JP4685687B2 - Parameter providing apparatus, color conversion system, parameter providing program, and color conversion program - Google Patents

Description

  The present invention provides a parameter providing apparatus that provides a color conversion apparatus with parameters that define coordinate conversion between different color spaces, a parameter providing program, and a parameter provided, and uses the parameters to convert input image data. The present invention relates to a color conversion system for converting output image data and a color conversion program.

  2. Description of the Related Art Conventionally, an image input / output system is known that reads an original image with an image input device to acquire image data, and outputs an image based on the image data with an image output device.

  Generally, an image input device reads an image for each color component of R (red), G (green), and B (blue) by irradiating the image with light. Then, input image data in the RGB color space is obtained. On the other hand, many image output apparatuses form an image using color materials of C (cyan), M (magenta), Y (yellow), and K (black). In such an image output apparatus, CMYK colors are used. An image is output based on the output image data of the space. In this way, even if the color space used by the apparatus is different, or even if the image data has the same value in the same color space, the color expressed depending on the type of apparatus or machine difference may be slightly different. That is, the above-described RGB color space and CMYK color space are device-dependent color spaces, and even if an image is output by an image output device using input image data obtained by the image input device as it is, In general, the color of the input original image and the color of the image output by the image output apparatus do not match. Therefore, when trying to reproduce the original image with the image output device, it is necessary to convert the image data between the image input device and the image output device instead of sending the image data obtained by the image input device to the image output device as it is. is there. Here, attention is paid to the color of the image, and this conversion of the image data is referred to as color conversion.

When performing color conversion, a common color space that does not depend on the device, for example, an L ^* a ^* b ^* color space or the like is placed in the middle, and an image in an input color space (eg, RGB color space) that depends on the image input device. A general method is to convert data into image data in a common color space, and convert the converted image data in the common color space into image data in an output color space (for example, CMYK color space) depending on the image output device. Has been adopted. Also, the manufacturer that manufactures the image output device is usually provided with an input profile in which the image data in the input color space is associated with the image data in the common color space from the manufacturer that manufactures the image input device. Thus, an output profile in which image data in the output color space and image data in the common color space are associated with each other is provided. In a color conversion device provided between an image input device and an image output device, image data in an input color space obtained by reading an original image by the image input device is converted into image data in a common color space according to an input profile. Further, image data in the output color space associated with the image data in the common color space in the output profile is acquired. The acquired image data of the output color space is sent to the image output device, and an image is output by the image output device based on the image data, thereby eliminating the trouble of manually fine-tuning the degree of color conversion and the like. In addition, even an operator who does not have a skilled technique can easily obtain an image in which the color of the original image is accurately reproduced. Such color conversion is also effective when diverting image data for one image output device to another image output device, and the above input color space and input profile are independent of the type of device. It often means that used in the first half of color conversion.

  By the way, in the field of printing, an image represented by input image data is not output as it is by the image output device, but a page composed of images, characters, etc. represented by the input image data is edited by the operator. In general, a print image is output based on page data representing. The page data is an image of a page expressed by a set of parts such as characters and images constituting the page, and is configured by a set of data representing each part. Examples of the image data constituting such page data include image data representing an image read by a scanner, color data expressed in an RGB color space depending on the scanner, and photographing of a subject taken by a digital camera. Image data of various input color spaces, such as image data representing colors in an RGB color space depending on a digital camera representing an image, are mixed. Further, PS (Post Script) is a de facto standard in the page description language for describing page data, and the PS language specification defines a format for defining various parameters corresponding to the above-described input profile and output profile. Is predetermined. In a color conversion apparatus capable of executing instructions described in PS, when various parameters defined in a format that conforms to the language specification of PS are specified by an operator, page data is output using the various parameters as output image data. The color is converted to.

  FIG. 1 is a diagram showing an outline of a color conversion function for converting page data into output image data.

  As described above, the page data is composed of a set of image data in various input color spaces. In FIG. 1, a color conversion process for image data in one input color space (RGB color space) will be described on behalf of the image data in the plurality of input color spaces.

  A CIEBasedABC parameter 10 shown in FIG. 1 is a parameter corresponding to the above-described input profile, and a correspondence relationship between image data in the input color space (RGB color space) and image data in the common color space (XYZ color space) is predetermined. It is defined in the format. A CRD (color rendering dictionary) parameter 11 is a parameter corresponding to the above-described output profile, and a correspondence relationship between image data in the common color space and image data in the output color space (CMYK color space) is defined in a predetermined format. ing.

  In the example shown in FIG. 1, image data in the RGB color space is converted into image data in the XYZ color space based on the CIEBasedABC parameter 10, and further, the image data in the XYZ color space is converted into the CMYK color space based on the CRD parameter 11. Converted to image data. By using this color conversion function, the operator can easily convert page data described in PS into output image data simply by specifying the CIEBasedABC parameter 10 and the CRD parameter 11.

  However, the color reproduction area (hereinafter referred to as output gamut) that can be expressed by the image output apparatus is generally narrower than the color reproduction area (hereinafter referred to as input gamut) that can be expressed by the image input apparatus. As shown in FIG. 1, if color conversion is performed simply focusing on the point of “equal color”, the color near the boundary of the output gamut is crushed and the color tone becomes discontinuous. .

Regarding this problem, among the colors in the input color space, the colors in the common area of the input gamut and the output gamut are converted into colors in the output color space with emphasis on “equal color”. A technique for converting the color of the output color space with emphasis on “color gradation” is known (see, for example, Patent Document 1). According to this technology, since the color of the input color space is directly associated with the color of the output color space, it is possible to reduce inconveniences such as discontinuity in color tone and an image with an unnatural impression. In addition, the processing time for the color conversion process can be reduced.
JP 2004-349838 A

  Here, the technique described in Patent Document 1 requires a device link profile in which input color space image data and output color space image data are directly associated with each other. However, in the PS language specification, a parameter (CIEBasedABC parameter 10) in which a correspondence relationship between image data in the input color space and image data in the common color space is defined, image data in the common color space, and image data in the output color space. It is assumed that a parameter (CRD parameter 11) for which the correspondence relationship is defined is specified, and the parameter corresponding to the device link profile is not scheduled to be used. For this reason, when high-accuracy color conversion is required, the captured image data acquired by the digital camera or the graphic image data generated using a computer before the page data is created. The color conversion processing using the device link profile is performed one by one, which is inefficient and the color conversion function prepared in the color conversion device for PS is not used and is wasted. Currently.

  In view of the above circumstances, the present invention provides a parameter providing apparatus and a color conversion system that can reproduce the color of an original image with high accuracy by using a color conversion function that is standardly prepared in a PS color conversion apparatus. An object is to provide a parameter providing program and a color conversion program.

The parameter providing apparatus of the present invention that achieves the above object performs coordinate conversion between a first color space dependent on a first device and a same-dimensional color space having the same dimension as the first color space. Providing a first parameter defined in a format and a second parameter defining a coordinate transformation between the same-dimensional color space and a second color space dependent on the second device in a predetermined second format In response, the color conversion device that converts the input image data in which the color is defined in the first color space into the output image data in which the color is defined in the second color space, the first parameter, the second parameter, In the parameter providing device for providing
A parameter acquisition unit that acquires a direct parameter defining a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides an identity parameter defining an identity transformation of coordinates in a first color space in a first format to the color conversion device in place of the first parameter;
And a second providing unit that converts the format of the direct parameter acquired by the parameter acquiring unit into the second format and provides the converted direct parameter to the color conversion device in place of the second parameter. And

  According to the parameter providing apparatus of the present invention, the coordinate conversion between the first color space and the same-dimensional color space is replaced with the first parameter defined in the first format, and the coordinates of the first color space are identical. An identity parameter is provided that defines the transformation in its first form, and the coordinate transformation between the same dimensional color space and the second color space is replaced with a second parameter defined in a predetermined second form, A direct parameter defining a direct coordinate transformation between one color space and a second color space in its second form is provided, so that in the color conversion device, the first color is determined by the identity parameter. The coordinates of the space are converted as they are into the same coordinates of the first color space, and the coordinates of the first color space are converted directly into the coordinates of the second color space by direct parameters. In the PS language specification, it is required to specify the CIEBasedABC parameter and the CRD parameter corresponding to the first parameter and the second parameter. Therefore, the identity parameter is defined in the first format, and the direct parameter By defining the device link profile as a type in the second format, the device link profile can be used in the PS color conversion device, and it can be used as it is without changing the color conversion device. Can be realized.

Further, in the parameter providing apparatus of the present invention, “including a direct parameter selection unit that selects one direct parameter among a plurality of direct parameters according to an operation,
It is preferable that the parameter acquisition unit acquires the direct parameter selected by the direct parameter selection unit.

  Normally, a color conversion device has a device link profile that defines direct coordinate conversion between an input color space that depends on an image input device such as a scanner and an output color space that depends on an image output device such as a printer. The image input device and the image output device are provided for each pair. According to the parameter providing apparatus including the direct parameter acquisition unit, the operator can select a device link profile corresponding to a pair of an image input apparatus that acquires an image and an image output apparatus that outputs an image from a plurality of device link profiles. By selecting, it is possible to easily specify a direct parameter for executing a desired color conversion.

In the parameter providing apparatus according to the present invention, “a third color space that defines coordinate conversion between the first color space and a third color space that is the same dimension as the first color space and is device independent” is defined. A third parameter selection unit that selects the parameters of
A fourth parameter selection unit that selects a fourth parameter that defines coordinate transformation between the third color space and the second color space according to an operation;
A direct parameter generation unit that directly generates a parameter based on the third parameter set by the third parameter selection unit and the fourth parameter set by the fourth parameter selection unit;
It is preferable that the parameter acquisition unit acquires the direct parameter generated by the direct parameter generation unit.

  In the language specification of PS, in order to instruct color conversion processing, it is required to specify a parameter corresponding to the first parameter and a parameter corresponding to the second parameter. These parameters are provided to the PS color converter by user selection. By the way, the third parameter defines the coordinate transformation between the first color space and the device-independent color space, like the first parameter, and the fourth parameter is the second parameter. Since the coordinate conversion between the device-independent color space and the second color space is defined in the same manner as the above parameters, the first parameter, the third parameter, the second parameter, and the second parameter space are defined. The parameter 4 is sensuously similar to the user. According to the parameter providing device provided with the direct parameter generation unit, the user can select the third parameter and the fourth parameter according to the operation as if selecting the first parameter and the second parameter. High-precision color reproduction can be realized without being aware of changes.

The color conversion system of the present invention that achieves the above object performs predetermined coordinate conversion between a first color space depending on the first device and a same-dimensional color space having the same dimension as the first color space. A first reception unit that receives the first parameter defined in the first format of
A second reception unit that receives provision of a second parameter defined in a predetermined second format for coordinate transformation between the same-dimensional color space and a second color space depending on the second device;
A first color for converting input image data whose color is defined in the first color space into intermediate image data whose color is defined in the same dimensional color space using the parameters provided by the first receiving unit A conversion unit;
A second color conversion unit that converts the intermediate image data into output image data in which a color is defined in the second color space, using parameters provided by the second reception unit;
A parameter acquisition unit that acquires a direct parameter defining a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides an identity parameter in which the identity transformation of the coordinates of the first color space is defined in a first format to the first accepting unit instead of the first parameter;
A second providing unit that converts the format of the direct parameter acquired by the parameter acquiring unit to the second format and provides the converted direct parameter to the second receiving unit instead of the second parameter; It is characterized by.

  According to the color conversion system of the present invention, the direct parameters defining the direct coordinate conversion between the first color space and the second color space are provided to the color conversion unit in a format suitable for the PS language specification, for example. The color of the original image can be reproduced with high accuracy.

  Note that the color conversion system is shown only in its basic form here, but this is only for avoiding duplication, and the color conversion system according to the present invention is not limited to the above basic form. Various forms corresponding to each form of the parameter providing apparatus are included.

The parameter providing program of the present invention that achieves the above object is executed in a computer, and the first color space depending on the first device and the same dimensional color of the same dimension as the first color space are executed on the computer. A first parameter that defines the coordinate transformation between the space and the second color space that depends on the second device and a second parameter that depends on the second parameter. A color conversion device that receives input of the second parameter defined in the format and converts the input image data in which the color is defined in the first color space into output image data in which the color is defined in the second color space In the parameter providing program for constructing the parameter providing apparatus that provides the first parameter and the second parameter,
A parameter acquisition unit that acquires a direct parameter defining a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides an identity parameter defining an identity transformation of coordinates in a first color space in a first format to the color conversion device in place of the first parameter;
A structure is provided in which a direct parameter format acquired by the parameter acquisition unit is converted into a second format and the converted direct parameter is provided to the color conversion device in place of the second parameter. And

  According to the parameter providing program of the present invention, a parameter for reproducing the color of the original image with high accuracy can be provided to the color conversion apparatus.

  Note that only the basic form of the parameter providing program is shown here, but this is only for avoiding duplication, and the parameter providing program referred to in the present invention is not limited to the above basic form. Various forms corresponding to each form of the parameter providing apparatus are included.

  In addition, an element such as a parameter acquisition unit constructed on the computer system by the parameter providing program of the present invention may be one element constructed by one program part, and a plurality of elements are one program part. It may be constructed by. In addition, these elements may be constructed so as to execute such actions by themselves, or constructed by giving instructions to other programs and program components incorporated in the computer system. May be.

Further, the color conversion program of the present invention that achieves the above object is executed in a computer, and on the computer,
A first parameter defined in a predetermined first format is provided for coordinate transformation between a first color space depending on the first device and a same color space having the same dimension as the first color space. 1 reception department,
A second receiving unit that receives provision of a second parameter that defines a coordinate transformation between the same-dimensional color space and a second color space depending on the second device in a predetermined second format;
A first color for converting input image data whose color is defined in the first color space into intermediate image data whose color is defined in the same dimensional color space using the parameters provided by the first receiving unit A conversion unit;
A second color conversion unit that converts the intermediate image data into output image data in which a color is defined in the second color space, using parameters provided by the second reception unit;
A parameter acquisition unit that acquires a direct parameter defining a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides an identity parameter in which the identity transformation of the coordinates of the first color space is defined in a first format to the first accepting unit instead of the first parameter;
Converting the format of the direct parameter acquired by the parameter acquiring unit to the second format, and constructing a second providing unit that provides the converted direct parameter to the second receiving unit in place of the second parameter It is characterized by.

  According to the color conversion program of the present invention, input image data can be converted into output image data with high accuracy.

  The color conversion program is shown only in its basic form here, but this is only for avoiding duplication, and the color conversion program referred to in the present invention is not limited to the above basic form. Various forms corresponding to each form of the parameter providing apparatus are included.

  In addition, the element such as a parameter acquisition unit constructed on the computer system by the color conversion program of the present invention may be one element constructed by one program part, and a plurality of elements are one program part. It may be constructed by. In addition, these elements may be constructed so as to execute such actions by themselves, or constructed by giving instructions to other programs and program components incorporated in the computer system. May be.

  As described above, according to the present invention, a parameter providing apparatus, a color conversion system, and a parameter that can reproduce the color of an original image with high accuracy by using a color conversion function that is standardly prepared for PS. A provided program and a color conversion program are obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 2 is a diagram showing an image output system in which an embodiment of the present invention is incorporated.

  In the image output system shown in FIG. 2, the client device 300, the print printer server device 100, and the printer 202 are connected via the communication network 20, and the scanner 201 is also connected to the client device 300.

  The scanner 201 reads an original image using light of R, G, and B colors, and generates original image data in the RGB color space. The scanner 201 is an example of a first device according to the present invention, and the RGB color space corresponds to an example of the first color space according to the present invention. The generated original image data is transmitted to the client device 300.

  The client apparatus 300 receives original image data generated by reading an original image by the scanner 201, captured image data generated by photographing a subject with a digital camera (not shown), and the like. In client apparatus 300, the page including the image represented by the input image data is edited by the operator, and input image data representing the image of the edited page is generated. The input image data is an image of a page expressed by a set of parts such as characters and images constituting the page. For example, an RGB color space depending on the scanner 201 representing an image read by the scanner 201. Various input color spaces, such as image data in which colors are expressed in, and image data in which colors are expressed in RGB color space depending on the digital camera, representing a photographed image obtained by photographing a subject with a digital camera (not shown) Image data. For convenience of explanation, in this embodiment, PS is applied as a page description language for describing a page, and input image data is page data composed only of image data in the RGB color space generated by the scanner 201. Will be described. When the editing is completed, the operator inputs a print instruction for printing out an image based on the input image data, and the client apparatus 300 sends the print instruction and the input image data to the printer server apparatus 100.

  The printer server apparatus 100 receives input image data from the client apparatus 300 and converts the input image data into output image data for the printer 202 that represents a page with a raster image. In the present embodiment, the printer 202 outputs an image using C, M, Y, and K4 color materials. In the printer server apparatus 100, input image data in the RGB color space is converted into an output image in the CMYK color space. A description will be given assuming that the data is to be converted. The converted output image data is sent to the printer 202. The input image data may be received from a client device 300 via a communication network 20 using a storage medium such as a CD-R (Compact Disc Recordable) or an MO (magneto-optical) disk. .

  When the output image data is sent from the printer server apparatus 100, the printer 202 prints out the page represented by the output image data. The printer 202 is an example of the second device according to the present invention, and the CMYK color space depending on the printer 202 corresponds to an example of the second color space according to the present invention.

  Here, the feature of the image output system shown in FIG. 2 as an embodiment of the present invention is mainly the contents of processing executed in the printer server apparatus 100. Hereinafter, the printer server apparatus 100 will be described. Will be described.

  The printer server apparatus 100 shown in FIG. 2 has a main body apparatus 101, an image display apparatus 102 that displays an image on a display screen in response to an instruction from the main body apparatus 101, and a main body apparatus 101 according to key operations. A keyboard 103 for inputting various information and a mouse 104 for inputting an instruction corresponding to an icon or the like displayed at the position by designating an arbitrary position on the display screen are provided. In addition, the main unit 101 has an FD loading port for loading a flexible disk (hereinafter abbreviated as FD) and a CD-ROM loading port for loading a CD-ROM.

  FIG. 3 is a hardware configuration diagram of the printer server apparatus 100.

  As shown in FIG. 3, the main unit 101 includes a CPU 111 that executes various programs, a main memory 112 that reads programs stored in the hard disk device 113 and develops them for execution by the CPU 111, and various programs 2 is connected to the FD drive 114 that accesses the loaded FD 400, the CD-ROM drive 115 that accesses the CD-ROM 410, and the client device 300 of FIG. An input interface 116 for receiving image data and the like from the client apparatus 300, and an output interface 117 for connecting the printer 202 in FIG. 2 to send image data to the printer 202 are built in. These various elements are further shown in FIG. Image display device 02, a keyboard 103, and mouse 104 are connected to each other via a bus 105.

  Here, the CD-ROM 410 incorporates an embodiment of the parameter providing program of the present invention, and stores a printer server program which is an embodiment of the color conversion program. The CD-ROM 410 is loaded into the CD-ROM drive 115, and the printer server program stored in the CD-ROM 410 is uploaded to the printer server device 100 and stored in the hard disk device 113. Then, when the printer server program is started and executed, an embodiment of the color conversion system of the present invention in which the embodiment of the parameter providing apparatus of the present invention is incorporated in the printer server apparatus 100 is constructed. Is done.

  In the above, the CD-ROM 410 is exemplified as the storage medium for storing the printer server program. However, the storage medium for storing the parameter providing program and the color conversion program of the present invention is not limited to the CD-ROM. Other storage media such as an optical disk, MO, FD, and magnetic tape may be used. The parameter providing program and the color conversion program of the present invention may be directly supplied to the printer server apparatus 100 via the input interface 116 without using a storage medium.

  Next, the printer server program will be described.

  FIG. 4 is a conceptual diagram showing the CD-ROM 410 in which the printer server program is stored.

  As shown in FIG. 4, the printer server program 500 stored in the CD-ROM 410 includes an input unit 510, a job control unit 520, a profile creation unit 530, an instruction PS generation unit 540, and a color conversion unit 550. .

  Details of each part of the printer server program 500 will be described together with the operation of each part of the printer server apparatus 100.

  FIG. 5 is a functional block diagram of the printer server apparatus 100.

  The printer server apparatus 100 includes an input unit 121, a job control unit 122, a profile creation unit 123, an instruction PS generation unit 124, and a color conversion unit 125.

  The input unit 121, the job control unit 122, the profile creation unit 123, the instruction PS generation unit 124, and the color conversion unit 125 that configure the printer server apparatus 100 configure the printer server program 500 illustrated in FIG. These correspond to the input unit 510, job control unit 520, profile creation unit 530, instruction PS generation unit 540, and color conversion unit 550, respectively.

  Each element of the printer server apparatus 100 shown in FIG. 5 is constructed on a computer by each element of the printer server program 500 shown in FIG. 4, and the hardware of the computer and the OS and application program executed on the computer. 4 in that each element of the printer server program 500 shown in FIG. 4 is configured only by the application program.

  The instruction PS generation unit 124 shown in FIG. 5 corresponds to an embodiment of the parameter providing apparatus of the present invention, and the combination of the instruction PS generation unit 124 and the color conversion unit 125 is an embodiment of the color conversion system of the present invention. It corresponds to.

  Hereinafter, by describing each element of the printer server apparatus 100 illustrated in FIG. 5, each element of the printer server program 500 illustrated in FIG. 4 is also described.

  As described with reference to FIG. 1, in the PS language specification, as a parameter for executing the color conversion process, the correspondence between the image data in the input color space and the image data in the common color space is expressed in a predetermined parameter format ( It is required to specify the CIEBasedABC parameter 10 defined in (described later) and the CRD parameter 11 in which the correspondence between the image data in the common color space and the image data in the output color space is defined in a predetermined parameter format (described later). It has been. However, in order to realize high-accuracy color conversion processing, it is necessary to convert image data in the input color space directly into image data in the output color space without going through the common color space. In the printer server device 100 of the present embodiment, image data in the input color space is directly converted into image data in the output color space using two parameters defined in the same parameter format as the CIEBasedABC parameter 10 and the CRD parameter 11 respectively. To be done.

  The client apparatus 300 sends to the printer server apparatus 100 input image data and a print instruction for printing out an image based on the input image data. The input image data is acquired by the input unit 121 illustrated in FIG. 5, and the print instruction is acquired by the job control unit 122.

  In the printer server apparatus 100, a plurality of print instructions are input from each of the plurality of client apparatuses 300, and a job for printing out an image is executed according to each of the plurality of print instructions. When a print instruction is sent from the client device 300, the job control unit 122 assigns a job ID to a job that prints an image in accordance with the print instruction, and the priority of the job and processing when the job is executed Edit the job ticket that shows the procedure. In the printer server apparatus 100, the job is executed in accordance with the priority order and processing procedure indicated in the job ticket. The edited job ticket is registered in association with the job ID.

  The input unit 121 transmits the input image data sent from the client device 300 to the color conversion unit 125.

  The printer server apparatus 100 includes image data in an input color space (for example, RGB color space) depending on the scanner 201 or the like that inputs image data to the client apparatus 300, and a common color space (for example, XYZ) that is independent of the device. Correspondence between input profile indicating correspondence relationship with image data in color space), image data in common color space, and image data in output color space (for example, CMYK color space) depending on printer 202 that outputs the image And a plurality of device link profiles indicating a direct correspondence between the image data in the input color space and the image data in the output color space are stored. Further, the printer server apparatus 100 selects one set of input profile and output profile combination or one device link profile from among a plurality of input profiles, output profiles, and device link profiles respectively stored therein. The selection screen is prepared.

  Here, the description of FIG. 5 is temporarily interrupted, and selection of various profiles will be described.

  FIG. 6 is a diagram illustrating an example of a profile selection screen.

  The profile selection screen 600 includes an input profile selection unit 610 for selecting an input profile, an output profile selection unit 620 for selecting an output profile, and a device link profile selection unit 630 for selecting a device link profile. It has been. In the selection units 610, 620, and 630, when various profiles are added to the input image data sent from the client apparatus 300, check boxes 611 for preferentially using the added profiles. 621 and 631, and selection boxes 612, 622, and 632 for selecting a desired profile from various profiles stored in advance in the printer server apparatus 100.

  When selecting a combination of an input profile and an output profile, the operator designates the input-output radio button 641 using the mouse 104 or the keyboard 103, and each of the input profile selection unit 610 and the output profile selection unit 620. In the selection boxes 612 and 622, an input profile corresponding to a desired image input device (in the present embodiment, the scanner 201) and an output profile corresponding to the desired image output device (in the present embodiment, the printer 202) are designated. . When selecting a device link profile, the device link radio button 642 is designated, and a desired image input device (scanner 201 in the present embodiment) and image are selected in the selection box 632 of the device link profile selection unit 630. A device link profile corresponding to the output device (the printer 202 in this embodiment) is designated. The specified contents are transmitted to the profile creation unit 123 and the instruction PS generation unit 124 shown in FIG. The mouse 104 and the keyboard 103 correspond to an example of a direct parameter selection unit according to the present invention.

  As described above, by preparing a plurality of profiles in advance and selecting a profile corresponding to the set of the scanner 201 and the printer 202 from among them, the operator needs a high level of knowledge about the color conversion processing. Without being necessary, the color conversion process can be easily executed.

  Returning to FIG.

  When a combination of an input profile and an output profile is selected by the operator, these profiles are transmitted to the profile creation unit 123, and a device link profile is generated in the profile creation unit 123. Since the color reproduction area (input gamut) of the scanner 201 and the color reproduction area (output gamut) of the printer 202 generally do not coincide with each other, if the input profile and the output profile are simply connected, gradation loss and There is a risk of tone jumping. In the profile creation unit 123, among the colors expressed in the input color space, the color included in the central portion of the common area between the input gamut and the output gamut is a color expressed in the output color space with an emphasis on “equal color”. A device link profile is generated for converting the color of the region excluding the central portion from the color expressed in the input color space into a color expressed in the output color space with emphasis on “gradation”. Note that generation of a device link profile is a technique that has been widely performed in the past, and thus detailed description thereof is omitted in this specification. The generated device link profile is transmitted to the instruction PS generation unit 124.

  The instruction PS generation unit 124 includes a first parameter provision unit 1243, a parameter acquisition unit 1241, a second parameter provision unit 1242, and a PS generation unit 1244.

  In the PS language specification, the minimum required description format of the CIEBasedABC parameter 10 shown in FIG. 1 is determined as follows.

[/ CIEBasedABC << WhitePoint [x y z] >>]
This description indicates an instruction to convert the input color space (RGB color space) into a common color space by matching the coordinates of the white point with [x yz]. Conventionally, based on the input profile, [x The coordinates of the white point of the common color space are designated in [yz], and the CIEBasedABC parameter 10 is generated. According to the CIEBasedABC parameter 10, RGB color space image data is converted into XYZ color space image data as shown in FIG.

  The first parameter providing unit 1243 generates an identity parameter in which [1 1 1] is specified in [x yz] in the above description instead of the CIEBasedABC parameter 10, and the generated identity parameter is a PS generation unit. 1244. This identity parameter is derived from the fact that the coordinates of the white point in the RGB color space are [1 1 1], and an instruction to convert the input color space to the common color space while maintaining the coordinates of the white point. In other words, the identity transformation in which the common color space is the input color space itself is defined. According to the identity parameter, the input image data in the RGB color space is identically converted into image data having the same value. The first parameter providing unit 1243 corresponds to an example of the first providing unit referred to in the present invention.

  The parameter acquisition unit 1241 acquires the device link profile specified by the operator or the device link profile generated by the profile creation unit 123. The acquired device link profile is transmitted to the second parameter providing unit 1242. The parameter acquisition unit 1241 corresponds to an example of a parameter acquisition unit referred to in the present invention.

  In the PS language specification, the description format of the CRD parameter 11 shown in FIG. 1 is determined as a set of sub-parameters as follows.

(1) Three-dimensional × three-dimensional matrix called “MatrixABC” (2) Three one-dimensional LUTs called “EncodeABC”
(3) Three-dimensional LUT and one-dimensional LUT called “RenderTable”
Conventionally, these subparameters are acquired based on the output profile, and the CRD parameter 11 is generated. As shown in FIG. 1, the CRD parameter 11 converts image data in the XYZ color space into image data in the CMYK color space.

  On the other hand, the device link profile describes color conversion from three components in the input color space to four components in the output color space as follows.

(1 ′) Linear transformation by 3D × 3D matrix (2 ′) Transformation by three 1D LUTs corresponding to each of the three components obtained by the linear transformation of (1 ′) (3′-1) Three Four components obtained by three-dimensional to four-dimensional conversion by (3'-2) and (3'-1) three-dimensional to four-dimensional conversion by LUT having four component output values for input values consisting of components Conversion by Four One-Dimensional LUTs Corresponding to Each The second parameter providing unit 1242 determines (1 ′), (2 ′), (3′-1), (3 ′) from the device link profile sent from the parameter acquisition unit 1241. Each LUT shown in 3′-2) is acquired. Further, the second parameter providing unit 1242 designates the 3D × 3D matrix shown in (1 ′) as the “MatrixABC” parameter shown in (1), and sets “EncodeABC” shown in (2) as (2 ′). Specify the three one-dimensional LUTs shown, specify the three-dimensional LUT shown in (3'-1) and the four one-dimensional LUTs shown in (3'-2) as "RenderTable" shown in (3), and directly set the parameters And the generated direct parameter is transmitted to the PS generation unit 1244 instead of the CRD parameter 11 shown in FIG. This direct parameter defines a direct coordinate transformation between the input color space and the output color space. According to this direct parameter, the input image data in the RGB color space is converted into the output image data in the CMYK color space. Converted directly to The second parameter providing unit 1242 corresponds to an example of a second providing unit referred to in the present invention.

  The PS generation unit 1244 generates an instruction PS for executing the color conversion processing using the identity parameter transmitted from the first parameter providing unit 1243 and the direct parameter transmitted from the second parameter providing unit 1242. The generated instruction PS is transmitted to the color conversion unit 125.

  The color conversion unit 125 includes an instruction PS reception unit 1251, a data acquisition unit 1252, a first conversion unit 1253, a second conversion unit 1254, and a raster conversion unit 1255.

  The data acquisition unit 1252 acquires the input image data transmitted from the input unit 121 and transmits the input image data to the first conversion unit 1253.

  The instruction PS reception unit 1251 acquires the instruction PS generated by the instruction PS generation unit 124. The instruction PS includes an identity parameter and a direct parameter, and the instruction PS reception unit 1251 corresponds to an example of each of the first reception unit and the second reception unit according to the present invention. In the color conversion unit 125, processing is executed in accordance with the instruction PS.

  FIG. 7 is a conceptual diagram of color conversion processing executed in the color conversion unit 125.

  The first conversion unit 1253 performs color conversion processing on the input image data transmitted from the data acquisition unit 1252 using the identity parameter 12 in accordance with the instruction PS. In the first conversion unit 1253, input image data in the RGB color space is converted as it is into image data having the same value by the identity parameter 12. As shown in FIG. 7, the first conversion unit 1253 substantially converts the input image data in the RGB color space as it is, but the PS language format shows the RGB color space as shown in FIG. This conversion is equivalent to the conversion from the image data to image data in the XYZ color space.

  In addition, the second conversion unit 1254 performs color conversion processing according to the direct parameter 13 included in the instruction PS, on the image data converted by the first conversion unit 1253. The second conversion unit 1254 converts the three-dimensional color space image data into the CMYK color space image data by the direct parameter 13. As shown in FIG. 7, in the second conversion unit 1254, the input image data in the RGB color space is substantially converted into the output image data in the CMYK color space. However, in terms of the PS language format, as shown in FIG. The conversion is equivalent to the conversion from the image data in the XYZ color space to the image data in the CMYK color space. The first conversion unit 1253 and the second conversion unit 1254 correspond to examples of the first color conversion unit and the second color conversion unit referred to in the present invention. The first conversion unit 1253 and the second conversion unit 1254 As the unit 1254, a conventional PS color conversion device can be used as it is. The converted image data in the CMYK color space is transmitted to the raster conversion unit 1255.

  As described above, the input image data is page data in which an image of a printed page is represented by a set of components such as characters and images constituting the page, and an output image generated by color conversion of the input image data. The data is also page data composed of a set of image data representing each of a plurality of parts. Accordingly, the output image data cannot be output by the printer 202 that outputs a page for each scanning line as it is. The raster conversion unit 1255 converts the image data in the CMYK color space transmitted from the second conversion unit 1254 into raster format image data.

  The image data converted into the raster format is output to the printer 202, and the printer 202 outputs the image represented by the image data.

  As described above, in the present embodiment, it is possible to execute high-precision color conversion processing using a device link profile by using a color conversion function that is standardly prepared in a PS color conversion apparatus. .

  Here, an example in which the RGB color space is applied as the input color space, the XYZ color space is applied as the common color space, and the CMYK color space is applied as the output color space has been described above. The color space, the same dimensional color space, and the second color space are not limited to these as long as the dimensions of the first color space and the same color space are the same.

  In the above description, an example in which a scanner is applied as an input device and a printer is applied as an output device has been described. However, the first device in the present invention may be a digital camera or the like that captures a subject. The second device referred to in the invention may be a printing machine or the like.

  In the above description, an example in which parameter provision and color conversion processing are performed in one printer server apparatus 100 has been described. However, the parameter provision apparatus and the color conversion apparatus according to the present invention are configured on separate apparatuses. May be.

It is a figure which shows the outline | summary of the color conversion function which converts page data into output image data. It is a figure which shows the image output system incorporating one Embodiment of this invention. It is a hardware block diagram of a printer server apparatus. It is a conceptual diagram which shows CD-ROM in which the printer server program was memorize | stored. It is a functional block diagram of a printer server apparatus. It is a figure which shows an example of a profile selection screen. It is a conceptual diagram of the color conversion process performed in a color conversion part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Printer server apparatus 101 Main body apparatus 102 Image display apparatus 103 Keyboard 104 Mouse 105 Bus 111 CPU
112 Main memory 113 Hard disk device 114 FD drive 115 CD-ROM drive 116 Input interface 117 Output interface 121 Input unit 122 Job control unit 123 Profile creation unit 124 Instruction PS generation unit 1241 Parameter acquisition unit 1242 Second parameter provision unit 1243 First parameter Provision unit 1244 PS generation unit 125 Color conversion unit 1251 Instruction PS reception unit 1252 Data acquisition unit 1253 First conversion unit 1254 Second conversion unit 1255 Raster conversion unit 201 Scanner 202 Printer 300 Client device 500 Printer server program 510 Input unit 520 Job control Section 530 Profile creation section 540 Instruction PS generation section 550 Color conversion section

Claims (6)

A first parameter defining a coordinate conversion between a first color space dependent on the first device and a same color space having the same dimension as the first color space in a predetermined first format; In response to the provision of a second parameter that defines a coordinate transformation between the dimensional color space and the second device-dependent second color space in a predetermined second format, the color in the first color space In a parameter providing device for providing the first parameter and the second parameter to a color conversion device that converts input image data in which color is defined into output image data in which a color is defined in the second color space ,
A parameter acquisition unit that acquires a direct parameter that defines a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides, as the first parameter, an identity parameter that defines an identity transformation of coordinates of the first color space in the first format;
A second providing unit that converts the format of the direct parameter acquired by the parameter acquiring unit into the second format and provides the converted direct parameter to the color conversion apparatus as the second parameter ; A parameter providing device. A direct parameter selection unit that selects one direct parameter among a plurality of direct parameters according to an operation;
The parameter providing apparatus according to claim 1, wherein the parameter acquisition unit acquires a direct parameter selected by the direct parameter selection unit. A third parameter that defines coordinate transformation between the first color space and a third color space that is the same dimension as the first color space and is device-independent is selected according to an operation. A third parameter selection unit;
A fourth parameter selection unit that selects a fourth parameter that defines coordinate transformation between the third color space and the second color space according to an operation;
A direct parameter generation unit that generates the direct parameter based on the third parameter set by the third parameter selection unit and the fourth parameter set by the fourth parameter selection unit;
The parameter providing apparatus according to claim 1, wherein the parameter acquisition unit acquires a direct parameter generated by the direct parameter generation unit. A first parameter defined in a predetermined first format is provided for coordinate transformation between a first color space depending on the first device and the same color space having the same dimension as the first color space. A first reception unit;
A second reception unit that receives provision of a second parameter defined in a predetermined second format for coordinate transformation between the same-dimensional color space and a second color space depending on the second device;
First, the input image data whose color is defined in the first color space is converted into intermediate image data whose color is defined in the same dimensional color space, using the parameters provided by the first receiving unit. 1 color conversion unit;
A second color conversion unit that converts the intermediate image data into output image data in which a color is defined in the second color space, using parameters provided by the second reception unit;
A parameter acquisition unit that acquires a direct parameter that defines a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides, as the first parameter, an identity parameter that defines identity transformation of the coordinates of the first color space in the first format;
Converting the format of the direct parameters acquired by the parameter acquisition unit to the second format, and a second providing unit that provides a direct parameter that converts the second parameter to the second receiving unit A color conversion system characterized by that. Coordinate transformation between a first color space dependent on a first device and a same color space having the same dimension as the first color space is executed in the computer and has a predetermined first format. And a second parameter defining a coordinate conversion between the same-dimensional color space and a second color space depending on the second device in a predetermined second format. In response, the color conversion device that converts the input image data in which the color is defined in the first color space into the output image data in which the color is defined in the second color space, the first parameter and the first In a parameter providing program for constructing a parameter providing apparatus that provides two parameters,
A parameter acquisition unit that acquires a direct parameter that defines a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides, as the first parameter, an identity parameter that defines an identity transformation of coordinates of the first color space in the first format;
Constructing a second providing unit the converted format of the direct parameters acquired by the parameter acquisition unit to the second format, and provides the converted direct parameter as the second parameter to the color conversion device A parameter providing program characterized by Executed in a computer, on the computer,
A first parameter defined in a predetermined first format is provided for coordinate transformation between a first color space depending on the first device and the same color space having the same dimension as the first color space. A first reception unit;
A second reception unit that receives provision of a second parameter defined in a predetermined second format for coordinate transformation between the same-dimensional color space and a second color space depending on the second device;
First, the input image data whose color is defined in the first color space is converted into intermediate image data whose color is defined in the same dimensional color space, using the parameters provided by the first receiving unit. 1 color conversion unit;
A second color conversion unit that converts the intermediate image data into output image data in which a color is defined in the second color space, using parameters provided by the second reception unit;
A parameter acquisition unit that acquires a direct parameter that defines a direct coordinate transformation between the first color space and the second color space;
A first providing unit that provides, as the first parameter, an identity parameter that defines identity transformation of the coordinates of the first color space in the first format;
Building a second providing unit the have been in the form of direct parameters acquired by the parameter acquisition unit into a second format, provides a direct parameter that converts the second parameter to the second receiving unit A color conversion program characterized by:

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