JP2016171540A - Print control apparatus and print control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of reducing a memory size for storing a list color conversion table.SOLUTION: A printing control device includes a chromaticity range reception part U1, a list color conversion table generation part U2, and a list printing control part U3, converts an input image D1 with reference to a color conversion table 310 that defines a correspondence relation between input coordinate values (Ri, Gi, Bi) and use amounts (Ci, Mi, Yi, Ki, Lki) of color materials for printing, and performs control to print a converted output image D5. The chromaticity range reception part U1 receives a chromaticity designation range A1 when printing a list image D3 for adjusting the color conversion table 310. The list color conversion table generation part U2 generates a list color conversion table 320 for generating the list image D3 whose chromaticity is changed to the designation range A1 from an original list image D2 based on an input image D1 on the basis of the designation range A1. The list printing control part U3 performs control to convert the original list image D2 with reference to the generated list color conversion table 320 and print an acquired list image D3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a print control apparatus and a print control method that refer to a color conversion table.

  An image forming apparatus such as a printer or a host device such as a personal computer performs control to convert an input image with reference to a color conversion table and print the image after color conversion. The color conversion table includes, for example, RGB (red, green, blue) color coordinate system input coordinate values depending on the monitor, and CMYK (cyan, magenta, yellow, black) ink (color material) used in the printer. Correspondence with usage is defined. The color conversion table is also used for color conversion of gray images having the same RGB input coordinate values. In order to confirm the subtle color of the monochrome image, it is conceivable to test print a monochrome image with a slightly different color.

  The image forming system disclosed in Patent Document 1 does not print a monochrome image, but accepts the settings of a plurality of test color conversion tables and applies each test color conversion table to print a plurality of test output images. The selected test color conversion table is used as the regular color conversion table. Therefore, the test color conversion table and the regular color conversion table have the same number of grid points and the same number of gradations of output values to be stored.

JP 2012-918 A

  In order to improve the quality of a monochrome image, it is necessary to prepare a color conversion table having a large number of grid points and output gradations. On the other hand, when printing a list of test images with slightly different chromaticity, if a color conversion table with a large number of grid points and output gradations is prepared for each test image, a very large memory size is required for list printing control processing. Is required.

  The above problems are not limited to the technique of color-converting an RGB color system input image into a CMYK color system image, and various techniques exist in the same manner.

  In view of the above, one object of the present invention is to provide a technique capable of reducing the memory size for storing the list color conversion table.

In order to achieve one of the above objects, the present invention converts an input image with reference to a color conversion table that defines a correspondence relationship between input coordinate values and the amount of color material used for printing, and outputs after conversion A print control device that performs control to print an image,
A chromaticity range accepting unit for accepting a designated range of chromaticity when printing a list image for adjusting the color conversion table;
A list color conversion table generating unit for generating a list color conversion table for generating a list image whose chromaticity is changed to the specified range from an original list image based on the input image; and
A list print control unit that performs control for converting the original list image with reference to the generated list color conversion table and printing the obtained list image.

  The aspect described above can provide a technique capable of reducing the memory size required for the list printing control process.

  Furthermore, the present invention provides an image forming apparatus, a composite apparatus such as a printing apparatus including a print control apparatus, a print control method including processes corresponding to the above-described units, an image forming method, and a processing method for the composite apparatus including a print control method, In a print control program for causing a computer to realize the functions corresponding to the above-described units, an image forming program, a processing program for a composite device including the print control program, a computer-readable medium on which these programs are recorded, a color conversion table, etc. Applicable. The aforementioned apparatus may be composed of a plurality of distributed parts.

The figure which shows typically the example which forms the actual print image after forming the printed material of the list image based on an input image. FIG. 3 is a diagram schematically illustrating a configuration example of a printing apparatus. The figure which shows the structural example of a host apparatus typically. The figure which shows typically the structural example of an original color conversion table and a color conversion table. The figure which shows the example of the printed matter which has a list image typically. The figure which shows the structural example of the color conversion table for a list typically. The figure which shows typically the example which matches a chromaticity component with the input coordinate value of G and B. FIG. 6 is a flowchart illustrating an example of print control processing performed by a host device. The figure which shows typically the example of the printing color selection screen displayed with a display apparatus, and a color adjustment list range change screen. The figure which shows typically the example of the color adjustment list range change screen displayed by a display apparatus, and a printing color selection screen. The figure which shows the example of a list image typically. The figure which shows the example of the printed matter which has a list image typically. The figure which shows the structural example of a coefficient table typically. 6 is a flowchart illustrating an example of print control processing performed by the printing apparatus. The figure which shows the example of an operation panel typically.

  Embodiments of the present invention will be described below. Of course, the following embodiments are merely examples of the present invention, and all the features shown in the embodiments are not necessarily essential to the means for solving the invention.

(1) Overview of this technology:
First, an overview of the present technology will be described with reference to FIGS.

The print control device U0 illustrated in FIGS. 2 and 3 and the like uses input coordinate values (for example, RGB gradation values Ri, Gi, Bi shown in FIG. 4) and the amount of color material for printing (for example, ink 66) ( For example, the input image D1 is converted with reference to the color conversion table 310 that defines the correspondence with the CMYKLk gradation values Ci, Mi, Yi, Ki, Lki), and the converted output image D5 is printed. . Here, Lk is light black which is an achromatic color having a lower density than K. The print control device U0 includes a chromaticity range reception unit U1, a list color conversion table generation unit U2, and a list print control unit U3. The chromaticity range receiving unit U1 receives a specified range A1 of chromaticity (for example, color coordinates a ^* , b ^* ) when printing the list image D3 for adjusting the color conversion table 310. The list color conversion table generation unit U2 specifies the list color conversion table 320 for generating the list image D3 with the chromaticity changed to the specified range A1 from the original list image D2 based on the input image D1. Generate based on the range A1. The list printing control unit U3 performs control to convert the original list image D2 with reference to the generated list color conversion table 320 and print the obtained list image D3.

  The list color conversion table 320 for generating the list image D3 from the original list image D2 based on the input image D1 is generated based on the specified chromaticity range A1 received by the chromaticity range receiving unit U1. When the user changes the chromaticity specification range A1 of the list image D3 to be printed, a list color conversion table 320 corresponding to the changed specification range A1 is generated, and the list image D3 corresponding to the specification range A1 is printed. Since the list image D3 is dynamically formed according to the designated range A1, the list color conversion table 320 need not be prepared according to the chromaticity range of the list image D3. Therefore, the present technology can reduce the memory size for storing the list color conversion table 320. In addition, since the chromaticity designation range A1 for printing the list image D3 can be changed, the chromaticity of the test image D3a included in the list image D3 can be changed finely, and the chromaticity of the output image D5 can be finely changed. It becomes possible to adjust.

Here, chromaticity means a two-dimensional property of a color obtained by removing a dimension of photometric quantity from a psychophysical color expressed in three dimensions. For example, CIE (International Commission on Illumination) L ^* a ^* b ^* color coordinate a ^* excluding the lightness L ^* dimension from the color ^{space, b *, CIE L * u} * v * color coordinates from the color space excluding the lightness L ^* dimension u ^*, v ^*, and the like. L ^* a ^* b ^* color space L ^* represents a lightness, a ^* and b ^* represent chromaticity which indicates hue and saturation.

  By the way, as shown in FIG. 9 and the like, the chromaticity range receiving unit U1 includes central chromaticity information (for example, input information to the central image selection field 823) indicating the chromaticity at the center of the designated range A1, and the You may receive the input of the range information (for example, the input information to the range selection column 824) showing the range from the center chromaticity represented by center chromaticity information. The list color conversion table generation unit U2 may generate the list color conversion table 320 based on the range represented by the range information from the center chromaticity represented by the center chromaticity information. Since the user only has to specify the center of the chromaticity range to be printed and the range from the center, this mode can easily specify the chromaticity range when printing the list image for color conversion table adjustment. Technology can be provided.

  Although the present technology also includes that the number of test images D3a in the list image is constant, as shown in FIGS. 10 and 11, the list color conversion table generation unit U2 is a number determined by the specified range A1. The list color conversion table 320 for generating the list image D3 including the test images D3a having different chromaticities of Nt from the original list image D2 may be generated based on the specified range A1. The list printing control unit U3 refers to the list color conversion table 320, converts the original list image D2, and prints a list image D3 including the number Nt of test images D3a determined by the designated range A1. May be performed. In this aspect, since the number Nt of test images D3a having different chromaticities included in the list image D3 is a number Nt determined by the designated range A1, a technique capable of easily selecting the chromaticity of the output image is provided. can do.

The number Nt of the test images D3a included in the list image D3 and the specified range A1 are such that the specified range A1 becomes wider as the number Nt of test images D3a included in the list image D3 increases. Good. This aspect provides a technique capable of further facilitating selection of the chromaticity of the output image because the number Nt of test images D3a included in the list image D3 increases as the hue designation range A1 increases. Can do.
In the above relationship, when the specified range of chromaticity can be increased stepwise, the number of test images increases according to the specified stepwise range, and the specified range of chromaticity is continuously increased. If the number of test images can be increased, the number of test images increases step by step.

  The list color conversion table 320 may have a different structure from the color conversion table 310. The difference between the structures of the color conversion table 310 and the list color conversion table 320 is that the number of grid points along the coordinate axis of the input color system is different, and the number of gradations of the usage amount of the color material (66) is different. That the list color conversion table 320 has information that is not in the color conversion table 310. For example, the number N2 of grid points along the coordinate axis (for example, R axis, G axis, and B axis) of the input color system (for example, RGB color system) in the list color conversion table 320 is the color conversion table 310. The number may be smaller than the number N1 of grid points along the coordinate axis of the input color system (see FIGS. 4 and 6). A case where N2 ≧ N1 is also included in the present technology. However, when N2 <N1, the number of grid points of the list color conversion table 320 is reduced, so that the memory size for storing the list color conversion table may be reduced. It becomes possible.

  The number of gradations G2 of the usage amount of the color material (66) in the list color conversion table 320 may be smaller than the number of gradations G1 of the usage amount of the color material (66) in the color conversion table 310. . The case where G2 ≧ G1 is also included in the present technology, but when G2 <G1, the data amount of the usage amount of the printing color material (66) defined in the list color conversion table 320 is reduced. The memory size for storing the color conversion table 320 can be reduced.

As illustrated in FIG. 6, the plurality of components constituting the input color system in the list color conversion table 320 include a lightness component 321 corresponding to lightness and chromaticity to be adjusted (for example, color coordinates a ^* , b). ^* ), And a chromaticity component 322 corresponding to. A correspondence relationship between the lightness component 321 and the usage amount of the color material (66) in the list color conversion table 320 may be generated based on the correspondence relationship in the color conversion table 310. This aspect can improve the color accuracy of the monochrome list image D3.

  As shown in FIGS. 8 to 10 and the like, the printing control apparatus U0 accepts an input for determining an adjustment amount of the chromaticity of the output image D5, and receives input coordinate values (for example, RGB gradation values R0i shown in FIG. 4). , G0i, B0i) and the use amount of the color material for printing (66) (for example, CMYKLk gradation values C0i, M0i, Y0i, K0i, Lk0i), the original color conversion table 300 that defines the correspondence relationship is input as the input. You may further provide the color conversion table adjustment part U5 which produces | generates the said color conversion table 310 by adjusting based on a corresponding adjustment amount. In this aspect, since the color conversion table 310 is adjusted by performing input for determining the amount of adjustment of the chromaticity of the output image D5, the memory size required for the print control process can be reduced.

  The input coordinate value defined in the color conversion table 310 may be a value corresponding to lightness. The color material (66) whose usage is defined in the color conversion table 310 and the list color conversion table 320 may include a chromatic color material (66) (for example, CMY ink). This aspect can provide a print control apparatus suitable for printing the monochrome list image D3.

The present technology is an image forming apparatus that forms an output image D5 from an input image D1 with reference to a color conversion table 310 that defines a correspondence relationship between an input coordinate value and a usage amount of a printing color material (66). There,
A chromaticity range receiving unit U1 that receives a chromaticity specification range A1 when forming the list image D3 for adjusting the color conversion table 310;
List color conversion for generating a list color conversion table 320 for generating a list image D3 whose chromaticity is changed to the specified range A1 from the original list image D2 based on the input image D1 based on the specified range A1 A table generator U2;
A list image forming unit U4 that forms the list image D3 from the original list image D2 with reference to the generated list color conversion table 320 is also provided.

Further, the present technology is an image forming method in which an output image D5 is formed from an input image D1 with reference to a color conversion table 310 that defines a correspondence relationship between an input coordinate value and a usage amount of a printing color material (66). There,
A chromaticity range receiving step of receiving a chromaticity designation range A1 when forming the list image D3 for adjusting the color conversion table 310;
List color conversion for generating a list color conversion table 320 for generating a list image D3 whose chromaticity is changed to the specified range A1 from the original list image D2 based on the input image D1 based on the specified range A1 A table 320 generating step;
A list image formation control step of forming the list image D3 from the original list image D2 with reference to the generated list color conversion table 320.

In these modes, the list image D3 for adjusting the color conversion table is formed by referring to the list color conversion table 320 having a structure different from that of the color conversion table 310 used for actual printing. It becomes possible to reduce the memory size required for processing.
Here, forming the list image includes printing the list image, displaying the list image on a display device, and the like. Of course, forming the output image includes printing the output image, displaying the output image on a display device, and the like.

(2) Specific example of the configuration of a printing system including a printing control apparatus and an image forming apparatus:
FIG. 1 schematically shows an example in which a production monochrome output image D5 is formed on a printing material 410 after a printed material 400 of a list image D3 based on the input image D1 is formed. 2 and 3 schematically show a configuration example of a printing system including the printing apparatus 1 and the host apparatus 100. FIG. FIG. 2 shows a configuration example of a serial printer which is a kind of ink jet printer as the printing apparatus 1 when the printing control apparatus U0 and the image forming apparatus are included. Of course, the inkjet printer to which the present technology can be applied may be a line printer or the like. The printing apparatus to which the present technology can be applied may be an electrophotographic printer such as a laser printer, a copying machine, a facsimile, a multifunction machine having these functions, or the like. FIG. 3 shows an example of the configuration of the host apparatus 100 when a part of the image forming apparatus and the print control apparatus U0 are included.
A monochrome image expresses various chromaticities (hue and saturation) by using achromatic ink together with achromatic ink. The monochrome image includes a sepia tone monochrome image, a warm tone monochrome image, a cool tone monochrome image, and the like.

  First, a configuration example of the printing apparatus 1 including the printing control apparatus U0 and the image forming apparatus will be described with reference to FIG. In the printing apparatus 1 shown in FIG. 2, a controller 10, a RAM (Random Access Memory) 20, a nonvolatile memory 30, a mechanism unit 50, interfaces (I / F) 71 and 72, an operation panel 73, and the like are connected to a bus 80. Thus, information can be input / output to / from each other.

The controller 10 includes a CPU (Central Processing Unit) 11, a resolution conversion unit 41, a color conversion unit 42, a halftone processing unit 43, a rasterization processing unit 44, a drive signal transmission unit 45, and the like. The controller 10 can be configured by SoC (System on a Chip) or the like. The controller 10 constitutes a list color conversion table generation unit U2, a list print control unit U3, and a list image formation unit U4, and constitutes a color conversion table adjustment unit U5 together with the operation panel 73 and the communication I / F 72.
The CPU 11 is a device that mainly performs information processing and control in the printing apparatus 1.

The resolution conversion unit 41 converts the resolution of an image received from the host device 100, the memory card 90, or the like into a set resolution. An image to be converted is represented by RGB data having integer values of 256 gradations of RGB (red, green, blue) such as components of the sRGB color system in each pixel. An input image D1 shown in FIG. 1 is an image before color conversion after resolution conversion. In the input image D1, the pixels PX1 are arranged in the x and y directions orthogonal (different) to each other, and the gradation value (r, g, b) is stored in each pixel PX1. When the input image D1 is a gray image, r = g = b. As internal processing, it is not necessary to store the R gradation value r, the G gradation value g, and the B gradation value b in each pixel PX1, and any one of the gradation values r, g, and b is stored. You may store in each pixel PX1 as a gradation value corresponding to the brightness. Here, the lightness is defined by, for example, the lightness L ^* constituting the CIE L ^* a ^* b ^* color space.
The color conversion unit 42 refers to a production printing LUT (production printing color conversion table) 310 and converts the RGB data of the set resolution into CMYKLk data having CMYKLk gradation values for each pixel. Hereinafter, the color conversion table is also simply referred to as an LUT (Look Up Table).

The halftone processing unit 43 performs a predetermined halftone process such as a dither method, an error diffusion method, or a density pattern method on the gradation values of each pixel constituting the CMYKLk data to obtain the number of gradations of the gradation value. Reduce and generate halftone data. The halftone data is data representing the dot formation status, and may be binary data representing the presence or absence of dot formation, or multi-value data of three or more gradations that can correspond to dots of different sizes such as large, medium, and small dots. But you can.
The rasterization processing unit 44 performs rasterization processing that rearranges the halftone data in the order in which dots are formed by the mechanism unit 50 to generate raster data (pass-unit image data).

The drive signal transmission unit 45 generates a drive signal SG corresponding to the voltage signal applied to the drive element 63 of the head 61 from the raster data and outputs it to the drive circuit 62. For example, if the raster data is “large dot formation”, a drive signal for ejecting ink droplets for large dots is output. If the raster data is “small dot formation”, a drive signal for ejecting ink droplets for small dots is output. Is output.
Each of the units 41 to 45 may be configured by an ASIC (Application Specific Integrated Circuit), and may directly read data to be processed from the RAM 20 or directly write processed data to the RAM 20.

  The mechanism unit 50 controlled by the controller 10 includes a carriage motor 51, a paper feed mechanism 53, a carriage 60, a head 61, and the like. The carriage motor 51 reciprocates the carriage 60 via a plurality of gears and a belt 52 (not shown). The paper feed mechanism 53 transports the printed material 410 in a paper feed direction different from the carriage movement direction. On the carriage 60, for example, a head 61 for ejecting CMYKLk ink droplets (droplets) 67 is mounted. The head 61 includes a drive circuit 62, a drive element 63, and the like. The drive circuit 62 applies a voltage signal to the drive element 63 in accordance with the drive signal SG input from the controller 10. The driving element 63 includes a piezoelectric element that applies pressure to the ink (liquid) 66 in the pressure chamber that communicates with the nozzle 64, a driving element that generates bubbles in the pressure chamber by heat and ejects ink droplets 67 from the nozzle 64, and the like. Can be used. Ink 66 is supplied from an ink cartridge (liquid cartridge) 65 to the pressure chamber of the head 61. The combination of the ink cartridge 65 and the head 61 is provided in each of CMYKLk, for example. The ink 66 in the pressure chamber is ejected as an ink droplet 67 from the nozzle 64 toward the printed material 410 by the driving element 63, and the ink droplet 67 is formed on the printed material 410. By the relative movement of the plurality of nozzles 64 and the substrate 410, an output image D5 corresponding to the input image D1 is formed on the substrate 410.

  The print substrate is a material that holds a print image. The shape is generally rectangular, but there are round shapes (for example, optical disks such as CD-ROM and DVD), triangles, squares, polygons, etc., and at least JIS (Japanese Industrial Standards) P0001: 1998 (paper / paperboard) And pulp and paper products) and all processed products. Resin sheets, metal plates, three-dimensional objects, etc. are also included in the substrate.

The RAM 20 includes a program PRG2 expanded from the program data PRG1, a production printing LUT 310, a list printing LUT (list color conversion table) 320, a designated range A1 of chromaticity (color coordinates a ^* , b ^* ), and the like. Stored. The program PRG2 includes a chromaticity range reception function corresponding to the chromaticity range reception unit U1, a list color conversion table generation function corresponding to the list color conversion table generation unit U2, and a list print control function corresponding to the list print control unit U3. A program for causing the printing apparatus 1 to realize a list image forming function corresponding to the list image forming unit U4 and a color conversion table adjusting function corresponding to the color conversion table adjusting unit U5.
The nonvolatile memory 30 stores program data PRG1, an original LUT (original color conversion table) 300, a coefficient table 380, and the like. As the nonvolatile memory 30, a magnetic recording medium such as a ROM (Read Only Memory) or a hard disk is used. The expansion of the program data PRG1 means that the program is written in the RAM 20 as a program that can be interpreted by the CPU 11.

The card I / F 71 is a circuit that writes data to the memory card 90 and reads data from the memory card 90. The memory card 90 is a nonvolatile semiconductor memory in which data can be written and erased, and stores an image taken by a photographing device such as a digital camera. The image is represented by, for example, pixel values in the RGB color space, and each RGB pixel value is represented by, for example, an 8-bit gradation value from 0 to 255.
The communication I / F 72 is connected to the communication I / F 172 of the host device 100 and inputs / outputs information to / from the host device 100. As the communication I / Fs 72 and 172, USB (Universal Serial Bus) or the like can be used. The host device 100 includes a computer such as a personal computer, a digital camera, a digital video camera, a mobile phone such as a smartphone, and the like.

  The operation panel 73 includes an output unit 74, an input unit 75, and the like, and allows the user to input various instructions to the printing apparatus 1 such as setting whether to print an image in color or monochrome. The output unit 74 includes, for example, a liquid crystal panel (display unit) that displays information corresponding to various instructions and information indicating the state of the printing apparatus 1. The output unit 74 may output the information as a voice. The input unit 75 includes, for example, operation keys (operation input unit) such as a cursor key and a determination key. The input unit 75 may be a touch panel that accepts an operation on the display screen. The operation panel 73 and the communication I / F 72 constitute a chromaticity range reception unit U1 and a color conversion table adjustment unit U5 together with the controller 10.

  Incidentally, at least a part of the print control apparatus U0 and the image forming apparatus may be included in the host apparatus 100. As shown in FIG. 3, when the printer driver 140 is installed in the host device 100, the printer driver 140 converts the host device 100 into a resolution conversion unit 141, a color conversion unit 142, a halftone processing unit 143, a rasterization processing unit 144, and print data. You may make it function as a transmission part 145 etc. Accordingly, the printer driver 140 sets the host device 100 as the chromaticity range receiving unit U1, the list color conversion table generating unit U2, the list printing control unit U3, the list image forming unit U4, and the color conversion table adjusting unit U5. Make it work.

  In the host device 100 shown in FIG. 3, a CPU 111, a ROM 112, a RAM 113, a storage device 114, an input device 115, a communication I / F 172, for example, an external display device 174, and the like are connected to a bus so that information can be input and output between them. ing. The storage device 114 stores an operating system, a printer driver 140, and the like. As the storage device 114, a magnetic storage device such as a hard disk, a nonvolatile semiconductor memory such as a flash memory, or the like can be used. The input device 115 includes an operation input device such as a keyboard or a pointing device. Note that the input device 115 when executing the printer driver constitutes a chromaticity range receiving unit U1 and a color conversion table adjusting unit U5.

The resolution conversion unit 141 converts the resolution of the RGB data to be processed into a set resolution. The color conversion unit 142 converts the RGB data having the set resolution into CMYKLk data having CMYKLk gradation values for each pixel with reference to the actual printing LUT 310. The halftone processing unit 43 performs predetermined halftone processing on the gradation values of each pixel constituting the CMYKLk data to reduce the number of gradations of the gradation values, and generate halftone data. The rasterization processing unit 44 performs rasterization processing for rearranging the halftone data in the order in which dots are formed by the mechanism unit 50 of the printing apparatus 1 to generate raster data. The print data transmission unit 145 transmits print data including raster data to the printing apparatus 1 connected by the communication I / Fs 172 and 72. In this case, the printing apparatus 1 may not include the resolution conversion unit 41, the color conversion unit 42, the halftone processing unit 43, and the rasterization processing unit 44, and the drive signal transmission unit 45 generates the drive signal SG from the raster data. And output to the drive circuit 62.
Of course, when the printing apparatus 1 includes the rasterization processing unit 44, the host apparatus 100 may not include the rasterization processing unit 144. When the printing apparatus 1 further includes the halftone processing unit 43, the host apparatus 100 may not include the halftone processing unit 143. When the printing apparatus 1 further includes the color conversion unit 42, the host apparatus 100 may not include the color conversion unit 142.

FIG. 4 schematically shows an example of generating the actual printing LUT 310 from the original LUT 300 using the coefficients Act, Amt, Ayt corresponding to the chromaticity (color coordinates a ^* , b ^* ) selected by the user. . Here, t is a number for identifying the selected chromaticity, the color coordinate at is the color coordinate a ^* corresponding to the identification number t, and the color coordinate bt is the color coordinate b ^* corresponding to the identification number t. The coefficients Act, Amt, Ayt are associated with the color coordinates at, bt. When the chromaticity is finely adjusted, an enormous memory size is required if an actual printing LUT is prepared in advance according to the chromaticity adjustment. Therefore, in this specific example, the production printing LUT 310 is generated from the original LUT 300 in accordance with the chromaticity adjustment. The specific numerical values shown in the LUTs 300 and 310 in FIG. 4 are merely examples.

  The LUTs 300 and 310 define the correspondence between the input coordinate value and the amount of ink used for printing for each grid point. LUTs 300 and 310 shown in FIG. 4 are data tables for printing a monochrome image, and each component of the RGB color system which is an input color system has the same value. Accordingly, the LUTs 300 and 310 are substantially one-dimensional data tables. The LUT for printing a color image is usually a three-dimensional data table, and the number of grid points along the RGB color system coordinate axes (R axis, G axis, and B axis) is input in order to reduce the data size. The number of gradations is smaller than the coordinate value. The one-dimensional LUTs 300 and 310 adjust the number of grid points N1 to the number of gradations of the input coordinate value (for example, 256 that can be expressed by 8 bits) in order to improve the quality of the formed monochrome image. As a result, color conversion can be performed with reference to the actual printing LUT 310 without performing an interpolation operation, and high gradation and high-speed processing are possible. Also, the number of gradations G1 of the output coordinate values corresponding to the amount of ink used in the LUTs 300 and 310 is larger than the number of gradations (for example, 256) of the output coordinate values in the LUT for color image printing (for example, 16 bits). 65,000) that can be expressed in Thereby, highly accurate color adjustment is possible.

The original LUT 300 prescribes the correspondence between the input coordinate values R0i, G0i, B0i and the output coordinate values C0i, M0i, Y0i, K0i, Lk0i. Here, the variable i is an integer from 0 to 255. As the internal processing, a data table in which the output coordinate values C0i, M0i, Y0i, K0i, and Lk0i are stored in an address corresponding to any one of R0i, G0i, and B0i may be used as the original LUT 300.
It is assumed that the actual printing LUT 310 defines a correspondence relationship between the input coordinate values Ri, Gi, Bi and the output coordinate values Ci, Mi, Yi, Ki, Lki. As the internal processing, a data table in which the output coordinate values Ci, Mi, Yi, Ki, and Lki are stored in an address corresponding to any one of Ri, Gi, and Bi may be used as the LUT 310. In this specific example, when the production printing LUT 310 is generated based on the original LUT 300, only the chromatic color output coordinate values Ci, Mi, Yi are generated, and Ki = K0i and Lki = Lk0i.

The coefficients Act, Amt, and Ayt are data for generating the output coordinate values Ci, Mi, and Yi of the actual printing LUT 310 from the output coordinate values C0i, M0i, and Y0i of the original LUT 300 according to the chromaticity selected by the user. is there. For example, assuming that 0 <Act ≦ 1, 0 <Amt ≦ 1, and 0 <Ayt ≦ 1,
Ci = Act × C0i
Mi = Amt × M0i
Yi = Ayt × Y0i
The output coordinate values Ci, Mi, Yi can be calculated by the following formula.
Note that the coefficients Act, Amt, and Ayt can be made larger than 1 in accordance with the output coordinate values C0i, M0i, and Y0i.

By the way, the printing control apparatus U0 is for forming the printed material 400 (see FIG. 5) of the list image D3 so that the subtle color of the monochrome output image D5 formed on the substrate 410 can be confirmed. Each part U1-U3 is provided. A printed material 400 shown in FIG. 5 is a printed image 410 in which a list image D3 with chromaticity (a ^* , b ^* ) changed to a specified range A1 is printed. As described above, the color coordinates a ^* and b ^* are color components constituting the CIE L ^* a ^* b ^* color space. The list image D3 includes a plurality of test images D3a having different chromaticities. The plurality of test images D3a are centered on the center image D3d of chromaticity (at, bt), for example, the color coordinate a ^* increases by a predetermined value Δa in order from left to right, and the color coordinate b ^{* in} order from bottom to top ^. Are arranged vertically and horizontally so as to increase by a predetermined value Δb. An identification number is printed on the upper left of each test image D3a. For convenience, non-printed chromaticity is shown below each test image D3a.

The chromaticity range receiving unit U1 shown in FIG. 1 receives a specified range A1 of chromaticity (a ^* , b ^* ) when printing the list image D3 for adjusting the actual printing LUT 310. The designated range A1 corresponds to the chromaticity range of the test image D3a included in the list image D3 as shown in FIG. 5, for example, the chromaticity (at, bt) of the center image D3d and the chromaticity (at , Bt) (in the example shown in FIG. 5, 2Δa and 2Δb). The present technology has a feature that the designated range A1 can be changed according to a user's desire.

  The list color conversion table generation unit U2 shown in FIG. 1 generates a list print LUT (list color conversion table) 320 based on the accepted designated range A1. The list printing LUT 320 is an LUT for generating a list image D3 whose chromaticity is changed to a specified range A1 from an original list image D2 based on the input image D1, and is dynamically formed according to the specified range A1. .

The list printing control unit U3 shown in FIG. 1 first generates an original list image D2 that is a list of test images D2a having different chromaticities (a ^* , b ^* ) based on the input image D1. In each image D2a, pixels are arranged in the x and y directions in the same manner as the input image D1, and RGB gradation values are stored in each pixel. In this specific example, the gradation value r of the input image D1 is stored in the pixel of the test image D2a as the gradation value of R, and the gradation value representing the chromaticity of each image D3a in the printed matter 400 is the gradation values of G and B. The value is stored in the pixel of the test image D2a. FIG. 1 shows that the gradation value corresponding to the color coordinate a ^* is stored as the G gradation value, and the gradation value corresponding to the color coordinate b ^* is stored as the B gradation value. ing. Assuming that gradation values r, g1, and b1 are stored in pixels of a test image D2b and gradation values r, g2, and b2 are stored in pixels of another test image D2c, g1, g2 are a ^*. And b1 and b2 are tone values corresponding to b ^* .

Each test image D2a of the original list image D2 is preferably reduced from the input image D1 so that a plurality of test images D2a are formed on one substrate 410. The input image D1 can be reduced by various image processing methods. For example, when the pixel PX1 is sampled from the input image D1 so that every m pixels in the x direction (m is an integer of 2 or more) and every n pixels in the y direction (n is an integer of 2 or more), A test image D2a reduced to 1 / m and 1 / n in the y direction is generated. Further, even if the pixel values are averaged in units of m pixels in the x direction and n pixels in the y direction, a test image D2a reduced to 1 / m in the x direction and 1 / n in the y direction is generated. Is done. Of course, each test image D2a also stores a gradation value representing chromaticity.
Note that the list printing control unit U3 of this specific example adds a number for identifying the test image D2a to the upper left of each test image D2a in accordance with the list image D3 of the printed matter 400 shown in FIG.

  When the original list image D2 is generated, the list printing control unit U3 refers to the list printing LUT 320 having a structure different from that of the actual printing LUT 310 and performs color conversion on the original list image D2. As shown in FIG. 1, each image D3a of the converted list image D3 has pixels arranged in the x and y directions as in the original list image D2, but each pixel stores a CMYKLk gradation value. The In FIG. 1, the gradation values r, g1, b1 stored in the test image D2b before conversion are converted into gradation values c1, m1, y1, k, lk and stored in the test image D3b. It is shown that the gradation values r, g2, b2 stored in the image D2c are converted into gradation values c2, m2, y2, k, lk and stored in the test image D3c.

FIG. 6 schematically shows a structural example of the list printing LUT 320. It should be noted that the specific numerical values shown in the list printing LUT 320 are merely examples. The list printing LUT 320 defines the correspondence between the input coordinate values Rj, Gj, Bj and the output coordinate values Cj, Mj, Yj, Kj, Lkj for each grid point. Here, the variable j is a number for identifying the grid point of the list printing LUT 320. The plurality of components constituting the input color system in the list printing LUT 320 include a lightness component 321 corresponding to the lightness and a chromaticity component 322 corresponding to the chromaticity to be adjusted. In this specific example, the gradation value r of the test image D2a is made to correspond to the R input coordinate value Rj of the list printing LUT 320, and the gradation value g1, g2,. In correspondence with the coordinate value Gj, the gradation values b1, b2,... Of the test image D2a are made to correspond to the input coordinate value Bj of B of the list printing LUT 320. That is, the list printing LUT 320 is a three-dimensional data table in which the pseudo RGB color system is an input color system, the R input coordinate value Rj is a gradation value corresponding to lightness, and the G input coordinate The value Gj is a gradation value corresponding to the color coordinate a ^* , and the B input coordinate value Bj is a gradation value corresponding to the color coordinate b ^* . The output coordinate values Cj, Mj, Yj, Kj, and Lkj are set so that chromaticity (a ^* , b ^* ) corresponding to the input coordinate values Gj, Bj is given to the test image D3a after color conversion. .

  Originally, RGB input coordinate values Rj, Gj, and Bj in a monochrome image LUT should be Rj = Gj = Bj. In this specific example, the roles of the input coordinate values Rj, Gj, and Bj are changed, the input coordinate value Rj is used as a gradation value corresponding to lightness, and the input coordinate values Gj and Bj are used as gradation values for switching color adjustment. A list printing LUT 320 including a plurality of simplified production printing LUTs 310 is prepared. By creating the original list image D2 so as to correspond to the list printing LUT 320, the original list image D2 is collectively color-converted with reference to one list printing LUT 320, and the list image D3 is printed on the substrate 410. And high-speed processing is possible.

Since the combination of the input coordinate values Gj and Bj corresponds to the chromaticity to be adjusted, the list printing LUT 320 can be divided into regions according to the combination of the input coordinate values Gj and Bj. The output coordinate values Cj, Mj, Yj, Kj, and Lkj of each area (for example, the areas R1 to R5 shown in FIG. 6) of the list printing LUT 320 are the chromaticities of the areas with the number t as the identification number of the area (R1 to R5). It can be determined based on a method similar to the method of generating the actual printing LUT 310 from the original LUT 300 using the coefficients Act, Amt, Ayt corresponding to (a ^* , b ^* ). The difference from the generation of the actual printing LUT 310 is that the number N2 of grid points for obtaining the output coordinate value is smaller than the number N1 of grid points of the actual printing LUT 310, and the gradation number G2 of the output coordinate value is the output of the actual printing LUT 310. This is less than the number of gradations G1 of coordinate values.
For example, for the output coordinate value of the region R1 of (Gj, Bj) = (0, 0) of the list printing LUT 320, both the chromaticity (a ^* , b ^* ) of the image after color conversion are within the specified range A1. The minimum coefficients Act, Amt, Ayt can be determined by applying them to the original LUT 300. In this case, for example, output coordinate values C0i, M0i, Y0i, K0i, Lk0i (gradation number G1) corresponding to the input coordinate values R0i = G0i = B0i = Rj at N2 locations are extracted from the original LUT 300, and the output coordinate value C0i is extracted. , M0i, Y0i are multiplied by the coefficients Act, Amt, Ayt, and the output coordinate values Act × C0i, Amt × M0i, Ayt × Y0i, K0i, Lk0i after applying the coefficients are expressed as the number of gradations G2 (G2 <G1 ) Output coordinate values Cj, Mj, Yj, Kj, Lkj.
Cj = (Act × C0i) × G2 / G1
Mj = (Amt × M0i) × G2 / G1
Yj = (Ayt × Y0i) × G2 / G1
Kj = K0i × G2 / G1
Lkj = Lk0i × G2 / G1
When the obtained output coordinate values Cj, Mj, Yj, Kj, and Lkj are associated with the input coordinate values (Rj, Gj, Bj) = (Rj, 0, 0), a list printing LUT 320 for the region R1 is generated. .

Regarding the output coordinate value of the region R2 of (Gj, Bj) = (0, 255) of the list printing LUT 320, a ^* of the image after color conversion is minimized within the designated range A1, and b ^* is within the designated range A1. The coefficients Act, Amt, and Ayt to be maximized can be determined by applying them to the original LUT 300. Also in this case, for example, output coordinate values C0i, M0i, Y0i, K0i, Lk0i (gradation number G1) corresponding to the input coordinate values R0i = G0i = B0i = Rj at N2 locations are extracted from the original LUT 300, and the output coordinate values are extracted. C0i, M0i, and Y0i are multiplied by coefficients Act, Amt, and Ayt, and the output coordinate values after applying the coefficients are set to output coordinate values Cj, Mj, Yj, Kj, and Lkj of the gradation number G2 (G2 <G1). . When the obtained output coordinate values Cj, Mj, Yj, Kj, Lkj are associated with the input coordinate values (Rj, Gj, Bj) = (Rj, 0, 255), a list printing LUT 320 for the region R2 is generated. .
As for the output coordinate value of the region R3 of (Gj, Bj) = (128, 128) of the list printing LUT 320, the coefficient that makes the chromaticity (a ^* , b ^* ) of the image after color conversion the center of the designated range A1 It can be determined by applying Act, Amt, Ayt to the original LUT 300. The output coordinate values of the regions R4 and R5 can be similarly determined.

As described above, the input coordinate value Rj and the output coordinate value Cj, Mj, Yj in the list printing LUT 320 based on the correspondence relationship of each production printing LUT according to the coefficients Act, Amt, Ayt corresponding to the chromaticity. , Kj, and Lkj are generated. The present technology is characterized in that the correspondence between the input coordinate value Rj and the output coordinate value Cj, Mj, Yj, Kj, Lkj is dynamically generated according to the chromaticity designation range A1.
In order to generate the list printing LUT 320, an original list printing LUT in which output coordinate values (C0j, M0j, Y0j, K0j, and Lk0j) are set to the number of gradations G2 may be prepared. In this case, the output coordinate values C0j, M0j, Y0j of the original list printing LUT are multiplied by the coefficients Act, Amt, Ayt corresponding to the chromaticity of each area of the list printing LUT 320 to obtain the output coordinate values Cj, Mj, Yj. The list printing LUT 320 may be generated.

  The three-dimensional list printing LUT 320 has an enormous data size when the number N2 of grid points along the pseudo RGB coordinate axes is matched with the number N1 of grid points of the actual printing LUT 310. Therefore, the number of grid points N2 is set to a number smaller than N1 (for example, 17), the data size of the list printing LUT 320 is suppressed, and the memory size for storing the list printing LUT 320 is reduced. In the list printing LUT 320 shown in FIG. 6, the grid points along the RGB coordinate axes are 17 points corresponding to the input coordinate values 0, 16, 32,. Here, the number of grid points along the RGB coordinate axes is smaller than the grid point number N1 of the production printing LUT 310 means that the number of grid points along the R axis is smaller than N1 and the grid points along the G axis. Is smaller than N1, and the number of lattice points along the B-axis is smaller than N1.

The number of regions (e.g., R1 to R5) which can be assigned to Printable LUT320 becomes N2 ^2. Therefore, the number Nt of test images D3a included in the list image D3 is N2 ^{2 at} the maximum. This technique, it is possible to change the specified range A1 of chromaticity, it is possible to adjust the chromaticity of the output image D5 in the substantially equivalent to see the number of test images D3a more than N2 ² fineness .

  The gradation number G2 of the output coordinate values Cj, Mj, Yj, Kj, and Lkj corresponding to the ink usage in the list printing LUT 320 is the output coordinate values Ci, Mi, Yi, Ki, and Lki of the actual printing LUT 310. The number is smaller than the number of gradations (for example, 256 that can be expressed by 8 bits). This also reduces the data size of the list printing LUT 320 and reduces the memory size for storing the list printing LUT 320.

FIG. 7 schematically shows an example in which chromaticity components (a ^* , b ^* ) are associated with the input coordinate values Gj, Bj. The list printing LUT 320 is dynamically generated according to the specified chromaticity range A1. FIG. 7 shows an example in which the designated range A1 is changed in the order of the designated ranges A11, A12, and A13 on the a ^* b ^* coordinate plane. The first designated range A11 is shown by a rectangular solid line centered on a point O1 of (a ^* , b ^* ) = (0, 0). The next designated range A12 is indicated by a rectangular broken line that is the same as the center point O1 of the first designated range A11 and extends from the first designated range A11. The last designated range A13 is indicated by a thick bold line centered on the point O2 moved from the point O1. In the lower part of FIG. 7, the first designated range A13 is shown in an enlarged manner, and the positions corresponding to the regions R1 to R5 of the list printing LUT 320 are also shown. In the example of FIG. 7, the specified range A13 of amin ≦ a ^* ≦ amax and bmin ≦ b ^* ≦ bmax is included in the input coordinate values Gj, Bj out of the entire chromaticity range A0 that can be expressed by the CMY chromatic ink. Is associated with. Here, amin <amax and bmin <bmax, amin is associated with Gj = 0, amax is associated with Gj = 255, bmin is associated with Bj = 0, and bmax is associated with Bj = 255.

Since each test image D2a of the original list image D2 stores G and B gradation values corresponding to the chromaticity (a ^* , b ^* ), the original list image D2 is referred to by referring to the three-dimensional list printing LUT 320. The list image D2 can be color-converted collectively. Accordingly, the list printing control process is quickly performed.

  When the original list image D2 is color-converted with reference to the list printing LUT 320, the list print control unit U3 performs control to print the converted list image D3. As a result, a printed material 400 in which a list image D3 in which test images D3a having different chromaticities are arranged vertically and horizontally is provided on the printed material 410 is formed. The user of the printing apparatus 1 can set the chromaticity of the actual output image D5 by looking at the list image D3.

(3) Description of print control process, action and effect:
FIG. 8 shows an example of a print control process including a print control method and an image forming method implemented by the host device 100 shown in FIG. Here, step S116 corresponds to the chromaticity range receiving unit U1, step S118 corresponds to the list color conversion table generation unit U2, and steps S102 to S112 correspond to the list print control unit U3 and the list image forming unit U4. Steps S112 and S120 correspond to the color conversion table adjustment unit U5. Hereinafter, the description of “step” is omitted.

  For example, when the host apparatus 100 accepts an operation for printing an image stored in the RAM 113 from a user, the host apparatus 100 starts a print control process. First, the host device 100 converts the resolution of the image stored in the RAM 113 by the resolution conversion unit 141, and branches the process according to the printing method (S102). For example, when an operation for performing color printing of an image is performed, the host apparatus 100 performs color control on the input image with reference to a color printing LUT (not shown), and performs control for printing the converted image. When an operation for monochrome printing of an image is performed, processing is divided depending on whether the image is a color image or a monochrome image. When monochrome printing a color image, the host device 100 converts the color image into a gray image (S104), and advances the processing to S106. When the pixel value of the color image is (r0, g0, b0) and the pixel value of the gray image after conversion is (r, g, b), the conversion to the gray image is, for example, the calculation formula r = g = b = (R0 + g0 + b0) / 3. When monochrome printing a gray image, the host device 100 proceeds directly to step S106.

In S106, the original list image D2 is generated based on the gray input image D1 as shown in FIG. For example, the host apparatus 100 reduces the input image D1, arranges the obtained reduced images at the positions of the test images D2a, and sets the G gradation values of the reduced images arranged in a matrix as gradation values corresponding to a ^*. And the B gradation value of each reduced image is replaced with a gradation value corresponding to b ^* . The gradation values of G and B to be replaced are values corresponding to the position of the test image D2a. FIG. 1 shows that the gradation values r, g1, and b1 are stored in the pixels of the test image D2b, and the gradation values r, g2, and b2 are stored in the pixels of another test image D2c. For example, when generating the central image of the original list image D2, G and B are matched with the input coordinate values (Rj, Gj, Bj) = (Rj, 128, 128) of the region R3 of the list printing LUT 320 shown in FIG. Are all replaced with 128. When generating the test image D2a that minimizes the chromaticity (a ^* , b ^* ) of the image after color conversion within the specified range A1, the input coordinate value (Rj, Gj, Bj) = (Rj, In accordance with (0, 0), both G and B pixel values are replaced with 0. When generating a test image D2a that minimizes a ^* of the image after color conversion within the designated range A1 and minimizes b ^* within the designated range A1, the input coordinate value (Rj, Gj, Bj) of the region R2 = In accordance with (Rj, 0, 255), the G pixel value is replaced with 0, and the B pixel value is replaced with 255.
As described above, the original list image D2 that is a list of images D2a having different chromaticities (a ^* , b ^* ) is generated.

In S <b> 108, the original list image D <b> 2 is color-converted with reference to the list printing LUT 320. The list printing LUT 320 when performing the processing of S108 for the first time may be a list printing LUT prepared in advance, or may be a list printing LUT generated based on the first designated range A11. A method for generating the list printing LUT 320 based on the designated range A1 will be described later.
Since the combination of G and B gradation values stored in each test image D2a corresponds to the chromaticity to be adjusted, different areas of the list printing LUT 320 are referred to for each test image D2a. For example, the pixel values (r, 128, 128) stored in the test image D2a before conversion are referred to the area R3 of the list printing LUT 320 shown in FIG. 6, and the gradation values Cj, Mj, Yj, Kj, Converted to Lkj. If there is no R pixel value r in the R input coordinate value of the list printing LUT 320, conversion is performed by interpolation using output coordinate values corresponding to a plurality of R input coordinate values in the vicinity of the pixel value r. Subsequent gradation values Cj, Mj, Yj, Kj, Lkj may be calculated. The interpolation calculation may be a one-dimensional interpolation calculation, and linear interpolation or non-linear interpolation may be performed.

  In S110, the converted list image D3 is converted into halftone data by the halftone processing unit 143, the halftone data is rearranged by the rasterizing processing unit 144, and the print data including the generated raster data is transmitted to the printing apparatus 1. To do. In this way, control for printing the list image D3 is performed. The printing apparatus 1 that has received the print data generates a drive signal SG corresponding to the raster data by the drive signal transmission unit 45 and outputs it to the drive circuit 62. The mechanism unit 50 prints a list image D3 as shown in FIG. An identification number is assigned to each test image D3a of the list image D3.

  In S112, a print color selection screen 810 as shown in the upper part of FIG. 9 is displayed on the display device 174. The print color selection screen 810 shown in FIG. 9 includes a test image 811 corresponding to each test image D3a shown in FIG. 5, a test image D3a selection field 813 when the output image D5 is actually printed, a production print execution button 814, A color adjustment range change button 815, a cancel button 816, and the like are provided. Each test image 811 has an identification number printed on the upper left of the test image D3a of the printed matter 400. The chromaticity of each test image 811 may be changed in accordance with the test image D3a of the printed material 400. Of course, the chromaticity of each test image 811 may not be accurate. The plurality of test images 811 include the test image 812 selected in the image selection field 813. The test image 812 corresponds to the chromaticity of the output image D5 when performing actual printing. The test image 812 may be displayed so as to be distinguished from the remaining test images 811. The image selection field 813 receives an operation input for selecting the identification number of the test image 811 using the input device 115. Accepting an input in the image selection field 813 corresponds to accepting an input for determining an adjustment amount (coefficient) of the chromaticity of the output image D5.

  The host device 100 branches the process according to the operation of the buttons 814 to 816 by the input device 115 (S114). When the host device 100 accepts an operation on the production print execution button 814, the host device 100 advances the processing to S120 and starts production printing control processing. When the host device 100 accepts an operation on the color adjustment range change button 815, the host device 100 displays a color adjustment list range change screen 820 as shown in the lower part of FIG. 9 on the display device 174 (S116). Note that the host device 100 may end the print control process upon receiving an operation on the cancel button 816.

  In the color adjustment list range change screen 820 shown in FIG. 9, the test image 821 corresponding to each test image D3a shown in FIG. 5, the selection field 823 of the center image D3d when the list image D3 is printed, and the list image D3 are printed. In this case, a range selection column 824 from the center image D3d, a list print execution button 825, a cancel button 826, and the like are provided. Each test image 821 has an identification number printed on the upper left of the test image D3a of the printed matter 400. The chromaticity of each test image 821 may be changed according to the test image D3a of the printed material 400. Of course, the chromaticity of each test image 821 may not be accurate. The plurality of test images 821 include the test image 822 selected in the center image selection field 823. The test image 822 corresponds to the center image D3d when the list is printed. The test image 822 may be displayed so as to be distinguished from the remaining test images 821.

  The center image selection field 823 accepts an operation input for selecting the identification number of the test image 821 by the input device 115. The received identification number corresponds to central chromaticity information representing the central chromaticity (at, bt) of the designated range A1. A plurality of test images 821 shown in FIG. 9 have test images with identification numbers 1 to 4 and 6 to 9 with chromaticities varied by ± Δa and ± Δb around the test image with identification number 5. Therefore, on the color adjustment list range change screen 820 shown in FIG. 9, the chromaticity (at, bt) of the center of the new designated range A1 can be designated in the range of ± Δa and ± Δb.

  The range selection field 824 receives an operation input for selecting the chromaticity range to be changed from the new center image D3d by the input device 115. The accepted range (referred to as W) corresponds to range information representing a range from the center chromaticity (at, bt) represented by the center chromaticity information. FIG. 11 schematically shows a list image D3 of the number of test images Nt formed on the substrate 410 in accordance with the accepted range W. The number Nt of test images D3a included in the list image D3 and the specified range A1 have a relationship in which the specified range A1 becomes wider as the number Nt of test images D3a included in the list image D3 increases.

When the range 1 is accepted, a list image D31 in which Nt = 3 × 3 test images D3a having different chromaticities of ± Δa and / or ± Δb around the center image D3d is printed. When the range 2 is accepted, a list image D32 is printed in which Nt = 5 × 5 test images D3a having different chromaticities in a range of ± 2Δa and ± 2Δb with the central image D3d as a base point. When the maximum range 5 is accepted, a list image D35 in which test images D3a with different chromaticity Nt = 11 × 11 in a range of ± 5Δa and ± 5Δb with the central image D3d as a base point is printed. When the ranges 3 and 4 are accepted, the list images D33 and D34 are printed. The test images D3a are arranged with a chromaticity difference Δa in the a ^* axis direction and arranged with a chromaticity difference Δb in the b ^* axis direction. In general, when the range W is accepted, a list image D3 is printed in which Nt = (2W + 1) × (2W + 1) test images D3a having different chromaticities in a range of ± WΔa and ± WΔb with the central image D3d as a base point are printed. Is done.

  The size of each test image D3a formed on the substrate 410 may vary according to the range W as illustrated in FIG. In the upper part of FIG. 12, a printed product 400 of a list image D31 having a test image D3a of Nt = 3 × 3 is shown. In the lower part of FIG. 12, a printed material 400 of a list image D33 having a test image D3a with Nt = 7 × 7 is shown. Although not shown, the size of the test image D3a included in the list image D32 having the 5 × 5 test image D3a is smaller than the test image D3a included in the list image D31, and the test image included in the list image D33. It shall be larger than D3a. Thus, if each test image D3a is enlarged as the designated range A1 (range W) becomes narrower, the color of the test image D3a can be confirmed more easily.

  Note that the host device 100 may return to the print color selection screen 810 upon accepting an operation on the cancel button 826.

  When the host device 100 accepts an operation on the list print execution button 825, the host device 100 accepts the center chromaticity (at, bt) corresponding to the test image 822 of the identification number accepted in the center image selection field 823 in the range selection field 824. The list printing LUT 320 is generated based on the range W (S118). Since the chromaticity of each test image D3a constituting the list image D3 is obtained from the central chromaticity (at, bt) and the range W, the output coordinate values Cj, Mj, Yj, Kj, It can be determined based on the coefficients Act, Amt, Ayt that make Lkj the chromaticity of the test image D3a.

FIG. 13 shows coefficients Acr, Amr, and Ayr that make the output coordinate values Cj, Mj, Yj, Kj, and Lkj of each area of the list printing LUT 320 chromaticity of the test image D3a as representative points Pr in the a ^* b ^* coordinate plane. 3 schematically shows an example of the structure of a coefficient table 380 that defines the above. Here, the variable r means a number for identifying the representative point Pr. The coefficient table 380 is an information table that associates the chromaticity (ar, br) of the representative point Pr with the coefficients Acr, Amr, Ayr. Again, the output coordinate values Cj, Mj, Yj, Kj, and Lkj of each area (for example, the areas R1 to R5 shown in FIG. 6) of the list printing LUT 320 are the chromaticities (a ^* , b ^* ) of the test image D3a. The corresponding coefficients Acr, Amr, Ayr can be determined by applying them to the original LUT 300. The output coordinate values Cj, Mj, Yj, Kj, and Lkj of the list printing LUT 320 are calculated as follows assuming that 0 <Acr ≦ 1, 0 <Am ≦ 1, and 0 <Ayr ≦ 1, for example. be able to.
Cj = (Acr × C0i) × G2 / G1
Mj = (Amr × M0i) × G2 / G1
Yj = (Ayr × Y0i) × G2 / G1
Kj = K0i × G2 / G1
Lkj = Lk0i × G2 / G1

For example, when the chromaticity (a ^* , b ^* ) of a certain test image D3a is the chromaticity (ar, br) of the representative point Pr, the coefficients Acr, Amr, Ayr corresponding to the chromaticity (ar, br) are coefficients. Read from table 380. In this case, output coordinate values C0i, M0i, Y0i, K0i, Lk0i (number of gradations) associated with the input coordinate values R0i = G0i = B0i = Rj at N2 locations corresponding to the chromaticity of the test image D3a from the original LUT 300. G1) is extracted, and the output coordinate values C0i, M0i, Y0i are multiplied by the coefficients Act, Amt, Ayt, and the obtained output coordinate values Act × C0i, Amt × M0i, Ayt × Y0i, K0i, Lk0i are used as the number of gradations G2. The output coordinate values Cj, Mj, Yj, Kj, and Lkj of (G2 <G1) may be set. By associating the obtained output coordinate values Cj, Mj, Yj, Kj, and Lkj with the input coordinate values (Rj, Gj, Bj), a list printing LUT 320 of the area corresponding to the chromaticity of the test image D3a is generated. The

If the chromaticity (a ^* , b ^* ) of the test image D3a to be printed is not in the chromaticity (ar, br) of the coefficient table 380, a plurality of chromaticities (a ^* , b ^* ) near the chromaticity (a ^* , b ^* ) of the test image D3a The coefficients Acr, Amr, Ayr may be obtained by interpolation calculation using the coefficient corresponding to the representative point. The output coordinate values Cj, Mj, Yj, Ki, and Lki of the list printing LUT 320 can be determined by applying the obtained coefficients Acr, Amr, and Ayr to the above formula. Of course, the interpolation calculation may be a one-dimensional interpolation calculation, linear interpolation or non-linear interpolation may be performed.
When the chromaticity of a part of the test images D3a is out of the interpolation range of the representative point Pt by changing the center image D3d and the range W, the part of the test images D3a is not formed. The coefficients Acr, Amr, Ayr may not be obtained.

In order to generate the list printing LUT 320, an original list printing LUT in which the output coordinate values C0j, M0j, Y0j, K0j, and Lk0j are set to the gradation number G2 may be prepared. In this case, the output coordinate values Cj are obtained by multiplying the output coordinate values C0j, M0j, Y0j of the original list printing LUT by the coefficients Acr, Amr, Ayr applied to the area corresponding to the chromaticity of each test image D3a in the list printing LUT 320. , Mj, Yj, the list printing LUT 320 may be generated.
As described above, the list printing LUT 320 is generated based on the range W received in the range selection field 824 from the center image D3d of the identification number received in the center image selection field 823.

  After that, the host apparatus 100 performs color conversion on the original list image D2 with reference to the newly generated list printing LUT 320 (S108), and performs halftone processing and rasterization processing on the converted list image D3 for printing. Data is transmitted to the printing apparatus 1 (S110). For example, assume that the test image 822 with the identification number 1 is selected as in the color adjustment list range change screen 820 shown in the upper part of FIG. 10, the range W = 2 is selected, and the list print execution button 825 is operated. In this case, for list printing to form a 5 × 5 test image D3a in which the chromaticity is in the range of ± 2Δa and ± 2Δb from the chromaticity (at, bt) corresponding to the original identification number 1 test image D3a. An LUT 320 is generated, and a list image D3 is printed according to the list printing LUT 320 as shown in FIG. Since the original list image is composed of 3 × 3 test images centered on the center image corresponding to the test image 821 with the identification number 5 in the upper part of FIG. 10, the new center image D3d is derived from the original center image. The chromaticity is changed by -Δa and + Δb, and the range from the center image D3d is changed from ± Δa and ± Δb to ± 2Δa and ± 2Δb. As described above, the present technology has a feature that the list image D3 is dynamically formed in accordance with the chromaticity designation range A1.

  In S112, a print color selection screen 810 as shown in the lower part of FIG. In the print color selection screen 810 shown in FIG. 10, the chromaticity of the central image D3d corresponding to the identification number 13 is changed by −Δa and + Δb from the chromaticity of the central image corresponding to the identification number 5 shown in the upper part of FIG. The range from the center image D3d is changed from ± Δa and ± Δb to ± 2Δa and ± 2Δb.

  When the processes of S108 to S118 are repeated and the production print execution button 814 is operated on the print color selection screen 810, the processes of S120 to S124 are performed. First, the host device 100 adjusts the chromaticity (at ′, bt ′) of the test image D3a corresponding to the identification number selected in the image selection field 813 (the coefficients are Act ′, Amt ′, Ayt ′). Based on the above, the original LUT 300 is adjusted to generate the actual printing LUT 310 (S120).

The actual printing LUT 310 can be generated with reference to the coefficient table 380 shown in FIG. For example, when there is a representative point corresponding to the chromaticity (at ′, bt ′) of the test image D3a corresponding to the identification number selected in the image selection field 813, it corresponds to the chromaticity (at ′, bt ′). The coefficients Act ′, Amt ′, and Ayt ′ are stored in the coefficient table 380. in this case,
(Ci, Mi, Yi, Ki, Lki)
= (Act ′ × C0i, Amt ′ × M0i, Ayt ′ × Y0i, K0i, Lk0i)
Thus, the output coordinate values Ci, Mi, Yi, Ki, and Lki of the production printing LUT 310 can be obtained. When coefficients corresponding to chromaticity (at ′, bt ′) are not stored in the coefficient table 380, coefficients corresponding to a plurality of representative points in the vicinity of chromaticity (at ′, bt ′) are used. The coefficients Act ′, Amt ′, and Ayt ′ may be obtained by interpolation calculation. By applying the obtained coefficients Acr, Amr, Ayr to the above-described calculation formula, the output coordinate values Ci, Mi, Yi of the actual printing LUT 310 can be calculated. Of course, the interpolation calculation may be a one-dimensional interpolation calculation, linear interpolation or non-linear interpolation may be performed.

  In S122, the color conversion unit 142 performs color conversion on the RGB color system input image D1 with reference to the production printing LUT 310. Thereby, the input coordinate value Ri = Gi = Bi is converted into the output coordinate value Ci, Mi, Yi, Ki, Lki, and the gradation value r = g = b of each pixel of the input image D1 becomes the gradation value of CMYKLk. Converted.

  In S124, the color-converted image is converted into halftone data by the halftone processing unit 143, the halftone data is rearranged by the rasterization processing unit 144, and the print data including the generated raster data is transmitted to the printing apparatus 1. . The printing apparatus 1 that has received the print data generates a drive signal SG corresponding to the raster data by the drive signal transmission unit 45 and outputs it to the drive circuit 62. The mechanism unit 50 forms an output image D5 on the substrate 410 as shown in FIG. 1 according to the drive signal SG.

As described above, the list printing LUT 320 for generating the list image D3 from the original list image D2 based on the input image D1 is generated based on the chromaticity designation range A1 received from the user. Therefore, the list color conversion table 320 is generated based on the designated range A1 according to the user's request, and the list image D3 for adjusting the LUT 310 is printed. Since the list image D3 is dynamically formed according to the designated range A1, it is not necessary to prepare the list printing LUT 320 according to the chromaticity range of the list image D3. Therefore, this specific example can reduce the memory size for storing the list printing LUT. Further, since the chromaticity designation range A1 for printing the list image D3 can be changed, the color of the test image D3a is not limited to the maximum number N2 ² of the test images D3a that can be assigned to the list printing LUT 320. The degree can be changed finely. Therefore, in this specific example, the chromaticity of the output image D5 can be finely adjusted.

(4) Modification:
Various modifications can be considered for the present invention.
For example, the input color system of the LUT may be a CMY color system, an L ^* a ^* b ^* color system, a four-dimensional CMYK color system, or the like in addition to the RGB color system. In addition to CMYKLk, the color materials defined for the output coordinate values are Lc (light cyan), Lm (light magenta), LLk (light light black), Dy (dark yellow), Or (orange), Gr (green), B (Blue), V (violet), an uncolored coloring material for improving image quality, and the like may be included. Here, Lc is cyan having a lower density than C, Lm is magenta having a lower density than M, LLk is an achromatic color having a lower density than Lk, and Dy is yellow having a higher density than Y. is there. When using Lc and Lm, the coefficient used to generate the production printing LUT may be a coefficient that multiplies the output coordinate values of Lc, Lm, and Y in the original LUT. Further, the present technology also includes a case in which some of the color materials of CMYKLk are not present.

The list printing LUT may be a one-dimensional LUT divided according to chromaticity, in addition to the three-dimensional LUT.
In the list printing LUT, the lightness component constituting the input color system may correspond to the input coordinate value of G or B in addition to the input coordinate value of R. Of course, unless it overlaps with other components, the a ^* component may correspond to the input coordinate value of R or B, and the b ^* component may correspond to the input coordinate value of R or G.
The input image for color conversion may be a color image as well as a gray image.
This technique includes a technique for performing the monochrome image print control process of S106 to S124 without performing the determination process of S102 of FIG.
Further, the present technology includes a technology for displaying a list image after color conversion (an image forming apparatus, an image forming method, etc.) in addition to a technology for performing control for printing a list image.

The processing described above may be performed by a printing apparatus. FIG. 14 shows an example of print control processing performed by the printing apparatus 1. This process is performed mainly by the controller 10 of the printing apparatus 1 according to the program PRG2. The print control process may be realized by an electric circuit or a program.
For example, when an image recorded on the memory card 90 is selected and operated on the operation panel 73, the printing apparatus 1 stores the selected image in the RAM 20 and starts a print control process. The printing apparatus 1 may start the print control process when receiving an image and a print instruction from the host apparatus 100 and storing them in the RAM 20.

  When the printing control process is started, the controller 10 branches the process according to the printing method (S202). For example, when performing color printing of an image, such as when color printing is set on the operation panel 73, the printing apparatus 1 performs color conversion on the input image with reference to a color printing LUT (not shown), and prints the converted image. Control. When monochrome printing is performed, such as when monochrome printing is set on the operation panel 73, processing is divided depending on whether the image is a color image or a monochrome image. When monochrome printing a color image, the controller 10 converts the color image into a gray image (S204), and advances the process to S206.

  In S206, the original list image D2 is generated based on the gray input image D1 as shown in FIG. In S208, the original list image D2 is color-converted with reference to the list printing LUT 320 as shown in FIG. In S210, the converted list image D3 is converted into halftone data by the halftone processing unit 43, the halftone data is rearranged by the rasterizing processing unit 44, and a drive signal SG corresponding to the generated raster data is transmitted as a drive signal. Generated by the unit 45 and output to the drive circuit 62. In this way, control for printing the list image D3 is performed. The mechanism unit 50 prints a list image D3 as shown in FIG.

  In S212, a print color selection screen 830 as shown in the upper part of FIG. The print color selection screen 830 shown in FIG. 15 includes a test image D3a selection area 833, a real print execution area 834, a color adjustment range change area 835, a cancel area 836, and the like when the output image D5 is actually printed. ing. The image selection area 833 receives an operation input for selecting the identification number (see FIG. 5) of the test image D3a of the printed material 400 by the input unit 75. Accepting an input in the image selection area 833 corresponds to accepting an input for determining an adjustment amount (coefficient) of the chromaticity of the output image D5.

  The controller 10 branches the process according to the operation to the areas 834 to 836 by the input unit 75 (S214). When the controller 10 accepts an operation to the production print execution area 834, the controller 10 advances the process to S220 and starts the production print control process. Further, when the controller 10 receives an operation on the color adjustment range change area 835, the controller 10 displays a color adjustment list range change screen 840 as shown in the lower part of FIG. 15 on the output unit 74 (S216). The color adjustment list range change screen 840 shown in FIG. 15 includes a selection area 843 of the center image D3d when the list image D3 is printed, a selection area 844 of the range from the center image D3d when the list image D3 is printed, and a list. A print execution area 845, a cancel area 846, and the like are provided. The center image selection area 843 accepts an operation input for selecting the identification number of the test image D3a of the printed matter 400 by the input unit 75. The received identification number corresponds to central chromaticity information representing the central chromaticity (at, bt) of the designated range A1. The range selection area 844 accepts an operation input for selecting the chromaticity range to be changed from the new center image D3d by the input unit 75. The accepted range W corresponds to range information representing a range from the central chromaticity (at, bt) represented by the central chromaticity information.

  When the controller 10 accepts an operation on the list print execution area 845, the controller 10 accepts in the range selection area 844 from the center chromaticity (at, bt) corresponding to the test image D3a of the identification number accepted in the center image selection area 843. A list printing LUT 320 is generated based on the range W (S218). Thereafter, the controller 10 performs color conversion on the original list image D2 with reference to the newly generated list printing LUT 320 (S208), and performs halftone processing and rasterization processing on the converted list image D3 to obtain raster data. Is output to the drive circuit 62 (S210). As a result, a list image D3 in which the chromaticity is changed in the range W received in the range selection area 844 from the central chromaticity represented by the test image D3a having the identification number received in the center image selection area 843 is printed.

  When the production print execution area 834 is operated on the print color selection screen 830 displayed in S212, the processes of S220 to S224 are performed. First, the controller 10 based on the adjustment amount (coefficients Act ′, Amt ′, Ayt ′) of the chromaticity (at ′, bt ′) of the test image D3a corresponding to the identification number selected in the image selection area 833. The LUT 300 is adjusted to generate a production printing LUT 310 (S220). In S <b> 222, the color conversion unit 42 performs color conversion on the RGB color system input image D <b> 1 with reference to the production printing LUT 310. In S224, the color-converted image is converted into halftone data by the halftone processing unit 43, the halftone data is rearranged by the rasterization processing unit 44, and the drive signal SG corresponding to the generated raster data is sent to the drive circuit 62. Output. The mechanism unit 50 forms an output image D5 on the substrate 410 as shown in FIG. 1 according to the drive signal SG.

  Also in this modification, a list printing LUT 320 is generated based on the chromaticity designation range A1 received from the user, and a list image D3 for adjusting the LUT 310 is printed. For this reason, it is not necessary to prepare the list printing LUT 320 according to the chromaticity range of the list image D3. Therefore, this modification can also reduce the memory size for storing the list printing LUT.

(5) Conclusion:
As described above, according to the present invention, it is possible to provide a technique or the like that can reduce the memory size for storing the list color conversion table according to various aspects. Needless to say, the above-described basic actions and effects can be obtained even with a technique that does not have the constituent requirements according to the dependent claims but includes only the constituent requirements according to the independent claims.
In addition, the configurations disclosed in the embodiments and modifications described above are mutually replaced, the combinations are changed, the known technology, and the configurations disclosed in the embodiments and modifications described above are mutually connected. It is possible to implement a configuration in which replacement or combination is changed. The present invention includes these configurations and the like.

DESCRIPTION OF SYMBOLS 1 ... Printing apparatus, 10 ... Controller, 50 ... Mechanism part, 61 ... Head, 66 ... Ink (color material), 73 ... Operation panel, 74 ... Output part, 75 ... Input part, 100 ... Host apparatus, 174 ... Display apparatus , 300 ... Original LUT (original color conversion table), 310 ... LUT (color conversion table), 320 ... LUT for list printing (list color conversion table), 321 ... Lightness component, 322 ... Chromaticity component, 380 ... Coefficient table , 400 ... printed matter, 410 ... substrate, A0, A1, A11 to A13 ... range, D1 ... input image, D2 ... original list image, D3, D31 to D35 ... list image, D5 ... output image, D2a, D3a ... image , D3d ... center image, R1 to R5 ... area, U0 ... print control device, U1 ... chromaticity range acceptance unit, U2 ... list color conversion table generation unit, U3 ... list print control unit, U4 ... list Image forming unit, U5 ... color conversion table adjusting unit.

Claims (10)

A print control device that performs control to convert an input image with reference to a color conversion table that defines a correspondence relationship between an input coordinate value and a usage amount of a color material for printing, and to print the output image after conversion,
A chromaticity range accepting unit for accepting a designated range of chromaticity when printing a list image for adjusting the color conversion table;
A list color conversion table generating unit for generating a list color conversion table for generating a list image whose chromaticity is changed to the specified range from an original list image based on the input image; and
A print control apparatus comprising: a list print control unit that performs control for converting the original list image with reference to the generated list color conversion table and printing the obtained list image. The chromaticity range reception unit receives input of central chromaticity information representing the chromaticity of the center of the specified range, and range information representing a range from the central chromaticity represented by the central chromaticity information,
The list color conversion table generation unit generates the list color conversion table based on a range represented by the range information from a central chromaticity represented by the center chromaticity information. Print control device. The list color conversion table generating unit generates the list color conversion table for generating the list image including test images having different chromaticities determined by the specified range from the original list image based on the specified range. Generated,
The list print control unit performs control to convert the original list image with reference to the list color conversion table and print a list image including the number of the test images determined by the specified range. The printing control apparatus according to claim 2.   4. The print control according to claim 3, wherein the number of the test images included in the list image and the specified range are in a relationship in which the specified range becomes wider as the number of the test images included in the list image increases. apparatus.   The number of grid points along the coordinate axis of the input color system in the color conversion table for list is smaller than the number of grid points along the coordinate axis of the input color system in the color conversion table. 5. The printing control apparatus according to claim 1.   The number of gradations of the color material usage amount in the list color conversion table is smaller than the number of gradations of the color material usage amount in the color conversion table. Print control device. The plurality of components constituting the input color system in the list color conversion table include a lightness component corresponding to lightness and a chromaticity component corresponding to chromaticity to be adjusted,
The correspondence relationship between the lightness component and the color material usage amount in the list color conversion table is generated based on the correspondence relationship of the color conversion table. The printing control apparatus described.   Based on the adjustment amount corresponding to the input, an input for determining the adjustment amount of the chromaticity of the output image is received, and the original color conversion table that defines the correspondence relationship between the input coordinate value and the usage amount of the color material for printing is used. The print control apparatus according to claim 1, further comprising: a color conversion table adjustment unit that adjusts and generates the color conversion table. The input coordinate value defined in the color conversion table is a value corresponding to lightness,
The printing control apparatus according to any one of claims 1 to 8, wherein a color material whose usage is defined in the color conversion table and the list color conversion table includes a chromatic color material. A print control method for performing control to convert an input image with reference to a color conversion table that defines a correspondence relationship between an input coordinate value and a usage amount of a color material for printing, and to print the output image after conversion,
A chromaticity range receiving step of receiving a specified range of chromaticity when printing a list image for adjusting the color conversion table;
A list color conversion table generating step for generating, based on the specified range, a list color conversion table for generating a list image whose chromaticity has been changed to the specified range from an original list image based on the input image;
A list printing control step of performing control to convert the original list image with reference to the generated list color conversion table and to print the obtained list image.

Images