JP5438944B2 - Density calculation device, concentration setting device, concentration calculation program, and concentration setting program - Google Patents

Description

  The present invention relates to a density calculation device, a density calculation program for calculating a printing density of a color material when printing an image in a printing system, a density setting device for setting a printing density of a color material, and a density setting program.

  Conventionally, in the field of printing, an image is edited using a personal computer, a film original is created based on the edited image, a printing plate is created based on the film original, and the printing plate is mounted on a printing press. Ink is then applied, and a printed image is generated through a series of processes in which the applied ink is transferred onto printing paper. In recent years, CTP (Computer To Plate) for printing an image directly on a printing plate has been incorporated into the printing press, and a digital printing press has been developed in which a plate making process and the like that require skilled techniques have been automated. Demand is growing as a printing machine for small lots and many types of products that produce many kinds of printed materials.

  By the way, a series of operations for printing on paper is a large-scale operation in which the number of printing units is several hundred copies, and processing time and cost are increased. Therefore, it is easier than a printing press before performing an actual printing operation. A proof image in which a print image is reproduced by a simple printer or the like is created, and the proof image is used to check the finished print image in advance. Furthermore, in recent years, proof images have also been displayed on calibrated monitors, making it possible to more efficiently check the image of the printed image in each printing step, eliminating waste of paper more efficiently. Is becoming possible.

  However, in advance confirmation using a proof image, the image and overall image of the print image can be grasped, but the color and finish of the print image including the thickness of the ink are printed on the printing machine. Has been confirmed by. Actually, the preferred ink thickness varies depending on the printing media such as newspapers, advertisements, posters, magazines, etc., so when printing images are created, the desired color can be obtained by driving the printing press and repeatedly performing test printing. Until the above is obtained, the user manually adjusts the printing density of the ink in the printing press, and there is a problem that a large amount of paper is lost. In addition, the amount of waste paper generated until the final ink print density is determined is almost constant regardless of the number of printed copies, so the smaller the number of printed copies, the greater the proportion of lost paper. Become. For this reason, in a digital printer for a small lot and a wide variety, it is important to reduce the cost by increasing the time until the ink printing density is determined and suppressing the occurrence of waste paper.

In this regard, Patent Document 1 generates a predicted image in which a print image is predicted based on the opening value of the ink key for adjusting the print density of the ink and the pixel value of the image data, and the user selects the predicted image. A technique for manually adjusting the print density of ink with reference is described, and Patent Document 2 obtains a color coordinate value using an ICC profile for a halftone dot area ratio at a point of interest in a printed image. A technique is described in which the color coordinate value is set as a target density value, and the print density of the ink is automatically adjusted so that the density value of a point of interest in the printed image approaches the target density value. In the technique described in Patent Document 1, since it is possible to roughly check the color of a printed image before printing, it is possible to reduce the processing time until the printing density of ink is determined. In this technique, the print density of the ink can be easily adjusted so that the color of the printed matter on the reference printer can be reproduced on another printer.
JP 2001-347645 A JP 2004-106523 A

  However, in the technique described in Patent Document 1, in order to improve the prediction accuracy of a print image, it is necessary to finely associate the opening value of the ink key and the pixel value of the image data. End up. In addition, although the predicted image of the printed image can be confirmed, the work of determining the print density of the ink necessary for correcting the color of the predicted image to a desired color requires skillful technology and experience. There is also a problem that it is difficult for few users to adjust the printing density of ink.

  In the technique described in Patent Document 2, since the print density of the ink of the printed image is finely adjusted while actually performing the trial printing until the target density value is realized, the initial state is set appropriately. If this is not done, it takes time until the printing density of the ink is stabilized, which eventually causes a large amount of paper loss.

  In view of the above circumstances, the present invention is a density calculation device, a density setting device, a density calculation program, which can easily adjust the printing density of a color material without suppressing generation of waste paper and without requiring a skilled technique. And it aims at providing a concentration setting program.

The density calculation apparatus of the present invention that achieves the above object is printed by a printing system that sets the print density of each of a plurality of color materials and uses the color material at the print density to print an image based on the image data. An image data acquisition unit for acquiring print image data representing a print image;
A location designation unit for designating a location on the print image represented by the print image data acquired by the image data acquisition unit;
A target color acquisition unit for acquiring a target color for the color of the above-mentioned location;
The printing system prints the chart image based on the chart image data representing the chart image in which the patches of multiple colors are arranged at each print density while changing the print density to a series of print densities for each color of the multiple colors. Based on the correspondence between the color of each patch and the print density obtained as a result, and the temporary print density designated for each of the color materials of a plurality of colors, based on the print image data and the temporary print density A color estimation unit that estimates a printing color at the location by the printing system;
Density calculation for calculating the print density of each of the color materials of a plurality of colors using the color estimation unit so that the target color acquired by the target color acquisition unit is realized at the above-described location by the printing system based on the print image data And a section.

  Here, the “location” in the present invention may be one point, a region, or a point group composed of a plurality of points.

  The color material print density referred to in the present invention indicates the density of a print image set by adjusting the supply amount of the color material by opening / closing the ink key or the like.

  The applicant of the present invention determines the print color of a print image when the print density of the color material is generated based on print image data in which the halftone value of each of the plurality of colors is 100%. The standard print density that becomes the standard color and the change print in which the print density is changed from the standard print density to the optical density ± 0.1, ± 0.2, etc. for each color material of multiple colors Print a chart image in which patches of multiple colors are arranged with each density set, and predict the print color at the desired print density using the colorimetric results of the patches on each generated chart image A printing color prediction method is proposed. According to this print color prediction method, the color of the print image can be accurately confirmed before the image is actually printed.

  According to the density calculation apparatus of the present invention, the print density of each of the color materials of a plurality of colors such that the target color is realized at a specified location on the print image printed by the printing system by the reverse calculation of the print color prediction method described above. Is calculated. For this reason, it is possible to easily set the print density without requiring skilled techniques, to shorten the time required to determine the print density of the color material, and to suppress the occurrence of paper loss be able to.

Further, in the concentration calculation apparatus of the present invention, the location designating unit designates a plurality of locations with different priorities as the locations,
The target color acquisition unit acquires each target color for each of a plurality of locations.
The density calculation unit has a common print density at which the target colors of each of the plurality of locations are realized by the printing system, and has a relatively low priority for realizing the accuracy of the plurality of locations where the priority is relatively high. It is preferable that the calculation is performed with more emphasis on the realization accuracy at the location.

  Usually, in a printing system, colors are often expressed by a combination of C, M, Y, and K color materials, and a target color at each of a plurality of locations can be obtained only by combining the print densities of these four color materials. It is difficult to realize these simultaneously. According to the preferable concentration calculation device, since the realization accuracy at a location having a relatively high priority among the plurality of locations is calculated with more importance than the realization accuracy at a location having a relatively low priority, for example, a company Important colors such as logo colors can be realized with high accuracy.

  In the density calculation apparatus of the present invention, the location specifying unit displays a print image based on the print image data, and specifies the location according to a selection operation for selecting a location on the displayed print image. Is preferred.

  The user can easily specify a location where the target color is realized simply by selecting an important color on the displayed print image.

Further, in the density calculation apparatus of the present invention, the location specifying unit specifies an area on the print image,
It is preferable that the target color acquisition unit acquires a target color for the average color in the region.

  Colors such as skin color, green color, sky blue color, and gray color are important factors that determine the impression of printed matter, and are treated as important colors in the field of printing. According to the density calculation apparatus of the present invention, it is possible to easily obtain a visually preferable print image by roughly specifying a region having an important color such as green or skin color on the print image.

Further, in the density calculation apparatus of the present invention, the location specifying unit specifies an area on the print image,
Preferably, the target color acquisition unit acquires a target color for a color that appears most frequently in the region.

  According to this preferred density calculation device, even if important colors are dispersed on the printed image, it is only necessary to specify an area containing a lot of important colors. An actual printed image can be obtained.

In the density calculation apparatus of the present invention, the print image data is a set of color data representing the color of each point on the print image,
It is preferable that the location designation unit designates, as a location, one or more point sets selected from the point set having a larger number of points among the point set composed of the points on the print image having the same color data. .

  According to this preferable density calculation device, it is possible to save the user from selecting an important color and generate a print image in which an important color having a high appearance frequency is expressed by a target color.

In the density calculation apparatus of the present invention, the print image data is a set of color data representing the color of each point on the print image,
It is preferable that the location designating unit designates each point on the print image in which the color is represented by the same color data as the color data representing a predetermined important color as the location.

  By storing a company logo color or the like as an important color in advance, it is possible to easily obtain a printed image in which the important color is expressed by a target color.

  In the concentration calculation apparatus of the present invention, it is preferable that the location designation unit assigns a higher priority to each of a plurality of locations in descending order of the area of the location.

  The important colors on the printed image often occupy a large area, and according to this preferable density calculation device, it is possible to easily generate a printed matter in which the important colors are expressed by the target color.

  In the density calculation apparatus of the present invention, the target color acquisition unit acquires the color of the above-described portion on the print image when the print image is printed by a printing system different from the printing system as the target color. Is preferred.

  According to this preferable density calculation apparatus, it is possible to easily obtain a print image color-matched to a color sample generated by another printing system.

  Further, in the density calculation apparatus of the present invention, the target color acquisition unit calculates the color of the location based on the correspondence between the print data and the color on the print image when the print image is printed by another printing system. It is preferable that the target color is calculated and acquired.

  In the field of printing, a print standard color profile that indicates a correspondence relationship between print data and the color of a print image generated based on the print data by a reference printer is widely used. In this preferable density calculation apparatus, the print color in the reference printer can be reproduced by acquiring the target color using the print standard color profile.

  Further, in the density calculation apparatus of the present invention, the target color acquisition unit obtains a colorimetric value obtained by measuring the color of the location on a printed material obtained by printing a print image with another printing system as a target color. It is also preferable that it is acquired as

  For example, by obtaining a colorimetric value of a location designated on a printed material generated by the above-described reference printing machine as a target color, it is possible to accurately realize the same color as the color of the designated location on the printed material. it can.

  Further, in the density calculation apparatus of the present invention, an expected image of a print image obtained by printing by the printing system is displayed based on the print density and print image data of each of the color materials calculated by the density calculation unit. It is preferable that a display unit is provided.

  By displaying the predicted image, it is possible to confirm the quantitative accuracy of the print density and the finished print image without actually performing printing.

In the concentration calculation apparatus of the present invention,
Each patch obtained by printing the chart image with the print density of the printing system set to the standard print density when the print color of the image printed based on the predetermined image data becomes the predetermined standard color The reference color and the reference for the color of each patch obtained by printing the chart image with the print density of the printing system set to a series of print densities that change from the standard print density for each of a plurality of color materials A storage unit for storing the color difference for the color and the correspondence between the density difference of the print density and the standard print density,
The color estimation unit receives the provisional print density of each of the color materials of a plurality of colors and the designation of the above part, obtains a related part corresponding to the part among the correspondences stored in the storage part, and determines the reference of each patch It is preferable that the printing color at a location is estimated by an interpolation process using the color and the related portion.

  For example, when the print density of each color material of C, M, Y, and K is changed by 13 steps, 28561 print densities are created by combining them, and the print color is predicted in all of them. When trying to save the correspondence, a huge amount of memory is required. According to this preferred density calculation device, the reference color of each patch and the correspondence between the color difference of the patch color with respect to the reference color and the density difference of the print density with respect to the standard print density are stored, and depending on the designated location Only the related portion is acquired, and the print color of the designated place in the state where the temporary print density is set is estimated. For this reason, it is possible to estimate the print color while suppressing increases in memory capacity and processing time.

In the concentration calculation apparatus of the present invention,
The density calculation unit calculates a determinant Ax = y (where A is a matrix, x is a vector representing a density difference, and y is a vector representing a print color difference) corresponding to the correspondence stored in the storage unit. A general inverse matrix A ′ for the matrix A that uniquely gives a solution x ′ satisfying the norm minimum and least squares solution to the exact solution solved for x by the determinant x ′ = A′y, and the determinant x ′ = Substitute the difference between the color of the above location and the target color into y of A'y to obtain a solution of the density difference, and use the density shifted from the standard density by the obtained density difference as the starting point of the temporary print density. Application form in which the target color is searched for the print density that is realized as the print color at the above location by repeatedly specifying the provisional print density for the estimation unit and obtaining the print color estimated by the color estimation unit Is preferred.

For example, when printing an image using four color materials of C, M, Y, and K, x is four-dimensional, and the color of the image is measured by a colorimeter and the measured values L *, a *, and b are measured. When * is obtained, since y is three-dimensional, there is no inverse matrix A ⁻ for matrix A, but by giving a condition that the norm minimum and least squares solutions are satisfied, a solution x ′ approximated to an exact solution The general inverse matrix A ′ for uniquely determining can be determined. According to this preferred density calculation device, the print density close to the print density that realizes the target color is calculated by the general inverse matrix, and the print density that actually realizes the target color is searched from the calculated print density as a starting point. Therefore, it is possible to reduce the problem of being addicted to the local solution and to calculate the print density at high speed.

In the concentration calculation apparatus of the present invention,
When the target color acquisition unit acquires a plurality of target colors for each of a plurality of locations, the density calculation unit calculates the color of each location and the target color for that location in y of the determinant x ′ = A′y. By substituting the difference, a simultaneous equation is created, and by solving the simultaneous equation, a solution for the density difference common to multiple target colors is obtained, and the density shifted from the standard density by the obtained density difference As a starting point, it is more preferable to search for a print density at which a plurality of target colors are realized as print colors at a plurality of locations.

  Multiple target colors are set by creating simultaneous equations that show the correspondences between multiple target colors and calculating the print density common to multiple target colors using a general inverse matrix that satisfies the simultaneous equations. Even in this case, it is possible to efficiently calculate the print density that realizes these target colors.

The density setting device of the present invention that achieves the above object is a printing system that prints an image based on image data by setting the print density of each of the color materials of a plurality of colors and using the color material at the print density. An image data acquisition unit for acquiring print image data representing a print image to be printed;
A location designation unit for designating a location on the print image represented by the print image data acquired by the image data acquisition unit;
A target color acquisition unit for acquiring a target color for the color of the above-mentioned location;
The printing system prints the chart image based on the chart image data representing the chart image in which the patches of multiple colors are arranged at each print density while changing the print density to a series of print densities for each color of the multiple colors. Based on the correspondence between the color of each patch and the print density obtained as a result, and the temporary print density designated for each of the color materials of a plurality of colors, based on the print image data and the temporary print density A color estimation unit that estimates a printing color at a location by the printing system;
A density for calculating the print density of each of a plurality of color materials using a color estimation unit so that the target color acquired by the target color acquisition unit is realized at the location by the printing system based on print image data. A calculation unit;
And a density setting unit that sets, in a printing system, the printing density of each of the color materials calculated by the density calculation unit.

  According to the density setting device of the present invention, it is possible to suppress the occurrence of waste paper and easily adjust the printing density of the color material without requiring skilled techniques.

  Note that the density setting device is only shown here for its basic form, but this is merely to avoid duplication, and the density setting apparatus according to the present invention is not limited to the above basic form, Various forms corresponding to each form of the above-described concentration calculation apparatus are included.

Further, the concentration calculation program of the present invention that achieves the above object is executed in a computer, and on the computer,
Image data for acquiring print image data representing a print image printed by a printing system that prints an image based on image data by setting the print density of each color material of a plurality of colors and using the color material at the print density An acquisition unit;
A location designation unit for designating a location on the print image represented by the print image data acquired by the image data acquisition unit;
A target color acquisition unit for acquiring a target color for the color of the location;
The printing system prints the chart image based on the chart image data representing the chart image in which the patches of multiple colors are arranged at each print density while changing the print density to a series of print densities for each color of the multiple colors. Based on the correspondence between the color of each patch and the print density obtained as a result, and the temporary print density designated for each of the color materials of a plurality of colors, based on the print image data and the temporary print density A color estimation unit that estimates a printing color at a location by the printing system;
Density calculation for calculating the print density of each of the color materials of a plurality of colors using the color estimation unit so that the target color acquired by the target color acquisition unit is realized at the above-described location by the printing system based on the print image data It is characterized by building a part.

  Note that the concentration calculation program also shows only those basic forms here, but this is merely to avoid duplication, and the concentration calculation program according to the present invention is not limited to the above basic form. Various forms corresponding to each form of the above-described concentration calculation apparatus are included.

  Further, the element such as an image data acquisition unit constructed on the computer system by the density calculation program of the present invention may be one element constructed by one program part, and a plurality of elements are one program. It may be constructed by parts. In addition, these elements may be constructed so as to execute such actions by themselves, or constructed by giving instructions to other programs and program components incorporated in the computer system. May be.

In addition, the concentration setting program of the present invention that achieves the above object is executed in a computer, and on the computer,
Image data for acquiring print image data representing a print image printed by a printing system that prints an image based on image data by setting the print density of each color material of a plurality of colors and using the color material at the print density An acquisition unit;
A location designation unit for designating a location on the print image represented by the print image data acquired by the image data acquisition unit;
A target color acquisition unit for acquiring a target color for the color of the above-mentioned location;
The printing system prints the chart image based on the chart image data representing the chart image in which the patches of multiple colors are arranged at each print density while changing the print density to a series of print densities for each color of the multiple colors. Based on the correspondence between the color of each patch and the print density obtained as a result, and the temporary print density designated for each of the color materials of a plurality of colors, based on the print image data and the temporary print density A color estimation unit for estimating a printing color at the location by the printing system;
Density calculation for calculating the print density of each of the color materials of a plurality of colors using the color estimation unit so that the target color acquired by the target color acquisition unit is realized at the above-described location by the printing system based on the print image data And
And a density setting unit configured to set a printing density of each of the color materials calculated by the density calculation unit in the printing system.

  The density setting program is only shown here for its basic form, but this is merely to avoid duplication, and the density setting program according to the present invention is not limited to the above basic form. Various forms corresponding to each form of the above-described concentration calculation apparatus are included.

  Furthermore, the elements such as the image data acquisition unit constructed on the computer system by the density setting program of the present invention may be constructed by one program part, and a plurality of elements may be constructed by one program. It may be constructed by parts. In addition, these elements may be constructed so as to execute such actions by themselves, or constructed by giving instructions to other programs and program components incorporated in the computer system. May be.

  According to the present invention, it is possible to easily adjust the printing density of a color material without generating a waste paper and without requiring a skilled technique.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a printing system in which an embodiment of the present invention is incorporated.

  A printing system 1 shown in FIG. 1 mainly generates a printing image 20 representing a printing image by editing a printing machine 20 that creates a printing image using inks of C, M, Y, and K colors. The system includes a workstation 30, a control device 10 that controls the printing density of each of the C, M, Y, and K inks in the printing machine 20, and a colorimeter that measures a printed image. In practice, the printing system 1 is connected to a color scanner that reads an original image, a printer that prints out an image based on image data, and the like.

The workstation 30 includes R, G, and B color separation image data obtained by reading a document with a color scanner (not shown), and C, M, Y, and K four colors created using a personal computer or the like. Separation image data, color separation image data of L ^* , a ^* , and b ^* three colors obtained by photographing a subject with a digital camera are input. In the workstation 30, electronic plate collection based on the input color separation image data is performed by an operator, and print image data representing a page of an image for printing is generated. The printing machine 20 expresses an image with a set of pixels, and the print image data represents an image with a set of pixels having any half-% value from 0% to 100%. , M, Y, K color plate halftone data is used. The generated print image data is sent to the printing machine 20.

  The printing press 20 has a CTP (not shown) that generates printing plates for C, M, Y, and K colors, and a printing plate for printing and is coated with ink so that C, Image forming units 21Y, 21M, 21C, and 21K that form color plate images of M, Y, and K colors are provided, and printing formed on a sheet on the downstream side of the image forming units 21Y, 21M, 21C, and 21K. A colorimeter 11 for measuring an image is provided. When the printing image data is transmitted to the printing machine 20, printing plates for C, M, Y, and K colors are generated based on the printing image data, and printing plates for these C, M, Y, and K colors are generated. Mounted on the image forming units 21Y, 21M, 21C, and 21K. In the image forming units 21Y, 21M, 21C, and 21K, the ink having the printing density controlled by the control device 10 is applied to the printing plate, and the ink is sequentially transferred onto the paper so C, M, Y, and K color plate images are formed and sequentially overlaid to generate a print image.

  Here, since the degree of light reflection on the surface of the paper varies depending on the type of printing media such as newspapers, advertisements, magazines, etc., even if the same amount of ink of the same color is supplied, the color impression of the finished printed image Will change. However, it is necessary to always express the logo color of a company stably in the same color, and the workstation 30 uses C, M, Y, and K colors in the printing machine 20 for important colors on a printed image. The initial print density of the ink is calculated. The calculated initial print density is transmitted to the control device 10, and the control device 10 adjusts the opening / closing states of the ink fountains of the image generating units 21Y, 21M, 21C, and 21K, so that the print density of each color ink is the initial print density. Set to

  When the initial print density of ink is set, the image generators 21Y, 21M, 21C, and 21K perform trial printing, and the color of the printed image generated by the trial printing is measured by the colorimeter 11, and the control device 10 The test printing is repeated while finely adjusting the printing density of the ink. When the colorimetric value transmitted from the colorimeter 11 reaches the target color and the printing density of the ink is stabilized, the start of printing is transmitted from the workstation 30 to the control device 10, and actual printing is performed instead of the trial printing. . In this embodiment, by setting a value close to the target print density for realizing the target color as the initial print density of the ink, the time until the print density of the ink is stabilized is increased, and the waste paper Occurrence is suppressed.

  Here, in the following, details of processing executed in the workstation 30 will be described.

  As shown in FIG. 1, the workstation 30 is a large-sized personal computer. As shown in FIG. 1, the work station 30 has a main body device 31 and an image display device 32 that displays an image on a display screen 32a in accordance with an instruction from the main body device 31. By specifying an arbitrary position on the display screen 32a by inputting a keyboard 33 for inputting various types of information according to key operations to the main unit 31, an instruction corresponding to an icon or the like displayed at that position is input. A mouse 34 is provided.

  FIG. 2 is a hardware configuration diagram of the workstation.

  Inside the main unit 31 of the workstation 30, as shown in FIG. 2, a main memory that is loaded with a CPU 301 for executing various programs and a program stored in the hard disk device 303 is read and executed for execution by the CPU 301. 302, the hard disk device 303 in which various programs and data are stored, the FD 41 are loaded, the FD drive 304 that accesses the FD 41, the CD-ROM drive 305 that accesses the CD-ROM 42, and the image data from the management server 20 The I / O interface 306 for sending various instruction data to the management server 20 is built in, and these various elements, and the image display device 32, keyboard 33, and mouse 34 shown in FIG. Are connected to each other.

  Here, the CD-ROM 42 stores a print density adjustment program 100 (see FIG. 3) which is an embodiment of each of the density calculation program and the density setting program of the present invention.

  FIG. 3 is a conceptual diagram showing the CD-ROM 42.

  As illustrated in FIG. 3, the print density adjustment program 100 stored in the CD-ROM 42 includes an image acquisition unit 110, a target color setting unit 120, a target color acquisition unit 130, a color prediction unit 140, a density adjustment unit 150, and an operation unit. 160 and an image display unit 170.

  The CD-ROM 42 is loaded in the CD-ROM drive 305 of the workstation 30, and the print density adjustment program 100 stored in the CD-ROM 42 is uploaded to the workstation 30 and stored in the hard disk device 303. When the print density adjustment program 100 is activated and executed, the print density adjustment apparatus 200 (see FIG. 4), which is an embodiment of the density calculation apparatus and density setting apparatus of the present invention, is provided in the workstation 30. Is built.

  In the above description, the CD-ROM 42 is exemplified as a storage medium for storing the print density adjustment program 100. However, the storage medium for storing the print density adjustment program 100 is not limited to the CD-ROM. It may be a storage medium such as an optical disk, MO, FD, or magnetic tape. Further, the print density adjustment program 100 may be directly supplied to the workstation 30 via the I / O interface 306 without using a storage medium.

  Details of each part of the print density adjustment program 100 will be described together with the operation of each part of the print density adjustment apparatus 200.

  FIG. 4 is a functional block diagram of the print density adjusting apparatus 200.

  The print density adjustment apparatus 200 includes an image acquisition unit 210, a target color setting unit 220, a target color acquisition unit 230, a color prediction unit 240, a density adjustment unit 250, an operation unit 260, an image display unit 270, And a storage unit 280.

  The image acquisition unit 210, the target color setting unit 220, the target color acquisition unit 230, the color prediction unit 240, the density adjustment unit 250, the operation unit 260, and the image display unit 270 constituting the print density adjustment apparatus 200. Are the image acquisition unit 110, the target color setting unit 120, the target color acquisition unit 130, the color prediction unit 140, the density adjustment unit 150, the operation unit 160, and the image display unit 170 that constitute the print density adjustment program 100 of FIG. Correspond to each.

  4 is composed of a combination of computer hardware and an OS or application program executed on the computer, whereas each element of the print density adjustment program 100 shown in FIG. The difference is that it is configured only by the application program.

  FIG. 5 is a flowchart showing a flow of a series of processes until the print density of ink is set in the print density adjusting apparatus 200 shown in FIG.

  Hereinafter, the operation of each element of the print density adjustment apparatus 200 shown in FIG. 4 will be described according to the flowchart of FIG. 5, and the elements of the print density adjustment program 100 shown in FIG.

  Print image data edited by the operator using a personal computer or the like is acquired by the image acquisition unit 210 in FIG. 4 (step S1 in FIG. 5). As described above, in the present embodiment, as the print image data, halftone C, M, Y, and K color plates representing an image with a set of pixels having any halftone value from 0% to 100%. % Data is acquired. The image acquisition unit 210 corresponds to an example of the image data acquisition unit referred to in the present invention. The acquired print image data is transmitted to the target color setting unit 220 and the image display unit 270.

  The image display unit 270 displays an attention color setting screen for setting an important attention color among the colors of the pixels in the print image represented by the print image data (that is, the location in the print image) as shown in FIG. Display above.

  FIG. 6 is a diagram illustrating an example of an attention color setting screen.

  The attention color setting screen 500 shown in FIG. 6 includes a print image 510 represented by the print image data, a color information display unit 520 indicating information on the attention color set using the attention color setting screen 500, and the printing machine 20. A density manual adjustment unit 530 for manually adjusting the print density of ink, an add button 541 for adding a target color, a delete button 542 for deleting a target color, and calculation of an initial print density of ink An automatic adjustment button 543 for starting and an execution button 544 for setting the print density of ink for the printing press 20 are provided.

  When the user selects the add button 541 using the mouse 34 or the like, a designation method selection screen for selecting the designation method of the target color is displayed on the display screen 32a of FIG.

  FIG. 7 is a diagram illustrating an example of the designation method selection screen.

  On the designation method selection screen 600, various radio buttons for manually designating a target color, various radio buttons for automatically designating a target color, and a next button for displaying information on the specified target color 621 and a cancel button 622 for canceling the setting. As radio buttons for manually specifying a target color, a point selection radio button 611 for specifying the color of the point as a target color by selecting a point on the print image 510 shown in FIG. By selecting an area on the print image 510 shown in FIG. 6, an area radio button 612 for preparing an average value or mode value of colors in the area as a target color is prepared. As a radio button for designating, a frequency analysis radio button 613 that uses a color having a high appearance frequency in the print image 510 as a target color, and an important color stored in advance in the storage unit 280 in FIG. A DB collation radio button 614 to be designated is prepared.

  When the user selects the point selection radio button 611 or the area radio button 612 using the mouse 34 or the like and further selects the next button 621, the attention color setting screen 500 shown in FIG. 6 is displayed again.

  When a point of interest on the print image 510 on the target color setting screen 500 is selected with the point selection radio button 611 selected, position information of the target point is transmitted from the operation unit 260 of FIG. 4 to the target color setting unit 220. It is done. Attention color setting section 220 acquires half percent data representing a notice location indicated by the position information transmitted from operation portion 260 in the print image data, and the color represented by the half percent data is temporarily set as a notice color. .

  In addition, when an area including an important color is selected on the print image 510 of the attention color setting screen 500 with the area radio button 612 selected, the position information of the area is displayed from the operation unit 260 of FIG. This is transmitted to the setting unit 220. The attention color setting unit 220 acquires half-% data in the area indicated by the position information transmitted from the operation unit 260 from the print image data, and temporarily sets the average color represented by the half-% data as the attention color. Is done.

  When the target color is temporarily set, the target color setting unit 220 instructs the image display unit 270 to display the set color information screen for displaying the target color information, and the set color information screen is displayed on the display screen 32a. .

  FIG. 8 is a diagram illustrating an example of the setting color information screen.

  Part (A) of FIG. 8 shows an example of a temporarily set color information screen 630 for displaying information of a target color temporarily set using the target color setting screen 500. In the temporary setting color information screen 630, a color value display unit 631 for displaying the halftone value of each color of CMYK of the temporarily set target color, and a priority setting unit for setting the priority of the target color 632, a reselect button 633 for reselecting the target color by returning to the target color setting screen 500, a cancel button 635 for setting the target color, a target color, and a target color for the target color. A next button 634 is set for setting the.

  The color value display unit 631 displays the halftone value of the target color temporarily set by the target color setting unit 220, but the user can finely adjust the halftone value manually. In this example, the priority set in the priority setting unit 632 has five levels from “1” to “5”, and the higher the numerical value, the higher the priority.

  As described above, the target color is manually set.

  Further, when the user selects a frequency analysis radio button 613 or a DB collation radio button 614 that is a radio button for automatically designating a target color on the designation method selection screen 600 of FIG. 7, and further selects the next button 621. The selected content is transmitted from the operation unit 260 to the target color setting unit 220.

  When the frequency analysis radio button 613 is selected, the target color setting unit 220 analyzes a plurality of halftone data representing each of all pixels on the print image constituting the print image data, and the halftone value is the same. The total number of pixels is calculated. Furthermore, a predetermined number (two in this example) of halftone values having a large calculated total number is selected, and the color represented by the selected halftone value is temporarily set as a target color.

  When the DB collation radio button 614 is selected, the attention color setting unit 220 acquires important color information stored in advance in the storage unit 280 and temporarily sets the important color as the attention color. Important colors include the skin color that determines the impression of printed matter, gray, and the company logo color, corporate color, and product color.

  When the attention color is set, the attention color setting unit 220 instructs the image display unit 270 to display the setting color information screen for displaying the attention color information, and the setting color information screen is displayed on the display screen 32a.

  Part (B) of FIG. 8 shows an example of an automatically set color information screen 640 for displaying information of a color of interest that is temporarily set automatically using the color of interest setting screen 500. On the automatic setting color information screen 640, the halftone value of the set target color is displayed, and the priority setting unit 642 for setting the priority of the target color and the addition as the target color are determined. There are provided a check box 641 for canceling, a cancel button 644 for setting the target color, and a next button 633 for setting a target color for the target color.

  As described above, the target color is automatically set.

  When the user selects the next button 634 or 643 shown in FIG. 8 using the mouse 34 or the like, the setting content on the temporary setting color information screen 630 or the automatic setting color information screen 640 is transferred from the operation unit 260 to the attention color setting unit 220. Reportedly. The attention color setting unit 220 sets the color represented by the final halftone value included in the transmitted setting contents as the attention color. A combination of the operation unit 260 and the target color setting unit 220 corresponds to an example of a location designation unit according to the present invention. Information about the set target color is transmitted to the target color acquisition unit 230.

  When the target color information is transmitted, the target color acquisition unit 230 instructs the image display unit 270 to display a target color selection screen for selecting a target color acquisition method, and the target color selection screen is displayed on the display screen 32a. The

  FIG. 9 is a diagram illustrating an example of the target color selection screen.

  The target color selection screen 650 displays the halftone value of the set target color, radio buttons 651 and 652 for selecting the target color for acquiring the target color, and the target color using the color reference profile. A profile radio button 653 for acquisition, a color sample radio button 654 for measuring a color sample to acquire a target color, an execution button 657 for instructing acquisition of the target color, and target colors of all target colors are acquired An end button 658 for informing the user, a cancel button 659 for instructing to stop acquisition of the target color, and a target color display unit 656 for displaying the acquired target color are provided.

In this example, when a plurality of attention colors are set, the target colors are acquired one by one in order from the attention colors selected by the radio buttons 651 and 652. In addition, the storage unit 280 previously stores print data (half-tone values of each color of C, M, Y, and K) and colors (L ^* , a ^{*) of} a print image generated based on the print data by the reference printer ^. , B ^* value) is stored, and a color sample printed based on the print image data by the reference printer is prepared.

When the user selects the profile radio button 653 with the mouse 34 or the like and further selects the execute button 657, the target color acquisition unit 230 refers to the color reference profile stored in the storage unit 280, and the halftone% of the target color. color values and the corresponding print image ^{(L *, a *, b} * values) is obtained, the color of the acquired print image ^{(L *, a *, b} * value) is temporarily set to the target color .

  When the user selects the color sample radio button 654 with the mouse 34 or the like and further selects the execute button 657, the target color acquisition unit 230 instructs the image display unit 270 to display the color sample measurement auxiliary screen, and the display screen 32a. The color sample measurement auxiliary screen is displayed above.

  FIG. 10 is a diagram illustrating an example of a color sample measurement auxiliary screen.

On the color sample measurement auxiliary screen 660, a print image 661 represented by the print image data is displayed, and a portion 662 where the target color is set on the print image 661 is highlighted. When the user connects the colorimeter to the workstation 30 and sets the colorimeter at a position corresponding to the highlighted portion 662 on the color sample prepared in advance, the color at that position is measured. Then, the colorimetric values (L ^* , a ^* , b ^* values) are transmitted to the target color acquisition unit 230 via the I / O interface 306 in FIG. In the target color acquisition unit 230, the transmitted colorimetric color is provisionally set as the target color.

  When the target color is temporarily set, the temporarily set target color is displayed on the target color display unit 656 of the target color selection screen 650 shown in FIG.

  When the target color is provisionally set for all the target colors displayed on the target color selection screen 650 and the user selects the end button 658 using the mouse 34 or the like, the target color acquisition unit 230 temporarily determines the target color. The target color is determined as the final target color (step S3 in FIG. 5). The target color acquisition unit 230 corresponds to an example of the target color acquisition unit referred to in the present invention. The determined target color is transmitted to the color prediction unit 240.

  When the target color is determined, the attention color setting screen 500 shown in FIG. 6 is displayed again on the display screen 32a shown in FIG. When the user selects the automatic adjustment button 543 with the mouse 34 or the like, the calculation of the initial print density of ink is started. First, a determination selection screen for selecting a determination condition for determining that the print color in the target color is adjusted to the target color in the target color when the print image is generated based on the print image data in the printing machine 20 Is displayed.

  FIG. 11 is a diagram illustrating an example of the determination selection screen.

  The determination selection screen 700 includes a color difference input unit 714 for inputting a color difference determination criterion for determining that the print color has been adjusted to the target color, and an average color difference radio for performing determination using the average color difference of each target color. The determination is performed using the button 711, the weighted average color difference radio button 712 for performing determination using the average color difference weighted according to the priority for each target color, and the largest color difference among the color differences of each target color. There are provided a maximum color difference radio button 713, an OK button 715 for confirming the setting contents, and a cancel button 716 for canceling the setting.

  When the user uses the mouse 34 or the like to select the color difference of the determination criterion and the type of color difference to be used and selects the OK button 715, the selection content is transmitted from the operation unit 260 to the color prediction unit 240.

  In the color prediction unit 240, calculation of the initial print density of the ink is started.

  First, the printing color in the target color when the printing image is generated based on the printing image data in the printing machine 20 is predicted (step S4 in FIG. 5).

  Here, the description of the flowchart of FIG. 5 is temporarily interrupted, and a printing color prediction method will be described.

  Prior to printing, when the control device 10 generates a print image based on print image data in which the print density of ink of the printing machine 20 is 100% of the halftone value of each color of C, M, Y, and K The print color of the print image is set to a standard print density that becomes a predetermined standard color. Hereinafter, a state where the ink printing density is set to the standard printing density is referred to as a standard state.

  When the printing machine 20 is set to the standard state, the printing machine 20 prints a chart image in which a plurality of patches having different colors are arranged on the basis of the chart image data prepared in advance. Each patch is used to measure colors.

  Next, the print density of each of the CMYK inks was changed to an optical density of -0.2, -0.1, +0.1, and +0.2 as described above with respect to the standard print density. A chart image is printed based on the chart image data. Hereinafter, a state in which the ink printing density is changed from the standard printing density is referred to as a changed state. In this example, each color of CMYK is set to a change state of “standard printing density−0.2”, “standard printing density−0.1”, “standard printing density + 0.1”, and “standard printing density + 0.2”. Thus, a total of 16 chart images are printed. Each patch on the generated chart image is also measured.

Here, the print color R of the patch when the print density of each of the CMYK inks is changed by a desired fluctuation amount with respect to the standard print density is the color measurement of the patch printed by the printing machine 20 set to the standard state. The value is R _(std) , the difference between the colorimetric value of the patch when the print density of the ink of only C color is changed and the colorimetric value of the patch printed at the standard print density is R _ΔC , and the ink of only M color R _{ΔM is} the difference between the colorimetric value of the patch when the print density is changed and the colorimetric value of the patch printed at the standard print density, and the colorimetry of the patch when the print density of only Y-color ink is changed The difference between the measured value and the color measurement value of the patch printed at the standard print density is R _ΔY , and the patch color measurement value and the measurement of the patch printed at the standard print density when the print density of only the K color ink is changed If the amount of color value difference is _RΔK ,
R = R _(std) + _RΔC + _RΔM + _RΔY + _RΔK (1)
Can be obtained approximately. By substituting the colorimetric values obtained by measuring the colors of the chart image printed in the standard state and the patches of each of the 16 chart images in the changed state into Equation (1), the print density of the ink is determined for each patch. Correspondence between (standard printing density ± variation) and patch printing color R is obtained. That is, the print color of the patch can be predicted from the halftone value of the patch and the print density of the ink. In addition, by executing the interpolation process for the ink print density, the print color R corresponding to the print density of the fine variation ink is also calculated, and further, the interpolation process is executed for the halftone value of the patch. The printing color R for a number of colors is also calculated.

  The correspondence relationship between the halftone value of the original color calculated as described above, the ink printing density, and the predicted printing color is stored in the storage unit 280.

  In step S4 of FIG. 5, the color prediction unit 240 shown in FIG. 4 determines the temporary ink printing density common to each target color, and based on the correspondence stored in the storage unit 280, The print color of each target color corresponding to the print density of the ink and the halftone value of each target color is acquired.

  As described above, the print color of the target color is predicted.

  When the print color is predicted, it is determined whether or not the color difference between the print color and the target color is larger than the reference color difference (step S5 in FIG. 5). When only one target color is set, the color difference between the target color and the print color is determined as the determination target color difference. When a plurality of target colors are set, and the average color difference radio button 711 is selected on the determination selection screen 700 shown in FIG. 11, the average value of the color differences between the print color and the target color in each of the plurality of target colors. Is determined as the color difference to be determined, and the weighted average color difference radio button 712 is selected, the higher the priority of each target color with respect to the color difference between the print color and the target color in each of the plurality of target colors, When the average value is calculated with a large weight, the calculated weighted average value is determined as the color difference to be determined, and the maximum color difference radio button 713 is selected, the print color and the target color for each of the plurality of target colors The largest color difference is determined as the determination target color difference. Further, it is determined whether the color difference to be determined is larger than the reference color difference input by the color difference input unit 714.

  When the color difference to be determined is larger than the reference color difference (step S5 in FIG. 5: Yes), the print density of ink is changed by a predetermined value (step S6 in FIG. 5), and the print color prediction in step S4 is executed again. To do. Further, the color difference between the target color and the target color at the new ink printing density is determined.

  A series of processes of changing the printing density of ink (step S6 in FIG. 5), printing color prediction (step S4 in FIG. 5), and color difference determination (step S5 in FIG. 5), the color difference to be determined is less than the reference color difference. The process is repeated until convergence (step S5: No in FIG. 5) or until a predetermined maximum number of repetitions (eg, 3000) is reached. The color prediction unit 240 corresponds to an example of a color estimation unit according to the present invention and also corresponds to an example of a density calculation unit according to the present invention. When the change of the ink print density is completed, the ink print density at the end of the change is provisionally determined as the initial print density.

  In the present embodiment, specifically, the method of changing the print density of ink so that the color difference to be determined converges to a reference color difference or less is based on the print density adjustment amount of each color of C, M, Y, and K. The color difference is estimated by predicting the print colors in all combinations of print densities while changing in a fine adjustment step (for example, 0.025) within a predetermined adjustment width (for example, from −0.15 to +0.15). A brute force calculation method (when using a print density of 13 steps with C, M, Y, and K4 colors, 28561 print colors are calculated) and C, M, Y, and K inks While changing the print density adjustment amount in a rough adjustment step (for example, 0.05) within a predetermined adjustment range (for example, from −0.15 to +0.15), the print color and the color difference are calculated, The color difference calculated in It can be applied a method of adjusting the print density adjusting amount fine adjustment step only when it becomes smaller than the out color difference. In the present embodiment, (1) the print color and the color difference are calculated while changing in a coarse adjustment step (0.05) within a predetermined adjustment range (from −0.15 to +0.15), and (2) When the new color difference is smaller than the color difference calculated so far, printing of 8 patterns in which each color of C, M, Y, K is changed in a fine adjustment step (0.025) in the plus direction and the minus direction respectively. Calculate color and color difference. (3) Further, using the print density adjustment amount in the direction in which the smallest color difference among the calculated 8 color differences is calculated, the process returns to the process (2) to calculate the print color and the color difference. In this way, the process of determining the initial print density by first changing the print density adjustment amount in the coarse adjustment step, determining the adjustment direction of the print density adjustment amount, and then changing the print density adjustment amount in the fine adjustment step. Time can be increased.

  When the initial print density is provisionally determined, the color prediction unit 240 transmits a display instruction for the calculation result display screen to the image display unit 270, and the calculation result display screen is displayed on the display screen 32a.

  FIG. 12 is a diagram illustrating an example of a calculation result display screen.

  Part (A) of FIG. 12 shows a calculation result display screen 720 displayed when the initial print density converges. Part (B) of FIG. 12 shows that the initial print density does not converge. A calculation result display screen 730 displayed when the maximum number of iterations is reached is shown.

  The calculation result display screens 720 and 730 include result display units 721 and 731 on which initial print densities of C, M, Y, and K colors and a color difference between the target color and the print color are displayed, and a result display unit 721. OK buttons 722 and 733 for confirming the initial print density displayed in 731 and cancel buttons 723 and 734 for canceling the setting of the initial print density are displayed, and the calculation result shown in part (B) of FIG. On the display screen 730, a warning message 732 “Color difference determination condition is not satisfied” is also displayed.

  When the user selects an OK button 722 or 733 with the mouse 34 or the like, the initial print density is transmitted from the color prediction unit 240 shown in FIG. 4 to the density adjustment unit 250.

  The density adjustment unit 250 generates a predicted image of a print image to be printed in the printing system 1 based on the print density and print image data of each of the CMYK inks transmitted from the color prediction unit 240. In addition, the density adjustment unit 250 notifies the image display unit 270 of the predicted image and instructs to update the attention color setting screen 500 shown in FIG.

  The image display unit 270 replaces the print image 510 on the target color setting screen 500 shown in FIG. 6 with an expected image, and the color information display unit 520 displays the halftone value, target color, priority of each target color already set. The predicted print color, the color difference between the target color and the print color are displayed, and the calculated initial print density of the ink is displayed in the density manual adjustment unit 530. When the user finely adjusts the initial print density of the ink manually, the user changes the value on the density manual adjustment unit 530 using the mouse 34 or the like. The image display unit 270 corresponds to an example of the display unit referred to in the present invention.

  When the user selects the execution button 544 with the mouse 34 or the like, the initial print density of ink is transmitted from the density adjustment unit 250 in FIG. 4 to the control device 10, and the control device 10 prints the ink on the printing machine 20. The density is set to the initial print density (step S7 in FIG. 5).

  When the initial printing density of the ink is set, the trial printing is repeated while finely adjusting the printing density of the ink in the control device 10, and the colorimetric value obtained by the colorimeter 11 reaches the target color and printing of the ink is performed. When the density is stabilized, the start of printing is transmitted from the workstation 30 to the control device 10 and actual printing is performed. In this embodiment, since the initial print density of the ink close to the target print density for realizing the target color is set, the time until the ink print density is stabilized can be increased, and Occurrence can be suppressed.

  Above, description of 1st Embodiment of this invention is complete | finished and 2nd Embodiment of this invention is described. The second embodiment of the present invention has the same configuration as that of the first embodiment shown in FIG. 4, but only the method of setting a target color in the target color setting unit 220 is different from the first embodiment. Therefore, FIGS. 4, 6 and 7 are also used in the description of the present embodiment, and only differences from the first embodiment will be described.

  Also in this embodiment, when the area radio button 612 shown in FIG. 6 is selected and an area including an important color is selected on the print image 510 of the target color setting screen 500, the position information of the area is shown in FIG. This is transmitted from the operation unit 260 to the target color setting unit 220. In the target color setting unit 220 of the present embodiment, a plurality of halftone data representing all pixels in the area indicated by the position information transmitted from the operation unit 260 is analyzed in the print image data, and the halftone value is determined. The total number of pixels that are the same is calculated. Furthermore, a predetermined number (two in this example) of halftone values having a large total number is selected, and the color represented by the selected halftone value is set as the target color. By setting the color with high appearance frequency in the area as the attention color, the user can easily set the important color as the attention color even when the important colors are dispersed in the area. Can do.

  Also, the attention color setting unit 220 gives a higher priority to the plurality of set attention colors in descending order of the area of the image portion having the attention color on the print image 510. Usually, important colors often occupy a large area on a printed image, and priorities are automatically assigned according to the area of each color, so even if you do not have skilled knowledge about printing It is possible to obtain a print image that is visually appealing in which important colors are expressed by target colors.

  Above, description of 2nd Embodiment of this invention is complete | finished and 3rd Embodiment of this invention is described. The third embodiment of the present invention has the same configuration as that of the first embodiment shown in FIG. 4, but the processing in the color prediction unit 240 is different from that of the first embodiment. Therefore, FIG. 4 and FIG. 5 are also used in the description of the present embodiment, and only differences from the first embodiment will be described.

  In the present embodiment, the processing contents in the print color prediction process in step S4 in FIG. 5 are different from those in the first embodiment.

  Also in this embodiment, prior to printing, the control device 10 sets the printing density of the ink of the printing machine 20 to the standard printing density, and the printing machine 20 prints a chart image based on the chart image data.

  Next, the chart image is displayed in a state in which the print density of each of the CMYK inks is changed to -0.2, -0.1, +0.1, +0.2 in terms of the optical density with respect to the standard print density. Each of the CMYK colors is printed, and each of the CMYK colors is set to a change state of “standard print density−0.2”, “standard print density−0.1”, “standard print density + 0.1”, and “standard print density + 0.2”. A total of 16 chart images are printed.

  As described above, the chart image at the standard print density and the 16 chart images at the changed print density are printed, and each patch in the chart image is measured by the colorimeter. Further, in addition to the color of each patch at the standard print density (hereinafter referred to as a reference color), the amount of change in the print density after the change to the standard print density, and the color and reference color of each patch at the print density after the change The correspondence relationship with the difference is stored in the storage unit 280. In the present embodiment, the density conversion values X, Y, and Z of the colorimetric values of the patches at the standard print densities C, M, Y, and K are associated with the input network% values C, M, Y, and K of the patches. The standard profiles, the print density fluctuations Dc, Dm, Dy, Dk, the print color differences ΔX, ΔY, ΔZ for each patch and the input network% values C, M, Y, K for each patch. The saved difference profile is saved. Thus, by storing only the correspondence obtained by actually measuring the color of the patch, the required memory capacity can be reduced.

  When printing is actually performed, as in the first embodiment, the target color in the image is set (steps S1 and S2 in FIG. 5), and the target color in the target color is acquired (step S3 in FIG. 5). Then, the printing density of the temporary ink is determined, the printing color of the target color at the printing density of the temporary ink is predicted (step S4 in FIG. 5), and the color difference between the predicted printing color and the target color is determined. (Step S5 in FIG. 5). Until the color difference to be determined converges below the reference color difference (step S5 in FIG. 5: No), the temporary ink printing density is changed (step S6 in FIG. 5), and the target color in the new temporary ink printing density is changed. Print color prediction (step S4 in FIG. 5) and color difference determination (step S5 in FIG. 5) are repeated. In the present embodiment, the print density of the ink that realizes the target color is calculated, and the calculated print density is set to the temporary ink print density in the initial state until the color difference converges below the reference color difference. Acceleration of processing time is being measured.

  FIG. 13 is a diagram showing a flow of a series of processes for calculating the printing density of ink.

  First, of the standard profile and the difference profile stored in the storage unit 280, the corresponding part close to the input color C, M, Y, K value of the target color in which the patch input network% values C, M, Y, K are set. Only is extracted. Subsequently, by executing interpolation processing, a table showing the correspondence between the print density fluctuation amounts Dc, Dm, Dy, Dk in the target color and the print color differences ΔX, ΔY, ΔZ with respect to the reference color is created. (Step S11 in FIG. 13).

  FIG. 14 is a conceptual diagram of the created table.

  The axis shown in FIG. 14 indicates the amount of variation in the print density of each color of C, M, Y, and K with respect to the standard print density. The center point plotted with a black circle indicates the standard print density, and the value of the center point indicates the print color (reference color) of the target color when the ink print density is set to the standard print density. Also, each point plotted with a white circle indicates the printing density when the printing density of each color ink of CMYK is independently changed with respect to the standard printing density, and the value of each point is the printing density of the ink Indicates the difference between the print color of the target color and the standard color in a state where the print density indicated by each point is set. For example, the print color of the target color at the print density of the ink indicated by the dots plotted with hatched circles can be calculated by substituting the values of the points plotted with black circles and white circles into the above equation (1). it can. In addition, when the print density intervals when the ink density of each of the CMYK inks is changed independently of the standard print density are rough, the interpolation process is executed for the ink print density as in the first embodiment. By doing so, the amount of variation in the printing density of the ink may be made fine to create the table.

Here, in the above-described equation (1), the difference between the two predicted printing colors R1 and R2 is the measurement of the patch at the standard printing density with respect to the variation in printing density of the inks of C, M, Y, and K colors. It is represented by the sum of the difference between the color value and the colorimetric value of the patch at the ink printing density after the change,
R1-R2 = Σ (R1 _Color -R2 _Color ) (1_1)
It becomes. When the colorimetric values (L *, a *, b *) are expressed by the colorimetric density values (-log (X), -log (Y), -log (Z)), the standard printing shown in the table of FIG. Difference Δc-log of the print colorimetric density of the target color in the print density of the ink after the change with respect to the print colorimetric density of the target color at the standard print density and the variation amount Dc, Dm, Dy, Dk The correspondence relationship with (X), Δ-log (Y), and Δ-log (Z) is expressed by the following determinant (2).

Also, Equation (2) is
X = JD Formula (2_1)
Δ−log (X), Δ−log (Y), Δ−log (Z) between the print colorimetric density of the target color in the actual standard print density and the colorimetric density value of the target color in the target color ) Is substituted for the left side X, the solution D is the density difference between the ink print density and the standard print density for realizing the target color. However, D is 3-dimensional, X is because it is four-dimensional, D = J - ^X become inverse matrix obtaining a unique solution J ^- is absent. Therefore, the general inverse matrix J ⁺ is obtained by adding the following two conditions,
D ′ = J ⁺ X Expression (2_2)
The approximate solution D ′ close to the exact solution D is uniquely determined by the determinant.

(Condition 1) Since the approximate solution D ′ is different from the exact solution D, JD ′ ≠ X and an error e (= JD′−X) is generated. A variation D ′ of the print density that minimizes the square of the error e is calculated. (Least squares solution)
(Condition 2) Since the fluctuation amount D of the printing density is a difference from the standard printing density, the smaller the fluctuation amount D is, the better the stability of the adjusted printing press is. For this reason, the fluctuation amount D ′ having the smallest absolute value is calculated. (Minimum norm solution)
Also, the spectral density distributions of C, M, and Y colors and the color matching functions of X, Y, and Z colors are mainly associated with C and X, M and Y, and Y and Z. For example, a determinant ( 2) Although there is a relationship that Δ-logX changes greatly when Dc in FIG. 4 changes, all the colorimetric density values X, Y, and Z change when the print density of K color is changed. For this reason, even when only the print density Dk of the K ink is originally changed, the solution D ′ calculated under the above-mentioned norm minimum condition prints the C, M, and Y color inks. The density Dc, Dm, Dy is changed, and the K color does not change much.

  The determinant (3) is a determinant obtained by transposing the Dk component indicating the variation amount of the K color to the left side in the determinant (2).

  The Dk component relating to the K color in the determinant (2) is separated, and first the Dk component is set to “0”. By calculating the approximate solution D ′ under the condition that only the C, M, and Y colors are changed, and then adjusting the K color individually, the accuracy of the solution can be improved.

  Further, when a plurality of target colors and target colors for each of the plurality of target colors are set, the expression (2_1) can be expressed as Xn “print colorimetric density of target color_n at standard print density” for each of the plurality of target colors. And the target color_n is a difference_n between the measured color density value of the target color_n ”, but since the print density of ink set in one printing is one, the calculated solution D ′“ target color n ” The density difference between the ink print density n and the standard print density for realizing the above is one regardless of the target color and the target color. If the weight added to each Xn is Wn,

A plurality of simultaneous equations shown in Expression (4) are created. The weight Wn of each color is a diagonal matrix having the same diagonal component. When Expression (4) is expressed by a determinant,

It becomes. Create simultaneous equations showing the correspondence between multiple target colors, and calculate the print density common to multiple target colors, even when multiple target colors are set, realize those target colors The print density can be calculated efficiently.

The Moore-Penrose type general inverse matrix J ⁺ is calculated under the above conditions, and an approximate solution D ′ of the solution D indicating the variation amount of the print density of the ink for realizing the target color with respect to the standard print density. Is obtained (step S12 in FIG. 13).

  Subsequently, the approximate solution D ′ calculated by the equation (2_2) is substituted into the solution D of the equation (2_1) so that the ink print density is changed from the standard print density by the fluctuation amount D ′. A printing color X ′ when the color is printed is calculated.

  Further, a difference between the calculated print color X ′ and the target color X is calculated (step S13 in FIG. 13), and an average color difference between them is obtained.

  At this time, if the calculated average color difference is smaller than the currently stored average color difference, the variation D ′ (Dk, Dc, Dm, Dy) and the average color difference are held (step in FIG. 13). S14). In the present embodiment, an example is shown in which the variation amount D ′ when the average color difference is minimized, but the evaluation condition in step S14 is the variation amount D when the maximum color difference of the target color is minimized. It may hold '.

  Subsequently, the K color variation amount Dk is changed (step S15 in FIG. 13), the print color X ′ is calculated, the difference between the print color X ′ and the target color X is calculated (step S13 in FIG. 13), and the average color difference is calculated. Is calculated, and the variation D ′ (Dk, Dc, Dm, Dy) and the average color difference are held (step S14 in FIG. 13). In the present embodiment, the variation amount K of the K color is changed by “0.025” steps from “−0.15 to +0.15”, and the processing from step S13 to step S15 is repeated. It is.

  When the processing in all steps is completed (step S15 in FIG. 13: Yes), the fluctuation amount D ′ (Dk, Dc, Dm, Dy) held at the present time is set as an initial solution (step S16 in FIG. 13). .

In addition, until the predetermined specified number of times is reached (step S17 in FIG. 13), the variation D ′ (Dk, Dc, Dm, Dy) set as the initial solution is substituted into the expression 2_1, and a new general matrix J ⁺ Is calculated (step S12 in FIG. 13), and further, the processes from step S13 to step S16 are executed, whereby the update of the initial solution is repeated.

  When the predetermined prescribed number of times is reached (step S17 in FIG. 13: Yes), the initial solution set at that time is determined as the temporary ink printing density in step S6 in FIG. 5 (step S18 in FIG. 13). .

  Subsequently, the printing density when the target color is realized is searched while changing the printing density of each of the plurality of inks, starting from the determined printing density of the temporary ink.

  FIG. 15 is a diagram illustrating the relationship between the printing density of temporary ink and the search direction.

  In the present embodiment, the search is performed by changing the print density of each of the C, M, Y, and K colors by 0.025 starting from the print density of the temporary ink indicated by the black circle.

  FIG. 16 is a diagram showing a flow of a series of processes for searching for the print density when the target color is realized, starting from the temporary ink print density.

  First, starting from the printing density of the temporary ink (step S31 in FIG. 16), all eight printing densities are set by changing the C, M, Y, and K colors by 0.025 for each color. Subsequently, the difference between each print density and the standard print density is substituted into Equation 2_1 to obtain the print color of the target color at each print density, and the average color difference between the print color and the target color is calculated. (Step S32 in FIG. 16).

  When the calculated average color difference is smaller than the average color difference in the printing density of the temporary ink (step S33 in FIG. 16), the variation amount is added to the printing density of the temporary ink (step in FIG. 16). S34), the print density for realizing the minimum average color difference is set to the print density of the new ink. Furthermore, when the minimum average color difference at the present time is smaller than the preset allowable color difference (step S35 in FIG. 16: Yes), the final print density of the temporary ink at the current time is realized as the target color. This is determined as the printing density of the ink (step S37 in FIG. 16).

  If the current minimum average color difference is equal to or greater than the allowable color difference (step S35: No in FIG. 16), whether the predetermined number of times is reached (step S36 in FIG. 16), or the average color difference is the allowable color difference. 16 (step S35 in FIG. 16), the average color difference between the print color and the target color at the peripheral print density starting from the print density of the new temporary ink is calculated (step S32 in FIG. 16). The comparison of the average color difference (Step S33 in FIG. 16) and the update of the temporary ink printing density (Step S34 in FIG. 16) are repeated.

  FIG. 16 also shows an example of searching for a print density that minimizes the average color difference between the print color and the target color as the print density when the target color is realized. You may search for the minimum print density.

As described above, by using the general inverse matrix J ⁺ , the print density of the ink that realizes the target color is calculated, and the final print density is searched from the predicted print density as a starting point. It is possible to reduce the trouble that gets stuck and to speed up the processing time.

  Here, the example of setting the print density of each of the CMYK four color inks has been described above. However, the present invention sets, for example, the print density of each of the special color inks in addition to the CMYK four colors. It may be.

  In the above, an example in which ink is used as a color material has been described. However, the color material referred to in the present invention may be, for example, a toner for an electrophotographic printer.

1 is an overall configuration diagram of a printing system in which an embodiment of the present invention is incorporated. It is a hardware block diagram of a workstation. It is a conceptual diagram which shows CD-ROM. It is a functional block diagram of a printing density adjusting device. It is a flowchart figure which shows the flow of a series of processes until the printing density of ink is set. It is a figure which shows an example of an attention color setting screen. It is a figure which shows an example of the designation | designated method selection screen. It is a figure which shows an example of a setting color information screen. It is a figure which shows an example of a target color selection screen. It is a figure which shows an example of a color sample measurement auxiliary | assistant screen. It is a figure which shows an example of the determination selection screen. It is a figure which shows an example of a calculation result display screen. It is a figure which shows the flow of a series of processes which calculate the printing density of ink. It is a conceptual diagram of the created table. It is a figure which shows the relationship between the printing density of temporary ink, and a search direction. It is a figure which shows the flow of a series of processes which search printing density when a target color is implement | achieved from the printing density of temporary ink.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing system 10 Control apparatus 20 Printing machine 30 Workstation 31 Main body apparatus 32 Image display apparatus 33 Keyboard 34 Mouse 301 CPU
302 Main Memory 303 Hard Disk Device 304 FD Drive 305 CD-ROM Drive 306 I / O Interface 100 Print Density Adjustment Program 110 Image Acquisition Unit 120 Target Color Setting Unit 130 Target Color Acquisition Unit 140 Color Prediction Unit 150 Density Adjustment Unit 160 Operation Unit 170 Image display unit 200 Print density adjustment device 210 Image acquisition unit 220 Attention color setting unit 230 Target color acquisition unit 240 Color prediction unit 250 Density adjustment unit 260 Operation unit 270 Image display unit 280 Storage unit

Claims (18)

An image for obtaining print image data representing a print image to be printed by a printing system in which the print density of each of the color materials of a plurality of colors is set and the color material is used at the print density to print an image based on the image data A data acquisition unit;
A location designating unit for designating a location on the print image represented by the print image data obtained by the image data obtaining unit;
A target color acquisition unit for acquiring a target color for the color of the part;
Based on chart image data representing a chart image in which patches of a plurality of colors are arranged, the printing system prints the chart image while changing the printing density to a series of printing densities for each color of the plurality of colors. Based on the correspondence between the color of each patch obtained by printing at a density and the print density, and the provisional print density designated for each of a plurality of color materials, the print image data and the provisional print A color estimation unit that estimates a printing color at the location by the printing system based on density; and
The color estimation unit is used to determine the print densities of the color materials of the plurality of colors so that the target color acquired by the target color acquisition unit is realized at the location by the printing system based on the print image data. A density calculation device comprising a density calculation unit for calculating the density. The location designation unit designates a plurality of locations with different priorities as the location,
The target color acquisition unit acquires each target color for each of the plurality of locations,
The density calculation unit has a common print density at which the target colors of the plurality of locations are realized by the printing system, an implementation accuracy at a location having a relatively high priority among the plurality of locations, The concentration calculation apparatus according to claim 1, wherein the concentration calculation is performed with an emphasis on realization accuracy at a relatively low location.   The location designation unit displays the print image based on the print image data, and designates the location according to a selection operation for selecting the location on the displayed print image. Item 3. The concentration calculation apparatus according to Item 1 or 2. The location designating unit designates an area on the print image;
The density calculation apparatus according to claim 1, wherein the target color acquisition unit acquires a target color with respect to an average color in the region. The location designating unit designates an area on the print image;
The density calculation apparatus according to claim 1, wherein the target color acquisition unit acquires a target color for a color that appears most frequently in the region. The print image data is a set of color data representing the color of each point on the print image,
The location designating unit designates, as the location, one or more point sets selected from those having a larger number of points among a set of points on the print image having the same color data. The concentration calculation apparatus according to claim 1, wherein: The print image data is a set of color data representing the color of each point on the print image,
3. The location designation unit designates each point on the print image in which a color is represented by the same color data as color data representing a predetermined important color as the location. The concentration calculation apparatus described.   The concentration calculation apparatus according to claim 2, wherein the location specifying unit assigns a high priority to each of the plurality of locations in descending order of area.   The target color acquisition unit acquires the color of the portion on the print image when the print image is printed by a printing system different from the printing system as the target color. The density | concentration calculation apparatus of any one of Claims 1-8.   The target color acquisition unit calculates the color of the location based on a correspondence relationship between the print data and the color on the print image when the print image is printed by the another printing system, and the target color The density calculation device according to claim 9, wherein the density calculation device is acquired as follows.   The target color acquisition unit acquires, as the target color, a colorimetric value obtained by measuring the location on a printed material obtained by printing the print image with the another printing system. The concentration calculation apparatus according to claim 9.   A display unit configured to display an expected image of a print image obtained by printing by the printing system based on the print density of each of the color materials calculated by the density calculation unit and the print image data; The concentration calculation apparatus according to claim 1, wherein: Each obtained by printing the chart image with the print density of the printing system set to the standard print density when the print color of the image printed based on the predetermined image data becomes a predetermined standard color Obtained by printing the chart image by setting the print density of the printing system to a series of print densities that change from the standard print density for each color of the reference color of the patch and the plurality of color materials. A storage unit that stores a color difference between each patch color with respect to the reference color and a correspondence relationship between the print density and the standard print density;
The color estimation unit receives the provisional print density of each of the color materials of the plurality of colors and the designation of the location, acquires a related portion corresponding to the location among the correspondence stored in the storage unit, 13. The density calculation apparatus according to claim 1, wherein a printing color at the location is estimated by an interpolation process using a reference color of each patch and the related portion. .   The density calculation unit has a determinant Ax = y corresponding to the correspondence stored in the storage unit (where A is a matrix, x is a vector representing a density difference, and y is a vector representing a difference in print color). ) For the exact solution obtained by solving for x, a solution x ′ satisfying the norm minimum and least squares solution is uniquely given by the determinant x ′ = A′y. Substituting the difference between the color of the part and the target color into y of x ′ = A′y to obtain a solution of the density difference, and the density shifted from the standard density by the obtained density difference is the temporary print density As a starting point, by repeating the designation of the temporary print density for the color estimation unit and the acquisition of the print color estimated by the color estimation unit, the print density at which the target color is realized as the print color at the location is obtained. 14. The concentration calculation device according to claim 13, wherein the concentration calculation device is a search. .   When the target color acquisition unit acquires a plurality of target colors for each of a plurality of locations, the density calculation unit determines the color of each location and the target color for the location in y of the determinant x ′ = A′y. The simultaneous equation is created by substituting the difference between and a solution of the density difference common to the plurality of target colors by solving the simultaneous equation, and a density shifted from the standard density by the obtained density difference is obtained. The density calculation apparatus according to claim 14, wherein the plurality of target colors are searched for a print density that is realized as a print color at each of the plurality of locations as a starting point of the temporary print density. An image for obtaining print image data representing a print image to be printed by a printing system in which the print density of each of the color materials of a plurality of colors is set and the color material is used at the print density to print an image based on the image data A data acquisition unit;
A location designating unit for designating a location on the print image represented by the print image data obtained by the image data obtaining unit;
A target color acquisition unit for acquiring a target color for the color of the part;
Based on chart image data representing a chart image in which patches of a plurality of colors are arranged, the printing system prints the chart image while changing the printing density to a series of printing densities for each color of the plurality of colors. Based on the correspondence between the color of each patch obtained by printing at a density and the print density, and the provisional print density designated for each of a plurality of color materials, the print image data and the provisional print A color estimation unit that estimates a printing color at the location by the printing system based on density; and
The color estimation unit is used to determine the print densities of the color materials of the plurality of colors so that the target color acquired by the target color acquisition unit is realized at the location by the printing system based on the print image data. A concentration calculation unit for calculating
A density setting device, comprising: a density setting unit that sets, in the printing system, the printing density of each of the color materials calculated by the density calculation unit. Executed in a computer, on the computer,
An image for obtaining print image data representing a print image to be printed by a printing system in which the print density of each of the color materials of a plurality of colors is set and the color material is used at the print density to print an image based on the image data A data acquisition unit;
A location designating unit for designating a location on the print image represented by the print image data obtained by the image data obtaining unit;
A target color acquisition unit for acquiring a target color for the color of the part;
Based on chart image data representing a chart image in which patches of a plurality of colors are arranged, the printing system prints the chart image while changing the printing density to a series of printing densities for each color of the plurality of colors. Based on the correspondence between the color of each patch obtained by printing at a density and the print density, and the provisional print density designated for each of a plurality of color materials, the print image data and the provisional print A color estimation unit that estimates a printing color at the location by the printing system based on density; and
The color estimation unit is used to determine the print densities of the color materials of the plurality of colors so that the target color acquired by the target color acquisition unit is realized at the location by the printing system based on the print image data. A density calculation program characterized by constructing a density calculation unit for calculating the density. Executed in a computer, on the computer,
An image for obtaining print image data representing a print image to be printed by a printing system in which the print density of each of the color materials of a plurality of colors is set and the color material is used at the print density to print an image based on the image data A data acquisition unit;
A location designating unit for designating a location on the print image represented by the print image data obtained by the image data obtaining unit;
A target color acquisition unit for acquiring a target color for the color of the part;
Based on chart image data representing a chart image in which patches of a plurality of colors are arranged, the printing system prints the chart image while changing the printing density to a series of printing densities for each color of the plurality of colors. Based on the correspondence between the color of each patch obtained by printing at a density and the print density, and the provisional print density designated for each of a plurality of color materials, the print image data and the provisional print A color estimation unit that estimates a printing color at the location by the printing system based on density; and
The color estimation unit is used to determine the print densities of the color materials of the plurality of colors so that the target color acquired by the target color acquisition unit is realized at the location by the printing system based on the print image data. A concentration calculation unit for calculating
A density setting program that constructs a density setting unit that sets, in the printing system, the printing density of each of the color materials calculated by the density calculation unit.

Images