Color prediction model creating method, color prediction model creating device, printing system, and computer program

Abstract

To provide a technique for creating a color prediction mode in consideration of the type of a color patch that is considered to be important by a user.SOLUTION: A method for creating a color prediction model includes a step of (a) accepting process settings for creating a color prediction model, the process settings including an arrangement priority setting for a plurality of attributes for N color patches represented by color chart data, and a step of (b) creating a color prediction model according to the process settings. The step of (b) includes a step of (b1) printing a color chart by a printing device using the color chart data, a step of (b2) acquiring a measurement result of the spectral reflectance of a color chart, a step of (b3) creating learning data including the measurement result of the spectral reflectance, and a step of (b4) executing learning of the color prediction model using the learning data. In the step of (b1), the color chart is printed in a state where M color patches are arranged according to the arrangement priorities.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a method for creating a color prediction model, a color prediction model creating device, a printing system, and a computer program. [Background technology]

[0002] In the printing device, a color conversion process is performed to convert the color values ​​of the input image data expressed in a first color system into color values ​​in a second color system corresponding to the type of ink. In the color conversion process, a plurality of color conversion tables for associating the color values ​​of the first color system with the color values ​​of the second color system are referenced. When creating such a color conversion table, a color prediction model is used that predicts the spectral reflectance of a printed matter printed with an arbitrary ink amount set from the ink amount set. Patent Document 1 disclosed by the applicant of the present disclosure discloses a method for creating a teacher data set for a color prediction model by repeating data selection and learning from a group of virtual teacher data candidates created using a pre-model. According to this method, the prediction accuracy of the color prediction model can be efficiently improved by additionally selecting teacher data for the color prediction model. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-128280 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, it is not always desirable to spend a long time working to create a color prediction model with the highest accuracy, and there are cases where a color prediction model that can predict color patches in the entire color space with high accuracy is not necessary. For example, there are cases where high prediction accuracy is required only for color patches in a part of the color gamut, or only for color patches of secondary colors or lower. In addition, as the use of color prediction models becomes more widespread, it has become necessary to balance prediction accuracy and work time depending on the application. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a method for creating a color prediction model for predicting a spectral reflectance from an ink amount set of a plurality of types of ink constituting an ink set. The method includes: (a) accepting a process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer of 2 or more, as a process setting for creating the color prediction model; and (b) creating the color prediction model according to the process setting. The process (b) includes: (b1) printing a color chart by a printing device using the color chart data; (b2) acquiring a measurement result of the spectral reflectance of the color chart; (b3) creating learning data including the measurement result of the spectral reflectance; and (b4) learning the color prediction model using the learning data. In the process (b1), the color chart is printed with M color patches arranged according to the arrangement priority, where M is an integer of 2 or more and N or less.

[0006] According to a second embodiment of the present disclosure, there is provided a color prediction model creation device that creates a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set. The color prediction model creation device includes a process setting unit that accepts process settings including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data as process settings related to the creation of the color prediction model, where N is an integer of 2 or more, and a model creation unit that creates the color prediction model according to the process settings. The model creation unit includes a print execution unit that uses the color chart data to print a color chart with a printing device, a measurement result acquisition unit that acquires a measurement result of the spectral reflectance of the color chart, a learning data creation unit that creates learning data including the measurement result of the spectral reflectance, and a learning unit that executes learning of the color prediction model using the learning data. When M is an integer of 2 or more and N or less, the print execution unit prints the color chart in a state in which M color patches are arranged according to the arrangement priority.

[0007] According to a third embodiment of the present disclosure, a printing system is provided. The printing system includes a color prediction model creation device that creates a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set, and a printing device. The color prediction model creation device includes a process setting unit that accepts a process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data as a process setting related to the creation of the color prediction model, where N is an integer of 2 or more, and a model creation unit that creates the color prediction model according to the process setting. The model creation unit includes a print execution unit that uses the color chart data to print a color chart with the printing device, a measurement result acquisition unit that acquires a measurement result of the spectral reflectance of the color chart, a learning data creation unit that creates learning data including the measurement result of the spectral reflectance, and a learning unit that uses the learning data to execute learning of the color prediction model. When M is an integer of 2 or more and N or less, the print execution unit prints the color chart in a state in which M color patches are arranged according to the arrangement priority.

[0008] According to a fourth aspect of the present disclosure, there is provided a computer program for creating a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set. The computer program causes a computer to execute (a) a process setting for accepting a process setting for creating the color prediction model, the process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer of 2 or more, and (b) a process for creating the color prediction model according to the process setting. The process (b) includes (b1) a process for printing a color chart by a printing device using the color chart data, (b2) a process for acquiring a measurement result of the spectral reflectance of the color chart, (b3) a process for creating learning data including the measurement result of the spectral reflectance, and (b4) a process for learning the color prediction model using the learning data. When M is an integer of 2 or more and N or less, in the process (b1), the color chart is printed in a state in which M color patches are arranged according to the arrangement priority. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram of a printing system. [Diagram 2] FIG. 4 is an explanatory diagram showing an example of color chart information. [Diagram 3] 11 is a flowchart showing the procedure of a process for creating a color prediction model. [Figure 4] FIG. 4 is an explanatory diagram showing an example of a print setting window. [Diagram 5] FIG. 4 is an explanatory diagram showing an example of a color measurement setting window. [Figure 6] FIG. 11 is an explanatory diagram showing an example of a window for selecting color chart data. [Figure 7] FIG. 13 is an explanatory diagram showing an example of a priority setting window. [Figure 8] FIG. 13 is an explanatory diagram showing another example of the priority setting window. [Figure 9] FIG. 11 is an explanatory diagram showing an example of a color chart printed in accordance with priority settings. [Figure 10] FIG. 1 is an explanatory diagram showing an example of a printing device including a color measurement device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1 is a block diagram showing a schematic configuration of a printing system according to an embodiment of the present invention. The printing system 500 includes a color prediction model creation device 100, a printing device 200, a color measurement device 300, and a display device 400.

[0011] The color prediction model creation device 100 creates a color prediction model CM that predicts the spectral reflectance of a printed material printed with an ink amount set used in the printing device 200, from that ink amount set. An "ink amount set" refers to a combination of ink amounts of multiple types of ink that can be used in the printing device 200. A combination of multiple types of ink that can be used in the printing device 200 is called an "ink set."

[0012] The color prediction model creation device 100 is a computer including a CPU 50, a storage unit 60, and an input / output interface 70. The CPU 50, the storage unit 60, and the input / output interface 70 are connected via an internal bus so as to be able to communicate bidirectionally.

[0013] The CPU 50 executes a color prediction model creation program 61 pre-stored in the storage unit 60, thereby functioning as a processing setting unit 51, a print execution unit 52, a measurement result acquisition unit 53, a learning data creation unit 54, and a learning unit 55. Among these, the print execution unit 52, the measurement result acquisition unit 53, the learning data creation unit 54, and the learning unit 55 constitute a model creation unit 56. Note that at least a part of the functions of these units 51 to 55 may be realized by a hardware circuit, or may be realized on the cloud.

[0014] The process setting unit 51 accepts various process settings related to the creation process of the color prediction model CM. The process settings include the setting of the arrangement priority for a plurality of attributes related to a plurality of color patches represented by the color chart data 62. The contents of the process settings will be described in more detail later.

[0015] The model creation unit 56 executes a process of creating a color prediction model CM in accordance with the process settings set by the process setting unit 51. The process contents of the units 51 to 55 included in the model creation unit 56 are as follows.

[0016] The print execution unit 52 prints a color chart CC by the printing device 200 using one color chart data 62 selected from the multiple color chart data 62. When N is an integer equal to or greater than 2, one color chart data 62 is configured to represent N color patches. When M is an integer equal to or greater than 2 and equal to or less than N, the color chart CC is printed in a state in which M of the N color patches are arranged according to the arrangement priority set by the process setting unit 51. The arrangement and printing of the color patches will be described in more detail below.

[0017] The measurement result acquisition unit 53 causes the colorimetric device 300 to measure the spectral reflectance R(λ) of the printed color chart CC, and acquires the measurement result.

[0018] The learning data creation unit 54 creates learning data including the measurement results of the spectral reflectance R(λ). The learning data is data showing the correspondence between the ink amount set and the spectral reflectance R(λ) for each of the multiple color patches represented by the color chart data 62. The learning data creation unit 54 has a function of creating learning data for unmeasured color patches among the N color patches, whose spectral reflectance R(λ) has not been measured, using the predicted spectral reflectance predicted by the simplified color prediction model SM. The simplified color prediction model SM is a model that can be trained more easily than the color prediction model CM. The meaning of "easily trainable" means that the amount of data in the training data is small and the training time is short. The simplified color prediction model SM is a model that predicts the spectral reflectance from the ink amount set, and can be configured as a color prediction model based on the known spectral Neugebauer model, for example. As a color prediction model based on the spectral Neugebauer model, the printing model described in JP 2006-334945 A can be used. Note that a color prediction model other than the spectral Neugebauer model may be used as the simplified color prediction model. However, it is preferable that the simplified color prediction model SM requires less learning data and a shorter learning time than the finally created color prediction model CM. It is preferable that the learning of the simplified color prediction model SM is completed using learning data for the simplified color prediction model SM that has been created in advance.

[0019] The learning unit 55 uses the learning data to execute learning of the color prediction model CM.

[0020] In addition to the color prediction model creation program 61, the storage unit 60 stores a plurality of color chart data 62 and color chart information 63. The color chart data 62 is image data representing a color chart including a plurality of single-color color patch groups and a plurality of mixed-color color patch groups. The pixel values ​​of the color chart data 62 are represented by ink amount sets. In this embodiment, a plurality of color chart data 62 are created in advance and stored in the storage unit 60. The color chart information 63 is information relating to each individual color chart data 62. The contents of the color chart information 63 will be described later.

[0021] The printing device 200 has a plurality of ink containers 210, each of which contains one type of ink. In this embodiment, the number of ink containers 210 is six, and an ink set containing six types of ink, CMYKLcLm, can be used. Here, C is cyan, M is magenta, Y is yellow, K is black, Lc is light cyan, and Lm is light magenta process ink. The printing device 200 may be configured to be able to use spot color inks. Also, not only the ink color type but also the number of ink colors can be set arbitrarily.

[0022] The input / output interface 70 transmits images such as the color chart data 62 to the printing device 200, and also receives color measurement results of the print image printed on the printing medium P from the color measurement device 300. The input / output interface 70 further transmits display images to the display device 400, and displays various windows and processing results, which will be described later.

[0023] The printing device 200 is an inkjet printer that prints an image on the printing medium P by ejecting ink onto the printing medium P. Upon receiving color chart data 62 from the color prediction model creation device 100, the printing device 200 prints a color chart CC on the printing medium P in response to the color chart data 62.

[0024] The color measurement device 300 measures the color of a printed matter produced by the printing device 200. The color measurement device 300 measures the spectral reflectance R(λ) of each of a plurality of color patches included in the color chart CC. The measured spectral reflectance R(λ) is supplied to the color prediction model creation device 100.

[0025] 2 is an explanatory diagram showing an example of the color chart information 63. The color chart information 63 is information in which five items are registered for each color chart data 62: (1) media name, (2) media surface type, (3) ink set, (4) color chart data name, and (5) auxiliary information.

[0026] In this disclosure, "media" refers to print media. In the example of Fig. 2, four media names, Photo_A, Photo_B, Mat_A, and Mat_B, are presented. As described in the media surface type column, Photo_A and Photo_B are glossy paper, and Mat_A and Mat_B are matte paper. Two types of ink sets, CMYK and CMYKLcLm, are presented.

[0027] "Ink set CMYK" means one of the following: (a) Ink set for a printing device equipped with only CMYK inks. (b) An ink set used in a printing mode that does not use inks other than CMYK (Lc ink and Lm ink) among the CMYKLcLm inks installed in the printing device. It is usually used in the sense of (a) above, but it may also be used in the sense of (b) above.

[0028] As auxiliary information, whether or not the color chart data for Photo_A and Photo_B can be used to create a color prediction model for Photo_C is registered. Specifically, the color chart data for Photo_A can be used to create a color prediction model for Photo_C, and the color chart data for Photo_B cannot be used to create a color prediction model for Photo_C. Photo_C is a medium that has color development characteristics similar to those of Photo_A.

[0029] The reason why color chart data for Photo_C is not prepared and the fact that it can be substituted with other media is registered in the auxiliary information is that it is practically difficult to prepare color chart data for all media that are expected to be used. For this reason, in this embodiment, it is assumed that color chart data will be prepared for representative media and that the color chart data will be used for media with similar characteristics.

[0030] It should be noted that some of the five items illustrated in FIG. 2 may be omitted, for example, the auxiliary information may be omitted.

[0031] In the embodiment described below, one piece of color chart data 62 is selected using color chart information 63. After the selected color chart data 62 is reconstructed, the color chart CC is printed, the spectral reflectance is measured, learning data is created, and the color prediction model CM is learned in this order. However, the color chart data to be referenced may be automatically selected when print settings are made (described later) without using the color chart information 63.

[0032] 3 is a flowchart showing the procedure of the process of creating a color prediction model. In step S10, the process setting unit 51 accepts various process settings related to the process of creating the color prediction model CM. The process settings include (1) print settings, (2) color measurement settings, (3) selection of color chart data, and (4) priority settings. These process settings will be described in order below.

[0033] 4 is an explanatory diagram showing an example of a print setting window W1. Using this window W1, the user can set four items related to printing the color chart CC: (1) media name, (2) number of passes, (3) duty limit value, and (4) whether or not to perform color correction.

[0034] "Number of passes" refers to the number of main scans of the print head required to print all the pixels on one main scan line. For example, "4 passes" means that all the pixels on one main scan line are printed by performing four main scans. It is also possible to select, for example, 1 pass or 2 passes as the number of passes.

[0035] The "duty limit value" is the upper limit of the total amount of ink permitted to be ejected per pixel. In the example of Figure 4, the duty limit value to be used for actual printing can be specified, taking into consideration cases where the media selected in the print settings differs from the media used for actual printing. In this case, the amount of ink ejected per pixel during actual printing is corrected as follows, taking into consideration the specified duty limit value. Vc = V × (Dt_set / Dt_pre) …(q1) Here, Vc is the corrected ink amount, V is the original ink amount, Dt_set is the duty limit value specified in the print settings, and Dt_pre is the duty limit value set when the color chart data 62 was created. Normally, Dt_set is set to a value equal to or less than Dt_pre. However, Dt_set may be set to a value greater than Dt_pre.

[0036] When a duty limit value is set in the print settings, it is preferable to correct the ink amount using the above formula (q1) before determining the arrangement of the color patches according to the arrangement priority, which will be described later.

[0037] For "color correction," you can specify either no color correction or color correction. The "no color correction" setting means that when using a RIP (Raster Image Processor) or other process to print a color chart CC, the color management function is turned off so that no color correction is performed.

[0038] Note that some of the four items that can be set in the print setting window W1 may be omitted, and other items may be added. This also applies to the windows for other process settings described below.

[0039] 5 is an explanatory diagram showing an example of the color measurement setting window W2. Using this window W2, the user can set three items related to the spectral reflectance measurement of the printed color chart CC: (1) the measurement device, (2) the measurement method, and (3) the number of measurements.

[0040] "Measurement device" is a setting of identification information of the color measurement device 300. As the identification information, a model number or a device name can be used.

[0041] As the "measurement method," a measurement method that can be performed by the colorimetric device 300 can be selected. Two measurement methods are generally known: spot colorimetry and scan colorimetry. Spot colorimetry is a method in which the colorimetric device stops at each color patch to measure the color. Scan colorimetry is a method in which multiple color patches are read continuously while the measurement device is moved. Scan colorimetry can complete the measurement of one page's worth of color patches in significantly less work time than spot colorimetry.

[0042] The "number of measurements" can be set to one, or any number of measurements greater than or equal to two. In general, the more measurements are made, the less variation there is in the measurement results of the spectral reflectance, and the more accurate the predictions of the color prediction model CM will be, but the more time it will take to complete the work. Normally, the color measurement device itself is a measuring instrument that has measurement variations, so it is preferable to perform measurements multiple times and calculate the statistical values ​​of the measurements to suppress the measurement variations. When the number of measurements is set to multiple times, in the case of spot colorimetry, the same color is measured a specified number of times before moving to the next color, but in the case of scan colorimetry, the row is scanned a specified number of times. This is also a factor that affects the work time.

[0043] FIG. 6 is an explanatory diagram showing an example of a window W3 for selecting color chart data 62. When the user selects an ink set in this window W3, the attributes of multiple color chart data suitable for that ink set are displayed. In this example, the media name, the surface type of the media, and auxiliary information are displayed as attributes of each color chart data. These attributes are information registered in the color chart information 63 shown in FIG. 2. Also, the window W3 is provided with check boxes CB. The user can select one color chart data by checking one check box CB.

[0044] In the print settings in Fig. 4 described above, Photo_C is selected as the media, and the plurality of color chart data 62 in Fig. 2 does not include any data with Photo_C as the media. Even in this case, auxiliary information indicating that it can be used for Photo_C is displayed in window W3 in Fig. 6, so the user can select one color chart data suitable for Photo_C.

[0045] When Photo_C is selected as the medium in the print settings in Fig. 4, the window W3 in Fig. 6 may be displayed in a state where color chart data that can use Photo_C is automatically selected. In this way, it is possible to automatically present candidates for color chart data that are suitable for the medium selected in the print settings.

[0046] As a list for selecting color chart data 62, a list as shown in Fig. 2 may be used instead of a list as shown in Fig. 6. All of these lists have in common that they include, as setting information suitable for each color chart data 62, print medium information indicating one print medium among a plurality of print media usable in the printing device 200, and ink set information indicating one ink set among a plurality of ink sets usable in the printing device 200. By using such a list, it is possible to select color chart data 62 suitable for a combination of print medium and ink set as the color chart data 62 to be used in creating the color prediction model CM.

[0047] FIG. 7 is an explanatory diagram showing an example of a priority setting window W4a. Using this window W4a, a user can set arrangement priorities for a plurality of attributes related to N color patches represented by the color chart data 62. The arrangement priorities are also simply called "priorities." This window W4a includes three attributes, namely, the color mixing order, the duty, and the color gamut, as attributes for which arrangement priorities can be set. In addition, this window W4a is configured so that a limit value can be set for each attribute.

[0048] The arrangement priority of the "mixing order" is a priority for specifying that the color patches are arranged in order of the smallest mixing order. The "mixing order" is the number of types of ink used to print a color patch. For example, the mixing order of a color patch printed using all six types of ink, CMYKLcLm, is 6. The maximum mixing order, which is the limit value of the mixing order, means the upper limit of the mixing order of the color patch to be printed. For example, when the maximum mixing order is 3, only color patches using three or less types of ink out of the six types of ink, CMYKLcLm, are printed, and color patches using four or more types of ink are excluded from the printing target. If the maximum mixing order is not specified, all color patches are arranged and printed in order of the mixing order.

[0049] The "Duty" arrangement priority is a priority for designating that color patches are arranged in ascending order of duty. "Duty" is the total amount of ink ejected per pixel. The "Duty" limit value means the upper limit of the duty of the color patch to be printed. For example, if the duty limit value is 150%, color patches with a duty of 150% or less are printed, and color patches with a duty exceeding 150% are excluded from the printing target. If the duty limit value is set in the print settings of FIG. 4 described above, it is preferable to correct the ink amount using the above-mentioned formula (q1) before determining whether each color patch is equal to or less than the duty limit value of FIG. 7.

[0050] The arrangement priority of the "color gamut" is a priority for specifying that the color patches are arranged in order of proximity to the designated representative color. In the example of FIG. 7, the representative color of the color gamut is specified by the L*a*b* value. The limit value of the "color gamut" is specified by the color difference ΔE. This limit value means the range of colors of the color patches to be printed. For example, if the representative color of the color gamut is L*a*b*=(50,150,-70) and the limit value ΔE is 3.0, color patches with a color difference ΔE of 3.0 or less from L*a*b*=(50,150,-70) are printed, and color patches with a color difference ΔE of more than 3.0 from L*a*b*=(50,150,-70) are excluded from the printing target. The L*a*b* value of each color patch can be calculated from the predicted value of the spectral reflectance predicted from the ink amount set of the color patch using, for example, the simplified color prediction model SM.

[0051] In the example of FIG. 7, among the three attributes, the arrangement priority of the color mixing order is set to 1, the arrangement priority of the duty is set to 2, and the arrangement priority of the color gamut is set to 3. Therefore, N color patches represented by one color chart data 62 are first arranged in ascending order of color mixing order, then arranged in descending order of duty within the same color mixing order, and then arranged in descending order of proximity to the representative color of the color gamut within the same color mixing order and the same duty. In addition, since limit values ​​are also set for the three attributes, color patches that exceed these limit values ​​are excluded from the printing target. As a result, when the number of color patches printed on the color chart is M, M is an integer between 2 and N.

[0052] FIG. 8 is an explanatory diagram showing another example of the priority setting window W4b. This window W4b may be used instead of the window W4a in FIG. 7. The window W4b in FIG. 8 uses a slider SL to specify the duty limit value, and a pull-down menu PD to specify the representative color of the color gamut. This slider SL is configured so that any position within the range of "low-medium-high" can be specified. The pull-down menu PD is configured so that color names such as gray, sepia, sky blue, etc. can also be selected. Note that various color palettes can also be used as a user interface for specifying the representative color of the color gamut.

[0053] In the examples of Figures 7 and 8, it is not necessary to set the arrangement priority for all three attributes, but it is sufficient to set the arrangement priority for at least one attribute. Also, it is not necessary to set a limit value for the attribute for which the arrangement priority is set. For example, it is possible to set only the arrangement priority of the color mixing order to 1, and not to set a limit value for it. In this case, all of the N color patches represented by one color chart data 62 are printed in a state where they are arranged in order from the lowest color mixing order.

[0054] 7 and 8, one color gamut is specified for the arrangement priority, but multiple color gamuts may be selected. In this case, it is preferable to be able to set an arrangement priority for each of the multiple color gamuts.

[0055] It may be possible to specify the arrangement priority and the limit value for attributes other than the three attributes shown in Figures 7 and 8. Also, it may be possible to specify only the arrangement priority for each attribute, without specifying the limit value.

[0056] Among the various process settings described with reference to FIGS. 4 to 8, items other than the arrangement priority setting may be omitted as appropriate.

[0057] When the above various settings are made by the user, the process proceeds to step S20 in Fig. 3, where the print execution unit 52 adjusts the arrangement and print range of the multiple color patches according to the arrangement priority and limit values ​​of each attribute for the selected color chart data 62. In step S30, the print execution unit 52 supplies the color chart data having the adjusted color patch arrangement to the printing device 200, which prints the color chart CC on the printing medium P. As the printing medium P, the medium set in the print settings in Fig. 4 is used.

[0058] FIG. 9 is an explanatory diagram showing an example of a color chart CC printed according to the priority setting. In this example, a color chart CC printed on a printing medium P according to the priority setting of FIG. 7 is illustrated. A plurality of color patches CP included in this color chart CC are first arranged in ascending order of color mixing order, then arranged in descending order of duty among the same color mixing order, and then arranged in descending order of proximity to the representative color of the color gamut among the same color mixing order and the same duty. In addition, since limit values ​​are also set for the three attributes, color patches CP that exceed these limit values ​​are excluded from being printed. The number M of color patches printed on the color chart CC is less than the number N of color patches represented by one color chart data 62. In the example of FIG. 9, the color chart CC is printed on one printing medium P, but printing of the color chart CC is performed using two or more printing media P as necessary.

[0059] The color chart CC further includes additional information AF related to the arrangement priority at the delimiter positions related to the arrangement priority of the M color patches CP. In the example of FIG. 9, the characters "Primary Color" and a boundary line are printed at the boundary between the rows of the primary color and the secondary color. Furthermore, the characters "Secondary Color" and a boundary line are printed at the boundary between the rows of the secondary color and the tertiary color. If such additional information AF is printed, the relationship between the positions of the color patches CP in the color chart CC and the arrangement priority can be easily recognized. Note that the additional information AF does not need to be printed for all attributes for which an arrangement priority is set, and it is preferable that the additional information AF is printed for at least one attribute with the highest arrangement priority. However, the additional information AF may be omitted.

[0060] The additional information AF may be a numerical value indicating the arrangement priority or a phrase indicating the degree of the arrangement priority printed at a specific position on the right or left side of the color patch CP on the color chart CC. The phrase indicating the degree of the arrangement priority may be, for example, "low", "medium", "high", etc.

[0061] 3, the measurement result acquisition unit 53 acquires the measurement result by having the color measurement device 300 measure the spectral reflectance R(λ) of each color patch CP of the color chart CC. Note that the color measurement device 300 may be implemented within the printing device 200.

[0062] FIG. 10 is an explanatory diagram showing an example of a printing device 200 including a color measurement device 300. In this example, a plurality of color patches CP of a color chart CC are printed on a printing medium P by a head scanning mechanism 220 of the printing device 200. In the feed direction FD of the printing medium P, the color measurement device 300 is disposed at a position downstream of the head scanning mechanism 220. Therefore, immediately after the color patches CP are printed, it is possible to measure the spectral reflectance R(λ) using the color measurement device 300 in the printing device 200. If the printing device 200 has a configuration capable of connecting to a server via a network, the measured spectral reflectance R(λ) may be transmitted to the server, and a color prediction model creation unit implemented in the server may be used to automatically create a color prediction model CM.

[0063] 7 and 8, when the color chart CC is printed without setting limit values ​​for each attribute, the N color patches CP represented by the color chart data 62 are printed in the order of arrangement priority. In this case, the user can stop the color measurement that started from the first page of the color chart CC midway while referring to the additional information AF shown in Fig. 9. For example, the user can stop the color measurement at the point when the user feels that the color mixing order has increased and highly saturated colors have decreased.

[0064] 3, the learning data creation unit 54 predicts the spectral reflectance of unmeasured color patches, whose spectral reflectance has not been measured, among the N color patches represented by the original color chart data 62, using the simplified color prediction model SM. This spectral reflectance is called the "predicted spectral reflectance." If there are no unmeasured color patches, step S50 is omitted.

[0065] In step S60, the learning data creation unit 54 generates learning data including the measurement results of the spectral reflectance R(λ). Each data item in this learning data includes an ink amount set and a spectral reflectance R(λ). For unmeasured color patches, the learning data is created using the predicted spectral reflectance obtained in step S50 instead of the measurement results of the spectral reflectance R(λ).

[0066] In step S70, the learning unit 55 uses the learning data to learn the color prediction model CM. The color prediction model CM can be, for example, a regression model of multidimensional output configured by a neural network. By executing machine learning using the learning data, such a color prediction model CM becomes an inference model that can predict the spectral reflectance from an arbitrary ink amount set of an ink set.

[0067] As described above, in the above embodiment, as a process setting for creating a color prediction model CM, it is possible to set the arrangement priority for multiple attributes related to N color patches represented by the color chart data 62. Furthermore, when M is an integer between 2 and N, a color chart is printed in a state in which M color patches are arranged according to the arrangement priority. As a result, it is possible to create a color prediction model CM by preferentially using color patches with high arrangement priority.

[0068] 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.

[0069] (1) According to a first aspect of the present disclosure, there is provided a method for creating a color prediction model for predicting a spectral reflectance from an ink amount set of a plurality of types of ink constituting an ink set. The method includes: (a) accepting a process setting for creating the color prediction model, where N is an integer equal to or greater than 2, including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data; and (b) creating the color prediction model according to the process setting. The process (b) includes: (b1) printing a color chart by a printing device using the color chart data; (b2) acquiring a measurement result of the spectral reflectance of the color chart; (b3) creating learning data including the measurement result of the spectral reflectance; and (b4) using the learning data to perform learning of the color prediction model. When M is an integer equal to or greater than 2 and equal to or less than N, in the process (b1), the color chart is printed in a state in which M color patches are arranged according to the arrangement priority. According to this method, M color patches are printed arranged according to the arrangement priority, so that the color patches with high arrangement priority can be measured preferentially, and a color prediction model can be created using the colorimetric values.

[0070] (2) In the above method, the plurality of attributes may include one or more of a color mixing order, a duty limit value, and a color gamut. According to this method, a color chart can be printed in a state in which M color patches are arranged in accordance with the arrangement priority relating to the color mixture order, duty limit value, and color gamut of the color patches.

[0071] (3) In the above method, the processing settings may include setting a limit value for the attribute for which the arrangement priority is set, and step (b1) may include a step of printing the color chart so as to include the M color patches up to the limit value and not to include any color patches exceeding the limit value. According to this method, among the N color patches, only M color patches designated by the limit value can be printed.

[0072] (4) In the above method, the step (b3) may include a step of creating the learning data for unmeasured color patches among the N color patches, whose spectral reflectance has not been measured in the step (b2), using predicted spectral reflectances predicted by a simplified color prediction model that can be learned more easily than the color prediction model. According to this method, learning data can be created for color patches whose spectral reflectance has not been actually measured, thereby improving the prediction accuracy of the color prediction model.

[0073] (5) In the above method, the step (b1) may include the step of printing additional information related to the arrangement priority at a separator position related to the arrangement priority of the M color patches on the color chart. According to this method, the relationship between the positions of the color patches and the arrangement priority can be easily recognized.

[0074] (6) In the above method, the process setting may include a setting indicating selection of one color chart data to be used for creating the color prediction model from a plurality of color chart data created in advance, and the step (a) may include a step of displaying a list indicating the plurality of color chart data. The list may include, as setting information suitable for each color chart data, print medium information indicating one print medium among a plurality of print media usable by the printing device, and ink set information indicating one ink set among a plurality of ink sets usable by the printing device. According to this method, it is possible to select color chart data suitable for the combination of printing medium and ink set as the color chart data used to create the color prediction model.

[0075] (7) According to a second aspect of the present disclosure, there is provided a color prediction model creation device that creates a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set. The color prediction model creation device includes a process setting unit that accepts process settings including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data as process settings related to the creation of the color prediction model, where N is an integer of 2 or more, and a model creation unit that creates the color prediction model according to the process settings. The model creation unit includes a print execution unit that uses the color chart data to print a color chart with a printing device, a measurement result acquisition unit that acquires a measurement result of the spectral reflectance of the color chart, a learning data creation unit that creates learning data including the measurement result of the spectral reflectance, and a learning unit that executes learning of the color prediction model using the learning data. Where M is an integer of 2 or more and N or less, the print execution unit prints the color chart in a state in which M color patches are arranged according to the arrangement priority.

[0076] (8) According to a third embodiment of the present disclosure, a printing system is provided. The printing system includes a color prediction model creation device that creates a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set, and a printing device. The color prediction model creation device includes a process setting unit that accepts a process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data as a process setting related to the creation of the color prediction model, where N is an integer of 2 or more, and a model creation unit that creates the color prediction model according to the process setting. The model creation unit includes a print execution unit that uses the color chart data to print a color chart with the printing device, a measurement result acquisition unit that acquires a measurement result of the spectral reflectance of the color chart, a learning data creation unit that creates learning data including the measurement result of the spectral reflectance, and a learning unit that uses the learning data to execute learning of the color prediction model. When M is an integer of 2 or more and N or less, the print execution unit prints the color chart in a state in which M color patches are arranged according to the arrangement priority.

[0077] (9) According to a fourth aspect of the present disclosure, there is provided a computer program for creating a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set. The computer program causes a computer to execute (a) a process of receiving a process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer of 2 or more, as a process setting related to the creation of the color prediction model, and (b) a process of creating the color prediction model according to the process setting. The process (b) includes (b1) a process of printing a color chart by a printing device using the color chart data, (b2) a process of acquiring a measurement result of the spectral reflectance of the color chart, (b3) a process of creating learning data including the measurement result of the spectral reflectance, and (b4) a process of learning the color prediction model using the learning data. When M is an integer of 2 or more and N or less, in the process (b1), the color chart is printed in a state in which M color patches are arranged according to the arrangement priority.

[0078] 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]

[0079] 50...CPU, 51...processing setting unit, 52...print execution unit, 53...measurement result acquisition unit, 54...learning data creation unit, 55...learning unit, 56...model creation unit, 60...storage unit, 61...color prediction model creation program, 62...color chart data, 63...color chart information, 70...input / output interface, 100...color prediction model creation device, 200...printing device, 210...ink container, 220...head scanning mechanism, 300...color measurement device, 400...display device, 500...printing system

Claims

1. A method for creating a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set, comprising the steps of: (a) receiving a process setting for generating the color prediction model, the process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer equal to or greater than 2; (b) generating the color prediction model according to the processing settings; Equipped with The step (b) (b1) printing a color chart by a printing device using the color chart data; (b2) obtaining a measurement result of the spectral reflectance of the color chart; (b3) creating learning data including the measurement results of the spectral reflectance; (b4) performing training of the color prediction model using the training data; and Equipped with wherein, in the step (b1), the color chart is printed in a state in which M color patches are arranged according to the arrangement priority, where M is an integer between 2 and N.

2. 2. The method of claim 1 , The method, wherein the plurality of attributes includes one or more of a color mixing order, a duty limit value, and a color gamut.

3. 2. The method of claim 1 , the processing setting includes setting a limit value for the attribute for which the arrangement priority is set; The method, wherein step (b1) comprises printing the color chart to include the M color patches up to the limit value and to include no color patches exceeding the limit value.

4. 4. The method of claim 3, the step (b3) includes a step of creating the learning data for unmeasured color patches among the N color patches, whose spectral reflectance has not been measured in the step (b2), using predicted spectral reflectances predicted by a simplified color prediction model that can be learned more easily than the color prediction model.

5. 2. The method of claim 1 , The method, wherein the step (b1) includes a step of printing additional information related to the arrangement priority at a separation position related to the arrangement priority of the M color patches on the color chart.

6. 2. The method of claim 1 , the processing setting includes a setting indicating that one color chart data to be used for creating the color prediction model is selected from a plurality of color chart data created in advance, The step (a) includes a step of displaying a list showing the plurality of color chart data, The method, wherein the list includes, as setting information suitable for each color chart data, print medium information indicating one print medium among a plurality of print media usable by the printing device, and ink set information indicating one ink set among a plurality of ink sets usable by the printing device.

7. A color prediction model creation device that creates a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set, comprising: a process setting unit that receives process settings related to the creation of the color prediction model, the process settings including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer equal to or greater than 2; a model creation unit that creates the color prediction model in accordance with the processing settings; Equipped with The model creation unit is a print execution unit that prints a color chart using the color chart data by a printing device; a measurement result acquisition unit that acquires a measurement result of the spectral reflectance of the color chart; a learning data creation unit that creates learning data including the measurement results of the spectral reflectance; a learning unit that uses the learning data to learn the color prediction model; Including, a color prediction model creating device, wherein, when M is an integer between 2 and N, the printing execution unit prints the color chart in a state in which M color patches are arranged according to the arrangement priority;

8. 1. A printing system comprising: a color prediction model creating device that creates a color prediction model that predicts a spectral reflectance from an ink amount set of a plurality of types of ink that constitute an ink set; A printing device; Equipped with The color prediction model creating device comprises: a process setting unit that receives process settings related to the creation of the color prediction model, the process settings including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer equal to or greater than 2; a model creation unit that creates the color prediction model in accordance with the processing settings; Equipped with The model creation unit is a print execution unit that prints a color chart by the printing device using the color chart data; a measurement result acquisition unit that acquires a measurement result of the spectral reflectance of the color chart; a learning data creation unit that creates learning data including the measurement results of the spectral reflectance; a learning unit that uses the learning data to learn the color prediction model; Including, a printing system, wherein, when M is an integer between 2 and N, the printing execution unit prints the color chart in a state in which M color patches are arranged according to the arrangement priority;

9. A computer program for creating a color prediction model for predicting a spectral reflectance from an ink amount set of a plurality of types of ink constituting an ink set, comprising: (a) receiving a process setting for generating the color prediction model, the process setting including a setting of an arrangement priority for a plurality of attributes related to N color patches represented by color chart data, where N is an integer equal to or greater than 2; (b) creating the color prediction model in accordance with the process settings; Run the following on your computer: The process (b) (b1) a process of printing a color chart by a printing device using the color chart data; (b2) acquiring a measurement result of the spectral reflectance of the color chart; (b3) creating learning data including the measurement results of the spectral reflectance; (b4) a process of executing learning of the color prediction model using the learning data; and Including, wherein, in the process (b1), the color chart is printed in a state in which M color patches are arranged according to the arrangement priority, where M is an integer between 2 and N.

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