JP2020152003A - Image formation controller, image formation control method, and image formation control program - Google Patents

Abstract

To select an image formation device exhibiting high color reproducibility by paying attention to a frequency distribution of color differences.SOLUTION: An image formation controller comprises: a first color conversion part which converts input image data to input image data for comparison that is image data of a color space for color difference comparison; a second color conversion part which acquires an output profile and a simulation profile expressing the characteristics of plural image formation devices, converts the input image data for comparison to output image data for reproducing the input image data for comparison using plural color materials, on the basis of each output profile, and converts a color space of the output image data on the basis of each simulation profile, in order to convert the output image data to each output image data for comparison that is image data of the color space for color difference comparison; a color difference calculation part for comparing a color difference between the input image data for comparison and the output image data for comparison for each pixel, and calculating a specific color difference that is a color difference arising when a cumulative relative frequency of the color difference is a predetermined ratio, for each of the plural image formation devices; and a device selection part which preferentially selects an image formation device having a small specific color difference.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming control device, an image forming control method, and an image forming control program, and particularly to a technique for selecting an image forming device having high color reproducibility.

The image forming apparatus has various reproducible color gamuts for each model. In general, a high-end image forming apparatus has a relatively wide color gamut, and a low-end image forming apparatus has a relatively narrow color gamut. In consideration of such characteristics of the image forming apparatus, for example, Patent Document 1 describes a color close to the color of the image data based on the average value of the color difference between the color gamut of the image forming apparatus and the color of the image data to be printed. We are proposing a technology that selects an image forming device that can be expressed and prints it automatically. As a result, Patent Document 1 states that it is possible to print in a color closer to the color included in the image data.

Japanese Unexamined Patent Publication No. 2008-171268

However, the inventor of the present application has found that when an image forming apparatus is selected based on the average value of color differences, the evaluation of the image forming apparatus may be separated from the evaluation based on human visual sense due to the influence of so-called singular points. .. A singular point is an isolated specific region with a large color difference in the frequency distribution of the color difference.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique for selecting an image forming apparatus having high color reproducibility by paying attention to a frequency distribution of color differences.

The present invention provides an image formation control device for selecting a specific image forming device from a plurality of image forming devices and causing the specific image forming device to perform image formation based on input image data. The image formation control device includes a first color conversion unit that converts the input image data into comparative input image data that is image data of a color space for color difference comparison for comparing color differences, and the plurality of image forming devices. An output profile and a simulation profile representing the respective characteristics of the above are acquired, and based on each acquired output profile, the comparison input image data is converted into output image data for reproducing with a plurality of color materials, and the acquisition is performed. The color space of the converted output image data based on each simulation profile is converted for each of the plurality of image forming devices and converted into each comparison output image data which is the image data of the color difference comparison color space. The color difference between the color conversion unit 2 and the comparison input image data and each comparison output image data is compared for each pixel, and a specific color difference which is a color difference when the cumulative relative frequency of the color difference becomes a predetermined ratio is obtained. It includes a color difference calculation unit that calculates for each of the plurality of image forming devices, and a device selection unit that preferentially selects the image forming device having a small specific color difference over the image forming device having a large specific color difference.

The image forming system of the present invention includes the image forming control device and the plurality of image forming devices.

The present invention provides an image formation control method for selecting a specific image forming apparatus from a plurality of image forming apparatus and causing the specific image forming apparatus to execute image formation based on input image data. The image formation control method includes a first color conversion step of converting the input image data into comparative input image data which is image data of a color space for color difference comparison for comparing color differences, and the plurality of image forming devices. An output profile and a simulation profile representing the respective characteristics of the above are acquired, and based on each acquired output profile, the comparison input image data is converted into output image data for reproducing with a plurality of color materials, and the acquisition is performed. The color space of the converted output image data based on each simulation profile is converted for each of the plurality of image forming devices and converted into each comparison output image data which is the image data of the color difference comparison color space. The color difference between the color conversion step 2 and the comparison input image data and each comparison output image data is compared for each pixel, and a specific color difference which is a color difference when the cumulative relative frequency of the color difference becomes a predetermined ratio is obtained. It includes a color difference calculation step calculated for each of the plurality of image forming devices, and a device selection step of preferentially selecting the image forming device having a small specific color difference over the image forming device having a large specific color difference.

The present invention is an image formation control program that selects a specific image forming apparatus from a plurality of image forming apparatus and controls an image forming control apparatus for executing image forming based on input image data in the specific image forming apparatus. I will provide a. The image formation control program is a first color conversion unit that converts the input image data into comparison input image data, which is image data of a color space for color difference comparison for comparing color differences, and the plurality of image forming devices. An output profile and a simulation profile representing each characteristic are acquired, and based on each acquired output profile, the comparison input image data is converted into output image data for reproducing with a plurality of color materials, and the acquired data is obtained. The second color space of the converted output image data based on each simulation profile is converted for each of the plurality of image forming devices and converted into each comparison output image data which is the image data of the color difference comparison color space. The color conversion unit of the above, the color difference between the comparison input image data and each comparison output image data is compared for each pixel, and the plurality of specific color differences which are the color differences when the cumulative relative frequency of the color difference becomes a predetermined ratio. The image formation control device is used as a device selection unit that preferentially selects the color difference calculation unit calculated for each image forming apparatus and the image forming apparatus having a small specific color difference over the image forming apparatus having a large specific color difference.

According to the present invention, it is possible to provide a technique for selecting an image forming apparatus having high color reproducibility by paying attention to the frequency distribution of color difference.

It is a schematic block diagram which shows the whole structure of the image formation system which concerns on one Embodiment of this invention. It is a flowchart which shows the content of the printing processing procedure which concerns on one Embodiment. It is a flowchart which shows the content of the monochrome device selection process which concerns on one Embodiment. It is a flowchart which shows the content of the color device selection process which concerns on one Embodiment. It is a flowchart which shows the content of the input / output color difference calculation process which concerns on one Embodiment. It is explanatory drawing which shows the content of the cumulative relative frequency of a color difference which concerns on one Embodiment. It is explanatory drawing which compares and shows the color gamut (gamut) of the input image and output image which concerns on one Embodiment.

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “embodiments”) will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an overall configuration of an image forming system 10 according to an embodiment of the present invention. The image forming system 10 includes three image forming devices 100 (100a to 100c), three personal computers 200 (200a to 200c), a server 300, and a local area network (simply also referred to as LAN) connecting these. ) 500 and. The three image forming devices 100a to 100c have different color gamuts and color reproduction characteristics.

The image forming apparatus 100 includes a control unit 110, an image forming unit 120, an image reading unit 130, a storage unit 140, and a communication interface unit 150 (also referred to as a communication I / F). The image forming unit 120 includes a color conversion processing unit 121 and a halftone processing unit 122. The image reading unit 130 reads an image from the document, generates an image data ID which is RGB image data, and transmits the image data ID to the image forming unit 120. The RGB image data is device-dependent (depending on the image reading unit 130) image data.

The image reading unit 130 has the characteristics defined in the input profile. If the input profile is used, the image data ID which is the device-dependent RGB image data can be converted into the Lab image data which is the image data of the Lab color space. As a result, the image forming apparatus 100 can convert it into, for example, sRGB image data and output it as scan data via the Lab color space.

The image forming unit 120 has the characteristics defined in the output profile. If the output profile is used, the Lab image data can be converted into CMYK image data which is image data in the CMYK color space. The characteristics of the image forming unit 120 can be simulated by the simulation profile. The simulation profile can be used to convert CMYK image data into Lab image data.

The image forming apparatus 100 has a device link profile that combines an input profile and an output profile. The device link profile can reduce the burden of the color conversion process and improve the printing speed in the copying process. The output profile and the simulation profile have an irreversible relationship. That is, when the Lab image data is converted into CMYK image data using the output profile and the CMYK image data is converted into Lab image data using the simulation profile, before and after the conversion due to the characteristics of the image forming unit 120. A color difference ΔE occurs between the Lab image data.

At the time of copying, the color conversion processing unit 121 converts RGB image data using the device link profile to generate CMYK image data. The CMYK image data is device-dependent (depending on the image forming unit 120) image data for reproducing an image with the CMYK color material available in the image forming unit 120. The image forming unit 120 executes RIP processing on the CMYK image data in the halftone processing unit 122 to generate dot data which is bitmap data. The dot data is data representing the formation state of dots formed of CMYK (ink or toner). The color material is not limited to CMYK, and may be a plurality of other color materials (for example, CMYKlclm, CMYK + Orange + Green, etc.).

The image forming unit 120 forms an image on a print medium (not shown) based on the dot data and discharges the image. In this example, it is assumed that an image is formed on a print medium (not shown) and discharged based on a print job received from the personal computer 200. The dot data is bitmap data representing a dot formation state on the print medium. The print medium is also called an image forming medium.

The personal computers 200a to 200c have the same configuration, and include a control unit 210, an operation display unit 230, and a storage unit 240. The control unit 210 has a color difference analysis unit 211 and a device selection unit 212. The operation display unit 230 has characteristics defined by a monitor profile, and is a user operation input (also referred to simply as a user input) from a display (not shown) that functions as a touch panel and various buttons and switches (not shown). Accept. The server 300 includes a control unit 310 and a storage unit 340. The storage unit 340 stores the image forming apparatus database 341.

The control units 110, 210, and 310 include main storage means such as RAM and ROM, and control means such as MPU (Micro Processing Unit) and CPU (Central Processing Unit). In addition, the control units 110, 210, and 310 include controller functions related to interfaces such as various I / O, USB (universal serial bus), bus, and other hardware, and include an image forming apparatus 100, a personal computer 200, and a personal computer 200. Controls the entire server 300.

The storage units 140, 240, and 340 are storage devices including a hard disk drive, a flash memory, and the like which are non-temporary recording media, and store image formation control programs and data executed by the control unit 110 and the like. The storage unit 240 stores an ICC profile (monitor profile) for the display of the operation display unit 230. The storage unit 340 stores the image forming apparatus database 341. The ICC profiles of the three image forming devices 100a, 100b, and 100c are registered in the image forming device database 341. Each ICC profile includes an input profile, an output profile and a simulation profile.

FIG. 2 is a flowchart showing the contents of the printing processing procedure according to the embodiment. In this printing processing procedure, an image forming apparatus (also called a device) having a small color difference with respect to the input image data and having high color reproducibility is semi-automatically selected from the three image forming apparatus 100a, 100b, 100c. , Can be printed with the selected image forming apparatus.

The user selects, for example, one of sRGB, Adobe RGB, and CMYK (Japan Color 2001 Coated, etc.) as a work color space in advance using graphic software in the personal computer 200, and a desired print target to be printed. Generate an image. In this example, it is assumed that the user selects the sRGB color space to perform the work. In this case, the personal computer 200 uses the monitor profile for the display of the operation display unit 230 to convert the sRGB image data representing the desired print target image and display it on the display (not shown).

In step S100, the control unit 210 of the personal computer 200 executes the image data acquisition process. In the image data acquisition process, the user operates graphic software to display the print setting screen on a display (not shown). On the other hand, the control unit 210 controls the graphic software to acquire the sRGB image data. The sRGB image data is device-independent color space image data.

In step S200, the user executes the print setting process. In the print setting process, the user sets the selection of color printing or monochrome printing, the number of copies to be printed, the paper type of printing paper, and the basis weight range. The control unit 210 acquires the contents set in the print setting process, and further acquires the Source profile based on the sRGB color space selected as the work color space. The control unit 210 calculates the number of prints using the number of prints and the number of pages, and estimates the amount of color material used based on the number of prints and the image content. The control unit 210 acquires the contents of the print setting as the print setting input. The print setting input is also called an image formation setting input.

In step S300, the user sets the device selection mode. As a result, the image forming system 10 semi-automatically selects a candidate of an image forming apparatus (also referred to as a device) having a small color difference with respect to the input image data and having high color reproducibility from among the three image forming apparatus 100a, 100b, 100c. It is possible to print with an image forming apparatus selected from the selected candidates.

In step S400, the control unit 210 determines whether color printing or monochrome printing is selected. The control unit 210 advances the process to step S500 when monochrome printing is selected, and proceeds to step S600 when color printing is selected. In step S500, the monochrome device selection process is executed. Note that the control unit 210 may proceed to step S500 if the content of the print setting is color printing but the content of the image is monochrome.

FIG. 3 is a flowchart showing the contents of the monochrome device selection process (step S500) according to the embodiment. In step S510, the control unit 210 executes the monochrome device extraction process. In the monochrome device extraction process, the control unit 210 of the personal computer 200 inquires the server 300 of the monochrome device via the LAN 500. The server 300 refers to the image forming apparatus database 341, extracts the monochrome device, and returns it to the personal computer 200. As a result, the control unit 210 can know the monochrome device as a print destination candidate.

In step S520, the control unit 210 narrows down (selects) a print destination candidate from the monochrome devices as print destination candidates based on the printing material. Specifically, the control unit 210 can use the paper type and basis weight range as the printing paper type set in the print setting process, stores more printing paper than the number of prints, and colors the color material (ink or toner). ) Is greater than or equal to the estimated usage of color material. The device selected in this way is also called a compatible device.

In step S530, the control unit 210 sets the priority based on the printing speed. That is, the control unit 210 sets the priority of the monochrome device as the print destination candidate in descending order of printing speed. In step S540, the control unit 210 sets the priority based on the user setting. That is, when the user has set the order in which the user desires preferential use in advance, the control unit 210 sets the priority based on the setting.

In step S550, the control unit 210 determines whether or not a corresponding device as a print destination candidate exists. Specifically, the control unit 210 determines whether or not the corresponding device selected in step S520 exists as a print destination candidate. If the corresponding device exists, the control unit 210 proceeds to the process in step S560, and if the corresponding device does not exist, the control unit 210 proceeds to the process in step S570.

In step S560, the control unit 210 clearly indicates the operation display unit 230 as a corresponding device, and lists and displays the devices in order of priority. In step S570, the control unit 210 clearly indicates the non-compatible device on the operation display unit 230, and lists and displays them in order of priority. In this example, the order of priority is assumed to be the order of faster printing speed if the user has not set the order in which the user desires preferential use in advance. On the other hand, when the order in which the user desires preferential use is set in advance, the order of priority is determined by applying the user's setting in preference to the printing speed.

FIG. 4 is a flowchart showing the contents of the color device selection process according to the embodiment. In step S610, the control unit 210 executes the color device extraction process. In the color device extraction process, the control unit 210 of the personal computer 200 inquires the server 300 of the color device via the LAN 500.

The server 300 refers to the image forming apparatus database 341, extracts the color device, and returns the color device to the personal computer 200. As a result, the control unit 210 can know the color device as a print destination candidate. In this example, it is assumed that two of the three image forming devices 100 (100a to 100c), the image forming devices 100a and 100b, are candidates for printing.

In step S620, the control unit 210 executes the input / output color difference calculation process. In the input / output color difference calculation process, the control unit 210 determines the color that the sRGB input image data, which is the sRGB image data as the input image data representing the desired print target image, reproduces in the Lab color space, and the color of each color device that is CMYK. The color difference ΔE of the color reproduced in the Lab color space by the image formed on the predetermined print medium by the material is calculated. The color difference (deviation) is calculated in the Lab color space because the Lab color space is a device-independent color space (CIE L * a * b * color space), and human vision is emphasized with an emphasis on perceptual uniformity. This is because it is designed to approximate.

FIG. 5 is a flowchart showing the contents of the input / output color difference calculation process (step S620) according to the embodiment. In step S621, the color difference analysis unit 211 of the control unit 210 functions as a first color conversion unit, and is comparison that is image data of a color difference comparison color space (Lab color space in this example) for comparing color differences. The sRGB input image data (device-independent) is converted into the input image data for use by a known calculation formula. The input image data for comparison is image data having an input Lab value. As a result, the color difference analysis unit 211 can generate an input Lab value for each pixel. The input Lab value represents the gradation value in the Lab color space of the print target image intended to be reproduced.

In step S622, the color difference analysis unit 211 of the control unit 210 requests the server 300 for the ICC profiles of the two image forming devices 100a and 100b, which are candidates for printing, via the LAN 500. The color difference analysis unit 211 includes data representing the paper type and basis weight range of the printing paper in the request data, which is the data to be requested, and each image forming apparatus 100a assuming the paper type and basis weight range of the printing paper. , 100b ICC profile is required. In this example, the output profile and the simulation profile representing the characteristics of the image forming unit 120 of the image forming apparatus 100 are set using the medium profile of the selected image forming medium.

In step S623, the color difference analysis unit 211 functions as a second color conversion unit, and an output image for reproducing comparative input image data with a plurality of color materials (CMYK in this example) based on each output profile. Converted to data (CMYK image data), converted the color space of the output image data based on each simulation profile, and converted the color space of the color difference comparison color space (Lab color space in this example). Convert to. The output image data for comparison is image data having an output Lab value. The output Lab value represents a gradation value (simulation value) in the Lab color space of the image to be printed that is actually reproduced by the image forming devices 100a and 100b.

In step S624, the color difference analysis unit 211 functions as a color difference calculation unit, and calculates the color difference ΔE for each of the two image forming devices 100a and 100b. The color difference ΔE is the difference between the output Lab value and the input Lab value, and is calculated for each pixel.

In step S625, the color difference analysis unit 211 acquires the maximum value ΔE_max of the color difference ΔE for each of the two image forming devices 100a and 100b. In step S626, the color difference analysis unit 211 generates a histogram of the color difference ΔE in the range from zero color difference to the maximum value ΔE_max for each of the two image forming devices 100a and 100b.

FIG. 6 is an explanatory diagram showing the content of the cumulative relative frequency of the color difference ΔE according to the embodiment. FIG. 6A shows an example of the cumulative relative frequency of the color difference. The cumulative relative power is represented by a line graph showing the cumulative number of pixels, which is the cumulative number of pixels in order from the pixel having the smallest color difference ΔE. The color difference E_90th is the color difference ΔE when the cumulative relative power of the pixels when the color difference ΔE is increased from zero becomes 90%. The cumulative relative frequency is not limited to 90%, and other predetermined ratios can be used and may be set by the user.

FIG. 6B shows the cumulative relative power of the color difference ΔE of the two image forming devices 100a and 100b and the histogram of the color difference. The histogram of the color difference ΔE shows the frequency (frequency) of the number of pixels in each color difference ΔE. The horizontal axis shows the color difference ΔE in the range from zero to the maximum value ΔE_max. The vertical axis shows the cumulative relative frequency of the color difference ΔE in the range of 0% to 100%. In this example, it is assumed that the color difference analysis unit 211 has acquired the maximum value ΔEa_max of the color difference of the image forming apparatus 100a and the maximum value ΔEb_max of the color difference of the image forming apparatus 100b.

The frequency curve a1 (thick solid line) shows a histogram of the color difference ΔEa of the image forming apparatus 100a. The frequency curve b1 (thin solid line) shows a histogram of the color difference ΔEb of the image forming apparatus 100b. The frequency curve a2 (thick dotted line) shows the cumulative relative power of the color difference ΔEa of the image forming apparatus 100a. The frequency curve b2 (thin dotted line) shows the cumulative relative power of the color difference ΔEb of the image forming apparatus 100b.

In step S627, the color difference analysis unit 211 calculates the color difference E_90th (also referred to as a specific color difference) when the cumulative relative power is 90% in the histogram of the color difference ΔE for each of the two image forming devices 100a and 100b. In this example, the color difference analysis unit 211 calculates the color difference Ea_90th of the image forming apparatus 100a and the color difference Eb_90th of the image forming apparatus 100b.

In step S630 (see FIG. 4), the device selection unit 212 compares the color difference E_90th with the preset first threshold Th1 and sets a device having a color difference E_90th smaller than the first threshold Th1 as a print destination candidate. Select as a color device. In this example, it is assumed that the device selection unit 212 has selected both of the two image forming devices 100a and 100b.

In step S640, the device selection unit 212 compares the color difference E_90th of the two image forming devices 100a and 100b with each other, and sets the device having a relatively small color difference E_90th to a high priority. In this example, the device selection unit 212 sets the priority of the image forming apparatus 100a to the image forming apparatus 100b because the color difference Ea_90th of the image forming apparatus 100a is smaller than the color difference Eb_90th of the image forming apparatus 100b (see FIG. 6B). Set higher than the priority of.

The sRGB image data representing the image to be printed is generated by a user (for example, a designer or a photographer). Users generally use base colors that occupy 50% or more of the entire image, blended colors that occupy 20% to 40% of the entire image (assorted colors), and emphasized colors that occupy less than 10% of the entire image. Create an image by arranging the accent color). In general, base colors and blended colors are intended to accurately reproduce their own colors, whereas emphasized colors are compared to base colors and blended colors in order to activate the entire image and enhance the base colors. Contrast color reproduction is intended. Therefore, especially when the base color and the blended color of the image to be printed are accurately reproduced, the output tends to be as intended by the user.

On the other hand, Patent Document 1 proposes a technique for selecting an image forming apparatus capable of expressing a color close to the color of the image data based on the average value of the color difference. On the other hand, the inventor of the present application has found that the method based on the average value of the color difference may separate the evaluation of the image forming apparatus from the evaluation based on the human visual sense due to the influence of so-called singular points. The singularity is an isolated specific frequency region with a large color difference in the frequency distribution of the color difference, as shown in FIG. 6 (b). In this example, the average value of the color difference is larger in the image forming apparatus 100a than in the image forming apparatus 100b due to the influence of the singularity.

However, based on the human visual sense, if it is possible to accurately reproduce the basic colors and the blended colors that occupy the main part of the image, the reproduced image can be obtained as the user intended. In this respect, the evaluation of the device based on the cumulative relative power has an advantage over the evaluation of the device based on the average value of the color difference. In addition, users generally do not want to reproduce all colors uniformly and accurately, with colors that they are particular about and want to reproduce accurately (for example, base colors) and colors that do not necessarily need to be reproduced accurately. Is often used. That is, the demand for color reproducibility is also light.

In this example, the image forming apparatus 100a has a color distribution due to singular points in the histogram a1 of the color difference ΔE, but 90% of the whole, that is, the color difference ΔE of most of the pixels has a distribution close to zero. are doing. Therefore, the image forming apparatus 100a may have accurate reproducibility in the base color and the blended color as compared with the image forming apparatus 100b.

In step S650, the device selection unit 212 narrows down (selects) a print destination candidate from the color devices as print destination candidates based on the printing material. Specifically, the device selection unit 212 can use the paper type and basis weight range as the printing paper type set in the print setting process, stores more printing paper than the number of prints, and colors the color material (ink or). Select a device whose toner) is equal to or greater than the estimated amount of color material used.

In step S660, the device selection unit 212 has a color gamut of sRGB image data representing the image to be printed, in which the maximum value ΔE_max is less than the preset second threshold Th2 from the color devices as print destination candidates. Extract the devices that cover. In this example, it is assumed that the device selection unit 212 determines that the maximum value ΔEa_max of the color difference of the image forming apparatus 100a and the maximum value ΔEb_max of the color difference of the image forming apparatus 100b are both less than the second threshold value Th2. ..

FIG. 7 is an explanatory diagram showing a comparison of the color gamuts (gamuts) of the input image and the output image according to the embodiment. The curve GI indicates the color gamut of the sRGB color space, which is the color space of the sRGB image data representing the image to be printed. The curve Ga indicates a color gamut that can be reproduced on a predetermined printing paper designated by the image forming apparatus 100a in the print setting process. The curve Gb indicates a color gamut that can be reproduced by the image forming apparatus 100b on a predetermined printing paper. The color gamut ID1 indicates a color gamut to be reproduced in the first input image data. The color gamut ID2 indicates a color gamut to be reproduced in the second input image data.

When the color gamut of the sRGB image data representing the image to be printed is the first input image data (color gamut ID1), the first input image data can be reproduced by the image forming apparatus 100b, while image forming. The device 100a contains colors that cannot be reproduced. When the color gamut of the sRGB image data representing the image to be printed is the second input image data (color gamut ID2), both the image forming apparatus 100a and the image forming apparatus 100b have a reproducible color gamut. It shows that there is. In this example, it is assumed that the device selection unit 212 selects both of the second input image data (color gamut ID 2) as print destination candidates. The device selected in this way is also called a compatible device.

In step S670, the control unit 210 determines whether or not there is a corresponding device selected as a print destination candidate. If the corresponding device exists, the control unit 210 advances the process to step S680, and if the corresponding device does not exist, the control unit 210 advances the process to step S690.

In step S680, the control unit 210 clearly indicates the operation display unit 230 as a corresponding device, and displays the list in order of priority. In step S690, the control unit 210 clearly indicates the non-compatible device on the operation display unit 230, and lists and displays them in order of priority. In this example, the operation display unit 230 clearly indicates that the image forming apparatus 100a has a higher priority than the image forming apparatus 100b (step S680).

In this example, the control unit 210 clearly indicates that the first input image data (color gamut ID1) is the corresponding device, and displays only the image forming apparatus 100b. (Step S680). As shown in FIG. 2, the control unit 210 repeats the processes of steps S400 to S600 every time the print setting is changed (step S700).

Further, the control unit 210 functions as a third color conversion unit, converts the comparison output image data into display image data for display on the operation display unit 230 based on the monitor profile, and causes the operation display unit 230 to display the comparison output image data. It is also possible to display an image represented by the input image data in a color reproducible by the image forming apparatus 100. This is because the color space of the monitor is generally wider than the color space of printing. At this time, the operation display unit 230 can also display a display (for example, a symbol or a symbol) for specifying an image area reproduced in a color having the maximum color difference.

Further, the control unit 210 can display a histogram of the cumulative relative power and the color difference of each compatible device (see FIG. 6B) on the operation display unit 230 and provide the user with reference information when selecting the device. .. In addition, the operation display unit 230 accepts user input for specifying a part of the color difference range of the histogram, and displays a display for specifying an image area to be reproduced with the color of the part of the color difference range specified according to the user input. It can also be displayed.

When the control unit 210 has an image area reproduced in the color of the singular point in a part of the area, the control unit 210 is an image reproduced in the color of the singular point with symbols or symbols such as lines and arrows surrounding the area. The area can be indicated. This allows the user to confirm whether or not the color of the singular point is used in the image region where the color reproducibility is important.

In step S800, the control unit 210 prints on a specific image forming device 100 (image forming devices 100a, 100b in this example) from a plurality of image forming devices 100 (image forming devices 100a to 100c in this example). The user can select the image forming apparatus 100a from the print destination candidates and specify it as the print destination. The control unit 210 generates a print job based on the input image data, sends the print job to the image forming apparatus 100a designated as the printing destination, and causes the image forming to be executed.

As described above, the image forming system 10 according to the present embodiment pays attention to the frequency distribution of the color difference, suppresses the influence of the singular point on the frequency distribution, and has high color reproducibility with an evaluation standard close to the user's visual sense. An image forming apparatus can be selected. As described above, the image forming system 10 according to the present embodiment can provide a user-friendly user interface from the user's point of view and support the selection of an appropriate device.

The present invention can be implemented not only in the above embodiment but also in the following modifications.

Modification 1: In the above embodiment, the color difference is calculated in the Lab color space, but the color space for calculating the color difference is not limited to the Lab color space. The color space for calculating the color difference may be a color space for color difference comparison, which is a common color space for comparing color differences. However, the Lab color space is a device-independent color space (CIE L * a * b * color space), and is designed to approximate human vision with an emphasis on perceptual uniformity. There is an advantage that evaluation can be performed according to visual sensitivity.

Modification 2: In the above embodiment, a personal computer is configured as an image formation control device, a specific image forming device is selected from a plurality of image forming devices, and an image is formed by the specific image forming device based on input image data. However, a server that functions as an image forming device or a print server may be configured to function as an image forming control device.

Modification 3: In the above embodiment, the feedback for measuring the image formation state of the plurality of image forming devices is not performed, but the color may be measured and fed back. The feedback results may be centrally managed by, for example, a server, and the image forming system may be configured so as to form an output profile and a simulation profile of each image forming apparatus. As a result, the image forming system 10 can suppress the influence of aging of each image forming apparatus 100, and can realize printing with high reproducibility by using a printing medium for which a medium profile is not prepared.

10 Image forming system 100 Image forming apparatus 110, 210, 310 Control unit 120 Image forming unit 121 Color conversion processing unit 122 Halftone processing unit 130 Image reading unit 140, 240, 340 Storage unit 150 Communication interface unit 200 Personal computer 210 Control unit 230 Operation display unit 300 Server 341 Image forming device database

Claims (8)

An image formation control device for selecting a specific image forming device from a plurality of image forming devices and causing the specific image forming device to perform image formation based on input image data.
A first color conversion unit that converts the input image data into comparison input image data, which is image data of a color space for color difference comparison for comparing color differences, and
Output image data for acquiring an output profile and a simulation profile representing the characteristics of each of the plurality of image forming devices, and reproducing the comparison input image data with a plurality of color materials based on the acquired output profiles. The color space of the converted output image data is converted for each of the plurality of image forming devices based on the acquired simulation profiles, and each comparison output is the image data of the color difference comparison color space. A second color conversion unit that converts to image data,
The color difference between the comparison input image data and each comparison output image data is compared for each pixel, and a specific color difference, which is a color difference when the cumulative relative frequency of the color difference becomes a predetermined ratio, is obtained for each of the plurality of image forming devices. And the color difference calculation unit to calculate
A device selection unit that preferentially selects the image forming apparatus having a small specific color difference over the image forming apparatus having a large specific color difference.
An image formation control device comprising. The image formation control device according to claim 1, further
An operation display unit with the characteristics defined in the monitor profile,
A third color conversion unit that converts each comparison output image data into display image data for display on the operation display unit based on the monitor profile.
With
The operation display unit is an image formation control device that displays an image represented by the input image data in a color reproducible by the specific image forming device. The image formation control device according to claim 2.
The color difference calculation unit calculates the maximum color difference, which is the maximum value of each specific color difference of the plurality of image forming devices.
The operation display unit is an image formation control device that displays a display that identifies an image region reproduced in a color having the maximum color difference. The image formation control device according to claim 3.
The color difference calculation unit generates a histogram in the range from zero color difference to the maximum value.
The operation display unit displays the histogram, accepts user input for specifying a part of the color difference range of the histogram, and reproduces the image area with colors of the specified part of the color difference range in response to the user input. An image formation control device that displays a display for identifying a display. The image formation control device according to any one of claims 2 to 4.
The operation display unit receives an image formation setting input including selection of an image formation medium, and receives an image formation setting input.
The output profile and the simulation profile are image formation control devices set by using a medium profile which is a profile of the selected image forming medium. The image formation control device according to any one of claims 1 to 5.
With the plurality of image forming devices
An image forming system comprising. This is an image formation control method for selecting a specific image forming apparatus from a plurality of image forming apparatus and causing the specific image forming apparatus to execute image formation based on input image data.
A first color conversion step of converting the input image data into comparison input image data, which is image data of a color space for color difference comparison for comparing color differences, and
Output image data for acquiring an output profile and a simulation profile representing the characteristics of each of the plurality of image forming devices, and reproducing the comparison input image data with a plurality of color materials based on the acquired output profiles. The color space of the converted output image data is converted for each of the plurality of image forming devices based on the acquired simulation profiles, and each comparison output is the image data of the color difference comparison color space. The second color conversion process to convert to image data,
The color difference between the comparison input image data and each comparison output image data is compared for each pixel, and a specific color difference, which is a color difference when the cumulative relative frequency of the color difference becomes a predetermined ratio, is obtained for each of the plurality of image forming devices. The color difference calculation process to be calculated in
A device selection step of preferentially selecting an image forming apparatus having a small specific color difference over an image forming apparatus having a large specific color difference.
An image formation control method comprising. An image formation control program for selecting a specific image forming device from a plurality of image forming devices and controlling an image forming control device for executing image forming based on input image data in the specific image forming device.
A first color conversion unit that converts the input image data into comparison input image data, which is image data of a color space for color difference comparison for comparing color differences.
Output image data for acquiring an output profile and a simulation profile representing the characteristics of each of the plurality of image forming devices, and reproducing the comparison input image data with a plurality of color materials based on the acquired output profiles. The color space of the converted output image data is converted for each of the plurality of image forming devices based on the acquired simulation profiles, and each comparison output is the image data of the color difference comparison color space. Second color conversion unit that converts to image data,
The color difference between the comparison input image data and each comparison output image data is compared for each pixel, and a specific color difference, which is a color difference when the cumulative relative frequency of the color difference becomes a predetermined ratio, is obtained for each of the plurality of image forming devices. An image formation control device that causes the image formation control device as a device selection unit that preferentially selects the color difference calculation unit and the image formation device having a small specific color difference over the image formation device having a large specific color difference.

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