JP2012231388A - Color conversion table editing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently effectively utilize color gamuts of a device which performs output after color reproduction.SOLUTION: A color conversion table editing apparatus 10 comprises a first color gamut acquisition section 21 which acquires a color gamut of a second output device as a first color gamut, a second color gamut acquisition section 22 which acquires as a second color gamut a color gamut in the case where a color outputted by a first output device is reproduced by a second output device using a color conversion table of the second output device, a display section 11 which displays a difference between the first color gamut and the second color gamut as a difference of color gamuts, an operation input section 12 which receives the input of adjustment to the second color gamut on the basis of the displayed difference of color gamuts, an editing point input section 26, an editing amount input section 27, an editing range input section 28, and an editing arithmetic section 29 which adjusts the color conversion table of the second input device in such a manner that a color gamut after color reproduction using the color conversion table of the second output device for color reproduction of the first output device becomes the second color gamut after the adjustment, on the basis of contents of the received input.

Description

  The present invention relates to a color conversion table editing apparatus.

  Conventionally, color management for performing color reproduction processing for reproducing colors by a certain output device (hereinafter referred to as “first output device”) by different output devices (hereinafter referred to as “second output device”) There is a system. The color management system uses the color conversion table of each output device to reproduce the color output by the first output device with the color included in the color gamut that can be output by the second output device.

  In addition, in the color management system, there is a color conversion table editing device for displaying the color gamut of the first output device and the color gamut of the second output device in a switchable manner and adjusting each color gamut ( For example, Patent Document 1).

Japanese Patent No. 4347435

  By the way, the color gamut inherent to the second output device, that is, the color gamut of the second output device when outputting colors without being restricted by the color reproduction of the first output device (hereinafter referred to as “first color”). The color gamut (hereinafter referred to as “second color gamut”) when the color output by the first output device is reproduced by the second output device is narrower than that described in “gamut”. Further, the second color gamut may be inferior in appearance such as vividness due to the narrow color gamut compared to the first color gamut.

  On the other hand, in the color reproduction process, there are cases where priority is given to visual quality such as vividness over accurate color reproduction. In such a case, the visual quality is improved by editing the color conversion table of the second output device so as to utilize the color gamut that is not used in the second color gamut in the first color gamut. May be possible.

  However, the conventional color conversion table editing device cannot fully utilize the color gamut of the device that performs output after color reproduction, that is, the second output device. This is because the conventional color conversion table editing apparatus cannot confirm the difference between the first color gamut and the second color gamut, and the user can use the second color gamut in the first color gamut. This is because it was difficult to grasp the unused color gamut.

  An object of the present invention is to provide a color conversion table editing apparatus that can fully utilize the color gamut of an apparatus that performs output after color reproduction.

  The invention according to claim 1 is a color conversion table editing device for editing a color conversion table for reproducing the color output by the first output device by the second output device, wherein the second output First acquisition means for acquiring the color gamut of the device as a first color gamut, and the second output by using the color conversion table of the second output device for the color output by the first output device. Second acquisition means for acquiring a color gamut when reproduced by the apparatus as a second color gamut; and display means for displaying a difference between the first color gamut and the second color gamut as a color gamut difference. And an accepting means for accepting an input of adjustment for the second color gamut within the range of the color gamut displayed by the display means, and based on the contents of the input accepted by the accepting means, the first The color output by the first output device is the second output. Editing means for editing the color conversion table of the second output device so that the color gamut when reproduced by the second output device using the color conversion table of the device becomes the second color gamut after adjustment And.

  A second aspect of the present invention is the color conversion table editing apparatus according to the first aspect, in which a difference between the first color gamut and the second color gamut is indicated based on a predetermined specific criterion. Specifying means for specifying the candidate points, and the display means displays the candidate points.

  A third aspect of the present invention is the color conversion table editing apparatus according to the second aspect, wherein the first color gamut and the first color gamut are based on colors of red, yellow, green, cyan, blue, and magenta. Calculating means for calculating a difference from the two color gamuts, wherein the display means is based on the difference calculated by the calculating means and is at least one of red, yellow, green, cyan, blue and magenta. A feature is that a difference in color gamut based on color is displayed as a candidate point.

  A fourth aspect of the present invention is the color conversion table editing apparatus according to the second or third aspect, wherein the display means includes the first color gamut and the second color among the plurality of candidate points. A list that preferentially shows candidate points having a larger difference from the color gamut is displayed.

  A fifth aspect of the present invention is the color conversion table editing apparatus according to any one of the second to fourth aspects, wherein the accepting unit is configured to select the second color gamut from a plurality of the candidate points. Selection means for selecting candidate points used for the adjustment, and determination means for determining an adjustment amount of the second color gamut based on the candidate points selected by the selection means.

  A sixth aspect of the present invention is the color conversion table editing apparatus according to any one of the first to fifth aspects, further comprising designation means for designating a range of adjustment of the second color gamut. Features.

  A seventh aspect of the present invention is the color conversion table editing apparatus according to the sixth aspect, wherein the display means displays a range designated by the designation means.

  The invention according to claim 8 is the color conversion table editing device according to any one of claims 1 to 7, wherein the color gamut of the first output device is acquired as a third color gamut. 3, and the display unit displays a difference between the second color gamut and the third color gamut.

  According to the present invention, the color gamut of an apparatus that performs output after color reproduction can be fully utilized.

It is a figure which shows an example of the main structures of the color management system containing the color conversion table editing apparatus which is one Embodiment of this invention. It is a block diagram which shows an example of the main structures of a color conversion table editing apparatus. It is a functional block diagram which shows an example of the main functions of a calculating part. It is a figure which shows an example of a structure of DP. It is a figure which shows an example of a structure of DLP. It is an image figure which shows the acquisition example of the 2nd color gamut using DP or DP and DLP. FIG. 6A is an image diagram showing an example of acquiring the second color gamut using DP. FIG. 6B is an image diagram illustrating an example of acquiring the second color gamut using DP and DLP. It is a figure which shows the example of a display of a color conversion table edit screen. It is a flowchart which shows an example of the flow of the color conversion table edit process using DP. 6 is a flowchart illustrating an example of a flow of display processing of a first color gamut. 12 is a flowchart illustrating an example of a flow of display processing of a second color gamut. It is a flowchart which shows an example of the flow of an edit candidate point specific process. It is a flowchart which shows an example of the flow of the color conversion table edit process using DP and DLP. It is a flowchart which shows an example of the display process of the 2nd color gamut using DLP. It is a figure which shows the example of a display of the color conversion table edit screen in a modification.

  Hereinafter, a color conversion table editing apparatus 10 according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, embodiment is an example of this invention and is not limited to this.

FIG. 1 is a diagram illustrating an example of a main configuration of a color management system 1 including a color conversion table editing apparatus 10 according to an embodiment of the present invention.
The color management system 1 includes a terminal 2, a controller 3, an image forming apparatus 4, and a color conversion table editing apparatus 10, and these components are connected to each other via a line 5 so as to communicate with each other.

  The terminal 2 is, for example, a computer, executes software such as a predetermined printer driver, and outputs data (print job) for image formation by the image forming apparatus 4.

Based on the print job output from the terminal 2, the controller 3 generates image data in a format that allows the image forming apparatus 4 to form an image and outputs the image data to the image forming apparatus 4.
Specifically, the controller 3 performs various processing such as color conversion processing, screening, and rasterization on the original data of the image data included in the print job to generate image data. The color conversion process is a process for performing color reproduction using a color conversion table in order to reproduce the color output by the output device of the first output device by the second output device. Performs color conversion processing for reproducing the colors of the output devices other than the image forming device 4 with the colors of the print output by the image forming device 4. Examples of output devices other than the image forming device 4 include other image forming devices, display devices, and other output devices that handle other colors.

  The image forming apparatus 4 forms an image based on the image data output from the controller 3.

  The line 5 is, for example, a communication network line constructed using a dedicated line or an existing general public line, and various line forms such as a LAN (Local Area Network) and a WAN (Wide Area Network) are applied. It is possible.

The color conversion table editing apparatus 10 performs various processes relating to the color conversion table, such as editing of the color conversion table used by the controller 3 in the color conversion process.
FIG. 2 is a block diagram illustrating an example of a main configuration of the color conversion table editing apparatus 10.
The color conversion table editing device 10 includes a display unit 11, an operation input unit 12, a communication control unit 13, a command unit 14, a measurement unit 15, a calculation unit 20, and the like, and these components are connected via a bus 16. Is done.

  The display unit 11 includes, for example, a display device such as a liquid crystal display device or an organic electroluminescence (EL) display device, and performs display according to various processing contents performed by the color conversion table editing device 10.

  The operation input unit 12 includes, for example, an input device such as a keyboard and a mouse, receives various operation inputs to the color conversion table editing device 10, and generates and outputs electrical signals corresponding to the received input contents. The calculation unit 20 performs processing according to the content input through the operation input unit 12.

  The communication control unit 13 includes, for example, an interface for connection to a communication network via the line 5, a circuit (not shown) for performing signal processing for performing communication, and the like, and is connected to a predetermined line such as a wired or wireless LAN Communication control of information is performed with each device of the color management system 1 via the line 5 according to the communication standard.

The command unit 14 outputs a command (chart output command) for outputting a color chart (chart) for creating a color conversion table to an output device (for example, the image forming device 4) that handles colors.
For example, when the command output unit 14 outputs a chart output command to the image forming apparatus 4 via the line 5, the image forming apparatus 4 prints out the chart.

The measurement unit 15 includes an interface (not shown) or the like for connecting to an external colorimeter 6 and measures colors included in the chart via the connected colorimeter 6.
Here, the chart used for the color measurement by the measurement unit 15 may be, for example, a chart output according to a chart output command or the like by the command unit 14 or a chart prepared in advance.

The computing unit 20 includes a storage device such as a CPU, RAM, ROM, and flash memory (not shown), for example, and reads various programs, data, and the like stored in the ROM and the storage device and performs various processes.
In addition, the calculation unit 20 generates a color conversion table based on the measurement result of the chart color by the measurement unit 15. In addition, the calculation unit 20 performs various processes related to the color conversion table.

FIG. 3 is a functional block diagram illustrating an example of main functions of the arithmetic unit 20.
The calculation unit 20 includes a first color gamut acquisition unit 21, a second color gamut acquisition unit 22, a color gamut display control unit 23, a color difference calculation unit 24, an edit candidate point display control unit 25, an edit point input unit 26, and an edit amount input. A unit 27, an edit range input unit 28, an edit operation unit 29, and a storage unit 30.

The first color gamut acquisition unit 21 acquires the color gamut (first color gamut) of the second output device based on the color conversion table.
Hereinafter, an example using a color management method based on an ICC (International Color Consortium) profile will be described as an example of description of acquisition of a color gamut based on a color conversion table in the present embodiment.

  As a color conversion table used in the color management method based on the ICC profile, for example, there are a device profile (Device Profile: DP) and a device link profile (Device Link Profile: DLP). Hereinafter, description will be made sequentially.

FIG. 4 is a diagram illustrating an example of the configuration of the DP.
DP is a look-up table (LUT) indicating the correspondence between model-dependent values and model-independent values.
The model-dependent value indicates a color value corresponding to a specific output device. For example, the color material color (cyan (C), magenta (M), yellow (Y), and black (B)) used in the image forming apparatus 4 is used. Corresponding to Even if the color space used for color reproduction is the same, such as the type of colorant (for example, CMYK, etc.), the model-dependent value differs depending on each output device.
The model-independent value indicates a color value in a predetermined color space that does not depend on a specific output device. The model-independent value is a color value based on a predetermined color space such as a Sealab (CIE L * a * b *) color system.

The DP includes an LUT for obtaining a model-independent value from the model-dependent value (for example, “A2B” shown in FIG. 4) and an LUT for obtaining a model-dependent value from the model-independent value (for example, “B2A” shown in FIG. 4). Etc.) individually.
Further, as shown in FIG. 4, the DP may have a preset rendering intent. The rendering intent includes, for example, “perception” that prioritizes natural color reproduction, “colorimetry” that prioritizes colorimetric correctness, and “saturation” that prioritizes color vividness. The DP in which the rendering intent is set has an LUT that indicates a correspondence relationship between a plurality of model-dependent values and model-independent values that are individually provided in accordance with differences in color reproduction policies.

FIG. 5 is a diagram illustrating an example of the configuration of the DLP.
The DLP is a look-up table (LUT) that indicates the correspondence between two different model-dependent values. In other words, the DLP is a color conversion table that can convert colors between two different output devices.

  The calculation unit 20 is a color conversion table generated based on a chart of the image forming apparatus 4, a color conversion table generated based on a chart of another output device, a color conversion table provided in advance, or the like. Is stored in a storage device or the like.

  For example, the first color gamut acquisition unit 21 acquires the color gamut of the image forming apparatus 4 based on the color conversion table of the image forming apparatus 4. Specifically, the first color gamut acquisition unit 21 reads the DP of the image forming apparatus 4 and acquires a model-independent value corresponding to the model-dependent color of the image forming apparatus 4.

  The second color gamut acquisition unit 22 acquires a color gamut serving as a reference for color reproduction based on the color conversion table. That is, the second color gamut acquisition unit 22 acquires a color gamut (second color gamut) when the color output by the first output device is reproduced by the second output device.

The second color gamut acquisition unit 22 can acquire the second color gamut using DP or DP and DLP.
When acquiring the second color gamut using the DP, as shown in FIG. 6A, the second color gamut acquisition unit 22 depends on the model of the first output device based on the DP of the first output device. Get the machine independent value corresponding to the value. Next, based on the obtained model-independent value and the DP of the second output device, a model-dependent value of the second output device corresponding to the obtained model-independent value is acquired. Then, the second color gamut acquisition unit 22 sets the model-dependent value of the second output device obtained based on the model-dependent value of the second output device obtained and the DP of the second output device. The corresponding machine independent value is acquired as the second color gamut. The DP of the first output device is called a source profile or a target profile. The DP of the second output device is called a destination profile or a printer profile.

  On the other hand, when acquiring the second color gamut using DP and DLP, as shown in FIG. 6B, the second color gamut acquisition unit 22 uses the model-dependent value of the first output device and the second color gamut. The model-dependent value of the second output device corresponding to the model-dependent value of the first output device is acquired by the DLP that associates the model-dependent value of the output device. Then, the second color gamut acquisition unit 22 sets the model-dependent value of the second output device obtained based on the model-dependent value of the second output device obtained and the DP of the second output device. The corresponding machine independent value is acquired as the second color gamut.

  The color conversion table editing apparatus 10 according to the present embodiment is, for example, a color conversion table of another image forming apparatus (for example, an offset printing machine) (not shown) or a generally known color conversion table of the first output device. A predetermined profile (for example, JapanColor (registered trademark)) can be used. The computing unit 20 can generate a DP corresponding to the color measurement result of a chart of another image forming apparatus (not shown). Further, the arithmetic unit 20 determines whether the other image forming apparatus (not shown) and the image forming apparatus 4 are based on the color measurement result of the chart of the other image forming apparatus (not shown) and the colorimetric result of the chart of the image forming apparatus 4. A DLP for performing color conversion between each other can be generated. The calculation unit 20 can also use a predetermined DP (for example, JapanColor (registered trademark) DP) prepared in advance.

  The color gamut display control unit 23 causes the display unit 11 to display the color gamut acquired by the first color gamut acquisition unit 21 and the second color gamut acquisition unit 22. Specifically, the color gamut display control unit 23 displays the color gamut acquired by the first color gamut acquisition unit 21 and the second color gamut acquisition unit 22 on the color conversion table editing screen.

FIG. 7 is a diagram illustrating a display example of the color conversion table editing screen.
As shown in FIG. 7, the color conversion table editing screen has a region (color gamut view) for displaying a color gamut. The color gamut view is an area in which the color gamut is displayed by a display method corresponding to a color space of a model independent value (for example, CIE L * a * b *). In the example shown in FIG. 7, the color gamut view displays the color gamut using the a * -b * plane, but other planes (L * -a * plane and L * -b * plane), 3D Display using (L * -a * -b * color space) can also be performed. The display method of the color gamut view can be changed, for example, by selecting a “display space” button shown in FIG.

  As shown in FIG. 7, the color gamut display control unit 23 is acquired by the hexagonal frame H <b> 1 indicating the first color gamut acquired by the first color gamut acquisition unit 21 and the second color gamut acquisition unit 22. A hexagonal frame H2 indicating the second color gamut is displayed on the color gamut view. Here, the space between the frame H1 indicating the first color gamut and the frame H2 indicating the second color gamut, that is, the degree of separation between the frame H1 and the frame H2 in the color gamut view, Displayed as the difference between the color gamut and the second color gamut (difference in color gamut).

The color difference calculation unit 24 calculates a difference between the second color gamut and the first color gamut based on a predetermined specific criterion.
Specifically, the color difference calculation unit 24, for example, of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M) in the a * -b * plane. A difference (color difference d) between the first color gamut and the second color gamut is calculated for each of the hues of each single color and each of the hues corresponding to the midpoint between adjacent colors of these single colors.

  It should be noted that the hue of each single color of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M) and the midpoint between adjacent colors of these single colors. When all hues are represented by angles of 0 to 360 degrees on the plane, the hues corresponding to red (R), yellow (Y), green (G), cyan (C), blue (B), Each magenta (M) has a hue that divides 360 degrees in increments of 60 degrees, and an intermediate point between adjacent colors in a single color further divides adjacent colors into two. That is, the hue of each single color of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M) and the midpoint between adjacent colors of these single colors As for the hue corresponding to, all hues are divided in units of 30 degrees.

The edit candidate point display control unit 25 displays candidate points indicating the difference between the second color gamut and the first color gamut on the color conversion table edit screen displayed on the display unit 11 based on a predetermined specific criterion. Display.
Specifically, the edit candidate point display control unit 25, for example, each of the single colors of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M). For each of the hues and hues corresponding to the midpoints between adjacent colors of these single colors, a predetermined value having a larger difference value between the first color gamut and the second color gamut calculated by the color difference calculation unit 24. Color values corresponding to a number (for example, six) of color differences are specified as edit candidate points, and the edit candidate points are displayed. The edit candidate point functions as a navigation element that can be used when editing a second color gamut described later.

  In the present embodiment, each single color of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M) and the middle of adjacent colors among these single colors. Among the colors corresponding to the points, a predetermined number (for example, six) of edit candidate points having a larger difference between the first color gamut and the second color gamut calculated by the color difference calculation unit 24 are displayed.

In the case of the example shown in FIG. 7, six edit candidate points Q1 to Q6 are displayed so as to be superimposed on a frame H2 indicating the second color gamut. In addition, the edit limit points R1 to R6 are displayed so as to overlap the frame H1 indicating the first color gamut so as to correspond to the six edit candidate points Q1 to Q6.
The edit limit points R1 to R6 indicate limit color values that can expand the color gamut for each of the edit candidate points Q1 to Q6. In other words, in editing the second color gamut, the user changes the color value corresponding to the edit candidate point Q1 within a range from the color value of the edit candidate point Q1 to the color value of the edit limit point R1. be able to. Similarly, in editing the color value of the second color gamut, the user can adjust the second color gamut within the range of the difference between the first color gamut and the second color gamut.

  More specifically, the process relating to the display of the edit candidate points will be described. The color difference calculation unit 24 has the highest saturation in any of the hues divided by a predetermined angle (for example, the unit of 30 degrees). A color value is specified for each of the first color gamut and the second color gamut. Here, it is assumed that the color value n of the identified first color gamut is the color value n and the second color gamut is the color value m. Then, the color difference calculation unit 24 calculates a difference (color difference d) between the color value m and the color value n, and sets the calculated color difference d as the maximum color difference in the hue. The color difference calculation unit 24 calculates the color value n, the color value m, and the color difference d for all the hues constituting the hue divided by a predetermined angle, and calculates the maximum color difference of each hue. Then, the edit candidate point display control unit 25 sets the color value m of the second color gamut indicating a larger predetermined number (for example, six) of color differences among the calculated maximum color differences as an edit candidate point. The color value n corresponding to the color value m determined as the editing candidate point is set as an editing limit point and displayed on the color conversion table editing screen. Here, the magnitude of the value of the color difference d corresponds to the magnitude of the distance between the edit candidate point and the edit limit point in the color gamut view. In the present embodiment, an arrow from each edit candidate point to the edit limit point of the edit candidate point is displayed. That is, the arrow indicates the range of the color gamut that can be adjusted (enlarged) for each editing candidate point.

  The edit point input unit 26, the edit amount input unit 27, and the edit range input unit 28 are the second within the range of the difference between the first color gamut and the second color gamut, which is performed via the operation input unit 12 or the like. The input of adjustment for the color gamut of is accepted.

The edit point input unit 26 selects candidate points used for adjustment of the second color gamut from among a plurality of edit candidate points.
Specifically, the edit point input unit 26 receives a selection for any one of the edit candidate points displayed on the color conversion table edit screen and reflects the selection on the color conversion table edit screen. For selection of the edit candidate point, for example, a selection input for any of the edit candidate points displayed in the color gamut view or a “select from large color difference area” pull-down menu of the color conversion table edit screen shown in FIG. 7 is used. This can be done by selection or the like. The pull-down menu of “Select from large color difference area” displays, for example, a hue (Area) including an edit candidate point having a larger color difference d.
Further, as shown in FIG. 7, the edit point input unit 26 displays the input device value and the output device value corresponding to the selected edit candidate point on the color conversion table edit screen. Here, the input device value indicates the color value of the first output device. The output device value indicates the color value of the second output device. That is, the edit point input unit 26 indicates the color value corresponding to the selected edit candidate point by the color value of the first output device and the color value of the second output device.

The edit amount input unit 27 determines the adjustment amount of the second color gamut based on the selected edit candidate point.
Specifically, the editing amount input unit 27 determines the numerical value of the correction amount shown in FIG. For example, when the “brighten” button shown in FIG. 7 is operated by the user, the edit amount input unit 27 sets the color value of the selected edit candidate point to the edit limit point corresponding to the edit candidate point. The color value adjustment amount (for example, the adjustment amount of each color value of C, M, Y, and K) in the case of the color value is set to the numerical value of the correction amount shown in FIG. Further, the numerical values of the respective correction amounts shown in FIG. 7 may be individually designated and input by the user. In this case, the edit amount input unit 27 sets the designated input value to the numerical value of each color of the correction amount.

The edit range input unit 28 designates the second color gamut adjustment range (correction range).
Specifically, the edit range input unit 28 determines the correction range according to the color value of the selected edit candidate point and a predetermined correction range set according to the input operation on the color conversion table edit screen. . In the present embodiment, as the predetermined correction range, for example, correction ranges represented by character strings of “narrow”, “normal”, and “wide” are set in advance.
Here, “narrow” indicates a color gamut included in ΔE = 10 with the color value of the edit candidate point as the center. “Normal” indicates a color gamut included in ΔE = 20 with the color value of the edit candidate point as the center. “Wide” indicates a color gamut included in ΔE = 30 with the color value of the edit candidate point as the center. ΔE represents the Euclidean distance in the color space of the Sealab color system. The names of these predetermined correction ranges and their specific contents are determined by data provided in advance and stored in a ROM or a storage device. The expression of the predetermined correction range and the specific contents thereof are merely examples, and the present invention is not limited to this.

  When one of “narrow”, “normal”, or “wide” correction range is selected by the user on the color conversion table editing screen, the edit range input unit 28 displays the color value of the selected edit candidate point, A color gamut to be specifically edited is determined according to the selected correction range.

The editing operation unit 29 adjusts the color gamut when the color output by the first output device is reproduced by the second output device using the color conversion table of the second output device. The color conversion table of the second output device is edited so that
Specifically, the editing calculation unit 29 is for editing the color gamut that is the editing target in accordance with the input content received by the editing point input unit 26, the editing amount input unit 27, and the editing range input unit 28, for example. Perform the operation. First, the edit calculation unit 29 outputs the color value that has been edited according to the edit amount in accordance with the output device value set by the edit point input unit 26 and the correction amount set by the edit amount input unit 27. The device value is calculated as an edited output device value and reflected on the color conversion table editing screen. The edit calculation unit 29 also edits the color value after editing for each color value included in the color gamut corresponding to the selected edit candidate point and the correction range set by the edit range input unit 28 as in the case of the candidate point. Is calculated. Then, the editing operation unit 29 uses the B2A used for obtaining the second color gamut in the DP LUT of the second output device so that color reproduction corresponding to the calculated color value after editing is performed. Edit and adjust the LUT or DLP LUT.

  In the present embodiment, the calculation unit 20 displays a color corresponding to the input device value on the input device color display window W1 of the color conversion table editing screen, and displays a color corresponding to the output device value on the output device of the color conversion table editing screen. The color is displayed in the color display window W2, and the color corresponding to the output device value after editing is displayed in the output device color display window W3 after editing in the color conversion table editing screen. That is, the calculation unit 20 displays the color that is the reference for color reproduction in the input device color display window W1, displays the reproduction color before adjustment of the color gamut in the output device color display window W2, and after the adjustment of the color gamut. The reproduced color is displayed in the output device color display window W3 after editing.

The storage unit 30 stores the color conversion table edited by the editing operation unit 29.
Specifically, the storage unit 30 performs, for example, the DP of the image forming apparatus 4 in which the LUT changed by the editing operation unit 29 is reflected, or color conversion between the image forming apparatus 4 and another output device. Are stored in the storage device of the arithmetic unit 20.

  Note that the editing content of the color conversion table accepted by the color conversion table editing apparatus 10 of the present embodiment is not limited to editing using edit candidate points. For example, when a color value other than the editing candidate point is designated as an editing target by a user input operation, the editing point input unit 26 replaces the editing candidate point with the color value (editing) designated as the editing target. The input device value and the output device value corresponding to point) are displayed on the color conversion table editing screen. Then, the editing operation unit 29 outputs the color value corresponding to the editing amount edited according to the output device value set by the editing point input unit 26 and the correction amount set by the editing amount input unit 27. The device value is calculated as an edited output device value and reflected on the color conversion table editing screen. Then, the editing operation unit 29 also sets the edited color value for each color value included in the color gamut according to the designated editing point and the correction range set by the editing range input unit 28, as with the candidate point. calculate.

In addition, the color conversion table editing apparatus 10 according to the present embodiment can select whether or not to display edit candidate points. Specifically, the color conversion table editing device 10 stores the setting of whether or not to display the edit candidate points set by the user in the storage device or the like of the calculation unit 20.
When the setting for displaying the edit candidate points is made, the edit candidate point display control unit 25 performs processing for specifying and displaying the edit candidate points. On the other hand, when the setting for displaying the edit candidate point is not made, the edit candidate point display control unit 25 does not perform the process for specifying and displaying the edit candidate point.

Hereinafter, the flow of processing performed by the arithmetic unit 20 will be described with reference to the flowcharts of FIGS.
First, the flow of color conversion table editing processing using DP will be described with reference to the flowchart of FIG.
The arithmetic unit 20 reads the DP of the second output device to be edited (for example, the DP of the image forming device 4) (step S1). Next, the arithmetic unit 20 reads the DP of the first output device that is a reference for color reproduction (step S2). Then, the computing unit 20 determines the LUT to be referred to in the read DP according to the rendering intent selection by the user (step S3), and the first color gamut obtaining unit 21 performs the first color gamut display process ( Step S4) is performed.

Here, the display processing of the first color gamut will be described with reference to the flowchart of FIG.
First, the first color gamut acquisition unit 21 secures a memory area for storing data (color gamut solid information) constituting the color gamut solid of the first color gamut, and the color gamut solid of the first color gamut. Information is initialized (step S21). The initialization of the color gamut solid information is a color value constituting the color gamut solid for indicating the first color gamut in a model-independent color space (for example, a 3D color space of L * -a * -b *). This is to clear all information and is a general initialization process.

Next, the first color gamut acquisition unit 21 uses the A2B LUT among the DPs of the second output device to determine the model from the model-dependent value of the second output device (for example, the color value in the CMYK color space). An independent value (for example, a value of L * a * b *) is calculated (step S22).
Next, the first color gamut acquisition unit 21 determines whether or not the calculated model-independent value is included in a color gamut solid formed by the model-independent value that has already been calculated in the display process of the first color gamut. (Step S23). Here, when the calculated model independent value is not included in the color gamut solid configured by the model independent value already calculated in the display processing of the first color gamut (step S23: NO), the first color gamut. The acquisition unit 21 updates the color gamut solid information with the calculated model-independent value (step S24).

Thereafter, the first color gamut acquisition unit 21 determines whether or not model-independent values have been calculated for all colors in the model-dependent values of the second output device (step S25). Here, when the model independent values are calculated for all the colors in the model-dependent values of the second output device (step S25: YES), the first color gamut acquisition unit 21 performs color conversion based on the color gamut solid information. The color gamut solid frame (frame H1) corresponding to the space of the color gamut view according to the setting of “display space” on the table editing screen is displayed in the color gamut view (step S26), and the first color gamut display processing is terminated. To do. On the other hand, when the model independent values are not calculated for all the colors in the model dependent values of the second output device (step S25: NO), the first color gamut obtaining unit 21 proceeds to step S22.
When the calculated model independent value is included in the color gamut solid formed by the model independent value already calculated in the first color gamut display process in step S23 (step S23: YES), The one color gamut acquisition unit 21 proceeds to step S25.

After the end of the first color gamut display process, the second color gamut acquisition unit 22 uses the DP of the first output device and the DP of the second output device to perform the second color gamut display process (step S5) is sequentially performed.
Here, the display processing of the second color gamut will be described with reference to the flowchart of FIG.
First, the second color gamut acquisition unit 22 secures a memory area for storing data (color gamut solid information) constituting the color gamut solid of the second color gamut, and the color gamut solid of the second color gamut. Information is initialized (step S31).

  Next, the second color gamut acquisition unit 22 uses the A2B LUT among the DPs of the first output device, and uses the model-dependent value of the first output device (for example, the color value in the CMYK color space) as the model. An independent value (for example, a value of L * a * b *) is calculated (step S32). Next, the second color gamut acquisition unit 22 uses the B2A LUT out of the DP of the second output device to calculate the model-dependent value (for example, CMYK color) of the second output device from the calculated model-independent value. A color value in the space is calculated (step S33). Further, the second color gamut acquisition unit 22 uses a model-dependent value (for example, L * a) from the model-dependent value of the second output device calculated using the A2B LUT of the DP of the second output device. * B *) is calculated (step S34).

  Next, the second color gamut acquisition unit 22 determines whether or not the calculated model-independent value is included in a color gamut solid formed by the model-independent value that has already been calculated in the display process of the second color gamut. (Step S35). Here, when the calculated model independent value is not included in the color gamut solid formed by the model independent value already calculated in the display processing of the second color gamut (step S35: NO), the second color gamut The acquisition unit 22 updates the color gamut solid information with the calculated model-independent value (step S36).

Thereafter, the second color gamut acquisition unit 22 determines whether or not model-independent values have been calculated for all colors in the model-dependent values of the first output device (step S37). Here, when the model independent values are calculated for all the colors in the model-dependent values of the first output device (step S35: YES), the second color gamut acquisition unit 22 performs color conversion based on the color gamut solid information. A color gamut solid frame (frame H2) corresponding to the space of the color gamut view according to the setting of “display space” on the table editing screen is displayed in the color gamut view (step S38), and the second color gamut display processing is terminated. To do. On the other hand, when the model independent values are not calculated for all the colors in the model-dependent values of the first output device (step S37: NO), the second color gamut acquisition unit 22 proceeds to step S32.
When the calculated model independent value is included in the color gamut solid formed by the model independent value already calculated in the second color gamut display process in step S35 (step S35: YES), In the two-color gamut acquisition unit 22, the process proceeds to step S37.

  After the end of the second color gamut display process, the calculation unit 20 determines whether or not the setting for displaying the edit candidate points has been made (step S6). Here, when the setting for displaying the edit candidate point is made (step S6: YES), the color difference calculation unit 24 and the edit candidate point display control unit 25 perform the edit candidate point specifying process (step S7).

Here, the edit candidate point specifying process will be described with reference to the flowchart of FIG.
First, the color difference calculation unit 24 uses the hues of single colors of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M) and the adjacent ones of these single colors. Among the hues corresponding to the midpoints of the matching colors, any one of the hues for which the calculation of the maximum hue difference has not yet been completed is set as the hue to be processed (step S41).

  Next, the color difference calculation unit 24 specifies the color value m having the highest saturation in the color gamut constituted by the color gamut solid information of the second color gamut for the hue to be processed (step S42). Further, the color difference calculation unit 24 specifies the color value n having the highest saturation in the color gamut configured by the color gamut solid information of the first color gamut for the hue to be processed (step S43). Then, the color difference calculation unit 24 calculates the difference (color difference d) between the color value m and the color value n and sets it as the maximum color difference of the hue (step S44).

Next, the color difference calculation unit 24 determines whether or not the maximum color difference of hues has been calculated for all hues (step S45). Here, when the maximum color difference of the hue has not been calculated for all the hues (step S45: NO), the color difference calculation unit 24 proceeds to step S41.
On the other hand, when the maximum hue difference is calculated for all hues in step S45 (step S45: YES), the edit candidate point display control unit 25 selects the color difference among the calculated maximum hue differences for each hue. The color value m in a predetermined number of hues where d is larger is set as an edit candidate point, the edit candidate point is displayed on the color conversion table edit screen (step S46), and the process is terminated.

  After the edit candidate point specifying process, the edit point input unit 26 determines whether or not an edit candidate point has been selected by a user input operation (step S8). Here, when an edit candidate point is selected (step S8: YES), the edit point input unit 26 acquires the color value of the selected edit candidate point (step S9). On the other hand, if the setting for displaying the edit candidate point is not made in step S6 (step S6: NO), or if the edit candidate point is not selected in step S8 (step S8: NO), the edit point input unit 26 acquires the color value of the editing point in the second color gamut designated by the user's input operation (step S10).

Next, the edit amount input unit 27 sets a correction amount in accordance with a user input operation or the like on the color conversion table input screen (step S11). Further, the edit range input unit 28 sets a correction range in accordance with a user input operation or the like on the color conversion table input screen (step S12).
Next, the editing calculation unit 29 uses the color value (for example, set output device value) acquired by the editing point input unit 26, the correction amount set by the editing amount input unit 27, and the editing range input unit 28. A DP LUT corresponding to the edited color value is calculated using the set correction range (step S13).
Then, the storage unit 30 stores the DP of the second output device that reflects the DP LUT corresponding to the edited color value calculated by the editing operation unit 29 (step S14), and ends the process.

Next, the flow of the color conversion table editing process using DP and DLP will be described with reference to the flowchart of FIG. Here, processing similar to the flow of color conversion table editing processing using DP shown in FIG. 8 is assigned the same step number, and description thereof is omitted.
The computing unit 20 reads out a DLP to be edited (for example, a DLP for performing color conversion between another image forming apparatus (not shown) and the image forming apparatus 4) (step S51).

  Next, the arithmetic unit 20 reads the DP of the first output device that is a reference for color reproduction (step S2). Then, in the calculation unit 20, the first color gamut acquisition unit 21 performs display processing of the first color gamut (step S4).

After the display process of the first color gamut, the second color gamut acquisition unit 22 performs the display process of the second color gamut using the DLP (step S52).
Here, the display processing of the second color gamut using DLP will be described with reference to the flowchart of FIG. In addition, the same step number is attached | subjected about the process similar to the display process of the 2nd gamut shown in FIG. 10, and description is abbreviate | omitted.
The second color gamut acquisition unit 22 secures a memory area for storing data (color gamut solid information) constituting the color gamut solid of the second color gamut, and stores the color gamut solid information of the second color gamut. Initialization is performed (step S31).

  Next, the second color gamut acquisition unit 22 uses the DLP to convert the second output device model-dependent value (for example, CMYK) from the first output device model-dependent value (for example, the color value in the CMYK color space). A color value in the color space is calculated (step S61). After that, the second color gamut acquisition unit 22 uses the A2B LUT among the DPs of the second output device to calculate the model-independent value (for example, L * a) from the model-dependent value of the second output device. * B *) is calculated (step S34). The process flow from step S34 to step S38 is the same as the flow of the second color gamut display process shown in FIG. However, in the display process of the second color gamut using DLP, in step S37, model independent values are not calculated for all colors in the model-dependent values of the first output device (step S37: NO). The second color gamut acquisition unit 22 proceeds to step S61.

After the display process of the second color gamut using DLP, the calculation unit 20 determines whether or not the setting for displaying the candidate points is made (step S6). The flow of processing relating to steps S6 to S12 is the same as the flow of color conversion table editing processing using DP shown in FIG.
In the color conversion table editing process using DP and DLP, after the process of step S12, the editing calculation unit 29 acquires the color value (for example, the set output device value) and the editing amount acquired by the editing point input unit 26. Using the correction amount set by the input unit 27 and the correction range set by the edit range input unit 28, a DLP LUT corresponding to the edited color value is calculated (step S53). The storage unit 30 stores the DLP that reflects the edited color value calculated by the editing operation unit 29 (step S54), and ends the process.

  As described above, according to the color conversion table editing apparatus 10 of the present embodiment, the first color gamut acquisition unit 21 acquires the color gamut of the second output device as the first color gamut, and the second color gamut acquisition unit 22. However, the color gamut when the color output by the first output device is reproduced by the second output device is acquired as the second color gamut, and the color gamut display control unit 23 selects the first color gamut and the first color gamut. Since the difference between the two color gamuts is displayed as the difference between the two color gamuts, the difference between the first color gamut and the second color gamut can be clearly confirmed by the display content of the display unit 11. Further, the edit point input unit 26, the edit amount input unit 27, and the edit range input unit 28 accept input of adjustment for the second color gamut based on the displayed color gamut difference, and the edit calculation unit 29 The color gamut when the color output by the first output device is reproduced by the second output device using the color conversion table of the second output device is set to be the second color gamut after adjustment. Since the color conversion table of the second output device is edited, the user can easily adjust the second color gamut within the range of the first color gamut, that is, within the range of the color gamut of the second output device. The color gamut of the device that performs output after color reproduction, that is, the second output device that reproduces the color output by the first output device, can be fully utilized.

  Further, the editing candidate point display control unit 25 indicates candidate points (for example, editing candidate points Q1 to Q6, editing points) for indicating a difference between the first color gamut and the second color gamut based on a predetermined specific criterion. Display the limit points R1 to R6, etc., so that the display unit 11 can specifically display the difference between the first color gamut and the second color gamut, and when editing the second color gamut. The second color value to be edited and the color value included in the first color gamut to be edited can be specifically shown. That is, it is possible to provide information for more easily editing the second color gamut based on the candidate points.

  Further, the color difference calculating unit 24 determines the first color gamut and the above-described color based on the colors of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M). The edit candidate point display control unit 25 calculates a difference from the second color gamut, and the editing candidate point display control unit 25 is based on at least one of red, yellow, green, cyan, blue, and magenta among the calculated differences. Since the gamut difference is displayed as a candidate point, it is possible to more clearly indicate the color whose color reproduction result changes by editing the second gamut using the candidate point, and to the user the second gamut Thus, it is possible to provide the color conversion table editing apparatus 10 capable of more easily editing.

  Further, the edit point input unit 26 selects a candidate point according to the input content of the user performed via the operation input unit 12, and the adjustment amount of the second color gamut based on the selected candidate point is the edit amount. Since the input unit 27 determines, the second color gamut can be adjusted more specifically using the candidate points, and the second color gamut can be more easily edited by the user. The color conversion table editing device 10 can be provided.

  In addition, since the editing range input unit 28 designates the adjustment range of the second color gamut based on the predetermined adjustment range, the editing of the second color gamut is not limited to a specific color value, and may include a plurality of colors. To provide a color conversion table editing apparatus 10 that can adjust a color gamut for a range including a corresponding color gamut and can more easily edit a second color gamut for a user. Can do.

  The embodiment of the present invention should be considered that the embodiment disclosed this time is illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

(Modification)
FIG. 14 is a diagram illustrating a display example of the color conversion table editing screen in the modification. The same components as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 14, the edit candidate point display control unit 25 according to the modification displays a list L that preferentially shows candidate points having a larger difference between the first color gamut and the second color gamut.
The list L includes, for example, edit candidate points displayed in the color gamut view that have a larger difference (color difference d) between the color value n of the first color gamut and the color value m of the second color gamut. Display from top to bottom. A list L shown in FIG. 14 shows input points indicating input device values of respective edit candidate points, model-independent values corresponding to the input points (for example, values in the color space of the Sealab color system), and values of the color difference d. Although the numbers and numbers (Num) are assigned and displayed in descending order from the correspondence and the color difference d, they are merely examples and are not limited thereto.

Further, the editing range input unit 28 in the modification causes the display unit 11 to display the designated second color gamut adjustment range (correction range).
For example, as shown in FIG. 14, the edit range input unit 28 determines according to the color value of the selected edit candidate point and a predetermined correction range set according to the input operation on the color conversion table edit screen. A frame H3 indicating the outer periphery of the corrected range is displayed in the color gamut view of the color conversion table editing screen.

  As described above, according to the modified example, the edit candidate point display control unit 25 preferentially displays candidate points having a larger difference between the first color gamut and the second color gamut among the plurality of candidate points. Since it is displayed, the color value of the second color gamut having a larger room for editing can be specifically shown on the basis of the first color gamut, and the color of the second output device by editing the second color gamut Information can be provided to help the community fully utilize.

  In addition, since the editing range input unit 28 displays the adjustment range (correction range) of the designated second color gamut, the range of the color gamut in which the color changes by editing depending on the display content of the display unit 11 is clarified. It is possible to confirm information and to provide information for more easily editing the second color gamut.

Further, the color conversion table editing device acquires the color gamut of the first output device as the third color gamut, and displays the difference between the second color gamut and the third color gamut. Good.
Specifically, for example, a function for acquiring the color gamut of the first output device based on the color conversion table (for example, DP) of the first output device is provided in the arithmetic unit 20 and acquired by the function. The color gamut of the first output device is displayed in the color gamut view as the third color gamut. In this case, for example, as shown in FIGS. 7 and 14, the frame H4 indicating the third color gamut is displayed together with the frame H2 indicating the second color gamut, so that the second color gamut and the first color gamut are displayed. A difference from the color gamut of 3 will be shown. Here, not only the difference in display of the color gamut between the frames H2 and H4, but the same as the candidate points and lists for indicating the difference between the color value of the first color gamut and the color value of the second color gamut. With this mechanism, another candidate point or a list for indicating the difference between the color value of the second color gamut and the color value of the third color gamut may be displayed.

  By displaying the difference between the second color gamut and the third color gamut, the color gamut (second color gamut) when the color of the first output device is reproduced by the second output device is adjusted. In this case, not only the color gamut (first color gamut) of the second output device, but also the color gamut of the first output device (third color gamut) that is a reference for color reproduction is considered. Therefore, the color gamut can be edited while making full use of the color gamut of the second output device and the reproduction of the color of the first output device.

  In the above embodiment, all the hues are red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M). The single color is divided in units of 30 degrees based on the hue corresponding to the midpoint between adjacent colors, but this is an example, and the present invention is not limited to this. The angle value for separating the hue and the color reference can be arbitrarily set.

  In the above embodiment, a predetermined correction range (for example, “narrow”, “normal”, “wide”, etc.) is used, but the edit range input unit 28 determines the correction range. The correction range may be determined in accordance with an input operation by the user (for example, a numerical value for designating a range for adjusting the color gamut).

  Further, the color space of the model-dependent value and the color space of the model-independent value in the above embodiment are merely examples, and the present invention is not limited to this. For example, it should be handled as a profile such as color space by various color systems defined by the International Commission on Lighting (CIE), RGB, CMY and various color spaces based on these, YIQ, YCbCr, YPbPr, etc. Any color space can be used.

DESCRIPTION OF SYMBOLS 1 Color management system 4 Image forming apparatus 6 Colorimeter 10 Color conversion table editing apparatus 11 Display part 12 Operation input part 14 Command part 15 Measuring part 20 Calculation part 21 1st color gamut acquisition part 22 2nd color gamut acquisition part 23 Color Area display control unit 24 Color difference calculation unit 25 Edit candidate point display control unit 26 Edit point input unit 27 Edit amount input unit 28 Edit range input unit 29 Edit operation unit 30 Storage unit

Claims (8)

A color conversion table editing device for editing a color conversion table for reproducing a color output by a first output device by a second output device,
First acquisition means for acquiring a color gamut of the second output device as a first color gamut;
A color gamut obtained when the color output by the first output device is reproduced by the second output device using the color conversion table of the second output device is acquired as a second color gamut. Acquisition means;
Display means for displaying a difference between the first color gamut and the second color gamut as a color gamut difference;
Accepting means for accepting an input of adjustment for the second color gamut within a range of the color gamut difference displayed by the display means;
When the color output by the first output device is reproduced by the second output device using the color conversion table of the second output device based on the content of the input received by the receiving means Editing means for editing the color conversion table of the second output device so that the color gamut becomes the adjusted second color gamut;
A color conversion table editing apparatus comprising: Specifying means for specifying a candidate point for indicating a difference between the first color gamut and the second color gamut based on a predetermined specification criterion;
The color conversion table editing apparatus according to claim 1, wherein the display unit displays the candidate points. Calculation means for calculating a difference between the first color gamut and the second color gamut based on colors of red, yellow, green, cyan, blue and magenta;
The display means displays a difference in color gamut based on at least one of red, yellow, green, cyan, blue and magenta as a candidate point based on the difference calculated by the calculating means. 3. The color conversion table editing apparatus according to claim 2, wherein   The display means displays a list preferentially showing candidate points having a larger difference between the first color gamut and the second color gamut among the plurality of candidate points. The color conversion table editing apparatus according to 2 or 3. The accepting means is
Selecting means for selecting candidate points used for adjusting the second color gamut from among the plurality of candidate points;
Determining means for determining an adjustment amount of the second color gamut based on the candidate points selected by the selecting means;
5. The color conversion table editing apparatus according to claim 2, further comprising:   6. The color conversion table editing apparatus according to claim 1, further comprising designation means for designating an adjustment range of the second color gamut.   The color conversion table editing apparatus according to claim 6, wherein the display unit displays a range specified by the specifying unit. Third acquisition means for acquiring the color gamut of the first output device as a third color gamut;
The color conversion table editing apparatus according to claim 1, wherein the display unit displays a difference between the second color gamut and the third color gamut.

Images