JP2011018982A - Image processing apparatus and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow even a general program to edit image data for special printing.SOLUTION: The image processing apparatus includes: an image editing means which edits first image data comprising main image data having pixels wherein color gradation values indicative of colors are stored, and layer image data wherein pixels are arrayed in the same manner as the main image data; an image editing indication means which instructs the image editing means to store information indicative of whether each pixel of the main image data is a special pixel or not into the pixel of the layer image data; and a conversion means which specifies special pixels in the main image data on the basis of the layer image data and stores indexes associated with ink amounts for use in a printer, instead of color gradation values with respect to the specified special pixels and generates second image data wherein flags showing the special pixels are stored.

Description

  The present invention relates to an image processing apparatus and an image processing method, and more particularly to an image processing apparatus and an image processing method capable of editing main image data and layer image data.

  In order to cause the printer to perform special printing, the printer driver may use image data in a dedicated format (see Patent Document 1). For example, when printing paint samples or company logos, it is necessary to faithfully reproduce not only general color matching (maintaining color matching) but also spectral reflectance characteristics. Causes the printer driver to perform special printing (spot color printing) using the image data. Specifically, the spectral reflectance characteristics in these printed materials are reproduced by directly specifying the amount of ink used when the printer prints a paint sample, a company logo, or the like.

JP 2002-223363 A

  However, since the format of such image data depends on the printer manufacturer and the printer model, there is a problem that editing and processing cannot be performed by a general image editing program or image creation program. Printer manufacturers must separately provide image editing programs and image creation programs that can edit and process image data in a dedicated format. On the other hand, there is an inconvenience that the printer cannot execute special printing using image data edited and processed by an image editing program or image creation program that is familiar to users.

  The present invention has been made in view of the above problems, and provides an image processing apparatus and an image processing method capable of editing image data for spot color printing even with a general program.

  The image processing apparatus according to the present invention includes at least an image editing unit, an image editing instruction unit, and a conversion unit. The image editing unit edits first image data including main image data having pixels for storing color gradation values indicating colors and layer image data in which pixels are arranged in the same manner as the image data. The pixels of the main image data and the layer image data correspond to each other, and conceptually, the layer image data can be layered on the main image data. The image editing instruction unit instructs the image editing unit to store, in each pixel of the layer image data, information indicating whether each pixel of the main image data is a spot color pixel. The type of the layer image data that can be edited by the image editing unit differs depending on the image editing unit, but if the image editing program has a function of editing any type of layer, the function is used. The layer image data can be edited. For example, the layer image data can be realized by an alpha channel of the main image data or can be realized by an arbitrarily addable layer.

  The converting means specifies the spot color pixel in the main image data based on the layer image data. Next, an index associated with the amount of ink to be used by the printing apparatus is stored for the specified spot color pixel instead of the color gradation value. Further, second image data in which a flag indicating the spot color pixel is stored is generated for the specified spot color pixel. The ink amount of the present invention means the amount of color material that determines image formation by printing, and includes, for example, the amount of toner. Although the second image data is data having a special format, the image editing means converts the first image data into the second image data by providing the converting means for converting the first image data into the second image data. It only needs to have a function to edit. That is, the image editing unit only needs to have a function of editing any kind of layer, and the image editing unit can be realized by executing a general image editing program.

  When printing based on the second image data, it is preferable to have the following configuration. That is, profile acquisition means for acquiring a first conversion profile that defines the correspondence between the index and the ink amount, and a second conversion profile that defines the correspondence between the color gradation value and the ink amount; In the second image data, for the pixel in which the index is stored, the index is converted into the ink amount by referring to the first conversion profile, and for the pixel in which the index is not stored, the pixel is stored. Color conversion means for generating ink amount image data in which each pixel stores the ink amount by converting the color gradation value into the ink amount by referring to the second conversion profile is further provided. In this way, color conversion processing can be executed for the spot color pixels and other pixels, and image formation by the printing apparatus can be controlled based on the ink amount obtained by the color conversion processing. .

  As a method for storing the index in the first image data, the following method can be employed. A first method is to store the index as the name of the layer image data. By doing so, the index can be stored in the first image data even when each pixel of the layer image data cannot secure a data capacity sufficient to store the index. When it is necessary to store a plurality of the indexes, a plurality of the layer image data may be generated and a plurality of the indexes may be assigned to the respective names. As a second method, the index is stored as a gradation value of each pixel in the layer image data. When each pixel of the layer image data can secure a data capacity sufficient to store the index, the second method can be adopted.

  Further, user convenience can be improved by allowing the index to be stored in the first image data to be visually specified. For example, the image editing instruction means receives the designation of the color sample displayed on the display device, and stores the index corresponding to the designated color indicated by the designated color sample in the first image data. Also good. The designated color may correspond to a color indicated under a designated light source when a printed material is printed with the ink amount corresponding to the index. Since the ink amount uniquely corresponds to the index, the spectral reflectance characteristics when printing according to the index can be uniquely specified. Therefore, the specified light source and the specified color can be received, and the index corresponding to the ink amount from which a printed matter showing the specified color can be obtained under the specified light source can be associated.

  In the case where the image editing unit, the image editing instruction unit, and the conversion unit are specifically implemented using a computer, the following configuration is preferable. That is, the image editing means is provided by an image editing program, and the image editing instruction means and the conversion means are provided by a plug-in module incorporated in the image editing program. The process relating to the spot color can be realized by the plug-in module, and any image editing program capable of handling the first image data can be used.

It is a block diagram which shows the hardware constitutions of a computer. It is a block diagram which shows the software configuration of a computer. It is a flowchart which shows the flow of an image process. It is a figure which shows an example of UI image. It is a figure which shows an example of a format table. It is a flowchart which shows the flow of a file expansion | deployment process. It is a schematic diagram which shows the structure of 2nd image data. It is a figure which shows an index table. It is a schematic diagram which shows the structure of the 1st image data in the case of the classification | category B. FIG. It is a schematic diagram which shows the structure of the 1st image data in the case of the classification C. It is a flowchart which shows the flow of a special color edit process. It is a figure which shows an example of UI image on which the special color palette was displayed. It is a flowchart which shows the flow of a file output process. 6 is a flowchart illustrating a flow of print control processing. It is a figure which shows the software structure for an index table creation process. It is a flowchart of an index table creation process. It is a schematic diagram which shows the printing system of a printer. It is a figure which shows a spectral reflectance database. It is a figure which shows a spectral Neugebauer model. It is a figure which shows a cell division | segmentation Yule-Nielsen spectroscopic Neugebauer model. It is a flowchart which shows the flow of a special color edit process. It is a figure which shows the index table concerning a modification.

Hereinafter, embodiments of the present invention will be described in the following order.
1. Configuration of image processing device:
2. Image processing flow:
2-1. File expansion processing:
2-1-1. File expansion for category A:
2-1-2. File expansion for category B:
2-1-3. File expansion for category C:
2-2. Special color editing process:
2-2-1. Special color editing for category A:
2-2-2. Special color editing for category B:
2-2-3. Special color editing for category C:
2-3. File output processing:
2-3-1. File output for category A:
2-3-2. File output for category B:
2-3-3. File output for category C:
3. Print control processing:
4). About index tables:
4-1. About creating an index table:
5. Spectral printing model:
6). Variation:

1. Configuration of image processing device:
FIG. 1 shows an example of a hardware configuration of a computer 10 constituting an image processing apparatus according to the present invention or a part thereof. The computer 10 includes a CPU 11, a RAM 12, a ROM 13, a hard disk drive (HDD) 14, a video interface (I / F) 16, an input device interface (I / F) 17, a general-purpose interface (I / F) 18, and a bus 19. Has been. The CPU 11 expands the program data PD stored in the ROM 13 and the HDD 14 in the RAM 12 and performs calculations for executing processes and functions described later. The video I / F 16 executes a process for outputting video to an external display 16a. The input device I / F 17 receives an operation on the external keyboard 17a and the mouse 17b, and transmits a signal based on the operation to the CPU 11. A printer 20 and a spectral reflectometer 30 are connected to the general-purpose I / F 18. The HDD 14 stores a format table T1, an index table IDT, and a color conversion table LUT. The index table IDT corresponds to the first conversion profile of the present invention, and the color conversion table LUT corresponds to the second conversion profile of the present invention.

  FIG. 2 is a block diagram illustrating a configuration of a program group executed by the computer 10 according to the present embodiment. The computer 10 executes an OS (operating system) (not shown), and an image editing program P1, a plug-in module P2, and a printer driver P3 are executed on the OS. The plug-in module P2 and the printer driver P3 are associated with the image editing program P1 at the time of installation or the like, and the plug-in module P2 and the printer driver P3 can be activated in response to an operation on the image editing program P1. Yes. In the state where the image editing program P1, the plug-in module P2, and the printer driver P3 are activated, various commands and data are exchanged. In the present embodiment, a plurality of image editing programs P1 (AP1 to AP3) are installed in the computer 10, all of which are associated with the plug-in module P2 and the printer driver P3.

  The image editing program P1 has a UI part P1a, a file development part P1b, a main image editing part P1c, a layer editing part P1d, and a file output part P1e. The main image editing unit P1c and the layer editing unit P1d correspond to the image editing unit of the present invention. The plug-in module P2 includes a monitoring unit P2a, a UI instruction unit P2b, a main image editing instruction unit P2c, a layer editing instruction unit P2d, a format conversion unit P2e, and a determination unit P2f. The printer driver P3 includes a color conversion unit P3a, a halftone unit P3b, and a print data generation unit P3c. The main image editing instruction unit P2c and the layer editing instruction unit P2d correspond to the image editing instruction unit of the present invention, and the format conversion unit P2e corresponds to the conversion unit of the present invention.

  When the plug-in module P2 is activated, the plug-in module P2 is also activated, and the monitoring unit P2a of the plug-in module P2 constantly monitors the operation of the plug-in module P2. In response to the monitoring by the monitoring unit P2a, the UI instruction unit P2b of the plug-in module P2 edits the display image data DID on the RAM 12 to be displayed by the UI unit P1a of the image editing program P1, and the UI of the image editing program P1. The part P1a gives an instruction for an operation to be accepted. In response to the monitoring by the monitoring unit P2a, the main image editing instruction unit P2c and the layer editing instruction unit P2d of the plug-in module P2 respectively send main image data on the RAM 12 to the main image editing unit P1c and the layer editing unit P1d. An instruction to edit the MID and the layer image data AID is issued. Further, in response to the monitoring by the monitoring unit P2a, the format conversion unit P2e of the plug-in module P2 converts the format of the second image data SID stored in the HDD 14 into the first image data FID. The converted first image data FID is expanded on the RAM 12 as main image data MID and layer image data AID by the file expansion unit P1b of the image editing program P1.

  In response to the monitoring by the monitoring unit P2a, the format conversion unit P2e of the plug-in module P2 converts the format of the first image data FID developed in the RAM 12 into the second image data SID. The converted second image data SID is stored in the HDD 14 by the file output unit P1e of the image editing program P1 or is output to the printer driver P3. The color conversion unit P3a, the halftone unit P3b, and the print data generation unit P3c sequentially process the second image data SID output to the printer driver P3, whereby the printer 20 executes printing. The discrimination unit P2f of the plug-in module P2 acquires the classification of the format of the image data that can be handled by the image editing program P1 upon activation, and stores the format flag FL corresponding to the classification on the RAM 12. The UI instruction unit P2b, main image editing instruction unit P2c, layer editing instruction unit P2d, and format conversion unit P2e of the plug-in module P2 determine the format flag FL on the RAM 12, and execute different operations according to the format flag FL. To do. Hereinafter, the processes executed by the programs P1 to P3 will be described sequentially.

2. Flow of Image Processing FIG. 3 is a flowchart showing the flow of image processing according to the present embodiment. This image processing is started in response to activation of any one of the image editing programs P1. When the image editing program P1 is activated, the UI unit P1b displays a UI image on the display 16a and monitors the operation of the mouse 17b and the keyboard 17a (step S105). At the same time, the plug-in module P2 is activated, the monitoring unit P2a starts monitoring the image editing program P1, and the UI instruction unit P2b starts an instruction for display and operation reception by the UI unit P1b (step S110). In the present embodiment, a process for editing the second image data SID stored in advance in the HDD 14 will be described as an example.

  FIG. 4 shows an example of a UI image displayed by the UI part P1b and the UI instruction part P2b. A file development button B1, a spot color edit start button B2, a spot color edit end button B3, a file save button B4, and a print execution button B5 are provided above the UI image, and a preview area W1 is provided in the center. . The special color edit start button B4 and the special color edit end button B5 are displayed when the UI instruction unit P2b instructs the UI unit P1b. The determination unit P2f of the plug-in module P2 acquires the classification of the format of the first image data FID that can be handled by the image editing program P1 activated by the plug-in module P2 (step S115). The format of the data stored in the HDD 14 or RAM 12 for the first image data FID to be processed by each image editing program P1 is determined in advance, and a format table T1 specifying the format for each image editing program P1 is registered in the HDD 14. Has been. The determination unit P2f refers to the format table T1 to acquire the classification of the format of the first image data FID for the image editing program P1 that has requested activation.

  FIG. 5 is a diagram illustrating an example of the format table T1. In this embodiment, three types of applications AP1 to AP3 are installed as the image editing program P1, and the format of the first image data FID is registered for each of the applications AP1 to AP3. The format table T1 is added when the applications AP1 to AP3 are installed. According to such a format table T1, the format of the first image data FID that can be handled by each of the applications AP1 to AP3 can be acquired. Note that the determination unit P2f may inquire the format of the first image data FID that can be handled with respect to the image editing program P1 activated by the plug-in module P2. As shown in the format table T1, in this embodiment, the format of the first image data FID that can be handled by each of the three types of applications AP1 to AP3 is classified into three types (classification A to classification C).

  In the category A, there is an image editing program P1 (AP1) in which bitmap data in which each pixel has RGBX gradation values can be handled as the first image data FID and the X gradation values can be edited. being classified. For category B, bitmap data in which each pixel has a color gradation value in the RGB color space can be handled as the first image data FID, and a layer in which each pixel can store 24-bit data can be added. Image editing program P1 (AP2) is classified. In this specification, when a gradation value represents a color, it shall be expressed as a color gradation value. Note that the layer may be composed of a plurality of channels, and it is sufficient that 24-bit data can be stored in all channels. Of course, the layer may be constituted by a single channel, and 24-bit data may be stored in the single channel. For classification C, only a layer in which bitmap data in which each pixel has a color gradation value in the RGB color space can be handled as the first image data FID and each pixel can store data smaller than 24 bits is created. The image editing program P1 (AP3) that cannot be classified is classified. Usually, the image editing program P1 can handle a plurality of types of first image data FID, and a single image editing program P1 may correspond to a plurality of classifications A to C. In such a case, classification A is applied with priority over classification B and classification C, and classification B is applied with priority over classification C. In the present embodiment, the formats of the first image data FID that can be handled by the applications AP1 to AP3 are classified into categories A to C, respectively. Next, the determination unit P2f stores the format flag FL (ac) that can identify the acquired classifications A to C at a predetermined address in the RAM 12 (step S120).

  The UI unit P1b and the monitoring unit P2a detect clicks of the file development button B1 (step S125), the spot color editing start button B2 (step S130), the file save button B4, and the print execution button B5 (step S135). When the file development button B1 and the spot color editing start button B2 are clicked, a file development process (from step S150) and a spot color editing process (from step S170) are executed. When the file save button B4 and the print execution button B5 are clicked, a file output process (step S190-) is executed. In the spot color editing process (steps S170 and after), the click of the spot color editing end button B3 is detected, and when the click is detected, the spot color editing process is ended. Next, the file expansion process (from step S150) executed when the file expansion button B1 (step S125) is clicked will be sequentially described.

2-1. File expansion processing:
FIG. 6 is a flowchart showing the flow of the file development process (step S150 and subsequent steps). The file expansion process is a process of converting the second image data SID into the first image data FID that can be handled by the image editing program P1. Since the first image data FID that can be handled by the image editing program P1 differs depending on the classifications A to C, different processing is performed based on the format flag FL. First, the UI part P1a of the image editing program P1 accepts an operation for selecting the second image data SID to be processed (step S150). At this time, the monitoring unit P2a of the plug-in module P2 detects that the second image data SID is selected, and the format conversion unit P2e acquires the selected second image data SID from the HDD 14 (step S151). Next, the format converter P2e determines whether or not a spot color pixel is included in the second image data SID (step S152).

  FIG. 7 schematically shows the structure of the second image data SID. The second image data SID is so-called RGB bitmap data, and pixels capable of storing 8-bit color gradation values for each RGB channel are arranged in a matrix. Basically, the color indicated by each pixel can be expressed by combining RGB color gradation values for each pixel. In this embodiment, it is assumed that the RGB color gradation values conform to the CIE standard sRGB color system. The second image data SID can store the X channel X gradation value (8 bits) in addition to the RGB channel in each pixel. Therefore, the amount of data stored in each pixel is 4 bytes. Although 255 gradations can be expressed by the X gradation value, in this embodiment, either 0 or 1 is stored as the X gradation value.

  A pixel with an X gradation value of 0 means a normal pixel, and a pixel with an X gradation value of 1 means a spot color pixel. That is, the X gradation value 1 corresponds to the flag of the present invention. In the normal pixel, as described above, the color indicated by the normal pixel is expressed by the combination of the color gradation values of the RGB channels. On the other hand, in the special color pixel, the index IDX is expressed by a combination of RGB channel gradation values. In this embodiment, the index IDX is a serial number that increases by 1 from 0, and treats the gradation values of the RGB channels of 8 bits each (for example, the bit strings of the gradation values of the RGB channels are simply connected). This makes it possible to store an index IDX in a 24-bit representation. Note that the second image data SID only needs to be expanded into the RGB bitmap data format shown in FIG. 7 at least at the time of editing, and may be compressed or the like when stored in the HDD 14.

  In step S152, the X gradation value of all the pixels is examined, and it is determined whether or not the X gradation value is 1 even for one pixel. If the X gradation value of one pixel is not 1, the second image data SID is transferred as it is to the file development unit P1b of the image editing program P1 as the first image data SID (step S153). If none of the pixels has an X gradation value of 1, the second image data SID is normal RGB image data, so that the file expansion unit P1b of the image editing program P1 can expand it as it is (step S160). Next, the determination unit P2f refers to the format flag FL on the RAM 12 to determine the classifications A to C of the image editing program P1 (step S155). Up to this point, the processing is common to the classifications A to C. When even one pixel having an X gradation value of 1 is present, different processing is executed for each of the classifications A to C. Hereinafter, the file expansion processing of the classifications A to C will be described in order. For processing common to the categories A to C, nothing is added after the 3-digit step number, and for processing unique to the categories A to C, A to C are added after the 3-digit step number, respectively. , B, classifications B and C, and classifications C and A, the processes common to the classifications C and A are respectively appended with AB, BC, and CA after the 3-digit step number.

2-1-1. File expansion for category A:
The fact that the image editing program P1 is classified as A means that the image editing program P1 can handle bitmap data in which each pixel has RGBX gradation values as the first image data FID. No conversion is performed on the image data SID itself. That is, the format conversion unit P2e uses the second image data SID as it is as the first image data FID (step S156A). Note that each pixel can be treated as the first image data FID having RGBX gradation values. The image editing program P1 develops the gradation values of any RGBX channel in the RAM 12 based on its own function. It means that it can be edited above. Next, the format conversion unit P2e transfers the first image data FID to the file development unit P1b of the image editing program P1 (step S159).

  In the case of the classification A, the file development unit P1b can develop the second image data SID as it is as the first image data FID, and can develop the main image data MID having RGBX gradation values in the RAM 12 (Step S1). S160). The main image data MID expanded in the RAM 12 can be edited including the X gradation value. Next, the UI instruction unit P2b detects a spot color pixel having an X tone value of 1, and acquires an index IDX based on the RGB tone value for each spot color pixel. Further, the UI instruction unit P2b displays the display image data DID obtained by replacing the RGB gradation values of the respective special color pixels with the display RGB color gradation values associated with the index IDX in the index table IDT stored in the HDD 14. Is generated (step S161A), and a display instruction is output to the UI part P1b to display in the preview area W1 (step S162A). The UI unit P1b can display the display image data DID in the preview area W1 by performing display according to the display instruction (step S163).

FIG. 8 is a diagram showing the index table IDT. In the index table IDT, for each index IDX assigned to each paint, an RGB color gradation value for display, an ink amount set φ comprising CMYKlclm ink amount (8 bits), and a target spectral reflectance R _t (λ). Are stored in association with each other. A method for creating the index table IDT will be described later. Each index IDX is associated with a unique paint, and the ink amount set φ of each index IDX is a combination of ink amounts that can reproduce the spectral reflectance of the corresponding paint. The RGB color gradation value for display of each index IDX represents the color indicated by the paint when the corresponding paint is irradiated with a predetermined light source (for example, CIE-D65 standard light source) by the RGB color gradation value in the sRGB color space. Is. Since the RGB gradation of the spot color pixel represents the index IDX and does not represent a color in the normal sRGB color space, even if the second image data SID is expanded as it is, a normal color is displayed for the spot color pixel on the display 16a. Cannot be reproduced. In the display image data DID, since the RGB gradation value indicating the index IDX in the special color pixel is replaced with the display RGB color gradation value, normal display can be performed on the display 16a.

2-1-2. File expansion for category B:
When the image editing program P1 is classified as B, RGBX gradation values cannot be handled as they are, so that effective conversion of the second image data SID is necessary. The format conversion unit P2e replaces all X gradation values of the second image data SID with 0. Further, the main image data MID is generated by replacing the RGB gradation value indicating the index IDX in the special color pixel with the display RGB color gradation value corresponding to the index IDX in the index table IDT (step S156BC). ). In the second image data SID, the normal pixel having the X gradation value of 0 stores the gradation value of 0, and the special color pixel having the X gradation value of 1 is an index based on the RGB gradation value of the special color pixel. Layer image data AID storing IDX (24 bits) is generated (step S157B).

  Further, the first image data FID is generated by attaching to the main image data MID and the layer image data AID (step S158BC). At this time, the layer image data AID is attached to the main image data MID. The layer image data AID is attached with a parameter for designating that direct editing and display are impossible. Even when the image editing program P1 is classified as B, the layers that can be handled as the layer image data AID differ depending on the image editing program P1. For example, when layer image data AID as an alpha channel can be handled, the layer image data AID is attached to the main image data MID as an alpha channel. For the image editing program P1 to which an arbitrary layer can be added according to the operation of the user or the like, the layer image data AID is attached to the main image data MID as an added layer. Layer information that can be handled by the image editing program P1 is registered in the format table T1 in association with each image editing program P1 (AP1 to AP3).

  FIG. 9 is a schematic diagram showing the structure of the first image data FID generated when the image editing program P1 is classification B. The main image data MID is RGB bitmap data in which each pixel stores RGB color gradation values. In particular, display RGB color gradation values are stored in the special color pixels in the main image data MID. The layer image data AID is composed of pixels corresponding to the respective pixels of the main image data MID, and a gradation value (235, 1005) meaning an index IDX is stored for the special color pixel. On the other hand, the gradation value 0 is stored for the normal pixels in the layer image data AID.

  The first image data FID converted as described above is transferred to the file development unit P1b of the image editing program P1 (step S159). As a result, the file development unit P1b can develop the main image data MID and the layer image data AID constituting the first image data FID in the RAM 12 (step S160), and the main image data MID and the layer image data AID. Each can be edited. Since the image editing program P1 of category B can handle a 24-bit layer for each pixel, the layer image data AID can also be expanded in the RAM 12 as a layer. The main image data MID only needs to store RGB color gradation values at the time of development, and the RGB color gradation values of each pixel are converted into CMYK color gradations according to the settings and specifications of the image editing program P1. The value may be converted into an RGB color gradation value in another RGB color space, etc., and developed in the RAM 12. The UI instruction unit P2b outputs a display instruction to the UI unit P1b to display the main image data MID as it is in the preview area W1 (step S162BC). Then, the UI unit P1b performs display according to the display instruction (step S163). Since the RGB gradation value (display RGB color gradation value) of each pixel (special color pixel and normal pixel) of the main image data MID is a color gradation value indicating a color, the UI unit P1b displays the main image data MID. Can be displayed as they are.

2-1-3. File expansion for category C:
Even when the image editing program P1 is classified as C, RGBX gradation values cannot be handled as they are, so that practical conversion is necessary. The format conversion unit P2e replaces all X gradation values of the second image data SID with 0. Further, the main image data MID is generated by replacing the RGB gradation value indicating the index IDX in the special color pixel with the display RGB color gradation value corresponding to the index IDX in the index table IDT (step S156BC). ). The format conversion unit P2e then stores the number of types of index IDX stored as RGB gradation values in the special color pixels in the second image data SID (the number of different index IDX (the number of combinations of the RGB gradation values of the special color pixels ( Layer image data AID corresponding to the number of colors) is generated (step S157C).

  For example, when there are three types of index IDX stored in the spot color pixel in the second image data SID, three layer image data AID are generated in association with the three types of index IDX. In each layer image data AID, the gradation value 1 is stored for the special color pixel in which the index IDX corresponding to the layer image data AID is stored, and the gradation value 0 is stored for the other pixels. Then, the first image data FID is generated by attaching the layer image data AID to the main image data MID (step S158BC). At this time, each layer image data AID is attached to the main image data MID as a layer, and the name of the layer is an index IDX associated with each layer image data AID. Further, a parameter for designating that direct editing and display are impossible is attached to each layer of the layer image data AID.

  FIG. 10 schematically shows the structure of the first image data FID generated when the image editing program P1 is classification C. The main image data MID is the same as in the case of classification B. On the other hand, the layer image data AID is generated by the number (2) of the index IDX stored in the spot color pixel in the second image data SID. In each layer image data AID, a gradation value 1 is stored only for pixels that are special color pixels and store the corresponding index IDX, and a gradation value 0 is stored for the other pixels. The name of each layer image data AID is an index IDX (235, 1005) corresponding to each layer image data AID.

  The first image data FID converted as described above is transferred to the file development unit P1b of the image editing program P1 (step S159). As a result, the file development unit P1b can develop the main image data MID and the layer image data AID constituting the first image data FID in the RAM 12 (step S160), and the main image data MID and the layer image data AID. Each can be edited. The UI instruction unit P2b outputs a display instruction to the UI unit P1b to display the main image data MID as it is in the preview area W1 (step S162BC). Then, the UI unit P1b performs display according to the display instruction (step S163). That is, the UI unit P1b displays the main image data MID as it is in the preview area W1.

2-2. Special color editing process:
By the file expansion process described above, the main image data MID and the layer image data AID are expanded on the RAM 12 as the first image data FID in a format that can be handled by the image editing programs P1 of classifications A to C. On the display 16a, an image based on the display image data DID (class A) or the main image data MID (class B, C) is displayed in the UI image preview area W1 shown in FIG. In this embodiment, a photographic image (indoor image) obtained by photographing furniture or a wall of a room is displayed in the preview area W1. In the image processing of FIG. 3, the click of the spot color editing start button B2 is detected (step S130), and when the click is detected, the spot color editing process (steps S170 to) is executed.

  FIG. 11 is a flowchart showing the flow of the spot color editing process (from step S170). First, the UI unit P1a of the image editing program P1 accepts an area designation in the UI image preview area W1 (step S170). At this time, the monitoring unit P2a of the plug-in module P2 detects that the region has been designated, and in response to this, the main image editing instruction unit P2c and the layer editing instruction unit P2d acquire the designated region (step S171). ). The area designation may be performed, for example, by dragging and dropping the mouse 17b at an arbitrary position in the preview area W1 (for example, dragging at the upper left corner of the designated rectangular area and dropping at the lower right corner), or the preview area W1. This may be done by clicking on the special color pixel. In the former case, a special color area where a special color pixel is arranged can be newly designated, and in the latter case, an existing special color area can be designated. When the area designation is accepted, the UI instruction unit P2b outputs data for displaying the special color palette PL as a UI image to the UI unit P1a (step S172). The UI unit P1a displays the special color palette PL (step S173).

  FIG. 12 is a diagram illustrating an example of a UI image on which the special color palette PL is displayed. In the spot color palette PL, a plurality of rectangular color samples CS are arranged. Each color sample CS is displayed based on a uniform RGB color gradation value, and the RGB color gradation value is a display RGB color gradation value defined in the index table IDT. That is, the color sample CS indicates the color of the paint corresponding to each index IDX. A character indicating the index IDX or a character indicating the name of the paint may be displayed near the color sample CS. Since many color samples CS of the paint cannot be displayed at a time in a limited area of the special color palette PL, a slider may be provided. Further, the color samples CS to be displayed may be narrowed down based on the hue and brightness indicated by the display RGB color gradation values. The UI part P1a of the image editing program P1 accepts a click on the color sample CS (step S174). The monitoring unit P2a of the plug-in module P2 detects the click, and uses the index IDX associated with the display RGB color gradation value of the clicked color sample CS in the index table IDT as the main image editing instruction unit P2c. The layer editing instruction unit P2d acquires (step S175). The color displayed on the display 16a based on the display RGB color gradation value of the clicked color sample CS corresponds to the designated color of the present invention. Next, the determination unit P2f refers to the format flag FL on the RAM 12 to determine the classifications A to C of the image editing program P1 (step S176). Up to this point, the processing is common to the classifications A to C. Hereinafter, the spot color editing processes of the classifications A to C will be described in order.

2-2-1. Special color editing for category A:
When the index IDX corresponding to the specified color can be acquired, the main image editing instruction unit P2c of the plug-in module P2 sends an editing instruction for the main image data MID developed in the RAM 12 to the main image editing unit P1c of the image editing program P1. (Step S177A). The main image editing instruction unit P2c instructs the X gradation value of the pixels belonging to the designated area in the main image data MID to be 1. That is, an instruction is given to give an X gradation value indicating that a pixel belonging to the designated area is a spot color area. Further, an instruction is given to replace the RGB gradation value of the pixel belonging to the designated area in the main image data MID with the RGB gradation value indicating the index IDX corresponding to the designated color. That is, it instructs the pixel belonging to the designated area to store the index IDX instead of the RGB color gradation value. For the spot color pixel that originally stores the index IDX by the RGB gradation value, an instruction is given to rewrite the index IDX corresponding to the newly designated color. In response to the above editing instruction, the main image editing unit P1c edits the main image data MID (step S178). In the case of classification A, the main image editing unit P1c of the image editing program P1 can edit not only the RGB gradation values but also the X gradation values, so that the X gradations according to the editing instruction of the main image editing instruction unit P2c. You can edit the value.

  Next, the UI instruction unit P2b edits the display image data DID (step S181A. Here, the UI instruction unit P2b uses the display RGB color gradation value indicating the specified color to display each spot color belonging to the specified area. Replace the RGB gradation values of the pixels, that is, edit the designated spot color area into display image data DID filled with the same color as the color sample CS designated in the spot color palette PL. If possible, a display instruction is output to the UI part P1b to display the display image data DID in the preview area W1 (step S182A) In response to the display instruction, the UI part P1b displays the image in the preview area W1. (Step S183) As shown in the UI image of Fig. 12, the designated area is the designated color sample CS. Can be contrasted. The color of the spot color area to be the uniform indicating a color, a furniture and photographic images walls of the room has been photographed.

2-2-2. Special color editing for category B:
Also in the case of classification B, the main image editing instruction unit P2c of the plug-in module P2 outputs an editing instruction for the main image data MID developed in the RAM 12 to the main image editing unit P1c of the image editing program P1 ( Step S177BC). Here, an editing instruction having different contents from that of the classification A is output. The main image editing instruction unit P2c instructs to replace the RGB color gradation values of the pixels belonging to the designated area in the main image data MID with the display RGB color gradation values corresponding to the designated color. That is, the designated spot color area is instructed to be edited into main image data MID filled with the same color as the color sample CS designated in the spot color palette PL. The special color pixel that originally stored the display RGB color gradation value is instructed to be rewritten to the display RGB color gradation value corresponding to the newly specified color. In response to the above editing instruction, the main image editing unit P1c edits the main image data MID (step S178). In the case of classification B, the main image editing unit P1c of the image editing program P1 can edit the RGB gradation values, so that the RGB gradation values can be edited according to the editing instruction of the main image editing instruction unit P2c. . When the RGB gradation value of each pixel of the main image data MID is converted into another color system such as CMYK gradation value and expanded in the RAM 12, the display RGB color gradation value is displayed. Are converted into CMYK gradation values and the like, and then the CMYK gradation values are replaced.

  Next, the layer editing instruction unit P2d of the plug-in module P2 outputs an editing instruction for the layer image data AID developed in the RAM 12 to the layer editing unit P1d of the image editing program P1 (step S179B). If a spot color pixel exists in classification B, a single layer image data AID is created by the file development process, and a tone value indicating the index IDX is stored in the spot color pixel in the layer image data AID. Yes. The layer editing instruction unit P2d instructs to replace the gradation value of the pixel in the designated area with the gradation value indicating the index IDX corresponding to the designated color in the layer image data AID. When the normal pixel belongs to the newly designated spot color area, the gradation value of the pixel is instructed to be replaced with the gradation value indicating the index IDX from the gradation value 0 indicating the normal pixel. Become. On the other hand, if the pixel is originally a spot color pixel, an instruction is given to replace the tone value of the spot color pixel with the tone value indicating the new index IDX from the original index IDX.

  By the way, in the file development process, when there is no spot color pixel, the layer image data AID is not created in advance. In this case, after an instruction to newly create layer image data AID is output to the layer editing unit P1d, the gradation value of the pixel in the designated area is replaced with the gradation value indicating the index IDX corresponding to the designated color. Instruct them to do so. In response to the above editing instruction, the layer editing unit P1d edits the layer image data AID (step S180). In the case of the classification B, the layer editing unit P1d can edit the 24-bit index IDX in the layer, so that the layer (layer image data AID) can be edited according to the editing instruction of the layer editing unit P1d.

  Next, the UI instruction unit P2b outputs a display instruction to the UI unit P1b so that the edited main image data MID is displayed as it is in the preview area W1 (step S182BC). The RGB gradation value (display RGB color gradation value) of each pixel (special color pixel and normal pixel) of the main image data MID is a color gradation value indicating a color, and therefore can be displayed without any problem. (Step S183). As in the case of the classification A, the designated area uniformly indicates the color of the designated color sample CS, and the color of the special color area can be compared with the photographic image in which the wall of the furniture or the room is copied. it can.

2-2-3. Special color editing for category C:
Also in the case of category C, the main image editing instruction unit P2c of the plug-in module P2 outputs an editing instruction for the main image data MID developed in the RAM 12 to the main image editing unit P1c of the image editing program P1 ( Step S177BC). The content of the editing instruction for the main image data MID is the same as in the case of classification B. In response to the editing instruction, the main image editing unit P1c edits the main image data MID (step S178). Next, the layer editing instruction unit P2d of the plug-in module P2 outputs an editing instruction for the layer image data AID developed in the RAM 12 to the layer editing unit P1d of the image editing program P1 (step S179C). When there are special color pixels in the classification C, the number of layer image data AID corresponding to the number of different index IDX is created by the file expansion process, and the special color pixels in each layer image data AID are special color pixels. A tone value of 1 is stored. Further, the name of the layer of each layer image data AID is an index IDX corresponding to each layer image data AID. If no special color pixel exists, no layer image data AID is created in the file development process.

  The layer editing instruction unit P2d determines whether or not a layer having the same name as the index IDX corresponding to the designated color has already been created. If the layer has not already been created, the layer image data AID as a new layer is determined. Instruct the creation of. Then, an instruction is given to give a gradation value of 1 indicating that the pixel belonging to the specified area in the newly created layer image data AID is a spot color pixel. On the other hand, when a layer having the same name as the index IDX corresponding to the designated color has already been created, the gradation value 1 indicating that the pixel belonging to the designated area in the layer image data AID of the layer is a spot color pixel Is instructed to be granted. In response to the above editing instruction, the layer editing unit P1d edits the layer image data AID (step S180).

  Next, the UI instruction unit P2b instructs the UI unit P1b to display the edited main image data MID as it is in the preview area W1 (step S181C). The RGB gradation value (display RGB color gradation value) of each pixel (special color pixel and normal pixel) of the main image data MID is a color gradation value indicating a color, and therefore can be displayed without any problem. (Step S182C). As in the case of the classification A, the designated area uniformly indicates the color of the designated color sample CS, and the color of the special color area can be compared with the photographic image in which the wall of the furniture or the room is copied. it can.

2-3. File output processing:
By the special color editing process described above, an image based on the display image data DID (class A) or the main image data MID (class B, C) is displayed in the UI image preview area W1 shown in FIG. Filled spot color areas are provided. In the image processing of FIG. 3, a click on the file save button B4 and the print execution button B5 is detected (step S135), and when a click on either is detected, the file output process (step S190-) is executed.

  FIG. 13 is a flowchart showing the flow of the file output process (step S190 to S190). First, the determination unit P2f refers to the format flag FL on the RAM 12 to determine the classifications A to C of the image editing program P1 (step S191). Hereinafter, the file output processing of the classifications A to C will be described in order.

2-3-1. File output for category A:
In the case of the classification A, main image data MID in which each pixel has RGBX gradation values is developed on the RAM 12 as first image data FID. The format converter P2e uses the main image data MID as it is as the second image data SID without converting the format (step S192A). The format conversion unit P2e transfers the second image data SID to the file output unit P1e (step S194). When the file save button B4 is clicked (step S195), the file output unit P1e stores the second image data SID in the HDD 14 (step S196). On the other hand, when the print execution button B5 is clicked (step S195), the file output unit P1e causes the printer driver P3 to output the second image data SID (step S197).

2-3-2. File output for category B:
In the case of the classification B, first, a spot color pixel in which the index IDX (any gradation value other than 0) is stored in the layer image data AID developed on the RAM 12 is specified, and the index IDX is used in the main image data MID. Stored as the RGB gradation value of the corresponding pixel (step S192B). Since the special color pixel of the main image data MID stores the display RGB color gradation value, the display RGB color gradation value is replaced with the index IDX. Next, an X channel is added to the main image data MID, the X gradation value of the special color pixel specified based on the layer image data AID is set to 1, and the X gradation value is set to 0 for the other normal pixels. (Step S193BC). That is, a flag indicating that the pixel is a spot color pixel is assigned with an X gradation value of 1. As described above, each pixel is converted into the second image data SID having RGBX gradation values. When the conversion to the second image data SID is completed, the same processing as in the case of classification A is performed thereafter (steps S194 to S197).

2-3-3. File output for category C:
In the case of classification C, first, a spot color pixel having a gradation value of 1 in each layer image data AID developed on the RAM 12 is specified, and the index IDX indicated by the name of each layer image data AID is used as the main image data. Stored as the RGB gradation value of the corresponding pixel in the MID (step S192C). Since the special color pixel of the main image data MID stores the display RGB color gradation value, the display RGB color gradation value is replaced with the index IDX. Next, an X channel is added to the main image data MID, the X gradation value of the special color pixel specified based on the layer image data AID is set to 1, and the X gradation value is set to 0 for the other normal pixels. (Step S193BC). As described above, each pixel is converted into the second image data SID having RGBX gradation values. When the conversion to the second image data SID is completed, the same processing as in the case of classification A is performed thereafter (steps S194 to S197).

  As described above, in any of the classifications A to C, each pixel is finally converted into the second image data SID having RGBX gradation values. When the second image data SID is edited again, the second image data SID is converted into the first image data FID by the file development process described above, and can be edited by each image editing program P1 (AP1 to AP3). Further, in any of the above-described file development processing, spot color editing processing, and file output processing, the processing contents of the image editing program P1 in the classifications A to C are the same, and processing depending on the classifications A to C is a plug-in. Provided by module P2. Therefore, if the image editing program P1 can handle the image data of the classifications A to C, special color editing can be performed. Therefore, it is possible to select the image editing program P1 that the user is familiar with. In the present embodiment, the existing second image data SID is expanded and edited. However, an image may be created from a blank canvas by spot color editing processing. Also in this case, the first image data FID created by the spot color editing process is converted into the second image data SID and output.

3. Print control processing:
FIG. 14 is a flowchart showing the flow of the print control process. The printer driver P3 that has received the output of the second image data SID starts color conversion processing by the color conversion unit P3a. In the color conversion process, one pixel is selected from the second image data SID in which each pixel has RGBX gradation values (step S200), and it is determined whether or not the X gradation value of the pixel is 1. (Step S220). That is, it is determined whether or not the selected pixel is a spot color pixel. If the pixel is a spot color pixel, the index table IDT is acquired from the HDD 14, and the index IDX stored as the RGB gradation value is referred to the index table IDT to the ink amount set φ corresponding to the index IDX. Conversion is performed (step S230). On the other hand, if the pixel is a normal pixel, the color conversion table LUT is acquired from the HDD 14, and the color conversion table LUT is referred to the CMYKlclm ink amount set φ corresponding to the RGB color gradation value stored in the pixel. (Step S240). The color conversion unit P3a that acquires the index table IDT and the color conversion table LUT from the HDD 14 constitutes a profile acquisition unit of the present invention. In the color conversion table LUT, an ink amount set φ is associated with grid points that are uniformly distributed in the RGB space, and each normal pixel is obtained by performing an interpolation operation using the ink amount set φ for the grid points. An ink amount set φ corresponding to the RGB color gradation values is calculated. Note that the color conversion table LUT is a look-up table that is referred to when the printer 20 prints a normal printed matter. For example, it is created by the technique of 2007-336198 gazette. According to this method, it is possible to create a color conversion table LUT in which the gradation of reproduced colors, graininess, light source independence of reproduced colors, gamut, and ink duty are generally good.

  The color conversion unit P3a determines whether or not the conversion to the ink amount set φ has been completed for all the pixels (step S250). If the conversion has not been completed, the same processing is performed for the next pixel. When the color conversion process is completed, ink amount image data in which all pixels store the ink amount set φ of CMYKlclm can be generated. The halftone portion P3b acquires the ink amount image data after color conversion, and executes halftone processing on the ink amount image data (step S260). When the halftone process is completed, the print data generation unit P3c generates print data to be output to the printer 20 based on the halftone data after the halftone process (step S270). Specifically, each pixel of the halftone data is assigned to each nozzle of the print head included in the printer 20, or each pixel of the halftone data is rearranged in the scanning order of the print head. Finally, by outputting the print data to the printer 20, the printer 20 forms a print image corresponding to the second image data SID on the printing paper.

  By doing as described above, the existing spot color pixels and the spot color pixels added in the spot color editing process are printed based on the CMYKlclm ink amount set φ defined in the index table IDT. Therefore, the same spectral reflectance as that of the corresponding paint can be reproduced in the printed matter.

4). About index tables:
4-1. About creating an index table:
FIG. 15 shows a software configuration of the computer 10 that executes the index table creation process. The index table IDT may be created by the computer 10 or may be created by another computer. The computer 10 executes an index table creation program P4 as a software configuration for performing index table creation processing. The index table creation program P4 includes a target measurement unit P4a, an ink amount set calculation unit P4b, a spectral prediction unit P4c, a display RGB color gradation value calculation unit P4d, and a table creation unit P4e. The target measurement unit P4a uses the spectral reflectometer 30 to measure the spectral reflectance of the sample actually coated with each paint as the target spectral reflectance R _t (λ). The sample here is, for example, a piece of wood, a piece of plastic or a piece of stone coated with each paint. The ink amount set calculation unit P4b calculates an ink amount set that can reproduce the target spectral reflectance R _t (λ) using a spectral printing model described later. The table creation unit P4e creates an index table IDT that defines the correspondence relationship between the ink amount set φ calculated by the ink amount set calculation unit P4b and the index IDX.

FIG. 16 shows the flow of index table creation processing. In step S510, the target measurement unit P4a selects a target paint, and generates a unique index IDX (serial number from 1 in this embodiment) for the paint. For example, one paint is selected from thousands of kinds of paint handled by a paint manufacturer. In step S520, the target spectral reflectance R _t (λ) of the selected paint sample is measured by the spectral reflectometer 30. The target spectral reflectance R _t (λ) is a vector composed of the spectral reflectance R (λ) in each wavelength section (for example, 10 nm section). In step S530, the ink amount set determining unit P4b calculates the optimal solution of the target spectral reflectances R _t that are reproducible ink amount set by using the spectral prediction unit P4c. Hereinafter, an arbitrary ink amount set of _CMYKlclm is expressed as a vector φ = (d _C , d _M , d _Y , d _K , d _lc , d _lm ). The spectral prediction unit P4c inputs an arbitrary ink amount set φ, and the spectral reflectance when the printer 20 prints on glossy paper with the ink amount set φ (hereinafter, predicted spectral reflectance R _s (λ )).) That is, as shown in the following equation (1), the spectral prediction unit P4c provides a function PM (φ) for inputting the ink amount set φ and calculating the predicted spectral reflectance R _s (λ).

The ink amount set calculation unit P4b calculates a difference D (λ) between the target spectral reflectance R _t (λ) and the predicted spectral reflectance R _s (λ) for each wavelength λ, and a weight is assigned to each wavelength λ. The difference function D (λ) is multiplied by the weight function w (λ). The square root of the mean square of this value is calculated as the evaluation value E (φ). The above calculation can be expressed by the following equation (2).

In the above equation (2), N means the number of divisions of the wavelength λ. In the above equation (2), the smaller the evaluation value E (φ), the smaller the difference between the target spectral reflectance R _t (λ) and the predicted spectral reflectance R _s (λ) at each wavelength λ. it can. That is, the smaller the evaluation value E (φ), the more the spectral reflectance R (λ) reproduced on the glossy paper when the printer 18b is printed with the input ink amount set φ and the corresponding paint sample. It can be said that the obtained target spectral reflectance R _t (λ) is approximate.

  Furthermore, the reproduction color of the printer 20 based on the ink amount set φ and the absolute color indicated by the corresponding paint sample vary depending on the variation of the light source, but the evaluation value E (φ) is reduced. Thus, the colors of both can be relatively matched. Therefore, according to the ink amount set φ in which the evaluation value (φ) is small, it can be said that it is possible to obtain a printing result that is perceived to be equivalent to the color indicated by the paint in any light source.

前記の（３）式においては、等色関数ｘ（λ），ｙ（λ），ｚ（λ）を加算することにより、重み関数ｗ（λ）が定義されている。なお、前記の（３）式の右辺全体に所定の係数を乗算して、重み関数ｗ（λ）の値の範囲を正規化してもよい。等色関数ｘ（λ），ｙ（λ），ｚ（λ）は、人間の視覚感度（３刺激値）に応じたスペクトルを有しており、人間の視覚感度が敏感な波長域での分光反射率Ｒ（λ）を重視させることができる。例えば、人間の目に知覚されない近紫外波長域においてはｗ（λ）が０となり、当該波長域における差分Ｄ（λ）は評価値Ｅ（φ）の増大に寄与しないこととなる。 In this embodiment, the weighting function w (λ) uses the following equation (3).

In the above equation (3), the weighting function w (λ) is defined by adding the color matching functions x (λ), y (λ), and z (λ). The range of the value of the weighting function w (λ) may be normalized by multiplying the entire right side of the equation (3) by a predetermined coefficient. The color matching functions x (λ), y (λ), and z (λ) have a spectrum corresponding to human visual sensitivity (tristimulus values), and are spectral in a wavelength region where human visual sensitivity is sensitive. The reflectance R (λ) can be emphasized. For example, w (λ) is 0 in the near ultraviolet wavelength region that is not perceived by human eyes, and the difference D (λ) in the wavelength region does not contribute to the increase in the evaluation value E (φ).

That is, even if the difference between the target spectral reflectance R _t (λ) and the predicted spectral reflectance R _s (λ) is not necessarily small in the entire visible wavelength range, If the reflectance R _t (λ) is similar to the predicted spectral reflectance R _s (λ), a small evaluation value E (φ) can be obtained, and the spectral reflectance suitable for human perception. The evaluation value E (φ) can be used as an index of the closeness of R (λ). The ink amount set calculation unit P4b causes the spectral prediction unit P4c to calculate the predicted spectral reflectance R _s (λ) each time while sequentially shifting the ink amount set φ, and calculates the evaluation value E (φ). Then, the optimum solution of the ink amount set φ that minimizes the evaluation value E (φ) is calculated. As a method for calculating the optimum solution, various optimization methods can be used. For example, it is desirable to use a nonlinear optimization method such as a gradient method.

As described above, when the ink amount set φ capable of reproducing the target spectral reflectance R _t (λ) can be calculated in step S530, the table creating unit P4e measures the target spectral reflectance R _t (λ). The sample index IDX, the target spectral reflectance R _t (λ), and the calculated ink amount set φ are stored in the index table IDT in association with each other (step S540). Next, it is assumed that the display RGB color gradation value calculation unit P4d irradiates an object having a target spectral reflectance R _t (λ) with a standard light source (CIE-D65 standard light source in this embodiment). Then, an RGB color gradation value in the sRGB color space indicating the color of the object at that time is calculated (step S550). Specifically, first, an XYZ value that an object having an arbitrary target spectral reflectance R _t (λ) is shown under a CIE-D65 standard light source is calculated by the following equation (4).

  In the above equation (4), P (λ) represents the spectral energy of the CIE-D65 standard light source, and k represents a coefficient for normalization. Since the spectral energy P (λ) of the D65 light source is standardized and known, it can be stored in the HDD 14 in advance and can be read and used by the paint specifying module M1c. Next, the XYZ values are converted into RGB gradation values in the sRGB color space using a color space profile that defines the correspondence between the XYZ color space and the sRGB color space. Since both the XYZ color space and the sRGB color space are known device-independent color spaces, a color space profile that defines the correspondence between these can be prepared in the HDD 14.

The table creating unit P4e stores the calculated RGB gradation values in the index table IDT as display RGB color gradation values in association with the index IDX (step S560). It is determined whether or not all the paints have been selected (step S570). If not, the process returns to step S510 to select the next paint. Accordingly, the paints can be sequentially selected, and the ink amount set φ and the display RGB color gradation values that can reproduce the target spectral reflectance R _t (λ) are calculated for each paint, and the index of each paint is calculated. It is possible to create an index table IDT that stores the correspondence between IDX, ink amount set φ, and display RGB color gradation values.

5. Spectral Printing Model FIG. 17 schematically shows a printing method of the printer 20 of this embodiment. The printer 20 includes a print head 21 having a plurality of nozzles 21a, 21a,... For each CMYKlclm ink, and the ink amount for each CMYKlclm ink ejected by the nozzles 21a, 21a,. the amount set _{φ (d c, d m,} d y, d k, d lc, d lm) is controlled to an amount specified by performed based on the print data PD. Each nozzle 21a, the ink droplets 21a · · · is discharged becomes fine dots on the printing paper, a number of dots of ink amount set by a collection _{φ (d c, d m,} d y, d k, d lc, d A print image having an ink coverage corresponding to _lm ) is formed on the printing paper.

Predictive model spectral prediction unit P4c can be used (spectral printing model), any ink amount set phi (d _c that may be used in the printer 20 of this _{embodiment, d m, d y, d} k, d lc, d lm ) Is a prediction model for predicting the spectral reflectance R (λ) when printing is performed as the predicted spectral reflectance R _s (λ), and corresponds to the function PM (φ) of the above equation (1). . In the spectral printing model, color patches are actually printed at a plurality of representative points in the ink amount space by a standard machine (printer 20), and the spectral reflectance R (λ) is measured by a spectral reflectance meter. A spectral reflectance database RDB is prepared. An arbitrary ink amount set φ (d _c , d) is accurately obtained by performing prediction using the Cellular Yule-Nielsen Spectral Neugebauer Model using the spectral reflectance database RDB. _m , d _y , d _k , d _lc , d _lm ), and the spectral reflectance R (λ) when printing is predicted.

FIG. 18 shows the spectral reflectance database RDB. As shown in the figure, the spectral reflectance database RDB is an ink amount set φ (d) of a plurality of lattice points in the ink amount space (in this embodiment, it is 6-dimensional, but only the CM plane is shown for simplification of the drawing). _c , d _m , d _y , d _k , d _lc , d _lm ) are look-up tables in which spectral reflectances R (λ) obtained by actually printing / measuring are described. For example, five grid points that divide each ink amount axis are generated. Here 5 ¹³ also lattice points are generated, it is necessary to print / measurement of color patches of huge amount, actually can be discharged simultaneously mountable ink number and simultaneously with the printer 20 ink Since the duty is limited, the number of grid points to be printed / measured is reduced.

  Further, only some of the lattice points are actually printed / measured, and the other lattice points are spectrally reflected R (λ) based on the spectral reflectance R (λ) of the actually printed / measured lattice points. Thus, the number of color patches that are actually printed / measured may be reduced. The spectral reflectance database RDB needs to be prepared for each printing paper that can be printed by the printer 20. Strictly speaking, the spectral reflectance R (λ) is determined by the spectral transmittance of the ink film (dot) formed on the printing paper and the reflectance of the printing paper, and the surface physical properties of the printing paper (depending on the dot shape). ) And reflectivity. Next, prediction by the cell division Yule-Nielsen spectral Neugebauer model using the spectral reflectance database RDB will be described.

  The spectral prediction unit P4c executes prediction based on the cell division Yule-Nielsen spectral Neugebauer model using the spectral reflectance database RDB. For this prediction, printing paper (glossy paper in this embodiment) and ink amount set φ are set as printing conditions. When prediction is performed using glossy paper as printing paper, a spectral reflectance database RDB created by printing color patches on glossy paper is set.

When it is set in the spectral reflectance database RDB, the ink amount set which is output from the ink amount set calculation unit P4b and correction amount calculating module _{M16 φ (d c, d m} , d y, d k, d lc, d lm) To the spectral printing model. The cell splitting Yule-Nielsen spectroscopic Neugebauer model is based on the well-known spectroscopic Neugebauer model and the Yule-Nielsen model. In the following description, for simplification of description, a model in the case of using three types of CMY inks will be described. However, a similar model is used as a model using an arbitrary ink set including CMYKlclm of the present embodiment. It is easy to expand. For the cell division Yule-Nielsen spectral Neugebauer model, see Color Res Appl 25, 4-19, 2000 and R Balasubramanian, Optimization of the spectral Neugebauer model for printer characterization, J. Electronic Imaging 8 (2), 156- See 166 (1999).

FIG. 19 is a diagram showing a spectral Neugebauer model. The spectral Neugebauer model, optional ink amount sets _{(d c, d m, d} y) predicted spectral reflectance of the printed matter when printed with R _s (lambda) is given by the following equation (5).

Here, a _i is the area ratio of the i-th region, and R _i (λ) is the spectral reflectance of the i-th region. The subscript i includes an area without ink (w), an area only with cyan ink (c), an area only with magenta ink (m), an area only with yellow ink (y), magenta ink and yellow ink. A region (r) where yellow ink and cyan ink are ejected, a region (b) where cyan ink and magenta ink are ejected, and a region where three inks CMY are ejected (region) (r) k) respectively. Further, f _c , f _m , and _fy are the proportions of the area covered with only one CMY ink when it is ejected (referred to as “Ink area coverage”).

The ink coverages f _c , f _m , and _fy are given by the Murray-Davis model shown in FIG. 19B. In the Murray-Davies model, for example, the ink area coverage f _c of the cyan ink is a nonlinear function of the ink amount d _c of the cyan, be converted to the ink amount d _c in the ink coverage f _c, for example by one-dimensional lookup table Can do. Ink coverage f _c, f _m, f _y is the ink amount d _c, d _m, reason for the non-linear function of d _y is spread enough ink in the case where a small amount of ink ejected to the unit area, This is because, when a large amount of ink is ejected, the ink is overlapped and the area covered with the ink does not increase so much. The same applies to other types of MY inks.

ここで、ｎは１以上の所定の係数であり、例えばｎ＝１０に設定することができる。前記の（６ａ）式および（６ｂ）式は、ユール・ニールセン分光ノイゲバウアモデル(Yule-Nielsen Spectral Neugebauer Model)を表す式である。 When the Yule-Nielsen model for spectral reflectance is applied, the equation (5) can be rewritten as the following equation (6a) or (6b).

Here, n is a predetermined coefficient of 1 or more, and can be set to n = 10, for example. The above equations (6a) and (6b) are equations representing the Yule-Nielsen Spectral Neugebauer Model.

  The Cellular Yule-Nielsen Spectral Neugebauer Model adopted in this example is a system in which the ink amount space of the above-mentioned Yule-Nielsen Spectral Neugebauer Model is divided into a plurality of cells. is there.

FIG. 20A shows an example of cell division in the cell division Yule-Nielsen spectroscopic Neugebauer model. Here, for simplification of description depicts the cell division in a two-dimensional ink amount space including two axes of the ink amount d _c, d _m of the CM inks. Note that it for ink coverage f _c, is f _m with at Murray-Davis model described above the ink amount d _c, a unique relationship with d _m, the ink coverage f _c, also be considered as an axis indicating the f _m . White circles are cell division grid points (called “lattice points”), and a two-dimensional ink amount (coverage) space is divided into nine cells C1 to C9. The ink amount set (d _c , d _m ) corresponding to each lattice point is an ink amount set corresponding to the lattice point defined in the spectral reflectance database RDB. That is, the spectral reflectance R (λ) of each lattice point can be obtained by referring to the above-described spectral reflectance database RDB. Therefore, the spectral reflectances R (λ) ₀₀ , R (λ) ₁₀ , R (λ) ₂₀ ... R (λ) ₃₃ of each lattice point can be acquired from the spectral reflectance database RDB.

In fact, performs also the cell division in a six-dimensional ink amount space of CMYKlclm In this embodiment, the ink amount set phi (d _c of six-dimensional coordinates of each grid _{point, d m, d y, d} k, d lc , D _lm ). Then, the ink amount set φ for each grid point _{(d c, d m, d} y, d k, d lc, d lm) spectral reflectivity of the grid points corresponding to R (lambda) is the spectral reflectance database RDB (for example, (From glossy paper).

Figure 20B shows the relationship between the ink area coverage f _c and the ink amount d _c which are used in the cell division model. Here, one kind of the ink amount in the range 0 to D _cmax of ink is also divided into three sections, the virtual used in the cell division model by non-linear curve which increases monotonically from 0 for each section to the 1 A typical ink coverage _fc is determined. For other inks, the ink coverages f _m and f _y are obtained in the same manner.

ここで、（７）式におけるインク被覆率ｆ_c，ｆ_mは図２０Ｂのグラフで与えられる値である。また、セルＣ５を囲む４つの格子点に対応する分光反射率Ｒ（λ）₁₁，（λ）₁₂，（λ）₂₁，（λ）₂₂は分光反射率データベースＲＤＢを参照することにより取得することができる。これにより、（７）式の右辺を構成するすべての値を確定することができ、その計算結果として任意のインク量セットφ（ｄ_c，ｄ_m）にて印刷を行った場合の予測分光反射率Ｒ_s（λ）を算出することができる。波長λを可視波長域にて順次シフトさせていくことにより、可視波長域における予測分光反射率Ｒ_s（λ）を得ることができる。インク量空間を複数のセルに分割すれば、分割しない場合に比べて予測分光反射率Ｒ_s（λ）をより精度良く算出することができる。以上のようにして、分光予測部Ｐ４ｃがインク量セット算出部Ｐ４ｂや補正量算出モジュールＭ１６の要請に応じて予測分光反射率Ｒ_s（λ）を予測することができる。 FIG. 20C shows a method of calculating the predicted spectral reflectance R _s (λ) when printing is performed with an arbitrary ink amount set (d _c , d _m ) in the center cell C5 of FIG. 20A. . The spectral reflectance R (λ) when printing is performed with the ink amount set (d _c , d _m ) is given by the following equation (7).

Here, the ink coverages f _c and f _m in the equation (7) are values given by the graph of FIG. 20B. The spectral reflectances R (λ) ₁₁ , (λ) ₁₂ , (λ) ₂₁ , and (λ) ₂₂ corresponding to the four lattice points surrounding the cell C5 are acquired by referring to the spectral reflectance database RDB. Can do. Thereby, all values constituting the right side of the equation (7) can be determined, and the predicted spectral reflection when printing is performed with an arbitrary ink amount set φ (d _c , d _m ) as the calculation result. The rate R _s (λ) can be calculated. By sequentially shifting the wavelength λ in the visible wavelength region, the predicted spectral reflectance R _s (λ) in the visible wavelength region can be obtained. If the ink amount space is divided into a plurality of cells, the predicted spectral reflectance R _s (λ) can be calculated more accurately than when the ink amount space is not divided. As described above, the spectral prediction unit P4c can predict the predicted spectral reflectance R _s (λ) in response to a request from the ink amount set calculation unit P4b and the correction amount calculation module M16.

6). Variation:
FIG. 21 is a flowchart showing the flow of the spot color editing process (from step S170) according to the modification. Until step S171, the same processing as in the previous embodiment is executed. The UI unit P1a receives an input of a designated light source in the UI image (step S1711), and the UI instruction unit P2b acquires the accepted designated light source (step S1712). Although not shown, a radio button or the like for selectively selecting a D50 light source, an F11 light source, an A light source, or the like is provided in the UI image. Next, the UI instruction unit P2b refers to the index table IDT to acquire the display RGB color gradation value with the designated light source corresponding to the index IDX, and uses each display color palette according to the display RGB color gradation value. Is instructed to display the color sample CS (step S1721). In the present embodiment, display RGB color gradation values that differ for each light source are stored in the index table IDT.

  FIG. 22 is a diagram showing an index table IDT according to this modification. In the index table IDT, the display RGB color gradation value is stored for each light source for each index IDX, and the display RGB color gradation value for the light source designated as the designated light source is acquired. The RGB color gradation values for display are obtained by converting the XYZ values obtained by substituting the spectral energy P (λ) of each light source into the equation (4) to RGB color gradations in the sRGB color space. Value. Of course, the RGB color gradation value for display may be obtained by measuring the color of the paint sample corresponding to each index IDX when the light source is actually irradiated with a colorimeter. Further, the display RGB color gradation values for the light sources of the respective light sources do not need to be stored in the index table IDT in advance, and the spectral energy P (λ) of the designated light source is determined at the stage where the designated light source is designated. It may be calculated by substituting into the equation (4). The subsequent processing is the same as in the previous embodiment. Accordingly, the color displayed on the color sample CS in the special color palette is the color indicated by the paint corresponding to each index IDX in the designated light source. Therefore, the user can confirm the performance when the paint is actually applied by checking the print result by designating the designated light source corresponding to the light source where the paint is actually applied.

The date and time when calibration was last performed is recorded in the index table IDT. Calibration is a process for adjusting the ink amount set φ recorded in the index table IDT. Specifically, the ink amount set φ is set so that the spectral reflectance measurement result of the color patch printed based on the ink amount set φ recorded in the index table IDT approaches the target spectral reflectance R _t (λ). It is a process to adjust. Since changes over time such as the amount of ink ejected from the print head 21 are unavoidable, it is desirable to perform calibration periodically. It is considered that the closer the calibration date and time is to the present, the more accurately the spectral reflectance when printing based on the ink amount set φ recorded in the index table IDT reproduces the target spectral reflectance R _t (λ). be able to. Therefore, if the difference between the date and time of printing (current) and the date and time of last calibration is equal to or greater than a predetermined threshold (for example, three months), a warning display that prompts calibration is displayed in the print control process. You may do it. Of course, when the second image data SID does not include a special color pixel (when the X gradation values are all 0), it is not necessary to consider the accuracy of the index table IDT. It is desirable not to issue a warning even if

  Further, the technical idea of the present invention can be embodied not only by specific hardware but also by a method performed by the system. That is, the present invention can also be specified as a method having steps corresponding to each means performed by the system described above. Of course, when the above-described system reads a program to realize each of the above-described means, the technical idea of the present invention can be applied to a program for executing a function corresponding to each of the means and various recording media on which the program is recorded. Needless to say, it can be realized.

  10 ... Computer, 11 ... CPU, 12 ... RAM, 13 ... ROM, 14 ... HDD, 16 ... Video I / F, 17 ... Input device I / F, 18 ... General-purpose I / F, 19 ... Bus, 16a ... Display, 17a ... Keyboard, 17b ... Mouse, P1 ... Image editing program, P1a ... UI part, P1b ... File development part, P1c ... Main image editing part, P1d ... Layer editing part, P1e ... File output part, P2 ... Plug-in module, P2a ... monitoring unit, P2b ... UI instruction unit, P2c ... main image editing instruction unit, P2d ... layer editing instruction unit, P2e ... format conversion unit, P2f ... determination unit.

Claims (8)

Image editing means for editing first image data comprising main image data having pixels for storing color gradation values indicating colors and layer image data in which pixels are arranged in the same manner as the image data;
Image editing instruction means for instructing the image editing means to store information indicating whether or not each pixel of the main image data is a spot color pixel in each pixel of the layer image data;
Identifying the spot color pixel in the main image data based on the layer image data;
About the specified spot color pixel,
Conversion means for storing an index associated with an amount of ink to be used by a printing apparatus instead of the color gradation value, and generating second image data in which a flag indicating the special color pixel is stored An image processing apparatus comprising: Profile acquisition means for acquiring a first conversion profile that defines the correspondence between the index and the ink amount, and a second conversion profile that defines the correspondence between the color gradation value and the ink amount;
In the second image data, for the pixel in which the index is stored, the index is converted into the ink amount by referring to the first conversion profile, and for the pixel in which the index is not stored, the pixel is stored. A color conversion unit that generates ink amount image data in which each pixel stores the ink amount by converting the color gradation value into the ink amount by referring to a second conversion profile. Item 8. The image processing apparatus according to Item 1.   The image processing apparatus according to claim 1, wherein the image editing instruction unit instructs the image editing unit to store the index as a name of the layer image data.   The image processing apparatus according to claim 1, wherein the image editing instruction unit instructs the image editing unit to store the index as a gradation value of each pixel in the layer image data.   The image editing instruction unit receives designation of a color sample displayed on the display device, and assigns the index corresponding to the designated color indicated by the designated color sample to each name in the layer image data or each layer image data The image processing apparatus according to claim 4, wherein the image processing apparatus stores the gradation value of a pixel.   The image editing instruction means receives a designated light source together with the color sample, and uses the index corresponding to the ink amount for reproducing the designated color under the designated light source as the name of the layer image data or the layer image data. The image processing apparatus according to claim 5, wherein the image processing apparatus stores the gradation value of each pixel in the pixel. The image editing means is provided in a computer that executes an image editing program,
The image processing apparatus according to claim 1, wherein the image editing instruction unit and the conversion unit are provided in a computer that executes a plug-in module incorporated in the image editing program. The image editing means edits first image data including main image data having pixels for storing color gradation values indicating colors and layer image data in which pixels are arranged in the same manner as the image data,
The image editing instruction means instructs the image editing means to store information indicating whether each pixel of the main image data is a spot color pixel in each pixel of the layer image data,
Identifying the spot color pixel in the main image data based on the layer image data;
About the specified spot color pixel,
An image processing method for generating second image data in which an index associated with an ink amount to be used by a printing apparatus is stored instead of the color gradation value, and a flag indicating that the pixel is a spot color pixel is stored .

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