JP5857860B2 - Color adjustment apparatus, color adjustment method, color adjustment program, and medium storing color adjustment program - Google Patents

Description

  The present invention relates to a color adjustment device, a color adjustment method, a color adjustment program, and a medium storing a color adjustment program.

  Conventionally, an output color of a color printer is adjusted to a desired color by a color management system using a device profile.

In such a color management system, a device such as an L ^* a ^* b ^* color system or an XYZ color system from RGB values / CMYK values in a device-dependent color space such as an RGB color system or a CMYK color system. Color conversion is performed using a source profile for conversion to color system values in an independent color space, and a destination profile for conversion to CMYK values for a color printer that outputs from color space data. It has been broken.

  After such color conversion, UCR (Under Color Removal) or GCR (Gray Component Replacement) processing for replacing the CMY color material with the K plate, processing for limiting the total value of CMYK, and the like are performed. Color adjustment is performed to save color materials while maintaining color reproducibility.

  In addition, for the purpose of color material cost management or the like, there is one that calculates the color material (toner) consumption amount in accordance with the print contents of the print job and predicts the color material consumption amount in advance (for example, , Patent Document 1)

JP 2008-123166 A

  However, when saving the color material as described above, the saving amount is determined in consideration of color reproducibility, and therefore differs for each image to be printed. Technology cannot accurately estimate the color material savings.

  An object of the present invention is to provide a color adjustment device, a color adjustment method, a color adjustment program, and a color adjustment program that can accurately estimate the amount of color material saved when color material is saved while maintaining color reproducibility. To provide a stored medium.

In order to solve the above-described problem, the invention according to claim 1 is a color adjustment apparatus,
A normal CMYK value is acquired from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value is greater than the normal CMYK value of the input image data. Control for obtaining a reduced saved CMYK value, obtaining a reduction amount of the saved CMYK value with respect to the normal CMYK value based on the obtained normal CMYK value and the saved CMYK value, and recognizing the reduction amount in a recognizable manner. With a control unit to perform ,
The control unit outputs from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. Each of the color values is obtained, a color difference that is a difference between the output color value obtained from the normal CMYK value and the output color value obtained from the saved CMYK value is obtained, and control for notifying the color difference is performed . Features.

According to a second aspect of the present invention, in the color adjustment apparatus according to the first aspect,
The control unit selects one of the acquired normal CMYK value and the saved CMYK value, and performs control to form an image on a sheet based on the selected CMYK value.

According to a third aspect of the present invention, in the color adjustment apparatus,
A normal CMYK value is acquired from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value rather than the normal CMYK value of the input image data Obtains the saved CMYK value with reduced, forms an image on the paper based on the obtained saved CMYK value, obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value, and informs the reduction amount so that it can be recognized A control unit for performing control ,
The control unit outputs from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. Each of the color values is obtained, a color difference that is a difference between the output color value obtained from the normal CMYK value and the output color value obtained from the saved CMYK value is obtained, and control for notifying the color difference is performed . Features.

According to a fourth aspect of the present invention, in the color adjustment apparatus according to the second or third aspect,
The control unit performs control to form an image on a sheet at a first resolution, and obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value at a second resolution lower than the first resolution. Features.

The invention according to claim 5 is the color adjustment apparatus according to any one of claims 1 to 4,
The control unit represents a reduction amount of the saving CMYK value with respect to the normal CMYK value by a reduction rate of the CMYK value with respect to the normal CMYK value.

The invention according to claim 6 is the color adjustment apparatus according to any one of claims 1 to 5,
The control unit obtains a reduction amount of the saving CMYK value with respect to the normal CMYK value after multiplying each value of the saving CMYK value by a predetermined coefficient.

The invention according to claim 7 is the color adjustment apparatus according to any one of claims 1 to 6,
The control unit inputs job data including a plurality of pages, selects a page for which a reduction amount is to be obtained from the plurality of pages of the job data, and reduces the saved CMYK value with respect to the normal CMYK value for the selected page. It is characterized by determining the quantity.

The invention according to claim 8 is the color adjustment apparatus according to any one of claims 1 to 7 ,
The control unit performs control for obtaining a color difference for each pixel of the input image data and notifying the average of the color difference for each pixel so as to be recognized.

The invention according to claim 9 is the color adjustment apparatus according to any one of claims 1 to 7 ,
The control unit performs control for obtaining a color difference for each pixel of the input image data, and notifying the maximum of the color differences obtained for each pixel in a recognizable manner.

The invention according to claim 10 is a color adjustment method,
A normal CMYK value acquisition step of acquiring normal CMYK values from input image data using a color conversion table for converting input image data into CMYK values of an output device;
A saving CMYK value acquisition step of acquiring a saving CMYK value in which a ratio of the CMY value to the CMYK value is smaller than the normal CMYK value of the input image data;
A reduction amount acquisition step for obtaining a reduction amount of the saving CMYK value with respect to the normal CMYK value based on the normal CMYK value and the saving CMYK value acquired in the normal CMYK value acquisition step and the saving CMYK value acquisition step;
A notification step of recognizing the reduction amount obtained in the reduction amount acquisition step in a recognizable manner;
An output color value is obtained from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. A color difference notification step of obtaining a color difference that is a difference between an output color value obtained from the normal CMYK value and an output color value obtained from the saved CMYK value, and recognizing the color difference in a recognizable manner;
It is characterized by including.

The invention according to claim 11 is the color adjustment method according to claim 10 ,
An image forming step of selecting one of the normal CMYK value and the saved CMYK value acquired in the normal CMYK value acquisition step and the saving CMYK value acquisition step, and forming an image on a sheet based on the selected CMYK value It is characterized by including.

The invention according to claim 12 is a color adjustment method,
A normal CMYK value acquisition step of acquiring normal CMYK values from input image data using a color conversion table for converting input image data into CMYK values of an output device;
A saving CMYK value acquisition step of acquiring a saving CMYK value in which a ratio of the CMY value to the CMYK value is smaller than the normal CMYK value of the input image data;
An image forming step of forming an image on a sheet based on the saved CMYK value acquired in the saved CMYK value acquisition step;
A reduction amount acquisition step for obtaining a reduction amount of the saving CMYK value with respect to the normal CMYK value based on the normal CMYK value and the saving CMYK value acquired in the normal CMYK value acquisition step and the saving CMYK value acquisition step;
A notification step of recognizing the reduction amount obtained in the reduction amount acquisition step in a recognizable manner;
An output color value is obtained from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. A color difference notification step of obtaining a color difference that is a difference between an output color value obtained from the normal CMYK value and an output color value obtained from the saved CMYK value, and recognizing the color difference in a recognizable manner;
A color adjustment method comprising:

The invention according to claim 13 is the color adjustment method according to claim 11 or 12 ,
In the image forming step, control is performed to form an image on the paper at the first resolution,
In the reduction amount acquisition step, a reduction amount of the saved CMYK value with respect to the normal CMYK value is obtained with a second resolution lower than the first resolution.

The invention according to claim 14 is the color adjustment method according to any one of claims 10 to 13 ,
In the notifying step, a reduction amount of the saved CMYK value with respect to the normal CMYK value is represented by a reduction rate of the CMYK value with respect to the normal CMYK value.

The invention according to claim 15 is the color adjustment method according to any one of claims 10 to 14 ,
In the reduction amount obtaining step, the reduction amount of the saving CMYK value with respect to the normal CMYK value is obtained after multiplying each value of the saving CMYK value by a predetermined coefficient.

The invention according to claim 16 is the color adjustment method according to any one of claims 10 to 15 ,
A page selection step of inputting job data consisting of a plurality of pages and selecting a page for which a reduction amount is to be calculated from the plurality of pages of the job data,
In the reduction amount acquisition step, a reduction amount of the saving CMYK value with respect to the normal CMYK value for the page selected in the page selection step is obtained.

The invention according to claim 17 is the color adjustment method according to any one of claims 10 to 16 , wherein
In the color difference notification step, a color difference is obtained for each pixel of the input image data, and an average of the color difference for each pixel is reported so as to be recognizable.

The invention according to claim 18 is the color adjustment method according to any one of claims 10 to 16 ,
In the color difference notification step, a color difference is obtained for each pixel of the input image data, and a maximum one of the color differences obtained for each pixel is notified so as to be recognized.

The invention according to claim 19 is a color adjustment program,
Computer
A normal CMYK value is acquired from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value is greater than the normal CMYK value of the input image data. Control for obtaining a reduced saved CMYK value, obtaining a reduction amount of the saved CMYK value with respect to the normal CMYK value based on the obtained normal CMYK value and the saved CMYK value, and recognizing the reduction amount in a recognizable manner. There line,
Further, an output color value is obtained from the normal CMYK value and the saved CMYK value by using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. respectively obtained, the normal determined color difference is a difference between the output color value obtained from the savings CMYK value and the output color value obtained from the CMYK values, function control of recognizably notifying the color difference as a line intends control means Let

The invention described in claim 20 is the color adjustment program according to claim 19 ,
The control unit selects one of the acquired normal CMYK value and the saved CMYK value, and performs control to form an image on a sheet based on the selected CMYK value.

The invention according to claim 21 is a color adjustment program,
Computer
A normal CMYK value is obtained from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value relative to the normal CMYK value of the input image data. Is obtained, and an image is formed on the sheet based on the obtained saved CMYK value, a reduction amount of the saved CMYK value with respect to the normal CMYK value is obtained, and the reduction amount is recognizable and notified. control stomach line,
Further, an output color value is obtained from the normal CMYK value and the saved CMYK value by using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. respectively obtained, the normal determined color difference is a difference between the output color value obtained from the savings CMYK value and the output color value obtained from the CMYK values, function control of recognizably notifying the color difference as a line intends control means Let

The invention according to claim 22 is the color adjustment program according to claim 20 or 21 ,
The control means performs control to form an image on a sheet at a first resolution, and obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value at a second resolution lower than the first resolution.

The invention according to claim 23 is the color adjustment program according to any one of claims 19 to 22 ,
The control means represents a reduction amount of the saved CMYK value with respect to the normal CMYK value by a reduction rate of the CMYK value with respect to the normal CMYK value.

According to a twenty-fourth aspect of the present invention, in the color adjustment program according to any one of the nineteenth to twenty- third aspects,
The control means obtains a reduction amount of the saving CMYK value with respect to the normal CMYK value after multiplying each value of the saving CMYK value by a predetermined coefficient.

The invention according to claim 25 is the color adjustment program according to any one of claims 19 to 24 , wherein:
The control means inputs job data consisting of a plurality of pages, selects a page for which a reduction amount is to be obtained from the plurality of pages of the job data, and reduces the saved CMYK value with respect to the normal CMYK value for the selected page Find the amount.

The invention according to claim 26 is the color adjustment program according to any one of claims 19 to 25 ,
The control means performs a control for obtaining a color difference for each pixel of the input image data and notifying the average of the color difference for each pixel so as to be recognized.

The invention according to claim 27 is the color adjustment program according to any one of claims 19 to 25, wherein:
The control means performs control for obtaining a color difference for each pixel of the input image data and notifying the maximum of the color differences obtained for each pixel.

The invention according to claim 28 is a computer-readable medium,
A color adjustment program according to any one of claims 19 to 27 is stored.

  According to the present invention, when the color material is saved while maintaining the color reproducibility, the saved amount of the color material can be accurately estimated.

1 is a system configuration diagram of a color adjustment system according to the present embodiment. It is a block diagram which shows the functional structure of client PC. It is explanatory drawing of a 1st LUT. It is a schematic diagram showing a color chart. FIG. 5 is a schematic diagram showing a state where a color patch of K: 0% is arranged in the color chart of FIG. 4. It is a figure which shows the distribution of the sample point on the locus | trajectory by the value of CMY, and the value of a color system, and the point which performs an interpolation process. It is the figure which showed the order of the interpolation process about the combination of the value of CMY. It is a figure showing the one-dimensional LUT which converts each value of CMYK. It is explanatory drawing of a 2nd LUT. It is a figure which shows target value T 'in an a ^* L ^* coordinate system. It is a figure which shows the target value T in CM coordinate system. It is the figure which expanded the area | region V0 shown in FIG. FIG. 13 is a diagram illustrating a region V0 ′ corresponding to the region V0 illustrated in FIG. 12 in the a ^* L ^* coordinate system. It is a figure explaining color gamut mapping. It is a flowchart explaining the production | generation procedure of a device link profile. It is a flowchart explaining a color adjustment table creation process. It is a figure explaining a K version production | generation curve. It is explanatory drawing of a 3rd LUT. It is a flowchart explaining a total amount restriction | limiting setting process. It is a figure explaining the change of a color gamut. It is a flowchart explaining a color conversion process. It is a flowchart explaining a saving mode selection process. It is a flowchart explaining the device link profile production | generation process for saving modes. It is a flowchart explaining a coloring material saving amount estimation process. It is a figure explaining the setting screen for estimating savings. It is a flowchart explaining a color material saving amount notification process. It is a figure explaining the setting screen for performing the notification of a saving result.

  Hereinafter, a color adjustment system according to an embodiment of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In addition, in the following description, what has the same function and structure attaches | subjects the same code | symbol, and abbreviate | omits the description.

  Further, in the embodiment of the present invention, the entire color adjustment system is referred to as a color adjustment system as a whole, but a part or all of the devices constituting the color adjustment system can of course be referred to as a color adjustment apparatus. It is.

  FIG. 1 shows an example of the configuration of a color adjustment system 1000 according to the present invention. The color adjustment system 1000 includes, for example, a color printer 1, a controller 2, a measuring device 3, and a client PC (Personal Computer) 10. The color adjustment system 1000 adjusts the color of image data output from a device (target device) that is a target of color adjustment, and reproduces the color of the image data with the color printer 1 (destination device). In the following description, the target device is assumed to be a color monitor device that outputs RGB color image data.

  The color printer 1 outputs a CMYK image composed of three basic colors of CMY (cyan, magenta, yellow) and K (black) having different hues. The color printer 1 is connected to the controller 2 via a communication interface.

The controller 2 is a PC or the like. The controller 2 acquires a print job from another computer connected via the network. Then, the controller 2 generates raster image data by RIP (Raster Image Processor) development processing for the acquired print job.
The controller 2 stores the device link profile transmitted from the client PC 10 in a storage device such as an HDD. The controller 2 can perform color conversion processing on the generated image data using a device link profile. The controller 2 transmits the image data subjected to the color conversion process to the color printer 1 for output.
Here, the device link profile is a profile obtained by integrating the device profile of the color monitor device and the device profile of the color printer 1. Specifically, the device link profile associates the RGB values of the color monitor device with the CMYK values of the color printer 1 without using a device-independent color space. Therefore, the controller 2 can directly convert RGB image data output from the color monitor device into CMYK colors using the device link profile.
In this embodiment, in order to reduce the amount of color material (toner material) used by the color printer 1, the controller 2 stores the color adjustment table transmitted from the client PC 10 in an HDD or the like as will be described later. Store in the device. Based on these, the controller 2 can perform color adjustment on the CMYK image data converted by the device link profile.

The measuring device 3 measures a color chart or spot color chart output from the color printer 1. Specifically, the measuring device 3 spectroscopically measures the color of each color patch included in the color chart and the color chart of the spot color. Then, the measuring instrument 3 transmits the measured value of the measured color to the client PC 10. Here, the measurement value obtained by the measuring instrument 3 is represented by a spectral reflectance value, a value of a color system that does not depend on a device such as XYZ and L ^* a ^* b ^* determined by the International Commission on Illumination (CIE), and the like. . Here, the spot color is not a color constituted by a combination of CMYK color materials, but other colors that cannot be represented by CMYK, or offset printing that is created by mixing each color material of CMYK. It is a special color ink used and may be included in image data for offset printing. Since the color printer 1 cannot output such a spot color as it is, it is necessary to perform measurement by the measuring device 3 and convert it into CMYK values as described later.
The measuring device 3 is connected to the client PC 10 via a communication interface.
In addition, when the measurement value by the measuring device 3 is expressed by the spectral reflectance value or the XYZ value, the client PC 10 converts the measurement value into an L ^* a ^* b ^* value or a CIECAM02 value. Also good.
In the present embodiment, a case where the value of L ^* a ^* b ^* is used as a measurement value by the measuring device 3 will be described.

  For example, as shown in FIG. 2, the client PC 10 includes a CPU (Central Processing Unit) 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, an operation unit 14, a display unit 15, The storage unit 16 and the communication unit 17 are included.

The CPU 11 executes various programs (program codes) stored in the ROM 13 in accordance with input signals input from each unit of the client PC 10. Furthermore, the CPU 11 outputs an output signal to each unit based on the program related to the execution, and controls the overall operation of the client PC 10. That is, the CPU 11 constitutes a control unit.
For example, the CPU 11 creates a device profile for the color printer 1. Further, the CPU 11 creates a device link profile using the device profile of the color printer 1 and the device profile of the color monitor device. That is, the CPU 11 adjusts the color of the image data output from the color monitor device, and creates a color conversion table for reproducing the color of the image data by the color printer 1. Further, the CPU 11 creates a spot color table for reproducing the color indicated by the spot color by the color printer 1 based on the measured value of the spot color measured by the measuring device 3. Further, as will be described later, the CPU 11 creates a color adjustment table used in a saving mode for reducing the amount of color material (toner material) used by the color printer 1.

  The RAM 12 forms a work area for temporarily storing various programs executed by the CPU 11 and data related to the programs.

  The ROM 13 is composed of a nonvolatile semiconductor memory or the like. The ROM 13 is a medium that stores various programs executed by the CPU 11 in the form of program codes readable by the CPU 11. The ROM 13 stores parameters, files, and the like that are necessary for the CPU 11 to execute the program.

  The operation unit 14 includes a keyboard having cursor keys, character input keys, and various function keys, and a pointing device such as a mouse. The operation part 14 will output the operation signal according to operation content to CPU11, if the operation input by a user is received.

  The display unit 15 is configured by an LCD (Liquid Crystal Display) or the like. The display unit 15 displays various operation screens and various processing results in accordance with instructions from the CPU 11.

The storage unit 16 is a storage device such as an HDD (Hard Disk Drive). The storage unit 16 stores a device profile, a device link profile, and a spot color table of the color printer 1 created by the CPU 11.
The storage unit 16 stores a color adjustment table created by the CPU 11.
The storage unit 16 stores a device profile in sRGB format in advance as a device profile of the color monitor device. The device profile in the sRGB format is a device profile that conforms to an international standard defined by the International Electrotechnical Commission (IEC).

The communication unit 17 is a communication interface that connects the client PC 10 to the controller 2 and the measuring device 3. The communication unit 17 transmits / receives data between the controller 2 and the measuring device 3.
For example, the communication unit 17 receives the measurement value of the color chart transmitted from the measuring device 3. In addition, the communication unit 17 transmits the device profile, device link profile, color adjustment table, and the like stored in the storage unit 16 to the controller 2.

  Next, a procedure for creating a device profile of the color printer 1 by the client PC 10 will be described. Here, the device profile of the color printer 1 is composed of two conversion tables, a first LUT (Look Up Table) 100 and a second LUT 200. The first LUT 100 is a conversion table used when the device profile is selected on the input side when performing color adjustment, and the second LUT 200 is the case where the device profile is selected on the output side. Is a conversion table used for

The first LUT 100 is a conversion table for converting a combination of CMYK values into L ^* a ^* b ^* values of the color system. For example, as shown in FIG. 3, the first LUT 100 corresponds to an LUT input point (lattice point) that is a combination of CMYK values of C × M × Y × K: 9 × 9 × 9 × 9 = 6561 points. The four-dimensional input / 3-dimensional output LUT in which the value of L ^* a ^* b ^* is entered. Here, the values of the nine CMY values are C, M, and Y: 0%, 10%, 20%, 30%, 40%, 55%, 70%, 85%, and 100%. The nine K values are K: 0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100%.
A procedure for creating the first LUT 100 will be described below.

  First, the CPU 11 of the client PC 10 causes the color printer 110 to output the color chart 110 shown in FIG. 4 via the controller 2 without performing color adjustment. Here, the image data for outputting the color chart 110 is stored in advance in the storage unit 16 or the like. As the color chart 110, for example, a general color chart conforming to the ISO12642 standard is used. Any color chart can be used. The color chart 110 divides the maximum value 100% of each value of CMYK into a plurality of colors, and includes color patches of colors according to combinations of the divided CMYK values. Here, even when the color chart 110 is output without performing color adjustment, the calibration correction processing for correcting the output fluctuation of the color printer 1 in the color printer 1 or the like, the improvement of fixing property, or the high In order to improve the output stability of the density part, a process of limiting the total value of CMYK (maximum 400%) to, for example, maximum 300% may be performed. Further, in the processing by the controller 2 instead of inside the color printer 1, processing for limiting the total value of CMYK after color adjustment and before transfer to the color printer 1 may be performed. Such processing may be performed in normal output processing in addition to the output of the color chart 110.

Specifically, as shown in FIG. 4, the color chart 110 includes (1) K: 0%, (2) K: 20%, (3) K: 40%, (4) K: 60%, ( 5) K: 80%, (6) K: 100% are provided. In the color chart 110, for each of (1) to (6), a plurality of color patches in which CMY values are combined are arranged. For example, at K: 0% in (1), as shown in FIG. 5, C × M × Y: 6 × 6 × 6 color patches are arranged. Here, the respective values of the six CMY are C, M, and Y: 0%, 10%, 20%, 40%, 70%, and 100%. Similarly, the color chart 110 includes color patches (C, M, Y: 0%, 10%, 20%, 40) of C × M × Y: 6 × 6 × 6 on K: 20% of (2). %, 70%, 100%), K: 40% of (3), C × M × Y: 5 × 5 × 5 color patches (C, M, Y: 0%, 20%, 40%) , 70%, 100%) to K: 60% of (4), C × M × Y: 5 × 5 × 5 point color patches (C, M, Y: 0%, 20%, 40%, 70%, 100%) to K: 80% of (5), C × M × Y: 4 × 4 × 4 color patches (C, M, Y: 0%, 40%, 70%, 100) %), K: 100% of (6), and C × M × Y: 2 × 2 × 2 color patches (C, M, Y: 0%, 100%), respectively. The color chart 110 includes (7) 13 gradation steps for each CMYK single color (3%, 7%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%). 70%, 80%, 90%).
That is, the color chart 110 includes 806 color patches of C × M × Y × K: 754 points + monochromatic 52 points in total of (1) to (7).

Next, the user measures each color patch of the output color chart 110 with the measuring device 3 in order. Then, the CPU 11 uses the measuring device 3 to obtain L ^* a ^* b ^* values (measured values) corresponding to the CMYK value combinations of 754 points and the CMYK single color 52 point values, respectively. You can get it.

Next, the CPU 11 calculates the values of L ^* a ^* b ^* corresponding to the combinations of CMYK values of C × M × Y × K: 9 × 9 × 9 × 9 = 6531 points, except for the above 806 points. To do.
Specifically, the CPU 11 uses C × M × Y: 6 × 6 × 6 points in (1) as sample points, and uses each value of CMY monochromatic gradation steps in (7) to obtain C × M × Y: Interpolation processing is performed for points with no measurement value (C, M, Y: 30%, 55%, 85%) among 9 × 9 × 9 points, and L ^* a ^* b ^{* of the} point with no measurement value Is calculated. Next, the CPU 11 (C) of (2) C × M × Y: 6 × 6 × 6 points, (3) C × M × Y: 5 × 5 × 5 points, (4) C × M × Y: Similar interpolation processing is performed for each of 5 × 5 × 5 points, (5) C × M × Y: 4 × 4 × 4 points, and (6) C × M × Y: 2 × 2 × 2 points. And calculate the value of L ^* a ^* b ^{* at} the point where there is no measured value. That is, the CPU 11 can interpolate C × M × Y × K: 9 × 9 × 9 × 6 points by performing interpolation processing using C × M × Y × K: 754 points as sample points.
Further, the CPU 11 performs the following interpolation processing for three points (K: 10%, 30%, 50%) having no measurement value among the K: 9 points. That is, for K: 10% C × M × Y: 9 × 9 × 9 points, the already obtained K: 0% C × M × Y: 9 × 9 × 9 points L ^* a ^* Interpolation processing is performed using the b ^* value, K: 20% C * M * Y: 9 * 9 * 9 L ^* a ^* b ^* values, and K monochromatic gradation step values. Go to calculate the value of L ^* a ^* b ^* for each point. In addition, for K: 30% C × M × Y: 9 × 9 × 9 points, the already obtained K: 20% C × M × Y: 9 × 9 × 9 points L ^* a ^* Interpolation is performed using the b ^* value, K: 40% C × M × Y: 9 × 9 × 9 point L ^* a ^* b ^* values, and K monochromatic gradation step values. Go to calculate the value of L ^* a ^* b ^* for each point. In addition, for K: 50% C × M × Y: 9 × 9 × 9 points, the already obtained K: 40% C × M × Y: 9 × 9 × 9 points L ^* a ^* Interpolation is performed using the b ^* value, K: 60% C × M × Y: 9 × 9 × 9 point L ^* a ^* b ^* values, and K monochromatic gradation step values. Go to calculate the value of L ^* a ^* b ^* for each point.
As described above, the CPU 11 can acquire the value of L ^* a ^* b ^* for the LUT input points of C × M × Y × K: 9 × 9 × 9 × 9 = 6561 points in the first LUT 100.

Incidentally, the interpolation processing is described in detail in, for example, Japanese Patent Application Laid-Open No. 2003-78773. As an example, the interpolation processing using (4) C × M × Y: 5 × 5 × 5 points as sample points will be briefly described.
CPU11 is the ^L * ^a * ^{b *} values of points for performing an interpolation process (not a point of measurement), and the sample point ^L * ^a * ^{b *} values, and the value of gradation steps in a single color of CMY, Calculate with Here, L ^* a ^* b ^{* at the} point where interpolation processing is performed is Lm ^* am ^* bm ^* , and L ^* a ^* b ^{* at} each sample point is Li ^* ai ^* bi ^* (i = 1 to 4).
In FIG. 6, the mark ● represents a sample point, and the marks Δ and x represent points at which interpolation processing is performed. The CPU 11 uses Lm ^* am by using different interpolation formulas when there are two sample points each before and after as indicated by Δ and when there are one and three sample points before and after as indicated by ^{×. *} Calculate the value of bm ^* .
Specifically, the interpolation equation for the former (Δ mark) is obtained by the following equations (1) to (3).
Lm ^* = − (1/16) L1 ^* + (9/16) L2 ^* + (9/16) L3 ^* − (1/16) L4 ^* (1)
am ^* = − (1/16) a1 ^* + (9/16) a2 ^* + (9/16) a3 ^* − (1/16) a4 ^* (2)
bm ^* = − (1/16) b1 ^* + (9/16) b2 ^* + (9/16) b3 ^* − (1/16) b4 ^* (3)
On the other hand, the interpolation formula for the latter (x mark) is obtained by the following formulas (4) to (6).
Lm ^* = (5/16) L1 ^* + (15/16) L2 ^* − (5/16) L3 ^* + (1/16) L4 ^* (4)
am ^* = (5/16) a1 ^* + (15/16) a2 ^* -(5/16) a3 ^* + (1/16) a4 ^* (5)
bm ^* = (5/16) b1 ^* + (15/16) b2 ^* − (5/16) b3 ^* + (1/16) b4 ^* (6)
Next, the CPU 11 uses the above interpolation formula to perform interpolation processing included in C × M × Y: 9 × 9 × 9 points in the order of numbers I to III shown in FIG. Repeat the interpolation process. As a result, when the interpolation processing is completed, the CPU 11 interpolates to C × M × Y: 9 × 9 × 9 points with the sample points of C × M × Y: 5 × 5 × 5 points in (4). Can do.

As described above, the CPU 11 can create the first LUT 100. However, as described above, the CPU 11 sets the CMY values for the first LUT 100 to C, M, Y: 0%, 10%, 20%, 30%, 40%, 55%, 70%, The values of 85%, 100%, and K are set to K: 0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100%. That is, each of the nine CMYK values is not a value obtained by dividing the maximum value 100% into eight equal parts.
Therefore, the CPU 11 converts each value of CMYK into a value obtained by dividing 100% into eight equal parts by using the one-dimensional LUTs 120 and 130 shown in FIG. Then, the CPU 11 performs processing for inputting the converted values of CMYK to the first LUT 100. Specifically, the CPU 11 uses the one-dimensional LUT 120, C, M, Y: 10% to 12.5%, 20% to 25%, 30% to 37.5%, 40% to 50% %, 55% to 62.5%, 70% to 75%, and 85% to 87.5%. Further, the CPU 11 uses the one-dimensional LUT 130 to change K: 10% to 12.5%, 20% to 25%, 30% to 37.5%, 40% to 50%, 50% to 62%. Convert to 5%, 60% to 75%, and 80% to 87.5%.

The second LUT 200 converts the value of L ^* a ^* b ^* into a combination of CMYK values. Second LUT200, as shown in FIG. ^{9, L * × a * ×} b *: 33 × 33 × 33 = relative LUT input point of ^L * ^a * ^{b *} values of 35937 points, CMYK values Is a 3D input / 4D output LUT. In the present embodiment, only one second LUT 200 is described. For example, it is described in PDL (Page Description Language) included in the job data of a print job transmitted from the client PC 10 or the like. A plurality of second LUTs 200 are prepared corresponding to a plurality of types of object information such as text, graphics, and images, and a plurality of types of color matching methods such as “colorimetric”, “perceptual”, and “saturation”. May be.
A procedure for creating the second LUT 200 will be described below. For simplicity, the basic color will be described as two colors C and M. Note that C, M, Y, and K all take values of 0 to 100%.

First, the CPU 11 determines the C * M * Y * K: 9 * 9 * 9 * 9 in the first LUT 100 created as described above from the four-dimensional data that are L ^* a ^* b ^* values. × M × Y: Conversion to three-dimensional data that is L ^* a ^* b ^* values for 9 × 9 × 9 is performed. For this purpose, for example, the method described in the specification of Japanese Patent No. 2898030 can be used.

For example, first, each value of CMY is equally divided into eight to create LUT-A, which is an LUT input point of C × M × Y: 9 × 9 × 9. The number of LUT input points in LUT-A can be arbitrarily set. Next, the CMYK value to which the K value for enhancing the gray component is added is input for each LUT input point of the LUT-A. The K value for emphasizing the gray component is calculated using the K curve 0 shown in FIG. 17 based on the minimum value of CMY indicated by the LUT input point. That is, the K curve 0 (K ₀ ) can be expressed by the following equation (7). Here, if the minimum value of CMY is min [C, M, Y],
K ₀ = 2.0 (min [C, M, Y] −50 (%)) (7)
However, if K ₀ <0, K ₀ = 0 (%).
In FIG. 17, the K curve 0 is illustrated as a straight line. However, the K curve 0 may be a curved line around the start point or a curved line as a whole.

The K value obtained as described above is input to the LUT input point together with each value of CMY. For example, the CMYK value input to the LUT input point (C: 62.5%, M: 75%, Y: 87.5%) will be described. First, since the minimum value of CMY is 62.5%, The K value is calculated as (K: 25%). As a result, the CMYK value input to the LUT input point is obtained by adding the K value to each of the CMY values (C: 62.5%, M: 75%, Y: 87.5%, K: 25%). Similarly, CMYK values are obtained and input for other LUT input points.
The K curve used for obtaining the K value is not limited to the one described above. In addition, as described later, the CMYK value input to the LUT input point may be set so as to reduce the total amount of CMYK color materials. Here, in the present embodiment, information on the used K curve and information indicating the color material limit amount are stored together with the second LUT 200, for example. The reason for holding these pieces of information is to make the ratio of the K value to the CMYK value larger than that obtained as described above when obtaining the CMYK value when creating a color adjustment table to be described later. . In other words, when the CMYK value is obtained, the ratio of the CMY value to the CMYK value is made smaller than that obtained above. That is, at the time of creating the color adjustment table, the amount by which the total amount of the K curve and / or color material to be used is reduced is greater than the ratio at the time of creating the second LUT 200 to the CMYK value. It is. In this embodiment, the K curve used when creating the second LUT 200 is K curve 0, and the color material limit is 400%.

Next, in the same manner, each value of CMY is equally divided into eight to create LUT-B, which is a C × M × Y: 9 × 9 × 9 LUT input point. Each LUT input point of LUT-B corresponds to each LUT input point of LUT-A. Then, L ^* a ^* b ^* values corresponding to the CMYK values input to the respective LUT input points of the LUT-A are obtained by interpolation using the first LUT 100, and the corresponding LUT inputs of the LUT-B are obtained. Enter a point.

As described above, C × M × Y × K: 9 × 9 × 9 is obtained by obtaining CMYK values and L ^* a ^* b ^* values for C × M × Y: 9 × 9 × 9 = 729 points. C.times.M.times.Y: 9.times.9.times.9 three-dimensional data can be created from the .times.9 four-dimensional data.

Next, the CPU 11 uses the LUT-A and LUT-B created as described above, and CMYK values for the LUT input points of L ^* × a ^* × b ^* : 33 × 33 × 33 points. The combination of is derived.
First, in a combination of L ^* × a ^* × b ^* : 33 × 33 × 33 points, a point where a measured value of L ^* a ^* b ^* exists (that is, a point inside the color gamut of the color printer 1). A procedure for deriving a combination of CMYK values will be described. Here, the color gamut is a color range that can be expressed or reproduced by a device that performs image data output processing such as the color printer 1.
The convergence calculation process used for the derivation is described in detail in, for example, Japanese Patent Laid-Open No. 2003-78773. Here, the derivation procedure will be briefly described.

FIG. 10 shows the lightness L ^* on the vertical axis and the lightness L ^* on the horizontal axis for a combination of C × M: 9 × 9 points (Y: 0%) consisting of two-dimensional CM values among the three-dimensional CMY values. This is a coordinate system in which a ^* is plotted. In FIG. 10, H1 ′ and H2 ′ represent saturation vertices, W ′ represents a white vertex, and B ′ represents a blue vertex. In practice, the CPU 11 performs a derivation process for a three-dimensional CMY value, but for the sake of simplicity, a derivation process for a two-dimensional CM value will be described.

In FIG. 10, the target value T ′ is the value of L ^* a ^* b ^* of a target point for which a combination of CMY values is to be obtained among L ^* × a ^* × b ^* : 33 × 33 × 33 points. It is. It is assumed that the target value T ′ is present in a region V0 ′ surrounded by the lattice points a ′ to d ′ in FIG. In this case, the CPU 11 estimates that the target value T, which is a combination of CM values in the CM coordinate system, is within the region V0 surrounded by the lattice points a to d shown in FIG. In FIG. 11, H1 and H2 correspond to the saturation vertices H1 ′ and H2 ′, W corresponds to the white vertex W ′, and B corresponds to the blue vertex B ′.
Next, the CPU 11 divides the region V0 surrounded by the lattice points a to d shown in FIG. 11 into four equal regions V1 to V4 at the dividing points e to i shown in FIG. Here, the CPU 11 calculates the values of the dividing points e to i by the weighted average using the surrounding grid points that have already been obtained. Then, the CPU 11 plots the values of L ^* a ^* b ^* corresponding to the dividing points e to i in the coordinate system shown in FIG. Dividing points e ′ to i ′ shown in FIG. 13 are plot points corresponding to dividing points e to i shown in FIG.
Further, the CPU 11 determines which region of the four regions V1 ′ to V4 ′ formed by the dividing points e ′ to i ′ has the target value T ′. For example, when the target value T ′ is in the region V2 ′ as shown in FIG. 13, the CPU 11 estimates that the target value T is in the region V2 corresponding to the region V2 ′ shown in FIG.

  Next, the CPU 11 divides the estimated region V2 into regions V5 to V8, and estimates which region of the divided regions V5 to V8 has the target value T. In the same manner, the CPU 11 repeats the division / estimation of the regions, and converges the regions V0, V1 to V4, V5 to V8, V9 to V12,. Then, the CPU 11 can obtain the target value T (combination of CM values) from the average value of the four grid points or division points that form the converged area. However, the actual CPU 11 calculates the target value T (combination of CMY values) for each target point one by one for the three-dimensional CMY values. That is, the CMY value is calculated by performing a reverse calculation from the LUT-B generated as described above. Since LUT-B corresponds to LUT-A generated as described above, it can be obtained by interpolating a combination of CMYK values from the calculated CMY values. Note that the CPU 11 performs the convergence calculation process because the conversion from the coordinate system of FIG. 11 to the coordinate system of FIG. 10 is known, but the reverse conversion is very complicated and is still a good conversion formula. This is because is not known.

  In the present embodiment, the method based on the convergence calculation as described above is described. However, for example, an interpolation method described in the specification of Japanese Patent No. 2895086 may be used.

^{Then, L * × a * × b} *: Among 33 × 33 × 33 ^points, for the case where L ^* a * ^{b *} value is outside the gamut, a procedure for deriving a combination of CMYK values explain. In this case, the CPU 11 executes color gamut mapping (color gamut mapping) processing. That is, the CPU 11 maps the value of L ^* a ^* b ^{* to} a value inside the color gamut and derives a combination of CMYK values by the above-described convergence calculation process. The color gamut mapping will be described below.

FIG. 14 is a cross section obtained by cutting the L ^* a ^* b ^* color system space in a direction including the L ^* axis with a certain hue. Here, in FIG. 14, B ′ represents a black vertex (black vertex). In FIG. 14, shaded portions having four vertices including the saturation vertex H1 ′, the white vertex W ′, the saturation vertex H2 ′, and the black vertex B ′ are the color gamut of the color printer 1.

First, the CPU 11 calculates the hue angle h and the saturation C ^* using the values of a ^* and b ^* . The hue angle h can be calculated by the following formula (8), and the saturation C ^* can be calculated by the following formula (9).
h = arctan (b ^* / a ^* ) / π × 180 (8)
C ^* = ((a ^* ^ 2) + (b ^* ^ 2)) ^ 0.5 (9)

Next, the CPU 11 obtains the lightness L ^* and saturation C ^* of the saturation vertex H1 ′, the white vertex W ′, and the black vertex B ′ for the color gamut of the color printer 1 at the hue angle h. For example, the lightness L ^* and saturation C ^* of the saturation vertex H1 ′ are calculated as follows. CPU 11 has M: 100% and C, Y: 0% point, M, Y: 100% and C: 0% point, Y: 100% and M, C: 0% point, C, A point of Y: 100% and M: 0%, a point of C: 100% and M, Y: 0%, and a point of C, M: 100% and Y: 0% are connected. And CPU11 acquires the value of L ^* a ^* b ^* corresponding to the value of CMY of each connected point. Further, the CPU 11 calculates the hue angle h and the saturation C ^* from the acquired values of L ^* a ^* b ^* at each point. Further, the lightness L ^* and the saturation C ^* of the saturation vertex H1 ′ are calculated by performing an interpolation calculation using the hue angle h and the saturation C ^* of each point calculated by the CPU 11.

Next, the CPU 11 makes the hue angle h constant and determines which of the areas P1 to P5 shown in FIG. 14 belongs to a point (input point) outside the color gamut. Then, the CPU 11 maps the input point to the color gamut based on the mapping procedure determined for each of the regions P1 to P5, and determines the target point on the color gamut corresponding to the target value T ′.
Here, in the present embodiment, the high saturation color target point r1 is determined at a position where the saturation C ^* is smaller than the saturation vertex H1 ′. That is, as shown in FIG. 14, the CPU 11 arranges the target point r1 on the saturation vertex H1 ′ side on the line segment connecting the intermediate point r2 and the saturation vertex H1 ′. Further, the CPU 11 arranges a target point r3 of a color near the white vertex W ′. The CPU 11 determines the target point r3 so as to be positioned on a line segment connecting the white vertex W ′ and the intermediate point r2. The intermediate point r2 is a point that takes an intermediate value between the lightness L ^* of the white vertex W ′ and the lightness L ^* of the black vertex B ′.

First, the CPU 11 determines the boundaries of the areas P1 to P5 shown in FIG.
Specifically, the CPU 11 determines the inclinations of the region P2 and the region P4 based on a predetermined method. Here, the area P2 is an area that is located above the color gamut and that maps to the color gamut with the inclination determined by the CPU 11. The region P4 is located below the color gamut and is a region that maps to the color gamut with an inclination determined by the CPU 11.
And CPU11 creates boundary lines q1-q4 based on the inclination of field P2 and field P4. CPU11 defines the boundary of each area | region of the area | regions P1-P5 with the created boundary lines q1-q4. The boundary line q1 is a half line extending upward from the color gamut with the inclination of the region P2 from the target point r3. The boundary line q2 is a half line extending upward from the color gamut with the inclination of the region P2 from the target point r1. The boundary line q3 is a half straight line that extends downward from the target point r1 with a slope of the region P4 toward the lower side of the color gamut. The boundary line q4 is a half line extending downward from the color gamut with the inclination of the region P4 from the black vertex B ′.
Here, in FIG. 14, the lightness L ^* of the saturation vertex H1 ′ indicates a substantially intermediate value of the maximum value 100 of the lightness L ^* . However, the lightness L ^* of the saturation vertex H1 ′ may not show the substantially intermediate value depending on the hue to be cut. For example, when cut with yellow hue, the lightness L ^* of chroma vertex H1 ', shows high lightness L ^* than 14. Further, when cut with a blue hue, the lightness L ^* of the saturation vertex H1 ′ indicates a lightness L ^* lower than that in FIG. In such a case, it is desirable for the CPU 11 to change the slopes of the areas P2 and P4 in accordance with the slopes of the straight lines from the saturation vertex H1 ′ to the white vertex W ′ and the black vertex B ′.

Next, the CPU 11 determines the slope of the line segment connecting the input point and the target point r3, the slope of the line segment connecting the input point and the target point r1, and the line segment connecting the input point and the intermediate point r2. Is calculated. Then, CPU 11 has a respective gradients calculated, and the result of comparison between the lightness L ^* lightness L ^* and chroma vertex H1 'of the input point, based on, any region of the input point region P1~P5 Determine if it belongs to.
Next, the CPU 11 determines a target point in the color gamut for mapping the input point according to the area to which the input point belongs. For example, when the CPU 11 determines that the input point belongs to the region P1, the CPU 11 determines the target point as the target point r3. On the other hand, when the CPU 11 determines that the input point belongs to the region P3, the CPU 11 determines the target point as the target point r1. Further, when the CPU 11 determines that the input point belongs to the region P5, the CPU 11 determines the target point as the black vertex B ′. When the CPU 11 determines that the input point belongs to the region P2, the CPU 11 passes through the input point and the line segment connecting the target point r1 and the white vertex W ′ or the line segment connecting the target point r3 and the intermediate point r2 through the input point P2. The intersection point with the straight line drawn with the inclination of is determined as the target point. When the CPU 11 determines that the input point belongs to the region P4, the CPU 11 passes the line segment connecting the target point r1 and the white vertex W ′ or the line segment connecting the black vertex B ′ and the intermediate point r2 and the input point. The intersection point with the straight line extended with the inclination of P4 is determined as the target point.
As a result, the CPU 11 can map the input point whose L ^* a ^* b ^* value is outside the color gamut to the target point within the color gamut. And CPU11 acquires the combination of the value of CMYK by performing a convergence calculation process about target value T 'of the said target point.

As described above, the CPU 11 derives a combination of CMYK values for each LUT input point of L ^* a ^* b ^* : 33 × 33 × 33 = 35937 points, and generates the second LUT 200.

  Next, a procedure for creating a device link profile executed in the color adjustment system 1000 will be described with reference to FIG.

First, the color chart 110 shown in FIG. 4 is output by the color printer 1, and the color chart 110 output by the measuring device 3 is measured as described above (step S1).
Next, based on the measurement result of the color chart 110, the CPU 11 of the client PC 10 creates the first LUT 100 as described above and stores it in the storage unit 16 (step S2).
Then, the CPU 11 creates the second LUT 200 based on the created first LUT 100 as described above, and stores it in the storage unit 16 (step S3).
Then, the CPU 11 reads out the second LUT 200 created as described above and stored in the storage unit 16 and the device profile of the color monitor device stored in advance in the storage unit 16 (step S4). The device profile of the color monitor apparatus read out here is a profile for acquiring L ^* a ^* b ^* values corresponding to RGB values as inputs, and may be referred to as a source profile. Further, the profile including the second LUT 200 read out here may be referred to as a destination profile.
Then, the CPU 11 creates a device link profile by using the read second LUT 200 as the destination profile and the device profile of the color monitor device as the source profile (step S5). More specifically, first, an L ^* a ^* b ^* value corresponding to RGB values at the grid points of the source profile is used as an input value of the second LUT 200, and an output value of CMYK is obtained by interpolation calculation. Then, a device link profile is created by configuring an “RGB-CMYK LUT” having the RGB values at the grid points of the source profile as the LUT input points and the CMYK values obtained as described above as output values. This device link profile is a normal mode device link profile in which a color conversion result in a normal time is obtained, in which color materials are not reduced in a saving mode, which will be described later.

Here, when sufficient accuracy cannot be obtained even when color conversion from RGB values to CMYK values is performed, for example, as described in detail in the specification of JP2011-10231A, correction of color differences is performed. The device link profile may be created by performing feedback processing for performing the above. Specifically, first, a color chart converted from RGB values to CMYK values is output by the color printer 1, and the output color chart is measured by the measuring device 3. Next, the L ^* a ^* b ^* value corresponding to the CMYK value, which is the color converted value, is obtained by interpolation calculation using the first LUT (CMYK-L ^* a ^* b ^* LUT) of the color printer 1. The L ^* a ^* b ^* value is held as an output target value. Next, the color difference between the output target value and the measured value is obtained. The L ^* a ^* b ^* value of the point obtained by moving the output target value in the direction opposite to the measured value by an amount corresponding to the color difference thus determined is corrected to L ^* a ^* b ^*. By using the value, the color difference can be corrected.

  For example, as detailed in Japanese Patent No. 3785688, the device link profile may be created after fine adjustment of the value of CMYK output from the second LUT 200.

  In the present embodiment, the color for which the color material is reduced as described below with respect to the CMYK values obtained as a result of color conversion using the normal mode device link profile created as described above. Perform the adjustment process.

  Next, processing for color adjustment performed in the color adjustment system 1000 will be described with reference to FIGS.

  First, when performing color adjustment processing, a color adjustment table is created. Here, the color adjustment table creation processing will be described with reference to FIG. The color adjustment table creation process is a process executed by the CPU 11 of the client PC 10. In the present embodiment, three color adjustment tables are created as a color adjustment table: a saving mode weak table, a saving mode medium table, and a saving mode strong table. Any of the saving mode weak table, the saving mode middle table, and the saving mode strong table can be created by the color adjustment table creation processing described below. The number of color adjustment tables to be created is arbitrary and may be two, four or more, or only one table may be created. Further, each saving intensity shown here is based on the saving amount obtained by calculating the numerical value of the entire image before and after conversion from the output CMYK value to the adjusted CMYK value. The amount of color material required for the color image does not necessarily match, and the actual saving amount varies depending on the output image.

First, the CPU 11 creates an LUT-C (step S101). Specifically, the CPU 11 creates LUT-C in the same manner as LUT-A described above. Here, the CPU 11 selects a K curve to be used based on the information on the K curve and the information indicating the color material limit amount stored in the storage unit 16 as described above. In the present embodiment, the K curve used when the second LUT 200 is created is K curve 0 and the color material limit amount is 400%. Therefore, when creating the saving mode weak table, As shown in FIG. 17, the K value is calculated using a K curve 1 that is increased by one step from the K curve 0. Further, when the saving mode medium table is created, the K value is calculated using the K curve 2 which is increased by two steps from the K curve 0. Further, when the saving mode strong use table is created, the K value is calculated using the K curve 3 that is increased by three stages from the K curve 0. Here, K curve 1 (K ₁ ), K curve 2 (K ₂ ), and K curve 3 (K ₃ ) can be expressed by the following equations (10) to (12). In the following formula, min [C, M, Y] is the minimum value of CMY.
K ₁ = 1.6 (min [C, M, Y] -37.5 (%)) (10)
However, if K ₁ <0, K ₁ = 0 (%).
K ₂ = 1.3333 (min [C, M, Y] −25 (%)) (11)
However, if K ₂ <0, K ₂ = 0 (%).
K ₃ = 1.1429 (min [C, M, Y] -12.5 (%)) (12)
However, if K ₃ <0, K ₃ = 0 (%).
In this way, by using a K curve such that the calculated K value is larger than when the second LUT 200 is created, when the third LUT 300 to be described later is created, the CMYK of the CMY value is obtained. The ratio with respect to the value can be made smaller than when the second LUT 200 is created.
In FIG. 17, the K curve 1 to K curve 3 are all illustrated as straight lines. However, the K curve 1 to K curve 3 may be curved in the vicinity of the start point or curved in its entirety.

  Next, the CPU 11 determines whether or not the color adjustment table to be created is a saving mode weak table (step S102). When the CPU 11 does not determine that the color adjustment table to be created is the saving mode weak table, that is, when the CPU 11 determines that the table to be created is the saving mode medium table and the saving mode strong table (step S102: N). ), The total amount restriction setting process is executed (step S103). Details of the total amount restriction setting process will be described later. On the other hand, when the CPU 11 determines that the color adjustment table to be created is the saving mode weak table (step S102: Y), the CPU 11 executes the process of step S104 without executing the process of step S103.

In step S104, the CPU 11 creates an LUT-D (step S104). Specifically, the CPU 11 creates the LUT-D in the same manner as the LUT-B described above. Here, each LUT input point of LUT-D corresponds to each LUT input point of LUT-C. The CPU 11 obtains an L ^* a ^* b ^* value corresponding to the CMYK value input to each LUT input point of the LUT-C by interpolation using the first LUT 100, and each of them corresponds to the LUT corresponding to the LUT-D. LUT-D is created by inputting to the input point.

Next, the CPU 11 creates the third LUT 300 using the LUT-C and LUT-D created as described above (step S105). The third LUT 300 is the same as the second LUT 200, and as shown in FIG. 18, L ^* × a ^* × b ^* : 33 × 33 × 33 = 35937 points of L ^* a ^* b ^* values. This is a three-dimensional input / four-dimensional output LUT in which the value of CMYK enters the LUT input point. The CPU 11 creates a third LUT 300 in the same manner as the second LUT 200 and stores it in the storage unit 16.

  The CPU 11 reads out the first LUT 100 and the third LUT 300 created as described above and stored in the storage unit 16 (step S106).

Then, the CPU 11 creates a color adjustment table using the read first LUT 100 and third LUT 300 (step S107), and ends this process. Specifically, the CPU 11 first uses the L ^* a ^* b ^* value corresponding to the CMYK value at the lattice point of the first LUT 100 as the input value of the third LUT 300, and obtains the output value of CMYK by interpolation calculation. In the present embodiment, this output value may be referred to as an adjusted CMYK value. Then, the CPU 11 uses the CMYK value at the lattice point of the first LUT 100 as the LUT input point, and the color adjustment configured by “CMYK-CMYK LUT” using the adjusted CMYK value obtained as described above as the output value. Create a table.

  Next, the total amount restriction setting process executed in step S103 of the color adjustment table creation process described above will be described with reference to FIG.

  First, the CPU 11 determines whether there is an LUT input point to be converted among the LUT input points in the created LUT-C (step S201). Specifically, the CPU 11 searches for a LUT input point where the sum of the CMYK values is 220% to 400% and the CMY value has not yet been converted as a conversion target. It should be noted that the total of the CMYK values to be converted of the LUT input points can be arbitrarily set.

  When the CPU 11 determines that there is an LUT input point to be converted (step S201: Y), the CPU 11 reads the CMYK value described in the LUT input point (step S202).

  Then, the CPU 11 performs conversion so that the sum of the read values of CMYK is less than or equal to a predetermined maximum value (step S203). That is, the CPU 11 converts the total of CMYK values from 220% to 400% from 220% to the maximum value using a predetermined one-dimensional LUT. Here, the maximum value is determined based on the information on the K curve and the information indicating the color material limit amount held together with the second LUT 200 as described above. In this embodiment, the K curve used when the second LUT 200 is created is the K curve 0, and the color material limit amount is 400%. For example, when the saving mode medium table is created. The maximum value is set to 330%, and the maximum value is set to 270% when the saving mode strong use table is created.

  Then, the CPU 11 subtracts the K value before conversion from the total of the CMYK values converted in step S203 to calculate the total of the converted CMY values (converted CMY total value) (step S204). ).

  Then, the CPU 11 calculates a subtraction coefficient by dividing the converted CMY total value calculated in step S204 by the total of the respective CMY values before conversion (pre-conversion CMY total value) (step S205).

  Then, the CPU 11 multiplies each value of CMY at the LUT input point to be read in step S202 by the subtraction coefficient calculated in step S205, and uses each value of CMY after conversion (converted CMY value). The calculated CMYK value obtained by adding the K value before conversion to the converted CMY value is obtained (step S206).

  The above processing will be specifically described. For example, when creating a saving mode strong use table, if each value of CMYK is C = 100%, M = 100%, Y = 75%, K = 25%, The sum of each value of CMYK is 300%. When the total of CMYK values after conversion using the one-dimensional LUT is 250%, the converted CMY total value is 250−25 = 225%. Since the pre-conversion CMY total value is 275%, the subtraction coefficient is 225/275 = 0.818. Then, when this subtraction coefficient is multiplied to each value of CMY before conversion, C = 81.8%, M = 81.8%, and Y = 61.4%. Note that the K value is not multiplied by a subtraction coefficient.

  When the converted CMYK values are calculated as described above, the CPU 11 replaces the converted CMYK values with the LUT input points that were read in step S202 (step S207), and the processing of step S201 Migrate to

The CPU 11 creates the LUT-C in which the total amount of color material is limited by repeatedly executing the processing of steps S201 to S207 until there is no LUT input point to be converted.
If the CPU 11 does not determine in step S201 that there is an LUT input point to be converted (step S201: N), the CPU 11 ends this process.

As described above, the CPU 11 executes the above-described total amount restriction setting process to create the third LUT 300 using the LUT-C and LUT-D in which the total amount of color material is restricted. The total of will not exceed the maximum value. As a result, for example, when the saving mode strong use table is created, as shown in FIG. 20, the lower outer edge of the color gamut indicated by the solid line is moved up to the position indicated by the broken line, and the brightness level is increased. The color gamut narrows so that the lower part rises. In this embodiment, the total of CMYK values at each LUT input point of LUT-C is limited to 270% or 330% or less, but the limiting value can be arbitrarily set. In addition, the third LUT 300 in which the total color material amount is limited is created based on the LUT-C in which the sum of the CMYK values at each LUT input point is limited to the maximum value or less. The CMYK values respectively obtained by the third LUT 300 can be reduced while maintaining the balance. Even when an L ^* a ^* b ^* value other than the LUT input point of the third LUT 300 is input, the LUT is obtained by interpolation from the CMYK values described in the LUT input points limited to the maximum value or less. Regarding the color around the input point, the sum of the CMYK values does not exceed the limit value and does not suddenly collapse to the limit value, so that the color change from the surroundings can be made continuous. . Further, when the LUT-D is created, in order to limit the sum of the CMYK values to the above-described maximum value, the LUT-D is centered on the point where the CMY values are 100% (that is, black). The total amount of the color material is limited, and the L ^* a ^* b ^* value is input. Further, by making the color material limit amount larger than when the second LUT 200 is created, when the third LUT 300 is created, the ratio of the K value to the CMYK value is greater than when the second LUT 200 is created. Can also be increased.

  The color conversion process performed after the color adjustment table is created as described above will be described with reference to FIG. This color conversion process is a process executed by the CPU 2 of the controller 2, for example. The color conversion process performs color conversion for converting input image data such as CMYK and RGB into CMYK data for output by the color printer 1 and color adjustment for saving color materials. It is a process for performing. It should be noted that various tables such as profiles used in this color conversion process are transmitted from the client PC 10 and held in the storage device of the controller 2.

First, the controller 2 determines whether the color (color data) of the image data input from the client PC 10 or the like indicates a spot color (step S301). When the controller 2 determines that the input color data indicates a spot color (step S301: Y), the controller 2 uses the second LUT 200 to specify L ^* a ^* specified from the color data indicating the spot color ^. The b ^* value is converted into a CMYK value by interpolation calculation, and this is set as C ₁ M ₁ Y ₁ K ₁ (step S302). On the other hand, when the controller 2 determines that the input color data does not indicate a spot color, that is, determines that the input color data is RGB data (step S301: N), the controller 2 uses the normal mode device link profile, The input RGB value is converted into a CMYK value by interpolation, and this is set as C ₁ M ₁ Y ₁ K ₁ (step S303).

Then, the controller 2 determines whether or not it is a saving mode for saving color materials (step S304). The saving mode is preset by the user, for example. When it is determined that the controller 2 is in the saving mode (step S304: Y), the controller 2 determines whether each value of C ₁ M ₁ Y ₁ K ₁ is 0% (step: S305). When the controller 2 does not determine that each value of C ₁ M ₁ Y ₁ K ₁ is 0% (step: S305: N), the controller 2 determines whether the color is any one of CMYK. (Step S306). That is, the controller 2 determines whether or not the color is monochromatic depending on whether or not only one of the values of C ₁ M ₁ Y ₁ K _{1 is} a value other than 0%. If the controller 2 does not determine that the color is any one of CMYK (step S306: N), the controller 2 determines whether the color is an RGB secondary color (step S307). That is, the controller 2 determines whether or not the color is composed of two colors of CMY. Then, the controller 2, when not determined that the secondary color RGB (step S307: N), a value of _{K 1 0%,} the minimum value among the values of C ₁ M _{1 Y 1} Is less than or equal to a predetermined threshold (th0) (step S308). Note that the threshold value set here can be appropriately set according to the performance and state of the color printer. When the controller 2 does not determine that the value of K ₁ is 0% and the minimum value of each value of C ₁ M ₁ Y ₁ is equal to or less than a predetermined threshold (step S308: N), The process of step S309 is executed. On the other hand, when controller 2 does not determine that the mode is the saving mode in step S304 (step S304: N), controller 2 determines that each value of C ₁ M ₁ Y ₁ K ₁ is 0% in step S305. When (step S305: Y), when it is determined in step S306 that it is one of CMYK single colors (step S306: Y), when it is determined that it is an RGB secondary color in step S307 (step S307: Y), and, in step S308, a 0% value of _{K 1 is,} when the minimum value among the values of C ₁ M _{1 Y 1} is equal to or less than a predetermined threshold value (step S308: Y) The process of step S312 described later is executed.

  The color corresponding to any of the conditions in step S305 to step S308 is a color that is not subject to the process of replacing each value of CMY with the K value or the process of limiting the total value of CMYK, and is not always changed. A calculation error may occur when the above-described processing is performed on a color corresponding to such a condition in the same manner as other colors. For this reason, in the present embodiment, these conditions are determined, and for the corresponding color, in order to reduce the influence due to the calculation error, the following processing for saving the coloring material is not performed. ing.

  In step S309, the controller 2 reads the color adjustment table corresponding to the set saving mode (step S309). That is, when the set saving mode is a saving mode in which the saving mode is a weak saving, the controller 2 reads the saving mode weak table, and the set saving mode is a saving mode in which the saving is moderate. Reads out the saving mode medium table, and if the set saving mode is a saving mode in which a strong saving is performed, reads the saving mode strong table.

Then, the controller 2 converts each value of C ₁ M ₁ Y ₁ K ₁ into each value of C ₂ M ₂ Y ₂ K ₂ using the read color adjustment table (step S310).

Then, the controller 2 outputs C ₂ M ₂ Y ₂ K ₂ converted as described above (step S311), and ends this process. The color printer 1 outputs a color image based on each value of the output C ₂ M ₂ Y ₂ K ₂ .

On the other hand, in step S312, the controller 2 directly sets each value of C ₁ M ₁ Y ₁ K ₁ as C ₂ M ₂ Y ₂ K ₂ (step S312), and executes the process of step S311. That is, the controller 2 sets the values obtained in step S302 and step S303 as values for output by the color printer 1 as they are.

  Next, the saving mode selection process will be described with reference to FIG. This saving mode selection process is a process executed by the controller 2. This saving mode selection process is executed when there is a saving mode selection instruction from the client PC 10.

  First, when there is an instruction to select a saving mode from the client PC 10, the controller 2 sets the saving mode so that the saving mode corresponding to the instruction content is executed (step S401). That is, the controller 2 is set to any one of the normal mode, the weak saving mode for performing a moderate saving, the saving mode for performing a moderate saving, and the strong saving mode for performing a strong saving.

  Next, the saving mode device link profile generation processing will be described with reference to FIG. This saving mode device link profile generation processing is, for example, processing executed by the CPU 11 of the client PC 10. In this saving mode device link profile generation processing, based on the normal mode device link profile generated as described above and the color adjustment table, RGB values at the grid points of the source profile are used as LUT input points. A device link profile for saving mode is generated using the CMYK values corresponding to the output values as output values. This saving mode device link profile generation processing is executed for each of the saving mode weak, the saving mode in-progress, and the saving mode strong. This device link profile for saving mode is used for estimating a color material saving amount to be described later. Further, this saving mode device link profile may be used in the color conversion process described above. In the description of the saving mode device link profile generation process, only the outline of the process will be described with respect to the contents of the process overlapping with the color conversion process shown in FIG.

First, the CPU 11 reads the normal device link profile stored in the storage unit 16, reads the output CMYK value corresponding to the input RGB value at one LUT input point from the normal device link profile, and reads this value as C ₃ M _{It is set to 3} Y ₃ K ₃ (step S501).

Then, the CPU 11 determines whether or not each value of C ₃ M ₃ Y ₃ K ₃ is 0% (step: S502). Then, when the CPU 11 does not determine that each value of C ₃ M ₃ Y ₃ K ₃ is 0% (step: S502: N), the CPU 11 determines whether the color is any one of CMYK. (Step S503). If the CPU 11 does not determine that the color is any one of CMYK (step S503: N), the CPU 11 determines whether the color is an RGB secondary color (step S504). Then, CPU 11, when not determined that the secondary color RGB (step S504: N), a value of 0% of _{K 3,} the minimum value among the respective values of C ₃ M _{3 Y 3} is It is determined whether it is below a predetermined threshold (step S505).

When the CPU 11 does not determine that the value of K ₃ is 0% and the minimum value among the values of C ₃ M ₃ Y ₃ is equal to or less than a predetermined threshold (step S505: N), the color adjustment table Is read (step S506).
The CPU 11 converts each value of C ₃ M ₃ Y ₃ K ₃ into C ₄ M ₄ Y ₄ K ₄ using the read color adjustment table (step S507).

  The CPU 11 determines whether conversion data creation has been completed for all the LUT input points of the normal device link profile (step S508). That is, the CPU 11 determines whether or not conversion data for each value of CMYK after color conversion has been created for all the LUT input points of the normal device link profile.

If the CPU 11 does not determine that the creation of the conversion data has been completed for all the LUT input points (step S508: N), the CPU 11 proceeds to step S501, and conversion data to CMYK values after color conversion has been created. The above-described processing is performed for other output CMYK values that are not present. On the other hand, when the CPU 11 determines that the creation of the conversion data has been completed for all the LUT input points (step S508: Y), each input RGB value of the normal device link profile and C ₄ M ₄ Y ₄ K ₄ Are created, a device link profile for saving mode is created with the RGB values at the lattice points of the source profile as LUT input points and the corresponding C ₄ M ₄ Y ₄ K ₄ as output values, 16 (step S509), the process is terminated. In this process, the device link profile for weak saving mode, the device link profile for saving mode, and the device link profile for strong saving mode are created.

Further, when the CPU 11 determines in step S502 that each value of C ₃ M ₃ Y ₃ K ₃ is 0% (step S502: Y), in step S503, it is any one of CMYK colors. in: (Y step S503), step S504, when it is determined that the secondary color RGB when it is judged (step S504: Y), and, in step S505, the value of _{K 3} is 0% When it is determined that the minimum value among the values of C ₃ M ₃ Y ₃ is equal to or smaller than the predetermined threshold (step S505: Y), the values of C ₃ M ₃ Y ₃ K ₃ are used as they are as they are in C ₄ M _4. Y ₄ K ₄ is set (step S510), and the process of step S508 is executed.

  Next, referring to FIG. 24, a color material saving amount estimation process using the saving mode weak device link profile, the saving mode medium device link profile, and the saving mode strong device link profile created as described above will be described. While explaining. This color material saving amount estimation process is a process executed when the CPU 11 of the client PC 10 performs a print job, for example.

  First, when executing a print job, the CPU 11 displays a saving amount pre-estimation setting screen as shown in FIG. 25 on the display unit 15, and then performs the following processing according to the operation by the operation unit 14. That is, the CPU 11 determines whether or not to estimate the saving amount for all pages of the print job (step S601). Specifically, after a check input is made to the check box CB1 on the saving amount prior estimation setting screen, the saving amount is estimated for all pages of the print job depending on whether or not the saving amount estimation button B1 is operated. Determine whether to do it.

  When the CPU 11 determines to estimate the saving amount for all pages of the print job (step S601: Y), the CPU 11 performs RIP (Raster Image Processor) development at a resolution of 150 dpi on all pages of the print job. BMP (Bit Map) image data is generated (step S602). In this embodiment, while printing is performed at a resolution of 600 dpi or 1200 dpi, the processing time for performing color conversion and the estimation of the saving amount is shortened by estimating the saving amount at a low resolution of 150 dpi. In addition, the memory capacity used can be reduced. Note that the resolution for estimating the saving amount is not limited to that described above, and can be set as appropriate. Further, the resolution when estimating the saving amount may be the same as the resolution when performing printing.

  On the other hand, when the CPU 11 does not determine to estimate the saving amount for all pages of the print job, that is, the check box CB1 is unchecked, and the page is designated by operating the page transition buttons B2 and B3. When the saving amount estimation button B1 is operated (step S601: N), RIP development is performed on the designated page among the pages constituting the print job at a resolution of 150 dpi, and BMP image data is obtained. Generate.

  When the BMP image data is generated as described above, the CPU 11 converts the image data into a CMYK value (normal CMYK value) using the normal mode device link profile generated as described above. Is performed (step S604). Subsequently, the CPU 11 similarly performs color conversion on the image data into CMYK values using the saving mode weak device link profile created as described above (step S605). Subsequently, the CPU 11 similarly performs color conversion on this image data into CMYK values using the device link profile for saving mode created as described above (step S606). Subsequently, the CPU 11 similarly performs color conversion on the image data into CMYK values using the saving mode strong device link profile created as described above (step S607). A CMYK value that has been color-converted using the device link profile for saving mode may be referred to as a saving CMYK value.

  The CPU 11 calculates the sum of the CMYK values of all the pixels for the image data that has been subjected to color conversion using each profile as described above (step S608). That is, the CPU 11 calculates the sum of the CMYK values of all pixels for each of the normal mode, the saving mode is weak, the saving mode is in progress, and the saving mode is strong. At this time, each of the CMYK values may be multiplied by a predetermined coefficient. For example, when a cyan color material among CMYK color materials is expensive, the CMYK value is multiplied by 1.1, or when a black color material is inexpensive, CMYK. It may be 0.8 times the K value among the values.

  Next, the CPU 11 calculates a color material saving amount in each saving mode based on the sum of CMYK values in each saving mode (step S609). For example, if RIP development is performed at a resolution of 150 dpi on one page of A3 size paper, the number of pixels is 4349920 (1754 × 2480). When the CMYK values are 0 to 255, and the CMYK values of all the pixels are all 255, the total of the CMYK values is 44369918400 (43499920 pixels × 4 colors × 255). Here, for example, when a predetermined test image on a specific page (for example, the first page) of pages constituting a print job is formed on A3 size paper, the total of CMYK values in the normal mode is 109316890, When the sum of the CMYK values in the saving mode is 10384470546, the sum of the CMYK values in the saving mode is 98585425, and the sum of the CMYK values in the saving mode is 875554639, the reduction rate of the color material in each saving mode is It becomes 0.95 in the saving mode weak, 0.886 in the saving mode, and 0.801 in the saving mode strong. Expressing this in terms of color material saving amount, the saving mode is weak 5.0%, the saving mode 11.4%, and the saving mode strong 19.9.

Next, the CPU 11 calculates the average color difference between the normal mode and the saving mode for each saving mode (step S610). Specifically, the CPU 11 obtains the color difference between the pixels color-converted using the normal mode device link profile and the pixel color-converted using the saving mode device link profile for all the pixels, and these color differences. The average of is calculated. The average color difference is calculated for each saving mode. For the color difference, for example, the first LUT 100 created as described above is used, and the CMYK values that have been color-converted in the normal mode and the saving mode are converted into L ^* a ^* b ^* values, respectively. ^{* A *} b ^* can be obtained by taking the difference between values.

  Next, the CPU 11 acquires the maximum color difference between the normal mode and the saving mode for each saving mode (step S611). Specifically, the CPU 11 obtains, for each pixel, the color difference between the pixel that has been color-converted using the normal mode device link profile and the pixel that has been color-converted using the saving mode device link profile. Get things.

  As shown in FIG. 25, the CPU 11 puts the “weak” column indicating that the saving mode is weak, the “medium” column indicating that the saving mode is in progress, and the “strong” column indicating that the saving mode is strong as described above. The acquired color material saving amount, average color difference, and maximum color difference are displayed (step S612).

  Subsequently, the CPU 11 determines whether or not to execute printing (step S613). Specifically, as shown in FIG. 25, when printing in the saving mode is performed, after a check input is made to the check box CB2, one of the radio buttons RB1 to RB3 is input to save the mode. After selecting, printing is executed by operating the OK button B4. Further, when printing in the normal mode is performed, printing is executed by operating the OK button B4 after the check box CB2 is unchecked.

When the CPU 11 determines to execute printing (step S613: Y), the CPU 11 issues a print instruction in the selected mode (step S614), and then ends this process. On the other hand, when the CPU 11 does not determine to execute printing, that is, as shown in FIG. 25, when the cancel button B5 is operated and the print instruction is canceled (step S613: N), the process of step S614 is executed. This process is terminated without doing so.
In this embodiment, the color material saving amount can be estimated before printing in this way.

  In this embodiment, instead of the above-described color material saving amount estimation process, a color material saving amount notification process described below may be executed. In the present embodiment, for example, in the property screen as shown in FIG. 26, after a check input is made to the check box CB3, the saving mode is selected by inputting any of the radio buttons RB4 to RB6. be able to. If the check box CB3 is unchecked, the normal mode is selected. Further, in the present embodiment, information indicating the calculated color material saving amount and the like can be notified by sending an e-mail to a designated destination. Specifically, as shown in FIG. 26, after a check input is made to the check box CB4, an e-mail address is entered into the text box TB. After performing the input as described above, the print job is executed by operating the OK button B6. Note that when the cancel button B7 is operated, the print job is not executed.

  Next, color material saving amount notification processing using the saving mode weak device link profile, the saving mode medium device link profile, and the saving mode strong device link profile will be described with reference to FIG. This color material saving amount notification process is a process executed when the CPU 11 of the client PC 10 performs a print job, for example.

  First, the CPU 11 performs RIP rasterization on all pages of the print job at a resolution of 150 dpi and generates BMP image data (step S701).

  When the BMP image data is generated as described above, the CPU 11 performs color conversion on the image data into CMYK values using the normal mode device link profile generated as described above (step S702). ).

  Subsequently, the CPU 11 performs color conversion into CMYK values using a saving mode device link profile corresponding to the selected saving mode (step S703). Specifically, the CPU 11 performs color conversion using the device link profile for saving mode corresponding to the saving mode selected on the property screen shown in FIG.

The CPU 11 calculates the sum of the CMYK values of all the pixels for the image data that has been subjected to color conversion using each profile as described above (step S704).
Next, the CPU 11 calculates a color material saving amount in the selected saving mode based on the sum of the CMYK values in the selected saving mode (step S705).
Subsequently, the CPU 11 calculates the average color difference between the normal mode and the saving mode (step S706).
Subsequently, the CPU 11 obtains the maximum color difference between the normal mode and the saving mode (step S707).

The CPU 11 attaches the data file in which the information indicating the color material saving amount, the average of the color differences, and the maximum of the color differences acquired as described above is transmitted (step S708).
The CPU 11 ends the process after transmitting the mail with the data file attached to the designated mail address (step S709).

  As described above, according to the present embodiment, the CPU 11 acquires the normal CMYK value from the input image data using the color conversion table for converting the input image data into the CMYK value of the output device. The CPU 11 acquires a saved CMYK value in which the ratio of the CMY value to the CMYK value is smaller than the normal CMYK value of the input image data. Based on the acquired normal CMYK value and the saved CMYK value, the CPU 11 obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value, and performs control to notify the reduction amount in a recognizable manner. As a result, when the color material is saved while maintaining the color reproducibility, the saved amount of the color material can be accurately estimated.

  Further, according to the present embodiment, the CPU 11 performs control to select any one of the acquired normal CMYK values and saved CMYK values and form an image on a sheet based on the selected CMYK values. As a result, the amount of color material saved can be grasped and an image can be formed on a sheet by selecting from the normal mode and the saving mode.

  Further, according to the present embodiment, the CPU 11 acquires the normal CMYK value from the input image data using the color conversion table for converting the input image data into the CMYK value of the output device. The CPU 11 acquires a saved CMYK value in which the ratio of the CMY value to the CMYK value is smaller than the normal CMYK value of the input image data. The CPU 11 performs control to form an image on the sheet based on the acquired saving CMYK value, obtain a reduction amount of the saving CMYK value with respect to the normal CMYK value, and notify the reduction amount in a recognizable manner. As a result, when the color material is saved while maintaining the color reproducibility and the image is formed on the paper, the saved amount of the color material can be accurately estimated.

  In addition, according to the present embodiment, the CPU 11 performs control to form an image on the paper at the first resolution, and the saved CMYK value with respect to the normal CMYK value at the second resolution lower than the first resolution. Find the reduction amount. As a result, the processing time for estimating the saving amount can be shortened. Further, the memory capacity used for estimating the saving amount can be reduced.

  Further, according to the present embodiment, the CPU 11 represents the reduction amount of the saved CMYK value with respect to the normal CMYK value by the reduction rate of the CMYK value with respect to the normal CMYK value. As a result, the amount of color material saved can be recognized more easily.

  Further, according to the present embodiment, the CPU 11 obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value after multiplying each value of the saved CMYK value by a predetermined coefficient. As a result, the color material saving amount can be estimated in consideration of the color material cost, the amount of color material actually consumed, and the like.

  Further, according to the present embodiment, the CPU 11 inputs job data including a plurality of pages, and selects a page for which a reduction amount is to be obtained from the plurality of pages of the job data. CPU11 calculates | requires the reduction amount of the saving CMYK value with respect to normal CMYK value about the selected page. As a result, for example, it is possible to estimate a saving amount by selecting a page that is expected to save coloring materials, and therefore it is possible to reduce the processing time for estimating the saving amount and estimate the saving amount efficiently. become able to.

  Further, according to the present embodiment, the CPU 11 uses the color space conversion table for converting the input CMYK value in the output device to the output color value indicating the coordinates on the device-independent color space, and the normal CMYK value and Output color values are obtained from the saved CMYK values. The CPU 11 obtains a color difference that is a difference between the output color value obtained from the normal CMYK value and the output color value obtained from the saved CMYK value. The CPU 11 performs control to notify that the color difference is recognizable. As a result, the color reproduction accuracy can be recognized together with the estimation of the saving amount.

  Further, according to the present embodiment, the CPU 11 performs a control for obtaining a color difference for each pixel of the input image data and notifying the average of the color difference for each pixel so as to be recognized. As a result, the difference in overall color reproduction accuracy can be easily grasped.

  Further, according to the present embodiment, the CPU 11 performs a control to obtain a color difference for each pixel of the input image data and to notify the maximum one of the obtained color differences in a recognizable manner. As a result, it becomes possible to easily grasp the degree of difference in color reproduction accuracy.

  The description in the present embodiment is an example of the color adjustment system according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of each functional unit constituting the color adjustment system can be appropriately changed.

Further, in the present embodiment, a table such as various profiles is created in the client PC 10 and the processing for saving the color material is executed in the controller 2. You may comprise so that it may be performed by either one of PC and a controller.
In addition, each function of the client PC and the controller may be realized by a single device.
Further, the color printer may be configured to have the functions of the client PC and the controller.

  In the present embodiment, the color material saving amount is calculated in the client PC 10, but may be implemented in the controller 2.

  In the present embodiment, the maximum value is expressed as a value of 0 to 100% as an input value and an output value. However, the maximum value is set to 255, which is a maximum value of 1 byte, and is 0 to 255. It may be expressed by a value.

In this embodiment, the present invention can be applied to various color printers such as an electrophotographic system and an inkjet system.
In this embodiment, a CMYK four-color printer is used. However, the present invention may be applied to a color printer including other color materials such as light cyan and light magenta.

  In the present embodiment, various tables such as profiles created in the client PC 10 are stored in the storage unit 16 of the client PC 10 and the table necessary for color conversion is held in the controller 2. A part or all of the created various tables may be stored in the controller 2.

  In the present embodiment, the CMYK color data that does not save the color material is not subjected to the process for saving the color material, and the color printer is based on the CMYK value obtained by the normal color conversion process. The processing for saving the color material may be performed on the CMYK color data which is output according to 1 but does not save the color material. For example, for CMYK values that do not save color material, a color adjustment table may be configured so that the output CMYK values do not change.

  In this embodiment, the color adjustment system 1000 that inputs RGB color image data and obtains CMYK values is employed. However, a color adjustment system that inputs CMYK color image data and obtains CMYK values may be used. Alternatively, both RGB image data and CMYK color image data may be input.

  In the present embodiment, the color material is saved by decreasing the CMY components and increasing the K components by the color adjustment table in which the total amount of the K plate generation curve and the CMYK components is limited. However, the color material may be saved by using only one of the K plate generation curve and the color adjustment table in which the total amount of each component of CMYK is limited.

  In the present embodiment, a device link profile is created in normal color conversion processing, and color conversion and color material savings are calculated using this, but the device link profile is not created, Color conversion and color material saving amount may be calculated using the destination profile.

  In the present embodiment, a color adjustment table is created based on the first LUT and the third LUT, and color adjustment is performed using the table. However, the color adjustment table is not created, and the first LUT is not created. And the third LUT may be used for color adjustment.

  In the present embodiment, the color material reduction rate, which is the ratio of the sum of the CMYK values in the saving mode to the sum of the CMYK values in the normal mode, is obtained, and the color material saving amount is displayed based on this. The color material reduction rate may be displayed instead of the color material saving amount. Further, the sum of the CMYK values in the normal mode and the sum of the CMYK values in the saving mode may be displayed in a comparable manner.

  In the present embodiment, the average of the color difference between the normal mode and the saving mode and the maximum of the color difference are obtained and displayed, but these may not be displayed.

  In the present embodiment, the color material saving amount is obtained for all pages or a part of pages of the print job. However, the present invention is not limited to this, and for example, JPEG (Joint Photographic Experts Group) format or TIFF A color material saving amount may be obtained for an image file of the (Tagged Image File Format) format or the like.

In this embodiment, the color material reduction rate and the saving amount for the total of CMYK values are obtained. However, the color material reduction rate and saving for the total of one or more colors of CMYK. The amount may be obtained. For example, the color material saving amount may be obtained from the sum of the CMY values in the saving mode relative to the sum of the CMY values in the CMYK values in the normal mode.
Further, the total of two or more colors of CMYK may be obtained for each color, and the reduction rate and the saving amount of the color material for each color may be obtained.

  In the present embodiment, an example in which a hard disk, a semiconductor nonvolatile memory, or the like is used as a computer-readable medium for the program according to the present invention is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also used as a medium for providing program data according to the present invention via a communication line.

1000 Color adjustment system 1 Color printer 2 Controller 10 Client PC
11 CPU

Claims (28)

A normal CMYK value is acquired from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value is greater than the normal CMYK value of the input image data. Control for obtaining a reduced saved CMYK value, obtaining a reduction amount of the saved CMYK value with respect to the normal CMYK value based on the obtained normal CMYK value and the saved CMYK value, and recognizing the reduction amount in a recognizable manner. With a control unit to perform ,
The control unit outputs from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. Each of the color values is obtained, a color difference that is a difference between the output color value obtained from the normal CMYK value and the output color value obtained from the saved CMYK value is obtained, and control for notifying the color difference is performed . Characteristic color adjustment device.   The control unit selects one of the acquired normal CMYK value and the saved CMYK value, and performs control to form an image on a sheet based on the selected CMYK value. The color adjusting apparatus according to 1. A normal CMYK value is acquired from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value rather than the normal CMYK value of the input image data Obtains the saved CMYK value with reduced, forms an image on the paper based on the obtained saved CMYK value, obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value, and informs the reduction amount so that it can be recognized A control unit for performing control ,
The control unit outputs from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. Each of the color values is obtained, a color difference that is a difference between the output color value obtained from the normal CMYK value and the output color value obtained from the saved CMYK value is obtained, and control for notifying the color difference is performed . Characteristic color adjustment device.   The control unit performs control to form an image on a sheet at a first resolution, and obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value at a second resolution lower than the first resolution. The color adjusting apparatus according to claim 2 or 3, characterized in that:   5. The color according to claim 1, wherein the control unit represents a reduction amount of the saving CMYK value with respect to the normal CMYK value by a reduction rate of the CMYK value with respect to the normal CMYK value. Adjustment device.   6. The control unit according to claim 1, wherein the control unit obtains a reduction amount of the saving CMYK value with respect to the normal CMYK value after multiplying each value of the saving CMYK value by a predetermined coefficient. The color adjusting apparatus according to one item.   The control unit inputs job data including a plurality of pages, selects a page for which a reduction amount is to be obtained from the plurality of pages of the job data, and reduces the saved CMYK value with respect to the normal CMYK value for the selected page. The color adjustment device according to claim 1, wherein an amount is obtained. Wherein the control unit obtains the color difference for each pixel of the input image data, according to any one of claims 1 to 7, characterized in that the recognizable control for notifying the average of the color difference of the pixel Motogoto Color adjustment device. The control unit according to claim 1, wherein the control unit obtains a color difference for each pixel of the input image data, and performs control for recognizing a maximum one of the color differences obtained for each pixel . The color adjusting device according to any one of the above. A normal CMYK value acquisition step of acquiring normal CMYK values from input image data using a color conversion table for converting input image data into CMYK values of an output device;
A saving CMYK value acquisition step of acquiring a saving CMYK value in which a ratio of the CMY value to the CMYK value is smaller than the normal CMYK value of the input image data;
A reduction amount acquisition step for obtaining a reduction amount of the saving CMYK value with respect to the normal CMYK value based on the normal CMYK value and the saving CMYK value acquired in the normal CMYK value acquisition step and the saving CMYK value acquisition step;
A notification step of recognizing the reduction amount obtained in the reduction amount acquisition step in a recognizable manner;
An output color value is obtained from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. A color difference notification step of obtaining a color difference that is a difference between an output color value obtained from the normal CMYK value and an output color value obtained from the saved CMYK value, and recognizing the color difference in a recognizable manner;
A color adjustment method comprising: An image forming step of selecting one of the normal CMYK value and the saved CMYK value acquired in the normal CMYK value acquisition step and the saving CMYK value acquisition step, and forming an image on a sheet based on the selected CMYK value The color adjustment method according to claim 10 , further comprising: A normal CMYK value acquisition step of acquiring normal CMYK values from input image data using a color conversion table for converting input image data into CMYK values of an output device;
A saving CMYK value acquisition step of acquiring a saving CMYK value in which a ratio of the CMY value to the CMYK value is smaller than the normal CMYK value of the input image data;
An image forming step of forming an image on a sheet based on the saved CMYK value acquired in the saved CMYK value acquisition step;
A reduction amount acquisition step for obtaining a reduction amount of the saving CMYK value with respect to the normal CMYK value based on the normal CMYK value and the saving CMYK value acquired in the normal CMYK value acquisition step and the saving CMYK value acquisition step;
A notification step of recognizing the reduction amount obtained in the reduction amount acquisition step in a recognizable manner;
An output color value is obtained from the normal CMYK value and the saved CMYK value using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. A color difference notification step of obtaining a color difference that is a difference between an output color value obtained from the normal CMYK value and an output color value obtained from the saved CMYK value, and recognizing the color difference in a recognizable manner;
A color adjustment method comprising: In the image forming step, control is performed to form an image on the paper at the first resolution,
The color adjustment method according to claim 11 or 12 , wherein, in the reduction amount acquisition step, a reduction amount of the saved CMYK value with respect to the normal CMYK value is obtained with a second resolution lower than the first resolution. The color according to any one of claims 10 to 13 , wherein, in the notification step, a reduction amount of the saving CMYK value with respect to the normal CMYK value is represented by a reduction rate of the CMYK value with respect to the normal CMYK value. Adjustment method. In the reduction amount acquisition step, of claims 10 to 14, wherein the determination of the reduction amount of the savings CMYK values for the normal CMYK value after multiplied by a predetermined coefficient respectively for each value of the savings CMYK values The color adjustment method according to any one of the above. A page selection step of inputting job data consisting of a plurality of pages and selecting a page for which a reduction amount is to be calculated from the plurality of pages of the job data,
In the reduction amount acquisition step, according to any one of claims 10 to 15, wherein the determination of the reduction amount of the savings CMYK values for the normal CMYK values for the selected page in the page selection process Color adjustment method. The color according to any one of claims 10 to 16, wherein in the color difference notification step, a color difference is obtained for each pixel of the input image data, and an average of the color difference for each pixel is notified so as to be recognizable. Adjustment method. The color difference notifying step obtains a color difference for each pixel of the input image data, and informs the maximum of the color differences obtained for each pixel so as to be recognizable . The color adjustment method according to one item . Computer
A normal CMYK value is acquired from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value is greater than the normal CMYK value of the input image data. Control for obtaining a reduced saved CMYK value, obtaining a reduction amount of the saved CMYK value with respect to the normal CMYK value based on the obtained normal CMYK value and the saved CMYK value, and recognizing the reduction amount in a recognizable manner. There line,
Further, an output color value is obtained from the normal CMYK value and the saved CMYK value by using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. respectively obtained, the normal determined color difference is a difference between the output color value obtained from the savings CMYK value and the output color value obtained from the CMYK values, function control of recognizably notifying the color difference as a line intends control means Color adjustment program to make. The color according to claim 19 , wherein the control unit selects a CMYK value of the acquired normal CMYK value or the saved CMYK value, and performs control to form an image on a sheet based on the selected CMYK value. Adjustment program. Computer
A normal CMYK value is obtained from the input image data using a color conversion table for converting the input image data into the CMYK value of the output device, and the ratio of the CMY value to the CMYK value relative to the normal CMYK value of the input image data. Is obtained, and an image is formed on the sheet based on the obtained saved CMYK value, a reduction amount of the saved CMYK value with respect to the normal CMYK value is obtained, and the reduction amount is recognizable and notified. control stomach line,
Further, an output color value is obtained from the normal CMYK value and the saved CMYK value by using a color space conversion table for converting an input CMYK value in the output device into an output color value indicating coordinates in a device-independent color space. respectively obtained, the normal determined color difference is a difference between the output color value obtained from the savings CMYK value and the output color value obtained from the CMYK values, function control of recognizably notifying the color difference as a line intends control means Color adjustment program to make. The control unit performs control to form an image on a sheet at a first resolution, and obtains a reduction amount of the saved CMYK value with respect to the normal CMYK value at a second resolution lower than the first resolution. The color adjustment program according to 20 or 21 . The color adjustment program according to any one of claims 19 to 22 , wherein the control means represents a reduction amount of the saving CMYK value with respect to the normal CMYK value by a reduction rate of the CMYK value with respect to the normal CMYK value. Wherein, according to any one of claims 19-23 for determining the reduction amount of the savings CMYK values for the normal CMYK value after multiplied by a predetermined coefficient respectively for each value of the savings CMYK values Color adjustment program. The control means inputs job data consisting of a plurality of pages, selects a page for which a reduction amount is to be obtained from the plurality of pages of the job data, and reduces the saved CMYK value with respect to the normal CMYK value for the selected page The color adjustment program according to any one of claims 19 to 24 , wherein the amount is obtained. The color adjustment program according to any one of claims 19 to 25, wherein the control unit performs control for obtaining a color difference for each pixel of the input image data and reporting the average of the color difference for each pixel so as to be recognizable. 26. The control unit according to any one of claims 19 to 25, wherein the control unit obtains a color difference for each pixel of the input image data, and performs control for recognizing a maximum one of the color differences obtained for each pixel. The described color adjustment program. A computer-readable medium storing the color adjustment program according to any one of claims 19 to 27 .

Images