JP2011182136A - Device, method and program for processing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor or the like, for converting input data represented by an input color space to output data represented by an output color space. <P>SOLUTION: This device for processing an image for converting input data represented by an input color space to output data represented by an output color space is equipped with: a first storage part storing first conversion information for converting a first color space to a second color space; a second storage part for storing second conversion information for converting the second color space to the output color space; and a conversion means to convert the input data to the output data using the second conversion information when the input color space of the input data is the second color space. In the device for processing an image, when the input color space of the input data is the first color space, the conversion means converts the input data to the output data by using the first conversion information and the second conversion information. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing method, and an image processing program.

  Conventionally, when input data such as an image is output by a printer or the like, output data is generated by performing image processing such as color conversion processing on the input data, and output processing is executed based on the output data To do.

  The color conversion process is a process for converting a gradation image defined in a certain color space into a gradation image defined in another color space. For example, while input data generated by a host device or the like is defined in the RGB color space, the output device (for example, a printer) executes printing based on the output data defined in the CMYK color space. Processing is required. As a color conversion method, conversion information (LUT: Look-up Table) in which color values in a color space before conversion and color values in a color space after conversion are associated is prepared, and the LUT is referred to. The color conversion method is generally used (see, for example, Patent Document 1).

JP 2005-286904 A

  Here, for example, in a printer that processes input data expressed in a plurality of color spaces, it is necessary to prepare a plurality of LUTs for converting each color space into an output color space depending on the printer model.

  In addition, even in the same color space, when it is desirable to change the processing contents according to the type of input data, for example, when preparing a text LUT and an image LUT for the same color space, The number of the plurality of LUTs further increases.

  Therefore, in order to hold these multiple LUTs, the printer needs a memory having a large storage capacity. In particular, the color space used in the printer is usually a four-dimensional CMYK color space, and there is a tendency that the data amount of each LUT converted into the four-dimensional color space is large.

  Further, as described above, since the output color space depends on the model of the printer, it is necessary to design the plurality of LUTs for each model, which takes time and effort of the designer.

  Therefore, the present invention is an image processing apparatus or the like that converts input data expressed in an input color space into output data expressed in an output color space, and the conversion information can be easily designed. It is an object of the present invention to provide an image processing apparatus or the like that can reduce the storage capacity.

  An image processing apparatus according to the present invention is an image processing apparatus that converts input data expressed in an input color space into output data expressed in an output color space, wherein the first color space is converted into a second color space. A first storage unit that stores first conversion information for conversion into the second color space; a second storage unit that stores second conversion information for converting the second color space into the output color space; and the input data Conversion means for converting the input data into output data using the second conversion information when the input color space is the second color space, and the conversion means includes the input color of the input data. When the space is the first color space, the input data is converted into output data using the first conversion information and the second conversion information.

  The first storage unit preferably stores a plurality of the first conversion information according to the type of the first color space.

  Furthermore, the image processing apparatus may include a detachable device unit, and the first storage unit may be disposed in the device unit.

  An image processing method according to the present invention is an image processing method for converting input data expressed in an input color space into output data expressed in an output color space, wherein the first color space is converted into the second color space. Storing the first conversion information for converting into the output color space, storing the second conversion information for converting the second color space into the output color space, and the input color space of the input data as the second color If it is a space, the input data is converted into output data using the second conversion information, and if the input color space of the input data is the first color space, the input data is converted to the first conversion information. And it converts into output data using the said 2nd conversion information.

  An image processing program according to the present invention is characterized by causing each step of the image processing method of the present invention to be executed on a computer. The program of the present invention can be installed or loaded on a computer through various recording media such as a CD-ROM, a magnetic disk, and a semiconductor memory.

It is the schematic which shows the hardware constitutions of the image processing system 1 of 1st Embodiment. It is a figure which shows an example of schematic structure of the image processing apparatus of 1st Embodiment. It is the schematic which shows the flow of the color conversion process of 1st Embodiment. It is a flowchart which shows the processing content of the image processing method of 1st Embodiment. It is the schematic which shows the hardware constitutions of image processing system 1 'in the modification of 1st Embodiment. It is a figure which shows an example of schematic structure of the image processing apparatus and apparatus unit in the modification of 1st Embodiment. It is the schematic which shows the hardware constitutions of the image processing system 2 of 2nd Embodiment. It is a figure which shows an example of schematic structure of the image processing apparatus of 2nd Embodiment. It is the schematic which shows the flow of the color conversion process of 2nd Embodiment. It is a flowchart which shows the processing content of the image processing method of 2nd Embodiment.

  Hereinafter, each preferred embodiment for carrying out the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram illustrating a hardware configuration of an image processing system 1 according to the present embodiment. The image processing system 1 includes a host computer 10 and a printer 20.

  The host computer 10 includes a printer driver 101 that issues a print request to the printer 20 and functions as a host device for the printer 20. The printer driver 101 generates input data (print target data) such as image data to the printer 20 in response to a user's print instruction operation, and transmits it to the printer 20. The printer driver 101 can be configured by a control device that executes processing according to a driver program describing the above processing. The configuration itself of the printer driver 101 can in principle be the same as the configuration of a printer driver used for a normal printer, and a detailed description thereof will be omitted.

  For example, the printer (image processing apparatus) 20 is connected to the host computer 10 via a communication network, receives input data expressed in the input color space from the host computer 10, and corresponds the input data to printing ink. The output data is converted into output data (print data) expressed in the output color space, and the output data is printed.

  Here, in the present embodiment, the output color space expressed by the output data is a CMYK color space depending on the model of the printer 20, and the input color space expressed by the input data is an RGB (1) color space, RGB (2) Color space (color space different from RGB (1) color space), CMYK (2), CMYK (3) color space (color space different from CMYK color space as output color space), and Lab color space One of the color spaces. Even in the case of CMYK, if the color materials such as ink and toner are different, the gradation density of the color value when representing the same color will be different, so the CMYK (2) color space and CMYK as described above. (3) may exist.

  The printer 20 includes a printer engine 21 and a printer controller 22. However, the printer controller 22 may be separated from the printer 20.

  The printer engine 21 has the same configuration as that of a normal printer engine. For example, a serial printer that prints in units of one character, such as an inkjet printer or a thermal transfer printer, a line printer that prints in units of lines, and a page unit Various printer engines corresponding to a page printer to be printed can be used.

  The printer controller 22 includes, for example, a CPU (Central Processing Unit) 201 that performs various calculations, a ROM 202 that stores various data and various programs in advance, a RAM 203 that temporarily stores programs executed by the CPU 201 or image data, and a host. A component such as an interface 204 for communicably connecting to an external device such as the computer 10 is provided.

  As shown in FIG. 2, the printer controller 22 functionally includes a receiving unit 221, a determining unit 222, a converting unit 223, a first storage unit 224, and a second storage unit 225. Each means such as the receiving means 221 is mainly realized by the CPU 201 executing a program stored in the ROM 202 or the RAM 203 and controlling each hardware, and the first storage unit 224 and the second storage unit 225 are It can be realized using the ROM 202 or the RAM 203.

  The first storage unit 224 stores first conversion information for converting the first color space to the second color space. The second color space is an RGB (1) color space (RGB color space). On the other hand, the first color space is an input color space excluding the RGB color space as the second color space, that is, the RGB (2) color space, the CMYK (2) color space, and the CMYK (3) color space. And the Lab color space. The first conversion information is conversion information (LUT: Look-up Table) in which color values in the first color space and color values in the second color space are associated with each other. A plurality of them are prepared. Specifically, the LUT “RGB (2) to RGB LUT” for converting from the RGB (2) color space to the RGB color space, and the LUT “CMYK ( 2) to RGB LUT ”, LUT“ CMYK (3) to RGB LUT ”for converting from the CMYK (3) color space to the RGB color space, and LUT“ Lab to ”for converting from the Lab color space to the RGB color space. RGB LUT ”.

  The second storage unit 225 stores second conversion information for converting the second color space to the output color space. That is, the second conversion information is an LUT “RGB to CMYK LUT” for converting from the RGB color space to the CMYK color space.

  The receiving unit 221 receives input data expressed in each input color space from the host computer 10.

  The determination unit 222 determines whether or not the input color space expressed by the input data received by the reception unit 221 is the first color space.

  When the input color space of the input data is the first color space as a result of the determination by the determination unit 222, the conversion unit 223 converts the input data into output data using the first conversion information and the second conversion information. When the input color space of the input data is the second color space, the input data is converted into output data using the second conversion information. FIG. 3 shows a schematic diagram of a processing flow by the conversion means 223.

  Hereinafter, an image processing method performed using the printer 20 will be described with reference to a flowchart shown in FIG. The following processing is mainly executed by the CPU 201. In addition, each process (including the partial process to which the code | symbol is not provided) can be arbitrarily changed in order within the range which does not produce contradiction in the processing content, or can be performed in parallel. The CPU 201 has various functions, but descriptions of functions not directly related to image processing are omitted.

  In the present embodiment, the printer 20 stores the first conversion information and the second conversion information described above in advance in the first storage unit 224 and the second storage unit 225, respectively, as a pre-stage of color conversion processing. To do.

  In the color conversion process in the printer 20, first, the printer controller 22 receives input data expressed in the input color space (step S100). For example, input data expressed in the “RGB” color space, input data expressed in the “RGB (2)” color space, or input data expressed in the “CMYK (2)” color space is received from the host computer 10. To do.

  Next, the printer controller 22 determines whether the input color space of the received input data is the second color space or the first color space (step S101).

  As a result of the determination, if the input color space of the input data is the first color space (step S101: first color space), the printer controller 22 converts the first conversion information corresponding to the first color space to the first color space. Obtained from the storage unit 224 (step S102). For example, if the received input data is input data expressed in the “RGB (2)” color space, the LUT “RGB (2) to RGB LUT” corresponding to the “RGB (2)” color space is the first. 1 from the storage unit 224.

  Next, the printer controller 22 converts the input data using the acquired first conversion information (step S103). For example, by using the LUT “RGB (2) to RGB LUT”, the input data is converted to the color value of the “RGB” color space in which the color value of the “RGB (2)” color space is the second color space. To do.

  Next, the printer controller 22 acquires the second conversion information from the second storage unit 225 (step S104). That is, the LUT “RGB to CMYK LUT” is acquired from the second storage unit 225.

  Next, the printer controller 22 converts the converted input data into output data using the acquired second conversion information (step S105). That is, by using the LUT “RGB to CMYK LUT”, the color value of the “RGB” color space that is the second color space is changed to the color value of the “CMYK” color space that is the output color space. The input data converted by the process is converted into output data.

  On the other hand, as a result of the determination in step S101, if the input color space of the input data is the second color space (step S101: second color space), the printer controller 22 stores the second conversion information in the second storage. Obtained from the unit 225 (step S106). For example, if the received input data is input data expressed in the “RGB” color space, the LUT “RGB to CMYK LUT” is acquired from the second storage unit 225.

  Next, the printer controller 22 converts the input data into output data using the acquired second conversion information (step S107). That is, by using the LUT “RGB to CMYK LUT”, the color value of the “RGB” color space is changed to the color value of the “CMYK” color space, and the input data is converted into output data.

  As described above, according to the image processing apparatus and the image processing method of the present embodiment, among the LUTs to be held in the printer 20, the LUT related to the output color space depending on the printer model is “RGB to CMYK LUT”. As a result, the only LUT to be changed depending on the printer model is the above LUT, the number of LUTs required for designing each printer model can be suppressed, and the labor and time of the designer associated with the LUT design can be greatly reduced. Can do.

  In other words, the LUT for converting to the output color space must be created taking into account the characteristics of the printer, which is troublesome for the designer. Conventionally, this LUT has to be created by the number corresponding to the type of the color space of the input data, which is an excessive burden on the designer. However, according to the present invention, since only one LUT can be created in consideration of the characteristics of the printer, it is possible to greatly reduce the time and effort of the designer associated with the LUT design.

  In addition, since the output color space used in the printer is generally a four-dimensional CMYK color space that depends on the printer model, the amount of data in each LUT that is converted into the four-dimensional output color space increases. . Therefore, when a plurality of LUTs to be converted into a four-dimensional output color space are held as in the prior art, the printer needs a large storage capacity. However, according to the present invention, by preparing an LUT for converting the color space of the input data to the second color space independent of the printer model, only one LUT for converting to the four-dimensional output color space can be obtained. Since the LUT that changes the color value of each input color space to the color value of the second color space can be roughly created without considering the characteristics of the printer, the storage capacity of the printer required to hold the LUT Can be reduced.

  Furthermore, in the present invention, the RGB color space is used as the second color space. When the second color space is used, if the color expressed in the CMYK color space cannot be expressed in the second color space, there is a problem that the original printing ability of the printer cannot be sufficiently exhibited. When the color expressed in the color space cannot be expressed in the CMYK color space, there is a problem in that the accuracy of color conversion is reduced when color conversion processing is performed on input data to output data. However, in the present invention, this problem can be solved by using the above-described RGB color space.

<Modification of First Embodiment>
In the image processing system 1 of the first embodiment, the case where the first storage unit 224 is arranged in the printer 20 has been described. However, the present embodiment is not limited to this, and for example, a device unit to which the printer 20 can be attached and detached. 5, the first storage unit 224 ′ may be disposed in the device unit 30 as shown in FIGS. 5 and 6. That is, when the input color space of the input data is the first color space, the conversion unit 223 accesses the device unit 30 attached to the printer 20 and corresponds to the first color space from the device unit 30. First conversion information is acquired. The device unit 30 can use, for example, a general printer board that executes each process of the printer, or a storage device such as a USB memory.

  Further, the first storage unit may be provided in each of the printer 20 and the device unit 30 (first storage units 224 and 224 ′), and different first conversion information may be stored. For example, the first storage unit 224 in the printer 20 stores “RGB (2) to RGB LUT”, “CMYK (2) to RGB LUT”, and “CMYK (3) to RGB LUT”. 30 may store “Lab to RGB LUT”.

  With these configurations, even when the LUT for converting the input data expressed in the input color space in the printer 20 itself is not stored, the device unit 30 storing the LUT is only mounted on the printer 20. Thus, the input data can be converted into output data.

  Further, in addition to the configuration of the printer controller 22 of the first embodiment, an update unit is provided, and the first conversion information held in the storage unit 224 ′ of the device unit 30 attached to the printer 20 is updated by the update unit. A configuration may be adopted in which the first storage unit 224 is added / updated.

Second Embodiment
The image processing system 2 according to the second embodiment is characterized in that the printer 20a includes a system A and a system B that execute color conversion processing.

  FIG. 7 is a block diagram illustrating a hardware configuration of the image processing system 2 of the present embodiment. The image processing system 1 includes a host computer 10a and a printer 20a.

  The host computer 10a includes a printer driver 101A and a printer driver 101B that make a print request to the printer 20a, and is a host device of the printer 20a. The printer driver 101A and the printer driver 101B function as system A and system B drivers for the printer 20a, respectively. The printer driver 101A generates input data such as an image expressed in a commonly used RGB color space, and transmits the input data to the printer 20a. The printer driver 101B uses an RGB (2) color space (a color space different from the RGB color space), a CMYK (2) color space, and a CMYK (3) color space (a color space different from the CMYK color space as an output color space). ) And the Lab color space, input data expressed in one of the color spaces is generated and transmitted to the printer 20a. Since the functions of the printer drivers 101A and 101B can be basically the same as the functions of the printer driver used in the normal printer 20, detailed description thereof will be omitted.

  The printer 20a includes a printer engine 21, a system A printer controller 22A, and a system B printer controller 22B. However, the system printer controller 22B can be configured separately from the printer 20a.

  Since the printer engine 21 and the system A printer controllers 22A and 22B can have the same hardware configuration as the printer engine 21 and the printer controller 22 of the first embodiment, a detailed description thereof will be omitted.

  As shown in FIG. 8, the system A printer controller 22A includes a receiving unit 221A, a converting unit 223A, and a second storage unit 225. The system B printer controller 22B includes a receiving unit 221B and a converting unit. Means 223B and a first storage unit 224 are provided.

  The first conversion information (LUT) stored in each of the first storage unit 224 and the second storage unit 225 is the same as that in the first embodiment. For example, the first storage unit 224 stores the first conversion information (LUT) from the first color space. Each LUT “RGB (2) to RGB LUT”, “CMYK (2) to RGB LUT”, “CMYK (3) to RGB LUT”, and “Lab to RGB LUT” to be converted into the output color space are stored. The 2 storage unit 225 stores an LUT “RGB to CMYK LUT” for converting from the second color space to the output color space.

  The receiving unit 221A receives input data expressed in the second color space (RGB color space) from the printer driver 101A in the host computer 10a. The receiving unit 221B receives any one of the first color space (RGB (2) color space, CMYK (2) color space, CMYK (3) color space, and Lab color space) from the printer driver 101B in the host computer 10a. ) Is received.

  When the receiving unit 221A receives the input data, the converting unit 223A acquires the second conversion information from the second storage unit 225, and converts the received input data into output data using the acquired second conversion information. . When the receiving unit 221B receives the input data, the conversion unit 223B acquires the second conversion information from the second storage unit 225 of the system A printer driver, and acquires the first conversion information from the first storage unit 224. Then, the received input data is converted into output data using the acquired first conversion information and second conversion information. FIG. 10 shows a schematic diagram of a processing flow by the conversion unit 223A and the conversion unit 223B.

  That is, as shown in FIG. 9, the system A printer controller 22A receives the input data expressed in the RGB color space and outputs the received input data using the “RGB to CMYK LUT” held by itself. Conversion to output data expressed in the CMYK color space, which is a color space, is completed, and the color conversion processing is terminated. On the other hand, the system B printer controller 22B receives input data expressed in various input color spaces (first color space). Here, it is necessary to convert the input color space of the received input data into the CMYK color space that is the output color space. The printer controller 22B for the system B cooperates with the printer controller 22A for the system A in the conversion process. Do it. More specifically, each of the LUTs “RGB (2) to RGB LUT”, “CMYK (2) to RGB LUT”, “CMYK (3) to RGB LUT”, and “Lab to RGB LUT” held by itself The conversion process is executed using the LUT “RGB to CMYK LUT” held by the system A printer controller 22A.

  Hereinafter, an example of a processing procedure when the system B is activated will be described with reference to the flowchart shown in FIG. The following processing is mainly executed by the CPU 201B. In addition, each process (including the partial process to which the code | symbol is not provided) can be arbitrarily changed in order within the range which does not produce contradiction in the processing content, or can be performed in parallel. The CPU 201B has various functions, but descriptions of functions that are not directly related to image processing are omitted.

  First, the printer controller 22B receives input data expressed in the first color space (step S200). For example, input data expressed in the “RGB (2)” color space and input data expressed in the “CMYK (2)” color space are received from the host computer 10.

  Next, the printer controller 22B acquires first conversion information corresponding to the first color space of the received input data from the first storage unit 224 (step S201). For example, if the received input data is input data expressed in the “RGB (2)” color space, the LUT “RGB (2) to RGB LUT” corresponding to the “RGB (2)” color space is the first. 1 from the storage unit 224.

  Next, the printer controller 22B converts the input data using the acquired first conversion information (step S202). For example, by using the LUT “RGB (2) to RGB LUT”, the color data of the “RGB (2)” color space is converted to the color value of the “RGB” color space, and the input data is converted.

  Next, the printer controller 22B acquires second conversion information (LUT) from the second storage unit 225 of the system A (step S203). That is, the LUT “RGB to CMYK LUT” is acquired from the second storage unit 225.

  Next, the printer controller 22B converts the converted input data into output data using the acquired second conversion information (step S204). That is, by using the LUT “RGB to CMYK LUT”, the color value of the “RGB” color space that is the second color space is changed to the color value of the “CMYK” color space that is the output color space, and the process of step S202 above is performed. The input data converted in step 1 is further converted into output data.

  In place of the processing in steps S203 to S204, the printer controller 22B transmits data expressed in the “RGB” color space to the printer controller 22A, and the printer controller 22A that has received this data stores the LUT “ Using “RGB to CMYK LUT”, the color value of the “RGB” color space can be changed to the color value of the “CMYK” color space, and the input data converted in the process of step S202 can be converted into output data.

  As described above, according to the image processing apparatus and the image processing method of the second embodiment of the present invention, the system B side does not hold the LUT for CMYK depending on the model of the printer 20, and the LUT is not stored on the system A side. Use what is retained. As a result, since the LUT held by the system B printer controller 22B does not depend on the printer model, it can be used for any printer model in that sense. It can be used as it is. If the controller part is composed of a detachable board, the system B printer controller 22B is used as it is on another printer capable of using the systems A and B such as the printer 20a. can do.

<Modification>
The preferred embodiments of the present invention have been described above. However, the present invention should not be limited to the above embodiments, and does not depart from the spirit and scope expressed in the claims. Various modifications, additions, and omissions are possible by those skilled in the art.

  For example, in each of the above embodiments, the case where each conversion process is performed using each LUT from the first storage unit 224 and the second storage unit 225 has been described. However, the present invention is not limited to this, and after each LUT is synthesized One conversion process may be performed. For example, in the image processing system 1 of the first embodiment, when input data expressed in the RGB (2) color space is received, the LUT “RGB (2) to RGB LUT” is acquired from the first storage unit 224. Further, the LUT “RGB to CMYK LUT” is acquired from the second storage unit 225, and a composite LUT “RGB (2) to CMYK LUT” is created from these LUTs, and RGB (2) is created using the created LUT. Input data expressed in a color space can be converted into output data expressed in CMYK.

  In each of the above embodiments, four color spaces of RGB (2), CMYK (2), CMYK (3), and Lab have been described as examples of the first color space. However, the present invention is not limited thereto. Instead, the first color space can be at least one color space different from the second color space.

  Further, in each of the above embodiments, the case where the printer 20 has a function as an image processing apparatus has been described. However, the present invention is not limited to this. For example, the function of the image processing apparatus is incorporated in the host computer 10 to Each function of the image processing apparatus can also be realized by the control unit. Further, the printer 20 is not limited to receiving input data from the host computer 10, and may be configured to receive input data from an image forming apparatus such as a scanner device, for example.

  Further, in each of the embodiments described above, the printer 20 as the image processing apparatus is provided with each unit according to the application. However, each unit provided in the printer 20 is configured by collecting some of them. Alternatively, one unit may be further divided into a plurality of units.

  DESCRIPTION OF SYMBOLS 1 Image processing system, 10 Host computer, 101 Printer driver, 20 Printer, 21 Printer engine, 22 Printer controller, 221 Reception means, 222 Judgment means, 223 Conversion means, 224 1st memory | storage part, 225 2nd memory | storage part, 30 apparatus unit.

Claims (5)

An image processing apparatus that converts input data expressed in an input color space into output data expressed in an output color space,
A first storage unit that stores first conversion information for converting the first color space into the second color space;
A second storage unit that stores second conversion information for converting the second color space into the output color space;
Conversion means for converting the input data into output data using the second conversion information when the input color space of the input data is the second color space;
With
When the input color space of the input data is the first color space, the conversion means converts the input data into output data using the first conversion information and the second conversion information.   The image processing apparatus according to claim 1, wherein the first storage unit stores a plurality of the first conversion information according to a type of the first color space. The image processing apparatus includes a detachable device unit,
The image processing apparatus according to claim 1, wherein the first storage unit is disposed in the device unit. An image processing method for converting input data expressed in an input color space into output data expressed in an output color space,
Storing first conversion information for converting the first color space into the second color space, and second conversion information for converting the second color space into the output color space;
When the input color space of the input data is the second color space, the input data is converted into output data using the second conversion information;
When the input color space of the input data is the first color space, the input data is converted into output data using the first conversion information and the second conversion information.   An image processing program for causing a computer to execute the image processing method according to claim 4.

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