are all in step S220. In step S220, the process returns to step S220 to select the next index. In this way, it is possible to calculate the ink amount set φ that can reproduce the same color as the target color value for all indexes. That is, it is possible to calculate the ink amount set φ that can reproduce the same color as the target color value for all the targets TG1 to TG12 scanned in step S140 of the print data generation process (FIG. 2). If it is determined in step S240 that the optimal ink amount set φ has been calculated for all indexes, the LOM P3a5 generates a 1D-LUT and outputs the 1D-LUT to the CDG P3b in step S250.

  FIG. 15 shows an example of a 1D-LUT. In the figure, an optimum ink amount set φ is stored corresponding to each index. That is, for each target TG1 to TG12, a 1D-LUT describing an ink amount set φ that can be reproduced by the printer 20 with an appearance similar to that of each target TG1 to TG12 can be prepared. When the 1D-LUT is output to the CDG P3b, the 1D-LUT generation process is completed, and the next print control data generation process (step S300) is executed.

3-2. Print Control Data Generation Processing FIG. 16 shows the flow of print control data generation processing. As shown in FIG. 2, the CDG P3b includes a mode discrimination module (MIM) P3b1, an index separation module (ISM) P3b2, an RGB separation module (CSM) P3b3, a halftone module (HTM) P3b4, and a rasterization module (RTM). P3b5. In step S310, the mode determination module (MIM) P3b1 acquires the print data PD. In step S320, the MIM P3b1 selects one pixel from the print data PD. In step S330, the MIM P3b1 determines whether or not a flag indicating that the index is stored in the selected pixel is set. If it is determined that the flag is not raised, the CSM P3b3 refers to the 3D-LUT in step S340 and executes color conversion (separation) for the pixel.

FIG. 17 shows an example of a 3D-LUT. In the figure, the 3D-LUT describes a plurality of representative coordinates in the color space in which the correspondence between the RGB value and the ink amount set φ (d _C , d _M , d _Y , d _K , d _lc , d _lm ). The CSM P3b3 refers to the 3D-LUT and acquires the ink amount set φ corresponding to the RGB value of the pixel. At that time, the corresponding ink amount set φ is acquired by performing interpolation calculation for RGB values not directly described in the 3D-LUT. As a method for creating a 3D-LUT, JP 2006-82460 A or the like can be employed. In this publication, a 3D-LUT in which color reproducibility in a specific light source, gradation of reproducible color, graininess, light source independence of reproducible color, gamut, and ink duty are comprehensively improved. Is created.

  On the other hand, if it is determined in step S330 that the flag indicating that the index has been stored in the selected pixel is set, ISM P3b2 refers to the 1D-LUT in step S350, and the color for the pixel is determined. Perform conversion (separation). That is, the index is acquired from the pixel on which the flag indicating that the index is stored, and the ink amount set φ associated with the index is acquired by the 1D-LUT. In step S340 or step S350, if the ink amount set φ for the pixel can be acquired, it is determined in step S360 whether the ink amount set φ has been acquired for all the pixels. If there remains a pixel for which the ink amount set φ has not been acquired, the process returns to step S320 to select the next pixel.

  By repeatedly executing the above processing, the ink amount set φ can be obtained for all the pixels. When the ink amount set φ can be obtained for all the pixels, all the pixels are converted into the print data PD expressed by the ink amount set φ. As described above, by determining which one of the 1D-LUT and 3D-LUT is used for each pixel, with respect to the pixels corresponding to the frames F1 to F12 in which the index is stored, the respective light sources have the respective targets TG1 to TG12. Can be obtained, and color reproduction based on a 3D-LUT creation guideline (for example, emphasizing graininess) is performed for pixels storing RGB values. A possible ink amount set φ can be acquired.

  In step S370, the HTM P3b4 acquires print data PD in which each pixel is expressed by an ink amount set φ, and executes halftone processing. The HTM P3b4 can use a known dither method, error diffusion method, or the like for halftone processing. In the print data PD for which the halftone process has been completed, each pixel has an ejection signal indicating whether or not each ink is ejected. In step S380, the RTM P3b5 acquires the print data PD for which the halftone process is completed, and executes a process of assigning the ejection signal in the print data PD to each scan pass and each nozzle of the print head of the printer 20. As described above, the print control data CD that can be output to the printer 20 can be generated, and the print control data CD to which signals necessary for controlling the printer 20 are attached is output to the spooler P1b and the printer 20. As a result, the printer 20 ejects ink onto the printing paper to form a sample chart SC.

  As described above, the colors of the targets TG1 to TG12 can be reproduced in the region corresponding to the frames FL1 to FL12 of the sample chart SC formed on the printing paper. Further, since the areas corresponding to the frames FL1 to FL12 are printed with an ink amount set φ that follows the target color values under the plurality of light sources of the targets TG1 to TG12, the areas TG1 to TG12 Similar colors can be reproduced. That is, the color of the area corresponding to each of the frames FL1 to FL12 when the sample chart SC is viewed indoors reproduces the color when the targets TG1 to TG12 are viewed indoors, and when the sample chart SC is viewed outdoors. The colors of the regions corresponding to the frames FL1 to FL12 can be reproduced when the targets TG1 to TG12 are visually recognized outdoors. That is, it is possible to create a sample chart SC that does not select an observation light source.

  Ultimately, if the sample chart SC having the same spectral reflectance R (λ) as the targets TG1 to TG12 is reproduced, the same color as the targets TG1 to TG12 can be reproduced with any light source. . However, since the ink (color material type) that can be used by the printer 20 is limited to CMYKlclm, an ink amount set φ that can reproduce the same spectral reflectance R (λ) as the targets TG1 to TG12 is obtained. Is virtually impossible. In addition, even when the ink amount set φ that can reproduce the spectral reflectance R (λ) similar to the targets TG1 to TG12 is obtained in the wavelength range that does not affect the perceived color, it is useless in realizing the visual reproduction accuracy. . On the other hand, in the present invention, the requirement for optimizing the ink amount set φ is relaxed by visually obtaining the ink amount set φ that can reproduce the target color values under a plurality of realistic light sources, and visually. Sufficient accuracy can be achieved.

  On the other hand, in the region corresponding to the frames FL1 to FL12 of the sample chart SC formed on the printing paper, printing is performed with the ink amount set φ based on the 3D-LUT described above. For this reason, the printing performance for the area is based on the 3D-LUT. As described above, in the present embodiment, the area other than the frames FL1 to FL12 shows a uniform image of intermediate gray, but the printing performance targeted by the 3D-LUT can be satisfied in the area. That is, it is possible to realize printing in which the gradation of reproduced color, graininess, light source independence of reproduced color, gamut, and ink duty are comprehensively improved.

4). Spectral Printing Model FIG. 18 schematically shows the printing method of the printer 20 of this embodiment. In the figure, the printer 20 includes a print head 21 having a plurality of nozzles 21a, 21a,... For each CMYKlclm ink, and the amount of ink for each CMYKlclm ink ejected by the nozzles 21a, 21a,. There ink amount set φ mentioned above _{(d c, d m, d} y, d k, d lc, d lm) is controlled to an amount that conforms to be done on the basis of the print control data CD. The ink droplets ejected by the nozzles 21a, 21a,... Become fine dots on the printing paper, and an ink amount set φ (d _c , d _m , d _y , d _k , d _lc , d A print image having an ink coverage corresponding to _lm ) is formed on the printing paper.

Prediction model RPM P3a2 uses (spectral printing model), any ink amount set φ that can be used in the printer 20 of the embodiment _{(d c, d m, d} y, d k, d lc, d lm) in This is a prediction model for predicting the spectral reflectance R (λ) when printing is performed as the predicted spectral reflectance R _s (λ). In the spectral printing model, a spectral reflectance database RDB obtained by actually printing color patches at a plurality of representative points in the ink amount space and measuring the spectral reflectance R (λ) with a spectral reflectance meter is used. prepare. An arbitrary ink amount set φ (d _c , d) is accurately obtained by performing prediction based on the Cellular Yule-Nielsen Spectral Neugebauer Model using the spectral reflectance database RDB. _{m, d y, d k,} d lc, predicts the predicted spectral reflectance in the case of performing printing with _{d lm) R s (λ)} .

FIG. 19 shows the spectral reflectance database RDB. (Is a six-dimensional in the present embodiment, illustrated only CM surface. For ease of illustration) the spectral reflectance database RDB as shown in the figure ink amount space ink amount set of grid points in (d _c , D _m , d _y , d _k , d _lc , d _lm ) are look-up tables in which spectral reflectances R (λ) obtained by actually printing / measuring are described. For example, five grid points that divide each ink amount axis are generated. Here 5 ¹³ also lattice points are generated, it is necessary to print / measurement of color patches of huge amount, actually can be discharged simultaneously mountable ink number and simultaneously by the printer 20 ink Since the duty is limited, the number of grid points to be printed / measured is reduced.

  Further, only some of the lattice points are actually printed / measured, and the other lattice points are spectrally reflected R (λ) based on the spectral reflectance R (λ) of the actually printed / measured lattice points. Thus, the number of color patches that are actually printed / measured may be reduced. The spectral reflectance database RDB needs to be prepared for each printing sheet that can be printed by the printer 20. Strictly speaking, the spectral reflectance R (λ) is determined by the spectral transmittance of the ink film (dot) formed on the printing paper and the reflectance of the printing paper, and the surface physical properties of the printing paper (depending on the dot shape). ) And reflectivity. Next, prediction by the cell division Yule-Nielsen spectral Neugebauer model using the spectral reflectance database RDB will be described.

  The RPM P3a2 executes prediction based on the cell division Yule-Nielsen spectral Neugebauer model using the spectral reflectance database RDB in response to a request from the ICM P3a1. In this prediction, a prediction condition is acquired from ICM P3a1, and this prediction condition is set. Specifically, printing paper and ink amount set φ are set as printing conditions. For example, when prediction is performed using glossy paper as a printing paper, a spectral reflectance database RDB created by printing color patches on glossy paper is set.

When it is set in the spectral reflectance database RDB, ink amount sets input from ICM P3a1 phi applying _{(d c, d m, d} y, d k, d lc, d lm) of the spectral printing model. The cell splitting Yule-Nielsen spectroscopic Neugebauer model is based on the well-known spectroscopic Neugebauer model and the Yule-Nielsen model. In the following description, for simplification of description, a model in which three types of CMY inks are used will be described. However, a similar model is used as a model using an arbitrary ink set including CMYKlclm of the present embodiment. It is easy to expand. For cell division Yule-Nielsen spectral Neugebauer model, Color Res Appl 25, 4-19, 2000 and R Balasubramanian, Optimization of the spectral Neugebauer model for printer characterization, J. Electronic Imaging 8 (2), 156- See 166 (1999).

ここで、ａ_iはｉ番目の領域の面積率であり、Ｒ_i（λ）はｉ番目の領域の分光反射率である。添え字ｉは、インクの無い領域（ｗ）と、シアンインクのみの領域（ｃ）と、マゼンタインクのみの領域（ｍ）と、イエローインクのみの領域（ｙ）と、マゼンタインクとイエローインクが吐出される領域（ｒ）と、イエローインクとシアンインクが吐出される領域（ｇ）と、シアンインクとマゼンタインクが吐出される領域（ｂ）と、ＣＭＹの３つのインクが吐出される領域（ｋ）をそれぞれ意味している。また、ｆ_c，ｆ_m，ｆ_yは、ＣＭＹ各インクを１種類のみ吐出したときにそのインクで覆われる面積の割合（「インク被覆率(Ink area coverage)」と呼ぶ）である。 FIG. 20 is a diagram showing a spectral Neugebauer model. The spectral Neugebauer model, optional ink amount sets _{(d c, d m, d} y) predicted spectral reflectance of the printed matter when printed with R _s (lambda) is given by the following equation (3).

Here, a _i is the area ratio of the i-th region, and R _i (λ) is the spectral reflectance of the i-th region. The subscript i includes an area without ink (w), an area only with cyan ink (c), an area only with magenta ink (m), an area only with yellow ink (y), magenta ink and yellow ink. A region (r) where yellow ink and cyan ink are ejected, a region (b) where cyan ink and magenta ink are ejected, and a region where three inks CMY are ejected (region) (r) k) respectively. Further, f _c , f _m , and _fy are the proportions of the area covered with only one CMY ink when it is ejected (referred to as “Ink area coverage”).

The ink coverages f _c , f _m , and _fy are given by the Murray-Davis model shown in FIG. In the Murray-Davies model, for example, the ink area coverage f _c of the cyan ink is a nonlinear function of the ink amount d _c of the cyan, be converted to the ink amount d _c in the ink coverage f _c, for example by one-dimensional lookup table Can do. Ink coverage f _c, f _m, f _y is the ink amount d _c, d _m, reason for the non-linear function of d _y is spread enough ink in the case where a small amount of ink ejected to the unit area, This is because, when a large amount of ink is ejected, the ink is overlapped and the area covered with the ink does not increase so much. The same applies to other types of MY inks.

ここで、ｎは１以上の所定の係数であり、例えばｎ＝１０に設定することができる。（４ａ）式および（４ｂ）式は、ユール・ニールセン分光ノイゲバウアモデル(Yule-Nielsen Spectral Neugebauer Model)を表す式である。 When the Yule-Nielsen model for the spectral reflectance is applied, the equation (3) can be rewritten as the following equation (4a) or (4b).

Here, n is a predetermined coefficient of 1 or more, and can be set to n = 10, for example. Equations (4a) and (4b) are equations representing the Yule-Nielsen Spectral Neugebauer Model.

  The Cellular Yule-Nielsen Spectral Neugebauer Model used in the present embodiment is obtained by dividing the ink amount space of the above-described Yule-Nielsen Spectral Neugebauer Model into a plurality of cells. is there.

FIG. 21A shows an example of cell division in the cell division Yule-Nielsen spectroscopic Neugebauer model. Here, for simplification of description depicts the cell division in a two-dimensional ink amount space including two axes of the ink amount d _c, d _m of the CM inks. Note that it for ink coverage f _c, is f _m with at Murray-Davis model described above the ink amount d _c, a unique relationship with d _m, the ink coverage f _c, also be considered as an axis indicating the f _m . White circles are cell division grid points (called “lattice points”), and a two-dimensional ink amount (coverage) space is divided into nine cells C1 to C9. The ink amount set (d _c , d _m ) corresponding to each lattice point is an ink amount set corresponding to the lattice point defined in the spectral reflectance database RDB. That is, the spectral reflectance R (λ) of each lattice point can be obtained by referring to the above-described spectral reflectance database RDB. Therefore, the spectral reflectances R (λ) ₀₀ , R (λ) ₁₀ , R (λ) ₂₀ ... R (λ) ₃₃ of each lattice point can be acquired from the spectral reflectance database RDB.

In fact, performs six-dimensional ink amount space of even the cell division CMYKlclm In this embodiment, the ink amount set phi (d _c coordinates also the six-dimensional lattice _{points, d m, d y, d} k, d lc , D _lm ). Then, the ink amount set φ for each grid point _{(d c, d m, d} y, d k, d lc, d lm) spectral reflectivity of the grid points corresponding to R (lambda) is the spectral reflectance database RDB (for example, (From glossy paper).

FIG. 21 (B) shows the relationship between the ink area coverage f _c and the ink amount d _c which are used in the cell division model. Here, one kind of the ink amount in the range 0 to D _cmax of ink is also divided into three sections, the virtual used in the cell division model by non-linear curve which increases monotonically from 0 for each section to the 1 A typical ink coverage _fc is determined. For other inks, the ink coverages f _m and f _y are obtained in the same manner.

FIG. 21C shows the predicted spectral reflectance R _s (λ) when printing is performed with an arbitrary ink amount set (d _c , d _m ) in the center cell C5 of FIG. The calculation method is shown. The predicted spectral reflectance R _s (λ) when printing is performed with the ink amount set (d _c , d _m ) is given by the following equation (5).

Here, the ink coverages f _c and f _m in the equation (5) are values given by the graph of FIG. The spectral reflectances R (λ) ₁₁ , (λ) ₁₂ , (λ) ₂₁ , and (λ) ₂₂ corresponding to the four lattice points surrounding the cell C5 are acquired by referring to the spectral reflectance database RDB. Can do. As a result, all values constituting the right side of the equation (5) can be determined, and the predicted spectral reflection when printing is performed with an arbitrary ink amount set φ (d _c , d _m ) as the calculation result. The rate R _s (λ) can be calculated. By sequentially shifting the wavelength λ in the visible wavelength region, the predicted spectral reflectance R _s (λ) in the visible light region can be obtained. If the ink amount space is divided into a plurality of cells, the predicted spectral reflectance R _s (λ) can be calculated more accurately than when the ink amount space is not divided. As described above, when the RPM P3a2 predicts the predicted spectral reflectance R _s (λ) in response to the request of the ICM P3a1, the CCM P3a3 continues to use the predicted spectral reflectance R (λ). Predictions can be performed.

5. Modified example 5-1. Modification 1
In the above equation (2), the weighting factors w _{1 to} w ₅ of each light source are set to equal values, but the weighting factors w _{1 to} w ₅ may be set to be unequal. If the values of the weight counts w _{1 to} w ₅ are set large, the contribution ratio to the increase in the evaluation value E (φ) of the color differences ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , and ΔE _{F11 in} the corresponding light source is increased. be able to. Therefore, in order to minimize the evaluation value E (φ), the color differences ΔE _D50 , ΔE _D55 , ΔE _D65 , ΔE _A , and ΔE _{F11 of} the light source in which the values of the weighting factors w _{1 to} w ₅ are set to be large are particularly small values. According to the ink amount set φ that is optimized based on the evaluation value E (φ), the color differences ΔE _D50 and ΔE _D55 for the light source in which the values of the weighting factors w ₁ to w ₅ are set large , ΔE _D65 , ΔE _A , ΔE _F11 can be printed.

For example, the weight counts w _{1 to} w ₅ may be set by user designation. The user may designate the weighting factors w _{1 to} w ₅ according to the importance of the D50 light source, D55 light source, D65 light source, A light source, and F11 light source, respectively. For example, when the user wants to emphasize the color reproduction accuracy outdoors, the weighting factors w ₄ and w ₅ of the A light source and the F11 light source may be set small. Of course, a combination of weight counts w _{1 to} w ₅ preset in advance may be indirectly set by selecting an environment for observing the printed matter. Thereby, even when the user has no knowledge about the light source, it is possible to set appropriate weighting factors w _{1 to} w ₅ .

5-2. Modification 2
When the target TG is scanned using the scanner 30, the target color values in the absolute color space can be obtained by using the input ICC profiles SIP1 to SIP5 for the scanner 30. Therefore, when an image is input to the target TG using another image input device, an input ICC profile for the image input device may be used. For example, a target color value can be acquired by taking a photograph of the target TG using a digital still camera and converting the photograph image data using an input ICC profile. However, the digital still camera is affected by the ambient light during shooting, unlike the scanner 30 that blocks the ambient light during scanning and can always capture images with constant illumination light. Therefore, when the target color value of the target TG is acquired using a digital still camera, it is desirable to perform correction according to the environmental light at the time of shooting.

FIG. 22 shows print data generation processing according to this modification. Although the processing is almost the same as that of the above-described embodiment, in step S105, the reference color patch is imaged by the digital still camera, and the color data DD at that time is acquired. In this modification, a reference white plate is imaged as an example of the reference color patch. Further, the color data DD of the present modification is also acquired with RGB values (0 to 255 gradations) in the RGB color space, which is a device-dependent color space of the digital still camera. In the RGB color space, when R = G = B, an achromatic color is captured. Here, since the reference white plate is essentially achromatic, the RGB (R _w G _w B _w ) value when the reference white plate is imaged is R _w ≈G _w ≈B _w . However, a slight color is produced due to the influence of ambient light when the reference white plate is imaged, and R _w = G _w = B _w is not completely satisfied.

In step S140, the target TG is imaged by a digital still camera instead of the scanner 30 of the above-described embodiment, and color data DD (RGB values) is obtained. In step S141, the RGB value of the target TG is multiplied by the correction coefficient (255 / _Rw ), (255 / _Gw ), and (255 / _Bw ), respectively, to obtain the RGB value of the target TG. Correct. By doing in this way, correction | amendment which eliminates the color of the reference | standard white board by the environmental light at the time of imaging can be performed with respect to the RGB value of target TG. In step S142, the IPG P2c1 acquires five input ICC profiles SIP1 to SIP5 from the HDD 14 as in the previous embodiment. Here, input ICC profiles SIP1 to SIP5 of each light source prepared in advance for the digital still camera are acquired. In step S143, the corrected RGB values are converted by the input ICC profiles SIP1 to SIP5 as in the previous embodiment, so that the target color value for each light source can be acquired. As a result, the target color value that is finally converted can also be corrected so as to eliminate the color of the reference white plate due to the ambient light during imaging.

5-3. Modification 3
In the above-described modification, the correction is made uniformly based on the color of the reference white plate, but strictly speaking, the influence of environmental light on the entire color space can be grasped only by the color of the reference white plate. I can't. Further, the influence of the environmental light varies depending on the degree of the difference between the ambient light and the spectrum of each light source. Accordingly, not only the reference white plate but also a color chart composed of a plurality of reference color patches showing different colors may be imaged in step S105, and correction for each light source may be performed based on the result.

FIG. 23 schematically shows how correction is performed in this modification. Reference color measurement data (L ^* a ^* b ^* values) is prepared by measuring the reference color patch SCP under each light source. The reference colorimetric data is stored in advance in the HDD 14 and can be read and used as appropriate. When the reference color patches SCP (L ^* a ^* b ^* values) are inversely converted by the input ICC profiles SIP1 to SIP5, each reference color patch SCP is imaged with a digital still camera while irradiating each light source. The RGB values that will be obtained are obtained. On the other hand, in step S105, RGB values obtained by imaging a plurality of reference color patches SCP under the current ambient light are acquired by imaging a plurality of reference color patches SCP with a digital still camera. Then, the difference between the RGB value that would be obtained when each light source was irradiated and the RGB value captured under the current ambient light is calculated for each color patch, and a correction amount that eliminates this difference is calculated. A specified correction profile is created for each light source. In step S140, the target TG is imaged by the digital still camera to obtain RGB values, and in step S141, the RGB values are corrected by applying the correction profile of each light source to the RGB values of the target TG. If the RGB value can be corrected for each light source, in step S143, the corrected RGB value is converted by the input ICC profiles SIP1 to SIP5, and the target color value for each light source is acquired. In this way, stricter correction than in the previous modification can be realized, and a more accurate target color value can be acquired. Of course, different corrections may be performed for each light source based on the scan result of the standard white plate of the previous modification.

前記の（６）式の評価値Ｅ（φ）によれば、光源間の色変動の近似性も考慮したインク量セットφの最適化を行うことができる。 5-4. Modification 4
FIG. 24 schematically illustrates the evaluation value E (φ) according to the modification. In the figure, target light source color variation vectors V _t 1 to V _t 4 are calculated in the CIELAB space to connect the target color values of each light source in the order of D50 → D55, D55 → D65, D65 → A, and A → F11. Similarly, predicted inter-light source color variation vectors V _s 1 to V _s 4 are also calculated for predicted color values. Then, in each pair of color between the target light source variation vector V _t 1 to V _t 4 and the prediction source between color variation vector V _s 1 to V _s 4, the light source variability evaluation was indexing the size and direction of the similarity An index S (φ) is calculated. Then, the evaluation value E (φ) is defined as in the following equation (6).

According to the evaluation value E (φ) of the above equation (6), the ink amount set φ can be optimized in consideration of the approximation of the color variation between the light sources.

5-5. Modification 5
In addition, what is necessary is just to make it print with the same color as area | regions other than the frame F about the area | region corresponding to the frame F which is not selected in embodiment mentioned above. Of course, it is not necessary to request spectral reproducibility for the region corresponding to the unselected frame F, so that color conversion using a 3D-LUT is performed in the same manner as the region other than the frame F. That's fine. Furthermore, a pattern, characters, marks, or the like may be printed in a region other than the region corresponding to the frame F in which the target TG is designated. For example, characters indicating what the target TG is may be written near the frame F in which the target TG is designated. Furthermore, the light sources used for the evaluation are not limited to the five types used in the above-described embodiment, and other types of light sources may be used. Of course, the number of light sources used for the evaluation is not limited to five. For example, three types may be used to improve the reproducibility of the target TG with a narrower observation light source, or eight types of target TGs with more light sources. Reproducibility may be achieved.

2 is a block diagram illustrating a hardware configuration of a printing control apparatus. FIG. 2 is a block diagram illustrating a software configuration of a print control apparatus. FIG. 6 is a flowchart illustrating a flow of print data generation processing. It is a figure which shows an example of UI screen. It is a figure explaining an input ICC profile. It is a figure explaining a mode that a target color value is acquired. It is the figure which plotted the target color value. It is a figure explaining the calculation for calculating a color value based on a spectral reflectance. It is a figure which shows print data. It is a figure which shows an index table. 5 is a flowchart illustrating an overall flow of print control processing. It is a flowchart which shows the flow of 1D-LUT generation processing. It is a schematic diagram showing a flow of processing for optimizing the ink amount set. It is a schematic diagram which shows a mode that an ink amount set is optimized. It is a figure which shows 1D-LUT. 6 is a flowchart illustrating a flow of print control data generation processing. It is a figure which shows 3D-LUT. It is a schematic diagram which shows the printing system of a printer. It is a figure which shows a spectral reflectance database. It is a figure which shows a spectral Neugebauer model. It is a figure which shows a cell division | segmentation Yule-Nielsen spectroscopic Neugebauer model. The print data generation process concerning this modification is shown. It is a figure explaining the correction | amendment of the ambient light concerning another modification. It is a figure explaining the evaluation value concerning a modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Computer, 11 ... CPU, 12 ... RAM, 13 ... ROM, 14 ... HDD, 15 ... GIF, 16 ... VIF, 17 ... IIF, 18 ... Bus, P1 ... OS, P1a ... GDI, P1b ... Spooler, P2 ... APL, P2a ... UIM, P2b ... MCM, P2c ... PDG, P3 ... PDV, P3a1 ... ICM, P3a2 ... RPM, P3a3 ... CCM, P3a4 ... ECM, P3a5 ... LOM, P4 ... SDV, P5 ... DDV.

Claims (8)

A printing control device that designates a color material amount set that is a combination of the amount of use of the color materials to the printing device when performing printing by attaching a plurality of color materials to a recording medium in the printing device,
Input profile acquisition means for acquiring a plurality of input profiles that define the correspondence between color data obtained by image input in a predetermined image input device and color values under a plurality of light sources;
The color data obtained by inputting the target image with the image input device is converted by each of the plurality of input profiles, thereby obtaining the color value indicated by the target under a plurality of light sources as the target color value. A target color value acquisition means;
Based on the evaluation value that evaluates the closeness to the target color value under a plurality of light sources, predict the color material amount set indicating the color value that approximates the target color value under each light source on the recording medium, A print control apparatus comprising: a print control unit that causes the printing apparatus to execute printing based on the predicted color material amount set.   2. The target color value converted by the color data or a plurality of the input profiles is corrected according to ambient light when the target is imaged by the image input device. The printing control apparatus according to 1.   The ambient light when the target is imaged by the image input device is specified based on the color data obtained by inputting the reference color patch having a known color value by the image input device. The printing control apparatus according to claim 2, wherein the printing control apparatus is a printing control apparatus.   The print control apparatus according to claim 3, wherein the reference color patch indicates white.   The print control apparatus according to claim 1, wherein the image input apparatus is a scanner.   The print control apparatus according to claim 1, wherein the image input apparatus is a digital camera. A printing apparatus that performs printing by attaching a plurality of color materials to a recording medium and a color material amount set that is a combination of the usage amounts of the color materials are designated to the printing apparatus, and printing based on the color material amount set is performed. A printing system comprising a print control device to be executed,
The print control device includes:
Input profile acquisition means for acquiring a plurality of input profiles that define the correspondence between color data obtained by image input in a predetermined image input device and color values under a plurality of light sources;
The color data obtained by inputting the target image with the image input device is converted by each of the plurality of input profiles, thereby obtaining the color value indicated by the target under a plurality of light sources as the target color value. A target color value acquisition means;
Printing that predicts the color material amount set indicating on the recording medium the color value that approximates the target color value under each light source based on the evaluation value that evaluates the closeness to the target color value under a plurality of light sources Control means,
The printing apparatus includes:
A printing system comprising: a printing execution unit that executes printing based on the color material amount set predicted by the printing control unit. When printing is performed by attaching a plurality of color materials to a recording medium in a printing apparatus, a color material amount set that is a combination of the usage amounts of the color materials is designated to the printing apparatus, and based on the color material amount set A computer-readable print control program for causing a computer to execute a function of executing printing,
An input profile acquisition function for acquiring a plurality of input profiles defining a correspondence relationship between color data obtained by image input in a predetermined image input device and color values under a plurality of light sources;
The color data obtained by inputting the target image with the image input device is converted by each of the plurality of input profiles, thereby obtaining the color value indicated by the target under a plurality of light sources as the target color value. Target color value acquisition function,
Based on the evaluation value that evaluates the closeness to the target color value under a plurality of light sources, predict the color material amount set indicating the color value that approximates the target color value under each light source on the recording medium, A computer-readable print control program that causes a computer to execute a print control function that causes the printing apparatus to execute printing based on the predicted color material amount set.

Images