JP2006157294A - Method and apparatus of processing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus of processing an image which can duplicate a target color faithfully without causing a trouble at the time of outputting other job from a printer since a printer profile itself is not rewritten. <P>SOLUTION: When the target color is set from a client 3, a front end server 1 and a printer engine 2 form color patch data of device non-depending color according to the target color by a color patch formation part 17, a color management processor 18 converts it into device color patch data using a printer profile, and an output unit 24 outputs transformation data from a printer, and forms a device color patch chart. Then, the colorimetry of the charge is performed by a color sensor 26. A device color estimator 20 presumes a device color from a colorimetry result. A spot color correction table regulation part 21 creates the spot color correction table using the estimated value of the device color. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing method and an image processing apparatus for adjusting a printer profile used when a color image is output from a color printer.

  A spot color matching technique is known as a technique for faithfully reproducing a target color using a color printer. This technique is based on the premise that the printer profile is properly adjusted in the initial state. If the printer state is affected by environmental fluctuations, stable output may not be obtained. A possible solution is to regenerate the printer profile. However, since the regeneration generates a profile optimized for the entire color reproduction space of the printer, there is a problem that it takes time and effort for the work.

On the other hand, the applicant inputs a target color expressed in a device-independent color space, generates a color patch chart composed of a plurality of points according to the input color, and measures the color. A method has been proposed in which the color is estimated and the initial printer profile is adjusted so that the estimated printer color corresponds to the target color (Japanese Patent Application No. 2003-403735).
JP-A-7-105344

  However, in the printer profile adjustment method as described above, the printer profile itself corresponding to the target color is rewritten. Therefore, when outputting in consideration of the consistency of the entire printer color reproduction space, job output work is performed. May cause trouble.

  The present invention has been made in consideration of such circumstances, and does not rewrite the printer profile itself, so that the target color can be faithfully reproduced without causing any trouble when outputting other jobs from the printer. An object is to provide an image processing method and an image processing apparatus.

In order to solve the above problems, the present invention provides:
An image processing method for performing spot color correction using a printer profile and outputting a color image from a printer,
A setting process for setting a target color to be corrected;
A data generation step of generating color patch data of a device-independent color according to the target color;
A conversion step of converting the color patch data into device color patch data of a printer device dependent color using the printer profile;
Generating a device color patch chart by outputting the device color patch data from the printer; and
A colorimetric process for measuring the device color patch chart;
An estimation step for estimating a device color for reproducing the target value based on a color measurement result of the device color patch chart;
And a creation step of creating a spot color correction table using the estimated value of the device color.

  Further, in the image processing method according to the present invention, the creation step creates the spot color correction table holding a difference value between the estimated value of the device color and the printer profile for reproducing the target color. It is characterized by that.

  Furthermore, the image processing method according to the present invention further includes a correction step of performing spot color correction using the spot color correction table.

Furthermore, the image processing method according to the present invention includes:
And further comprising a selection step for allowing the user to select whether spot color correction is performed by rewriting the printer profile, using the spot color correction table, or re-creating the printer profile.
In the correction step, spot color correction is performed under the condition selected in the selection step.

Furthermore, the image processing method according to the present invention includes:
The selection step may further allow the user to select not to perform spot color correction,
In the correction step, when it is selected that spot color correction is not performed in the selection step, color matching processing and calibration processing during normal output are performed.

  Furthermore, in the image processing method according to the present invention, the data generation step calculates a predetermined index corresponding to the target color in a device-independent color space grid, and includes the index in the look-up table of the printer profile. Each data of an 8-point grid is generated as the color patch data.

  Furthermore, in the image processing method according to the present invention, the estimation step uses four target data and data of a predetermined two-point grid in the eight-point grid generated as the color patch data. 1 intermediate data is estimated, two second intermediate data are estimated using the target color and two first intermediate data of the four first intermediate data, and the target color and the The device color is estimated using two pieces of second intermediate data.

  Furthermore, the image processing method according to the present invention is characterized in that the chart generation step generates an 8-point C, M, Y, K mixed color patch chart as the device color patch chart. To do.

  Furthermore, in the image processing method according to the present invention, the color measurement step measures the color of the device color patch chart using any of an RGB output color sensor, colorimeter, or densitometer. And

Furthermore, the image processing method according to the present invention includes:
A determination step of determining whether a printer profile exists;
The setting step sets the target color on condition that the printer profile exists.

Furthermore, the image processing method according to the present invention includes:
An image processing apparatus that performs spot color correction using a printer profile and outputs a color image from a printer,
Setting means for setting a target color to be corrected;
Data generating means for generating color patch data of a device-independent color according to the target color;
Conversion means for converting the color patch data into device color patch data of a printer device-dependent color using the printer profile;
Chart generating means for outputting the device color patch data from the printer to generate a device color patch chart;
Colorimetric means for measuring the device color patch chart;
Estimating means for estimating a device color for reproducing the target value based on a colorimetric result of the device color patch chart;
Creating means for creating a spot color correction table using the estimated value of the device color.

  According to the present invention, since the printer profile itself is not rewritten, the target color can be faithfully reproduced without causing any trouble when outputting other jobs from the printer.

  The details of the spot color correction process using the spot color correction table, which is the printer profile adjustment process in the network system according to an embodiment of the present invention, will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a network system according to an embodiment of the present invention. As shown in FIG. 1, a network system according to the present embodiment includes a network 4 such as a LAN or the Internet, a client 3 connected to the network 4, a front-end server 1 serving as a printer controller, and the front-end server 1. A printer engine 2 to be connected is provided.

  Here, the client 3 includes a PC body and a monitor, and has a UI function for displaying information and accepting data input to the user. The client 3 also includes a CPU and VRAM necessary for image processing, and a communication function necessary for communication on the network.

  FIG. 2 is a block diagram showing detailed configurations of the front-end server 1 and the printer engine 2 shown in FIG.

  As shown in FIG. 2, the front-end server 1 analyzes a network I / F (interface) unit 10 for connecting to the network 4, a job control unit 11 for controlling job data, and a PDL (page description language). A PDL interpreter unit 12 that generates intermediate data, an intermediate data storage unit 13 that stores intermediate data generated by the PDL interpreter unit 12, and a rendering unit that converts the intermediate data stored in the intermediate data storage unit 13 into bitmap image data 14, a communication interface unit 15 for exchanging data with the printer engine 2, a target color storage unit 16 that stores a target color that is a color value of a device-independent color space set by a user, and generated for the target color Color patch generation to generate a color patch chart composed of multiple colors 17. A color management processing unit 18 that performs color matching and calibration processing specified for a job, and a device color patch data storage unit 19 that stores device color patch data obtained by converting device-independent color patch data into printer colors A device color estimation unit 20 for estimating a color to be output by the printer in the current state based on the color measurement result of the color sensor, and a spot correction value for matching the initial printer profile to the current state A spot correction table adjustment unit 21 that generates and updates a table and a colorimetric value storage unit 22 that stores data when a color sensor reads a target color are configured. The above-described units are connected to each other via an internal bus 28 as shown in FIG.

  The color patch generation unit 17 is connected to a color patch data storage unit 17A that stores color patch data. Further, the color management processing unit 18 includes a profile storage unit 18A that stores a profile used for color matching, and a calibration one-dimensional LUT that stores a one-dimensional LUT (lookup table) among calibration data. The storage unit 18B is connected. Furthermore, a device color storage unit 20A for storing device colors is connected to the device color estimation unit 20, and a spot correction table storage unit 21A for storing spot correction tables is connected to the spot color correction table adjustment unit 21. .

  Furthermore, the job control unit 11 is connected to a job management unit 11A that performs management such as holding a job and a job analysis unit 11B that analyzes a job ticket in the job.

  On the other hand, the printer engine 2 includes a communication interface unit 23 that exchanges data with the front-end server 1, an output unit 24 that outputs patch data and the like, a color sensor control unit 25 that controls a color sensor 26 that reads patch output and the like, A colorimetric value storage unit 27 for storing data read by the color sensor 26 is connected to each other through an internal bus 29 as shown in FIG.

  FIG. 3 is a schematic diagram for explaining the flow of processing of image data in the network system according to the present embodiment. When RGB data or CMYK data is input to the color management module (CMM) 31 in normal color management processing, color matching is performed through the source profile 32 and the initial printer profile 33. Thereafter, the data is passed through the calibration one-dimensional LUT 34 and is output from the printer 35 as corrected CMYK data. Here, for example, when applying the result of spot color correction, the image data is output with reference to both the target color correction data and the initial printer profile 33 in the spot color correction table 36.

  FIG. 4 is a diagram showing an example of a spot color correction table for a certain color chart used in the network system according to the present embodiment. In this embodiment, as shown in FIG. 4, a table is divided for each color chart, and each table outputs a color name (or color number), a chromaticity corresponding to each color name, and the color chart color. A difference value (device color correction value: for example, CMYK variation difference) from the initial printer profile at the time of performing the process is stored as an item.

  FIG. 5 is a schematic diagram of a Lab color space that varies in the network system according to the present embodiment. FIG. 5 shows an 8-point grid surrounding the target colors of the printer profile look-up table (Lab → CMYK) for the target colors (L1, a1, b1). That is, before the change, the target color (L1, a1, b1) could be reproduced with the matching result (C1, M1, Y1, K1) based on the initial profile. Then, the spot color correction table is adjusted so that the matching result is (C2, M2, Y2, K2) in order to reproduce the target color (L1, a1, b1) due to printer fluctuations.

  Next, details of processing for generating a spot color correction table in the network system having the above-described configuration will be described. FIG. 9 is a flowchart for explaining a procedure for generating a spot color correction table in the network system having the configuration of FIGS. 1 and 2.

  First, the color number of the target color is input from the UI of the client 3, and the device-independent color value corresponding to the color number of the target color is acquired by referring to the spot color source profile in the profile storage unit 18A. The number is stored in the target color storage unit 16 together with the number (step S90).

  FIG. 6 is a diagram illustrating an example of a UI screen displayed when spot correction is started in step S90. That is, the display screen shown in FIG. 6 can be confirmed on the UI of the client 3, and prompts the user to select what correction method to perform by presenting the instruction content as shown on the screen to the user. . If the user selects “spot color correction: create / update spot color correction table”, the screen shown in FIG. 7 is displayed. FIG. 7 is a diagram illustrating an example of a UI screen displayed when the color chart number to be spot-corrected is selected in step S90. The user can select the color to be corrected by selecting the type and color number of the color chart shown on the screen shown in FIG. When the color number of the target color is input in this way, as described above, the device-independent color value corresponding to the color number of the target color is obtained by referring to the spot color source profile in the profile storage unit 18A. Acquired and stored in the target color storage unit 16 together with the color number.

  Next, the color patch generation unit 17 generates device-independent color patch data using the target color and the initial printer profile stored in the profile storage unit 18A (step S91). Details of the device-independent color patch data generation processing in step S91 will be described later. The generated color patch data is stored in the color patch data storage unit 17A.

  Next, the color management processing unit 18 performs color matching, and converts the device-independent color patch data stored in the color patch storage unit 17A into device color patch data using the initial printer profile (step S92). ). By this conversion, for example, the result of (C1, M1, Y1, K1) is obtained for the target color (L1, a1, b1). The converted data is stored in the device color patch data storage unit 19.

  Next, the device color patch data obtained by the conversion in step S92 is transferred to the printer engine 2, and the output unit 24 outputs a color chart output product (device color patch chart) using the device color patch data ( Step S93).

  Next, the color sensor control unit 25 uses the color sensor 26 to measure the color chart output product output in step S93 to obtain a color chart colorimetric value, and stores it in the colorimetric value storage unit 27 ( Step S94).

  Here, the color sensor 26 will be described. FIG. 8 is a diagram illustrating a configuration example of the color sensor 26 used in the network system according to the present embodiment. The color sensor 26 is configured by incorporating a light emitting element 26A such as an LED and a light receiving element 26B such as a photodiode or CdS in a holder 26C. The color sensor 26 measures the chromaticity of the patch T by irradiating the patch T on the transfer belt 30 with the light from the light emitting element 26A and receiving the reflected light from the patch T with the light receiving element 26B. . As another color sensor, for example, a color sensor as shown in FIG. 8 of JP-A-2001-324846 may be used.

  Next, the color chart colorimetric values stored in the colorimetric value storage unit 27 are transferred to the front-end server 1, and the device color estimation unit 20 reproduces the target color from the device color patch data and the color chart colorimetric values. Is estimated (step S95). For example, as a device color estimation method, interpolation calculation is performed in a device-independent color space. A specific calculation example based on estimation will be described later. The device color estimation values (C2, M2, Y2, K2) obtained here are stored in the device color storage unit 20A.

  Next, the spot color correction table adjustment unit 21 adds the initial printer to the spot color correction table so that the matching result for the target color (L1, a1, b1) becomes the device color (C2, M2, Y2, K2). A difference value (C2-C1, M2-M1, Y2-Y1, K2-K1) from the profile is written and updated (step S96). Then, the updated spot color correction table is stored in the spot color correction table storage unit 21A, and this process ends.

  Here, details of the device-independent color patch data generation processing in step S91 will be described. In step S91, as described above, the color patch generation unit 17 generates device-independent color color patch data using the target color and the initial printer profile stored in the profile storage unit 18A. FIG. 10 is a flowchart for explaining details of the device-independent color patch data generation processing in step S91 shown in FIG.

First, the input target color is set to (L1, a1, b1) (step S100). here,
0 ≦ L1 ≦ 100, −128 ≦ a1 ≦ 128, −128 ≦ b1 ≦ 128
It is.

  Next, n is a value obtained by subtracting 1 from the number of grids in the profile lookup table. For example, if the number of grids is 33, n = 32. Then, indices i, j, and k (0 ≦ i, j, k ≦ n) of the Lab color space grid shown below are calculated (step S101).

i = L1 / 100 * n
j = (a1 + 128) / 256 * n
k = (b1 + 128) / 256 * n
However, the decimal part is rounded down.

  Then, from the three-dimensional lookup table of BtoA1Tag of the initial printer profile, (i, j, k), (i, j, k + 1), (i, j + 1, k), (i, j + 1, k + 1), (i + 1, j, k), (i + 1, j, k + 1), (i + 1, j + 1, k), and (i + 1, j + 1, k + 1) index data is color patch data, and P11, P12, P13 in this order. , P14, P15, P16, P17, and P18. This completes the process of step S91.

  Next, an example of device color estimation processing in step S95 will be described in detail. First, the device color patch data of the eight color patches P11 to P18 are (C11, M11, Y11, K11) to (C18, M18, Y18, K18), respectively, and the color chart colorimetric values are (L11, a11, b11) to (L18, a18, b18). Also, P21 to P27 are intermediate data for obtaining the device color estimated value P2.

Here, when P21 is obtained from P11 and P12,
L21 = (L12−L11) * (b1−b11) / (b12−b11) + L11
a21 = (a12−a11) * (b1−b11) / (b12−b11) + a11
C21 = (C12−C11) * (b1−b11) / (b12−b11) + C11
M21 = (M12−M11) * (b1−b11) / (b12−b11) + M11
Y21 = (Y12−Y11) * (b1−b11) / (b12−b11) + Y11
K21 = (K12−K11) * (b1−b11) / (b12−b11) + K11
It becomes.

Next, when P22 is obtained from P13 and P14,
L22 = (L14−L13) * (b1−b13) / (b14−b13) + L13
a22 = (a14-a13) * (b1-b13) / (b14-b13) + a13
C22 = (C14-C13) * (b1-b13) / (b14-b13) + C13
M22 = (M14−M13) * (b1−b13) / (b14−b13) + M13
Y22 = (Y14−Y13) * (b1−b13) / (b14−b13) + Y13
K22 = (K14−K13) * (b1−b13) / (b14−b13) + K13
It becomes.

Next, when P23 is obtained from P21 and P22,
L23 = (L22-L21) * (a1-a21) / (a22-a21) + L21
C23 = (C22-C21) * (a1-a21) / (a22-a21) + C21
M23 = (M22-M21) * (a1-a21) / (a22-a21) + M21
Y23 = (Y22-Y21) * (a1-a21) / (a22-a21) + Y21
K23 = (K22−K21) * (a1−a21) / (a22−a21) + K21
It becomes.

Next, when P24 is obtained from P15 and P16,
L24 = (L16−L15) * (b1−b15) / (b16−b15) + L15
a24 = (a16-a15) * (b1-b15) / (b16-b15) + a15
C24 = (C16-C15) * (b1-b15) / (b16-b15) + C15
M24 = (M16−M15) * (b1−b15) / (b16−b15) + M15
Y24 = (Y16−Y15) * (b1−b15) / (b16−b15) + Y15
K24 = (K16−K15) * (b1−b15) / (b16−b15) + K15
It becomes.

Next, when P25 is obtained from P17 and P18,
L25 = (L18-L17) * (b1-b17) / (b18-b17) + L17
a25 = (a18-a17) * (b1-b17) / (b18-b17) + a17
C25 = (C18-C17) * (b1-b17) / (b18-b17) + C17
M25 = (M18-M17) * (b1-b17) / (b18-b17) + M17
Y25 = (Y18-Y17) * (b1-b17) / (b18-b17) + Y17
K25 = (K18-K17) * (b1-b17) / (b18-b17) + K17
It becomes.

Next, when P26 is obtained from P24 and P25,
L26 = (L25−L24) * (a1−a24) / (a25−a24) + L24
C26 = (C25-C24) * (a1-a24) / (a25-a24) + C24
M26 = (M25−M24) * (a1−a24) / (a25−a24) + M24
Y26 = (Y25-Y24) * (a1-a24) / (a25-a24) + Y24
K26 = (K25−K24) * (a1−a24) / (a25−a24) + K24
It becomes.

Next, when P27 is obtained from P23 and P26,
C27 = (C26-C23) * (L1-L23) / (L26-L23) + C23
M27 = (M26−M23) * (L1−L23) / (L26−L23) + M23
Y27 = (Y26−Y23) * (L1−L23) / (L26−L23) + Y23
K27 = (K26−K23) * (L1−L23) / (L26−L23) + K23
It becomes. Then, (C27, M27, Y27, K27) obtained in the above procedure is the estimated device color (C2, M2, Y2, K2).

  Next, details of processing for outputting a job using the spot color correction table generated in the network system having the above-described configuration will be described. FIG. 11 is a flowchart for explaining a processing procedure for outputting a job using the spot color correction table generated in the network system having the configuration of FIGS. 1 and 2.

  First, job data is transmitted from the client 3 to the front-end server 1 through the network 4 (step S110). Here, FIG. 13 is a diagram showing an internal configuration of job data used in the network system according to the present embodiment. That is, as shown in FIG. 13, the job data according to the present embodiment includes job ticket data 131 in which contents for instructing processing to a job are described, and actual data such as PDF, PS, TIFF, and JPEG. This is a job data file 132.

  FIG. 14 is a diagram showing a detailed configuration of the job ticket data 131 shown in FIG. As shown in FIG. 14, the job ticket data 131 includes layout information 141 and color management information 142. The layout information 141 includes paper size setting information, paper type information, page orientation information, and the like. The color management information 142 includes RGB and CMYK source profiles, printer profiles, calibration setting information, and the like.

  After job data is transmitted from the client 3 to the front-end server 1 in step S110, only the job ticket data 131 in the job data is extracted (step S111). Next, the job ticket data 131 is analyzed by the job analysis unit 11B (step S112). Then, the paper type information to be output in the job ticket data 131 shown in FIG. 14 is set in Info_media (step S113).

  Next, the PDL interpreter unit 12 analyzes the job file data to generate intermediate data (step S114). Then, the intermediate data generated in step S114 is stored in the intermediate data storage unit 13 (step S115). Further, the calibration setting information is extracted from the color management information shown in FIG. 14, and it is determined whether or not the correction by the spot color correction table is performed (step S116).

  As a result, when spot color correction is not performed (No), the color management processing unit 18 performs color processing on the RGB and CMYK data according to a normal procedure for the intermediate data stored in the intermediate data storage unit 13. Matching and calibration processing is executed (step S117), and the process proceeds to step S119. On the other hand, when correction by the spot color correction table is performed in step S116 (Yes), the color matching processing unit 18 performs processing by the spot color correction table on the intermediate data stored in the intermediate data storage unit 13 (step S116). S118), the process proceeds to step 119.

  Here, details of the correction processing using the spot color correction table performed in step S118 will be described. FIG. 12 is a flowchart for explaining details of the correction process (step S118) using the spot color correction table in the flowchart of FIG.

  First, the color number of the target color is input (step S118a). Next, a target color (L1, a1, b1) corresponding to the input color number is obtained from the spot color source profile (step S118b). Next, a device-dependent device color corresponding to the target color (L1, a1, b1) is obtained from the initial printer profile stored in the profile storage unit 18A. The result is (C1, M1, Y1, K1). Further, based on the spot color correction table stored in the spot color correction table storage unit 21A, the difference value (C2-C1, M2-M1, Y2) between the device color at the time of creating the initial printer profile and the device color in the current state. -Y1, K2-K1) is obtained (step S118c).

  Next, the difference values obtained in step S118c for the eight points P11 to P18 described above surrounding the target color (L1, a1, b1) on the Lab color space on the grid of the three-dimensional lookup table of the initial profile. (C2-C1, M2-M1, Y2-Y1, K2-K1) are added (step S118d). Then, color matching is performed in the color management processing unit 18 (step S118e). Thereafter, the process proceeds to step S119.

  Thus, by using the spot color correction table, it can be applied to the target job only when it is desired to apply the spot color correction, and the original printer profile is not changed.

  In step S119, the rendering unit 14 develops the intermediate data corrected in step S117 or step S118 into bitmap image data. Then, the developed bitmap image data is transferred to the printer engine 2 (step S120). Thereafter, a sheet is selected based on the Info_media information (step S121). Then, printing is performed on the selected paper (step S122), and this process is terminated.

  The time required for the spot color correction process can be shortened by adopting the above-described configuration in which the analysis and storage processing in steps S114 and S115 and the processing in steps S118a to S118d are performed in parallel.

<Other embodiments>
In the above-described embodiment, a color sensor (RGB) is exemplified as an output patch reading unit. However, a colorimeter capable of measuring chromaticity can be used instead.

  In the above-described embodiment, processing by one site is cited. However, by using a colorimeter that automatically measures colors such as a color sensor, a plurality of networks connected by a large-scale network such as a WAN is used. It is also possible to perform remote processing on a network composed of sites.

  Furthermore, in the above embodiment, the target color is specified by the color number of the color chart. However, the target color can be extended to a spot color correction table using device-independent color values as indexes.

  Although the embodiment has been described in detail above, the present invention can take an embodiment as, for example, a system, apparatus, method, program, or storage medium (recording medium). The present invention may be applied to a system composed of a single device or an apparatus composed of a single device.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in the figure) that realizes the functions of the above-described embodiment is directly or remotely supplied to the system or apparatus, and the computer of the system or apparatus Is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  As a recording medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on the instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.

  Furthermore, after the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

1 is a configuration diagram of a network system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating detailed configurations of a front-end server 1 and a printer engine 2 illustrated in FIG. 1. It is a schematic diagram for demonstrating the flow of a process of the image data in the network system which concerns on this embodiment. It is a figure which shows an example of the spot color correction table about a certain color chart used in the network system which concerns on this embodiment. It is a schematic diagram of the Lab color space which fluctuates in the network system according to the present embodiment. It is a figure which shows an example of UI screen displayed when spot correction is started in step S90. It is a figure which shows an example of UI screen displayed when selecting the number of the color chart to perform spot correction in step S90. It is a figure showing an example of 1 composition of color sensor 26 used with a network system concerning this embodiment. 3 is a flowchart for explaining a procedure for generating a spot color correction table in a network system having the configuration of FIGS. 1 and 2. FIG. 10 is a flowchart for explaining details of device-independent color patch data generation processing in step S91 shown in FIG. 9; FIG. 3 is a flowchart for explaining a processing procedure for outputting a job using a spot color correction table generated in a network system having the configuration of FIGS. 1 and 2. 12 is a flowchart for explaining details of correction processing (step S118) using the spot color correction table in the flowchart of FIG. It is a figure which shows the internal structure of the job data used with the network system which concerns on this embodiment. It is a figure which shows the detailed structure of the job ticket data 131 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front end server 2 Printer engine 3 Client 4 Network 10 Network I / F part 11 Job control part 11A Job management part 11B Job analysis part 12 PDL interpreter part 13 Intermediate data storage part 14 Rendering part 15, 23 Communication I / F part 16 Target value storage unit 17 Color patch generation unit 17A Color patch data storage unit 18 Color management processing unit 18A Profile storage unit 18B Calibration one-dimensional LUT storage unit 19 Device color patch data storage unit 20 Device color estimation unit 20A Device color storage unit 21 Spot color correction table adjustment unit 21A Spot color correction table storage unit 22, 27 Colorimetric value storage unit 24 Output unit 25 Color sensor control unit 26 Color sensor 28, 29 Internal bus

Claims (14)

An image processing method for performing spot color correction using a printer profile and outputting a color image from a printer,
A setting process for setting a target color to be corrected;
A data generation step of generating color patch data of a device-independent color according to the target color;
A conversion step of converting the color patch data into device color patch data of a printer device dependent color using the printer profile;
Generating a device color patch chart by outputting the device color patch data from the printer; and
A colorimetric process for measuring the device color patch chart;
An estimation step for estimating a device color for reproducing the target value based on a color measurement result of the device color patch chart;
And a creation step of creating a spot color correction table using the estimated value of the device color.   2. The image according to claim 1, wherein the creating step creates the spot color correction table holding a difference value between the estimated value of the device color for reproducing the target color and the printer profile. Processing method.   The image processing method according to claim 1, further comprising a correction step of performing spot color correction using the spot color correction table. And further comprising a selection step for allowing the user to select whether spot color correction is performed by rewriting the printer profile, using the spot color correction table, or re-creating the printer profile.
The image processing method according to claim 3, wherein the correction step performs spot color correction under the condition selected in the selection step. The selection step may further allow the user to select not to perform spot color correction,
5. The image processing according to claim 4, wherein the correction process performs a color matching process and a calibration process during normal output when a selection is made that spot color correction is not performed in the selection process. Method.   The data generation step calculates a predetermined index corresponding to the target color in the device-independent color space grid, and generates each data of the 8-point grid including the index in the look-up table of the printer profile as the color patch data The image processing method according to claim 1, wherein the image processing method is performed.   The estimation step estimates four first intermediate data using the target color and data of a predetermined two-point grid in the eight-point grid generated as the color patch data, and the target color and the Two second intermediate data are estimated using two first intermediate data of the four first intermediate data, and the target color and the two second intermediate data are used to estimate the device. The image processing method according to claim 6, wherein the color is estimated.   The chart generation step generates an eight-point C, M, Y, and K mixed color patch chart as the device color patch chart, according to any one of claims 1 to 7. The image processing method as described.   9. The device according to claim 1, wherein the color measurement step measures the color of the device color patch chart using any one of an RGB output color sensor, a colorimeter, and a densitometer. An image processing method described in 1. A determination step of determining whether a printer profile exists;
The image processing method according to claim 1, wherein the setting step sets the target color on condition that the printer profile exists. An image processing apparatus that performs spot color correction using a printer profile and outputs a color image from a printer,
Setting means for setting a target color to be corrected;
Data generating means for generating color patch data of a device-independent color according to the target color;
Conversion means for converting the color patch data into device color patch data of a printer device-dependent color using the printer profile;
Chart generating means for outputting the device color patch data from the printer to generate a device color patch chart;
Colorimetric means for measuring the device color patch chart;
Estimating means for estimating a device color for reproducing the target value based on a colorimetric result of the device color patch chart;
An image processing apparatus comprising: a creation unit that creates a spot color correction table using the estimated value of the device color. Perform a spot color correction using a printer profile and output a color image from the printer.
A setting procedure for setting the target color to be corrected;
A data generation procedure for generating device-independent color patch data according to the target color;
A conversion procedure for converting the color patch data into device color patch data of a printer device-dependent color using the printer profile;
A chart generation procedure for generating the device color patch chart by outputting the device color patch data from the printer;
A colorimetric procedure for measuring the device color patch chart;
An estimation procedure for estimating a device color for reproducing the target value based on a color measurement result of the device color patch chart;
And a creation procedure for creating a spot color correction table using the estimated value of the device color.   A computer-readable storage medium storing the program according to claim 12. Receive job files over the network,
It is determined whether or not to perform spot color correction by obtaining information on whether or not to perform spot color correction from the job file,
Based on the determination result, when performing spot color correction, the initial profile is subjected to spot color correction and correction processing is performed on the data obtained by developing the job file. When spot color correction is not performed, spot color correction is performed. An image processing method, wherein correction processing is performed on data obtained by developing the job file using a non-initial profile.

Images