Selection system, method and computer program product for selecting ink amount setting

Abstract

The invention provides a selection system and method for selecting an ink amount setting, and a computer program product, which enable a user to select an appropriate ink amount setting according to a variety of uses and indicators. The selection system includes: a restriction condition designation unit that accepts designation of a restriction condition related to setting of an ink amount; an evaluation condition designation unit that accepts designation of an evaluation condition including an evaluation index related to the setting of the ink amount; an ink amount calculation unit that obtains a plurality of candidate ink amount settings by executing optimization processing under a restriction condition; an evaluation index calculation unit that calculates evaluation indexes for each of the plurality of candidate ink amount settings; and a notification unit that adds an evaluation index to each of the plurality of candidate ink amounts and presents the evaluation index to a user.

Description

Technical Field

[0001] The present disclosure relates to a selection system, method and computer program for selecting an ink volume setting. Background Art

[0002] Printing devices use a plurality of inks of different colors to print various printed materials. Since there is a considerable degree of freedom in setting the ink amount for reproducing the same color, various methods have been proposed to determine the ink amount setting for reproducing the target color. Patent document 1 discloses a technique for determining the ink amount setting based on the evaluation of metamerism characteristics. Metamerism characteristics refer to the characteristics that colors are viewed as almost the same even when viewing conditions such as illumination light are changed.

[0003] However, the above-mentioned prior art does not provide a means for the user to select an appropriate ink amount setting according to various uses and indices.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2006-159709 Summary of the invention

[0005] According to a first aspect of the present disclosure, there is provided a selection system for selecting ink quantity settings of a plurality of ink colors for reproducing a target color. The selection system comprises: a constraint condition designation unit that accepts the designation of a constraint condition related to the ink quantity setting; an evaluation condition designation unit that accepts the designation of an evaluation condition including an evaluation index related to the ink quantity setting; an ink quantity calculation unit that obtains a plurality of candidate ink quantity settings by performing an optimization process under the constraint condition; an evaluation index calculation unit that calculates the evaluation index for each of the plurality of candidate ink quantity settings; and a notification unit that adds the evaluation index to each of the plurality of candidate ink quantity settings and prompts the user.

[0006] According to a second aspect of the present disclosure, a method for selecting ink volume settings for a plurality of ink colors that reproduce a target color is provided. The method comprises the following steps: (a) a step of accepting the designation of a constraint condition related to the ink volume setting; (b) a step of accepting the designation of an evaluation condition including an evaluation index related to the ink volume setting; (c) a step of performing an optimization process under the constraint condition to obtain a plurality of candidate ink volume settings; (d) a step of calculating the evaluation index for each of the plurality of candidate ink volume settings; and (e) a step of adding the evaluation index to each of the plurality of candidate ink volume settings and presenting the result to a user.

[0007] According to a third aspect of the present disclosure, a computer program product is provided for selecting ink volume settings of a plurality of ink colors for reproducing a target color. The computer program product causes a computer to execute the following processing: (a) a process of accepting the designation of a constraint condition related to the ink volume setting; (b) a process of accepting the designation of an evaluation condition including an evaluation index related to the ink volume setting; (c) a process of obtaining a plurality of candidate ink volume settings by performing an optimization process under the constraint condition; (d) a process of calculating the evaluation index for each of the plurality of candidate ink volume settings; and (e) a process of adding the evaluation index to each of the plurality of candidate ink volume settings and presenting the result to a user. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is an explanatory diagram showing the structure of a printing system.

[0009] Figure 2 An explanatory diagram showing an example of the structure of an image processing device.

[0010] Figure 3 This is a flowchart showing the procedure of the selection process for setting the ink amount for reproducing the target color.

[0011] Figure 4 This is an explanatory diagram showing an example of a window for specifying a constraint condition.

[0012] Figure 5 This is an explanatory diagram showing an example of a window for designating evaluation conditions.

[0013] Figure 6 It is an explanatory diagram showing an example of a window for designating optimization processing conditions.

[0014] Figure 7 This is an explanatory diagram showing an ink amount setting table used for setting the initial value of the ink amount setting.

[0015] Figure 8 It is a flowchart showing the processing procedure of step S40.

[0016] Fig. 9 This is an explanatory diagram showing an example of a window for notifying a plurality of ink amount setting candidates. DETAILED DESCRIPTION

[0017] Figure 1 1 is an explanatory diagram showing the configuration of a printing system 500 according to an embodiment. The printing system 500 includes an image processing device 100, an input device 200, a display device 300, and a printing device 400. However, the printing device 400 can be omitted. The image processing device 100 functions as a "selection system" of the present disclosure.

[0018] The image processing device 100 includes a processor 101, a memory 102, an input / output interface 103, and an internal bus 104. The processor 101, the memory 102, and the input / output interface 103 are connected via the internal bus 104 in a bidirectionally communicable manner. The memory 102 includes a volatile memory and a non-volatile memory such as a hard disk and an SSD (Solid State Drive), and the volatile memory includes a main memory and a video memory. The input device 200, the display device 300, and the printing device 400 are connected to the input / output interface 103 of the image processing device 100 through wired communication or wireless communication. The input device 200 is, for example, a keyboard and a mouse, and the display device 300 is, for example, a liquid crystal display. The input device 200 and the display device 300 may also be integrated into a touch panel. The printing device 400 is, for example, an inkjet printer, and prints an image on a printing medium PM using a plurality of types of inks.

[0019] As described below, the image processing apparatus 100 executes processing for obtaining candidate ink amount settings for reproducing a target color and presenting them to a user in order to print a specific target color such as a logo or a corporate standard color by the printing apparatus 400 .

[0020] Figure 2 1 is an explanatory diagram showing an example of the structure of the image processing device 100. The image processing device 100 includes a constraint condition specifying unit 110, an evaluation condition specifying unit 120, an ink amount calculating unit 130, an evaluation index calculating unit 140, a notifying unit 150, and a color substitution table creating unit 160. The functions of each of these units are implemented in software by the processor 101 executing a computer program PG pre-stored in the memory 102. However, part of the functions of each unit may be implemented by a hardware circuit.

[0021] The constraint condition designation unit 110 receives the designation of the constraint condition CC and the optimization processing condition OC related to the optimization process for obtaining the candidate ink amount setting for reproducing the target color TC. The evaluation condition designation unit 120 receives the designation of the evaluation condition EC. The evaluation condition EC includes the evaluation index EI and the target color TC. Examples of the constraint condition CC, the optimization processing condition OC and the evaluation condition EC will be described below. The ink amount calculation unit 130 performs the optimization process under the constraint condition CC, thereby obtaining a plurality of candidate ink amount settings ISC for one target color TC. In the present embodiment, the ink amount calculation unit 130 uses a color prediction model 132 that predicts the spectral reflectance of the printed matter reproduced by the ink amount setting using a value according to the ink amount setting. The color prediction model 132 can be, for example, a color prediction model based on the well-known spectral Neugebauer model or a regression model of a multi-dimensional output composed of a neural network. As a color prediction model based on the spectral Neugebauer model, a printing model described in Japanese Patent Publication No. 2006-334945 disclosed by the present applicant can be used. The evaluation index calculation unit 140 calculates the evaluation index EI for each of the plurality of candidate ink amount settings ISC. The notification unit 150 adds the evaluation index EI to each of the plurality of candidate ink amount settings ISC and presents the result to the user.

[0022] The color substitution table creation unit 160 creates a color substitution table CRT for the printing device 400 using the ink amount setting IAS selected by the user from a plurality of candidate ink amount settings ISC. The color substitution table CRT is a lookup table used in color conversion from an input color space or a device-independent color space to an output color space for the printing device 400. The input color space is, for example, an RGB color space or a CMYK color space. The device-independent color space is, for example, a CIE-L*a*b* color space or a CIE-XYZ color space. As the output color space for the printing device 400, various ink color spaces such as a CMYK color space and a CMYKLkLLk color space can be used. The "CMYKLkLLk color space" is a color space composed of six ink color components, namely, C (cyan), M (magenta), Y (yellow), K (black), Lk (gray), and LLk (light gray). When the target color TC is printed using the printing device 400, the color conversion from the input color space or the device-independent color space to the output color space for the printing device 400 is performed using the color substitution table CRT. The color substitution table creation unit 160 may be omitted.

[0023] Figure 3 1 is a flowchart showing the procedure of the process of selecting the ink amount setting for reproducing the target color. In step S10, the constraint condition designation unit 110 receives the designation of the constraint condition CC.

[0024] Figure 4 1 is an explanatory diagram showing an example of a window W1 for specifying a constraint condition CC. In this example, the constraint condition CC includes the following items.

[0025] (1) Whether each ink that can be used by the printing device 400 can be used.

[0026] (2) Duty cycle restrictions on the inks that can be used.

[0027] (3) Duty cycle limitation of secondary colors.

[0028] (4) Duty cycle limit of total ink volume TIA.

[0029] The duty cycle is the ratio of the amount of ink, and a duty cycle of 100% means an amount equivalent to the full spraying of the ink. The duty cycle of the secondary color is the sum of the duty cycles of the two types of inks that reproduce the secondary color. The lower limit of the duty cycle is set in consideration of the granularity. For example, when light gray can be reproduced using either light gray ink or black ink, the granularity decreases when the black ink is used for reproduction. Therefore, in order to give priority to the use of light gray, it is preferred to set a lower limit of the duty cycle for the light gray. However, the lower limit of the duty cycle may be omitted. In addition, the duty cycle restriction of the secondary color may also be omitted. The user can arbitrarily specify these constraints CC according to the target color TC. In Figure 4 In the example of , it is specified that cyan ink cannot be used, but the other five types of ink can be used. The ink amount calculation unit 130 searches for ink amount settings that are a combination of ink amounts that satisfy the constraint condition CC.

[0030] In step S20 , the evaluation condition designation unit 120 receives the designation of the evaluation condition EC.

[0031] Figure 5 2 is an explanatory diagram showing an example of the window W2 for designating the evaluation condition EC. In this example, the evaluation condition EC includes the following items.

[0032] (1) Target color TC reproduced by setting the candidate ink amounts.

[0033] (2) Evaluation index EI to be calculated for the candidate ink amount setting.

[0034] exist Figure 5In the example of , as data related to the target color TC, data "Gray1.csv" indicating the spectral reflectance of the target color TC is specified. The spectral reflectance is obtained by spectrally measuring the color bar of the target color TC. In addition, the target color TC may be specified using the color measurement value Lab of the CIE-L*a*b* color space and the tristimulus value XYZ of the CIE-XYZ color space instead of the spectral reflectance. In addition, the target color TC may be specified using a color name associated with the spectral reflectance. When the color name is used, the ink amount calculation unit 130 performs the following processing, i.e., the candidate ink amount setting is obtained using the spectral reflectance defined in a manner associated with the specified color name.

[0035] As the evaluation index EI, for example, one or more of the following can be used.

[0036] (a) Color rendering index CRI.

[0037] (b) Color difference evaluation index CDI.

[0038] (c) Light source dependence index SDI.

[0039] (d) Total ink amount TIA.

[0040] (e) Granularity index GI.

[0041] The color reproducibility index CRI is the color difference between the color reproduced by the candidate ink amount setting, that is, the candidate color and the target color TC. The colorimetric value Lab of the candidate color can be obtained by using the color prediction model 132 and predicting the spectral reflectance according to the candidate ink amount setting, and using the spectral reflectance to calculate the tristimulus value XYZ under the observation condition using a specific light source, and converting the tristimulus value XYZ into the colorimetric value Lab. The colorimetric value Lab of the target color TC can be obtained by using the spectral reflectance of the target color TC to calculate the tristimulus value XYZ under the observation condition using a specific light source, and converting the tristimulus value XYZ into the colorimetric value Lab. The color reproducibility index CRI is calculated by applying these two colorimetric values ​​Lab to the color difference formula of CIE DE2000, etc. In the present embodiment, as the specific light source used in the calculation of the color reproducibility index CRI, D50, which is the standard light source of CIE, is used. However, other light sources such as D65 can also be used. Since the color reproducibility index CRI is the color difference between the candidate color and the target color TC, the smaller the better.

[0042] The color difference evaluation index CDI represents a representative value of the color difference between the candidate color reproduced by the candidate ink amount setting and the target color TC under multiple light sources. Figure 5In the example, as the light source for calculating the color difference evaluation index CDI, five light sources other than F12 are selected from the six standard light sources of D50, D65, A, F8, F10, and F12. At this time, the color difference evaluation index CDI is calculated as the representative value of the five color differences obtained using the five light sources respectively. As the representative value, it is preferable to use the average value. However, the maximum value, the central value, etc. can also be used instead of the average value. In addition, it can also be set that in the case of an observation location of the printed matter, the spectral distribution actually measured at the observation location can be specified as the light source. Since the color difference evaluation index CDI is a representative value of the color difference between the candidate color and the target color TC under multiple light sources, the smaller the better.

[0043] The light source dependency index SDI represents the difference between the appearance of the candidate color reproduced by the candidate ink amount setting under the reference light source and the appearance under the reference light source. As the reference light source, one of a plurality of light sources can be selected, and as the reference light source, more than one light source can be selected. Figure 5 In the example, D50 is selected as the reference light source, and four standard light sources, namely D65, A, F8, and F10, are selected as the reference light source. At this time, the light source dependence index SDI is calculated as a representative value of four color differences calculated based on the colorimetric value Lab of the candidate color under the reference light source and the colorimetric value Lab under each reference light source. As the representative value, it is preferable to use the average value. However, a maximum value, a central value, etc. may be used instead of the average value. In addition, it may be set so that, in the case where an observation location of a printed matter is assumed, the spectral distribution actually measured at the observation location can be designated as the reference light source. Since the light source dependence index SDI represents the difference between the appearance of the candidate color under the reference light source and the appearance under the reference light source, the smaller the better.

[0044] The total ink amount TIA is the total value of the ink amounts set for the candidate ink amounts. However, when the unit prices of the inks of the respective colors are different, weighting may be applied to each ink color. In addition, the ink amount of each ink color may be used as an evaluation index instead of the total ink amount TIA. Basically, the more ink amount, the higher the cost, so the less ink amount, the better.

[0045] The granularity index GI is an index indicating the degree of granularity, i.e., noise, felt by an observer when visually checking a printed material. As the granularity index GI, for example, the granularity index GI described in Japanese Patent No. 4388553 of the present applicant can be used. The granularity index GI is calculated as an index that simulates the recording state of points in a virtual color patch reproduced by setting the candidate ink amount and evaluates the spatial frequency of the simulation result. Specifically, the granularity index GI is calculated, for example, according to the following formula.

[0046] Number 1

[0047]

[0048] Here, a L is the brightness correction term, WS(u) is the Wiener spectrum of the image, VTF is the visual spatial frequency characteristic, and u is the spatial frequency. Although the one-dimensional spatial frequency u is used in the formula (q1), the formula using the two-dimensional spatial frequencies u and v is the same.

[0049] Instead of the above formula (q1), a granularity prediction model for calculating the granularity index GI according to the ink amount setting may be prepared by machine learning, and the granularity prediction model may be used to obtain the granularity index GI according to the candidate ink amount setting. Figure 5 In the example of , it is specified to use the granularity prediction model "Ryujo.model" created by machine learning. The smaller the granularity index GI, the better.

[0050] As an item of evaluation condition EC, it can be omitted Figure 5 Some of the items shown are included, and items other than these items may be added. However, it is preferred that the evaluation condition EC at least includes the evaluation index EI.

[0051] In step S30 , the constraint condition specifying unit 110 receives the specification of the optimization processing condition OC.

[0052] Figure 6 1 is an explanatory diagram showing an example of a window W3 for designating optimization processing conditions OC. In this example, the optimization processing conditions OC include the following items.

[0053] (1) An initial ink amount as an initial value for ink amount setting.

[0054] (2) Objective function TF and target value TV in the optimization process of searching for candidate ink amount settings.

[0055] exist Figure 6 In the example in , it is specified that the initial ink volume is automatically selected. Figure 7 1 is an explanatory diagram showing an ink amount setting table IST used for setting the initial value of the ink amount setting. The ink amount setting table IST is a group of ink amount settings sampled at equal intervals in the ink amount space CMYKLkLLk. Figure 7 In the example, since the sampling is performed at equal intervals of 10%, the number of ink volume settings is 11. 6 The ink amount calculation unit 130 automatically selects an initial value that satisfies the constraint condition CC from the ink amount setting table IST, and performs a search for candidate ink amount settings.

[0056] As the objective function TF of the optimization process, the color reproducibility index CRI is selected. As the objective function TF, other indicators may be used, and in addition, an integrated indicator including multiple indicators may be used. However, it is preferred that the objective function TF is set as a function including the color difference between the color reproduced by the candidate ink amount setting and the target color TC. The target value TV of the objective function TF can be arbitrarily set by the user according to the type of the objective function TF. In addition, it may be set that the user does not set the optimization process condition OC, but uses a pre-set condition.

[0057] exist Figure 3 In step S40 , the ink amount calculation unit 130 obtains a plurality of candidate ink amount settings ISC capable of reproducing the target color TC through optimization processing.

[0058] Figure 8 FIG. 4 is a flowchart showing the processing sequence of step S40. In step S41, the ink amount calculation unit 130 determines the initial value of the ink amount setting. In step S42, the ink amount calculation unit 130 calculates the initial value of the ink amount by Figure 4 The optimization process is performed under the constraint CC set in step S42 to search for a candidate ink amount setting ISC. However, when step S42 is performed for the first time, the initial value determined in step S41 is used as the candidate ink amount setting ISC.

[0059] In step S43, the ink amount calculation unit 130 calculates the target function TF of the candidate ink amount setting ISC using the color prediction model 132. As the target function TF, Figure 6 The color reproducibility index CRI was selected in the optimized processing conditions OC.

[0060] In step S44, the ink amount calculation unit 130 determines whether the candidate ink amount setting ISC has been fully optimized. Specifically, when the objective function TF becomes less than the preset target value TV, it is determined that it has been fully optimized. On the other hand, when the objective function TF is greater than the target value TV, it is determined that it has not been fully optimized. In the case of being fully optimized, the ink amount calculation unit 130 selects a most appropriate candidate ink amount setting ISC in step S46 and proceeds to step S47 described below.

[0061] On the other hand, if the optimization is not sufficient, the process proceeds to step S45, and the ink amount calculation unit 130 determines whether the end condition of the optimization process has been satisfied. Specifically, if the number of searches or the search time reaches the upper limit, the end condition is determined to be satisfied, and if the number of searches or the search time does not reach the upper limit, the end condition is determined to be not satisfied. If the end condition is not satisfied, the process returns to step S42, and the process after step S42 is executed again. If the end condition is satisfied, the process proceeds to step S47.

[0062] In step S47, the ink amount calculation unit 130 determines whether to execute the process of obtaining other candidate ink amount setting ISCs. In the present embodiment, since a plurality of candidate ink amount setting ISCs are obtained for one target color TC, when the number of candidate ink amount setting ISCs does not reach the preset target number, it is determined that the process of obtaining other candidate ink amount setting ISCs is to be executed. For example, when the method of assigning the initial value of the ink amount setting is changed and other candidate ink amount setting ISCs are obtained, the number of cycles of steps S41 to S48 is equal to the number of initial values ​​of the ink amount setting.

[0063] When executing the process of obtaining other candidate ink amount setting ISC, the conditions of the optimization process are changed in step S48. Specifically, for example, by executing one or more of the following changes, the next candidate ink amount setting ISC can be searched.

[0064] (1) Change the initial value of the ink volume setting.

[0065] (2) Change part of the constraint CC.

[0066] (3) Change the objective function TF.

[0067] Although these changes can be made by the user, it is preferable that the ink amount calculation unit 130 automatically makes the changes. For example, when a constraint condition such as 0<K<100 is imposed as a duty ratio limit for K ink, a plurality of changes such as (i) 0<K<50, (ii) 0<K<80, and (iii) 10<K<100 may be set as internal processing of the ink amount calculation unit 130 and used as changes to the constraint condition CC.

[0068] After step S48, the process returns to step S41 and the processes of steps S41 to S47 are executed again. In this way, by changing a part of the conditions of the optimization process and executing the optimization process, a plurality of candidate ink amount setting ISCs can be obtained. When the process of step S40 is finished, the process proceeds to step S47. Figure 3 Step S50.

[0069] In step S50, the evaluation index calculation unit 140 calculates the evaluation index EI for each candidate ink amount setting ISC. Figure 5 In the example of FIG. 1 , since the color reproducibility index CRI, the color difference evaluation index CDI, the light source dependency index SDI, the total ink amount TIA, and the granularity index GI are selected as the evaluation index EI, these evaluation indexes EI are calculated for each candidate ink amount setting ISC. The value of the evaluation index EI is supplied to the notification unit 150 together with the candidate ink amount setting ISC. In step S60, the notification unit 150 presents the plurality of candidate ink amount setting ISCs and the evaluation index EI to the user.

[0070] Fig. 9 This is an explanatory diagram showing a window W4 for notifying a plurality of candidate ink volume settings ISC. Here, the plurality of candidate ink volume settings ISC obtained for one target color TC are displayed with the evaluation index EI added to each of them. The number of candidate ink volume settings ISC displayed is set to 20, but Fig. 9 Only three candidate ink volume settings ISC1 to ISC3 are illustrated. In addition, in this example, a filter is used to display candidate ink volume settings with a total ink volume TIA less than 150. However, filters using other indicators can also be applied. In this window W3, any one of the five items CRI, CDI, SDI, TIA, and GI of the evaluation index EI can also be used to perform sorting, that is, re-sorting. Fig. 9 In the example, the candidate ink volume settings ISC are sorted in ascending order of the color reproducibility index CRI. In addition, multiple items can be used in a complex manner to implement the sorting. The user can select a preferred candidate ink volume setting ISC corresponding to the application from among multiple candidate ink volume settings ISC. That is, the user can select an appropriate candidate ink volume setting according to various applications, such as applications that want to prioritize absolute color reproducibility, applications that want to provide the same appearance under various light sources, and applications that want to suppress the amount of ink. Fig. 9 In the example of FIG. 5 , the second candidate ink amount setting ISC2 is selected as the ink amount setting suitable for reproduction of the target color TC.

[0071] exist Figure 3 In step S70 , the color substitution table creation unit 160 receives the one ink amount setting IAS selected in step S60 . In addition, the target color TC is also input to the color substitution table creation unit 160 .

[0072] In step S80, it is determined whether the processing of steps S10 to S70 has been completed. In the case where there are multiple target colors TC, if the processing of steps S10 to S70 has been completed for all target colors TC, it is determined that the processing has been completed. In the case where the processing has not been completed, the processing of steps S10 to S70 is performed again. In step S90, the color substitution table creation unit 160 uses the ink amount setting IAS and the target color TC to create a color substitution table CRT for the printing device 400. However, step S90 may be omitted.

[0073] As described above, in the present embodiment, a plurality of candidate ink volume settings ISC are obtained for one target color TC using the constraint conditions CC and the evaluation conditions EC specified by the user, and the evaluation index EI for each candidate ink volume setting ISC is added and presented to the user, so that the user can easily select an ink volume setting suitable for the reproduction of the target color TC. In addition, in the present embodiment, the ink volume setting suitable for a partial area or a color gamut of a printed material can be freely selected, so that content production reflecting the user's intention can be performed. Specifically, for example, content production reflecting the following intention can be performed, that is, the target color of a wide background uses an ink volume setting that emphasizes ink cost, and the special target color such as a corporate standard color uses an ink volume setting that emphasizes color reproducibility.

[0074] Other ways:

[0075] The present disclosure is not limited to the above-mentioned embodiments, and can be implemented in various ways without departing from the scope of the present disclosure. For example, the present disclosure can also be implemented in the following ways. In order to solve part or all of the problems of the present disclosure, or to achieve part or all of the effects of the present disclosure, the technical features in the above-mentioned embodiments corresponding to the technical features in the various modes described below can be appropriately replaced or combined. In addition, if the technical feature is not described as a necessary feature in this specification, it can be appropriately deleted.

[0076] (1) According to a first aspect of the present disclosure, there is provided a selection system for selecting ink quantity settings of a plurality of ink colors for reproducing a target color. The selection system comprises: a constraint condition specifying unit that accepts the specification of a constraint condition related to the ink quantity setting; an evaluation condition specifying unit that accepts the specification of an evaluation condition including an evaluation index related to the ink quantity setting; an ink quantity calculation unit that obtains a plurality of candidate ink quantity settings by performing an optimization process under the constraint condition; an evaluation index calculation unit that calculates the evaluation index for each of the plurality of candidate ink quantity settings; and a notification unit that adds the evaluation index to each of the plurality of candidate ink quantity settings and presents the result to a user.

[0077] According to this selection system, the user can easily select an ink amount setting suitable for reproduction of a target color from among a plurality of candidate ink amount settings.

[0078] (2) In the above selection system, the constraint condition may include at least one of whether each ink color can be used, a duty cycle limit for each ink color, and a duty cycle limit for a total amount of ink.

[0079] According to this selection system, it is possible to set constraints on which ink color is used and to what extent.

[0080] (3) In the above-mentioned selection system, the following method can be adopted, that is, the evaluation index includes at least one of the following items: a color reproducibility index, which represents the color difference between the candidate color represented by the candidate ink amount setting and the target color under a specific light source; a color difference evaluation index, which represents a representative value of the color difference between the candidate color and the target color under multiple light sources; a light source dependence index, which represents the difference between the appearance of the candidate color under a reference light source and the appearance under a reference light source; the total ink amount of the candidate ink amount setting; and a granularity index of the printed matter reproduced by the candidate ink amount setting.

[0081] According to this selection system, it is possible to provide index values ​​related to various evaluation indexes together with ink amount settings.

[0082] (4) In the above-mentioned selection system, the following method can be adopted, that is, the ink amount calculation unit obtains the multiple candidate ink amount settings by executing at least one of (i) changing the initial value of the ink amount setting, (ii) changing the constraint condition, and (iii) changing the objective function in the optimization process.

[0083] According to this selection system, a plurality of ink amount setting candidates can be obtained under various conditions.

[0084] (5) According to a second aspect of the present disclosure, a method for selecting ink volume settings for a plurality of ink colors that reproduce a target color is provided. The method comprises the following steps, namely, (a) a step of accepting the designation of a constraint condition related to the ink volume setting; (b) a step of accepting the designation of an evaluation condition including an evaluation index related to the ink volume setting; (c) a step of performing an optimization process under the constraint condition to obtain a plurality of candidate ink volume settings; (d) a step of calculating the evaluation index for each of the plurality of candidate ink volume settings; and (e) a step of adding the evaluation index to each of the plurality of candidate ink volume settings and presenting the evaluation index to a user.

[0085] (6) According to a third aspect of the present disclosure, there is provided a computer program for selecting ink quantity settings for a plurality of ink colors that reproduce a target color. The computer program causes a computer to execute the following processing: (a) a process of accepting the designation of a constraint condition related to the ink quantity setting; (b) a process of accepting the designation of an evaluation condition including an evaluation index related to the ink quantity setting; (c) a process of obtaining a plurality of candidate ink quantity settings by performing an optimization process under the constraint condition; (d) a process of calculating the evaluation index for each of the plurality of candidate ink quantity settings; and (e) a process of adding the evaluation index to each of the plurality of candidate ink quantity settings and presenting the result to a user.

[0086] The present disclosure can be implemented in various forms other than the image processing apparatus, the printing system, and the computer program. For example, the present disclosure can be implemented in the form of an image processing method, a non-transitory storage medium having the computer program recorded thereon, and the like.

[0087] Explanation of symbols

[0088] 100…image processing device; 101…processor; 102…memory; 103…input / output interface; 104…internal bus; 110…constraint condition specifying unit; 120…evaluation condition specifying unit; 130…ink quantity calculation unit; 132…color prediction model; 140…evaluation index calculation unit; 150…notification unit; 160…color substitution table preparation unit; 200…input device; 300…display device; 400…printing device; 500…printing system.

Claims

1. A selection system for selecting ink amount settings of a plurality of ink colors for reproducing a target color, The selection system comprises: a constraint condition designation unit that receives a designation of a constraint condition related to the ink amount setting; an evaluation condition designation unit that receives designation of evaluation conditions including an evaluation index related to the ink amount setting; an ink amount calculation unit that obtains a plurality of candidate ink amount settings by performing an optimization process under the constraints; an evaluation index calculation unit that calculates the evaluation index for each of the plurality of candidate ink amount settings; The notification unit adds the evaluation index to each of the plurality of candidate ink amount settings and presents the evaluation index to a user.

2. The selection system of claim 1, wherein: The constraint condition includes at least one of whether each of the ink colors can be used, a duty cycle limit for each of the ink colors, and a duty cycle limit for a total amount of ink.

3. The selection system of claim 1, wherein: The evaluation index includes at least one of the following: a color reproducibility index, which represents the color difference between the candidate color represented by the candidate ink amount setting and the target color under a specific light source; a color difference evaluation index, which represents a representative value of the color difference between the candidate color and the target color under multiple light sources; a light source dependence index, which represents the difference between the appearance of the candidate color under a reference light source and the appearance under a reference light source; the total ink amount of the candidate ink amount setting; and a granularity index of a printed material reproduced by the candidate ink amount setting.

4. The selection system of claim 1, wherein: The ink amount calculation unit obtains the plurality of candidate ink amount settings by performing at least one of the following in the optimization process: (i) Change the initial value of ink volume setting; (ii) changing the constraints; as well as (iii) Change the objective function.

5. A method for selecting ink amounts of a plurality of ink colors for reproducing a target color, comprising the following steps: (a) a step of accepting designation of a constraint condition related to the ink amount setting; (b) a step of accepting designation of evaluation conditions including evaluation indicators related to the ink amount setting; (c) a step of performing an optimization process under the constraints to obtain a plurality of candidate ink amount settings; (d) a step of calculating the evaluation index for each of the plurality of candidate ink amount settings; (e) A step of adding the evaluation index to each of the plurality of candidate ink amount settings and presenting the evaluation index to a user.

6. A computer program product for selecting ink quantity settings of a plurality of ink colors for reproducing a target color, and causing a computer to execute the following processing: (a) receiving a designation of a constraint condition related to the ink amount setting; (b) receiving a designation of evaluation conditions including an evaluation index related to the ink amount setting; (c) a process of obtaining a plurality of candidate ink amount settings by performing an optimization process under the constraints; (d) calculating the evaluation index for each of the plurality of candidate ink amount settings; (e) A process of adding the evaluation index to each of the plurality of candidate ink amount settings and presenting the evaluation index to the user.

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