Image processing method, image processing device, printing system, and image processing program

Abstract

To provide a technique capable of better reflecting differences in texture of print media due to a difference in printing method, in a rendering image.SOLUTION: An image processing method includes the steps of: (a) acquiring print image data; (b) acquiring a printing method which is a method of forming a print image on a print medium; (c) setting a first texture parameter representing the texture of the print medium surface due to the presence of a print recording material, according to the print recording material amount which is the amount of a print recording material to be used to form the print image; (d) setting a second texture parameter representing the texture of the print medium itself; (e) setting a third texture parameter representing the texture of the print medium dependent on the printing method, according to the printing method; and (f) generating a rendering image of the print medium on which the print image is formed by rendering processing using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an image processing method, an image processing device, a printing system, and an image processing program. [Background technology]

[0002] Patent Document 1 discloses an image processing device that generates a 3D preview image of a printed matter based on a diffuse reflection image of a sample pattern formed on the printed matter, a differential image of the sample pattern, and information that is specified when forming the sample pattern and that affects the surface texture of the printed matter, all of which are recorded in a correspondence database. The information that affects the surface texture of the printed matter includes differences in printing methods. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-52483 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not specifically mention how differences in printing methods affect the surface texture of a printed material when generating a 3D preview image of the printed material. Therefore, there is a need for a technology that can better reflect differences in the texture of the print medium due to differences in printing methods in a rendering image of the print medium on which the print image is formed. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided an image processing method comprising the steps of: (a) acquiring print image data including pixel values ​​of a print image to be formed on a print medium; (b) acquiring a printing method for forming the print image on the print medium; (c) setting a first texture parameter representing the texture of the print medium surface due to the presence of the print recording material according to a print recording material amount representing the amount of the print recording material used to form the print image; (d) setting a second texture parameter representing the texture of the print medium itself; (e) setting a third texture parameter representing the texture of the print medium dependent on the printing method according to the printing method; and (f) generating a rendering image of the print medium on which the print image has been formed by rendering using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter.

[0006] According to a second aspect of the present disclosure, there is provided an image processing device comprising: an image data acquisition unit that acquires print image data including pixel values ​​of a print image to be formed on a print medium; a printing method acquisition unit that acquires a printing method that is a method of forming the print image on the print medium; a first texture setting unit that sets a first texture parameter that represents the texture of the print medium surface due to the presence of a print recording material in accordance with a print recording material amount that is the amount of the print recording material used to form the print image; a second texture setting unit that sets a second texture parameter that represents the texture of the print medium itself; a third texture setting unit that sets a third texture parameter that represents the texture of the print medium that depends on the printing method in accordance with the printing method; and a rendering unit that generates a rendering image of the print medium on which the print image is formed by rendering using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter.

[0007] According to a third aspect of the present disclosure, there is provided a printing system including the image processing device of the second aspect, a display device that displays the rendering image generated by the image processing device, and a printing device that prints the print image data on the printing medium.

[0008] According to a fourth aspect of the present disclosure, there is provided an image processing program that causes a computer to (a) acquire print image data including pixel values ​​of a print image to be formed on a print medium, (b) acquire a printing method that is a method for forming the print image on the print medium, (c) set a first texture parameter that represents the texture of the print medium surface due to the presence of the print recording material according to a print recording material amount that is the amount of the print recording material used to form the print image, (d) set a second texture parameter that represents the texture of the print medium itself, (e) set a third texture parameter that represents the texture of the print medium that depends on the printing method according to the printing method, and (f) generate a rendering image of the print medium on which the print image is formed by rendering processing using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram illustrating a schematic configuration of a printing system. [Figure 2] FIG. 1 is a block diagram showing a schematic configuration of an image processing device. [Figure 3] FIG. 2 is a block diagram showing the configuration of a rendering unit. [Figure 4] 10 is a flowchart of an image display process. [Figure 5] 10 is a flowchart of a color conversion process. [Figure 6] 10 is a flowchart of a first material texture parameter setting process. [Figure 7] 10 is a flowchart of a second material texture parameter setting process. [Figure 8] FIG. 10 is a diagram showing an example of a table associating printing methods with third texture parameters. [Figure 9] 10 is a flowchart of a saturation correction process. [Figure 10] 10 is a flowchart of a pixel color determination process. [Figure 11] FIG. 10 is a diagram showing an example of a still image constituting a video showing the movement of a print medium in a virtual space. [Figure 12] FIG. 10 is a diagram showing an example of a still image constituting a video showing the movement of a print medium in a virtual space. [Figure 13] 10A and 10B are diagrams illustrating examples of animations showing predetermined movements of print media in a virtual space. DETAILED DESCRIPTION OF THE INVENTION

[0010] A. First embodiment: FIG. 1 is a block diagram showing a schematic configuration of a printing system 10. The printing system 10 includes an image processing device 100, an input device 200, a display device 300, and a printing device 400. The image processing device 100 generates a rendering image representing a print medium on which a print image is formed using physics-based rendering, and displays the rendering image on the display device 300. In this embodiment, the print medium is a soft object such as cloth, paper, or a label. Hereinafter, physics-based rendering will be simply referred to as rendering.

[0011] The image processing device 100 is configured by a computer including a processor 101, a memory 102, an input / output interface 103, and an internal bus 104. The processor 101, the memory 102, and the input / output interface 103 are connected via the internal bus 104 to enable bidirectional communication. The input device 200, the display device 300, and the printing device 400 are connected to the input / output interface 103 of the image processing device 100 via wired or wireless communication. The input device 200 is, for example, a keyboard or a mouse, and the display device 300 is, for example, a liquid crystal display. The input device 200 and the display device 300 may be integrated as a touch panel. The printing device 400 is a device that prints an image on a printing medium, and is, for example, an inkjet printer, a dye sublimation printer, a direct to film (DTF) printer, a solvent printer, a proof printer, a screen printing machine, or a UV printer.

[0012] 2 is a block diagram showing a schematic configuration of the image processing device 100. The image processing device 100 includes an image data acquisition unit 105, a printing method acquisition unit 110, a printing condition acquisition unit 115, a color profile acquisition unit 120, a color management system 125, a rendering condition setting unit 130, a print recording material amount determination unit 135, a first texture setting unit 140, a second texture setting unit 145, a third texture setting unit 150, and a rendering unit 155. The image data acquisition unit 105, printing method acquisition unit 110, printing condition acquisition unit 115, color profile acquisition unit 120, color management system 125, rendering condition setting unit 130, print recording material amount determination unit 135, first texture setting unit 140, second texture setting unit 145, third texture setting unit 150, and rendering unit 155 are implemented as software by the processor 101 executing the image processing program PG pre-stored in memory 102. The color management system 125 is also referred to as a color conversion unit.

[0013] The image data acquisition unit 105 acquires print image data including pixel values ​​of a print image to be formed on a print medium. The print image data acquired by the image data acquisition unit 105 is sent to the color management system 125.

[0014] The printing method acquisition unit 110 acquires a printing method, which is a method for forming a print image on a print medium. Examples of printing methods include digital textile printing, dye sublimation transfer printing, Direct to Film (DTF) printing, and screen printing. The printing method acquired by the printing method acquisition unit 110 is sent to the third texture setting unit 150. The printing method may include document printing, photo printing, CD printing, proof printing, and the like.

[0015] The printing condition acquisition unit 115 acquires printing conditions. The printing conditions are conditions that affect the amount of print recording material used when forming an image on a printing medium. The printing conditions include the type of printing device 400, the type of printing medium, and the type of ink used for printing. The printing conditions acquired by the printing condition acquisition unit 115 are sent to the color profile acquisition unit 120, the color management system 125, the first texture setting unit 140, and the second texture setting unit 145.

[0016] The color profile acquisition unit 120 acquires an input profile, a media profile, and a common color space profile as color profiles used for color conversion by the color management system 125. The input profile is an ICC profile used for color conversion from the input color space used in the print image data to a device-independent color space. The input color space is, for example, an RGB color space. The device-independent color space is, for example, the CIE-L*a*b* color space or the CIE-XYZ color space. Hereinafter, the CIE-L*a*b* color space will be simply referred to as the Lab color space, and the CIE-XYZ color space will be simply referred to as the XYZ color space. The media profile is an ICC profile used for color conversion from the device-independent color space to a device-dependent color space for the printing device 400. The device-dependent color space for the printing device 400 is, for example, the CMYK color space or the RGB color space. Colors in the device-dependent color space for the printing device 400 are also referred to as "device colors." The common color space profile is an ICC profile used for color conversion from a device-independent color space to a rendering color space. The rendering color space is a color space for the display device 300, such as sRGB, Adobe (registered trademark) RGB, or Display-P3. The color profile acquisition unit 120 acquires color profiles pre-stored in the memory 102 according to the types of the printing device 400 and the display device 300. Each profile acquired by the color profile acquisition unit 120 is sent to the color management system 125. Note that the color profile acquisition unit 120 may also acquire color profiles from an external server via a network.

[0017] The color management system 125 uses each profile to perform color conversion on the print image data. The color conversion performed by the color management system 125 will be described in detail later.

[0018] The rendering condition setting unit 130 sets the conditions for rendering to be performed by the rendering unit 155. The rendering conditions include 3D object information, camera information, lighting information, background information, etc. The 3D object information is a parameter related to a 3D object to be placed in a virtual space. The 3D object is created in advance to simulate the shape of the print medium and is composed of multiple polygons. The camera information is a parameter related to the position and orientation of a camera placed in the virtual space. The lighting information is a parameter related to the type, position, orientation, color, and luminance of a light source placed in the virtual space. Examples of light source types include fluorescent lamps and incandescent bulbs. The background information is information related to the background in which the print medium as a 3D object is placed in the virtual space. The background information includes information about objects such as walls, floors, and furniture placed in the virtual space. These objects are the subject of rendering by the rendering unit 155 in the same way as the print medium.

[0019] The print recording material amount determination unit 135 determines the amount of print recording material used when forming a print image on a print medium. The print recording material amount is, for example, the amount of ink.

[0020] The first texture setting unit 140 sets a first texture parameter that represents the texture of the surface of the printing medium due to the presence of the print recording material. Examples of the first texture parameter include roughness, metallicity, and specular color. Roughness is a value that represents the roughness of the printing medium. The roughness value is specified, for example, in the range of 0 to 1. Note that instead of roughness, smoothness, which represents the smoothness of the printing medium, may be included. Metallicity is a value that represents the metallicity of the printing medium, i.e., the level of the specular reflection rate. The metallicity value is specified, for example, in the range of 0 to 1. Note that the value of the first texture parameter does not have to be specified in the range of 0 to 1, and may be specified, for example, in the range of 0 to 100.

[0021] The second texture setting unit 145 sets second texture parameters that represent the texture of the printing medium itself. Examples of second texture parameters include a normal map and a height map. Normal maps and height maps are used to represent the minute unevenness of the printing medium's surface, which affects light reflection. A normal map is a texture that represents the distribution of normal vectors of the minute unevenness, and a height map is a texture that represents the distribution of heights of the minute unevenness. Reducing the size of the polygons that make up a 3D object to represent the minute unevenness results in an enormous number of polygons, increasing the calculation load for rendering. By using a normal map or a height map, it is possible to represent the effect of the minute unevenness on light reflection without reducing the polygon size. The values ​​of the normal map and height map are specified, for example, in the range of 0 to 1. Other examples of second texture parameters include parameters that indicate the presence or absence of a clear coat layer on the surface of the printing medium, the thickness of the clear coat layer, and the transparency of the clear coat layer. The value of the second texture parameter does not have to be specified in the range of 0-1, but may be specified in the range of 0-100, for example.

[0022] The third texture setting unit 150 sets a third texture parameter that represents the texture of the print medium, which depends on the printing method. The third texture parameter includes a fourth texture parameter that represents the appearance of the print medium and a fifth texture parameter that represents the movement of the print medium. In this specification, the fourth texture parameter is also referred to as the "appearance texture parameter," and the fifth texture parameter is also referred to as the "movement texture parameter." The fourth texture parameter includes a correction value for the first texture parameter and a correction value for the second texture parameter.

[0023] The fourth texture parameters include a roughness correction value, a normal map correction value, saturation, and penetration. Saturation is a value that represents the vividness of the printed image. Penetration is a value that represents the penetration of the printing medium. Penetration represents, for example, the degree of ink penetration from the front surface to the back surface of the printing medium. The value of each fourth texture parameter is specified in the range of 0 to 1. Here, the higher the saturation value, the more vivid the printed image, and the higher the penetration value, the easier it is for ink to penetrate into the printing medium. Note that the value of the fourth texture parameter does not have to be specified in the range of 0 to 1, and may be specified in the range of 0 to 100, for example.

[0024] The fifth texture parameters include mass, bend, stretch, and friction. Mass is a value that represents the weight of the print medium. Bendability is a value that represents how easily the print medium bends. Stretchability is a value that represents how easily the print medium stretches. Friction is a value that represents the degree of friction between the print medium and other objects. The value of each fifth texture parameter is specified in the range of 0 to 1. Here, the larger the weight value, the heavier the print medium is; the larger the bendability value, the harder the print medium is to bend; the larger the stretchability value, the more easily the print medium stretches; and the larger the friction value, the greater the friction between the print medium and other objects. Note that the value of the fifth texture parameter does not have to be specified in the range of 0 to 1, and may be specified in the range of 0 to 100, for example.

[0025] The rendering unit 155 generates a rendering image representing the printing medium on which the printing image is formed by performing rendering using the printing image data, the first texture parameter, the second texture parameter, and the third texture parameter.

[0026] 3 is a block diagram showing the configuration of the rendering unit 155. The rendering unit 155 includes a vertex pipeline VPL, a rasterizer RRZ, a pixel pipeline PPL, and a post-processing unit PST. In this embodiment, the vertex pipeline VPL includes a vertex shader VS and a geometry shader GS, and the pixel pipeline PPL includes a pixel shader PS and a render backend RBE.

[0027] The vertex shader VS uses 3D object information, camera information, and lighting information to perform coordinate transformation of the vertices of each polygon that makes up the 3D object, calculation of the normal vectors of each polygon, shading, and calculation of texture mapping coordinates. Coordinate transformations include model transformation, which is a coordinate transformation from the local coordinate system, which is the coordinate system of the 3D object, to the world coordinate system, which is the coordinate system of the virtual space; view transformation, which is a coordinate transformation from the world coordinate system to the view coordinate system, which is the coordinate system of the camera placed in the virtual space; and projection transformation, which is a coordinate transformation from the view coordinate system to the screen coordinate system, which is the coordinate system of the screen onto which the scene viewed from the camera is projected. Some of the above coordinate transformations may be performed by the geometry shader GS. The processing results of the vertex shader VS are sent to the geometry shader GS. Texture mapping coordinates are also called UV coordinates, the local coordinate system is also called the model coordinate system, the world coordinate system is also called the global coordinate system, the view coordinate system is also called the camera coordinate system, and the screen coordinate system is also called the clipping coordinate system.

[0028] The geometry shader GS processes a set of vertices of a 3D object. The geometry shader GS can convert polygons into points or lines, or convert points or lines into polygons, by increasing or decreasing the number of vertices. The processing results of the geometry shader GS are sent to the rasterizer RRZ. Note that in other embodiments, the rendering unit 155 may not be provided with a geometry shader GS. In this case, the processing results of the vertex shader VS are sent to the rasterizer RRZ.

[0029] The rasterizer RRZ performs rasterization processing to generate drawing information for each pixel from the processing results of the vertex pipeline VPL. The processing results of the rasterizer RRZ are sent to the pixel shader PS.

[0030] The pixel shader PS calculates the color of each pixel by performing lighting processing using the rasterized 3D object, print image data, and the first, second, and third texture parameters. The Disney Principled BRDF, for example, can be used as a function to calculate the reflection of light during lighting processing. The processing results of the pixel shader PS are sent to the render backend RBE.

[0031] The render backend RBE determines whether or not to write pixel data generated by the pixel shader PS to a display area in the memory 102. If the render backend RBE determines to write to the memory 102, the pixel data is saved as a drawing target, and if the render backend RBE does not determine to write to the memory 102, the pixel data is not saved as a drawing target. To determine whether or not to write, for example, an alpha test, a depth test, a stencil test, or the like is used.

[0032] The post-processing unit PST performs post-processing such as anti-aliasing, ambient occlusion, screen space reflection, and depth of field processing on the rendered image made up of pixel data stored in memory 102, thereby improving the appearance of the rendered image.

[0033] 4 is a flowchart of the image display process. The image display process is a process for generating a rendering image representing the print medium on which the print image is printed, and displaying the generated rendering image on the display device 300.

[0034] In step S10, the image data acquisition unit 105 acquires print image data. The print image data is input to the image processing device 100 by, for example, a user.

[0035] In step S20, the printing method acquisition unit 110 acquires a printing method, such as the printing method designated by the user for the printing device 400 that will print the print image data.

[0036] In step S30, the printing condition acquisition unit 115 acquires the printing conditions designated by the user.

[0037] In step S40, the color management system 125 executes color conversion processing, which converts the print image data into color data in a common color space for rendering processing.

[0038] 5 is a flowchart of the color conversion process. First, in step S210, the color management system 125 performs a first color conversion on the print image data from the input color space to the device-independent color space using the input profile.

[0039] In step S220, the color management system 125 performs a second color conversion on the print image data, using a media profile corresponding to the printing conditions, from the device-independent color space to the device-dependent color space for the printing device. The print image data that has undergone the first and second color conversions is called "device color image data." The device color image data is output to the first texture setting unit 140.

[0040] In step S230, the color management system 125 performs a third color conversion on the print image data from the device-dependent color space for the printing device to the device-independent color space using a media profile corresponding to the printing conditions.

[0041] In step S240, the color management system 125 performs a fourth color conversion on the print image data, from the device-independent color space to the rendering color space, using a common color space profile. The print image data that has undergone the four color conversions, from the first color conversion to the fourth color conversion, is called "managed image data." The managed image data is output to the rendering unit 155. The color conversion process is performed as described above.

[0042] In step S50 of FIG. 4, the print recording material amount determination unit 135 determines the print recording material amount using the device color image data and printing conditions. Specifically, the print recording material amount determination unit 135 determines the ink amount for each pixel. The ink amount for each pixel may be the ink amount for each color ink ejected on that pixel, the total amount of all ink droplets, or the ink amount for a specific color. The ink amount here may also be digital data representing the ink ejection amount. For example, this digital data may be on / off data for dots on each recording material. In this embodiment, the printing device 400 ejects inks related to printing the print image, such as a CMY ink set, a color ink set such as CMYLcLm including light cyan Lc and light magenta Lm, a CMYK multicolor ink set including black, or monochrome ink. The monochrome ink may be an ink set including not only black ink but also gray ink.

[0043] In step S60, a first texture parameter setting process is executed, which sets a first texture parameter based on the print recording material amount determined in step S50.

[0044] 6 is a flowchart of the first texture parameter setting process. First, in step S310, the first texture setting unit 140 acquires device color image data.

[0045] In step S320, the first texture setting unit 140 acquires the printing conditions.

[0046] In step S330, the first texture setting unit 140 sets initial values ​​S1 and S2 of the first texture parameters. Here, roughness will be used as an example of the first texture parameter. The first texture setting unit 140 sets the initial values ​​S1 and S2 of roughness to be set for the printing medium based on the type of printing medium included in the printing conditions. The initial value S1 indicates the smoothness of the portion of the printing medium where ink has not been ejected, and the initial value S2 indicates the smoothness of the portion of the printing medium where ink has been ejected. Generally, if the printing medium is a non-glossy fabric such as cotton, the initial roughness value S1 is set high, and if the printing medium is a glossy fabric such as silk, the initial value S2 is set low. Furthermore, the initial value S2 is set to a value higher than the initial value S1. In this embodiment, the initial roughness values ​​S1 and S2 are set to, for example, S1 = 0.85 and S2 = 0.95 for cotton. Furthermore, for example, S1 = 0.05 and S2 = 0.1 for silk. Here, roughness is taken as the first texture parameter, but other parameters may be used, or multiple parameters may be set.

[0047] Next, the first texture setting unit 140 repeats the processes of steps S340 to S370 for all pixels of the device color image data. The order in which the processes are performed on the pixels may be any order, and for example, the upper left corner of the printing medium may be set as the origin and the pixels may be read out along the width direction of the printing medium to the edge, and this may be repeated sequentially along the length direction of the printing medium until the lower right corner of the printing medium is reached.

[0048] In step S340, the first texture setting unit 140 reads the amount of ink to be ejected for printing the print image from the pixel value of one pixel.

[0049] In step S350, the first texture setting unit 140 determines whether the pixel is paper white, i.e., whether the sum of the ink ejection amounts for the pixel is zero. If the pixel is paper white, step S360a is executed. If the pixel is not paper white, step S360b is executed. Note that step S360a may be executed if the sum of the ink ejection amounts for the pixel is less than a predetermined lower limit, and step S360b may be executed if the sum of the ink ejection amounts for the pixel is equal to or greater than the lower limit.

[0050] In step S360a, the first texture setting unit 140 sets the roughness correction value S to an initial value S1. In step S360b, the first texture setting unit 140 sets the roughness correction value S to an initial value S2. In this embodiment, when the printing medium is cotton, S1 = 0.85 and S2 = 0.95 are set, so the roughness of the pixels in the paper-white area is set to the initial value S1, i.e., a value of 0.85. The roughness of the pixels onto which image formation ink is ejected is set to the initial value S2, i.e., a value of 0.95.

[0051] In step S370, the first texture setting unit 140 stores the roughness correction value S in the memory 102.

[0052] In step S380, the first texture setting unit 140 determines whether or not a roughness correction value S has been set for all pixels of the device color image data. If a roughness correction value S has been set for all pixels, step S390 is executed. If a roughness correction value S has not been set for all pixels, the process returns to step S340.

[0053] In step S390, the first texture setting section 140 outputs the roughness correction value S as the first texture parameter to the third texture setting section 150. The first texture parameter setting process is executed as described above.

[0054] A second texture parameter setting process is executed in step S70 of Fig. 4. The second texture parameter setting process is a process for setting a second texture parameter.

[0055] 7 is a flowchart of the second texture parameter setting process. First, in step S410, the second texture setting unit 145 acquires the printing conditions.

[0056] In step S420, the second texture setting unit 145 acquires a normal map of the printing medium corresponding to the type of printing medium included in the printing conditions acquired in step S410. Here, a normal map is taken as the second texture parameter, but other parameters may be used, or multiple parameters may be acquired.

[0057] In step S430, second material texture setting section 145 outputs the normal map acquired in step S420 as a second material texture parameter to third material texture setting section 150. The second material texture parameter setting process is executed as described above.

[0058] In step S80 of FIG. 4, the third texture setting unit 150 sets the third texture parameters using a table that is stored in advance in the memory 102 and that associates printing methods with third texture parameters.

[0059] FIG. 8 is a diagram showing an example of a table associating printing methods with third texture parameters. In FIG. 8, the printing methods shown are dye sublimation printing, digital textile printing, and DTF printing, and the third texture parameters shown are a roughness correction value, a normal map correction value, a saturation correction value, permeability, mass, bend, stretch, and friction. The third texture setting unit 150 obtains a value corresponding to the printing method obtained by the printing method obtaining unit 110 in step S20 from the table and sets it as the value of the third texture parameter. Hereinafter, the table shown in FIG. 8 is also referred to as a printing method-dependent texture table. In this embodiment, the third texture setting unit 150 outputs the values ​​of permeability, mass, bend, stretch, and friction to the pixel shader PS as the third texture parameters.

[0060] 4, the third texture setting unit 150 corrects the first texture parameter and the second texture parameter using the fourth texture parameter. In this embodiment, the third texture setting unit 150 corrects the roughness value, which is the first texture parameter, using the roughness correction value, which is the fourth texture parameter, and corrects the normal map value, which is the second texture parameter, using the normal map correction value, which is the fourth texture parameter.

[0061] The roughness value, which is the first texture parameter, is corrected using the following equation (1). In equation (1), R is the roughness value set in the first texture parameter setting process, Max_R is the maximum roughness correction value, and a is the roughness correction value set in step S80. In this embodiment, R is the roughness correction value S, and Max_R is 1. For example, when the printing method is dye sublimation transfer printing, a is 0.1 according to the printing method-dependent texture table. New_R is the roughness value after correction. The third texture setting unit 150 outputs New_R to the pixel shader PS as the first texture parameter. New_R=R+Max_R×a (1)

[0062] The normal map value, which is the second texture parameter, is corrected using the following equation (2). In equation (2), N is the normal map value set in the second texture parameter setting process, and b is the normal map correction value set in step S80. For example, if the printing method is dye-sublimation printing, b is 0.05 according to the printing method-dependent texture table. New_N is the normal map value after correction. The third texture setting unit 150 outputs New_N to the pixel shader PS as the second texture parameter. New_N=N+b (2) Furthermore, the third material texture setting unit 150 outputs the values ​​of the first material texture parameter and the second material texture parameter that were not corrected in step S90 to the pixel shader PS.

[0063] In step S100, the third texture setting unit 150 corrects the saturation C of the print image using the correction value for saturation C set in step S80.

[0064] 9 is a flowchart of the saturation correction process. In the following description, the input color space is assumed to be the RGB color space. First, in step S510, the color management system 125 performs color conversion from the RGB color space to the Lab color space using the input profile for the print image data. At this time, the color management system 125 performs color conversion from the RGB color space to the XYZ color space, and then performs color conversion from the XYZ color space to the Lab color space. Note that the color management system 125 may also perform color conversion directly from the RGB color space to the Lab color space.

[0065] In step S520, the color management system 125 performs color conversion on the print image data from the Lab color space to the CIE-L*C*h* color space, which will be referred to below simply as the LCh color space.

[0066] In step S530, the third texture setting unit 150 corrects the value of saturation C in the LCh color space of the print image data. The value of saturation C is corrected using the following equation (3). In equation (3), C is the value of saturation C in the LCh color space of the print image data, and x is the correction value of saturation set in step S80. For example, if the printing method is digital textile printing, x is 0.8 according to the printing method-dependent texture table. New_C is the value of saturation C after correction. New_C=C×x (3)

[0067] In step S540, the color management system 125 performs color conversion from the LCh color space to the Lab color space on the print image data.

[0068] In step S550, the color management system 125 performs color conversion on the print image data from the Lab color space to the RGB color space using the input profile. At this time, the color management system 125 performs color conversion from the Lab color space to the XYZ color space, and then performs color conversion from the XYZ color space to the RGB color space. The color management system 125 may also perform color conversion directly from the Lab color space to the RGB color space. The saturation correction process is performed as described above. In the above description, color space conversion is performed on the print image data, and the saturation C value in the LCh color space is corrected. However, the RGB values ​​of the print image data may also be corrected individually.

[0069] 4, the rendering unit 155 executes rendering processing, which includes steps S111 and S112.

[0070] In step S111, pixel shader PS executes pixel color determination processing. In the pixel color determination processing, the pixel color of the pixel of the rendering image is determined using the penetration level set in step S80. In the following explanation, it is assumed that the texture of the front and back surfaces of the print medium is the same, the print image is printed only on the front surface of the print medium, and a pre-printed image is formed on the back surface of the print medium before printing.

[0071] 10 is a flowchart of the pixel color determination process. First, in step S610, the pixel shader PS uses the normal vector of the polygon calculated in the vertex pipeline VPL to determine whether the portion to be determined for the pixel color is the surface of the polygon. If it is determined that the portion to be determined is the surface of the polygon, step S620 is executed. If it is not determined that the portion to be determined is the surface of the polygon, step S630 is executed.

[0072] In step S620, the pixel shader PS obtains surface resource data for surface rendering, including the pixel value of the managed image data corresponding to the target portion, the first texture parameter corrected using the fourth texture parameter, and the second texture parameter corrected using the fourth texture parameter.

[0073] In step S630, the pixel shader PS obtains back surface resource data for back surface rendering. The back surface resource data includes the pixel value of the back surface image data, the penetration rate, the first texture parameter after being corrected using the fourth texture parameter, and the second texture parameter after being corrected using the fourth texture parameter. The back surface image data is the original image data of the existing back surface image.

[0074] In step S635, the pixel shader PS calculates the pixel value of the determination target portion using the following equation (4), taking into account the effect of bleed-through of the print image on the front side onto the back side. The pixel shader PS calculates the pixel values ​​for each of R, G, and B. Pixel value for back surface drawing = Pixel value of back surface image data × (1 - penetration rate) (4)

[0075] In step S640, the pixel shader PS performs lighting processing by taking into account the influence of the first texture parameter and the second texture parameter on the determination target portion, determines the pixel color of the pixel of the rendering image, and ends this processing. The pixel shader PS repeats the pixel color determination processing until the pixel colors of all pixels of the rendering image have been determined.

[0076] In step S112 of FIG. 4, the rendering unit 155 generates a rendering image of the print medium on which the print image is formed by performing rendering using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter. The rendering unit 155 generates a moving image representing the movement of the print medium in virtual space as a rendering image. Specifically, the rendering unit 155 generates a moving image representing the movement of the print medium in virtual space in response to user operations and an animation representing a predetermined movement of the print medium in virtual space as a rendering image. Here, the predetermined movement of the print medium in virtual space is, for example, the movement of the print medium fluttering in the wind or the movement of the print medium falling. The above-mentioned moving image is composed of multiple consecutive still images of the print medium existing in virtual space. The rendering unit 155 generates the moving image by performing rendering using the first texture parameter, the second texture parameter, the fourth texture parameter, and the fifth texture parameter. The fourth texture parameter is used to express the texture of the print medium in each still image. The fifth material parameter is used to express the movement of the print medium in the video. Here, the fifth material parameter is used as a parameter for cloth simulation, which physically simulates the movement of cloth, etc.

[0077] In step S120, the image processing device 100 displays the rendering image generated in step S112 on the display device 300. The image processing device 100 may display on the display device 300 both a moving image representing the movement of the print medium in the virtual space in response to the user's operation and an animation representing a predetermined movement of the print medium in the virtual space, or may display only one of them specified by the user on the display device 300.

[0078] FIG. 11 is a diagram illustrating an example of a still image constituting a moving image depicting the movement of a print medium in a virtual space. The still image shown in FIG. 11 displays a print medium PLb as a 3D object placed in the virtual space, a light source LG, and a background object Bob, such as furniture, that exists as part of the background. With the still image shown in FIG. 11 displayed on the display device 300, the user can operate the input device 200 to move the print medium PLb in the virtual space. For example, the user can rotate, move, pull, or pinch the print medium PLb in the virtual space. When the user moves the print medium PLb in the virtual space, the rendering unit 155 performs a rendering process each time and generates a still image as a rendering image that constitutes a moving image depicting the movement of the print medium PLb in response to the user's operation. The still image generated by the rendering unit 155 is displayed on the display device 300. The still image displayed on the display device 300 is updated each time the rendering unit 155 performs a rendering process. As a result, a moving image composed of multiple still images generated by the rendering unit 155 is displayed on the display device 300. Fig. 12 shows an example of a still image that constitutes a moving image showing the movement of the print medium PLb in response to a user operation. In the example shown in Fig. 12, the position of the print medium PLb has been changed from the still image shown in Fig. 11.

[0079] FIG. 13 is a diagram showing an example of an animation depicting the movement of a predetermined print medium in a virtual space. FIG. 13 shows the movement of the print medium when a piece of cloth, which is the print medium, is dropped onto a box. The value of the fifth texture parameter is different between the animation image shown in the upper row of FIG. 13 and the animation image shown in the lower row. As shown in FIG. 13, when the weight and bendability of the print medium, which are the fifth texture parameters, differ, differences arise in the way the cloth, which is the print medium, spreads when dropped onto a box, and this is reproduced in the rendering image. The image display process is executed as described above.

[0080] The texture of the print medium on which the print image is formed varies depending on the printing method. For example, in digital textile printing, ink penetrates the print medium more easily than in dye-sublimation printing and DTF printing. Furthermore, dye-sublimation printing and DTF printing produce print images with more vivid colors than digital textile printing. According to the first embodiment, the third texture setting unit 150 sets third texture parameters that represent the texture of the print medium, which is dependent on the printing method, and the rendering unit 155 uses the third texture parameters to generate a rendering image of the print medium on which the print image is formed. As a result, the rendering image of the print medium on which the print image is formed can better reflect the differences in the texture of the print medium due to the differences in the printing method.

[0081] Furthermore, in this embodiment, the printing condition acquisition unit 115 acquires printing conditions that affect the amount of print recording material used when forming an image on the print medium, and the print recording material amount determination unit 135 determines the amount of print recording material using the print image data and the printing conditions. Furthermore, the first texture parameter is determined according to the amount of print recording material. This improves the accuracy with which the texture of the print medium surface is represented in a rendering image of the print medium on which the print image is formed.

[0082] Furthermore, in this embodiment, the first texture setting unit 140 sets a first texture parameter for each pixel that constitutes the print image, which improves the accuracy of expressing the texture of the print medium in a rendering image of the print medium on which the print image is formed.

[0083] In this embodiment, the third texture setting unit 150 sets the third texture parameters using a table that associates printing methods with third texture parameters. Therefore, the third texture parameters can be set by storing the above-mentioned table in the memory 102 in advance.

[0084] In this embodiment, the third texture parameter includes a fourth texture parameter that represents the appearance of the print medium and a fifth texture parameter that represents the movement of the print medium, so that the appearance and movement of the print medium can be better reflected in the rendered image of the print medium on which the print image is formed.

[0085] In this embodiment, the fourth texture parameter includes a correction value for the first texture parameter and a correction value for the second texture parameter, and the image processing device 100 corrects the first texture parameter and the second texture parameter using the fourth texture parameter. This allows the rendering image of the printing medium on which the printed image is formed to better reflect differences in the texture of the printing medium due to differences in printing method.

[0086] In this embodiment, the rendering unit 155 uses the fifth texture parameter to generate a video representing the movement of the printing medium on which the print image is formed as a rendering image, allowing the user to confirm the movement of the printing medium on which the print image is formed.

[0087] Furthermore, in this embodiment, a rendering image of the print medium on which the print image is formed is displayed on the display device 300. Therefore, the user can check the rendering image of the print medium on which the print image is formed by the printing device 400.

[0088] B. Other Embodiments: (B-1) In the above embodiment, the print recording material amount determination unit 135 determines the print recording material amount using the print image data and the printing conditions. However, the print recording material amount determination unit 135 may determine the print recording material amount without using the printing conditions.

[0089] (B-2) In the above embodiment, the first texture setting unit 140 sets the first texture parameter for each pixel that makes up the print image. In contrast, the first texture setting unit 140 does not have to set the first texture parameter for each pixel that makes up the print image. The first texture setting unit 140 may, for example, set the first texture parameter for each of multiple pixels that make up the print image.

[0090] (B-3) In the above embodiment, the third texture setting unit 150 sets the third texture parameter using a table that associates printing methods with third texture parameters. However, the third texture setting unit 150 may set the third texture parameter without using the above-mentioned table. For example, the third texture setting unit 150 may set a value input by the user via the input device 200 as the third texture parameter.

[0091] (B-4) In the above embodiment, the third texture parameter includes the fourth texture parameter and the fifth texture parameter. In contrast, the third texture parameter may include at least one of the fourth texture parameter and the fifth texture parameter.

[0092] (B-5) In the above embodiment, the fourth texture parameter includes a correction value for the first texture parameter and a correction value for the second texture parameter. In contrast, the fourth texture parameter may include at least one of the correction value for the first texture parameter and the correction value for the second texture parameter.

[0093] (B-6) In the above embodiment, the rendering unit 155 generates a moving image representing the movement of the print medium in the virtual space as a rendering image. Alternatively, the rendering unit 155 may generate a still image of the print medium existing in the virtual space as a rendering image.

[0094] (B-7) In the above embodiment, the print medium is a soft object such as cloth, paper, label, etc. In contrast, the print medium may be a hard object such as an acrylic block, a mug, or wood on which a printed image can be formed by dye sublimation printing, DTF printing, or UV printing.

[0095] C. 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.

[0096] (1) According to a first aspect of the present disclosure, there is provided an image processing method comprising: (a) acquiring print image data including pixel values ​​of a print image to be formed on a print medium; (b) acquiring a printing method for forming the print image on the print medium; (c) setting a first texture parameter representing the texture of the print medium surface due to the presence of the print recording material according to a print recording material amount representing the amount of the print recording material used to form the print image; (d) setting a second texture parameter representing the texture of the print medium itself; (e) setting a third texture parameter representing the texture of the print medium dependent on the printing method according to the printing method; and (f) generating a rendering image of the print medium on which the print image has been formed by rendering using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter. According to this aspect, the difference in texture of the print medium due to the difference in printing method can be better reflected in the rendering image of the print medium on which the print image is formed.

[0097] (2) In the above embodiment, the method may further include: (g) acquiring printing conditions that affect the amount of print recording material used when forming an image on the print medium; and (h) determining the amount of print recording material using the print image data and the printing conditions. According to this aspect, it is possible to improve the accuracy of expressing the texture of the surface of the printing medium in a rendering image of the printing medium on which the print image is formed.

[0098] (3) In the above aspect, in the step (c), the first texture parameter may be set for each pixel that constitutes the print image. According to this aspect, it is possible to improve the accuracy of expressing the texture of the print medium in a rendering image of the print medium on which the print image is formed.

[0099] (4) In the above aspect, in the step (e), the third texture parameter may be set using a table that associates the printing method with the third texture parameter. According to this embodiment, the third material appearance parameter can be easily set.

[0100] (5) In the above aspect, the third texture parameter may include at least one of a fourth texture parameter representing the appearance of the print medium and a fifth texture parameter representing the movement of the print medium. According to this aspect, the appearance and movement of the print medium can be better reflected in the rendered image of the print medium on which the print image is formed.

[0101] (6) In the above embodiment, the third texture parameter may include the fourth texture parameter, and the fourth texture parameter may include a correction value of the first texture parameter or a correction value of the second texture parameter, and the method may further include (i) correcting the first texture parameter or the second texture parameter using the fourth texture parameter. According to this aspect, the difference in texture of the print medium due to the difference in printing method can be better reflected in the rendering image of the print medium on which the print image is formed.

[0102] (7) In the above embodiment, the third texture parameter may include the fifth texture parameter, and in step (f), the rendering image may be generated using the fifth texture parameter, and the rendering image may be a moving image representing the movement of the printing medium. According to this aspect, the user can check the movement of the printing medium on which the print image is formed.

[0103] (8) According to a second aspect of the present disclosure, there is provided an image processing device comprising: an image data acquisition unit that acquires print image data including pixel values ​​of a print image to be formed on a print medium; a printing method acquisition unit that acquires a printing method that is a method of forming the print image on the print medium; a first texture setting unit that sets a first texture parameter that represents the texture of the print medium surface due to the presence of a print recording material in accordance with a print recording material amount that is the amount of the print recording material used to form the print image; a second texture setting unit that sets a second texture parameter that represents the texture of the print medium itself; a third texture setting unit that sets a third texture parameter that represents the texture of the print medium that depends on the printing method in accordance with the printing method; and a rendering unit that generates a rendering image of the print medium on which the print image is formed by rendering processing using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter.

[0104] (9) According to a third aspect of the present disclosure, there is provided a printing system including the image processing device of the second aspect, a display device that displays the rendering image generated by the image processing device, and a printing device that prints the print image data on the printing medium. According to this aspect, the user can check a rendering image of the print medium on which the print image is formed by the printing device.

[0105] (10) According to a fourth aspect of the present disclosure, there is provided an image processing program that causes a computer to (a) acquire print image data including pixel values ​​of a print image to be formed on a print medium, (b) acquire a printing method that is a method for forming the print image on the print medium, (c) set a first texture parameter that represents the texture of the print medium surface due to the presence of the print recording material in accordance with a print recording material amount that is the amount of the print recording material used to form the print image, (d) set a second texture parameter that represents the texture of the print medium itself, (e) set a third texture parameter that represents the texture of the print medium that depends on the printing method in accordance with the printing method, and (f) generate a rendering image of the print medium on which the print image is formed by rendering processing using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter. [Explanation of symbols]

[0106] 10...printing system, 100...image processing device, 101...processor, 102...memory, 103...input / output interface, 104...internal bus, 105...image data acquisition unit, 110...printing method acquisition unit, 115...printing condition acquisition unit, 120...color profile acquisition unit, 125...color management system, 130...rendering condition setting unit, 135...print recording material amount determination unit, 140...first texture setting unit, 145...second texture setting unit, 150...third texture setting unit, 155...rendering unit, 200...input device, 300...display device, 400...printing device, Bob...background object, GS...geometry shader, LG...light source, PG...image processing program, PLb...printing medium, PPL...pixel pipeline, PS...pixel shader, PST...post-processing unit, RBE...render backend, RRZ...rasterizer, VPL...vertex pipeline, VS...vertex shader

Claims

1. 1. An image processing method, comprising: (a) acquiring print image data including pixel values ​​of a print image to be formed on a print medium; (b) acquiring a printing method for forming the print image on the print medium; (c) setting a first texture parameter representing the texture of the surface of the printing medium due to the presence of the print recording material in accordance with the amount of print recording material used to form the print image; (d) setting a second texture parameter representing the texture of the printing medium itself; (e) setting a third texture parameter representing a texture of the printing medium that depends on the printing method according to the printing method; (f) generating a rendering image of the printing medium on which the printing image is formed by a rendering process using the printing image data, the first texture parameter, the second texture parameter, and the third texture parameter, Image processing methods.

2. 2. The image processing method according to claim 1, (g) acquiring printing conditions that affect the amount of print recording material used when forming an image on the print medium; (h) determining the amount of print recording material using the print image data and the printing conditions, Image processing methods.

3. 2. The image processing method according to claim 1, In the step (c), the first texture parameter is set for each pixel constituting the print image. Image processing methods.

4. 2. The image processing method according to claim 1, In the step (e), the third texture parameter is set using a table in which the printing method and the third texture parameter are associated with each other. Image processing methods.

5. 2. The image processing method according to claim 1, The third texture parameter includes at least one of a fourth texture parameter representing the appearance of the print medium and a fifth texture parameter representing the movement of the print medium. Image processing methods.

6. 6. The image processing method according to claim 5, the third texture parameter includes the fourth texture parameter, the fourth texture parameter includes a correction value of the first texture parameter or a correction value of the second texture parameter, (i) further comprising a step of correcting the first texture parameter or the second texture parameter using the fourth texture parameter; Image processing methods.

7. 6. The image processing method according to claim 5, the third texture parameter includes the fifth texture parameter, In the step (f), the rendering image is generated using the fifth texture parameter; the rendered image is a moving image representing the movement of the print medium; Image processing methods.

8. An image processing device, an image data acquisition unit that acquires print image data including pixel values ​​of a print image formed on a print medium; a printing method acquisition unit that acquires a printing method that is a method for forming the print image on the print medium; a first texture setting unit that sets a first texture parameter that represents the texture of the surface of the printing medium due to the presence of the print recording material in accordance with a print recording material amount that is the amount of the print recording material used to form the print image; a second texture setting unit that sets a second texture parameter that represents the texture of the print medium itself; a third texture setting unit that sets a third texture parameter that represents a texture of the printing medium that depends on the printing method in accordance with the printing method; a rendering unit that generates a rendering image of the printing medium on which the print image is formed by a rendering process using the print image data, the first texture parameter, the second texture parameter, and the third texture parameter, Image processing device.

9. 1. A printing system comprising: The image processing device according to claim 8 ; a display device that displays the rendering image generated by the image processing device; and a printing device that prints the print image data on the print medium; Printing system.

10. An image processing program, (a) a function of acquiring print image data including pixel values ​​of a print image to be formed on a print medium; (b) a function of acquiring a printing method, which is a method of forming the print image on the print medium; (c) a function of setting a first texture parameter representing the texture of the surface of the printing medium due to the presence of the print recording material in accordance with the amount of the print recording material used to form the print image; (d) a function of setting a second texture parameter that represents the texture of the printing medium itself; (e) a function of setting a third texture parameter representing the texture of the printing medium depending on the printing method according to the printing method; (f) a function of generating a rendering image of the printing medium on which the printing image is formed by a rendering process using the printing image data, the first texture parameter, the second texture parameter, and the third texture parameter; An image processing program that enables a computer to achieve this.

Images