JP2017195485A - Color correction apparatus and color correction method, and color correction program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in color accuracy in performing color correction using a correction table.SOLUTION: A color correction apparatus comprises: an information acquisition unit for acquiring machine state information on a color image output apparatus; a history management unit that on the basis of a color value obtained by performing color measurement using a colorimeter on a color chart output by the color image output apparatus, determines a correction amount for an output device value for the color chart, creates a correction table including a correction amount described for each input color, and stores the correction table in association with the machine state information; and a correction control unit that in instructing the color image output apparatus to output a color image, estimates a correction amount in the present machine state of the color image output apparatus on the basis of the stored correction table, and uses the estimated correction amount to correct an output device value for the color image. The correction control unit, in estimating a correction amount, determines whether the correction amount is singular data, for each input color; and does not use the correction amount determined to be singular data, for correction of the output device value for the color image.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a color correction apparatus, a color correction method, and a color correction program, and in particular, a color correction apparatus that performs color correction using a correction table, a color correction method in a printing system including the color correction apparatus, and the color correction apparatus. The present invention relates to a color correction program that operates.

  When outputting a color image using a color image output device, it is necessary to convert a device value (input device value) on the image data into a device value (output device value) of the color image output device. A conversion table (for example, a device link profile) is used. The input device value has a desired color (for example, a color value), and the color conversion table converts the input device value into an output device value corresponding to the desired color. The color image output apparatus outputs a color image in accordance with the output device value thus converted.

  If the color of the output color image is the same as the desired color, there is no problem, but in reality, the machine status of the color image output device (the usage time of each component constituting the print engine, the environmental humidity and environment of the print engine) Since the output color image changes depending on the temperature or the like, a desired color cannot be reproduced only with the color conversion table. Therefore, a correction table for correcting the output device value is used so that the output color image has a desired color. This correction table is a table describing a correction amount for correcting an output device value according to an input device value (that is, converting an output device value into a corrected output device value).

  As a technique relating to such color correction, for example, Patent Document 1 discloses an image processing apparatus capable of performing correction processing for correcting gradation fluctuations in an image printed on a recording medium, and In the processing, gradation comparison determination means for determining whether or not the gradation of the image printed on the recording medium is within a reference range, and whether or not there is an abnormality in colorimetry of the image printed on the recording medium Based on the determination results of the colorimetric determination unit, the gradation comparison determination unit, and the colorimetry determination unit, at least the cause of the gradation variation relates to the correction process or the image A configuration is disclosed that includes display means for displaying a message indicating whether the image output means is for printing on a recording medium.

  Further, Patent Document 2 uses a color conversion unit that describes the color reproduction characteristics of a color input / output device, so that the device-dependent first color space and the device-independent second color space are mutually connected. An image processing method for performing color conversion, which is configured to refer to correction history information for a predetermined color when the color conversion unit is corrected so that a predetermined color of the input image and the output image of the color match each other. Has been.

JP 2014-175861 A JP 2004-004369 A

  By using the color conversion table and the correction table, the output color image can reproduce a desired color. However, as described above, the output color image varies depending on the machine state of the color image output device. The correction table also needs to be appropriately corrected according to the machine state.

  As a method for this, a method is conceivable in which a correction table corresponding to the machine state is stored as history information, and the correction table stored as the history information is corrected according to the machine state when a color image is output. At this time, since the correction table corrects the output device value according to the machine state, the correction table should be usable even if the color conversion table changes according to the change of the paper type used for printing. is there. However, when the correction table stored as history information includes the correction amount of the output device value depending on the specific color conversion table, when using another color conversion table such as a newly created color conversion table If this correction table is applied, there is a problem that the color accuracy may deteriorate.

  The present invention has been made in view of the above-described problems, and its main object is to provide a color correction apparatus, a color correction method, and a color that can prevent deterioration of color accuracy in color correction using a correction table. It is to provide a correction program.

  One aspect of the present invention is a color correction device that corrects an output device value of a color image output device converted from an input device value using a color conversion table according to a machine state of the color image output device, An information acquisition unit that acquires machine state information for specifying a machine state of the color image output device, and a color chart obtained by measuring the color chart output from the color image output device with a colorimeter. A correction amount of the output device value corresponding to the input device value is determined, a correction table describing the correction amount for each input color is created, and the correction table is associated with the machine state information as history information in the storage unit The history management unit to be stored and the color image output device with reference to the stored correction table when instructing the color image output device to output a color image A correction control unit that estimates a correction amount for each input color in the current machine state and corrects an output device value corresponding to the input device value of the color image using the estimated correction amount for each input color. The correction control unit determines whether the correction amount is singular data for each input color when estimating the correction amount, and the correction amount determined to be the singular data is used to correct the output device value. It is not used.

  One aspect of the present invention provides a color correction device that corrects an output device value of a color image output device converted from an input device value using a color conversion table according to a machine state of the color image output device, and the color A color correction method in a printing system including an image output device and a colorimeter, wherein the color correction device receives machine state information for specifying a machine state of the color image output device from the color image output device. Based on the acquired first color processing, second color processing for measuring color values measured by the color image output device from the colorimeter, and the acquired color values. A third process for determining a correction amount of the output device value corresponding to the input device value and creating a correction table describing the correction amount for each input color; and A fourth process for storing the history information in the storage unit in association with the state information, and referring to the stored correction table when instructing the color image output apparatus to output a color image, the color image output apparatus A fifth process of estimating a correction amount in the current machine state for each input color, and correcting an output device value corresponding to the input device value of the color image using the estimated correction amount for each input color. In the fifth process, when the correction amount is estimated, it is determined whether the correction amount is singular data for each input color, and the correction amount determined as the singular data is the output device value. It is not used for correction.

  One aspect of the present invention is a color that operates in a color correction device that corrects an output device value of a color image output device converted from an input device value using a color conversion table in accordance with a machine state of the color image output device. A correction program comprising: a first process for acquiring machine state information for specifying a machine state of the color image output device from the color image output device; and the color image output device from a colorimeter. A second process for acquiring a color value obtained by measuring the color chart output from the color chart, determining a correction amount of the output device value corresponding to the input device value of the color chart based on the acquired color value, and for each input color A third process for creating a correction table in which the correction amount is described, and a fourth process for storing the correction table in the storage unit as history information in association with the machine state information When instructing the color image output device to output a color image, the correction amount in the current machine state of the color image output device is estimated for each input color with reference to the stored correction table, and the estimated input A fifth process for correcting an output device value corresponding to an input device value of the color image using the correction amount for each color, and in the fifth process, when the correction amount is estimated, It is determined whether the correction amount is singular data every time, and the correction amount determined to be the singular data is not used for correcting the output device value.

  According to the color correction apparatus, the color correction method, and the color correction program of the present invention, it is possible to prevent the color accuracy from being deteriorated during color correction using the correction table.

  The reason is that the color correction device (color correction program) acquires the machine state information of the color image output device, and based on the color values obtained by measuring the color chart output from the color image output device with the colorimeter. The correction amount of the output device value corresponding to the input device value is determined, a correction table describing the correction amount for each input color is created, the correction table is stored as history information in association with the machine state information, and the color image When the output device is instructed to output a color image, the correction amount in the current machine state of the color image output device is estimated for each input color with reference to the stored correction table, and the color image is calculated using the estimated correction amount. The output device value corresponding to the input device value is corrected. Then, when estimating the correction amount, it is determined whether the correction amount is singular data for each input color, and the correction amount determined to be singular data is controlled not to be used for correcting the output device value of the color image. Because.

1 is a schematic diagram illustrating an example of a configuration of a printing system according to an embodiment of the present invention. It is a schematic diagram which shows the other example of a structure of the printing system which concerns on one Example of this invention. It is a block diagram which shows the structure of the client terminal which concerns on one Example of this invention. It is a block diagram which shows the structure of the controller which concerns on one Example of this invention. 1 is a block diagram illustrating a configuration of a color image output apparatus according to an embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a configuration of a print processing unit of a color image output apparatus according to an embodiment of the present invention. It is a flowchart figure which shows the process (history accumulation | storage process) of the color image output device which concerns on one Example of this invention. It is a flowchart figure which shows the process (history operation process) of the color image output device which concerns on one Example of this invention. It is a flowchart figure which shows the process (estimation process of a correction amount) of the color image output device which concerns on one Example of this invention. It is a table which shows the relationship between the machine state of the input color A which concerns on one Example of this invention, and a correction amount. It is a table which shows the tendency value for every input color which concerns on one Example of this invention. It is a table which shows the example of determination using the difference of the tendency value for every input color which concerns on one Example of this invention. It is a figure explaining the relationship between a correction amount, a tendency value, and a whole tendency value.

  As shown in the background art, when a color image is output using a color image output device, a device value (input device value) on the image data is converted into a device value (output device) of the color image output device using a color conversion table. Value), and further, the output device value is corrected using the correction table, so that the output color image has a desired color.

  At this time, since the output color image varies depending on the machine state of the color image output device (the usage time of each member constituting the print engine, the environmental humidity and the environmental temperature of the print engine, etc.), the correction table also depends on the machine state. It is necessary to correct it appropriately. Therefore, a method is used in which a correction table corresponding to the machine state is stored as history information, and the correction table stored as the history information is corrected according to the machine state when a color image is output. However, if the correction table saved as history information includes the correction amount of the output device value that depends on the specific color conversion table, applying this correction table when using another color conversion table will The accuracy may deteriorate.

  The correction amount of the output device value that depends on this specific color conversion table is, for example, a color value due to a problem in a specific patch when a color chart for creating a specific color conversion table is measured. Becomes an inappropriate value, and as a result, the correction amount for correcting the output device value converted using the color conversion table becomes an inappropriate value (hereinafter referred to as singular data). When this correction amount is applied to an output device value converted using a color conversion table (for example, a color conversion table newly created corresponding to a different paper type), the corrected output device value becomes a desired value. It will be out of color.

  Therefore, in one embodiment of the present invention, the machine state of the color image output device and the correction table are associated and accumulated as history information, and when using the accumulated history information, each input color of the accumulated correction table is stored. Was determined based on whether the difference between the trend value of the correction amount of the input color and the overall trend value exceeds a predetermined threshold, and was not determined to be singular data. In this case, the correction amount in the current machine state is estimated using the correction amount of the input color, and if it is determined as singular data, the correction amount of the input color is not used for color correction, and input other than the input color is input. The correction amount in the current machine state is estimated using the correction amount of the color (for example, the input color close to the input color).

  In this way, it is determined whether or not the correction amount of the correction table stored as history information is singular data. In the case of singular data, the singular data is not used for color correction. Thus, even when color correction is performed using history information, deterioration of color accuracy can be avoided.

  In order to describe the above-described embodiment of the present invention in more detail, a color correction apparatus, a color correction method, and a color correction program according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 are schematic diagrams showing the configuration of the printing system of this embodiment, FIG. 3 is a block diagram showing the configuration of the client terminal, and FIG. 4 is a block diagram showing the configuration of the controller. 5 is a block diagram showing the configuration of the color image output device, FIG. 6 is a schematic diagram showing the configuration of the print processing unit of the color image output device, and FIGS. 7 to 9 are diagrams of the color image output device. It is a flowchart figure which shows a process. 10 to 12 are examples of tables used to determine whether or not the correction amount is singular data. FIG. 13 is a diagram for explaining the relationship among the correction amount, the trend value, and the overall trend value. It is.

  As shown in FIG. 1, in the printing system of this embodiment, a client terminal 10, a controller 20, a color image output device 30, and a colorimeter 40 that can be connected via a communication network 50 are arranged on an intranet. Ethernet (registered trademark) or the like can be used as the standard of the communication network 50, but the data transfer from the controller 20 to the color image output device 30 can also use IEEE1394, Parallel, etc. in addition to Ethernet (registered trademark). It is.

  In FIG. 1, the controller 20 and the color image output device 30 are separate devices. However, as shown in FIG. 2, the color image output device 30 may include the controller 20. Hereinafter, each device will be described in detail on the assumption of the configuration of FIG.

[Client terminal]
The client terminal 10 is a computer device such as a personal computer, and creates a print job and transmits it to the controller 20. As shown in FIG. 3A, the client terminal 10 includes a control unit 11, a storage unit 12, a network I / F unit 13, a display unit 14, an operation unit 15, and the like.

  The control unit 11 includes a CPU (Central Processing Unit) 11a and a memory such as a ROM (Read Only Memory) 11b and a RAM (Random Access Memory) 11c. The CPU 11a stores a control program stored in the ROM 11b or the storage unit 12. The operation of the entire client terminal 10 is controlled by expanding and executing in the RAM 11c. As shown in FIG. 3B, the control unit 11 (CPU 11a) executes an OS (Operating System) 16, a document creation application 17, a printer driver 18, and the like.

  The OS 16 is Windows (registered trademark), Mac OS (registered trademark), Android (registered trademark), or the like, and enables the client terminal 10 to operate the document creation application 17 and the printer driver 18.

  The document creation application 17 is software that performs text creation, spreadsheet calculation, image processing, and the like. The document creation application 17 reads the printer driver 18 when printing is instructed, and transfers document data created by the document creation application 17 to the printer driver 18.

  The printer driver 18 converts the document data created by the document creation application 17 into a page description language such as a print job (PJL (Printer Job Language), PS (PostScript), or PCL (Printer Control Language)) in a language that the controller 20 can interpret. In PDL (Page Description Language) data or PDF (Portable Document Format) data). To this print job, image forming conditions set in the print setting screen of the printer driver 18 (in this embodiment, information for specifying a color conversion table, a correction table, etc.) are described in a print ticket, a header, and the like. The

  The storage unit 12 is configured by an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like, and a program for the CPU 11a to control each unit, information on processing functions of the own apparatus, and manuscript data created by the document creation application 17 The print job created by the printer driver 18 is stored.

  The network I / F unit 13 includes a NIC (Network Interface Card), a modem, and the like, connects the client terminal 10 to the communication network 50, and transmits a print job to the controller 20.

  The display unit 14 includes a liquid crystal display (LCD), an organic EL (electroluminescence) display device, and the like, and displays a document creation screen of the document creation application 17, a print setting screen of the printer driver 18, and the like.

  The operation unit 15 includes a mouse, a keyboard, and the like, and enables operations such as document creation by the document creation application 17 and setting of printing conditions by the printer driver 18.

[controller]
The controller 20 is a color correction device that controls the color image output device 30. As shown in FIG. 4A, the controller 20 includes a control unit 21, a storage unit 22, an image processing unit 23, a RIP (Raster Image Processor) unit 24, a network I / F unit 25, and a printer I / F unit 26. And a display unit and an operation unit (not shown) as necessary.

  The control unit 21 includes a CPU 21a and a memory such as a ROM 21b and a RAM 21c. The CPU 21a controls the operation of the entire controller 20 by developing the control program stored in the ROM 21b and the storage unit 22 in the RAM 21c and executing it. To do.

  The storage unit 22 is configured by an HDD, an SSD, or the like, and includes a program for the CPU 21a to control each unit, a print job received from the client terminal 10, image data generated based on the print job, and a color conversion table (for color conversion). Device link profile), correction table, various tables used for determining whether the correction amount of the correction table is singular data, machine state information of the color image output device 30, and the like are stored.

  The image processing unit 23 analyzes a processing method of print jobs (for example, PDL data) received from the client terminal 10 and various image generation instructions.

  The RIP unit 24 is configured by an image processing ASIC (Application Specific Integrated Circuit) or the like, translates the PDL data, rasterizes each page of the document, and generates bitmap format image data. At this time, an input device value (for example, RGB value) is converted into an output device value (for example, CMYK value) using a color conversion table.

  The network I / F unit 25 includes a NIC, a modem, and the like, connects the controller 20 to the communication network 50, and receives a print job and the like from the client terminal 10. The printer I / F unit 26 is a dedicated interface for connecting the controller 20 to the color image output device 30. The printer I / F unit 26 receives machine state information from the color image output device 30, or receives a bitmap format in the color image output device 30. Send image data and give output instructions.

  Further, as shown in FIG. 4B, the control unit 21 also functions as an information acquisition unit 27, a history management unit 28, a correction control unit 29, and the like.

  The information acquisition unit 27 is a measurement unit provided in the color image output device 30 (for example, a timer for measuring the usage time of each member (for example, a photoconductor) constituting a print control unit (printing engine) to be described later or environmental humidity. / Information from which the machine state of the color image output device 30 such as the usage time, environmental humidity, and environmental temperature of each member is specified (referred to as machine state information). The machine status information is notified to the history management unit 28 and the correction control unit 29.

  The history management unit 28 creates / corrects a correction table corresponding to the machine state of the color image output device 30. When creating a correction table, the color image output device 30 prints a color chart obtained by converting the color value of the input color on the image data of each patch into an output device value using the color conversion table, and the printing system Correct the output device value corresponding to the input device value of the color chart from the amount of deviation between the color value obtained by measuring the color of the color chart by the colorimeter 40 arranged and the predetermined authentication standard. The amount is determined, a correction table describing the correction amount for each input color is created, and the created correction table is associated with the machine state information acquired by the information acquisition unit 27 and stored as history information in the storage unit 22 or the like. . When correcting the correction table, the color value (input device value) of the input color on the image data of each patch is converted into an output device value using the color conversion table, and further corrected using the correction table. The color chart is printed on the color image output device 30, and the colorimeter 40 is used to measure the color chart, and the input value of the color chart is obtained from the amount of deviation between the color value obtained by measuring each patch and the certification standard. The correction amount of the corresponding output device value is determined, the determined correction amount is reflected and corrected in the correction table, and the corrected correction table is stored as history information in association with the machine state information acquired by the information acquisition unit 27. Stored in the unit 22 or the like. Further, the history management unit 28 creates a correction table based on the correction values estimated by the correction control unit 29 in a procedure described later, and associates the created correction table with the machine state information acquired by the information acquisition unit 27. The history information is stored in the storage unit 22 or the like. Further, the history management unit 28 recreates the color conversion table in accordance with an instruction from the correction control unit 29.

  When instructing the output of the color image, the correction control unit 29 determines whether the correction amount of the correction table is singular data for each input color. Specifically, for each input color, the correction amount (ΔC, ΔM, ΔY, ΔK) in each machine state is corrected to a predetermined color space (eg, ΔL *, Δa *) so that the appearance of the color can be determined. , Δb *), set the average color space correction value as the trend value for the input color, set the average trend value for each input color as the overall trend value, and set the trend value for each input color and the overall When the difference from the tendency value exceeds a predetermined threshold, it is determined that the input color correction amount is singular data. If the predetermined input color correction amount is not singular data, the correction amount (a part or all of the predetermined input color correction amount) is used to determine the correction amount in the current machine state of the color image output device 30. If the estimated input color correction amount is singular data, the correction amount is not used for color correction, and an input color other than the predetermined input color (for example, an input color close to the predetermined input color) is used. The correction amount in the current machine state of the color image output device 30 is estimated using the correction amount. Then, the output device value corresponding to the input device value of the color image is corrected using the estimated correction amount. Further, when the number of correction amounts determined to be singular data exceeds a predetermined amount or ratio, the correction control unit 29 determines that the color conversion table serving as a reference for creating the correction table is abnormal, The history management unit 28 is instructed to recreate the color conversion table.

  The information acquisition unit 27, the history management unit 28, and the correction control unit 29 may be configured as hardware, or a color that causes the control unit 21 to function as the information acquisition unit 27, the history management unit 28, and the correction control unit 29. It may be configured as a correction program so that the CPU 21a executes the color correction program.

[Color image output device]
The color image output apparatus 30 is an image forming apparatus such as an MFP (Multi-Functional Peripherals) that performs printing based on an instruction from the controller 20. As shown in FIG. 5A, the color image output device 30 includes a control unit 31, a storage unit 32, a controller I / F unit 33, a panel operation unit 34, an image reading unit 35, a print processing unit 36, and the like. Is done.

  The control unit 31 includes a CPU 31a and a memory such as a ROM 31b and a RAM 31c. The CPU 31a controls the overall operation of the color image output apparatus 30 by developing and executing a control program stored in the ROM 31b on the RAM 31c. .

  The storage unit 32 is configured by an HDD, an SSD, or the like, and stores a program for the CPU 31a to control each unit, image data received from the controller 20, machine state information of the color image output device 30, and the like. As will be described later, when the control unit 31 functions as a history management unit and a correction control unit, the color conversion table (device link profile) used for color conversion, the correction table, and the correction amount of the correction table are singular data. Various tables used to determine whether or not are stored.

  The controller I / F unit 33 is a dedicated interface for connecting the color image output device 30 to the controller 20, and transmits machine state information to the controller 20 and receives image data from the controller 20.

  The panel operation unit 34 is a touch panel in which an operation unit such as a touch sensor made of a grid-like transparent electrode is formed on a display unit such as an LCD, and displays various screens related to printing and various operations related to printing. To.

  The image reading unit 35 is a part that optically reads image data from a document placed on a document table, and a light source that scans the document and a CCD (Charge Coupled) that converts light reflected by the document into an electrical signal. Devices) and an A / D converter for A / D converting electrical signals.

  The print processing unit 36 is a print engine that forms an image using CMYK toner (photoconductor) based on the image data received from the controller 20. Specifically, as shown in the schematic diagram of FIG. 6, an electrostatic latent image is formed by irradiating the photosensitive drum charged by the charging unit with light corresponding to the image from the exposure unit, and charged by the developing unit. The toner image is developed with the toner adhered, and the toner image is primarily transferred to the intermediate belt by the primary transfer roller, and is secondarily transferred from the intermediate belt to the sheet by the secondary transfer roller, and the toner image on the sheet is further transferred by the fixing unit. A fixing process is performed.

[Colorimeter]
The colorimeter 40 is a spectral colorimeter (spectrophotometer) capable of measuring for each wavelength of light, and measures each patch of the color chart output from the color image output device 30 to obtain a color value. Output.

  1 to 5 show an example of the printing system of the present embodiment, and the configuration and control of each device can be changed as appropriate.

  For example, in the above description, the controller 20 performs color conversion and color correction using the color conversion table and the correction table. However, when the color image output apparatus 30 includes the controller 20 as in the printing system of FIG. The image output apparatus 30 may be operated as a color correction apparatus, and the color image output apparatus 30 may perform color correction (or color conversion and color correction) using a correction table (or color conversion table and correction table). . In this case, as shown in FIG. 5B, the control unit 31 of the color image output device 30 is caused to function as an information acquisition unit 37, a history management unit 38, and a correction control unit 39 (the CPU 31a of the color image output device 30 is made to function). The color correction program is executed). In the above description, only color correction is performed as correction. However, the color image output apparatus 30 may separately perform correction other than color correction.

  In FIG. 1 and FIG. 2, the color measuring device 40 is arranged in the printing system. However, instead of the color measuring device 40, the print processing unit 36 of the color image output device 30 is used in the same manner as the external color measuring device 40. Alternatively, a spectrum-type inline colorimeter capable of measuring each wavelength of light may be provided, and the inline colorimeter may measure a color chart and output a color value.

  The operation of the color image output device 30 (color image output device 30 incorporating the controller 20) in the printing system of FIG. 2 will be described below. The CPU 31a executes the process of each step shown in the flowcharts of FIGS. 7 to 9 by developing and executing the color correction program stored in the ROM 31b or the storage unit 32 in the RAM 31c. In the following description, the control unit 31 of the color image output device 30 is caused to function as the information acquisition unit 37, the history management unit 38, and the correction control unit 39, and the correction control unit 39 applies the color conversion table and the correction table. It is assumed that color conversion and color correction are performed, and the storage unit 32 stores a color correction program, a color conversion table, a correction table, various tables used for determining whether the correction amount is singular data, and the like. And

[History accumulation processing]
First, the history accumulation process will be described with reference to FIG. When the control unit 31 (correction control unit 39) of the color image output apparatus 30 receives an output instruction of a color confirmation chart (for example, an IT8.7-4 chart defined by the Japan Color authentication system) (S101), Applying a color conversion table (a device link profile for reproducing the color value defined in the authentication standard) stored in advance to the color value of the input color of each patch of the color confirmation chart is output. The device value is converted (S102), and then the correction table is applied to convert it to a correction output device value (S103). The print processing unit 36 then outputs a color confirmation chart based on the corrected output device value (S104).

  Next, the control unit 31 (history management unit 38) obtains a color value obtained by measuring the color confirmation chart from an external colorimeter 40 or an inline colorimeter provided in the color image output device 30 ( S105) It is confirmed whether the acquired color value is a desired color (for example, whether it is within the Japan Color certification standard) (S106). When the acquired color value does not fall within the authentication standard, the control unit 31 (history management unit 38) determines a correction amount from the colorimetric color value and the amount of deviation of the authentication standard, and the determined correction amount is corrected in the correction table. (S107), the process returns to S101 and the same processing is repeated.

  On the other hand, when the acquired color value falls within the authentication standard, the control unit 31 (information acquisition unit 37) displays the current machine status information of the color image output device 30 (particularly members constituting the print processing unit 36 (particularly, , The usage time of the photosensitive member, the environmental humidity and the environmental temperature of the print processing unit 36) (S108), and the control unit 31 (history management unit 38) sets a correction table in association with the acquired machine state information. The data is stored in the storage unit 32 or the like (S109).

[Operation processing of history]
Next, operation processing of the history accumulated in the above procedure will be described with reference to FIG. The control unit 31 (history management unit 38) of the color image output device 30 confirms whether or not the history is accumulated when the color confirmation chart is output (S201). Whether or not history is accumulated is determined by whether or not the number of accumulated histories is equal to or greater than a certain number. If no history is accumulated, the history accumulation processing shown in FIG. 7 is performed (S207).

  When the history is accumulated, when the control unit 31 (correction control unit 39) receives an instruction to output the color confirmation chart (S202), the control unit 31 (correction control unit 39) sets the color value of the input color of each patch of the color confirmation chart. On the other hand, a color conversion table stored in advance is applied to convert it into an output device value (S203). Then, the control unit 31 (correction control unit 39) performs correction amount estimation processing (S204).

  FIG. 9 shows details of the correction amount estimation processing. First, it is determined from the accumulated history whether or not the correction amount corresponding to the input color is singular data (S301). If it is determined that the correction amount corresponding to the input color is singular data, the correction amount is not used for color correction and the input color is not corrected or an input color other than the input color (for example, the input color) The correction amount in the machine state of the current color image output device 30 is estimated from the correction amount of the input color close to the color (S302). For example, an average value of correction amounts of input colors other than the input color is estimated as a correction amount in the current machine state of the color image output device 30. On the other hand, if it is determined that the correction amount corresponding to the input color is not singular data, the current machine state of the color image output device 30 is determined from the correction amount of the input color (a part or all of the correction amount of the input color). The correction amount at is estimated (S303). For example, the average value of the correction amount of the input color is estimated as the correction amount in the machine state of the current color image output device 30. Then, it is determined whether the correction amount estimation has been completed for all the input colors (S304). If there is an input color for which the correction amount estimation has not been performed, the process returns to S301 and the same processing is repeated.

  Returning to FIG. 8, the control unit 31 (correction control unit 39) applies the estimated correction amount to convert the output device value into a corrected output device value (S205), and the print processing unit 36 calculates the corrected output device value. The color confirmation chart is output based on (S206).

  Note that the control unit 31 (history management unit 38) creates a correction table based on the correction value estimated above as necessary, and the created correction table corresponds to the current machine state of the color image output device 30. In addition, it is stored in the storage unit 22 or the like as history information. The control unit 31 (correction control unit 29), if necessary, if the number of correction amounts determined to be singular data exceeds a predetermined quantity or ratio, the control unit 31 (history management unit 38). The control unit 31 (history management unit 38) recreates the color conversion table in accordance with the instruction.

  Determination of whether or not the correction amount corresponding to the input color is singular data will be specifically described with reference to FIGS. For example, when the CMYK value of the input color A is (50, 50, 0, 0), it is assumed that the correction amount corresponding to the machine states 1 to 4 is the value in the center column as shown in FIG. When this correction amount is converted into a correction amount of a predetermined color space (for example, a color space of L * a * b * color system) so that the appearance of the color can be determined, the right column in FIG. 10 is obtained. The average value of the color space correction amount is (-1.25, 1.75, -2.5). This average value of the color space correction amount is called a tendency value. This tendency value exists for each input color. For example, the tendency values of the input colors (here, input colors A to D) are as shown in FIG. If the average value of the trend values of each input color is the overall trend value, and the overall trend value is (−1.4, 1.50, −2.3), the absolute value of the difference between the trend value for each input color and the overall trend value is shown in FIG. become that way. When the reference value (threshold value) for determining whether or not the data is singular data is (1, 1, 1), the correction amount of the input color C in which the absolute value of the difference is (1, 1, 1) or more is singular data. It is judged.

  FIG. 13 is a schematic diagram showing the relationship between the color space correction amount, the trend value, and the overall trend value, and is a diagram in which the correction amount is projected onto the a * b * plane in the color space of the L * a * b * color system. It is. The thin solid line in the figure shows the color space correction amount in each machine state for each input color, and the thick broken line in the figure shows the tendency value of each input color (the average value of the color space correction amount in each machine state). A thick solid line indicates an overall tendency value (an average value of tendency values of each input color). The trend values of the input colors at the upper left, upper right, and lower right of the figure are in the same direction as the overall trend values. However, the input color at the lower left of the figure (the input color surrounded by a circle) is the overall trend value. It faces in a different direction, and this input color corresponds to the input color C in FIG. If the output device value is corrected using the correction amount in which the absolute value of the difference between the trend value and the overall trend value exceeds the reference value, the color accuracy deteriorates. A correction amount corresponding to the current machine state of the color image output device 30 is estimated using a correction amount of an input color other than the input color (for example, an input color close to the input color) (for example, a * b * The correction amount of the color located on both sides of this input color on the plane is averaged and estimated).

  In this way, when outputting a color image, it is determined whether the correction amount of the correction table is singular data for each input color. If the correction amount is not singular data, the color image output device is used using the correction amount. A color image output device that estimates a correction amount in the current machine state of 30 and uses the correction amount of an input color other than the input color without using the correction amount when the correction amount of the input color is singular data. By estimating the correction amount in the current machine state of 30 and correcting the output device value corresponding to the input device value of the color image using the estimated correction amount, the history information is output in an output state different from the history storage time. Even when color correction is performed by using the color accuracy, deterioration of color accuracy can be avoided.

  In addition, this invention is not limited to description of the said Example, The structure and control can be suitably changed unless it deviates from the meaning of this invention.

  For example, in the above embodiment, the case where the color image output apparatus 30 performs the history accumulation process and the history operation process has been described. However, in the printing system of FIG. 1, the controller 20 performs the history accumulation process and the history operation process. The color correction control of the present invention can be similarly applied to the case where it is performed.

  In the above embodiment, when the correction amount of the input color is singular data, the correction amount is estimated using the correction amount of the input color other than the input color. However, for the input color, the color correction using the correction amount is performed. (The output device value converted by the color conversion table is used as it is).

  In the above embodiment, the correction amount is converted into the correction amount of the color space of the L * a * b * color system when determining whether the correction amount of the input color is singular data. The color correction control of the present invention can be similarly applied to the case of converting the color value into a correction amount in an arbitrary color space that can be converted.

  The present invention relates to a color correction apparatus that performs color correction using a correction table, a color correction method in a printing system including the color correction apparatus, a color correction program that operates in the color correction apparatus, and a recording medium that records the color correction program Is available.

10 Client terminal 11 Control unit 11a CPU
11b ROM
11c RAM
12 storage unit 13 network I / F unit 14 display unit 15 operation unit 16 OS
17 Document creation application 18 Printer driver 20 Controller 21 Controller 21a CPU
21b ROM
21c RAM
DESCRIPTION OF SYMBOLS 22 Memory | storage part 23 Image processing part 24 RIP part 25 Network I / F part 26 Printer I / F part 27 Information acquisition part 28 History management part 29 Correction control part 30 Color image output apparatus 31 Control part 31a CPU
31b ROM
31c RAM
32 Storage Unit 33 Controller I / F Unit 34 Panel Operation Unit 35 Image Reading Unit 36 Print Processing Unit 37 Information Acquisition Unit 38 History Management Unit 39 Correction Control Unit 40 Colorimeter 50 Communication Network

Claims (22)

A color correction device that corrects an output device value of a color image output device converted from an input device value using a color conversion table according to a machine state of the color image output device,
An information acquisition unit for acquiring machine state information for specifying a machine state of the color image output device;
Based on the color values obtained by measuring the color chart output from the color image output device with a colorimeter, the correction amount of the output device value corresponding to the input device value of the color chart is determined, and the correction is performed for each input color. A history management unit that creates a correction table describing the amount, stores the correction table in the storage unit as history information in association with the machine state information;
When instructing the color image output device to output a color image, the correction amount in the current machine state of the color image output device is estimated for each input color with reference to the stored correction table, and the estimated input A correction control unit that corrects an output device value corresponding to an input device value of the color image using the correction amount for each color, and
The correction control unit determines whether the correction amount is singular data for each input color when estimating the correction amount, and the correction amount determined to be the singular data is used for correcting the output device value. do not do,
A color correction apparatus characterized by the above. The correction control unit estimates the correction amount of the predetermined input color using the correction amount of the input color other than the predetermined input color when the correction amount of the predetermined input color is determined to be the singular data. To
The color correction apparatus according to claim 1. The correction control unit compares, for each input color, a trend value that represents the tendency of the correction amount of each input color and an overall trend value that represents the tendency of the correction amount of all input colors, Determining whether the correction amount is the singular data for each input color;
The color correction apparatus according to claim 1, wherein: The correction control unit converts the correction amount into a correction amount of a predetermined color space, sets an average value of the correction amount of the predetermined color space of each input color as the tendency value of the input color, and all An average value of the trend values of the input colors is set as the overall trend value, and based on whether an absolute value of a difference between the trend value and the overall trend value of each input color exceeds a predetermined threshold value And determining whether the correction amount is the singular data,
The color correction apparatus according to claim 3. The history management unit creates a correction table using the estimated correction amount, and stores the created correction table in the storage unit as the history information in association with current machine state information of the color image output device To
The color correction apparatus according to claim 1, wherein the color correction apparatus is a color correction apparatus. The correction control unit instructs the history management unit to recreate the color conversion table when the number of correction amounts determined to be the singular data exceeds a predetermined number or ratio.
The color correction apparatus according to claim 1, wherein the color correction apparatus is a color correction apparatus. The machine state includes any one of a usage time of each member constituting a print engine of the color image output apparatus, an environmental humidity of the print engine, and an environmental temperature of the print engine,
The information acquisition unit acquires the machine state information from a measurement unit provided in the print engine;
The color correction apparatus according to claim 1, wherein the color correction apparatus is a color correction apparatus. The color correction device is built in the color image output device,
The color correction apparatus according to claim 1, wherein the color correction apparatus is a color correction apparatus. A color correction device that corrects an output device value of a color image output device converted from an input device value using a color conversion table according to a machine state of the color image output device, the color image output device, and colorimetry A color correction method in a printing system comprising:
The color correction device includes:
A first process for obtaining machine state information for specifying a machine state of the color image output device from the color image output device;
A second process for obtaining a color value obtained by measuring the color chart output from the color image output device from the colorimeter;
A third process for determining a correction amount of an output device value corresponding to the input device value of the color chart based on the acquired color value, and creating a correction table describing the correction amount for each input color;
A fourth process of storing the correction table in the storage unit as history information in association with the machine state information;
When instructing the color image output device to output a color image, the correction amount in the current machine state of the color image output device is estimated for each input color with reference to the stored correction table, and the estimated input Performing a fifth process of correcting an output device value corresponding to an input device value of the color image using the correction amount for each color;
In the fifth process, when the correction amount is estimated, it is determined whether the correction amount is singular data for each input color, and the correction amount determined to be the singular data is used for correcting the output device value. do not do,
A color correction method characterized by the above. In the fifth process, when the correction amount of the predetermined input color is determined to be the singular data, the correction amount of the predetermined input color is estimated using the correction amount of the input color other than the predetermined input color. To
The color correction method according to claim 9. In the fifth process, for each input color, by comparing the tendency value indicating the tendency of the correction amount of each input color and the overall tendency value indicating the tendency of the correction amount of all input colors, Determining whether the correction amount is the singular data for each input color;
The color correction method according to claim 9 or 10, wherein: In the fifth process, the correction amount is converted into a correction amount of a predetermined color space, an average value of the correction amounts of the predetermined color space of each input color is set as the tendency value of the input color, and all An average value of the trend values of the input colors is set as the overall trend value, and based on whether an absolute value of a difference between the trend value and the overall trend value of each input color exceeds a predetermined threshold value And determining whether the correction amount is the singular data,
The color correction method according to claim 11. In the fifth process, a correction table is created using the estimated correction amount, and the created correction table is stored as the history information in the storage unit in association with the current machine state information of the color image output device. To
The color correction method according to claim 9, wherein the color correction method is performed. In the fifth process, when the number of correction amounts determined to be the singular data exceeds a predetermined number or ratio, the re-creation of the color conversion table is instructed.
The color correction method according to claim 9, wherein the color correction method is a color correction method. The machine state includes any one of a usage time of each member constituting a print engine of the color image output apparatus, an environmental humidity of the print engine, and an environmental temperature of the print engine,
In the first process, the machine state information is acquired from a measurement unit provided in the print engine.
The color correction method according to claim 9, wherein the color correction method is a color correction method. A color correction program that operates in a color correction device that corrects an output device value of a color image output device converted from an input device value using a color conversion table according to a machine state of the color image output device,
In the color correction device,
A first process for acquiring machine state information for specifying a machine state of the color image output device from the color image output device;
A second process for obtaining a color value obtained by measuring the color chart output from the color image output device from a colorimeter;
A third process for determining a correction amount of an output device value corresponding to the input device value of the color chart based on the acquired color value, and creating a correction table describing the correction amount for each input color;
A fourth process for storing the correction table in the storage unit as history information in association with the machine state information;
When instructing the color image output device to output a color image, the correction amount in the current machine state of the color image output device is estimated for each input color with reference to the stored correction table, and the estimated input Performing a fifth process of correcting an output device value corresponding to an input device value of the color image using the correction amount for each color;
In the fifth process, when the correction amount is estimated, it is determined whether the correction amount is singular data for each input color, and the correction amount determined to be the singular data is used for correcting the output device value. do not do,
A color correction program characterized by that. In the fifth process, when the correction amount of the predetermined input color is determined to be the singular data, the correction amount of the predetermined input color is estimated using the correction amount of the input color other than the predetermined input color. To
The color correction program according to claim 16. In the fifth process, for each input color, by comparing the tendency value indicating the tendency of the correction amount of each input color and the overall tendency value indicating the tendency of the correction amount of all input colors, Determining whether the correction amount is the singular data for each input color;
The color correction program according to claim 16 or 17, characterized by the above. In the fifth process, the correction amount is converted into a correction amount of a predetermined color space, an average value of the correction amounts of the predetermined color space of each input color is set as the tendency value of the input color, and all An average value of the trend values of the input colors is set as the overall trend value, and based on whether an absolute value of a difference between the trend value and the overall trend value of each input color exceeds a predetermined threshold value And determining whether the correction amount is the singular data,
The color correction program according to claim 18. In the fifth process, a correction table is created using the estimated correction amount, and the created correction table is stored as the history information in the storage unit in association with the current machine state information of the color image output device. To
The color correction program according to any one of claims 16 to 19, wherein In the fifth process, when the number of correction amounts determined to be the singular data exceeds a predetermined number or ratio, the re-creation of the color conversion table is instructed.
21. The color correction program according to claim 16, wherein the color correction program is any one of claims 16 to 20. The machine state includes any one of a usage time of each member constituting a print engine of the color image output apparatus, an environmental humidity of the print engine, and an environmental temperature of the print engine,
In the first process, the machine state information is acquired from a measurement unit provided in the print engine.
The color correction program according to any one of claims 16 to 21, wherein the color correction program is described above.

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