JP5539035B2 - Profile adjustment apparatus, profile adjustment method and program - Google Patents

Description

  The present invention relates to an apparatus, method, and program for generating / adjusting a profile used for color matching of a color printing apparatus.

  In recent years, the image quality of color printers using electrophotographic technology and inkjet technology has improved to a level comparable to that of offset printing machines. Furthermore, high-end, high-end printers can be used for printing applications such as small number of copies and proofing before actual printing by improving printing speed and supporting software for printing workflow. It has become to. Of course, in such a field, the demands on print quality, especially color, are severe.

  In a print workflow, a color matching system (CMS) using an ICC profile is conventionally used in many cases, but the purpose of CMS there is roughly divided into two. One is to achieve the same color as the offset printer by using the offset printer profile as the source profile and the printer profile as the destination profile. The other is to generate a destination profile each time and perform color matching (to stabilize the output color) in order to absorb changes with time in printer characteristics and individual differences between machines.

  If the change in printer characteristics over time is negligibly small and the colors are in good condition, once the source profile and destination profile are generated, the print workflow can proceed smoothly. it can. However, in reality, the change in the printer characteristics with time is not so small as to be negligible, and even in the field where the demand for the color is particularly severe, there are many cases where a slight variation in the color is not allowed. Therefore, a profile is frequently generated according to the changed printer characteristic state.

  To generate a profile, first, an image (patch image) including patches of many colors (usually about 1000 colors) is output by a printer. A procedure for measuring a patch on the output patch image with a spectrocolorimeter to obtain information on a color value (colorimetric value) and generating a conversion rule between a device dependent color space and a device independent color space Step on. For example, RGB or CMYK is used as the device dependent color space, and L * a * b * (hereinafter simply referred to as “Lab”) is used as the device independent color space. As described above, since the number of data of the measured color values is as large as about 1000 colors, there is a problem that it takes a lot of time for patch measurement and profile generation calculation.

  As a technique to deal with such a problem, Patent Document 1 discloses that a patch image obtained by extracting a small amount of data from a generated profile is printed and the profile is looked up based on the colorimetric data. A technique for adjusting a table (LUT) is disclosed. The invention of Patent Document 1 can shorten the time required for patch measurement and profile adjustment, so that profile adjustment according to the state of the printer can be performed with high frequency.

JP 2006-165864 A

  However, in the invention of Patent Document 1, there remains a possibility that sufficient accuracy cannot be ensured during profile adjustment.

  The characteristics of the printer vary depending on various factors in addition to the change with time. For example, in an electrophotographic printer, the image formation of a patch may affect the image formation of a patch. The electrophotographic method is a technique in which a laser beam is irradiated onto a charged photosensitive drum and an image is formed as a potential difference on the photosensitive drum. For this reason, overshoot or undershoot may occur when the laser is turned ON / OFF, and the non-uniformity of the toner image that occurs when the photosensitive drum and the toner development come into contact with each other may vary depending on the state of the adjacent color. . Furthermore, due to factors such as uneven charging due to material non-uniformity of the photosensitive drum and the distance between the laser and the photosensitive drum slightly different on the left and right on the surface of the photosensitive drum, even if an image is formed in the same color, it is reproduced depending on the location. There may also be a problem of so-called in-plane unevenness in which different colors are produced.

  When such printer characteristic variations occur, even if a patch of the same color as the patch printed at the time of profile generation is printed at the time of profile adjustment, the same color is not formed on the paper medium. The same color value may not be obtained. As a result, unnecessary adjustments may be made, or the degree of adjustment may be wrong, resulting in a problem that accurate adjustments cannot be made.

  The profile adjustment device according to the present invention includes an adjustment patch generation unit that generates adjustment patch image data in which a smaller number of adjustment patches than the number of patches in the patch image data used at the time of profile generation are arranged, and the adjustment Colorimetric means for measuring the color of each adjustment patch on the adjustment patch image output from the image forming apparatus according to the patch image data to obtain a colorimetric value, and the obtained colorimetric value and the signal of each adjustment patch Profile adjustment calculation means for adjusting a profile based on the value, and the adjustment patch creating means uses each adjustment patch as a signal value of the adjustment patch among the patches in the patch image data used at the time of profile generation. The patch image data for adjustment is created by placing it at the same position as the patch having the signal value that minimizes the difference between To.

  According to the present invention, consistency is ensured between the patch image formation conditions at the time of profile generation and the patch image formation conditions at the time of profile adjustment, so that a highly accurate profile can be easily obtained.

1 is a diagram illustrating an example of a configuration of a color printing system according to Embodiment 1. FIG. It is an external view according to type of a spectrocolorimeter. FIG. 6 is a block diagram showing a flow of processing from when the MFP receives print data to perform a print processing operation. It is a figure which shows the software module structure of a profile production | generation / adjustment apparatus. It is a figure which shows an example of the user interface screen displayed at the time of starting of a profile production / adjustment apparatus. It is a figure which shows an example of a profile production | generation time setting screen (Build setting screen). It is a figure which shows an example of patch image data. It is a figure which shows the data structure of a profile. It is a figure which shows an example of a structure of a colorimetric data file. It is a block diagram which shows the processing flow of profile generation in a profile generation calculation module. It is a figure which shows an example of the setting screen at the time of profile adjustment (Calibration setting screen). It is a flowchart which shows the detail of the preparation process of the patch image data for adjustment in the patch preparation module for profile adjustment. It is the figure which showed typically a mode that the CMYK value data for profile adjustment were extracted. It is a figure which shows an example of the patch image data for adjustment. It is a block diagram of the processing flow in a profile adjustment calculation module. 10 is an example of a screen that prompts the user to perform color measurement of a specific color according to the second embodiment. It is the figure which showed typically a mode that the CMYK value data for profile adjustment which concern on Embodiment 2 were extracted. 14 is a flowchart showing a flow of processing for creating an adjustment patch image with a separator bar added by the profile adjustment patch creation module according to the third embodiment. 15 is a flowchart showing a flow of processing for creating adjustment patch image data in a profile adjustment patch creation module according to a fourth embodiment. It is a figure which shows an example of the patch image data concerning Embodiment 3.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 is a diagram illustrating an example of a configuration of a color printing system according to the present embodiment.

  The color printing system is composed of two main components, a host PC 100 and an MFP (Multi Function Peripheral) 110, and they are connected via a network 130.

  The host PC 100 is a host computer that performs processing for generating and adjusting a profile, and is connected with a spectrocolorimeter 120.

  The host PC 100 includes an HDD 101, a ROM 102, a RAM 103, a USB I / F 104, a CPU 105, a mouse / keyboard 106, a display 107, a network I / F 108, and an internal bus 109.

  The HDD 101 is a storage device that stores programs and data.

  The ROM 102 is a memory for storing a program when the host PC 100 is activated.

  The RAM 103 is a memory that stores a program read from the HDD 101 or the ROM 102 and temporarily stores data when the program is executed.

  The USB I / F 104 performs an interface for connection with an external device.

  The CPU 105 is a processor for controlling various units by executing various programs.

  The mouse / keyboard 106 is input means for receiving input from the user.

  A display 107 is a display unit that displays input information, processing results, and the like.

  The network I / F 108 performs an interface operation with the network 130.

  The internal bus 109 is a bus that connects the above-described units.

  The spectrocolorimeter 120 is connected to the host PC 100 via the USB I / F 104 and measures a color value according to a predetermined command communication from the host PC 100.

  The MFP 110 performs print processing according to the print instruction and print data from the host PC 100 received via the network 130.

  The MFP 110 includes an HDD 111, a ROM 112, a RAM 113, a network I / F 114, an image processing unit 115, a display + touch panel 116, a CPU 117, a printer unit 118, and an internal bus 119.

  The HDD 111 is a storage device that stores programs and data.

  The ROM 112 is a memory for storing a program when the MFP 110 is activated.

  The RAM 113 is a memory that stores a program read from the HDD 111 or the ROM 112 and temporarily stores data when the program is executed.

  The network I / F 114 performs an interface operation with the network 130.

  The image processing unit 115 converts the print data received via the network I / F 114 into an image suitable for print processing in the printer unit 118.

  The display + touch panel 116 has a function of a display unit for displaying statuses of input information, processing results, and the like, and a function of an input unit that receives an input from a user.

  The CPU 117 is a processor for executing various programs and controlling each unit.

  The printer unit 118 prints an image on a recording medium (paper) based on the CMYK data converted by the image processing unit 115. Examples of the recording method of the printer unit 118 include an electrophotographic method and an ink jet method.

  The internal bus 119 is a bus that connects the above-described units.

  Next, the spectrocolorimeter 120 will be described in detail. There are a plurality of types of the spectrocolorimeter 120, and any type of spectrocolorimeter described below can be applied to the present invention.

  2A to 2D show the appearance of the spectrocolorimeter 120 by type.

  FIG. 2A shows a manual slide type spectrocolorimeter. The manual slide type spectrocolorimeter is a type that measures the color value by sliding the measurement head 201 along a measurement guide 203 placed on the object to be measured. The measurement guide 203 has a hollow portion, and has a structure that is thick enough to be in close contact with the object to be measured when the measurement hole 202 is fitted into the hollow portion. The hollow portion has a height corresponding to the measurement hole 202 of the measurement head 201 and a width of about the paper size. While the user manually slides the spectrometer, the spectral reflectance of the object to be measured is measured, converted into a Lab value, and the colorimetric value is transmitted to the host PC 100 via the USB I / F. . This is suitable when the patches to be measured are arranged continuously.

  FIG. 2B shows another embodiment of the manual spectroscopic instrument. The measurement guide 204 has the same size as the measurement hole 202 and is suitable for measuring one patch.

  FIG. 2C shows a sheet-through type spectrocolorimeter. The sheet-through spectrocolorimeter 211 includes a measurement head (not shown) inside. The spectrocolorimeter 211 sequentially conveys the object to be measured inserted in the arrow direction from the measurement slit 212 by the user, measures the spectral reflectance with an internal measurement head, converts it to a Lab value, and converts it to the host PC 100. Send colorimetric values to.

  FIG. 2D shows a table type spectrocolorimeter. The table-type spectrocolorimeter 221 includes a measurement head 224, a measurement arm 222, and a measurement table 223. The measurement head 224 is attached to the measurement arm 222 and measures an arbitrary place of the measurement object fixed on the measurement table 223 by the movement of the measurement arm 222 under the control of the host PC 100. Then, the measured spectral reflectance is sequentially converted into a Lab value, and the colorimetric value is transmitted to the host PC 100.

  Next, a processing flow until the MFP 110 receives print data and performs a print processing operation will be described with reference to the block diagram of FIG.

  This process is realized by the CPU 117 executing a program read from the HDD 111 to the RAM 113.

  First, the CPU 117 of the MFP 110 receives print data (PDL data) from the host PC 100 via the network I / F 114 and stores it in the RAM 113 (301).

  Next, the stored PDL data is interpreted (302). The PDL data has color values such as RGB values and CMYK values for each drawing data. Therefore, CMS processing for reproducing the color value by the printer is performed (303). The CMS process combines the source profile (306) indicating the color information of the monitor or offset printing press and the destination profile (307) indicating the color information of the printer to reproduce the color of the monitor or printing press on the printer. Generate color information for. The profile generated and adjusted by the host PC 100 is transferred to the HDD 111 of the MFP 110 and used as a destination profile for CMS processing.

  After finishing the CMS process, a rasterizing process is performed (304). That is, the PMS data subjected to the CMS process is developed into a bitmap in an image that matches the resolution of the printer unit 118. Then, the CPU 117 sends the developed bitmap data to the image processing unit 115.

  The image processing unit 115 performs image processing suitable for the printer unit 116, and then transfers the image to the printer unit 118 (305).

  Next, the software module configuration of the profile generation / adjustment apparatus realized as a program that runs on the host PC 100 will be described with reference to FIG.

  The software module includes three main control modules: an integrated control module 400, a profile generation control module 401, and a profile adjustment control module 406.

  First, the integrated control module 400 will be described. The integrated control module 400 causes the UI control module 405 to display a user interface screen 500 as shown in FIG. When the user presses the “Build” button 501, the profile generation control module 401 is instructed to generate a profile, and when the “Calibration” button 502 is pressed, the profile adjustment control module 406 is instructed to adjust the profile. Note that the UI control module 405 also performs interface processing with the user in response to a screen display or user input management request from the profile generation control module 401 and the profile adjustment control module 406.

  Next, the profile generation control module 401 will be described. The profile generation control module 401 is responsible for all of the profile generation processing, and controls the profile generation patch generation module 402, the patch output control module 410, the spectrocolorimeter control I / F 411, and the profile generation calculation module 403.

  The profile creation patch creation module 402 creates patch image data for profile creation based on the type information of the spectrocolorimeter 120. The created patch image data is sent to the profile generation control module 401, and is sent to the patch output control module 410 via the profile generation control module 401.

  The patch output control module 410 sends the patch image data received from the profile generation control module 401 to the MFP 110 together with a print instruction to output without performing CMS processing. MFP 110 outputs patch image data based on the received print instruction. The measurement of the patch on the patch image output from the MFP 110 is controlled via the spectrocolorimeter control I / F 411. The obtained colorimetric value is sent to the profile generation control module 401.

  The profile generation calculation module 403 includes a patch signal value (CMYK value) in patch image data, a colorimetric value (Lab value) obtained by measuring a patch on the patch image, and a parameter for profile generation as a profile generation control module. 401. Then, a profile is generated based on the received CMYK value, Lab value, and parameters, and the generated profile is sent to the profile generation control module 401. The parameters for profile generation will be described later.

  Next, the profile adjustment control module 406 will be described. The profile adjustment control module 406 is responsible for overall profile adjustment processing. For this purpose, the profile adjustment patch creation module 407, patch output control module 410, spectral colorimeter control I / F 411, colorimetric value correction module 408, and profile adjustment calculation module 409 are controlled.

  Based on the profile received from the profile adjustment control module 406 and the type information of the spectrocolorimeter 120, the profile adjustment patch creation module 407 is referred to as profile adjustment patch image data (hereinafter simply referred to as “adjustment patch image data”). .) The created patch image data for adjustment is sent to the patch output control module 410 via the profile adjustment control module 406.

  The patch output control module 410 sends adjustment patch image data to the MFP 110 together with a print instruction similar to that at the time of profile generation. The MFP 110 outputs adjustment patch image data based on the received print instruction. Then, the measurement of the adjustment patch on the adjustment patch image is controlled via the spectrocolorimeter control I / F 411. The colorimetric value of the adjustment patch is sent to the profile adjustment control module 406.

  The colorimetric value correction module 408 receives the colorimetric value of the adjustment patch from the profile adjustment control module 406 and converts it into the colorimetric value at the time of profile generation.

  The profile adjustment calculation module 409 receives the profile, the patch signal value included in the adjustment patch image data, and the colorimetric value of the adjustment patch, and adjusts the profile based on them. The adjusted profile is sent to the profile adjustment control module 406.

  The profile generated under the profile generation control module 401 and the adjustment profile generated under the profile adjustment control module 406 are stored and stored in the HDD 101 by the profile storage unit 404. Other related data, for example, a colorimetric data file (Lab value data file obtained by measuring a patch on the patch image) corresponding to the profile, and the like are also stored and stored in the HDD 101 by the profile storage unit.

  Next, parameters for profile generation will be described.

  FIG. 6 shows an example of a profile generation setting screen (Build setting screen) that the profile generation control module 401 displays on the UI control module 405 in order to allow the user to input parameters used when generating a profile.

  The Build setting screen 600 includes fields and check boxes for inputting various setting values.

  Reference numeral 601 denotes a text field for inputting a file name for saving the generated profile, and reference numeral 602 denotes a text field for inputting a file name for saving colorimetric data. Reference numeral 603 denotes a field for designating a printer as a profile generation target.

  Reference numeral 604 denotes a check box for designating the number of grid points in the profile A2B lookup table (LUT), and reference numeral 605 denotes a check box for designating the number of grid points in the profile B2A lookup table (LUT).

  Reference numeral 606 denotes a color separation table setting for generating the B2A lookup table, and is a field for designating the maximum amount of applied toner or ink. Here, 240% is specified with respect to the theoretical upper limit (400%).

  Reference numeral 607 denotes a field for designating the inking amount, and reference numeral 608 denotes a field for designating the spectrocolorimeter type. Reference numeral 609 denotes a start button for starting a profile generation operation.

  The profile generation control module 401 receives these designations, controls each module described above, and performs processing related to profile generation. For example, the profile storage unit 404 is instructed to store the generated profile and colorimetric data with the file names specified in the text fields 601 and 602, respectively. Further, the patch output control module 410 is instructed to transmit the generated patch image data to the output destination printer specified in the field 603. Further, the profile generation calculation module 403 is instructed to generate a profile with the number of grid points specified in the check boxes 604 and 605 and to perform color separation with the parameters specified in the fields 606 and 607. Further, the spectral colorimeter control I / F 411 is notified of the type of the spectral colorimeter designated in the field 608 and instructed to perform communication for the suitable spectral colorimeter.

  Next, patch image data created by the profile creation patch creation module 402 will be described.

  FIG. 7 is a diagram illustrating an example of the created patch image data.

  The profile generation patch creation module 402 first generates the entire image frame 700 corresponding to the paper size of the printer, and arranges patches in the entire image frame 700 according to the type of the spectrocolorimeter 120 to be used. . Here, it is assumed that the number of patches arranged is CMY among CMYK, the same number of divisions, and the number of CMY divisions according to the density of K as follows.

K CMY
0 6x6x6
20 6x6x6
40 6x6x6
60 6x6x6
80 4x4x4
100 3x3x3

  When the number of divisions is 6 × 6 × 6, the signal values taken by CMY are 0, 20, 40, 60, 80, and 100 (%), and the number of combinations in CMY is 216. When the number of divisions is 4 × 4 × 4, the signal values taken by CMY are 0, 33, 66, 100 (%), and the number of combinations of CMY is 64. When the number of divisions is 3 × 3 × 3, the signal values taken by CMY are 0, 50, 100 (%), and the number of combinations of CMY is 27. Therefore, the total number of patches is 955. The increase in CMY is assumed to increase in the order of C → M → Y → K. The upper left patch 701 is CMYK = (0, 0, 0, 0), that is, a patch that prints nothing.

  Next, the data structure of the profile will be described.

  FIG. 8 shows the data structure of the profile (800), which consists of a header part (801), an A2B LUT (802), and a B2A LUT (803).

  The header part includes information such as the format version of the profile, the time stamp, and the type of device to which the profile is applied.

  The A2B LUT is a lookup table for conversion from a device-dependent color space to a device-independent color space. The A2B LUT in this embodiment is composed of four-dimensional grid points of CMYK, and is a format in which Lab data is stored on each grid point.

  The B2A LUT is a lookup table for conversion from a device-independent color space to a device-dependent color space. The B2A LUT in this embodiment is a format in which CMYK data is stored on each Lab three-dimensional grid point, and color measurement (Lab value) in a device-independent color space can be measured by using what CMYK value. It expresses whether it becomes Lab value.

  In profile generation, it is necessary to generate all these pieces of information.

  The B2A LUT is a target for profile adjustment. The B2A LUT is adjusted to an optimum profile that matches the device status (printer characteristics) at that time.

  Next, the color measurement data file will be described.

  FIG. 9 shows a specific configuration of the colorimetric data file. The colorimetric data file 900 includes information such as the file name, the name of the target printer, the model number of the spectral colorimeter used, the patch number, and the Lab colorimetric value corresponding to the patch number.

  Next, a profile generation processing flow in the profile generation calculation module 403 will be described.

  FIG. 10A is a block diagram showing a processing flow for generating an A2B LUT of a profile. The profile generation calculation module 403 generates an A2B LUT by interpolation calculation processing 1001. That is, using the CMYK → Lab colorimetric value table 1002 which is a correspondence table between patch signal values (CMYK values) included in patch image data and Lab colorimetric values, Lab values for CMYK grid point values are calculated. , A2B LUT is generated. More specific description will be given below.

  Here, the grid point value of CMYK is the value of the number of grid points (17 × 17 × 17 × 17 or 9 × 9 × 9 × 9) set in the check box 604 of the Build setting screen 600 described above. That is, when the number of CMYK lattice points is 17 × 17 × 17 × 17, the CMYK values take values that increment from 0 to 100% in increments of 6.25% in the order of C → M → Y → K. Further, when the number of CMYK grid points is 9 × 9 × 9 × 9, the CMYK value takes a value that increases from 0 to 100% in increments of 12.5% in the ascending order of C → M → Y → K.

  The profile generation calculation module 403 selects several CMYK values close to each CMYK grid point value, performs an interpolation calculation 1001 using Lab values corresponding to them, and obtains Lab values corresponding to the CMYK grid point values. To go. Note that various known methods such as a linear interpolation method can be applied to the interpolation calculation 1001.

  FIG. 10 b) is a block diagram showing a processing flow for generating a profile B2A LUT. The profile generation calculation module 403 generates a B2A LUT by gamut mapping processing (Gamut Mapping) 1003, Lab → DeviceRGB conversion processing 1004, and color separation processing 1005. The Lab grid point value is the value of the number of grid points (17 × 17 × 17 or 3 × 3 × 3) set in the check box 605 of the Build setting screen 600 described above. That is, when the number of Lab grid points is 17 × 17 × 17, the value of L is incremented from 0 to 100 in 6.25 increments, and the values of a and b are incremented from −128 to 128 in increments of 16 and b → a → Generate in ascending order in the order of L. When the number of grid points is 33x33x33, the value of L is incremented in increments of 3.125 from 0 to 100, the values of a and b are incremented in increments of 8 from -128 to 128, and ascending in the order of b → a → L To generate.

  First, since the Lab value taken by the Lab grid point value is wider than the color reproduction area of the printer, color space compression is performed by gamut mapping processing. In the gamut mapping process 1003, the generated Lab grid point values are color space compressed using information in the DeviceRGB → Lab colorimetric value table 1006.

  Here, the DeviceRGB → Lab colorimetric value table 1006 is a three-dimensional LUT that takes DeviceRGB values as input and outputs Lab values, and is information that determines the reproducible range of the printer. After the process of generating the profile A2B LUT is completed, the process of obtaining the DeviceRGB → Lab colorimetric value table is performed prior to the process of generating the B2A LUT.

  FIG. 10C is a block diagram illustrating a processing flow for obtaining the DeviceRGB → Lab colorimetric value table 1006.

  First, DeviceRGB grid point values are generated. Assuming that the number of grid points is 33 × 33 × 33, for example, DeviceRGB grid point values are incremented in increments of 8 from 0 to 255, and are generated in ascending order from B → G → R. The color separation processing 1005 performs color separation of the generated DeviceRGB values into CMYK values based on the information on the maximum toner / ink application amount 606 and the inking amount 607 on the Build setting screen 600 described above. Thereafter, the same interpolation operation 1001 as that used in the above-described A2B LUT generation flow is performed to obtain the Lab value. In this way, the DeviceRGB → Lab colorimetric value table 1006 is obtained.

  Returning to the description of the processing flow for generating the B2A LUT.

  In a Lab → DeviceRGB conversion process 1004 subsequent to the gamut mapping process 1003, the Lab space-compressed Lab value is inversely converted into a DeviceRGB value using the DeviceRGB → Lab colorimetric value table 1006 obtained as described above. There are various known methods for the inverse transformation operation, and any method may be used.

  Finally, the color separation processing 1005 performs color separation from DeviceRGB values to CMYK values based on given parameters (information on the maximum toner / ink application amount 606 and inking amount 607 set on the Build setting screen 600). I do.

  By these processes, CMYK values corresponding to the Lab grid point values are calculated, and the B2A LUT is completed.

  As described above, the profile generation control module 401 generates the profile by obtaining the A2B LUT and the B2A LUT. The generated profile is stored in the profile storage unit 404.

  Next, profile adjustment processing in the profile adjustment control module 406 will be described.

  FIG. 11 shows an example of a profile adjustment setting screen (Calibration setting screen) displayed on the UI control module 405 when the profile adjustment control module 406 starts the profile adjustment processing.

  Similar to the Build setting screen 600, the calibration setting screen 1100 includes fields for inputting various setting values.

  Reference numeral 1101 denotes a field for designating the file name of the profile to be adjusted, and 1102 denotes a field for designating the file name of the colorimetric data file when the profile is generated.

  Reference numeral 1103 denotes a field for designating a target printer, and reference numeral 1104 denotes a drop-down list for designating a spectrocolorimeter type. Reference numeral 1105 denotes a start button for starting profile adjustment processing.

  When such information is input by the user and the start button 1105 is pressed, the profile adjustment control module 406 receives the information input by the user from the UI control module 405 and controls each module as follows.

  First, the profile adjustment control module 406 passes the profile and the type information of the spectrocolorimeter 120 to the profile adjustment patch creation module 407 and instructs the creation of adjustment patch image data. When the adjustment patch image data is created, the profile adjustment control module 406 sends the adjustment patch image data to the patch output control module 410 and instructs it to be output by the target printer. When the adjustment patch image is output from the target printer and the user is ready to measure the patch on the adjustment patch image, the colorimetric value is acquired via the spectrocolorimeter control I / F 411. Then, the profile adjustment control module 406 sends the signal value and colorimetric value of the adjustment patch to the profile adjustment calculation module 409, and instructs execution of adjustment of the B2A LUT of the profile.

  Hereinafter, processing of the profile adjustment patch creation module 407 and the profile adjustment calculation module 409 will be described in detail.

  First, the processing of the profile adjustment patch creation module 407 will be described.

  FIG. 12 is a flowchart showing details of adjustment patch image data creation processing in the profile adjustment patch creation module 407.

  In step 1200, the profile adjustment patch creation module 407 receives the adjustment patch image data creation instruction from the profile adjustment control module 406 and starts processing.

  In step 1201, the profile adjustment patch creation module 407 appropriately samples Lab grid point values from the B2A LUT of the profile at the time of generation, and extracts CMYK values corresponding to the sampled Lab grid point values. FIG. 13 is a diagram schematically illustrating how the corresponding CMYK values are extracted. For convenience of explanation, 1300 shows Lab grid points of the B2A LUT that are two-dimensionally shown with a reduced number of grid points, and 1301 shows the boundary of the color reproduction area of the printer. The Lab grid points are evenly sampled so as to obtain a predetermined number of patches from the Lab grid point values inside or near the printer color gamut boundary 1301, and the corresponding CMYK values 1302 are extracted. The predetermined number of patches can be arbitrarily determined by the user, and is about 100 points, for example. If FIG. 13 shows the state of sampling when obtaining about 100 patches, the sampling density is halved when obtaining 50 patches, and sampling when obtaining 200 patches. The density of will be doubled.

  In step 1202, the profile adjustment patch creation module 407 obtains the difference between the extracted corresponding CMYK values and the patch CMYK values in the patch image data used at the time of profile generation. Then, the CMYK value of the patch at the time of generating the profile with the smallest absolute value of the difference is extracted.

  In step 1203, the profile adjustment patch creation module 407 obtains the coordinate position in the patch image data of the extracted “CMYK value of the patch when generating the profile with the smallest absolute value of difference”.

  In step 1204, the profile adjustment patch creation module 407 places a patch (adjustment patch) having a corresponding CMYK value at the same coordinate position as the obtained coordinate position.

  In step 1205, the profile adjustment patch creation module 407 arranges surrounding patches in the patch image data at the time of profile generation around the adjustment patch. That is, the patch in the patch image data at the time of profile generation located near the periphery 8 of the coordinate position obtained in step 1203 is disposed at the coordinate position near the periphery 8 of the adjustment patch disposed in step 1204.

  In step 1206, the profile adjustment patch creation module 407 determines whether the processing in steps 1202 to 1205 has been completed for all the corresponding CMYK values extracted in step 1201 and the arrangement of all adjustment patches has been determined. If processing has been completed for all the extracted corresponding CMYK values, the process proceeds to step 1207. If the processing has not been completed for all the corresponding CMYK values, the process returns to step 1202, and the processing of steps 1202 to 1205 is repeated for the unprocessed corresponding CMYK values.

  In step 1207, the profile adjustment patch creation module 407 creates adjustment patch image data in which all the adjustment patches (including patches in the vicinity of the surrounding 8) are arranged according to the determined arrangement.

  In this way, the profile adjustment patch creation module 407 appropriately arranges the extracted corresponding CMYK values, and creates adjustment patch image data suitable for the paper size suitable for the printer and the type of spectrocolorimeter. .

  FIG. 14 is a diagram illustrating an example of adjustment patch image data created as described above. Reference numeral 1400 denotes a frame of adjustment patch image data corresponding to the paper size of the printer. An adjustment patch 1401 composed of corresponding CMYK values extracted for profile adjustment is arranged in a frame 1400. The position of the adjustment patch 1401 is CMYK = (20, 40, 0, 0)% in the patch image data when the original profile is generated, whereas CMYK = (25, 38, 5, 2). It has become. Eight patches (patches located in the vicinity of CMYK = (20, 40, 0, 0) around 8 in the patch image data at the time of profile generation) 1402 are arranged so as to surround the periphery of the adjustment patch 1401. ing. Although omitted here, the remaining adjustment patches are also arranged in the same manner as the adjustment patch 1401.

  The adjustment patch image data created in this way is sent to the profile adjustment control module 406.

  When measuring a patch on the adjustment patch image with the spectrocolorimeter, it is sufficient to measure only the position of the adjustment patch arranged as described above (that is, for the patches in the vicinity of the surrounding 8). Do not measure colors.) Therefore, the profile adjustment control module 406 instructs the spectrocolorimeter control I / F 411 to measure only the position of the adjustment patch when the spectrocolorimeter to be used is a table type or a sheet-through type. To do. On the other hand, when the spectrocolorimeter to be used is a manual type, it is only necessary to measure only the position of the adjustment patch using a measurement guide 204 that is not a slide type.

  Next, processing of the profile adjustment calculation module 409 will be described.

  FIG. 15 is a block diagram of a processing flow in the profile adjustment calculation module 409.

  First, the profile adjustment calculation module 409 performs a differential Lab calculation process 1501. Specifically, the difference between the Lab grid point value sampled in step 1201 of FIG. 12 described above and the adjustment patch colorimetric value Lab1502 that is a value obtained by measuring the adjustment patch on the adjustment patch image is calculated. To do. Since the adjustment patch image is a CMYK value that reproduces the Lab lattice point value Lab, if the printer characteristics have not changed, the difference is zero at each Lab lattice point. On the other hand, if the characteristics of the printer fluctuate, a difference (difference Lab value) for each Lab lattice point is obtained.

  Next, the profile adjustment calculation module 409 performs a differential Lab value propagation process 1503. Specifically, a process of propagating the differential Lab value obtained by the above calculation to each lattice point of the B2A LUT is performed. That is, an interpolation operation is performed so that the obtained difference Lab value is smoothed to each grid point. As a result, the Lab value of each lattice point of the B2A LUT varies according to the variation of the printer characteristics.

  Finally, the profile adjustment calculation module 409 performs an interpolation calculation process 1504 to obtain an adjusted B2A LUT. Specifically, the CMYK value corresponding to the changed Lab value is obtained by interpolation using the B2A LUT 1505 of the original profile, and a B2A LUT (Lab → CMYK conversion look-up table) suitable for the printer with the changed characteristics is obtained. .

  As described above, according to the present invention, patches having substantially the same signal value (CMYK value) configuration are printed at the same position during profile generation and profile adjustment. Thereby, the influence of the above-mentioned in-plane nonuniformity can be prevented. It should be noted that the “same position” here does not refer to only the same position, but it is a concept including substantially the same position with a slight shift in consideration of the influence of unevenness in the image. No. In addition, the effect of patches located around the patch to be measured can be made similar between the time of profile generation and the time of profile adjustment, and the printer for the colorimetric values of the adjustment patch on the adjustment patch image The influence of fluctuation factors can be minimized.

[Embodiment 2]
In the first embodiment, for example, an adjustment patch image in which the number of adjustment patches is about 100 points is obtained, and the profile is adjusted efficiently and accurately over the entire color reproduction range of the printer. Next, an embodiment in which a profile is adjusted only for a specific color according to occasional needs will be described as a second embodiment. Note that description of parts common to the flowchart of FIG. 12 according to the first embodiment is simplified or omitted, and here, differences will be mainly described.

  In this embodiment, the profile adjustment control module 406 instructs the UI control module 405 to display a screen as shown in FIG. 16, for example, before operating the profile adjustment patch creation module 407. In accordance with such display, the user measures the color of an adjustment patch image on which a patch of a specific color to be adjusted is printed using a manual spectrocolorimeter as shown in FIG.

  Then, in response to the user pressing the OK button, the profile adjustment control module 406 acquires the Lab value via the spectrocolorimeter control I / F 411. The acquired Lab value is sent to the profile adjustment patch creation module 407.

  The profile adjustment patch creation module 407 applies the received Lab value as a measured Lab value to a Lab lattice point on the B2A LUT, and extracts a Lab lattice point in the vicinity of the measured Lab value. Then, CMYK values corresponding to the extracted Lab lattice points are acquired.

  FIG. 17 is a schematic diagram showing how neighboring Lab grid points are extracted from the received Lab values and the corresponding CMYK values are acquired. The received Lab value is applied to the Lab lattice point 1700 on the B2A LUT as the measured Lab value 1701 to extract the neighboring Lab lattice point, and the CMYK value 1702 corresponding to the Lab lattice point is obtained.

  Thereafter, adjustment patch image data is created by the same processing as that shown in FIG. 12 of the first embodiment. That is, the profile adjustment patch creation module 407 performs the processing from step 1202 onward in FIG. 12 to create adjustment patch image data in which only specific adjustment patches are arranged.

  Thus, the user can adjust the profile only for a desired specific color, and can perform more efficient profile adjustment.

[Embodiment 3]
In the manual slide type spectrocolorimeter, the colorimetric position continuously moves according to the manual slide. Therefore, the boundary between patches cannot be recognized unless there is a color difference between the patches. Therefore, a mark (separator bar) that separates the boundaries between patches is essential. When providing a separation bar, a dark separation bar is added if two adjacent colors are light at the separation position of the color to be measured, and a light separation bar is added if both adjacent colors are dark. In addition, it is common to indicate the separation between patches.

  Accordingly, when a manual slide type spectrocolorimeter is used for colorimetry of patches on the patch image data at the time of generating a profile, for example, patch image data as shown in FIG. In FIG. 20A, 2000 is a patch, 2001 is a delimiter bar (for example, composed of white pixels) for indicating a boundary of a dark color patch, and 2002 is a delimiter for indicating a boundary of a light color patch. Bar (for example, composed of black pixels).

  However, the same type of spectrocolorimeter is not always used for profile generation and adjustment. A manual slide type is used for generation, but a table type spectrocolorimeter may be used for adjustment. When a table-type spectrocolorimeter is used, the patch measurement position can be controlled via the spectrocolorimeter control I / F 411, and such a separation bar is not always necessary. However, the separator bar is also part of image formation, and it is desirable to form the adjustment patch image under the same conditions as possible when generating the profile.

  In the present embodiment, an embodiment in which a mark that delimits the boundary between patches is added to the patch image data for adjustment when a manual slide type is used at the time of profile generation and another type is used at the time of adjustment will be described as a third embodiment.

  FIG. 18 is a flowchart showing a flow of processing for creating adjustment patch image data with a separator bar added by the profile adjustment patch creation module 407. Note that description of parts common to the flowchart of FIG. 12 according to the first embodiment is simplified or omitted, and here, differences will be mainly described.

  In step 1800, the profile adjustment patch creation module 407 receives the adjustment patch image data creation instruction from the profile adjustment control module 406 and starts processing.

  In step 1801, the profile adjustment patch creation module 407 determines the type of the spectrocolorimeter. That is, it is determined whether or not the spectrocolorimeter used at the time of profile generation is a manual slide type. If the spectral colorimeter used at the time of profile generation is a manual slide type, the process proceeds to step 1802. If the spectrocolorimeter used at the time of profile generation is another type of spectrocolorimeter, the process proceeds to step 1814, and processing according to the flow of FIG. 12 according to the first embodiment is performed.

  Steps 1802 to 1805 are the same as steps 1201 to 1204 in FIG. That is, a predetermined number of adjustment patches are respectively arranged at the coordinate positions of the patches having the closest signal value among the patches in the patch image data at the time of profile generation.

  In step 1806, the profile adjustment patch creation module 407 detects the patch (adjacent to the patch identified as the patch having the closest signal value among the patches at the time of profile generation at adjacent positions on both sides of the adjustment patch. Patch) is placed.

  In step 1807, the profile adjustment patch creation module 407 calculates the difference between the adjustment patch signal value (CMYK value) and the adjacent patch signal value (CMYK value).

  In step 1808, the profile adjustment patch creation module 407 determines whether the calculated absolute value of the difference is smaller than a threshold value. Specifically, it is determined whether ΔE is smaller than 5, for example. If the absolute value of the difference is smaller than the threshold value, the process proceeds to step 1809. If the absolute value of the difference is greater than or equal to the threshold value, it is determined that there is no need to add a separator bar, and the process proceeds to step 1812.

  In step 1809, the profile adjustment patch creation module 407 determines the color density of the adjacent patch. Specifically, it is determined whether or not the CMYK value of the adjacent patch is equal to or greater than a predetermined value (for example, 50% when 100% is the maximum value of the CMYK value). If the color of the adjacent patch is light (CMYK value is less than 50%), the process proceeds to step 1810. If the color of the adjacent patch is dark (CMYK value is 50% or more), the process proceeds to step 1811.

  In step 1810, the profile adjustment patch creation module 407 inserts a separator bar composed of black pixels at the boundary between the adjacent patch and the adjustment patch.

  In step 1811, the profile adjustment patch creation module 407 inserts a separator bar composed of white pixels at the boundary between the adjacent patches and the adjustment patch.

  In step 1812, the profile adjustment patch creation module 407 determines whether the processing in steps 1808 to 1811 has been completed for all the adjustment patches. If all adjustment patches have been completed, the process proceeds to step 1813. If all adjustment patches have not been completed, the process returns to step 1808.

  In step 1813, the profile adjustment patch creation module 407 creates the adjustment patch image data with the separator bar inserted according to the above contents.

  FIG. 20B is an example of adjustment patch image data created by the method described above. It can be seen that adjacent patches 2005 are arranged on both sides of the adjustment patch 2004, and a set 2003 of them is arranged in a tooth-missing manner.

  According to this embodiment, a patch image having a separation bar for a manual slide type spectrocolorimeter can be reproduced even when a spectrocolorimeter other than the manual slide type is used during profile adjustment. Therefore, it is possible to reduce the influence on the profile adjustment that may be caused by the difference in the patch image forming conditions such as the presence or absence of the separation bar.

[Embodiment 4]
In the adjustment patch (corresponding CMYK value) extraction process in the first embodiment, Lab grid points in the printer color reproduction area 1201 are selected so that the number of patches is, for example, about 100 points, and corresponding CMYK values are extracted. It was. However, the array of extracted corresponding CMYK values is not necessarily the same as the array of patch signal values at the time of profile generation. Depending on the printer, the situation of overshoot or undershoot given to adjacent patches may change depending on the ascending / descending order of the color values. In order to prevent such a situation, when converting the extracted corresponding CMYK values into an adjustment patch image, a mode in which the corresponding CMYK values are rearranged in consideration of the arrangement rule of the patch signal values at the time of profile generation is described in the fourth embodiment. Will be described.

  FIG. 19 is a flowchart showing a flow of processing for creating adjustment patch image data in the profile adjustment patch creation module 407 according to the present embodiment. Note that description of parts common to the flowchart of FIG. 12 according to the first embodiment is simplified or omitted, and here, differences will be mainly described.

  Upon receiving the adjustment patch image data generation instruction (S1900), the profile adjustment patch generation module 407 extracts CMYK values corresponding to the sampled Lab grid point values (S1901).

  In step 1902, the profile adjustment patch creation module 407 determines whether or not the extracted corresponding CMYK values are in the same array (CMYK ascending order or CMYK descending order) as the patch signal values in the patch image data at the time of profile generation. Note that the patch image data shown in FIG. 7 is in ascending order of CMYK. If they are the same arrangement, the process proceeds to step 1904, and if they are different, the process proceeds to step 1903.

  In step 1903, the profile adjustment patch creation module 407 sorts the extracted array of corresponding CMYK values into the same array (CMYK ascending order or CMYK descending order) as the patch signal values in the patch image data at the time of profile generation.

  In step 1904, the profile adjustment patch creation module 407 calculates the difference between the corresponding CMYK values sorted as necessary and the patch CMYK values in the patch image data at the time of profile generation. Then, the CMYK value of the patch at the time of generating the profile with the smallest absolute value of the difference is extracted.

  Thereafter, patch image data for profile adjustment is created by the processes in steps 1905 to 1909 corresponding to steps 1203 to 1207 in FIG.

  According to the present embodiment, since the arrangement of patch signal values in the patch image data is always the same during profile generation and during profile adjustment, the influence on the profile adjustment due to the difference in the arrangement of patch signal values can be reduced. Can do.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

Claims (7)

A profile adjusting device for adjusting a profile of an image forming apparatus,
Adjustment patch creation means for creating adjustment patch image data in which a smaller number of adjustment patches than the number of patches in the patch image data used at the time of profile generation are arranged;
Colorimetric means for measuring the color of each adjustment patch on the adjustment patch image output from the image forming apparatus according to the adjustment patch image data to obtain a colorimetric value;
Profile adjustment calculation means for adjusting the profile based on the obtained colorimetric value and the signal value of each adjustment patch,
The adjustment patch creation means places each adjustment patch at the same position as a patch having a signal value that minimizes the difference from the signal value of the adjustment patch among the patches in the patch image data used at the time of profile generation. Arrange and create patch image data for adjustment,
A profile adjusting apparatus characterized by the above.   The adjustment patch creation means includes patches arranged around the patch having a signal value that minimizes a difference from the signal value of the adjustment patch among the patches in the patch image data used at the time of profile generation. 2. The profile adjustment device according to claim 1, wherein the profile adjustment device is arranged around each adjustment patch. A profile adjusting device for adjusting a profile of an image forming apparatus,
Adjustment patch creation means for creating adjustment patch image data in which adjustment patches of a specific color designated by the user are arranged;
Colorimetric means for measuring the color of each adjustment patch on the adjustment patch image output from the image forming apparatus according to the adjustment patch image data to obtain a colorimetric value;
Profile adjustment calculation means for adjusting the profile based on the obtained colorimetric value and the signal value of each adjustment patch,
The adjustment patch creation means is a signal value that minimizes the difference between the specific color adjustment patch and the signal value of the specific color adjustment patch among the patches in the patch image data used at the time of profile generation. Create the patch image data for adjustment by placing it at the same position as the patch with
A profile adjusting apparatus characterized by the above. A profile adjusting device for adjusting a profile of an image forming apparatus,
Adjustment patch creation means for creating adjustment patch image data in which a smaller number of adjustment patches than the number of patches in the patch image data used at the time of profile generation are arranged;
Colorimetric means for measuring the color of each adjustment patch on the adjustment patch image output from the image forming apparatus according to the adjustment patch image data to obtain a colorimetric value;
Profile adjustment calculation means for adjusting the profile based on the obtained colorimetric value and the signal value of each adjustment patch,
The adjustment patch creation means includes:
Means for determining whether the spectrocolorimeter used to measure the color of the patch on the patch image when generating the profile is a manual slide type;
When the determination means determines that the spectrocolorimeter used is a manual slide type,
Each adjustment patch is arranged at the same position as the patch having a signal value that minimizes the difference from the signal value of the adjustment patch among the patches in the patch image data used at the time of profile generation,
Of the patches in the patch image data used at the time of profile generation, a patch adjacent to the patch having a signal value that minimizes the difference from the signal value of the adjustment patch is arranged adjacent to each adjustment patch. ,
Inserting a mark that delimits the boundary between the adjustment patch arranged at the same position and the patch arranged adjacent to the adjustment patch to create adjustment patch image data;
A profile adjusting apparatus characterized by the above.   3. The profile adjustment apparatus according to claim 1, wherein the adjustment patch creation unit arranges the adjustment patches in the same arrangement as the arrangement of the patches in the patch image data used when generating the profile. A profile adjustment method for adjusting a profile of an image forming apparatus,
An adjustment patch creation step for creating adjustment patch image data in which a smaller number of adjustment patches than the number of patches in the patch image data used at the time of profile generation are arranged;
A colorimetric step for measuring each adjustment patch on the adjustment patch image output from the image forming apparatus according to the adjustment patch image data to obtain a colorimetric value;
A profile adjustment calculation step for adjusting the profile based on the obtained colorimetric value and the signal value of each adjustment patch,
In the adjustment patch creation step, each adjustment patch is placed at the same position as a patch having a signal value that minimizes the difference from the signal value of the adjustment patch among the patches in the patch image data used when generating the profile. Arrange and create patch image data for adjustment,
A profile adjustment method characterized by the above.   A program for causing a computer to execute the method according to claim 6.

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