Method for generating proof image data, proof image data generating device, and computer program

Abstract

To provide a technique to reflect the influence of bleeding on proof image data.SOLUTION: A method for generating proof image data includes: (a) a step of acquiring printing characteristic information including a bleeding parameter representing a bleeding state in a print that is printed on a print medium by using a printer; (b) a step of acquiring basic proof image data for reproducing the color of the print by using a proof output device; and (c) a step of generating bleeding added proof image data simulating the bleeding state by applying bleeding adding processing to the basic proof image data by using the printing characteristic information.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a method for creating proof image data, a proof image data creation device, and a computer program. [Background technology]

[0002] Patent Document 1 discloses a method for creating a proof image for proofreading a printed matter. In this conventional technology, a proof image is created by correcting an image based on the density distribution in two-dimensional space on the surface of a printed matter printed at 100% density on a printing medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-270930 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the inventors of the present disclosure have discovered that the impact of ink bleeding is significant in prints printed on certain print media, such as fabric, and that the impact of bleeding should be taken into consideration when creating a proof image. Bleeding occurs when ink that has landed on the print medium spreads, mixes with adjacent inks, or flows due to the unevenness of the print medium before soaking into the print medium. Therefore, in order to faithfully reproduce the state of the print, it is desirable to reflect the impact of bleeding in the proof image data. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a method for creating proof image data, the method including: (a) acquiring printing characteristic information for a printed matter to be printed on a printing medium using a printing press, the printing characteristic information including bleeding parameters representing a bleeding state in the printed matter, (b) acquiring basic proof image data for reproducing the color of the printed matter using a proof output device, and (c) applying a bleeding process to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state.

[0006] According to a second aspect of the present disclosure, there is provided a proof image data creation device including a printing characteristic information acquisition unit that acquires printing characteristic information including bleeding parameters that represent a bleeding state in a printed matter printed on a printing medium using a printing press, a basic proof image acquisition unit that acquires basic proof image data for reproducing the color of the printed matter on a proof output device, and a bleeding processing unit that applies a bleeding process to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state.

[0007] According to a third aspect of the present disclosure, there is provided a computer program for creating proof image data, which causes a computer to execute the following steps: (a) acquiring printing characteristic information for a printed matter to be printed on a printing medium using a printing press, the processing including bleeding parameters representing a bleeding state in the printed matter; (b) acquiring basic proof image data for reproducing the color of the printed matter using a proof output device; and (c) applying a bleeding process to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing a printing system for proofreading a printed material. [Figure 2] FIG. 1 is a block diagram showing the configuration of a proof image data creation device. [Figure 3] FIG. 4 is an explanatory diagram showing the flow of proof image creation processing. [Figure 4] FIG. 4 is an explanatory diagram showing a printing condition setting screen. [Figure 5] FIG. 10 is an explanatory diagram showing an example of a basic proof image. [Figure 6] FIG. 10 is an explanatory diagram showing an example of texture information. [Figure 7] FIG. 4 is an explanatory diagram showing an example of printing characteristic information. [Figure 8] FIG. 10 is an explanatory diagram showing an example of a bleeding process in a texture-dependent mode. [Figure 9] FIG. 10 is an explanatory diagram showing another example of the bleeding imparting process in the texture-dependent mode. [Figure 10] FIG. 10 is an explanatory diagram showing an example of a bleeding process in a texture-independent mode. [Figure 11] 10A and 10B are explanatory diagrams showing differences in bleeding processing depending on printing characteristic information. [Figure 12] FIG. 10 is an explanatory diagram showing an example of texture applying processing. [Figure 13] FIG. 10 is an explanatory diagram showing texture imparting processing involving unevenness correction of texture information. [Figure 14] 10 is a flowchart showing the procedure of a process for creating proof image data. DETAILED DESCRIPTION OF THE INVENTION

[0009] FIG. 1 is an explanatory diagram showing a printing system 500 for proofing printed materials. This printing system 500 includes a printing machine 300 that prints printed materials PM according to input image data IM, a proof image data creation device 100 that creates proof image data using the input image data IM, a proof printing device 200, and a cloud server 400. Proofing can be performed using hard proofing, in which a proof print HP is printed using the proof printing device 200, or soft proofing, in which a proof image SP is displayed on a display device 150 according to the proof image data. In hard proofing, the proof printing device 200 corresponds to the "proof output device," while in soft proofing, the display device 150 corresponds to the "proof output device." The image output from the proof output device is also called the "output image." In hard proofing, the proof print HP corresponds to the "output image," while in soft proofing, the proof image SP corresponds to the "output image."

[0010] The proof image data creation device 100 is configured to be able to perform at least one of hard proofing and soft proofing. In hard proofing, the proof printing device 200 prints a proof HP according to the proof image data created by the proof image data creation device 100. If the proof printing device 200 is an inkjet printer, the proof image data creation device 100 applies color conversion processing and halftone processing to the proof image data to create dot data for printing, and supplies this dot data to the proof printing device 200 to print the proof HP. In soft proofing, a proof image SP is displayed on the display device 150 according to the proof image data created by the proof image data creation device 100. The present disclosure is applicable to both hard proofing and soft proofing.

[0011] The printing machine 300 is, for example, a textile printing machine that performs textile printing on a printing medium made of cloth. The print PM printed on a printing medium made of cloth is significantly affected by ink bleeding. Types of printing machines 300 will be described in more detail below. The proof image data creation device 100 creates proof image data with bleeding added to faithfully reproduce the state of the print PM. However, the present disclosure is also applicable to cases where the printing machine 300 prints on a printing medium other than cloth.

[0012] The cloud server 400 includes a printing press database 410 and a print medium database 420. The printing press database 410 is a database in which printing characteristic information PCI, including bleeding parameters ZP, is registered for multiple models of printing presses 300. The bleeding parameters ZP are parameters that represent the bleeding state in the printed material PM. The contents of the printing characteristic information PCI and the bleeding parameters ZP will be described later. The print medium database 420 is a database in which texture information TI is registered for multiple types of print media. Note that the registered contents of the printing press database 410 and the print medium database 420 may be registered in a single integrated database. The cloud server 400 may also be configured to provide multiple ICC profiles for performing various color conversion processes.

[0013] The proof image data creation device 100 acquires information from the cloud server 400 and uses the information to perform various processes described below. However, the information provided by the cloud server 400 may be stored in advance in a storage device of the proof image data creation device 100.

[0014] 2 is a block diagram showing the configuration of the proof image data creation device 100. The proof image data 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 to enable bidirectional communication.

[0015] The CPU 50 executes a proof image creation program 61 stored in advance in the storage unit 60, thereby functioning as a printing characteristic information acquisition unit 110, a basic proof image acquisition unit 120, a bleed processing unit 130, and a texture applying unit 140. The bleed processing unit 130 includes an edge extraction unit 131 and a bleed applying unit 132. At least some of the functions of these units 110 to 140 may be realized by a hardware circuit or on the cloud.

[0016] The input / output interface 70 is connected to the display device 150 and the proof printing device 200 by wire or wirelessly, and is further connected to the cloud server 400 via the Internet. The display device 150 is used to display windows and proof images, which will be described later.

[0017] 3 is an explanatory diagram showing the flow of the proof image creation process. The printing characteristic information acquisition unit 110 acquires printing characteristic information PCI and texture information TI related to the printed matter PM printed on the printing medium using the printing press 300. The printing characteristic information PCI includes a bleeding parameter ZP that indicates the bleeding state in the printed matter PM. In this embodiment, the printing characteristic information acquisition unit 110 acquires the printing characteristic information PCI and the texture information TI according to the printing conditions input by the user.

[0018] 4 is an explanatory diagram showing the printing condition setting screen PCW. The printing condition setting screen PCW includes a printing press selection tool ST1 for selecting the model of printing press 300 for actual printing, a medium selection tool ST2 for selecting the type of printing medium for actual printing, and a thumbnail image TItp of texture information TI. The printing characteristic information acquisition unit 110 acquires the printing characteristic information PCI and texture information TI in the following procedure. <Step 1> The printer model is obtained from the printer database 410 and displayed as a list in the printer selection tool ST1. At this time, it is preferable to obtain only printer models that can be used for actual printing. <Step 2> When a user selects a printing press using the printing press selection tool ST1, a list of print media that can be printed by the selected printing press is obtained from the print medium database 420 and displayed in the medium selection tool ST2. Alternatively, the user may be allowed to input any type of print medium. <Step 3> When the user selects one printing medium using the medium selection tool ST2, printing characteristic information PCI is obtained from the printing press database 410 according to the combination of the selected printing press and printing medium. <Step 4> Texture information TI of the selected printing medium is acquired, and a thumbnail image TItp thereof is displayed on the printing condition setting screen PCW.

[0019] The basic proof image acquisition unit 120 shown in FIG. 3 acquires basic proof image data BPF. The basic proof image data BPF is data that reflects the differences in color reproduction between the printing press 300 and the proof output device in the input image data IM. In other words, the basic proof image data BPF is data for reproducing the colors of the printout PM printed on the printing medium using the printing press 300 on the proof output device. However, the basic proof image data BPF does not reflect ink bleeding or texture information of the printing medium. In this embodiment, the basic proof image acquisition unit 120 creates basic proof image data BPF from the input image data IM. This creation process uses various ICC profiles, such as the input profile of the input image data IM, the device profile and media profile of the proof output device, and the media profile of the printing press 300 that will print the printout PM. However, if the basic proof image data BPF has already been created, the basic proof image acquisition unit 120 may acquire the basic proof image data BPF by reading it from the storage unit 60.

[0020] Any method can be used to create the basic proof image data BPF. For example, the method described in Japanese Patent Application No. 2022-194704, filed by the applicant of the present disclosure, may be used. In this method, the following processes are executed in sequence. <Process P1> The first image data is obtained by converting the color space of the input image data IM into the output color space of the printing machine 300 using an ICC profile. <Process P2> The first image data is converted to a representation in the profile connection space using a first conversion table, and white point conversion is performed using information on how the background color area in the printed matter PM, where no image is formed, appears in a predetermined observation environment, thereby obtaining second image data represented in the absolute XYZ color space. <Process P3> Using a second conversion table, the second image data is converted into converted image data expressed in the output color space of the proof output device. The output color space of the proof output device is, for example, the CMYK color space or the RGB color space. The second image data or the converted image data can be used as basic proof image data BPF.

[0021] Note that a proof image may also be created using the above-mentioned conventional technique (JP 09-270930 A) or the method described in JP 2006-30277 A. When using the above-mentioned conventional technique, basic proof image data BPF that does not reflect texture can be created by performing processing that omits the first and second corrections related to the texture of the paper.

[0022] In this embodiment, the basic proof image data BPF is assumed to be expressed in the L*a*b* color space. When basic proof image data expressed in the output color space of the proof output device is created using the various methods described above, the output color space of the proof output device can be converted to the L*a*b* color space using the output profile of the proof output device. Furthermore, when using the method described in the above-mentioned Japanese Patent Application No. 2022-194704, the color space of the second image data expressed in the absolute XYZ color space may be converted to the L*a*b* color space.

[0023] 5 is an explanatory diagram showing an example of a basic proof image represented by basic proof image data BPF. The basic proof image data BPF represents a basic proof image in which a dark-colored ink-discharged area IP is printed on a background BG. In this embodiment, the basic proof image data BPF is expressed in the L*a*b* color space. For example, the background BG is a white area with L*=90, and the ink-discharged area IP is a gray area with L*=25.

[0024] 3, the bleed processing unit 130 applies bleed processing to the basic proof image data BPF to create bleed-added proof image data ZPF that simulates a bleed state. The bleed processing unit 130 includes an edge extraction unit 131 and a bleed adding unit 132.

[0025] The edge extraction unit 131 generates edge data ED representing the edges by extracting edges of the basic proof image represented by the basic proof image data BPF. As the edge extraction process, for example, one or more of the following processes can be used.

[0026] <Edge extraction processing using pixel value differences> The brightness difference or color difference between adjacent pixels in the basic proof image is calculated, and pixels with a brightness difference or color difference greater than or equal to a threshold are extracted as edge pixels. In edge extraction processing using brightness difference, the difference in brightness L* between the basic proof image and a shifted image obtained by shifting the basic proof image by one pixel is calculated, and pixels with an absolute value of the brightness difference greater than or equal to a threshold are determined as candidate pixels. If the brightness difference is positive, the candidate pixel is extracted as an edge pixel. On the other hand, if the brightness difference is negative, a pixel shifted one pixel from the candidate pixel in the direction opposite to the shift direction is extracted as an edge pixel. This edge extraction processing is performed for both cases where pixels are shifted vertically and horizontally. The same is true for edge extraction processing using color difference.

[0027] <Edge extraction processing using an edge extraction filter> An edge extraction filter is used to extract edge pixels contained in the basic proof image.

[0028] <Edge extraction processing for characters> If the basic proof image data BPF includes character data representing characters, pixels that form the outline of the characters are extracted as edge pixels.

[0029] In the example of FIG. 5, all pixels that make up the dark-color ink ejection area IP are extracted as edge pixels.

[0030] The bleeding unit 132 shown in Fig. 3 applies a bleeding process to the basic proof image data BPF using printing characteristic information PCI including the bleeding parameter ZP to create bleeding proof image data ZPF that simulates a bleeding state. In addition to the bleeding parameter ZP, the bleeding process also references the edge data ED and texture information TI. An example of the bleeding process will be described later.

[0031] The texture imparting unit 140 applies a process for imparting the texture of the printing medium to the bleed-added proof image data ZPF obtained by the bleed-adding process using the texture information TI, thereby creating texture-imparted proof image data TPF that simulates the texture. The texture imparting process may be similar to the process disclosed in Japanese Patent Application Laid-Open No. 06-86045. Specifically, the difference between the average texture value and each texture value may be multiplied by a gain and the result may be added to the pixel value of the bleed-added proof image data ZPF. Texture imparting may also be performed according to other known methods. If the bleed-added proof image data ZPF is expressed in the CIE-L*a*b* color system, the texture imparting process may be performed only on the lightness L*. If the bleed-added proof image data ZPF is expressed in the RGB color system, the texture imparting process may be performed on each RGB color component.

[0032] FIG. 6 is an explanatory diagram showing an example of texture information TI. As texture information TI, a height map used in 3D rendering or a brightness value map generated based on image data obtained by photographing a print medium can be used. In either case, the texture information TI is preferably configured as a map of texture values ​​that indicate the unevenness of the print medium. In the example of FIG. 6, the texture value assigned to each pixel is brightness L*. Pixels with high brightness L* correspond to convex portions, and pixels with low brightness L* correspond to concave portions. However, values ​​in the range of 0 (dark) to 100 (light) may also be used as the texture value. The image area of ​​the texture information TI preferably has a size that encompasses the basic proof image.

[0033] 7 is an explanatory diagram showing an example of printing characteristic information PCI acquired by the printing characteristic information acquisition unit 110. Here, printing characteristic information PCI is illustrated for eight printing conditions. Each printing condition includes one of the following four types of printing presses. (1) Textile printing machine A textile printing press, also known as a DTF (Direct to Fabric) printing press, is a printing press that prints ink directly onto fabric. A characteristic of printed materials produced by a textile printing press is that the ink tends to bleed along the weave direction of the threads on the surface of the fabric. In other words, ink bleed tends to depend on the texture of the printing medium. The printing characteristic information PCI for textile printing presses A to C is information corresponding to the combination of a textile printing press and three different types of printing medium suitable for the textile printing press. (2)ST printing machine An ST (Sublimitation Transfer) printer uses dye sublimation to transfer ink from transfer paper to print media by using heat to sublimate the ink. In ST printers, ink transfer is less texture-dependent. In other words, ink bleeding tends to be independent of the texture of the print media. The printing characteristic information PCI for an ST printer is information about the combination of an ST printer and a specific print media suitable for the ST printer. (3)DTG printing machine DTG (Direct to Garment) printing machines print ink directly onto sewn fabrics, T-shirts, cloth bags, etc. As with textile printing machines, ink bleeding with DTG printing machines tends to depend on the texture of the printing medium. However, if a base layer is formed using white ink or the like under the print layer that forms the image, it tends to be less dependent on the texture. The printing characteristic information PCI for DTG printing machine A is information for when there is no base layer, and the printing characteristic information PCI for DTG printing machine B is information for when there is a base layer. (4) DTFilm printing machine A DTFilm (Direct to Film) printer is a transfer film printer that prints an image onto a transfer film and then transfers the image from the transfer film to a print medium such as fabric to create a printed matter PM. DTFilm printers tend to have even less texture dependency than ST printers. The printing characteristic information PCI for DTFilm printer A is information for when there is no base layer, and the printing characteristic information PCI for DTFilm printer B is information for when there is a base layer.

[0034] The printing characteristic information PCI includes the following parameters: <Base layer parameter UL> The underlayer parameter UL indicates whether or not a underlayer is formed using white ink or the like below the image printing layer, which forms the image with process ink. Because underlayers are often formed in DTG and DTFilm printers, examples of printing characteristic information PCI are provided for cases with and without underlayers. When a underlayer is present, the bleeding range ZR and bleeding intensity coefficient α tend to be smaller than when no underlayer is present.

[0035] <Texture dependent flag TF> The texture-dependent flag TF is a flag that indicates whether ink bleeding depends on the texture information TI of the printing medium. The bleeding process when texture dependency is present is called the "texture-dependent mode," and the bleeding process when texture dependency is not present is called the "texture-independent mode." In the texture-dependent mode, pixels whose texture values ​​in the texture information TI exceed a threshold value become candidates for bleeding.

[0036] <Smear range ZR> The blur range ZR indicates the range of pixels adjacent to an edge pixel that will become blur-target candidate pixels. For example, if the blur range ZR is one pixel, only one pixel adjacent to the edge pixel will become a blur-target candidate pixel. If the blur range ZR is two pixels, two pixels extending adjacent to the edge pixel will become blur-target candidate pixels. As will be described later, in the texture-dependent mode, pixels (blur-added candidates) among the blur-target candidate pixels will become blur-added pixels.

[0037] <Blurring strength coefficient α> The blur strength coefficient α is a coefficient that indicates the strength of blur in a blur-added pixel. The pixel value after the blur-adding process is determined according to the blur strength coefficient α. An example of how the blur strength coefficient α is used will be described later.

[0038] <Unevenness correction coefficient δ> The unevenness correction coefficient δ is a coefficient used to correct the texture information TI when the texture applying unit 140 performs the texture applying process. An example of how to use the unevenness correction coefficient δ will be described later.

[0039] Of the multiple parameters included in the printing characteristic information PCI, the texture-dependent flag TF, the bleeding range ZR, and the bleeding strength coefficient α correspond to the "bleeding parameter ZP" that represents the bleeding state in the printed matter PM.

[0040] 7, the printing characteristic information PCI is determined according to the combination of the printing press and the printing medium, but some of the parameters included in the printing characteristic information PCI may be determined according to only the printing press or only the printing medium. For example, the texture-dependent flag TF, the bleeding range ZR, and the bleeding strength coefficient α may be determined according to only the model of the printing press, and the unevenness correction coefficient δ may be determined according to only the type of printing medium.

[0041] 7 may be created for each model of printing press. In this case, multiple sets of printing property information PCI relating to multiple printing media are created for each printing press.

[0042] FIG. 8 is an explanatory diagram showing an example of the bleed application process in the texture-dependent mode. In this example, the bleed range ZR is one pixel. The bleed candidate pixel Z is a pixel adjacent to an edge pixel in the basic proof image and within a range of one pixel from the edge pixel. Because this is the texture-dependent mode, pixels in the texture information TI whose texture values ​​exceed a threshold are hatched as bleed application candidates. In the example in FIG. 8, the threshold is set to 90, which is the average value of the texture values ​​in the texture information TI. The reason for using the average value is that the range and distribution of texture values ​​in the texture information TI vary significantly depending on the printing medium, making the average value an appropriate threshold for determining the magnitude of the texture value. However, the user can set any threshold value, and it is preferable to set an appropriate threshold value based on the average texture value. In the bleed application process, bleed is applied to pixels among the bleed candidate pixel Z whose texture value exceeds the threshold. In the bleed-application proof image data ZPF, bleed-application pixels to which bleed has been applied are hatched.

[0043] The pixel value Lz after the blurring is added is determined, for example, according to the following formula. Lz = Le + (L*_white - Le) × (1.0 - α) = α×Le + (1.0 - α)×L*_white (q1) Here, Le is the basic proof pixel value of the edge pixel, L*_white is the basic proof pixel value of the background BG, and α is the bleeding intensity coefficient. The bleeding intensity coefficient α is a value greater than 0 and equal to or less than 1, and is included in the printing characteristic information PCI in FIG.

[0044] When the pixel value is lightness, the larger the blur strength coefficient α, the greater the degree of blur. In this embodiment, the basic proof pixel value is expressed as lightness, and the blur strength coefficient α is set to 1 or less. When the blur strength coefficient α is equal to 1.0, the pixel value Lz after blurring is added is a direct copy of the pixel value Le of the edge pixel. When the blur strength coefficient α is less than 1.0, the smaller the blur strength coefficient α, the closer the pixel value Lz after blurring is added to the pixel value L*_white of the background BG.

[0045] The pixel value Lz after the blurring is added may be determined according to the following formula instead of the above formula (q1). Lz = Le + (L0 - Le) × (1.0 - α) = α×Le + (1.0 - α)×L0 (q2) Here, L0 is the basic proof pixel value of the bleeding-added pixel before the bleeding-adding process. When this formula (q2) is used, if the bleeding strength coefficient α is less than 1.0, the pixel value Lz after the bleeding addition approaches the pixel value L0 before the bleeding addition as the bleeding strength coefficient α becomes smaller.

[0046] If the basic proof image data BPF is expressed in the CIE-L*a*b* color system, the bleeding process may be performed according to the above formula (q1) not only for the lightness L* but also for the a* and b* values. However, for the a* and b* values, it is preferable to copy the a* and b* values ​​of the edge pixels directly to the bleeding-to-be-given pixels. This makes it possible to reflect the color of the edge pixels in the bleeding-to-be-given pixels. Even if the basic proof image data BPF is expressed in another color system, the bleeding process may be performed according to the above formula (q1) or (q2) for the pixel values ​​of that color system.

[0047] FIG. 9 is an explanatory diagram showing another example of the blurring process in the texture-dependent mode. This example differs from the example of FIG. 8 only in that the blurring range ZR is two pixels. In this case, the blurring candidate pixel Z is a pixel adjacent to an edge pixel of the basic proof image and within a range of two pixels from the edge pixel. In the blurring process, blurring is applied to pixels among the blurring candidate pixel Z whose texture value exceeds a threshold. However, pixel NZP is a blurring candidate pixel Z and corresponds to a pixel whose texture value exceeds the threshold, but is excluded from the blurring application pixels. This is because the texture value of the pixel between pixel NZP and the edge pixel is equal to or less than the threshold. In this way, it is preferable that the blurring application pixels be selected so that they are continuous toward the outer periphery of the edge pixel.

[0048] Even when the blur range ZR is two or more pixels, the post-blur pixel value Lz can be calculated for all blur-added pixels according to the above formula (q1) or (q2). However, the blur strength coefficient α may be decreased as the pixel moves away from the edge pixel. Specifically, the blur strength coefficient α may be changed according to the following formula, for example: α = α0×{1.0 - De / (ZR + 1)} (q3) Here, α0 is the blur strength coefficient applied to blur-imparted pixels that are adjacent to an edge pixel, De is the distance from the edge pixel, and ZR is the blur range. The unit of the distance De from the edge pixel is [pixel], and the distance De of a blur-imparted pixel that is adjacent to an edge pixel is 1 pixel. For example, if the blur range ZR is 2 pixels, α = 2 / 3 × α0 for a pixel where De = 1, and α = 1 / 3 × α0 for a pixel where De = 2.

[0049] Instead of the above equation (q3), the blurring intensity coefficient α may be calculated according to the following equation: α = α0×(1.0 - β×De / (ZR+1)) (q4) Here, β is an adjustment value for adjusting the rate at which the bleeding intensity coefficient α is reduced according to the distance De from the edge pixel. β is set to a value greater than 0 and smaller than (ZR + 1)ZR. The bleeding intensity coefficient α may be expressed as a linear or curved decrease curve according to the distance from the edge pixel, according to an equation other than the above equations (q3) and (q4). The decrease curve of the bleeding intensity coefficient α may also be changed according to the combination of the printing machine and the printing medium.

[0050] FIG. 10 is an explanatory diagram showing an example of the bleeding processing in the texture-independent mode. In this example, the bleeding range ZR is one pixel. The bleeding target candidate pixel Z is a pixel that is adjacent to an edge pixel of the basic proof image and is within a range of one pixel from the edge pixel. In the bleeding processing in the texture-independent mode, bleeding is applied to all of the bleeding target candidate pixels Z. In the texture-independent mode, it is also possible to calculate the pixel value Lz after bleeding is applied using the same formula as in the texture-dependent mode.

[0051] FIG. 11 is an explanatory diagram showing differences in the bleeding processing depending on the printing characteristic information PCI. Here, the basic proof image data BPF and the texture information TI are simplified as each having a five-pixel region. In the texture information TI, the pixels PXH in the convex portions of the printing medium are not hatched, while the pixels PXL in the concave portions and the pixels PXM in the intermediate portions having an intermediate height are hatched. It is assumed that the texture values ​​of the pixels PXH in the convex portions and the pixels PXM in the intermediate portions are greater than a threshold, while the texture value of the pixels PXL in the concave portions is less than or equal to the threshold. In other words, in the texture-dependent mode, the pixels PXH in the convex portions and the pixels PXM in the intermediate portions are considered bleeding-imparting pixels, but the pixels PXL in the concave portions are not considered bleeding-imparting pixels.

[0052] The bottom of Figure 11 shows examples of bleed proof image data ZPF1 to ZPF5 created by the bleed application process for five of the eight printing conditions shown in Figure 7. It is assumed that the same basic proof image data BPF and texture information TI are applied to these bleed application processes. It can be seen that the bleed proof image data ZPF1 to ZPF5 have been bled by the bleed application process described with reference to Figures 8 to 10.

[0053] Fig. 12 is an explanatory diagram showing an example of texture-adding processing. This example shows a case where texture-adding processing is performed on the bleeding-added proof image data ZPF4 of the DTG printing machine A shown in Fig. 11, and texture-added proof image data TPF4 is created.

[0054] The texture application process is performed, for example, according to the following formula: Lt = Lz + γ×(Dti - Dti_ave) (q5) Here, Lt is the pixel value after texture is added, Lz is the pixel value of the bleeding proof image data, γ is the gain, Dti is the texture value, and Dti_ave is the average value of the texture values.

[0055] The texture imparting process according to the above formula (q5) is a process in which the difference between the average texture value Dti_ave and each texture value Dti is multiplied by a gain γ and the result is added to the pixel value Lz of the bleeding proof image data ZPF5. A positive value other than 0 is set as the gain γ. However, the texture imparting process may be performed using other calculation methods.

[0056] Figure 13 is an explanatory diagram showing the texture imparting process involving unevenness correction of texture information TI. This example shows the case where the texture imparting process is performed on the bleeding-imparted proof image data ZPF5 of DTG printing machine B shown in Figure 11. The texture information TI is corrected by the unevenness correction coefficient δ shown in Figure 7, and texture imparted proof image data TPF5 is created by the texture imparting process using the corrected texture information TIc.

[0057] The unevenness correction of the texture information TI is performed, for example, according to the following equation. Dti_c = Dti_0 + δ×(Dti_max - Dti_0) (q6) Here, Dti_c is the texture value after unevenness correction, Dti_0 is the texture value before unevenness correction, δ is the unevenness correction coefficient, and Dti_max is the maximum texture value in the texture information TI. The unevenness correction coefficient δ is included in the printing characteristic information PCI in Fig. 7 and is set to a value in the range of 0.0 to 1.0, for example.

[0058] When the unevenness correction coefficient δ is equal to 0.0, this is equivalent to not performing unevenness correction, and the texture information TI before correction is used as is to execute the texture imparting process. On the other hand, when the unevenness correction coefficient δ is equal to 1.0, the texture value Dti_c after unevenness correction is equal to the maximum texture value Dti_max. When the unevenness correction coefficient δ is set to a value greater than 0.0, a texture value with less unevenness than before unevenness correction is used to execute the texture imparting process. Furthermore, in this embodiment, since the texture value is expressed in lightness, the larger the unevenness correction coefficient δ, the larger the texture value Dti_c after unevenness correction, and the higher the lightness.

[0059] Because DTFilm printers print images on transfer film and then transfer them to the print medium, the texture of the print medium tends to be less apparent in the print PM. Furthermore, when forming a white base layer using a DTG printer, the white ink tends to fill in the fine irregularities of the print medium, making the texture less apparent in the print PM. Taking these points into consideration, the printing characteristic information PCI shown in Figure 7 sets the irregularity correction coefficient δ to a non-zero value for DTFilm printers A and B and DTG printer B. Similarly, the irregularity correction coefficient δ is set to a non-zero value for textile printer B. In these cases, the texture application process uses corrected texture information TIc, which has less irregularity than the original texture information TI. This allows proof image data to be created that more accurately simulates the effect of the texture on the print PM, even if the irregularities of the print medium's texture are less apparent.

[0060] FIG. 14 is a flowchart showing the steps of the proof image data creation process. In step S10, the printing characteristic information acquisition unit 110 receives printing conditions set by the user. This process is performed using, for example, the printing condition setting screen PCW shown in FIG. 4. In step S20, the printing characteristic information acquisition unit 110 acquires printing characteristic information PCI according to the printing conditions. At this time, texture information TI may also be acquired at the same time. In step S30, the basic proof image acquisition unit 120 acquires basic proof image data BPF. In step S40, the edge extraction unit 131 extracts edges of the basic proof image. In step S50, the bleed addition unit 132 performs bleed addition processing. In step S60, the texture addition unit 140 performs texture addition processing. The order of the steps in FIG. 14 may be changed as appropriate.

[0061] In the above embodiment, by applying a bleed-adding process to the basic proof image data BPF using the printing characteristic information PCI including the bleed parameter ZP that represents the bleed state in the printed matter PM, bleed-added proof image data ZPF that simulates the bleed state can be obtained. Also, by applying a texture-adding process to the bleed-added proof image data ZPF using the texture information TI, texture-added proof image data TPF that simulates the bleed state and texture can be obtained.

[0062] Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following forms. The technical features in the above embodiments corresponding to the technical features in each form described below can be appropriately replaced or combined 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 a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0063] (1) According to a first aspect of the present disclosure, there is provided a method for creating proof image data, the method including: (a) acquiring printing characteristic information for a printed matter to be printed on a printing medium using a printing press, the printing characteristic information including bleeding parameters that represent a bleeding state in the printed matter, (b) acquiring basic proof image data for reproducing the color of the printed matter using a proof output device, and (c) applying a bleeding process to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state. According to this method, proof image data that simulates the bleeding state can be obtained.

[0064] (2) In the above method, the step (a) may include a step of determining the printing characteristic information in accordance with a combination of the printing machine and the printing medium. According to this method, it is possible to simulate the bleeding state specific to a printing press by using printing characteristic information according to the combination of the printing press and the printing medium.

[0065] (3) The above method may further include (d) a step of creating textured proof image data that simulates the texture by applying a texture imparting process to the bleed proof image data using texture information that represents the texture of the printing medium. According to this method, it is possible to obtain textured proof image data that simulates the bleeding state and texture.

[0066] (4) In the above method, the texture information includes a texture value for each pixel; The printing characteristic information may include an unevenness correction coefficient for reducing unevenness in the texture value, and step (d) may include a step of creating corrected texture information in which the texture value is corrected with the unevenness correction coefficient, and a step of applying the texture imparting process to the bleeding proof image data using the corrected texture information. According to this method, it is possible to create proof image data that more accurately simulates the effect of texture on printed matter in which the unevenness of the texture of the printing medium is less likely to appear.

[0067] (5) In the above method, the bleeding parameters include a bleeding range parameter that defines a bleeding range, and the step (c) includes: (c1) a step of extracting an edge of the basic proof image represented by the basic proof image data; and (c2) a step of applying bleeding to pixel values ​​of the basic proof image data in a bleeding target area that is adjacent to the edge and extends over the bleeding range. It may also include. According to this method, the area to which bleeding is applied can be changed by adjusting the bleeding range parameter.

[0068] (6) In the above method, the bleeding process includes a texture-dependent mode that depends on the texture information, the texture information including a texture value for each pixel, and in the texture-dependent mode, the step (c2) includes a step of determining whether or not to apply the bleeding to each pixel in the bleeding target area in accordance with a magnitude relationship between the texture value and a threshold value, and a step of applying the bleeding to pixel values ​​of the basic proof image data for pixels in the bleeding target area that are determined to be applied with the bleeding. It may also include. According to this method, it is possible to determine whether or not to apply bleeding depending on the texture value.

[0069] (7) In the above method, the bleeding parameters may include a bleeding strength coefficient that defines the tendency of ink to bleed in the printed matter, and step (c) may include a step of determining a pixel value after the bleeding application process in accordance with the bleeding strength coefficient. This method makes it possible to simulate a bleeding state that reflects the ink's tendency to spread.

[0070] (8) In the above method, the blur strength coefficient may be set to decrease as the distance from the edge increases. This method makes it possible to simulate a bleeding state in which the influence of bleeding decreases the further away from the edge.

[0071] (9) According to a second aspect of the present disclosure, there is provided a proof image data creation device including: a printing characteristic information acquisition unit that acquires printing characteristic information, including bleeding parameters representing a bleeding state in a printed matter printed on a printing medium using a printing press, for the printed matter; a basic proof image acquisition unit that acquires basic proof image data for reproducing the color of the printed matter using a proof output device; and a bleeding processing unit that applies a bleeding process to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state.

[0072] (10) According to a third aspect of the present disclosure, there is provided a computer program for creating proof image data, which causes a computer to execute the following steps: (a) acquiring printing characteristic information for a printed matter to be printed on a printing medium using a printing press, the processing including bleeding parameters that represent a bleeding state in the printed matter; (b) acquiring basic proof image data for reproducing the color of the printed matter using a proof output device; and (c) applying a bleeding process to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state.

[0073] The present disclosure may be realized in various forms other than those described above, such as a computer program that realizes the functions of a proof image data creation device, or a non-transitory storage medium on which a computer program is recorded. [Explanation of symbols]

[0074] 50...CPU, 60...storage unit, 61...proof image creation program, 70...input / output interface, 100...proof image data creation device, 110...printing characteristic information acquisition unit, 120...basic proof image acquisition unit, 130...bleed processing unit, 131...edge extraction unit, 132...bleed application unit, 140...texture application unit, 150...display device, 200...proof printing device, 300...printing press, 400...cloud server, 410...printing press database, 420...printing medium database, 500...printing system

Claims

1. 1. A method for creating proof image data, comprising: (a) acquiring print characteristic information, including bleeding parameters representing bleeding conditions in a printed matter printed on a printing medium using a printing press; (b) acquiring basic proof image data for reproducing the colors of the printed matter with a proof output device; (c) applying a bleeding process to the basic proof image data using the printing characteristics information to create bleeding proof image data that simulates the bleeding state; A method comprising:

2. 10. The method of claim 1, The method, wherein step (a) includes determining the printing characteristic information according to a combination of the printing press and the printing medium.

3. 10. The method of claim 1 further comprising: (d) applying a texture imparting process to the bleed proof image data using texture information representing the texture of the printing medium, thereby creating texture imparted proof image data that simulates the texture; A method comprising:

4. 4. The method of claim 3, the texture information includes a texture value for each pixel; the printing characteristic information includes an unevenness correction coefficient for reducing unevenness in the texture value; The step (d) a step of generating corrected texture information by correcting the texture value with the unevenness correction coefficient; applying the texture imparting process to the bleed proof image data using the corrected texture information; A method comprising:

5. 4. The method of claim 3, the bleeding parameters include a bleeding range parameter that defines a bleeding range, The step (c) (c1) extracting edges of a basic proof image represented by the basic proof image data; (c2) applying bleeding to pixel values ​​of the basic proof image data in a bleeding target area adjacent to the edge and spanning the bleeding range; A method comprising:

6. 6. The method of claim 5, the bleeding process includes a texture-dependent mode that depends on the texture information, the texture information includes a texture value for each pixel; In the texture-dependent mode, step (c2) a step of determining whether or not to apply the blur for each pixel in the blur target region in accordance with the magnitude relationship between the texture value and a threshold value; a step of adding the bleeding to pixel values ​​of the basic proof image data for pixels in the bleeding target area that are determined to be added with the bleeding; A method comprising:

7. 6. The method of claim 5, the bleeding parameters include a bleeding intensity coefficient that defines the tendency of ink to bleed in the printed matter, The method, wherein the step (c) includes a step of determining a pixel value after the blurring processing in accordance with the blurring strength coefficient.

8. 8. The method of claim 7, A method wherein the blur strength coefficient is set to be smaller the further away from the edge.

9. A proof image data creation device, a printing characteristic information acquisition unit that acquires printing characteristic information including bleeding parameters that represent bleeding conditions in a printed matter printed on a printing medium using a printing machine; a basic proof image acquisition unit that acquires basic proof image data for reproducing the color of the printed matter by a proof output device; a bleeding processing unit that applies bleeding processing to the basic proof image data using the printing characteristic information to create bleeding-added proof image data that simulates the bleeding state; A proof image data creation device comprising:

10. A computer program for creating proof image data, (a) a process of acquiring print characteristic information including bleeding parameters that represent bleeding conditions in a printed matter printed on a printing medium using a printing machine; (b) acquiring basic proof image data for reproducing the colors of the printed matter on a proof output device; (c) applying a bleeding process to the basic proof image data using the printing characteristics information to create bleeding proof image data that simulates the bleeding state; A computer program that causes a computer to execute the following.

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