JP2017073618A - Image processing device, image processing method, and image processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing device capable of presenting an adjustable patch to a user by generating the adjustable patch around an extracted color.SOLUTION: The image processing device causes a printer to print a chart including a patch of an adjustment color selected as an adjustment color being an adjustment object and a patch of a neighboring color having a color value that changes with respect to the adjustment color at a prescribed interval. A target color among colors of the patch on the printed chart is selected. A color conversion table to be used to convert a color to be printed by the printer is generated by using the adjustment color and the target color, and in the case that the patch of the neighboring color is not generated at a position adjacent to the patch of the adjustment color, a patch of the neighboring color is generated by changing the prescribed interval.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an image processing apparatus and an image processing method, and in particular, visually selects a target color from a printed chart and updates a color conversion table based on a signal value corresponding to the selected color. is there.

  In recent years, along with the improvement in performance of electrophotographic apparatuses, apparatuses that have achieved image quality equivalent to that of printing presses have appeared. For this reason, printing such as POPs used in sales stores can be performed more easily at each store. POP is an abbreviation for Point of purchase advertising, which is an advertisement for sales promotion. However, printing may be performed in a color different from that of the sample POP due to differences in printing apparatuses and printing timing. In this case, service personnel with specialized knowledge have been adjusting the color by adjusting the device in the past, but in recent years, sales representatives etc. can easily do even without special expertise A system for matching colors has been established. For example, a color to be adjusted is extracted from an image such as a POP, and a plurality of patches of a color near the extracted color are generated. Then, the chart in which the generated patches are arranged is printed, and the user selects a patch having a desired color from the printed patches. Then, there is a method of updating a table for performing color conversion in accordance with the color of the selected patch (see Patent Document 1).

  For example, there is a method of generating a patch in a hue direction with the extracted color as a center with respect to the extracted color when generating the patch. At this time, each patch is generated from the extracted color with a uniform color difference between a * and b *.

  Note that a * and b * are coordinate systems in the L * a * b * color space determined by the International Lighting Commission.

JP2011-114717A

  As described above, when a patch is generated with a uniform color difference centered on the extracted color, an adjustable patch may not be displayed depending on the position of the extracted color in the L * a * b * space and its sampling interval. is there. This makes it seem that there are no patches that can be adjusted even though the user has imagined the hue that he / she wants to adjust, so the opportunity for adjustment is lost.

  In order to solve the above problems, the image processing apparatus includes a first selection unit that selects an adjustment color to be adjusted, a patch of the adjustment color selected by the first selection unit, and a predetermined color for the adjustment color. Print control means for causing the printer to print a chart including a patch of a neighboring color having a color value that changes at an interval of the second, and a second color for selecting a target color from among the colors of the patches on the chart printed by the print control means The color used for converting the color printed by the printer using the selection means, the adjustment color selected by the first selection means, and the target color selected by the second selection means And generating a conversion table, and when the neighboring color patch is not generated at a position adjacent to the adjustment color patch, the predetermined color is changed to generate the neighboring color patch. Additional means, characterized by having a.

  In this image processing apparatus, the sampling interval is changed for a necessary region so that an adjustable patch is generated around the extracted color. Thus, if there is an area that can be adjusted, patches can be presented in all directions for the extracted color. Therefore, it is possible to prevent loss of adjustment opportunities due to the appearance that there are no patches that can be adjusted.

1 is a configuration diagram of an image forming system including an image processing apparatus according to the present invention. It is a block diagram which shows the physical structure in this invention. It is a block diagram which shows the module structure in this invention. It is a flowchart which shows the chart production | generation and color update process in 1st embodiment. It is a flowchart which shows the printing process in 1st embodiment. It is a flowchart which shows the chart production | generation process in 1st embodiment. It is a figure for Dist calculation in the 1st example. It is a figure which shows the chart data in this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

<First embodiment>
FIG. 1 is a system configuration diagram illustrating a configuration example of an image processing system including an image processing apparatus according to the first embodiment of the present invention. This image forming system includes a network 101, a computer 102, a display 103, and a printer 106. The printer 106 includes a printer controller 104 and a printer engine 105. The computer 102 and the printer 106 can communicate with each other via the network 101. For example, a print instruction can be transmitted from the computer 102 to the printer 106, and information about the printer 106 can be acquired by the computer 102. The computer 102 and the display 103 are connected to each other, and the computer 102 transmits screen information of the running application to the display 103 and outputs the screen. The printer controller 104 and the printer engine 105 are connected to each other, and the printer controller 104 transmits a control signal to the printer engine 105 to perform printer output.

  FIG. 2A is a block diagram illustrating a physical configuration of the computer 102. The computer 102 includes an internal bus 201, a CPU 202, a RAM 203, an external storage device 204, a display interface 205, an external input device 206, and a network interface 207. A CPU 202, a RAM 203, an external storage device 204, a display interface 205, an external input device 206, and a network interface 207 are connected to the network 101 and communicate data with the printer 106. When the computer 102 is activated, the CPU 202 reads an application execution program from the external storage device 204, stores it in the RAM 203, and executes the program. The program executed by the CPU 202 starts transmitting screen display data to the display interface 205 and outputs the screen to the display 103. In addition, the CPU 202 monitors user input information from the external input device 206, and when user input information is input, executes processing corresponding to the user input information defined in the program.

  FIG. 2B is a block diagram illustrating a physical configuration of the printer controller 104. The printer controller 104 includes an internal bus 208, a CPU 209, a RAM 210, an external storage device 211, a network interface 212, an engine interface 213, and an input device 214. The CPU 209, RAM 210, external storage device 211, network interface 212, engine interface 213, and input device 214 communicate data with each other via an internal bus 208. When the printer controller 104 is activated, the CPU 209 reads an execution program from the external storage device 211, stores it in the RAM 210, and executes the program.

  Each process such as determination and conditional branching described below is performed by each CPU according to the program, and data generated in the middle is temporarily stored in each RAM and reused in other processes.

  FIG. 3A is a block diagram illustrating a module configuration of a program executed by the CPU 202. A module of a program executed by the CPU 202 includes a data acquisition unit 301, a chart data generation unit 302, a print processing unit 303, and a color update processing unit 304. The data acquisition unit 301 acquires an adjustment color value (adjustment value) to be adjusted, table data necessary for chart generation, and a color conversion table. In the present embodiment, the adjustment value is a color space value used in a general monitor. The color space used in the monitor is, for example, an sRGB color space or an AdobeRGB color space. In this description, the adjustment value is a value in the sRGB color space. The color conversion table is a table for converting sRGB into a device-dependent RGB (devRGB) color space. This table shows the relationship between the color value of the color displayed on the display 103 and the color value of the color formed on the printer 106.

  Further, table data is required for the process of updating the color conversion table. This table data is a table for converting devRGB into L * a * b *. L * a * b * is a device-independent three-dimensional color space that takes into account human visual characteristics (visual equality). However, each color space is not limited to this. The chart data generation unit 302 generates chart data based on the data acquired by the data acquisition unit 301. The print processing unit 303 performs a print control process necessary for printing the chart data generated by the chart data generation unit 302 by the printer 106. Specifically, the chart data is converted into a color space that can be handled by the printer 106 and transmitted to a rendering processing unit 305 described later. The color update processing unit 304 acquires a target color value (target value), and updates the color conversion table using the acquired target value, the adjustment value acquired by the data acquisition unit 301, and the color conversion table. Do.

  FIG. 3B is a block diagram illustrating a module configuration of a program executed by the CPU 209. A module of a program executed by the CPU 209 includes a rendering processing unit 305, a color conversion unit 306, a binarization processing unit 307, and an engine control unit 308. A rendering processing unit 305 renders image data such as chart data converted by the print processing unit 303 in an image memory (not shown). The color conversion unit 306 converts the image data drawn in the image memory into image data (CMYK) corresponding to the color material handled by the printer engine 105. The binarization processing unit 307 performs image formation processing such as screen processing and error diffusion processing on the image data converted by the color conversion unit 306, converts the image data into binary image data, and outputs the binary image data to the engine control unit 308. The engine control unit 308 outputs a printer engine control command to the engine interface 213 based on the binary image data converted by the binarization processing unit 307. As a result, the printer engine 105 forms an image on the paper surface as an ink image or a toner image.

  Next, processing for selecting a target color visually from the printed chart using FIG. 4 and updating the color conversion table based on the corresponding target value will be described. In the processing of FIG. 4, steps S401, S402, and S404 to S406 are performed by the CPU 202 of the computer 102, and step S403 is performed by the CPU 209 of the printer controller 104.

  First, in step S401, the data acquisition unit 301 acquires an adjustment color value (adjustment value) to be adjusted, table data necessary for generating chart data, and a color conversion table. The adjustment value acquisition method may be a method in which sRGB combinations corresponding to several colors are prepared in advance, and the user selects an arbitrary color combination (sRGB combination) from the combinations. Alternatively, a method may be provided in which a user can input an sRGB * value corresponding to the adjustment color. Further, when there is image data whose color is to be changed, such as POP, a method may be used in which the sRGB * value corresponding to the adjustment color is acquired from the image data and used as the adjustment value. For example, the color (adjustment color) that the user wants to change is pointed out from the image data, and the sRGB * value of the indicated color is automatically acquired, and this may be used as the adjustment value.

  The color conversion table is held in the external storage devices 204 and 211 of the computer 102 or the printer 106, and is a color conversion table used when printing image data. A table necessary for generating chart data is selected from tables prepared in advance for converting from devRGB to L * a * b * corresponding to the type of printer. To create a table for converting from devRGB to L * a * b * according to the type of printer, for example, a chart dedicated to table creation is printed by the corresponding printer. Then, the L * a * b * value is acquired by measuring the printed chart, and the devRGB * value is associated with the acquired L * a * b * value.

  Subsequently, the chart data generation unit 302 generates chart data based on the data acquired in step S401 in step S402. Details of the chart data generation will be described later.

  In step S403, the print processing unit 303 prints the chart based on the chart data generated in step S402. Details of the printing process will be described later.

  The color update processing unit 304 performs steps S404 to S406. First, in step S404, the user selects a target color patch from the chart printed in step S403, and receives the selection result to obtain a target value corresponding to the color. For example, a chart image printed using the chart data (sRGB) generated in step S <b> 402 is displayed on the display 103. The displayed chart image and the printed chart have the same patch arrangement. Then, the user selects, from the chart displayed on the display 103, a patch at the same position as the position of the patch to be selected as the target color from the patches on the printed chart. Thereby, a target value corresponding to the adjustment value is obtained. Alternatively, the coordinate position of each patch may be added to the chart when the chart is printed, and the coordinate position of the selected patch may be input. In this case, the displayed chart image and the printed chart may not necessarily have the same patch arrangement.

  In step S405, color update processing is performed using the adjustment value acquired in step S401, the color conversion table, and the target value acquired in step S404. The color update process corresponds to the color conversion table so that the output value when the adjustment value is converted using the color conversion table becomes the same value as the output value when the target value is converted using the color conversion table. Update the part. For example, it is assumed that the sRGB * value of the adjustment value is (150, 0, 0) and the devRGB * value of the output value after color conversion is (120, 0, 0). Then, it is assumed that the sRGB * value of the target value is (150, 20, 0), and the devRGB * value of the output value after color conversion is (120, 15, 0). In this case, sRGB (arbitrary color) so that the output value of the sRGB * value (150, 0, 0) of the adjustment value becomes the devRGB * value (120, 15, 0) of the output value after the color conversion of the target value. Space) → devRGB (device dependent color space) color conversion table is updated. Further, depending on the target value, there may be a color collapse or gradation step in the updated color conversion table. Therefore, it is desirable to perform the smoothing process on the colors near the updated part of the color conversion table.

  Finally, in step S406, the color conversion table updated in step S405 is stored in the external storage devices 204 and 211 of the computer 102 or printer 106. Saving may be performed by overwriting the color conversion table acquired in step S401, or may be saved as another color conversion table.

  Next, details of the chart data generation processing in step S402 will be described with reference to FIG. As described above, all processing in FIG. 6 is performed by the chart data generation unit 302.

  In step S601, the adjustment value acquired in step S401 is acquired. In step S602, the color conversion table acquired in step S401 and the table data necessary for generating chart data are acquired.

  In step S603, a table (sRGB → L * a * b * conversion table) for converting adjustment values and target values into L * a * b * values is generated. The sRGB → L * a * b * conversion table is a combination of the color conversion table (sRGB → devRGB conversion table) acquired in step S602 and the table necessary for chart data generation (devRGB → L * a * b * conversion table). To generate. The synthesis is performed using, for example, an interpolation calculation. In the interpolation calculation, when a value not defined in the calculation table is input, interpolation is performed using a value defined in the calculation table close to the input value. An interpolation calculation method is called tetrahedral interpolation. In tetrahedral interpolation, interpolation calculation is performed using values defined in four calculation tables close to input values. In this process, sRGB → L * a * b is calculated by performing the tetrahedral interpolation calculation using the input as the devRGB * value of the sRGB → devRGB conversion table and the calculation table as the devRGB → L * a * b * conversion table. * Generate a conversion table. In the present embodiment, tetrahedral interpolation is used for synthesis, but the present invention is not limited to this. From the sRGB → devRGB conversion table and the devRGB → L * a * b * conversion table to the sRGB → L * a * b * conversion table. Any method may be used as long as can be generated.

  In step S604, the adjustment value is converted into an L * a * b * value. In the conversion, the sRGB * value of the adjustment value is converted into L * a * b * using the sRGB → L * a * b * conversion table generated in step S603. The conversion is executed by performing tetrahedral interpolation with the input as the adjustment value and the calculation table as the sRGB → L * a * b * conversion table.

In step S605, based on the L * a * b * value of the adjustment value generated in step S604, an L * a * b * value for generating a patch (candidate patch) that is a candidate for selecting a target value. Is generated. When developing on the hue plane, the L * a * b * value of the candidate patch is generated step by step with the L * value, a * value, and b * value centered on the L * a * b * value of the adjustment value. This is done by combining the converted values. The following formula 1 is used to generate each of the L * value, a * value, and b * value.
[Formula 1]
Li = Lb
ai = ab + i × Dist
bi = bb + i × Dist
(-N ≦ i ≦ n)
Lb, ab, and bb are L * a * b * values of adjustment values, i is a value that changes stepwise according to the number of candidate patches to be generated (integer value), and Dist is L * a * b between candidate patches. * Indicates the interval in the color space. For example, assume that the L * a * b * value of the adjustment value is (50, 0, 0), Dist is 1, and a 7 × 7 patch is generated on the ab plane. In this case, i becomes -3, -2, -1, 0, 1, 2, 3. Therefore, ai is -3, -2, -1, 0, 1, 2, 3, and bi is -3, -2, -1, 0, 1, 2, 3, and so on. All these values are combined to generate 49 candidate patch L * a * b * values. These candidate patches L * a * b * values take values in the vicinity of the L * a * b * values of the adjustment values, and the colors of the candidate patches are expressed by colors near the adjustment colors. Hereinafter, a patch of a neighboring color is referred to as a candidate patch. A method for determining Dist will be described later. Processing for excluding candidate patches that are out of the color reproduction range of the printer for the neighboring colors generated by the above processing is performed. Candidate patches are generated in an L * a * b * color space, that is, a device-independent color space, and thus candidate patches outside the color reproduction range of the printer may be generated. Candidate patches outside the color reproduction range of the printer are rounded to a color range that can be reproduced by the printer, and therefore the corresponding patches are excluded in this embodiment. As a method for performing the process of excluding candidate patches, any method may be used as long as candidate patches determined to be out of the color reproduction range cannot be selected as target values. Further, whether or not it is out of the color reproduction range is determined based on each candidate patch in the range of each L * a * b * value of the devRGB → L * a * b * conversion table acquired in step S602. Judgment is made based on whether or not L * a * b * values are included. The determination is a tetrahedron in the L * a * b * color space consisting of an arbitrary L * a * b * value in the devRGB → L * a * b * conversion table and three L * a * b * values in the vicinity thereof. Is determined by determining whether the L * a * b * value of the candidate batch exists. For all tetrahedrons that can be formed with L * a * b * values in the devRGB → L * a * b * conversion table, it is determined whether or not candidate patches exist, and they exist in all tetrahedrons. If it is determined that it is not, the candidate patch is determined to be outside the color reproduction range.

  In this embodiment, the determination is performed using a tetrahedron that can be formed from the devRGB → L * a * b * conversion table. However, the color reproduction range of the printer is extracted, and the candidate patches are color-reproduced. Any method may be used as long as it can be determined whether the value is out of range.

Here, the Dist determination method will be described with reference to FIG. A color reproduction range 701 is a color reproduction range of the image processing apparatus in which the table data necessary for generating the chart data acquired in step S602 is projected on the ab plane. Each line segment WY, WR, WM, WB, WC, WG is a primary line connecting the white color W to each of the primary colors yellow Y, red R, magenta M, blue B, cyan C, green G. First, the shortest length of each primary line is determined as a reference line segment. In FIG. 7, WB is the reference line. A line segment connecting the adjustment value 702 acquired in step S601 and the white point W to the end of the color gamut is defined as WT. The Dist in the hue of the reference line segment is Dist_B, and the Dist in the WT hue is Dist_T. Using these, Dist_T is obtained.
[Formula 2]
Reference line segment: WT = Dist_B: Dist_T
(For example, Dist_B = 1)
Note that the value of Dist_B does not have to be unique and may take any value.

  As shown in FIG. 7, the color reproduction of the image processing apparatus varies depending on the hue. Therefore, if the same Dist is used for all hues when generating a candidate patch, there is a difference in the degree of patch division for each hue. As described above, by calculating Dist_T according to the hue where the adjustment value is located and calculating it according to Equation 1, the difference in the degree of patch division for each hue can be reduced.

  FIG. 8 shows an example of patch data. FIG. 8A shows an example of patch data 801 generated by the processing up to step S605. At this time, Dist = 6.

  The patch data 801 is developed in a 7 × 7 patch area with the adjustment value 802 as the center. Among these, the white patch indicates that it is out of the color reproduction range. When the patch data 801 is viewed at a glance, since the patches 803 and 804 adjacent to the adjustment value 802 are white, it seems that the color cannot be adjusted in the hue direction, so the user has imagined the hue to be adjusted. Nevertheless, the opportunity for adjustment may be lost.

  In step S606, it is determined whether or not the eight patches adjacent to the adjustment value 802 are outside the color reproduction range.

  If it is determined in step S606 that the adjacent patch having the adjustment value 802 is out of the color reproduction range, it is determined in step S607 whether or not Dist is less than the minimum value that can be set.

  If Dist is larger than the minimum value in step S607, Dist is reduced in step S608, and patch data is generated by the same processing as in step S605.

  In step S609, it is determined whether patches 803 and 804 adjacent to the adjustment value 802 are within the color reproduction range. For example, the patch data generated in step S605 and the patch data generated in step S608 are compared at least with respect to the presence or absence of a patch outside the color reproduction range. As a result, it is possible to observe changes in the color reproduction range 803 and 804 adjacent to the adjustment value 802 by reducing Dist. When a difference occurs between the patches 803 and 804, L * a * b * values within the color reproduction range are stored.

  If the patches 803 and 804 adjacent to the adjustment value 802 are within the color reproduction range in step S609, the patches that are within the color reproduction range are added to the patch data generated in step S605 in step S610, and step S606 is performed. Return to.

  If the patches 803 and 804 adjacent to the adjustment value 802 are not within the color reproduction range in step S609, the process returns to step S606.

  If it is determined in step S606 that the adjacent patch having the adjustment value 802 is not out of the color reproduction range, and if Dist is less than the minimum value in step S607, the process proceeds to step S611.

  In step S611, candidate patches generated and arranged with L * a * b * values are converted into sRGB * values. Conversion from L * a * b * values to sRGB * values is performed by signal search processing using the sRGB → L * a * b * conversion table generated in step S603. In the signal search process, first, all combinations of signal values from 0 to 255 of sRGB * values are input, and tetrahedral interpolation is performed using the sRGB → L * a * b * conversion table as a calculation table. Among all L * a * b * values calculated by tetrahedral interpolation, the L * a * b * value closest to the L * a * b * value of any candidate patch is extracted. Then, the sRGB * value corresponding to the extracted L * a * b * value is set as the sRGB * value of the candidate patch. By performing this signal search process on all candidate patches, the candidate patches generated and arranged with L * a * b * values are converted into sRGB * values. In this embodiment, the signal search process is used. However, the present invention is not limited to this. For example, an inverse table of the sRGB → L * a * b * conversion table (L * a * b * → sRGB conversion table) is created. The L * a * b * values of the candidate patches may be converted into sRGB * values.

  Finally, in step S612, the sRGB * value candidate patches generated in step S611 are transmitted to the print processing unit 303 as one chart.

  Next, details of the chart printing process in step S403 will be described with reference to FIG. First, the chart data generation unit 302 performs color conversion on the chart data generated in step S402 using the color conversion table acquired in step S401 in step S501. That is, the chart data is converted from sRGB to devRGB color space. Then, the color-converted chart data is transmitted to the rendering processing unit 305. In step S502, the rendering processing unit 305 renders the image memory according to the chart data received from the chart data generation unit 302. The rendering processing unit 305 sends the image data drawn in the image memory to the color conversion unit 306. In step S <b> 503, the color conversion unit 306 converts the image data into CMYK data using the LUT for converting from devRGB to CMYK stored in advance in the external storage device 211, and sends the data to the binarization processing unit 307. In step S504, the binarization processing unit 307 converts the received chart data after color conversion into binary image data by performing image forming processing such as screen processing and error diffusion processing, and outputs the binary image data to the engine control unit 308. . In step S505, the engine control unit 308 outputs a printer engine control command to the engine interface 213 based on the binary image data converted in step S504. As a result, the printer engine 105 forms a chart in which candidate patches are printed on the paper surface as ink images or toner images. A color conversion table in which the user visually selects a patch having a desired color from the patches arranged in the printed chart, and uses the selected patch color as a target color, and the adjustment color is the target color. Is generated.

  An example of chart data generated by performing the above processing will be described with reference to FIG. FIG. 8A is generated by step S605 as described above. At this time, Dist = 6 and the minimum value of Dist is 1. In FIG. 8A, the patch 803 and the patch 804 are out of the color reproduction range, and thus are white patches. FIG. 8B shows an example of a result obtained by performing the processing from step S606 to step S610. That is, chart data is generated with Dist = 5.

  Comparing FIG. 8B and FIG. 8A, it can be determined that the patch 803 is within the color reproduction range. The patch 804 is processed once again to obtain FIG. 8C. Therefore, since it can be determined that the patch 803 is within the color reproduction range by setting Dist = 5 and the patch 804 is within the color reproduction range by setting Dist = 4, the L * a * b * values of the patch 804 are shown in FIG. Add to the chart data.

  Even if Dist ≦ minimum value, if the adjustment value 802 is outside the color reproduction range, it means that the adjustment value exists at the end of the color gamut, and therefore the chart generated in step S605. Data will be used.

  As described above, when a user visually selects a desired color (target color) from the printed chart, an adjustable patch is generated around the extracted color. Changes the sampling interval that originally had a predetermined interval. Thus, if there is an area that can be adjusted, patches can be presented in all directions with respect to the extracted color, so that it is possible to prevent loss of adjustment opportunities due to the fact that there is no patch that can be adjusted.

  Note that the processing other than the chart printing (step S403) of the present embodiment has been described as a configuration in which the computer 102 in FIG. 1 performs, but these processing may be performed only by the printer controller 104.

<Second Embodiment>
In step S607 of the first embodiment, processing can be performed until Dist reaches a minimum value that can be calculated. However, it may be difficult for the user to select a color even if the resolution is smaller than the color difference that can be recognized by humans.

  Therefore, the determination in step S607 is set to Dist ≦ threshold. This threshold may be set to a color difference that can be recognized by humans. For example, in the JIS standard, it is said that the level of color separation comparison is hardly noticed when ΔE ≦ 3.2, which is the distance between colors of the L * a * b * color system. Therefore, the threshold value may be set as ΔE3.2. Further, a value using a CIE2000 color difference expression that can produce a result close to human visual characteristics may be used, and the present invention is not limited to this.

  By doing as described above, the user can surely recognize the color difference between the patches on the printed chart, so that the color can be easily selected.

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

Claims (10)

First selection means for selecting an adjustment color to be adjusted;
A print control unit that causes a printer to print a chart including a patch of the adjustment color selected by the first selection unit and a patch of a neighboring color having a color value that changes at a predetermined interval with respect to the adjustment color;
Second selection means for selecting a target color among the colors of the patches on the chart printed by the print control means;
Using the adjustment color selected by the first selection unit and the target color selected by the second selection unit, a color conversion table used for converting the color printed by the printer is generated. Generating means,
When the neighboring color patch is not generated at a position adjacent to the adjustment color patch,
Changing means for changing the predetermined interval to generate the patch of the neighboring color;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein the first selection unit selects a color selected by a user as the adjustment color.   The image processing apparatus according to claim 1, wherein the second selection unit selects a color corresponding to a patch selected by a user from among patches on the chart as the target color.   2. The patch is printed by the printer after the adjustment color selected by the first selection means and a color adjacent to the adjustment color are converted to colors in an L * a * b * color space. The image processing apparatus according to 1.   The image processing apparatus according to claim 1, wherein the arrangement of the patches in the chart is such that the patch of the adjustment color surrounds the patch of the adjustment color.   The image processing apparatus according to claim 1, wherein the printer includes an image forming apparatus connected to the image processing apparatus.   The image processing apparatus according to claim 1, wherein when the predetermined interval is changed by the changing unit, control is performed so that the predetermined interval does not become smaller than a threshold value.   The image processing apparatus according to claim 1, wherein the predetermined interval is determined by a hue. A first selection step of selecting an adjustment color to be adjusted;
A print control step for causing a printer to print a chart including the patch of the adjustment color selected in the first selection step and a patch of a neighboring color having a color value that changes at a predetermined interval with respect to the adjustment color;
A second selection step of selecting a target color from among the colors of the patches on the chart printed in the print control step;
A color conversion table used for converting a color printed by the printer using the adjustment color selected in the first selection step and the target color selected in the second selection step. Generating step to generate,
When the neighboring color patch is not generated at a position adjacent to the adjustment color patch,
A changing step of changing the predetermined interval to generate the patch of the neighboring color;
An image processing method comprising:   A program for causing a computer to execute the image processing method according to claim 9.

Images