JP2022114569A - Image processing method, image processing device and printing system - Google Patents

Abstract

To provide an image processing method which can easily obtain a printed matter in which a sufficient texture that is required can be felt.SOLUTION: An image processing method comprises the steps of: generating a first ink amount map indicating an amount of first ink in an achromatic color used for reproducing a texture of a print image on the basis of at least one texture map among a height map indicating unevenness of a surface for reproducing the texture of the surface of an input image with printing, a normal line map indicating the normal direction of the surface, a roughness map indicating roughness of the surface, and an environment shielding map indicating the environment shielding state of the surface; generating a second ink amount map indicating an amount of second ink used for reproducing a hue of the print image on the basis of a hue map indicating the hue of the surface; and generating printing data for performing printing by controlling a printing device on the basis of the generated first ink amount map and second ink amount map.SELECTED DRAWING: Figure 8

Description

The present invention relates to an image processing method, an image processing apparatus, and a printing system.

Japanese Unexamined Patent Application Publication No. 2002-200003 describes an image processing apparatus that forms an image on a recording medium based on image data including color separation data and gloss data of an image.

Japanese Unexamined Patent Application Publication No. 2010-23291

However, in the image processing apparatus described in Patent Document 1, when the input data based on which the image to be recorded on the recording medium is only the color separation data and the gloss data of the image, it is possible to easily produce a printed matter with sufficient texture. There was a problem that it may not be obtained.

The image processing method of the present invention includes a height map indicating surface unevenness, a normal map indicating a normal direction of the surface, and a surface roughness map for reproducing the texture of the surface of an input image by printing. and an environmental shielding map indicating the environmental shielding state of the surface. generating a first ink amount map; generating a second ink amount map indicating the amount of the second ink used for color reproduction of the printed image based on the color map indicating the color of the surface; and generating print data for controlling a printing device to perform printing based on the generated first ink amount map and the second ink amount map.

The image processing apparatus of the present invention includes a height map indicating the unevenness of the surface, a normal map indicating the normal direction of the surface, and the roughness of the surface, for reproducing the texture of the surface of the input image by printing. a communication unit capable of acquiring at least one texture map out of a roughness map indicating roughness and an environment shielding map indicating the environment shielding state of the surface, and a color map indicating the color of the surface; Based on the texture map, a first ink amount map indicating the amount of the achromatic first ink used for texture reproduction of the printed image is generated, and based on the obtained color map, for color reproduction of the printed image. A second ink amount map indicating the amount of the second ink to be used is generated, and a printing apparatus is controlled based on the generated first ink amount map and the second ink amount map to perform printing. and a calculation unit that generates print data.

A printing system of the present invention includes the image processing device, a printing device that prints based on print data generated by the image processing device, and an imaging device that captures a print image printed by the printing device.

1 is a front view showing the configuration of a printing system according to an embodiment; FIG. 1 is a block diagram showing the configuration of a printing system according to an embodiment; FIG. FIG. 2 is an explanatory diagram of basic functions of a printer driver; FIG. 4 is a conceptual diagram showing a method of reproducing texture in a printed image based on a height map; FIG. 4 is a conceptual diagram showing a method of reproducing texture in a printed image based on a normal map; FIG. 4 is a conceptual diagram showing a method of reproducing texture in a printed image based on a roughness map; FIG. 10 is a conceptual diagram showing another method of reproducing texture in a printed image based on a roughness map; 4 is a flow chart showing the flow of an image processing method according to the embodiment;

A configuration and basic printing functions of a printing system 1 according to an embodiment will be described with reference to FIGS. 1 and 2. FIG.
In the coordinates attached to the drawings, the Z-axis direction is the vertical direction, the +Z direction is the upward direction, the X-axis direction is the front-back direction, the -X direction is the front direction, the Y-axis direction is the left-right direction, and the +Y direction is the left direction. The XY plane is the horizontal plane.

The printing system 1 includes a printing device 100 , an image processing device 110 connected to the printing device 100 , and an imaging device 70 built in the printing device 100 .
The printing apparatus 100 is an inkjet printer that prints a desired image on a long print medium 5 that is set in a rolled state based on print data received from an image processing apparatus 110 .
The print medium 5 is not particularly limited, but as will be described later, in order to more effectively reproduce the texture of the printed image with the achromatic first ink, the surface should be flat and the first ink It is preferable to have a relatively low degree of internal absorption of .

The image processing apparatus 110 includes a calculation unit 111, an input unit 112, a display unit 113, a storage unit 114, a PRT interface 119, a communication unit 120, and the like, and controls print jobs that cause the printing apparatus 100 to print. The image processing apparatus 110 also generates print data for causing the printing apparatus 100 to print a desired image based on the RGB image data and texture information such as a texture map to be described later. The image processing device 110 is configured using a personal computer as a preferred example.
The software on which the image processing apparatus 110 operates includes image processing application software having a rendering function for generating image data for forming a print image based on texture information such as RGB image data and texture maps, and software for the printing apparatus 100. It includes printer driver software that generates print data for controlling and causing the printing device 100 to perform printing. In the following description, image processing application software is simply called image processing application, and printer driver software is simply called printer driver.

The computing unit 111 includes a CPU 115, an ASIC 116, a DSP 117, a memory 118, and the like, and centrally manages the entire printing system 1. FIG. CPU means Central Processing Unit, ASIC means Application Specific Integrated Circuit, and DSP means Digital Signal Processor.

The input unit 112 is information input means as a user interface. Specifically, for example, it is a keyboard, a mouse pointer, and the like.
The display unit 113 is information display means as a user interface, and under the control of the calculation unit 111, displays information input from the input unit 112, images to be printed by the printing apparatus 100, information related to print jobs, and the like. Is displayed.

The storage unit 114 is a rewritable storage medium such as a hard disk drive or a memory card, and is related to programs that operate in the calculation unit 111 as software that the image processing apparatus 110 operates, data of images to be printed, and print jobs. information is stored.
The memory 118 is a storage medium that secures an area for storing a program for the CPU 115 to operate, a work area for the operation, and the like, and is configured by storage elements such as RAM and EEPROM. RAM means random access memory, and EEPROM means electrically erasable programmable read-only memory.

The communication unit 120 is an information transmission unit having an interface, such as a LAN interface and a USB interface, to which an external electronic device can be connected. Since the communication unit 120 is connected to the Internet line via a LAN, the image processing apparatus 110 can obtain various information from the World Wide Web and the like. LAN means Local Area Network, and USB means Universal Serial Bus.

The printing apparatus 100 includes a printing section 10, a moving section 20, a print control section 30, and the like. The printing apparatus 100 receives the print data from the image processing apparatus 110 and controls the printing unit 10 and the moving unit 20 by the print control unit 30 based on the print data, and prints an image on the print medium 5 .
The print data is data for image formation obtained by converting image data rendered by an image processing application so that it can be printed by the printer driver 100 , and includes commands for controlling the printer 100 .

The printing section 10 includes a head unit 11, an ink supply section 12, and the like.
The moving section 20 includes a scanning section 40, a conveying section 50, and the like.
The scanning unit 40 includes a carriage 41, a guide shaft 42, a carriage motor, and the like. A carriage motor is omitted from the drawing.
The conveying section 50 includes a supply section 51, a storage section 52, a conveying roller 53, a platen 55, and the like.

The head unit 11 includes a head 13 and a head control section 14 each having a plurality of nozzle rows each having a plurality of nozzles for ejecting printing ink as ink droplets. The head unit 11 is mounted on a carriage 41 and reciprocates in the X-axis direction with the carriage 41 moving in the X-axis direction as the scanning direction.

The ink supply unit 12 includes an ink tank and an ink supply path for supplying ink from the ink tank to the head 13 . Illustrations of the ink tank and the ink supply path are omitted.
An ink tank, an ink supply path, and an ink supply path to nozzles that eject the same ink are provided independently for each ink.

For ink, cyan ink C, magenta ink M, and yellow ink Y, which enable full-color reproduction, are added to the 3-color ink set, and black ink K is added. Three types of ink, ie, ink W, colorless and transparent clear ink Dv, and black ink K are used.
In the present embodiment, the second ink is the four inks of cyan ink C, magenta ink M, yellow ink Y, and black ink K used for full-color reproduction, and the white ink used for texture reproduction. The three types of ink, W, clear ink Dv, and black ink K, are achromatic first inks. The black ink K can be used both as the first ink and as the second ink.
It should be noted that the second ink is not limited to the four colors of ink described above. For example, eight colors of ink may be used, including light cyan ink LC, light magenta ink LM, light yellow ink LY, and light black ink LK, each of which has a lighter density. Further, the light black ink LK may be added to the first ink, and the achromatic ink used for the first ink may be used as the second ink for full color reproduction.

The moving unit 20 , that is, the scanning unit 40 and the conveying unit 50 , moves the print medium 5 relative to the head 13 under the control of the print control unit 30 .
The guide shaft 42 extends in the X-axis direction and supports the carriage 41 in a slidable state. The carriage motor also serves as a drive source for reciprocating the carriage 41 along the guide shaft 42 . In other words, the scanning unit 40 moves the carriage 41 , that is, the head 13 along the guide shaft 42 in the X-axis direction under the control of the print control unit 30 . The head 13 provided in the head unit 11 mounted on the carriage 41 ejects ink droplets onto the print medium 5 supported by the platen 55 under the control of the print control unit 30 while moving in the X-axis direction. , a plurality of dot rows are formed on the print medium 5 along the X-axis direction.

The supply unit 51 rotatably supports a reel on which the print medium 5 is wound, and feeds the print medium 5 to the transport path. The storage unit 52 rotatably supports a reel for winding the print medium 5, and winds the printed print medium 5 from the transport path.
The transport roller 53 includes a drive roller that moves the print medium 5 in the Y-axis direction, which is the transport direction, on the upper surface of the platen 55 and a driven roller that rotates as the print medium 5 moves. , through the printing area of the printing unit 10 and conveying to the storage unit 52 . The print area is the area where the head 13 moves in the X-axis direction on the upper surface of the platen 55 .

The print control unit 30 includes a PC interface 31 , a CPU 32 , a memory 33 , a drive control unit 34 and the like, and controls the printing apparatus 100 .
The PC interface 31 is connected to the PRT interface 119 of the image processing apparatus 110 and transmits and receives data between the image processing apparatus 110 and the printing apparatus 100 . Note that the PC interface 31 may be connected to the communication unit 120 when the PC interface 31 can transmit and receive data to and from the communication unit 120 of the image processing apparatus 110 . Also, in that case, the image processing apparatus 110 does not have to include the PRT interface 119 .

The CPU 32 is an arithmetic processing unit for controlling the entire printing apparatus 100 .
The memory 33 is a storage medium that secures an area for storing a program for the CPU 32 to operate, a work area for the operation, and the like, and is composed of storage elements such as RAM and EEPROM.
The CPU 32 controls the printing unit 10 and the moving unit 20 via the drive control unit 34 according to the programs stored in the memory 33 and the print data received from the image processing device 110 .

The drive control section 34 includes firmware that operates under the control of the CPU 32 , and controls driving of the head unit 11 and ink supply section 12 of the printing section 10 and the scanning section 40 and transport section 50 of the moving section 20 . The drive control unit 34 includes a drive control circuit including a movement control signal generation circuit 35, an ejection control signal generation circuit 36, a drive signal generation circuit 37, etc., and a ROM or flash memory containing firmware for controlling these drive control circuits. It is ROM and flash memory containing firmware for controlling the drive control circuit are not shown. Here, ROM means Read-Only Memory.

The movement control signal generation circuit 35 is a circuit that generates signals for controlling the scanning section 40 and the transport section 50 of the moving section 20 according to instructions from the CPU 32 based on the print data.
The ejection control signal generation circuit 36 is a circuit for generating head control signals for selecting nozzles for ejecting ink, selecting the amount of ink to be ejected, controlling the timing of ejection, etc., according to instructions from the CPU 32 based on print data. is.
The drive signal generation circuit 37 is a circuit that generates a drive signal for driving the pressure generation chambers provided in the head 13 .

With the above configuration, the print control unit 30 moves the carriage 41 supporting the head 13 along the guide shaft 42 in the X-axis direction with respect to the print medium 5 supplied to the print area by the supply unit 51 and the transport roller 53. A desired image is printed on the print medium 5 by repeating the operation of ejecting ink droplets from the head 13 and the operation of moving the print medium 5 in the +Y direction that intersects the X-axis direction by the transport roller 53 .

The imaging device 70 includes a light source 71 and a digital camera 72, and is capable of imaging a print image printed on the print medium 5 transported to an imaging area downstream of the print area in the transport path of the print medium 5. is provided in
The digital camera 72 is provided at a position facing the platen 55 in the imaging area, and the light source 71 is provided so as to change the position at which the imaging area is irradiated with light.
The digital camera 72 is connected to the communication unit 120 of the image processing device 110 , and under the control of the image processing device 110 , captures an image to be printed and transmits captured image data to the image processing device 110 . can be done.

Printing on the print medium 5 is started by sending print data from the image processing device 110 to the printing device 100 .
The print data generation process performed by the printer driver will be described below with reference to FIG. Note that the print data generation processing described below is for conceptually explaining the basic flow of the print data generation processing. Therefore, the image data corresponding to the later-described color map is mainly described.

The printer driver receives image data from the image processing application, converts it into print data in a format that can be interpreted by the printing apparatus 100 , and outputs the print data to the printing apparatus 100 . When converting image data from an image processing application into print data, the printer driver performs resolution conversion processing, color conversion processing, halftone processing, rasterization processing, command addition processing, and the like.

The resolution conversion process is a process of converting the image data output from the image processing application into the resolution for printing on the print medium 5 . For example, if the resolution for printing is specified as 720×720 dpi, the vector format image data received from the image processing application is converted into bitmap format image data with a resolution of 720×720 dpi. Each pixel data of the image data after resolution conversion processing is composed of pixels arranged in a matrix. Each pixel has a gradation value of, for example, 256 gradations in the RGB color space corresponding to the color map. That is, the pixel data after resolution conversion indicates the gradation value of the corresponding pixel. Hereinafter, tone value data in the RGB color space will be referred to as RGB data.
Pixel data corresponding to one row of pixels arranged in a predetermined direction among pixels arranged in a matrix is called raster data. The predetermined direction in which the pixels corresponding to the raster data are arranged corresponds to the moving direction of the head 13 when printing an image, specifically the X-axis direction.

Color conversion processing is processing for converting RGB data of image data into gradation value data in the CMYK color space. The CMYK colors are cyan, magenta, yellow, and black, and the image data in the CMYK color space is data corresponding to the ink colors of the printing apparatus 100 . Therefore, for example, when the printing apparatus 100 uses four types of CMYK color inks, the printer driver generates four-dimensional space image data in the CMYK color system based on the RGB data. Gradation value data in the CMYK color space is ink amount data. Here, the gradation value data of the CMYK color space is called CMYK data, and the information of the ink amount data arranged in a matrix is called an ink amount map.
This color conversion processing is performed based on a color conversion lookup table that associates the gradation values of RGB data with the gradation values of CMYK data. The pixel data after color conversion processing is, for example, 256-tone CMYK data represented by the CMYK color space.

Halftone processing is processing for converting data with a high number of gradations, for example, data with 256 gradations, into data with a number of gradations that can be formed by the printing apparatus 100 . This halftone processing converts data representing 256 gradations into 2-bit halftone data representing 4 gradations of no dot, small dot, medium dot, and large dot. Specifically, the dot generation rate corresponding to the gradation value is obtained from a dot generation rate table in which the gradation value from 0 to 255 corresponds to the dot generation rate. As for the dot generation rate obtained corresponding to the gradation value, the respective generation rates of no dots, small dots, medium dots, and large dots are obtained. At each of the obtained generation ratios, pixel data is created by using a dither method, an error diffusion method, or the like so that dots are dispersedly formed.

The dot generation rate table is a table that associates the gradation value for each pixel included in the image data with the dot generation rate for each dot size of the dots formed on the printing medium 5 by the printing apparatus 100. For each ink color, It is stored in the memory 33 within the printing apparatus 100 . The total sum of products of the ejection amount per dot of each dot size and the number of generated dots is the ink ejection amount.

The rasterizing process is a process of rearranging the 2-bit pixel data arranged in a matrix according to the order of dot formation during printing. The rasterizing process includes a pass allocation process that allocates image data composed of pixel data after halftone processing to each pass in which ink droplets are ejected while the head 13 moves. After pass allocation is completed, the actual nozzles that form each raster line that make up the printed image are allocated.

The command addition process is a process of adding command data corresponding to the printing method to rasterized data. Examples of command data include transport data related to transport specifications of the print medium 5 as data for controlling the moving unit 20 . The transport specifications are, for example, the amount of movement and speed of the print medium 5 on the upper surface of the platen 55 in the transport direction. Data for controlling the moving section 20 includes data for controlling the speed of the carriage 41 in the scanning section 40 .
The series of processes by the printer driver is performed by the ASIC 116 and the DSP 117 under the control of the CPU 115. In the print data transmission process, the print data generated by the series of processes is sent to the printer 100 via the PRT interface 119. sent.

In addition to the basic printing functions described above, the printing system 1 is characterized by having a function of reproducing the texture of the surface of the input image on the surface of the printed matter. Specifically, for example, it is a function that reproduces the texture such as unevenness of the surface of leather or the texture such as the glossiness of plastic or metal on the surface of the printed material based on the texture information of the input image.
A function for reproducing the texture of the surface of an input image on the surface of a printed matter will be specifically described below.

In the present embodiment, the texture information of the input image is information for reproducing the texture of the surface of the input image, and includes a height map indicating the unevenness of the surface and a normal map indicating the normal direction of the surface. , a roughness map indicating the roughness of the surface and an environment shielding map indicating the environment shielding state of the surface. Information on these texture maps can be easily obtained as texture data through the World Wide Web, etc., together with a color map that indicates the color of the surface.

The height map is information having map information in a matrix form, in which height information on the unevenness of the surface of the input image is expressed as gradation values for each pixel of the input image. A height map is an image in which, for example, the gradation value indicating height is replaced with a gradation value of brightness, that is, when viewed as a grayscale image, whiter areas indicate higher areas, and darker areas indicate lower areas. obtained as image data shown.

The normal map is information having information on the normal direction of the unevenness of the surface of the input image as map information in a matrix as vector information for each pixel of the input image. The vector information has xyz three-dimensional information. For example, the x component of the normal vector is the R tone value, the y component of the normal vector is the G tone value, and the z component of the normal vector is obtained as image data with B as the gradation value. Note that xyz are coordinate values in an input image space independent of the XYZ coordinate space shown in FIG.

The roughness map is information having the roughness of the surface of the input image, that is, information such as smoothness and roughness as map information in a matrix as gradation values for each pixel of the input image. For example, a gradation value of 1 indicates a smooth and glossy state, and a gradation value of 100 indicates a rough and matte state.

In addition to the direct light from the light source, the environment shielding map is a matrix of shading information that takes into account the effects of indirect light from the surrounding environment as gradation values for each pixel of the input image. It is information that has as This indicates that the more the indirect light from the surrounding environment is blocked, the lower the brightness of the shadow.

The color map is image data in the above description, that is, data of an image that serves as a base to which texture information is to be added, and is composed of RGB data that indicates the color of each pixel. Color maps may include patterns and images.

In the present embodiment, the printing system 1 reproduces the texture based on the texture map described above using the achromatic first ink described above. A specific method will be described below with reference to FIGS. 4 to 7. FIG.

As shown in FIG. 4, the reproduction of the texture based on the height map is performed by using the white ink W as the first ink I1 so as to form unevenness in the printed image corresponding to the unevenness of the surface of the input image. This is done by forming a base with Specifically, before forming an image based on the color map with the second ink I2, the amount of white ink W corresponding to the gradation values (h1 to h10) of the height map is applied to the print medium 5. In other words, at pixel positions where the gradation value (hn) of the height map is large and the height is to be increased, more white ink W is laminated to form a higher base. It is preferable that the gradation value (hn) of the height map and the thickness tn of the base on which the white ink W is laminated have a relationship of tn=hn×k1. Here, n is a natural number assigned to each pixel, and k1 is a coefficient. It is preferable that the magnitude of k1 is determined in advance through sufficient evaluation.
The formation of the image with the second ink I2 based on the color map is performed after the underlying white ink W has dried to such an extent that the second ink I2 does not bleed into the underlying white ink W.
That is, the first ink I1, the amount of which is determined based on the height map, is an achromatic ink that forms the base of the printed image printed with the second ink I2.

As shown in FIG. 5, the reproduction of the texture based on the normal map is performed by using white ink W as the first ink I1 so that unevenness is formed on the printed image corresponding to the normal direction of the surface of the input image. This is done by forming an uneven base. Specifically, before forming an image based on the color map with the second ink I2, the gradation value (hn) is such that the distribution of the surface with inclination corresponding to the inclination direction of the normal vector of the normal map is obtained. is generated, and a base is formed with white ink W based on the generated height map. It is preferable that the gradation value (hn) of the height map derived from the normal map and the thickness tn of the base on which the white ink W is laminated have a relationship of tn=hn×k2. Here, k2 is a coefficient, and its magnitude is preferably determined in advance through sufficient evaluation.
The formation of the image with the second ink I2 based on the color map is performed after the underlying white ink W has dried to such an extent that the second ink I2 does not bleed into the underlying white ink W.
That is, the first ink I1, the amount of which is determined based on the normal map, is an achromatic ink that forms the base of the printed image printed with the second ink I2.

As shown in FIG. 6, the reproduction of the texture based on the roughness map is performed using white as the first ink I1 so that fine irregularities are formed on the surface of the printed image corresponding to the surface roughness of the input image. This is done by forming a base with fine unevenness with the ink W. FIG. Specifically, before forming an image based on the color map with the second ink I2, the white ink W having a dot size and a dot density corresponding to the gradation value (rn) of the roughness map is obtained. is applied to the print medium 5 to form a substrate. FIG. 6 shows an example in which the printed image on the left has a rougher surface than the printed image on the right. The dot size ds and the dot density dd of the white ink W formed corresponding to the gradation value (rn) of the roughness map have the relationships of ds=rn×k3 and dd=rn×k4. preferable. Here, k3 and k4 are coefficients, and it is preferable that the respective magnitudes are determined in advance through sufficient evaluation.
The formation of the image with the second ink I2 based on the color map is performed after the underlying white ink W has dried to such an extent that the second ink I2 does not bleed into the underlying white ink W.
That is, the first ink I1, the amount of which is determined based on the roughness map, is an achromatic ink that forms the base of the printed image printed with the second ink I2.

In addition, as shown in FIG. 7, the texture reproduction based on the roughness map is such that the surface matte texture of the printed image is reduced in correspondence with the smooth texture that is the surface roughness of the input image. The surface of the printed image printed with the second ink I2 may be covered with the clear ink Dv as I1. Specifically, after forming an image based on the color map with the second ink I2, the smaller the gradation value (rn) of the roughness map, that is, the more the smooth feeling increases, the more transparent the clear ink Dv becomes. Thickness to coat with a layer is formed. FIG. 7 shows an example in which the printed image on the right side has a smoother surface than the printed image on the left side. The gradation value (rn) of the roughness map and the thickness cn of the coating layer of the clear ink Dv preferably have a relationship of cn=1÷rn×k5. Here, k5 is a coefficient, and its magnitude is preferably determined in advance by performing sufficient evaluation.
Reproduction of the texture by the clear ink Dv as the first ink I1 is performed after the second ink I2 has dried to such an extent that the clear ink Dv does not bleed into the second ink I2.
That is, the first ink I1, the amount of which is determined based on the roughness map, is a transparent ink that forms the surface of the printed image printed with the second ink I2.

Reproduction of the texture based on the environment shielding map is performed by lowering the brightness of the printed image in accordance with the information of the degree of shielding of the indirect light from the surrounding environment contained in the environment shielding map. Specifically, after forming an image based on the color map with the second ink I2, black ink K having an ink amount corresponding to the gradation value (sn) of the environment shielding map, or light black ink as the first ink When LK is used, light black ink LK is applied to the printing medium 5, that is, more black ink K or light black ink LK is applied to pixel positions where brightness is to be lowered. represent shadows. The gradation value (sn) of the environment shielding map and the ink amount an of the applied black ink K or light black ink LK preferably have a relationship of an=sn×k6. Here, k6 is a coefficient, and its magnitude is preferably determined in advance through sufficient evaluation.
The reproduction of the texture based on the environment shielding map corresponds to the information of the degree of shielding of the indirect light from the surrounding environment possessed by the environment shielding map. , and the lightness of the area irradiated with the indirect light may be increased. That is, after forming an image based on the color map with the second ink I2, the amount of white ink W corresponding to the gradation value (sn) of the environment shielding map is applied to the print medium 5 to increase the brightness. A larger amount of white ink W may be applied to the pixel positions to be printed.
That is, the first ink I1, the amount of which is determined based on the environmental shielding map, is an achromatic ink that changes the lightness of the printed image printed with the second ink I2.

Next, the image processing method of this embodiment will be described with reference to the flowchart shown in FIG. The image processing method of the present embodiment is an image processing method for performing printing that reproduces a desired texture based on texture information such as texture data acquired through the World Wide Web, that is, the texture map described above, in the printing system 1. , and is executed according to an operation from the input unit 112 by a program that operates in the calculation unit 111 of the image processing apparatus 110 .

The image processing method of this embodiment is used to reproduce the texture of a printed image based on at least one of the above-described height map, normal map, roughness map, and environment shielding map. A step of generating a first ink amount map indicating the amount of the achromatic first ink, and a second ink amount map indicating the amount of the second ink used for color reproduction of the printed image based on the color map described above. and generating print data for controlling the printing apparatus 100 to perform printing based on the generated first ink amount map and second ink amount map. and

In addition, the image processing method of the present embodiment generates rendered image data based on at least one texture map of a height map, a normal map, a roughness map, and an environment occluded map, and a color map. a step of obtaining a first texture parameter based on the lightness distribution of the generated image data; a step of imaging a print image printed based on the print data to obtain the imaged data; and the obtained imaged data. a step of obtaining a second texture parameter based on the lightness distribution; a step of comparing the obtained first texture parameter and the second texture parameter to calculate a difference amount; generating print data by correcting the first ink amount map and/or the second ink amount map based on the amount of difference when the threshold is exceeded.
A specific description will be given below.

First, in step S1, the image processing apparatus 110 acquires image data to be printed and texture data necessary for texture expression. Specifically, for example, desired height map, normal map, roughness map, texture map such as environment shielding map, and color map information are obtained through the World Wide Web. Note that information on a plurality of texture maps and color maps may be acquired in advance and stored in the storage unit 114, and may be acquired by selecting from among them.

Next, in step S2, texture reproduction specifications for an image to be printed are set. Specifically, a texture map to be used for texture reproduction is selected, and the degree of texture expression is set as necessary. At least one texture map is selected from the obtained height map, normal map, roughness map, and environmental shielding map. That is, the image processing method of the present embodiment includes the step of selecting at least one texture map among the height map, normal map, roughness map, and environment shielding map.
The setting of the degree of texture expression is, for example, the setting of unevenness, roughness, glossiness, etc., and can be performed in the function of the image processing application. Specifically, through the user interface screen in the image processing application function, the user arbitrarily changes the values of the above-described counts k1 to k6 to values different from the preset values within a predetermined range. It can be done by A user interface screen is displayed on the display unit 113, and input reflected in the settings of the counts k1 to k6 can be made via the input unit 112. FIG.

Next, in step S3, the calculation unit 111 performs rendering based on the selected texture map and color map using the function of the image processing application to generate image data. That is, the image processing method of the present embodiment generates rendered image data based on at least one texture map among a height map, a normal map, a roughness map, and an environment occluded map, and a color map. Includes process.
For rendering, viewing conditions such as the position of a virtual light source and viewing position for visually recognizing unevenness, roughness, and glossiness can be set in the rendering function of the image processing application. An image to be printed is displayed on the display unit 113 based on the rendered image data.

Next, in step S4, the calculation unit 111 analyzes the generated image data and obtains a first texture parameter based on the brightness distribution of the image data. That is, the image processing method of this embodiment includes a step of obtaining the first texture parameter based on the brightness distribution of the generated image data. Here, the texture parameter is the skewness and/or standard deviation of the brightness distribution of the image data.

The degree of skewness in the brightness distribution of image data is known as a parameter related to the glossiness of an image. Specifically, the higher the glossiness of the image, the longer the tail in the direction of higher lightness. In other words, the higher the glossiness of the image, the stronger the positive skewness of the lightness distribution. Conversely, an image in which the brightness distribution has a negative degree of skewness is an image with a high degree of matte feeling.
Also, the standard deviation in the lightness distribution of image data is known as a parameter related to image roughness and roughness. Specifically, the more rough the image, the larger the standard deviation in the lightness distribution.
Also, the texture parameter based on the brightness distribution of the rendered image data is the first texture parameter in this embodiment.

After step S4, or in parallel with the processing of steps S3 and S4, in step S5, the calculation unit 111 calculates the texture map of the print image based on the texture map selected in step S2. A first ink amount map indicating the amount of the first ink for coloring is generated, and based on the obtained color map, a second ink amount map indicating the amount of the second ink used for color reproduction of the printed image is generated. do. That is, the image processing method of the present embodiment is based on at least one texture map among the height map, normal map, roughness map, and environment shielding map. a step of generating a first ink amount map indicating the amount of one ink; and a step of generating a second ink amount map indicating the amount of a second ink used for color reproduction of a printed image based on the color map. contains.

As described above, the first ink amount map is generated as map data consisting of the amount of the first ink for each pixel calculated based on the gradation value for each pixel of the selected texture map. The generation of the first ink amount map is executed as a function of the printer driver described above, but may be executed as a function of the first ink amount map generation program independent of the printer driver.
The generation of the second ink amount map based on the color map is executed in the function of the printer driver described above.

Next, in step S6, the calculation unit 111 generates print data for controlling the printing apparatus 100 to perform printing based on the generated first ink amount map and second ink amount map. That is, the image processing method of the present embodiment includes a step of generating print data for printing by controlling the printing apparatus 100 based on the generated first ink amount map and second ink amount map. contains.
The print data is obtained by executing the above-described halftone process and subsequent processes in the printer driver based on the ink amount map obtained by merging the first ink amount map and the second ink amount map.

Next, in step S7, the calculation unit 111 transmits the generated print data to the printing device 100, and causes the printing device 100 to execute printing based on the print data.
The printing device 100 that has received the print data executes printing, and the imaging device 70 captures the printed print image and transmits the captured data to the image processing device 110 in step S8. That is, the image processing method of the present embodiment includes a step of capturing a print image printed based on print data and acquiring captured image data.
Specifically, when printing is completed and the print image is conveyed to the imaging area downstream of the printing area, the printing apparatus 100 transmits a print completion signal from the PC interface 31 to the image processing apparatus 110 and receives the print completion signal. The image processing device 110 that has received the command transmits a signal of an imaging execution instruction to the imaging device 70 . The imaging device 70 that has received the imaging execution instruction drives the light source 71 and the digital camera 72 to capture the print image of the printing medium 5 transported to the imaging area, and transmits the imaging data to the image processing device 110 .

The positions of the light source 71 and the digital camera 72 with respect to the print image when capturing the print image, that is, the viewing conditions when capturing the image may be set based on the viewing conditions when rendering is performed by the function of the image processing application. desirable. That is, in the image processing method of the present embodiment, at least one of the height map, the normal map, the roughness map, and the environment shielding map, and the color map are used as the viewing conditions for rendering. Based on this, it is preferable to set the observation conditions when capturing the printed image based on the print data. Specifically, it is preferable to match the viewing conditions for imaging with the viewing conditions for rendering as much as possible, that is, match the direction of the light source with respect to the unevenness of the image to be reproduced.

Next, in step S9, the calculation unit 111 analyzes the received imaging data and obtains a second texture parameter based on the brightness distribution of the imaging data. That is, the image processing method of this embodiment includes a step of obtaining the second texture parameter based on the brightness distribution of the captured image data. The second texture parameter obtained here is a texture parameter comparable to the first texture parameter obtained in step S4, and is the degree of skewness and/or standard deviation in the brightness distribution of the imaging data.

Next, in step S10, the calculation unit 111 compares the first texture parameter obtained in step S4 and the second texture parameter obtained in step S9, and calculates the amount of difference. That is, the image processing method of this embodiment includes a step of comparing the obtained first texture parameter and second texture parameter and calculating the amount of difference. The skewness and/or the standard deviation of the lightness distribution are obtained as the amount of difference in the texture parameter. That is, by comparing the rendered image and the printed image, it is possible to quantitatively obtain the difference in gloss and roughness.

Next, in step S11, the calculation unit 111 determines whether or not the obtained difference amount of the texture parameter is equal to or less than a preset threshold value. The preset threshold value is a value for setting an allowable range in which the texture reproduced in the printed image is judged to be close to the desired texture. It is desirable to set this threshold in advance based on sufficient evaluation.
If the calculated difference amount of the texture parameter is equal to or less than the set threshold value, the calculation unit 111 determines that the desired texture can be reproduced by printing based on the print data generated at this time. to end the process.

In step S11, if the calculated difference amount of the texture parameter exceeds the threshold, in step S12, the calculation unit 111 calculates the first ink amount map and/or the second ink amount map generated in step S5 based on the difference amount. Correct the ink amount map. The correction of the first ink quantity map and/or the second ink quantity map depends on the type of texture parameter exceeding the threshold, i.e., skewness or standard deviation, and the polarity of the difference amount, i.e., the first texture parameter and This is performed based on preset correction specifications based on the magnitude relationship of the second texture parameter and the magnitude of the difference amount. The preset correction specification is a specification for correcting the first ink amount map and/or the second ink amount map so that the texture parameter difference amount becomes a smaller value. , the type of texture parameter exceeding the threshold, the polarity of the amount of difference, and the magnitude of the amount of difference.
That is, the image processing method of the present embodiment generates print data by correcting the first ink amount map and/or the second ink amount map based on the difference amount when the difference amount exceeds a predetermined threshold value. Includes process.

Next, returning to step S6, the calculation unit 111 generates print data based on the corrected first ink amount map and second ink amount map. Henceforth, step S7 to step S11 are performed again.
In step S11, the difference amount obtained by comparing the second texture parameter obtained from the print image based on the newly generated print data and the first texture parameter obtained in step S4 is determined. In the determination, if the difference amount does not become equal to or less than the threshold value, the processing after step S12 is repeated.
If it is feared that the processing time will be lengthened by repeating the processing after step S12, a processing for accepting an instruction as to whether or not to continue the processing may be added in step S12. Alternatively, if it is determined that further improvement cannot be expected by correcting the correction table in step S12, specifically, for example, if the calculation unit 111 determines that there is no corresponding correction table, the determination It may be configured to notify the result and terminate the process.

Further, the correction of the first ink amount map and/or the second ink amount map in step S12 may be performed based on the correction specifications specified by the user, instead of based on the preset correction specifications. good. Specifically, the correction of the first ink amount map is open to the user, and the user can set the values of the above-mentioned coefficients k1 to k6 in advance within a predetermined range based on the result of viewing the printed image. It can be done by arbitrarily changing to a value different from the value specified. That is, the image processing method may include a step of correcting or setting the amount of the first ink determined based on the texture map.

When the features of the image processing method described above are regarded as features of the image processing apparatus 110 that generates print data, the image processing apparatus 110 of the present embodiment can reproduce the surface texture of an input image by printing. At least one of a height map indicating the unevenness of the surface, a normal map indicating the normal direction of the surface, a roughness map indicating the roughness of the surface, and an environment shielding map indicating the environment shielding state of the surface. A communication unit 120 capable of acquiring a map and a color map indicating the color of the surface, and a first ink amount indicating the amount of the achromatic first ink used for reproducing the texture of the printed image based on the obtained texture map. generating a map; generating a second ink amount map indicating the amount of the second ink used for color reproduction of the printed image based on the obtained color map; generating the first ink amount map and the second ink; and a calculation unit 111 that generates print data for controlling the printing apparatus 100 to perform printing based on the amount map.

In the image processing device 110, the calculation unit 111 generates image data rendered based on at least one texture map among the height map, the normal map, the roughness map, and the environmental shielding map, and the color map. A first texture parameter is obtained based on the lightness distribution of the generated image data, and imaging data obtained by imaging a print image printed based on the print data is acquired via the communication unit 120. , a second texture parameter is obtained based on the brightness distribution of the acquired imaging data, the obtained first texture parameter and the second texture parameter are compared, and if the amount of difference exceeds a predetermined threshold, , correcting the first ink amount map and/or the second ink amount map based on the amount of difference to generate print data.

In the above description, the comparison between the rendered image and the printed image is performed by the skewness and/or standard deviation of the brightness distribution of each image. is not limited to, for example, a parameter with which contrast, color difference, or the like can be compared may be used.

According to this embodiment, the following effects can be obtained.
The image processing method of this embodiment includes steps of generating a first ink amount map indicating the amount of the first achromatic ink used for reproducing the texture of the printed image; and C. generating a second ink quantity map indicating the quantity of ink. Also, based on the generated first ink amount map and second ink amount map, print data for controlling the printing apparatus 100 to perform printing is generated. The amount of the first achromatic ink used for reproducing the texture of the printed image indicates a height map showing surface unevenness and the normal direction of the surface for reproducing the texture of the input image surface by printing. A first ink amount map is generated based on at least one of a normal map, a roughness map indicating surface roughness, and an environment shielding map indicating an environment shielding state of the surface. Information on these texture maps can be easily obtained through the World Wide Web and the like. As a result, it is possible to easily obtain a printed matter that gives a sufficient sense of texture as required.

According to the image processing method of the present embodiment, the brightness distribution of image data rendered based on at least one of the height map, normal map, roughness map, and environment shielding map, and the color map. , a first texture parameter is obtained. A printed image printed with print data generated based on a first ink amount map used for reproducing the texture of the printed image and a second ink amount map used for reproducing the color of the printed image is captured. A second texture parameter is obtained based on the lightness distribution of the imaging data obtained by the method.
Also, the obtained first texture parameter and second texture parameter are compared, and if the amount of difference exceeds a predetermined threshold, the first ink amount map and/or the second ink A volume map is corrected. Therefore, by performing printing based on the print data obtained as a result, it is possible to obtain a printed image that reproduces a texture that is closer to the image obtained as a result of rendering.

In the image processing method of the present embodiment, it is preferable to set the viewing conditions for capturing the print image printed based on the print data based on the viewing conditions for rendering. By capturing the printed image under viewing conditions that are close to those used for rendering, it is possible to more appropriately evaluate texture reproducibility. be able to obtain

According to this embodiment, the first ink amount map and/or the second 2 The ink amount map is corrected. The skewness obtained from the lightness distribution of the image can be obtained as a texture parameter that reproduces the glossiness of the image. Also, the standard deviation obtained from the lightness distribution of the image can be obtained as a texture parameter that reproduces the texture such as roughness of the image surface. Therefore, by performing printing based on print data corrected so that the amount of difference in these texture parameters is equal to or less than a predetermined threshold value, it is possible to obtain a printed image that reproduces a texture that is closer to the image obtained as a result of rendering. will be able to

The first ink, the amount of which is determined based on the height map, is a neutral ink that forms the base of the printed image printed with the second ink. Since the achromatic first ink forms the base of the print image printed with the second ink based on the height map, that is, the achromatic first ink gives the surface of the image obtained from the height map. Since it is possible to form a base having a thickness corresponding to the value of the height, it is possible to reproduce the texture related to the height of the surface of the printed image printed with the second ink.

The first ink, the amount of which is determined based on the normal map, is a neutral ink that forms the base of the printed image printed with the second ink. Since the achromatic first ink forms the base of the printed image printed with the second ink based on the normal map, that is, the achromatic first ink provides the surface of the image obtained from the normal map. Since it is possible to form a base with an inclination corresponding to the value of the inclination, it is possible to reproduce the texture associated with the inclination of the surface of the printed image printed with the second ink.

If the first ink, the amount of which is determined based on the roughness map, is an achromatic ink that forms the base of the printed image printed with the second ink, the achromatic first ink, based on the roughness map, A base for the printed image printed with the second ink is formed. In other words, since the achromatic first ink can form an underlayer with a roughness corresponding to the roughness value of the image surface obtained from the roughness map, the surface of the printed image printed with the second ink It is possible to reproduce the texture related to the roughness of the

Further, when the first ink, the amount of which is determined based on the roughness map, is a transparent ink that forms the surface of the printed image printed with the second ink, the transparent first ink, based on the roughness map, A printed image surface printed with the second ink is formed. That is, the transparent first ink can form a surface with roughness corresponding to the roughness value of the image surface obtained from the roughness map. It is possible to reproduce textures related to roughness.

The first ink, the amount of which is determined based on the environmental shielding map, is a neutral ink that modifies the brightness of the printed image printed with the second ink. Because the lightness-changing achromatic ink changes the lightness of the printed image printed with the second ink based on the environmental shielding map, that is, the lightness-changing achromatic ink gives the image obtained from the environmental shielding map. Since shading can be expressed in correspondence with values related to lightness such as shading, it is possible to reproduce the environment shielding condition of the printed image printed with the second ink.

The image processing method of the present embodiment further includes selecting at least one texture map from the height map, the normal map, the roughness map, and the environment shielding map, and based on the selected texture map, the first Generate an ink amount map. Therefore, when printing a print image, it is possible to select the texture to be expressed.

The image processing method of this embodiment may include a step of correcting or setting the amount of the first ink determined based on the texture map. In this case, when printing the print image, it is possible to correct or set the degree of texture expressed corresponding to the texture map.

According to the image processing apparatus 110 of the present embodiment, the first ink amount map indicating the amount of the first achromatic ink used for reproducing the texture of the printed image is generated, and the first ink amount map used for reproducing the color of the printed image is generated. A second ink quantity map is generated that indicates the quantity of two inks. Also, based on the generated first ink amount map and second ink amount map, print data for controlling the printing apparatus 100 to perform printing is generated. The amount of the first achromatic ink used for reproducing the texture of the printed image indicates a height map showing surface unevenness and the normal direction of the surface for reproducing the texture of the input image surface by printing. A first ink amount map is generated based on at least one of a normal map, a roughness map indicating surface roughness, and an environment shielding map indicating an environment shielding state of the surface. The information of these texture maps can be easily obtained by the communication unit 120 through the World Wide Web or the like. As a result, it is possible to easily obtain a printed matter that gives a sufficient sense of texture as required.

According to the image processing apparatus 110 of the present embodiment, the brightness of image data rendered based on at least one texture map among the height map, normal map, roughness map, and environment shielding map, and the color map. A first texture parameter is determined based on the distribution. A printed image printed with print data generated based on a first ink amount map used for reproducing the texture of the printed image and a second ink amount map used for reproducing the color of the printed image is captured. A second texture parameter is obtained based on the lightness distribution of the imaging data obtained by the method.
Also, the obtained first texture parameter and second texture parameter are compared, and if the amount of difference exceeds a predetermined threshold, the first ink amount map and/or the second ink A volume map is corrected. Therefore, by performing printing based on the print data obtained as a result, it is possible to obtain a printed image that reproduces a texture that is closer to the image obtained as a result of rendering.

According to the printing system 1 of the present embodiment, it is possible to easily obtain a printed matter with a sufficient texture that is required.

In the present embodiment, the printing apparatus 100 is described as an inkjet printer that prints on a long print medium 5 that is supplied in a rolled state. The print medium 5 is not limited to the roll-shaped print medium 5, and may be a sheet-fed cut-sheet paper or the like. In the case of sheet-fed paper, instead of the supply unit 51, for example, a supply mechanism including a separator for supplying paper one by one is provided, and instead of the storage unit 52, for example, it is discharged after printing. The configuration is such that a storage tray or the like is provided for storing the sheets to be printed.

Further, in the printing system 1 of the present embodiment, the configuration in which the imaging device 70 is incorporated in the printing device 100 has been described, but the imaging device 70 may be provided independently of the printing device 100 . When the imaging device 70 is provided independently, the imaging device 70 has a table on which printed matter printed by the printing device 100 is placed, and images the printed matter placed on the table.

In addition, it has been described that the imaging device 70 includes a light source 71 and a digital camera 72, and that the light source 71 is provided so that the position at which the imaging region is irradiated with light can be changed. For example, it may be a scanner composed of a light source and an imaging device such as a line sensor. However, in this case, it is not possible to arbitrarily set the viewing conditions when capturing the print image.

The texture map information is not limited to the above-described height map, normal map, roughness map, and environment shielding map. , an environment map that simulates reflections of the surroundings, and the like.

REFERENCE SIGNS LIST 1 printing system 5 printing medium 10 printing unit 11 head unit 12 ink supply unit 13 head 14 head control unit 20 movement unit 30 print control unit 31 PC Interface 32 CPU 33 Memory 34 Drive control unit 35 Movement control signal generation circuit 36 Ejection control signal generation circuit 37 Drive signal generation circuit 40 Scanning unit 41 Carriage 42 Guide shaft 50 Conveyance unit 51 Supply unit 52 Storage unit 53 Conveyance roller 55 Platen 70 Imaging device 71 Light source 72 Digital camera 100 Printing device 110 Image processing Apparatus 111 Operation unit 112 Input unit 113 Display unit 114 Storage unit 115 CPU 116 ASIC 117 DSP 118 Memory 119 PRT interface 120 Communication unit.

Claims (14)

a height map indicating unevenness of the surface, a normal map indicating a normal direction of the surface, and a roughness map indicating roughness of the surface, for reproducing the texture of the surface of the input image by printing; generating a first ink amount map indicating the amount of a first achromatic ink used for reproducing the texture of a printed image, based on at least one texture map among the environment shielding maps indicating the environment shielding state of the surface; process and
generating a second ink amount map indicating the amount of the second ink used for color reproduction of the printed image based on the color map indicating the color of the surface;
and generating print data for controlling a printing device to perform printing based on the generated first ink amount map and second ink amount map. generating rendered image data based on at least one texture map of the height map, the normal map, the roughness map, and the environmental occlusion map; and the color map;
obtaining a first texture parameter based on the brightness distribution of the generated image data;
a step of capturing a print image printed based on the print data and obtaining captured image data;
obtaining a second texture parameter based on the lightness distribution of the acquired imaging data;
a step of comparing the obtained first texture parameter and the second texture parameter and calculating the amount of difference;
generating the print data by correcting the first ink amount map and/or the second ink amount map based on the difference amount when the difference amount exceeds a predetermined threshold. Item 2. The image processing method according to item 1. Based on viewing conditions during rendering based on at least one texture map of the height map, the normal map, the roughness map, and the environmental shielding map, and the color map; based on the print data; 3. The image processing method according to claim 2, wherein observation conditions are set when the printed print image is captured. 4. The image processing method according to claim 2, wherein said texture parameter is skewness and/or standard deviation of lightness distribution. 5. The method according to any one of claims 1 to 4, wherein the first ink, the amount of which is determined based on the height map, is an achromatic ink forming a base of a print image printed with the second ink. The described image processing method. 6. The method according to any one of claims 1 to 5, wherein the first ink, the amount of which is determined based on the normal map, is an achromatic ink forming a base of a print image printed with the second ink. The described image processing method. 7. The method according to any one of claims 1 to 6, wherein the first ink, the amount of which is determined based on the roughness map, is an achromatic ink forming a base of a print image printed with the second ink. The described image processing method. 7. The method according to any one of claims 1 to 6, wherein the first ink, the amount of which is determined based on the roughness map, is a transparent ink forming a surface of a print image printed with the second ink. image processing method. 9. The method according to any one of claims 1 to 8, wherein the first ink, the amount of which is determined based on the environmental shielding map, is an achromatic ink that changes the brightness of the printed image printed with the second ink. The described image processing method. selecting at least one texture map among the height map, the normal map, the roughness map and the environmental occlusion map;
10. The image processing method according to any one of claims 1 to 9, wherein the first ink amount map is generated based on the selected texture map. 11. The image processing method according to claim 1, further comprising the step of correcting or setting the amount of said first ink determined based on said texture map. a height map indicating unevenness of the surface, a normal map indicating a normal direction of the surface, and a roughness map indicating roughness of the surface, for reproducing the texture of the surface of the input image by printing; a communication unit capable of acquiring at least one texture map and a color map indicating the color of the surface;
Based on the obtained texture map, a first ink amount map indicating the amount of the achromatic first ink used for reproducing the texture of the printed image is generated, and based on the obtained color map, color reproduction of the printed image. A second ink amount map indicating the amount of the second ink used for printing is generated, and the printing apparatus is controlled based on the generated first ink amount map and the second ink amount map to perform printing. and an image processing device that generates print data for printing. The calculation unit is
generating rendered image data based on at least one texture map of the height map, the normal map, the roughness map, and the environmental occlusion map; and the color map;
obtaining a first texture parameter based on the brightness distribution of the generated image data;
Acquiring imaging data obtained by imaging a print image printed based on the print data via the communication unit;
Obtaining a second texture parameter based on the brightness distribution of the acquired imaging data,
The obtained first texture parameter and the second texture parameter are compared, and if the amount of difference exceeds a predetermined threshold value, the first ink amount map and/or the 13. The image processing apparatus according to claim 12, wherein the print data is generated by correcting the second ink amount map. The image processing device according to claim 13;
a printing device that prints based on print data generated by the image processing device;
and an imaging device that captures a print image printed by the printing device.

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