Color conversion parameter creation device, image forming system, color conversion parameter creation method, and program

Abstract

To reduce the workload on a user in creation of a color conversion parameter.SOLUTION: A control unit of an image forming apparatus (color conversion parameter creation device) extracts two or more objects included in image data to be processed (step S1). The control unit (selection means) selects two or more color conversion parameters corresponding to the extracted two or more objects, from a plurality of color conversion parameters stored in a storage unit (storage means) of a cloud server (step S2). The control unit (creation means) merges the selected two or more color conversion parameters to create a new color conversion parameter (step S3).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a color conversion parameter creating device, an image forming system, a color conversion parameter creating method, and a program. [Background technology]

[0002] Conventionally, color management software has been used to create profiles (ICC profiles) that comply with the ICC (International Color Consortium). This software has the function of creating ICC profiles that describe the characteristics of devices such as monitors, scanners, and printers (image forming devices). Users can also use this software to re-edit (tune) ICC profiles.

[0003] Patent Document 1 discloses an image forming device that separates print data into types of components (objects), classifies each of the separated components, and performs color conversion processing on each of the classified components according to the characteristics of the component. This image forming device combines the components that have undergone color conversion processing, and forms an image based on the combined print data.

[0004] In image formation, it is desirable to perform color conversion (color adjustment) appropriate for the object (object) contained in the target image. For example, for an image containing apples, color conversion is performed using a CMM (Color Management Module) for apples, and for an image containing melons, color conversion is performed using a CMM for melons. A CMM is a module that performs color conversion by referencing a color conversion profile. If only one type of object exists in an image, it is sufficient to select a CMM appropriate for that object. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-81065 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when an image contains multiple objects (for example, an apple and a melon), using a CMM suitable for one of the objects in the image does not result in suitable color conversion for another object. While it would be possible to prepare CMMs suitable for multiple objects, the number of possible object combinations is enormous. Therefore, it is difficult to prepare CMMs (color conversion parameters) for all combinations. Therefore, users must create color conversion parameters as needed. Creating color conversion parameters requires time and effort, as well as the user's knowledge and experience.

[0007] The present invention has been made in consideration of the above-mentioned problems in the prior art, and an object of the present invention is to reduce the workload on the user in creating color conversion parameters. [Means for solving the problem]

[0008] In order to solve the above problem, the invention described in claim 1 is a color conversion parameter creation device that includes a selection means that selects two or more color conversion parameters from a plurality of color conversion parameters stored in a storage means, and a creation means that merges the two or more selected color conversion parameters to create a new color conversion parameter.

[0009] According to a second aspect of the present invention, the color conversion parameter creating device of the first aspect further comprises a color conversion unit that uses the new color conversion parameters to perform color conversion on image data to be processed.

[0010] The invention described in claim 3 is a color conversion parameter creation device described in claim 2, which is provided with a correction means for correcting the new color conversion parameters when the color conversion results using the new color conversion parameters are inappropriate.

[0011] The invention described in claim 4 is a color conversion parameter creation device described in claim 3, wherein the modification means narrows the data spacing in color areas in the color space where the color conversion result is inappropriate for the new color conversion parameters.

[0012] The invention described in claim 5 is a color conversion parameter creation device described in claim 1, wherein the selection means extracts two or more objects contained in the image data to be processed and selects two or more color conversion parameters corresponding to each of the extracted two or more objects.

[0013] A sixth aspect of the present invention provides the color conversion parameter creating device of the first aspect, wherein the selection means selects the two or more color conversion parameters for each page of image data to be processed.

[0014] The invention described in claim 7 is a color conversion parameter creation device described in claim 1, wherein the selection means selects a first color conversion parameter corresponding to a first object and a second color conversion parameter corresponding to a second object, and the creation means does not merge the first color conversion parameter and the second color conversion parameter when the distance between the color region corresponding to the first object and the color region corresponding to the second object in the color space is less than a first threshold value.

[0015] The invention described in claim 8 is the color conversion parameter creation device described in claim 7, wherein the creation means averages the first color conversion parameter and the second color conversion parameter for the color region corresponding to the first object and the color region corresponding to the second object in the color space when the distance is greater than or equal to the first threshold and less than or equal to the second threshold.

[0016] The invention described in claim 9 is an image forming system comprising a storage means for storing a plurality of color conversion parameters, a selection means for selecting two or more color conversion parameters from the plurality of color conversion parameters stored in the storage means, a creation means for merging the two or more selected color conversion parameters to create new color conversion parameters, a color conversion means for color converting image data to be processed using the new color conversion parameters, and an image forming means for forming an image based on the color-converted image data.

[0017] The invention described in claim 10 is a color conversion parameter creation method including a selection step of selecting two or more color conversion parameters from a plurality of color conversion parameters stored in a storage means, and a creation step of merging the selected two or more color conversion parameters to create a new color conversion parameter.

[0018] The invention described in claim 11 is a program for causing a computer to function as a selection means for selecting two or more color conversion parameters from a plurality of color conversion parameters stored in a storage means, and a creation means for merging the two or more selected color conversion parameters to create new color conversion parameters. [Effects of the Invention]

[0019] According to the present invention, the workload of the user in creating color conversion parameters can be reduced. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a system configuration diagram of an image forming system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the functional configuration of a cloud server. [Figure 3] FIG. 2 is a block diagram showing a functional configuration of the image forming apparatus. [Figure 4]FIG. 10 is a diagram illustrating an example in which user A creates a CMM suitable for apples and a CMM suitable for melons. [Figure 5] 10 is a flowchart showing a first merge process executed in the image forming apparatus. [Figure 6] This is a diagram showing an example in which user B creates a new CMM from two existing CMMs. [Figure 7] FIG. 10 is a diagram illustrating an example of switching CMMs on a page-by-page basis. [Figure 8] 10 is a flowchart showing a second merge process executed in the image forming apparatus according to the second embodiment. [Figure 9] FIG. 10 is a diagram for explaining a method for creating a new CMM. [Figure 10] 10 is an example of an image in which a pseudo contour occurs. [Figure 11] FIG. 10 is a diagram for explaining a method for correcting a CMM. [Figure 12] 1 is an example of an image formed using a modified CMM. [Figure 13] 11 is a flowchart showing a new CMM creation process executed in an image forming apparatus according to a third embodiment. [Figure 14] FIG. 10 is a diagram for explaining a method for creating a new CMM by averaging. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Advantages and features provided by the embodiments will be understood from the following detailed description and drawings. However, the scope of the present invention is not limited to the embodiments disclosed below or the examples shown in the drawings.

[0022] [First embodiment] First, a first embodiment of the present invention will be described. FIG. 1 is a system configuration diagram of an image forming system 100 in the first embodiment. The image forming system 100 includes a cloud server 10 and image forming apparatuses 20A, 20B, 20C, etc., which serve as color conversion parameter creation devices. The cloud server 10 and the image forming apparatuses 20A, 20B, 20C, etc., are connected to each other so as to be able to communicate data via a communication network N such as the Internet. Hereinafter, when there is no need to distinguish between the image forming apparatuses 20A, 20B, 20C, etc., they will be referred to as "image forming apparatuses 20."

[0023] The cloud server 10 manages a CMM (Color Management Module) as color conversion parameters created in each image forming device 20. The CMM is a module that converts color data into color data in another color space by referencing a color conversion profile (color conversion table, color conversion parameters) that describes the characteristics of the target device.

[0024] The image forming apparatus 20 is a multi-functional peripheral (MFP) that has multiple functions such as a scanner function, a copy function, a printer function, and a facsimile function.

[0025] 2 is a block diagram showing the functional configuration of cloud server 10. Cloud server 10 includes a control unit 11, a ROM (Read Only Memory) 12, a memory 13, a communication unit 14, a storage unit 15, and the like.

[0026] The control unit 11 includes a CPU (Central Processing Unit). The control unit 11 reads out system programs and various processing programs stored in the ROM 12, and loads the read programs into the memory 13. The control unit 11 centrally controls the operation of each part of the cloud server 10 in accordance with the loaded programs.

[0027] The ROM 12 stores various programs executed by the control unit 11 as well as various data. The memory 13 is a random access memory (RAM) that temporarily stores data required when the control unit 11 executes various programs.

[0028] The communication unit 14 includes various interfaces for connecting to the communication network N. The communication unit 14 transmits and receives data to and from the image forming apparatus 20 via the communication network N.

[0029] The storage unit 15 (storage means) is configured with an HDD (Hard Disk Drive), an SSD (Solid State Drive), a non-volatile semiconductor memory, etc. The storage unit 15 stores various data related to the operation of the cloud server 10. The storage unit 15 stores a management table 151 and multiple CMMs.

[0030] Each CMM is created in one of the image forming devices 20. Alternatively, each CMM may be prepared in advance in the cloud server 10. Each CMM includes data of a color conversion table (color conversion parameters). The color conversion table is a lookup table that indicates the correspondence between coordinate values ​​in an input color space and coordinate values ​​in an output color space for multiple grid points.

[0031] Here, a color conversion table showing the correspondence between XYZ values ​​and CMYK values ​​is used as the printer profile for the image forming unit 25 (see FIG. 3) of the image forming apparatus 20. The color conversion table defines a combination of (C,M,Y,K) values ​​for each grid point (X,Y,Z). The CMM refers to the color conversion table and calculates the CMYK values ​​by interpolation based on the (C,M,Y,K) values ​​corresponding to the surrounding grid points (X,Y,Z) for the input XYZ values.

[0032] The management table 151 is a table for managing a plurality of CMMs stored in the storage unit 15. In the management table 151, for each CMM, identification information of the CMM, a target object, and a target color region are associated with each other. The CMM identification information is information for identifying the CMM. The target object is information that indicates an object that is suitable for color conversion performed by the CMM. The target color region is information that indicates the color region that corresponds to the target object in the color space. For example, the target color region indicates which color region (range of XYZ values) the target object corresponds to in the XYZ color space.

[0033] 3 is a block diagram showing the functional configuration of the image forming apparatus 20. The image forming apparatus 20 includes a control unit 21, an operation unit 22, a display unit 23, an image reading unit 24, an image forming unit 25, a ROM 26, a memory 27, a communication unit 28, a storage unit 29, etc.

[0034] The control unit 21 includes a CPU. The control unit 21 reads out the system program and various processing programs stored in the ROM 26 and loads the read out programs into the memory 27. The control unit 21 performs centralized control of the operations of each unit of the image forming apparatus 20 in accordance with the loaded programs. The control unit 21 controls the entire image forming apparatus 20 for various jobs such as a scan job, a copy job, and a print job.

[0035] The operation unit 22 has various operation keys and a touch screen, and outputs operation signals based on user operations to the control unit 21. The various operation keys accept various instruction operations and input operations such as numbers from the user. The touch screen is formed to cover the display screen of the display unit 23. The touch screen accepts touch operations on the display screen and detects the touch position.

[0036] The display unit 23 is configured by an LCD (Liquid Crystal Display). The display unit 23 displays various screens in accordance with instructions of a display signal input from the control unit 21.

[0037] The image reading unit 24 optically reads an original document and generates image data. For example, the image reading unit 24 generates image data of red (R), green (G), and blue (B). The image reading unit 24 outputs the image data to the control unit 21.

[0038] Image forming unit 25 (image forming means) forms an image on paper based on image data of cyan (C), magenta (M), yellow (Y), and black (K). In particular, when image forming device 20 operates as a printer, image forming unit 25 forms an image on paper based on image data received via communication unit 28. When image forming device 20 operates as a copier, image forming unit 25 forms an image on paper based on image data generated by image reading unit 24.

[0039] The ROM 26 stores various programs executed by the control unit 21 as well as various data. The memory 27 is a RAM, and temporarily stores data required when the control unit 21 executes various programs.

[0040] The communication unit 28 includes various interfaces for connecting to the communication network N. The communication unit 28 transmits and receives data to and from the cloud server 10 via the communication network N. The storage unit 29 is configured by an HDD, an SSD, a non-volatile semiconductor memory, etc. The storage unit 29 stores various data related to the operation of the image forming apparatus 20, etc.

[0041] The control unit 21 (selection means) selects two or more color conversion parameters from among a plurality of color conversion parameters stored in the storage unit 15 of the cloud server 10.

[0042] The control unit 21 extracts two or more objects included in the image data to be processed, and selects two or more color conversion parameters corresponding to each of the two or more extracted objects.

[0043] The control unit 21 (creation means) merges the two or more selected color conversion parameters to create a new color conversion parameter.

[0044] The control unit 21 (color conversion means) color-converts the image data to be processed using the new color conversion parameter. The control unit 21 controls the image forming unit 25 to form an image on the paper based on the color-converted image data.

[0045] Next, the operation in the image forming system 100 of the first embodiment will be described. <CMM Creation Process> First, the creation of a CMM for a single object will be described. The CMM includes, for example, a color conversion table (color conversion parameter) for color-converting a color value (XYZ value) in the XYZ color space to a device value (CMYK value).

[0046] FIG. 4 shows an image when user A creates a CMM1 suitable for the first object (apple) and a CMM2 suitable for the second object (melon) in the image forming apparatus 20A. Known methods can be applied for the creation and adjustment of the CMM.

[0047] The control unit 21 of the image forming apparatus 20A creates a CMM1 suitable for the first object (apple) according to an operation from the operation unit 22 by user A. CMM1 has a color conversion parameter (color conversion table) specialized for color conversion of a color region 31 corresponding to an apple (for example, around red). This color conversion parameter is optimally adjusted by user A in the color conversion of the color region 31 corresponding to the apple. The control unit 21 color-converts the image data including the apple using CMM1. The control unit 21 controls the image forming unit 25 to form an image of the apple on the paper based on the color-converted image data.

[0048] Control unit 21 of image forming apparatus 20A creates a CMM2 suitable for a second object (melon) in accordance with operations performed by user A on operation unit 22. CMM2 has color conversion parameters (color conversion table) specialized for color conversion of a color region 32 corresponding to a melon (for example, around yellow-green). These color conversion parameters are adjusted by user A to be optimal for color conversion of color region 32 corresponding to a melon. Control unit 21 uses CMM2 to color convert image data including a melon. Control unit 21 controls image forming unit 25 to form an image of a melon on paper based on the color-converted image data.

[0049] The control unit 21 of the image forming apparatus 20A registers the created CMM1 and CMM2 in the cloud server 10. Specifically, the control unit 21 transmits the CMM1 and CMM2 to the cloud server 10 via the communication unit 28 in accordance with an operation by user A on the operation unit 22. The control unit 21 also transmits the target object and target color region of each CMM to the cloud server 10 via the communication unit 28. In the cloud server 10, the control unit 11 stores the CMM1 and CMM2 in the memory unit 15 and stores information about the CMM1 and CMM2 in the management table 151. Specifically, the control unit 11 assigns identification information to the CMM to be registered. The control unit 11 associates the CMM identification information, the target object (apple, melon, etc.), and the target color region (the color region corresponding to the apple, melon, etc.) and stores them in the management table 151.

[0050] In this example, it is assumed that user A creates CMM1 and CMM2, but CMM1 and CMM2 may be created by different users. Also, CMM1 and CMM2 may be created in different image forming apparatuses 20.

[0051] <First merge process> 5 is a flowchart showing the first merging process executed in image forming apparatus 20. The first merging process is realized by software processing in cooperation between control unit 21 and a program stored in ROM 26. The first merging process is executed in a situation where a user wants to simultaneously form an image containing two or more objects on a single sheet of paper, but cloud server 10 does not have a CMM suitable for such an image.

[0052] First, the control unit 21 extracts two or more objects from the image data to be processed (step S1). For example, the control unit 21 analyzes the image data to be processed and extracts the objects included in the image data based on color, shape, etc.

[0053] Next, the control unit 21 selects two or more CMMs corresponding to the two or more extracted objects, respectively (step S2). FIG. 6 illustrates an example in which user B creates a new CMM on image forming apparatus 20B. For example, when an apple and a melon are extracted from image data to be processed, control unit 21 of image forming apparatus 20B acquires CMM1 appropriate for the first object (apple) and CMM2 appropriate for the second object (melon) from cloud server 10. Specifically, control unit 21 transmits a request to acquire CMM1 corresponding to apple and a request to acquire CMM2 corresponding to melon to cloud server 10 via communication unit 28. Control unit 11 of cloud server 10 refers to management table 151, reads CMM1 corresponding to apple and CMM2 corresponding to melon from storage unit 15, and provides the read CMM1 and CMM2 to image forming apparatus 20B. Control unit 21 of image forming apparatus 20B acquires CMM1 corresponding to apple and CMM2 corresponding to melon from cloud server 10 via communication unit 28.

[0054] Next, the control unit 21 merges the two or more selected CMMs to create a new CMM (step S3). 6, the control unit 21 creates a CMM41 by merging the grid point data (CMYK values ​​corresponding to grid point XYZ values) of the color region 32 corresponding to the second object (melon) in the color conversion table of CMM2 with the color conversion table of CMM1 as a base. In other words, the control unit 21 replaces only the portion of the color region 32 in the color conversion table of CMM1 with the data of the color conversion table of CMM2. Note that in the new CMM41, the grid point data originally included in the color conversion table of CMM1 is retained for the color region 31 corresponding to the first object (apple).

[0055] In addition, when merging three or more color conversion parameters, the control unit 21 uses the color conversion table of a certain CMM as a base and merges the grid point data of the color area corresponding to the object in the color conversion table of that CMM for each of the other CMMs.

[0056] Next, the control unit 21 uses the new CMM to perform color conversion on the image data to be processed (step S4). In the example shown in FIG. 6, the control unit 21 uses a CMM 41 suitable for the first object (apple) and the second object (melon) to convert the XYZ values ​​of the image data to be processed into CMYK values.

[0057] Next, the control unit 21 controls the image forming unit 25 to form an image on a sheet based on the image data (CMYK values) after color conversion (step S5). In the example shown in FIG. 6, the control unit 21 controls the image forming unit 25 to simultaneously form an image including a first object (apple) and a second object (melon) on one sheet of paper.

[0058] Next, the control unit 21 registers the new CMM in the cloud server 10 (step S6). Specifically, the control unit 21 transmits the new CMM to the cloud server 10 via the communication unit 28 in accordance with a user's operation on the operation unit 22. The control unit 21 also transmits the target object and target color region of the new CMM to the cloud server 10 via the communication unit 28. In the cloud server 10, the control unit 11 stores the new CMM in the memory unit 15 and stores information about the new CMM in the management table 151. For example, the control unit 11 assigns identification information to the new CMM. The control unit 11 associates the identification information of the new CMM with the target objects (apple and melon), and the target color regions (the color region corresponding to the apple and the color region corresponding to the melon), and stores them in the management table 151.

[0059] As described above, according to the first embodiment, the control unit 21 of the image forming apparatus 20 selects two or more color conversion parameters from among the multiple color conversion parameters stored in the storage unit 15 of the cloud server 10. The control unit 21 merges the two or more selected color conversion parameters to create a new color conversion parameter. In this way, the control unit 21 can create a new color conversion parameter using two or more color conversion parameters that have already been created. Therefore, the control unit 21 can reduce the user's workload in creating color conversion parameters.

[0060] The control unit 21 uses the new color conversion parameters to perform color conversion on the image data to be processed, thereby enabling the control unit 21 to use the new color conversion parameters created from two or more color conversion parameters for color conversion.

[0061] The control unit 21 extracts two or more objects included in the image data to be processed and selects two or more color conversion parameters corresponding to each of the two or more extracted objects, thereby enabling the control unit 21 to select two or more color conversion parameters suitable for creating new color conversion parameters.

[0062] The control unit 21 of the image forming apparatus 20 may select two or more color conversion parameters for each page of the image data to be processed. In this case, the control unit 21 may create and use new color conversion parameters for each page. After creating new color conversion parameters from two or more color conversion parameters, the control unit 21 may reuse the new color conversion parameters.

[0063] FIG. 7 shows an example of switching CMMs on a page-by-page basis. For each page of image data to be processed, the control unit 21 extracts objects included in the image. The control unit 21 selects a CMM corresponding to the extracted object. For example, the image data of the first page contains apples and melons, so the control unit 21 selects CMM1 suitable for apples and CMM2 suitable for melons, and creates CMM41 suitable for apples and melons (see FIG. 6). The control unit 21 performs color conversion on the image data of the first page using CMM41. The image data of the second page contains only melons, so the control unit 21 selects CMM2 suitable for color conversion of melons. The image data of the third page contains only apples, so the control unit 21 selects CMM1 suitable for color conversion of apples. The image data of the i-th page contains apples and melons, so the control unit 21 selects CMM41 suitable for color conversion of apples and melons.

[0064] [Second embodiment] Next, a second embodiment to which the present invention is applied will be described. The image forming system of the second embodiment has a configuration similar to that of the image forming system 100 shown in the first embodiment. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and illustrations and descriptions thereof will be omitted. The configuration and processing characteristic of the second embodiment will be described below.

[0065] If the color conversion result using the new color conversion parameters is not appropriate, the control unit 21 (correction means) of the image forming apparatus 20 corrects the new color conversion parameters. The control unit 21 corrects the new color conversion parameters by narrowing the data intervals in color regions in the color space where the color conversion results are inappropriate for the new color conversion parameters. The control unit 21 then refines the grid points in the corresponding color region of the color conversion table. To narrow the data intervals for the new color conversion parameters, the cloud server 10 must hold more detailed data for the selected color conversion parameters in advance. However, it is sufficient to hold more detailed data around the color region corresponding to the object corresponding to the color conversion parameters.

[0066] Next, the operation of the image forming system 100 of the second embodiment will be described. The CMM creation process executed in the image forming apparatus 20 is the same as that in the first embodiment.

[0067] 8 is a flowchart showing the second merging process executed in the image forming apparatus 20. The second merging process is realized by software processing in cooperation between the control unit 21 and a program stored in the ROM 26. The processing in steps S11 to S15 is the same as the processing in steps S1 to S5 of the first merge processing (see FIG. 5), and therefore a description thereof will be omitted.

[0068] FIG. 9 shows an example of a method for creating a new CMM in step S13. CMM1 has optimal grid point data (correspondence between data before and after color conversion) for color gamut 33, which corresponds to the first object in the XYZ color space. CMM2 has optimal grid point data for color gamut 34, which corresponds to the second object in the XYZ color space. Control unit 21 merges the grid point data for color gamut 34 from the color conversion table of CMM2 into the color conversion table of CMM1 to create a new CMM.

[0069] After step S15, the user visually checks the image formed on the paper. The user determines whether the color conversion result (output result) is appropriate. The user also determines whether any defects are within an acceptable range. When color conversion is performed using the new CMM and an image is formed on the paper, the gradation changes of certain colors may no longer be smooth, and false contours may appear on the image. Figure 10 shows an example of an image in which false contours have appeared.

[0070] Next, the control unit 21 receives a determination as to whether or not the color conversion result is appropriate, based on an operation by the user from the operation unit 22 (step S16). For example, the control unit 21 causes the display unit 23 to display a confirmation screen for determining whether or not the color conversion result is appropriate. The user operates the operation unit 22 to select whether or not the color conversion result is appropriate on the confirmation screen. If the color conversion result is appropriate (step S16; YES), the control unit 21 registers a new CMM in the cloud server 10 (step S17). Details of the method for registering the CMM are the same as those in step S6 of the first merge process (see FIG. 5).

[0071] In step S16, if the color conversion result is not appropriate (step S16; NO), control unit 21 accepts designation of a defective part on the image by a user's operation from operation unit 22 (step S18). For example, control unit 21 causes display unit 23 to display an image based on the color-converted image data used for image formation. Then, the user designates a defective part on the image displayed on display unit 23 via operation unit 22. The control unit 21 may display an image based on image data obtained by reading the paper after image formation using the image reading unit 24 on the display unit 23, and may accept designation of a defective portion on the image.

[0072] Next, the control unit 21 acquires segmented data corresponding to the color region of the defective part (step S19). Specifically, the control unit 21 acquires, in the new CMM, grid point data with narrower intervals for the color region of the defective part from the existing CMM that is the source of the data corresponding to the color region of the defective part.

[0073] Next, the control unit 21 modifies the new CMM (step S20). The control unit 21 replaces the grid point data corresponding to the color region of the defective part in the color conversion table of the new CMM with the acquired segmentation data. FIG. 11 shows an example of a new CMM 42 created by the creation method shown in FIG. 9. Assume that a defect occurs in the color region 34 of the new CMM 42 that was merged from CMM2. In this case, the control unit 21 acquires the segmentation data (grid point data) corresponding to the color region 34 from CMM2 and replaces the color region 34 of CMM 42 with the acquired segmentation data. In other words, the control unit 21 creates a color conversion table with a narrower grid point spacing for the color region 34.

[0074] After step S20, the process returns to step S14. In step S14, the control unit 21 uses the corrected CMM to color convert the image data to be processed. FIG. 12 is an example of an image formed using the corrected CMM. In the image shown in FIG. 12, the occurrence of false contours is suppressed.

[0075] The control unit 21 repeats the process until the answer is "YES" in step S16. An upper limit may be set for the number of repetitions. In this case, the control unit 21 suspends the process after the upper limit is reached. The control unit 21 also suspends the process if there is no further segmentation data for two or more CMMs selected in step S12, since the CMMs cannot be modified.

[0076] As described above, according to the second embodiment, similar to the first embodiment, the control unit 21 of the image forming apparatus 20 can reduce the workload of the user in creating color conversion parameters. If the color conversion results using the new color conversion parameters are not appropriate, the control unit 21 corrects the new color conversion parameters. By correcting the color conversion parameters, the control unit 21 can create more appropriate color conversion parameters.

[0077] Specifically, the control unit 21 narrows the data intervals in color regions in the color space where the color conversion results are inappropriate for the new color conversion parameters, thereby enabling the control unit 21 to increase the accuracy of the post-color conversion values ​​calculated using the color conversion parameters.

[0078] In the second embodiment, a case has been described in which a user visually checks whether the color conversion result is appropriate. Alternatively, a scanner may be provided on the transport path of paper on which an image has been formed in the image forming apparatus 20. In this case, the control unit 21 analyzes image data obtained by reading an image with the scanner and determines whether the color conversion result is appropriate. Alternatively, the control unit 21 may analyze image data obtained by reading an image with the image reading unit 24 and determine whether the color conversion result is appropriate.

[0079] [Third embodiment] Next, a third embodiment to which the present invention is applied will be described. The image forming system of the third embodiment has a configuration similar to that of the image forming system 100 shown in the first embodiment. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and illustrations and descriptions thereof will be omitted. The configuration and processing characteristic of the third embodiment will be described below.

[0080] In the first and second embodiments, when selecting two or more color conversion parameters, the selection of three or more color conversion parameters is also included. In the third embodiment, it is assumed that a new color conversion parameter is created from two color conversion parameters.

[0081] The control unit 21 (selection means) of the image forming device 20 selects a first color conversion parameter corresponding to the first object and a second color conversion parameter corresponding to the second object from among multiple color conversion parameters stored in the memory unit 15 of the cloud server 10.

[0082] When the distance between the color region corresponding to the first object and the color region corresponding to the second object in the color space is less than a first threshold, the control unit 21 (creation means) does not merge the first color conversion parameters with the second color conversion parameters. That is, the control unit 21 adopts the first color conversion parameters or the second color conversion parameters as they are and uses them as new color conversion parameters. When the distance between the color region corresponding to the first object and the color region corresponding to the second object is short, there is not much difference between using the first color conversion parameters or the second color conversion parameters.

[0083] When the distance between the color area corresponding to the first object and the color area corresponding to the second object in the color space is greater than or equal to a first threshold and less than or equal to a second threshold, the control unit 21 (creation means) averages the first color conversion parameter and the second color conversion parameter for the color area corresponding to the first object and the color area corresponding to the second object in the color space.

[0084] When the distance between the color area corresponding to the first object and the color area corresponding to the second object in the color space is greater than a second threshold, the control unit 21 (creation means) merges the first object and the second object and creates new color conversion parameters.

[0085] Next, the operation of the image forming system 100 of the third embodiment will be described. The CMM creation process and the first merging process (see FIG. 5) executed in the image forming apparatus 20 are basically the same as those in the first embodiment. However, the control unit 21 of the image forming apparatus 20 executes the new CMM creation process shown in FIG. 13 instead of step S3 of the first merging process.

[0086] The objects extracted in step S1 of the first merging process are defined as the first object and the second object. The CMMs selected in step S2 of the first merging process are designated as CMM1 and CMM2.

[0087] L of the color area corresponding to the first object * a * b * The coordinates in the color space are (L1 * ,a1 * ,b1 * ), L of the color area corresponding to the second object * a * b * The coordinates in the color space are (L2 * ,a2 * ,b2 * ) are used as the coordinates of each color area. The coordinates of the representative point in each color area, determined by some method, are used. For example, the average coordinates of each color area may be used as the coordinates of each color area. * a * b * The values ​​can be converted into each other using known formulas. * a * b * The value can be calculated from the XYZ values ​​of the color area corresponding to each object. * a * b * Since the color space makes it easy to recognize the degree of color difference, we use L * a * b * Use the value.

[0088] In the new CMM creation process, the control unit 21 calculates the L of the color area corresponding to the first object. * a * b * Coordinates in color space (L1 * ,a1 * ,b1 * ) is acquired (step S21).

[0089] Next, the control unit 21 calculates the L of the color area corresponding to the second object. * a * b * Coordinates in color space (L2 * ,a2 * ,b2 * ) is acquired (step S22).

[0090] Next, the control unit 21 * a * b * A distance D between the color area corresponding to the first object and the color area corresponding to the second object in the color space is calculated (step S23). The distance D between the objects is calculated by the following formula (1).

number

[0091] Next, the control unit 21 determines whether the distance D between the objects is less than a first threshold value α (step S24). That is, the control unit 21 determines whether the distance D between the objects satisfies the condition of the following formula (2).

number

[0092] If the distance D between the objects is less than the first threshold value α (step S24; YES), the control unit 21 does not merge the CMM1 corresponding to the first object with the CMM2 corresponding to the second object (step S25), and uses the CMM1 or CMM2 as a new CMM (step S26).

[0093] In step S24, if the distance D between the objects is not less than the first threshold value α (step S24; NO), the control unit 21 determines whether the distance D between the objects is equal to or greater than the first threshold value α and equal to or less than the second threshold value β (step S27). That is, the control unit 21 determines whether the distance D between the objects satisfies the condition of the following formula (3).

number

[0094] If the distance D between the objects is equal to or greater than the first threshold α and equal to or less than the second threshold (step S27; YES), the process proceeds to step S28. In step S28, the control unit 21 averages the CMM1 corresponding to the first object and the CMM2 corresponding to the second object for the color region corresponding to the first object and the color region corresponding to the second object in the XYZ color space.

[0095] Referring to FIG. 14, a method for creating a new CMM43 by averaging CMM1 and CMM2 will be described. CMM1 is optimally adjusted for color conversion of a color gamut 35 corresponding to the first object. CMM2 is optimally adjusted for color conversion of a color gamut 36 corresponding to the second object. The control unit 21 uses the color conversion table of CMM1 as a base. In the color gamut 35, the control unit 21 averages the grid point data of CMM1 and the grid point data of CMM2, and sets the averaged data (CMYK values) as the output value of the new CMM43. In the color gamut 36, the control unit 21 averages the grid point data of CMM1 and the grid point data of CMM2, and sets the averaged data (CMYK values) as the output value of the new CMM43. Note that the control unit 21 uses the color conversion table of CMM1 for the CMM43 in the portions other than the color gamuts 35 and 36 in the XYZ color space.

[0096] In step S27, if the distance D between the objects is not equal to or greater than the first threshold value α and not equal to or less than the second threshold value β (step S27; NO), the process proceeds to step S29. That is, if the distance D between the objects satisfies the condition of the following formula (4), the process proceeds to step S29.

number

[0097] In step S29, the control unit 21 replaces the color area corresponding to the second object with the grid point data of the CMM2 based on the CMM1 corresponding to the first object. After step S26, step S28, or step S29, the new CMM creation process ends.

[0098] In step S24, control unit 21 determines whether distance D is less than first threshold value α. Alternatively, control unit 21 may determine whether distance D is equal to or less than first threshold value α. In other words, when distance D is equal to first threshold value α, control unit 21 may proceed to step S25 instead of step S27. In step S27, control unit 21 determines whether distance D is equal to or less than second threshold value β. Alternatively, control unit 21 may determine whether distance D is less than second threshold value β. In other words, when distance D is equal to second threshold value β, control unit 21 may proceed to step S29 instead of step S28.

[0099] As described above, according to the third embodiment, similar to the first embodiment, the control unit 21 of the image forming apparatus 20 can reduce the workload on the user in creating color conversion parameters.

[0100] When the distance between the color region corresponding to the first object and the color region corresponding to the second object in the color space is less than a first threshold, the control unit 21 does not merge the first color conversion parameters with the second color conversion parameters. The control unit 21 can reduce the processing load by using either the first color conversion parameters or the second color conversion parameters as is.

[0101] When the distance between the color region corresponding to the first object and the color region corresponding to the second object in the color space is equal to or greater than a first threshold and equal to or less than a second threshold, the control unit 21 averages the first color conversion parameters and the second color conversion parameters for the color region corresponding to the first object and the color region corresponding to the second object in the color space. This allows the control unit 21 to create color conversion parameters that do not deviate significantly from either the first color conversion parameters or the second color conversion parameters.

[0102] The above-described embodiments are merely examples of the color conversion parameter creation device, image forming system, color conversion parameter creation method, and program according to the present invention, and are not intended to limit the scope of the present invention. The detailed configuration and operation of each component of the device may also be modified as appropriate without departing from the spirit of the present invention. For example, characteristic processes in each embodiment may be combined and executed.

[0103] In the above embodiments, the case where the control unit 21 of the image forming apparatus 20 acquires a CMM stored in the cloud server 10 and creates a new CMM has been described. However, the control unit 21 does not need to download the color conversion execution function from the cloud server 10. In other words, it is sufficient that the cloud server 10 stores color conversion parameters (color conversion profile, color conversion table). The control unit 21 simply acquires two or more color conversion parameters to be used from the cloud server 10 and creates new color conversion parameters.

[0104] In the above embodiments, the description has focused on color conversion parameters (printer profile) for color converting image data that is the subject of image formation in the image forming unit 25 of the image forming apparatus 20. Alternatively, the created color conversion parameters may be color conversion parameters (monitor profile) for color converting image data to be displayed on a monitor. Also, the created color conversion parameters may be color conversion parameters (scanner profile) for color converting image data read by a scanner.

[0105] In the above embodiments, the case where the CMM (color conversion parameters) is stored in the cloud server 10 has been described. Alternatively, color conversion parameters that have been created so far may be stored in the storage unit 29 of the image forming device 20. Furthermore, the control unit 21 of the image forming device 20 may acquire color conversion parameters stored in another image forming device 20.

[0106] In the above embodiments, the control unit 21 of the image forming apparatus 20 automatically selects color conversion parameters corresponding to the objects. Alternatively, the user may select color conversion parameters corresponding to each of two or more objects included in the image data to be processed from the color conversion parameters stored in the cloud server 10. In other words, the control unit 21 may select color conversion parameters manually selected by the user as color conversion parameters corresponding to the objects.

[0107] In each of the above embodiments, the image forming apparatus 20 creates a new CMM (color conversion parameter), but the new CMM may be created on the cloud server 10 side. Then, the image forming apparatus 20 may obtain the new CMM from the cloud server 10 and use it for color conversion.

[0108] In the above embodiments, the case where the object for which a CMM is suitable is managed in the management table 151 of the cloud server 10 has been described. Alternatively, the file name of each CMM may include the target object. Furthermore, thumbnail images (images of apples, melons, etc.) representing target objects may be stored in association with each CMM in storage unit 15 of cloud server 10. When each image forming device 20 uses each CMM stored in cloud server 10, control unit 21 may cause display unit 23 to display the thumbnail images. This allows the user to confirm the object or color corresponding to the CMM.

[0109] Furthermore, the processing performed by the image forming apparatus 20 in each of the above embodiments may be performed by an external device (such as a computer) that can communicate with the image forming apparatus 20. Furthermore, the processing performed by the image forming apparatus 20 in each of the above embodiments may be performed by multiple devices working together. Furthermore, the processing performed by the image forming apparatus 20 in each of the above embodiments may be performed by one or multiple devices that constitute the image forming system 100.

[0110] The computer-readable medium for storing the program for executing each process is not limited to the above examples. A carrier wave may also be used as a medium for providing program data via a communication line.

[0111] The above-disclosed embodiments are for the purpose of explanation and example only, and are not intended to be limiting. The scope of the present invention should be interpreted by the claims. [Explanation of symbols]

[0112] 10. Cloud Server 11 Control section 12 ROM 14 Communications Department 15 Storage section 20(20A,20B,20C,...) Image forming device 21 Control section 22 Control section 23 Display section 24 Image reading unit 25 Image forming unit 26 ROM 28 Communications Department 29 Memory section 100 Image forming system 151 Management Table N Communication Network

Claims

1. a selection means for selecting two or more color conversion parameters from a plurality of color conversion parameters stored in a storage means; a creating means for merging the two or more selected color conversion parameters to create new color conversion parameters; A color conversion parameter creation device comprising:

2. 2. The color conversion parameter creating device according to claim 1, further comprising color conversion means for converting the color of image data to be processed using the new color conversion parameters.

3. 3. The color conversion parameter creating device according to claim 2, further comprising a correcting means for correcting the new color conversion parameters when the color conversion result using the new color conversion parameters is not appropriate.

4. 4. The color conversion parameter creating device according to claim 3, wherein said correcting means narrows data intervals in color regions in the color space where the color conversion results are inappropriate for the new color conversion parameters.

5. 2. The color conversion parameter creation device according to claim 1, wherein the selection means extracts two or more objects contained in the image data to be processed, and selects the two or more color conversion parameters corresponding to each of the two or more extracted objects.

6. 2. The color conversion parameter creating device according to claim 1, wherein the selection means selects the two or more color conversion parameters for each page of the image data to be processed.

7. the selecting means selects a first color conversion parameter corresponding to a first object and a second color conversion parameter corresponding to a second object; 2. The color conversion parameter creation device according to claim 1, wherein the creation means does not merge the first color conversion parameters with the second color conversion parameters when the distance between the color area corresponding to the first object and the color area corresponding to the second object in the color space is less than a first threshold value.

8. 8. The color conversion parameter creation device of claim 7, wherein the creation means averages the first color conversion parameter and the second color conversion parameter for a color region corresponding to the first object and a color region corresponding to the second object in a color space when the distance is greater than or equal to the first threshold and less than or equal to the second threshold.

9. a storage means for storing a plurality of color conversion parameters; a selection means for selecting two or more color conversion parameters from the plurality of color conversion parameters stored in the storage means; a creating means for merging the two or more selected color conversion parameters to create new color conversion parameters; a color conversion means for converting the color of image data to be processed using the new color conversion parameters; an image forming means for forming an image based on the color-converted image data; An image forming system comprising:

10. a selection step of selecting two or more color conversion parameters from a plurality of color conversion parameters stored in a storage means; a creation step of merging the two or more selected color conversion parameters to create new color conversion parameters; A method for creating color conversion parameters, including:

11. Computer, a selection means for selecting two or more color conversion parameters from a plurality of color conversion parameters stored in a storage means; a creating means for merging the two or more selected color conversion parameters to create new color conversion parameters; A program to function as a

Images