Selection system for selecting ink amount set, method, and computer program

Abstract

To provide a technique capable of selecting an appropriate ink amount set by a user in accordance with various applications and an index.SOLUTION: A selection system comprises: a restriction condition designation part that receives a designation of a restriction condition in regard to an ink amount set; an evaluation condition designation part that receives a designation of an evaluation condition containing an evaluation index in regard to an ink amount set; an ink amount calculation part that calculates a plurality of regard to ink amount set candidates by executing an optimum processing under the restriction condition; an evaluation index calculation part that calculates the evaluation index against the plurality of ink amount set candidates; and a notification part that adds the evaluation index to the plurality of ink amount set candidates, and provides them to a user.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a selection system, method, and computer program for selecting an ink quantity set. [Background technology]

[0002] A printing device prints various printed materials using a plurality of inks of different colors. Since there is a considerable degree of freedom in the ink amount set for reproducing the same color, various methods have been proposed for determining the ink amount set for reproducing the target color. Patent Document 1 discloses a technology for determining an ink amount set after evaluating metamerism characteristics. Metamerism characteristics refer to the characteristic that a color appears almost the same even if the observation conditions such as the illumination light are changed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-159709 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional techniques do not provide a means for the user to select an appropriate ink amount set in accordance with various applications and indexes. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a selection system used to select an ink quantity set of a plurality of ink colors for reproducing a target color, the selection system comprising: a constraint condition specification unit that accepts specification of constraint conditions related to the ink quantity set, an evaluation condition specification unit that accepts specification of evaluation conditions including an evaluation index related to the ink quantity set, an ink quantity calculation unit that obtains a plurality of ink quantity set candidates by executing an optimization process under the constraint conditions, an evaluation index calculation unit that calculates the evaluation index for each of the plurality of ink quantity set candidates, and a notification unit that adds the evaluation index to each of the plurality of ink quantity set candidates and presents them to a user.

[0006] According to a second aspect of the present disclosure, there is provided a method for selecting an ink quantity set of a plurality of ink colors for reproducing a target color, the method comprising the steps of: (a) accepting a designation of constraint conditions for the ink quantity set; (b) accepting a designation of evaluation conditions including an evaluation index for the ink quantity set; (c) obtaining a plurality of ink quantity set candidates by performing an optimization process under the constraint conditions; (d) calculating the evaluation index for each of the plurality of ink quantity set candidates; and (e) adding the evaluation index to each of the plurality of ink quantity set candidates and presenting them to a user.

[0007] According to a third aspect of the present disclosure, there is provided a computer program for selecting an ink quantity set of multiple ink colors for reproducing a target color, the computer program causing a computer to execute the following processes: (a) accepting specification of constraint conditions related to the ink quantity set, (b) accepting specification of evaluation conditions including evaluation indexes related to the ink quantity set, (c) executing an optimization process under the constraint conditions to obtain multiple ink quantity set candidates, (d) calculating the evaluation indexes for each of the multiple ink quantity set candidates, and (e) adding the evaluation indexes to each of the multiple ink quantity set candidates and presenting them to a user. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a printing system. [Diagram 2] FIG. 1 is an explanatory diagram showing an example of the configuration of an image processing apparatus. [Diagram 3] 10 is a flowchart showing the procedure for selecting an ink amount set that reproduces a target color. [Figure 4] FIG. 13 is an explanatory diagram showing an example of a window for specifying constraint conditions. [Diagram 5] FIG. 13 is an explanatory diagram showing an example of a window for specifying evaluation conditions. [Figure 6] FIG. 13 is an explanatory diagram showing an example of a window for specifying optimization processing conditions. [Figure 7] FIG. 4 is an explanatory diagram showing an ink amount set table used to set the initial value of the ink amount set. [Figure 8] 11 is a flowchart showing the processing procedure of step S40. [Figure 9] FIG. 13 is an explanatory diagram showing an example of a window for notifying a plurality of ink amount set candidates. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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 is optional. The image processing device 100 functions as a "selection system" in the present disclosure.

[0010] 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 to enable bidirectional communication. The memory 102 includes a volatile memory including a main memory and a video memory, and a non-volatile memory such as a hard disk and an SSD (Solid State Drive). 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 by wired communication or wireless communication. The input device 200 is, for example, a keyboard or a mouse, and the display device 300 is, for example, a liquid crystal display. The input device 200 and the display device 300 may be integrated as a touch panel. The printing device 400 is, for example, an inkjet printer, and prints an image on a printing medium PM using multiple types of ink.

[0011] As described below, in order to print a specific target color such as a logo or corporate color with the printing device 400, the image processing device 100 executes a process of determining candidate ink amount sets that reproduce the target color and presenting them to the user.

[0012] 2 is an explanatory diagram showing an example of the configuration of the image processing device 100. The image processing device 100 comprises a constraint condition specification unit 110, an evaluation condition specification unit 120, an ink amount calculation unit 130, an evaluation index calculation unit 140, a notification unit 150, and a color replacement table creation unit 160. The functions of each of these units are realized in software by the processor 101 executing a computer program PG stored in advance in the memory 102. However, some of the functions of each unit may also be realized by hardware circuits.

[0013] The constraint condition specification unit 110 accepts specification of constraint conditions CC and optimization processing conditions OC related to the optimization process for finding ink amount set candidates that reproduce a target color TC. The evaluation condition specification unit 120 accepts specification of evaluation conditions EC. The evaluation conditions EC include an evaluation index EI and a target color TC. Examples of the constraint conditions CC, optimization processing conditions OC, and evaluation conditions EC will be described later. The ink amount calculation unit 130 executes an optimization process under the constraint conditions CC to find multiple ink amount set candidates ISC for one target color TC. In this embodiment, the ink amount calculation unit 130 uses a color prediction model 132 that predicts the spectral reflectance of a printed matter reproduced with an ink amount set from the value of the ink amount set. The color prediction model 132 can be configured, for example, as a color prediction model based on a known spectral Neugebauer model, or a regression model of a multidimensional output configured by a neural network. As a color prediction model based on the spectral Neugebauer model, the printing model disclosed by the present applicant in JP 2006-334945 A can be used. The evaluation index calculation unit 140 calculates an evaluation index EI for each of the multiple ink amount set candidates ISC. The notification unit 150 adds an evaluation index EI to each of the multiple ink amount set candidates ISC and presents them to the user.

[0014] The color replacement table creation unit 160 creates a color replacement table CRT for the printing device 400 using an ink amount set IAS selected by the user from among a plurality of ink amount set candidates ISC. The color replacement table CRT is a lookup table used for 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, the RGB color space or the CMYK color space. The device-independent color space is, for example, the CIE-L * a * b *color space or CIE-XYZ color space. As the output color space for the printing device 400, various ink color spaces such as the CMYK color space or the CMYKLkLLk color space can be used. The "CMYKLkLLk color space" is a color space consisting of six ink color components: C (cyan), M (magenta), Y (yellow), K (black), Lk (gray), and LLk (light gray). When printing the target color TC using the printing device 400, a color conversion is performed from the input color space or the device-independent color space to the output color space for the printing device 400 using a color conversion table CRT. The color conversion table creation unit 160 can be omitted.

[0015] 3 is a flow chart showing the procedure for the process of selecting an ink amount set that reproduces a target color.In step S10, the constraint condition specification unit 110 accepts the specification of a constraint condition CC.

[0016] 4 is an explanatory diagram showing an example of a window W1 for specifying the constraints CC. In this example, the constraints CC include the following items: (1) Whether or not each ink that can be used by the printing device 400 can be used. (2) Duty limits of ink that can be used. (3) Duty limit for secondary colors. (4) Total ink volume TIA duty limit.

[0017] The duty is a ratio of the amount of ink, and a duty of 100% means an amount equivalent to a solid ink application. The duty of a secondary color is the sum of the duties of the two types of ink that reproduce the secondary color. The lower limit of the duty is set in consideration of graininess. For example, when a light gray color can be reproduced using either light gray ink or black ink, reproducing it with black ink reduces graininess, so it is preferable to set the lower limit of the duty for light gray in order to use light gray preferentially. However, the lower limit of the duty may be omitted. Also, the duty limit of the secondary color may be omitted. The user can arbitrarily specify these constraint conditions CC according to the target color TC. In the example of FIG. 4, it is specified that cyan ink cannot be used, and the other five types of ink can be used. The ink amount calculation unit 130 searches for an ink amount set that is a combination of ink amounts that satisfies this constraint condition CC.

[0018] In step S20, the evaluation condition designation unit 120 accepts the designation of evaluation conditions EC.

[0019] 5 is an explanatory diagram showing an example of a window W2 for specifying evaluation conditions EC. In this example, the evaluation conditions EC include the following items: (1) A target color TC to be reproduced with the candidate ink amount set. (2) An evaluation index EI to be calculated for each candidate ink amount set.

[0020] In the example of FIG. 5, data "Gray1.csv" indicating the spectral reflectance of the target color TC is specified as data relating to the target color TC. This spectral reflectance is obtained by performing spectral measurement of a color patch of the target color TC. Note that instead of the spectral reflectance, the target color TC may be specified using the colorimetric value Lab in the CIE-L*a*b* color space or the tristimulus value XYZ in the CIE-XYZ color space. The target color TC may also be specified using a color name associated with the spectral reflectance. When a color name is used, the ink amount calculation unit 130 executes a process of determining candidate ink amount sets using the spectral reflectance defined in association with the specified color name.

[0021] As the evaluation index EI, for example, one or more of the following can be used. (a) Color reproducibility index CRI. (b) Color difference evaluation index (CDI). (c) Light source dependence index SDI. (d) Total ink volume TIA. (e) Graininess index GI.

[0022] The color reproducibility index CRI is the color difference between a candidate color, which is a color reproduced by a candidate ink amount set, and a target color TC. The colorimetric value Lab of the candidate color can be obtained by predicting the spectral reflectance from the candidate ink amount set using the color prediction model 132, calculating the tristimulus values ​​XYZ under observation conditions using a specific light source using the spectral reflectance, and converting the tristimulus values ​​XYZ into the colorimetric value Lab. The colorimetric value Lab of the target color TC can be obtained by calculating the tristimulus values ​​XYZ under observation conditions using a specific light source using the spectral reflectance of the target color TC, and converting the tristimulus values ​​XYZ into the colorimetric value Lab. The color reproducibility index CRI is calculated by applying these two colorimetric values ​​Lab to a color difference formula such as CIE DE2000. In this embodiment, D50, which is a standard light source of CIE, is used as the specific light source used to calculate the color reproducibility index CRI. However, other light sources such as D65 may be used. The color reproducibility index CRI is the color difference between a candidate color and a target color TC, so the smaller the CRI, the better.

[0023] The color difference evaluation index CDI indicates a representative value of the color difference between the candidate color reproduced by the ink amount set candidate and the target color TC under a plurality of light sources. In the example of FIG. 5, five light sources excluding F12 are selected from the six standard light sources of D50, D65, A, F8, F10, and F12 as light sources for calculating the color difference evaluation index CDI. In this case, the color difference evaluation index CDI is calculated as a representative value of the five color differences obtained by using each of the five light sources. It is preferable to use the average value as the representative value. However, the maximum value or the median value may be used instead of the average value. In addition, when a place where the printed matter is observed may be assumed, the spectral distribution actually measured at the observation place may 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 a plurality of light sources, the smaller the color difference evaluation index CDI, the better.

[0024] The light source dependency index SDI indicates the difference between the appearance of the candidate color reproduced by the ink amount set candidate under the standard light source and the appearance under the reference light source. One of multiple light sources can be selected as the standard light source, and one or more light sources can be selected as the reference light source. In the example of FIG. 5, D50 is selected as the standard light source, and four standard light sources, D65, A, F8, and F10, are selected as the reference light sources. In this case, the light source dependency index SDI is calculated as a representative value of four color differences calculated from the color measurement value Lab of the candidate color under the standard light source and the color measurement value Lab under each reference light source. It is preferable to use the average value as the representative value. However, the maximum value or the median value may be used instead of the average value. Note that, when a place where the printed matter is observed may be assumed, the spectral distribution actually measured at the observation place may be specified as the standard light source. The light source dependency index SDI indicates the difference between the appearance of the candidate color under the standard light source and the appearance under the reference light source, so the smaller the light source dependency index SDI, the better.

[0025] The total ink amount TIA is the sum of the ink amounts of the candidate ink amount sets. However, if the ink unit price of each color is different, weighting may be applied to each ink color. Also, instead of the total ink amount TIA, the ink amount for each individual ink color may be used as the evaluation index. Basically, a larger ink amount leads to increased costs, so the smaller the ink amount, the better.

[0026] The graininess index GI is an index that indicates the degree of graininess, i.e., noise, felt by an observer when visually observing a printed matter. As the graininess index GI, for example, the graininess index GI described in Patent No. 4388553 of the present applicant can be used. This graininess index GI is calculated as an index that simulates the recording state of dots in a virtual patch reproduced with a candidate ink amount set, and evaluates the spatial frequency of the simulation result. Specifically, the graininess index GI is calculated, for example, by the following formula:

number

[0027] Instead of using the above formula (q1), a graininess prediction model that calculates the graininess index GI from an ink amount set may be created by machine learning, and the graininess prediction model may be used to find the graininess index GI from a candidate ink amount set. In the example of Fig. 5, the use of the graininess prediction model "Ryujo.model" created using machine learning is specified. The smaller the graininess index GI, the better.

[0028] As the items of the evaluation conditions EC, some of those shown in Fig. 5 may be omitted, and items other than these may be added. However, it is preferable that the evaluation conditions EC include at least the evaluation index EI.

[0029] In step S30, the constraint condition specification unit 110 accepts specification of optimization processing conditions OC.

[0030] 6 is an explanatory diagram showing an example of a window W3 for specifying the optimization processing conditions OC. In this example, the optimization processing conditions OC include the following items: (1) An initial ink amount, which is the initial value of the ink amount set. (2) The objective function TF and the target value TV in the optimization process for searching for candidate ink amount sets.

[0031] In the example of Fig. 6, automatic selection of initial ink amounts is specified. Fig. 7 is an explanatory diagram showing the ink amount set table IST used to set the initial values ​​of the ink amount sets. This ink amount set table IST is a group of ink amount sets sampled at equal intervals in the ink amount space CMYKLkLLk. In the example of Fig. 7, sampling is performed at equal intervals of 10%, so the number of ink amount sets is 11. 6 The ink amount calculation section 130 automatically selects initial values ​​that satisfy the constraint condition CC from this ink amount set table IST, and executes a search for ink amount set candidates.

[0032] The color reproducibility index CRI is selected as the objective function TF for the optimization process. Other indices may be used as the objective function TF, or an integrated index including multiple indices may be used. However, it is preferable that the objective function TF includes the color difference between the color reproduced by the candidate ink amount set and the target color TC. The target value TV of the objective function TF can be set arbitrarily by the user according to the type of objective function TF. Note that the optimization process conditions OC may not be set by the user, and pre-set conditions may be used.

[0033] In step S40 of FIG. 3, the ink amount calculation section 130 uses optimization processing to determine a number of candidate ink amount sets ISC capable of reproducing the target color TC.

[0034] Figure 8 is a flowchart showing the processing procedure of step S40. In step S41, the ink amount calculation unit 130 determines an initial value for the ink amount set. In step S42, the ink amount calculation unit 130 searches for one ink amount set candidate ISC by executing an optimization process under the constraint condition CC set in Figure 4. However, when step S42 is executed for the first time, the initial value determined in step S41 is used as is as the ink amount set candidate ISC.

[0035] In step S43, the ink amount calculation section 130 calculates the objective function TF of the ink amount set candidate ISC using the color prediction model 132. As the objective function TF, the color reproducibility index CRI is selected in the optimization processing conditions OC of FIG.

[0036] In step S44, the ink amount calculation unit 130 determines whether the ink amount set candidates ISC have been sufficiently optimized. Specifically, if the objective function TF is equal to or less than a preset target value TV, it is determined that sufficient optimization has been achieved. On the other hand, if the objective function TF is greater than the target value TV, it is determined that sufficient optimization has not been achieved. If sufficient optimization has been achieved, in step S46 the ink amount calculation unit 130 selects one optimal ink amount set candidate ISC, and proceeds to step S47, which will be described later.

[0037] On the other hand, if sufficient optimization has not been achieved, the process proceeds to step S45, where the ink amount calculation unit 130 determines whether or not the termination condition for the optimization process has been met. Specifically, if the number of searches or the search time has reached its upper limit, the termination condition is determined to be met, and if the number of searches or the search time has not reached its upper limit, the termination condition is determined to be not met. If the termination condition has not been met, the process returns to step S42, and the processes from step S42 onwards are executed again. If the termination condition has been met, the process proceeds to step S47.

[0038] In step S47, the ink amount calculation unit 130 determines whether to execute a process of obtaining another ink amount set candidate ISC. In the present embodiment, since a plurality of ink amount set candidates ISC are obtained for one target color TC, when the number of ink amount set candidates ISC has not reached a preset target number, it is determined that the process of obtaining another ink amount set candidate ISC is to be executed. For example, when obtaining another ink amount set candidate ISC by changing the way of giving the initial value of the ink amount set, the number of loop iterations of steps S41 to S48 is equal to the number of initial values of the ink amount set.

[0039] When executing the process of obtaining another ink amount set candidate ISC, in step S48, the conditions of the optimization process are changed. Specifically, for example, by executing one or more of the following changes, the next ink amount set candidate ISC can be searched. (1) Change the initial value of the ink amount set. (2) Change a part of the constraint condition CC. (3) Change the objective function TF. These changes may be made by the user, but it is preferable that the ink amount calculation unit 130 automatically makes them. For example, when a constraint condition such as 0 < K < 100 is given as the duty limit of K ink, as an internal process of the ink amount calculation unit 130, a plurality of variations such as (i) 0 < K < 50, (ii) 0 < K < 80, and (iii) 10 < K < 100 may be set and used as a change in the constraint condition CC.

[0040] 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, it is possible to obtain a plurality of ink amount set candidates ISC. When the process of step S40 ends in this way, the process proceeds to step S50 in FIG. 3.

[0041] In step S50, the evaluation index calculation unit 140 calculates an evaluation index EI for each ink amount set candidate ISC. In the example of Fig. 5, the color reproducibility index CRI, color difference evaluation index CDI, light source dependence index SDI, total ink amount TIA, and graininess index GI have been selected as the evaluation indices EI, so these evaluation indices EI are calculated for each ink amount set candidate ISC. The value of the evaluation index EI is supplied to the notification unit 150 together with the ink amount set candidate ISC. In step S60, the notification unit 150 presents the multiple ink amount set candidates ISC and the evaluation indices EI to the user.

[0042] FIG. 9 is an explanatory diagram showing a window W4 for notifying a plurality of ink amount set candidates ISC. Here, an evaluation index EI is added to each of the plurality of ink amount set candidates ISC found for one target color TC and displayed. The number of ink amount set candidates ISC displayed is set to 20, but FIG. 9 shows only three ink amount set candidates ISC1 to ISC3 as an example. In addition, in this example, a filter is used that displays those with a total ink amount TIA of less than 150. However, a filter using other indices may be applied. In this window W3, it is further possible to sort, that is, rearrange, using any of the five items CRI, CDI, SDI, TIA, and GI of the evaluation index EI. In the example of FIG. 9, the ink amount set candidates ISC are sorted in ascending order of color reproducibility index CRI. Note that sorting may be performed using a combination of multiple items. The user can select one ink amount set candidate ISC that is preferable according to the application from among the plurality of ink amount set candidates ISC. That is, the user can select an appropriate ink quantity set candidate depending on various applications, such as applications in which absolute color reproducibility is prioritized, applications in which the same appearance is desired under various light sources, applications in which reduced ink amounts are desired, etc. In the example of Fig. 9, the second ink quantity set candidate ISC2 has been selected as the ink quantity set suitable for reproducing the target color TC.

[0043] 3, the color replacement table creation unit 160 receives the one ink amount set IAS selected in step S60. The target color TC is also input to the color replacement table creation unit 160.

[0044] In step S80, it is determined whether or not the processing of steps S10 to S70 has been completed. In cases where there are multiple target colors TC, if the processing of steps S10 to S70 has been completed for all target colors TC, the processing is determined to be completed. If the processing is not completed, the processing of steps S10 to S70 is executed again. In step S90, the color replacement table creation unit 160 creates a color replacement table CRT for the printing device 400 using the ink amount set IAS and the target color TC. However, step S90 may be omitted.

[0045] As described above, in this embodiment, a plurality of ink amount set candidates ISC are determined for one target color TC using the constraint conditions CC and evaluation conditions EC specified by the user, and an evaluation index EI is added to each ink amount set candidate ISC and presented to the user, so that the user can easily select an ink amount set suitable for reproducing the target color TC. Furthermore, in this embodiment, an ink amount set suitable for a partial area or color gamut of a printed matter can be freely selected, making it possible to create content that reflects the user's intention. Specifically, for example, it is possible to create content that reflects the user's intention by using an ink amount set that prioritizes ink cost for a target color of a wide background, and using an ink amount set that prioritizes color reproducibility for a special target color such as a corporate color.

[0046] Other forms: The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various forms without departing from the spirit of the present disclosure. For example, the present disclosure can be realized in the following forms. The technical features in the above-mentioned embodiments corresponding to the technical features in each form described below can be appropriately replaced or combined in order to solve some or all of the problems of the present disclosure, or to achieve some or all of the effects of the present disclosure. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0047] (1) According to a first aspect of the present disclosure, there is provided a selection system used to select an ink amount set of a plurality of ink colors for reproducing a target color, the selection system including: a constraint condition specification unit that accepts specification of constraint conditions related to the ink amount set; an evaluation condition specification unit that accepts specification of evaluation conditions including an evaluation index related to the ink amount set; an ink amount calculation unit that obtains a plurality of ink amount set candidates by executing an optimization process under the constraint conditions; an evaluation index calculation unit that calculates the evaluation index for each of the plurality of ink amount set candidates; and a notification unit that adds the evaluation index to each of the plurality of ink amount set candidates and presents them to a user. This selection system allows the user to easily select an ink amount set that is suitable for reproducing the target color from among a plurality of ink amount set candidates.

[0048] (2) In the above selection system, the constraint conditions may include at least one of the following: availability of each of the ink colors, a duty limit for each of the ink colors, and a duty limit for a total ink amount. This selection system allows constraints to be placed on which ink colors to use and how much of each.

[0049] (3) In the above selection system, the evaluation index may include at least one of a color reproducibility index indicating the color difference between a candidate color represented by the ink amount set candidate and the target color under a specific light source, a color difference evaluation index indicating a representative value of the color difference between the candidate color and the target color under multiple light sources, a light source dependency index indicating the difference between the appearance of the candidate color under a standard light source and the appearance under a reference light source, a total ink amount of the ink amount set candidate, and a graininess index of a printed matter reproduced with the ink amount set candidate. According to this selection system, index values ​​for various evaluation indices can be presented together with the ink amount set.

[0050] (4) In the above selection system, the ink amount calculation unit may determine the multiple ink amount set candidates by performing at least one of the following in the optimization process: (i) changing an ink amount set initial value, (ii) changing the constraint condition, and (iii) changing an objective function. This selection system makes it possible to find multiple ink amount set candidates under a variety of conditions.

[0051] (5) According to a second aspect of the present disclosure, there is provided a method for selecting an ink quantity set of a plurality of ink colors for reproducing a target color, the method comprising the steps of: (a) accepting a designation of constraint conditions for the ink quantity set; (b) accepting a designation of evaluation conditions including an evaluation index for the ink quantity set; (c) determining a plurality of ink quantity set candidates by performing an optimization process under the constraint conditions; (d) calculating the evaluation index for each of the ink quantity set candidates; and (e) adding the evaluation index to each of the ink quantity set candidates and presenting them to a user.

[0052] (6) According to a third aspect of the present disclosure, there is provided a computer program for selecting an ink quantity set of a plurality of ink colors for reproducing a target color. This computer program causes a computer to execute the following processes: (a) accepting specification of constraint conditions related to the ink quantity set, (b) accepting specification of evaluation conditions including evaluation indexes related to the ink quantity set, (c) determining a plurality of ink quantity set candidates by executing an optimization process under the constraint conditions, (d) calculating the evaluation indexes for each of the plurality of ink quantity set candidates, and (e) adding the evaluation indexes to each of the plurality of ink quantity set candidates and presenting them to a user.

[0053] The present disclosure may be realized in various forms other than an image processing device, a printing system, and a computer program, for example, an image processing method, a non-transitory storage medium on which a computer program is recorded, and the like. [Explanation of symbols]

[0054] 100... image processing device, 101... processor, 102... memory, 103... input / output interface, 104... internal bus, 110... constraint condition designation unit, 120... evaluation condition designation unit, 130... ink amount calculation unit, 132... color prediction model, 140... evaluation index calculation unit, 150... notification unit, 160... color replacement table creation unit, 200... input device, 300... display device, 400... printing device, 500... printing system

Claims

1. 1. A selection system for selecting an ink amount set of a plurality of ink colors for reproducing a target color, comprising: a constraint condition specification unit that accepts specification of a constraint condition related to the ink amount set; an evaluation condition designation unit that accepts designation of evaluation conditions including evaluation indices related to the ink amount set; an ink amount calculation unit that obtains a plurality of ink amount set candidates by executing an optimization process under the constraint conditions; an evaluation index calculation unit that calculates the evaluation index for each of the plurality of ink amount set candidates; a notification unit that presents the evaluation index to the plurality of ink amount set candidates to a user; A selection system comprising:

2. 2. The selection system of claim 1, The constraint conditions include at least one of: availability of each of the ink colors, a duty limit for each of the ink colors, and a duty limit for a total ink amount.

3. 2. The selection system of claim 1, A selection system, wherein the evaluation index includes at least one of a color reproducibility index indicating the color difference between a candidate color represented by the ink amount set candidate and the target color under a specific light source, a color difference evaluation index indicating a representative value of the color difference between the candidate color and the target color under multiple light sources, a light source dependency index indicating the difference between the appearance of the candidate color under a standard light source and the appearance under a reference light source, a total ink amount of the ink amount set candidate, and a graininess index of the printed material reproduced with the ink amount set candidate.

4. 2. The selection system of claim 1, The ink amount calculation unit, in the optimization process, (i) changing the initial ink amount set value; (ii) modifying said constraints; and (iii) changing the objective function; a selection system for determining the plurality of candidate ink quantity sets by performing at least one of the following:

5. 1. A method for selecting an ink amount set of a plurality of ink colors for reproducing a target color, comprising the steps of: (a) receiving a specification of a constraint condition related to the ink amount set; (b) receiving a designation of evaluation conditions including an evaluation index related to the ink amount set; (c) determining a plurality of ink amount set candidates by performing an optimization process under the constraints; (d) calculating the evaluation index for each of the plurality of ink amount set candidates; (e) adding the evaluation index to each of the plurality of ink amount set candidates and presenting the result to a user; A method for providing the above.

6. 1. A computer program for selecting an ink amount set of a plurality of ink colors for reproducing a target color, comprising: (a) receiving a specification of a constraint condition related to the ink amount set; (b) receiving designation of evaluation conditions including evaluation indices related to the ink amount set; (c) determining a plurality of ink amount set candidates by performing an optimization process under the constraints; and (d) calculating the evaluation index for each of the plurality of ink amount set candidates; (e) adding the evaluation index to each of the plurality of ink amount set candidates and presenting the result to a user; A computer program that causes a computer to execute the following:

Images