JP2009290719A - Image processor, image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the image processor and the image processing program capable of reproducing an original color exactly. <P>SOLUTION: The image processor includes a memory means, an acquisition means, a first correction means, and a second correction means. The memory means stores an image information showing an image expressed in at least one criterion color among a plurality of criterion colors. The acquisition means acquires an image related information indicative of whether an image expressed with the image information stored at the memory means is expressed or not with a plurality of criterion colors which can adjust gray balance. When the image related information acquired by the acquisition means indicates that the image is expressed with the plurality of criterion colors which can adjust gray balance, the first correction means corrects the image information so that the gray balance may become proper. The second correction means corrects the image information so that the tone of criterion colors showing the image may be corrected for every color. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In general, a printer has a calibration function in order to compensate for a color variation caused by a change in printing characteristics of the printer with time. Two methods are known as calibration methods.

  The first method corrects CMYK components independently using a one-dimensional table, and the second method maps CMY3 components to CMY3 components according to the current printer characteristics using a three-dimensional table. Is. The second method described above is a method that mainly focuses on improving the gray balance of process black using three colors of CMY.

  Of these two methods, the first method is generally widespread, and this method is also called TRC correction (Tone Reproduction Curve).

Patent Document 1 discloses a technique for performing color correction separately for a K component and a CMY component.
JP 2007-89031 A

  In this technical background, drawing objects constituting a document to be printed are mainly classified into characters, graphics, and images. Characters and graphics are “pure colors” such as RGB and CMYK (primary colors and secondary colors). Often expressed in colors. On the other hand, an image is often a natural picture composed of tertiary colors.

  The first method corrects the gradation characteristics of the primary color so that no other color is mixed into the “pure color”, but the gray balance of the natural image cannot always be corrected.

  On the other hand, the second method is the opposite, and it is effective for correcting gray balance. However, when “pure color” is calibrated, other colors may be mixed (for example, calibration is performed even though the color is originally Y only). C and M are mixed in by doing this).

  Furthermore, some images may be generated using a graphics function and eventually expressed as an image. In this case, since the image is a special image, it is more than “gray balance correction”. “Pure color” reproduction is preferred, and when the second method is applied, mixing of other inks becomes a problem.

  As described above, there is a problem in that the original color cannot be accurately reproduced, for example, by mixing other colors not included in the original image by performing the correction described above.

  In view of the above problems, an object of the present invention is to provide an image processing apparatus and an image processing program capable of accurately reproducing the original color.

  In order to achieve the above object, the invention of claim 1 is characterized in that storage means storing image information representing an image expressed by at least one reference color of a plurality of reference colors, and an image stored in the storage means. An acquisition unit that acquires image-related information indicating whether an image represented by information is represented by a plurality of reference colors that can be adjusted in gray balance; and the image-related information acquired by the acquisition unit includes a gray balance A first correction unit that corrects the image information so that the gray balance is appropriate and a reference color that represents the image when the image is represented by a plurality of reference colors that can be adjusted; And second correction means for correcting the image information so that the gray level of the image is corrected for each color.

  In the invention of claim 2, in the invention of claim 1, the image related information is an image type in which an image represented by the image information is represented by an image, or a character type other than that. And at least one of color number information indicating the number of reference colors representing the image, and the first correction unit includes the case where the type information indicates an image type, and When the information represents the number of gray balances that can be adjusted, the image information is corrected so that the gray balance is appropriate.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, an input for inputting correction application information indicating whether or not the correction by the first correction unit is applied to the image information. The first correction means performs correction when the correction application information indicates that the correction is applied to the image information.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the reference colors are cyan, magenta, and yellow, or cyan, magenta, yellow, and black.

  In order to achieve the above object, the invention according to claim 5 is characterized in that an image represented by image information representing an image represented by at least one reference color of a plurality of reference colors is a plurality of references whose gray balance can be adjusted. Acquisition means for acquiring image-related information indicating whether the image is represented by color, and the image-related information acquired by the acquisition means, wherein the image is represented by a plurality of reference colors whose gray balance can be adjusted. A first correction unit that corrects the image information so that the gray balance is appropriate, and the image information so that the gradation of the reference color representing the image is corrected for each color. It is an image processing program for functioning as a second correcting means for correcting.

  In order to achieve the above object, an invention according to claim 6 is an image processing program for causing a computer to function as each means constituting the image processing apparatus according to any one of claims 1 to 4. .

  According to the first aspect of the present invention, when the image is represented by a plurality of reference colors whose gray balance can be adjusted, the image information is corrected so that the gray balance is appropriate. In the case where the gray balance can be corrected by the above and the image is not represented by a plurality of reference colors whose gray balance can be adjusted, the correction is not performed by the first correction means. As a result of avoiding the mixing, it is possible to provide an image processing apparatus capable of accurately reproducing the original color.

  According to the second aspect of the present invention, it is possible to perform correction based on the image related information obtained from the image information, and therefore it is possible to provide an image processing apparatus that can accurately reproduce the original color. it can.

  According to the invention of claim 3, by further including the input means, the user can select whether or not to apply the first correction means to the image information.

  According to the invention of claim 4, examples of the reference color include cyan, magenta, and yellow, or cyan, magenta, yellow, and black.

  According to the fifth aspect of the present invention, when the image is represented by a plurality of reference colors whose gray balance can be adjusted, the image information is corrected so that the gray balance is appropriate. In the case where the gray balance can be corrected by the above and the image is not represented by a plurality of reference colors whose gray balance can be adjusted, the correction is not performed by the first correction means. As a result of avoiding mixing, it is possible to provide an image processing program that makes it possible to accurately reproduce the original color.

  According to the sixth aspect of the present invention, when the image is represented by a plurality of reference colors whose gray balance can be adjusted, the image information is corrected so that the gray balance is appropriate. In the case where the gray balance can be corrected by the above and the image is not represented by a plurality of reference colors whose gray balance can be adjusted, the correction is not performed by the first correction means. As a result of avoiding mixing, it is possible to provide an image processing program that makes it possible to accurately reproduce the original color.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a printer is used as an example of the image processing apparatus. The reference colors CMYK used in the following description indicate cyan, magenta, yellow, and key color, respectively.

  FIG. 1 shows the hardware configuration of the printer 10. The printer 10 includes a central processing unit (CPU) 40, a flash memory 42, a random access memory (RAM) 44, a non-volatile memory (NVM) 46, a user interface (UI) 48, and a hard disk drive (HDD). ) 50, printer engine 52, scanner engine 54, communication I / F (interface) 56, and bus 60.

  The CPU 40 governs the overall operation of the printer 10, and the processing shown in the flowchart described later is executed by the CPU 40. The flash memory 42 stores a program developed in the RAM 44, a boot program that operates at the time of startup, and the like.

  The RAM 44 is a storage device in which an OS (Operating System), programs, image information, and the like are expanded. The NVM 46 stores setting values and the like related to the printer 10. The UI 48 is used when the user inputs operations of the printer 10 and information. The HDD 50 is a storage device that stores image information and the like.

  The printer engine 52 is an engine that prints an image on a recording medium such as paper. The scanner engine 54 reads an image drawn on a document and generates image information indicating the read image.

  The communication I / F 56 includes a NIC (Network Interface Card) for connecting to a network, its driver, a USB device, and the like. The bus 60 is used when information is exchanged.

  In addition, you may make it add the interface regarding a telephone line, and the thing regarding image processing to the structure demonstrated above.

  The HDD 50 described above stores an image processing program (to be described later) executed by the CPU 40 and data used by the program. This program is not necessarily a program recorded in the HDD 50. Specific examples of the recording medium other than the HDD 50 include a program recorded on a portable recording medium. In this case, the printer 10 is provided with a reading device for reading a portable recording medium, and the portable recording medium causes a change state of energy such as magnetism, light, electricity, etc. to the reading device, and responds to it. The contents of the program description can be transmitted to the reading device in the form of a signal.

  Examples of portable recording media include magneto-optical disks, optical disks (including CDs and DVDs), magnetic disks, memories (including IC cards and memory cards), and the like.

  Next, a software configuration for executing image processing according to the present embodiment will be described with reference to FIG.

  FIG. 2 shows a PDL (Page Description Language) parser 20, a color conversion unit 22, a CMY correction unit 24, a KCMY correction unit 26, a screen processing unit 28, a CMY correction application control unit 30, and the UI 48.

  The PDL parser 20 generates image information (information indicated by RGB (Red Green Blue) or CMYK) indicating an image based on information described in PDL stored in the HDD 50.

  At this time, image-related information indicating whether the gray balance is represented by a plurality of reference colors that can be adjusted is acquired. Specifically, type information indicating that the image represented by the image information stored in the HDD 50 is an image type represented by an image or a character type other than that, and a reference color representing the image The image related information including at least one of the color number information indicating the number of the image is acquired. This image related information is notified to the CMY correction application control unit 30.

  The color conversion unit 22 further converts the image information into image information having a standard dot ratio. When the image information is image information with a standard halftone dot ratio, the color conversion unit 22 is not necessary.

  The CMY correction application control unit 30 determines whether the image-related information indicates that the image is represented by a plurality of reference colors whose gray balance can be adjusted. The determination result is a CMY correction unit. 24 is notified.

  The CMY correction unit 24 (first correction unit) corrects the CMY components included in the pixels constituting the image information when the CMY correction application control unit 30 makes a positive determination. At this time, correction is performed from CMY to CMK using a three-dimensional LUT (Look Up Table) stored in advance in the HDD 50. The CMY correction unit 24 performs gray balance adjustment of process black.

  The KCMY correction unit 26 (second correction unit) corrects the CMYK components included in the pixels constituting the image information for each color. At this time, each correction is made from CMYK to CMYK using a one-dimensional LUT stored in advance in the HDD 50. The KCMY correction unit 26 corrects the image information so that the gradation of the reference color representing the image is corrected for each color.

  Thus, the CMY correction unit 24 is a three-dimensional mapping from CMY to CMY, and the KCMY correction unit 26 has four one-dimensional mappings from C to C, M to M, Y to Y, and K to K. Is. Therefore, in the correction by the CMY correction unit 24, for example, a pixel that is a CM component may be converted into a pixel of a CMY component.

  The image information having the corrected halftone dot ratio is generated by these two correction units, and the screen processing unit 28 performs screen processing on the image information and outputs a page image used for printing. .

  The UI 32 is used by the user to input correction application information indicating whether to correct image information using the CMY correction unit 24. The correction application information input here is notified to the CMY correction application control unit 30.

  Hereinafter, the flow of image processing will be described using a flowchart. In the following description, correction by the CMY correction unit 24 is referred to as 3D correction, and correction by the KCMY correction unit 26 is described as 1D correction. Further, the following processing is executed by the CPU 40.

  First, image processing (part 1) will be described with reference to FIG. First, in step 101, type information is acquired. In the next step 102, if the type indicated by the type information is an image type, 3D correction is performed in step 103, 1D correction is performed in step 104, and the process ends. On the other hand, if a negative determination is made in step 102, 1D correction is performed in step 104, and the process ends.

  This image processing (part 1) is processing that indicates that 3D correction is performed for the image type because gray balance adjustment by 3D correction is unnecessary when the type of image is a character type.

  Next, image processing (part 2) will be described with reference to FIG. First, in step 201, color number information is acquired. In the next step 202, if the number-of-colors information indicates that the number of reference colors is 3 or more, 3D correction is performed in step 203, 1D correction is performed in step 204, and the process is terminated. On the other hand, if a negative determination is made in step 202, 1D correction is performed in step 204 and the process is terminated.

  In this image processing (part 2), when the number of colors information indicates that the number of reference colors is 2 or less, gray balance adjustment by 3D correction is unnecessary, and therefore, when the number of reference colors indicates 3 or more. This is processing that indicates that 3D correction is performed. Here, the number of reference colors indicates the number of CMY and is used in this sense in the following description.

  Next, image processing (part 3) will be described with reference to FIG. First, in step 301, type information and color number information are acquired. In the next step 302, if the type indicated by the type information is an image type and the color number information indicates that the number of reference colors is 3 or more, 3D correction is performed in step 303, 1D correction is performed in step 304, and the process ends. To do. On the other hand, if a negative determination is made in step 302, 1D correction is performed in step 304, and the process ends.

  In this image processing (part 3), when the number of color information indicates that the number of types of reference colors is 2 or less, or when the type is other than the image type, gray balance adjustment by 3D correction is not necessary. This is a process indicating that 3D correction is performed when the color is 3 or more and the type is an image type.

  Since the image processing Nos. 1 to 3 described above are not related to input by the user, the UI 48 shown in FIG. 2 is unnecessary.

  Next, image processing (part 4) will be described with reference to FIG. First, in step 401, correction application information is acquired. Here, the type information and the color number information may or may not be acquired. Therefore, this process is a process depending on the correction application information regardless of the image related information. Therefore, notification of image related information is unnecessary.

  When the next step 402 indicates that the correction application information is set to apply 3D correction, 3D correction is performed in step 403, 1D correction is performed in step 404, and the process ends. On the other hand, if a negative determination is made in step 402, 1D correction is performed in step 404 and the process is terminated.

  This image processing (part 4) is processing indicating that 3D correction is unconditionally performed when the user desires 3D correction regardless of the type and the number of colors.

  Next, image processing (part 5) will be described with reference to FIG. First, in step 501, correction application information and type information are acquired. In the next step 502, when the type indicated by the type information is an image type and the correction application information is an image type, it is indicated that 3D correction is set to be applied. In step 503, 3D correction is performed. Then, 1D correction is performed and the process is terminated. On the other hand, if a negative determination is made in step 502, 1D correction is performed in step 504, and the process ends.

  This image processing (No. 5) is processing when the user desires 3D correction for the case where the type is image.

  Next, image processing (part 6) will be described with reference to FIG. First, in step 601, correction application information, type information, and color number information are acquired. In the next step 602, when the type indicated by the type information is an image type, the number of colors information indicates the number of reference colors is 3 or more, and the correction application information is an image type, 3D correction is applied. If it is determined that there is a difference, 3D correction is performed in step 603, 1D correction is performed in step 604, and the process is terminated. On the other hand, if a negative determination is made in step 602, 1D correction is performed in step 604, and the process ends.

  This image processing (No. 6) is processing when the user desires 3D correction for the case where the reference color is 3 or more and the type is the image type.

  The processing flow of each flowchart described above is an example, and the processing order may be changed, new steps may be added, or unnecessary steps may be deleted without departing from the scope of the present invention. Needless to say, you can.

FIG. 2 is a diagram illustrating a hardware configuration of a printer. It is a figure which shows the software structure for performing the image process which concerns on embodiment. It is a flowchart which shows the flow of a process of an image process (the 1). It is a flowchart which shows the flow of a process of image processing (the 2). It is a flowchart which shows the flow of a process of an image process (the 3). It is a flowchart which shows the flow of a process of an image process (the 4). It is a flowchart which shows the flow of a process of image processing (the 5). It is a flowchart which shows the flow of a process of an image process (the 6).

Explanation of symbols

10 Printer 20 PDL Parser 22 Color Conversion Unit 24 CMY Correction Unit 26 KCMY Correction Unit 28 Screen Processing Unit 30 CMY Correction Application Control Unit 40 CPU
48 UI
50 HDD

Claims (6)

Storage means for storing image information representing an image represented by at least one reference color of a plurality of reference colors;
Obtaining means for obtaining image-related information indicating whether the image represented by the image information stored in the storage means is represented by a plurality of reference colors whose gray balance can be adjusted;
When the image-related information acquired by the acquisition unit indicates that the image is represented by a plurality of reference colors whose gray balance can be adjusted, the image information is set so that the gray balance is appropriate. First correction means for correcting
Second correction means for correcting the image information so that the gradation of the reference color representing the image is corrected for each color;
An image processing apparatus. The image-related information includes type information indicating that the image represented by the image information is an image type represented by an image or a character type other than that, and the number of reference colors representing the image. Including at least one of the color number information shown,
When the first correction means indicates the image type, and when the color-specific information indicates the number by which the gray balance can be adjusted, the image is adjusted so that the gray balance is appropriate. The image processing apparatus according to claim 1, wherein the information is corrected. Input means for inputting correction application information indicating whether or not to apply the correction by the first correction means to the image information;
The image processing apparatus according to claim 1, wherein the first correction unit performs correction when the correction application information indicates that the correction is applied to the image information.   The image processing apparatus according to claim 1, wherein the reference colors are cyan, magenta, and yellow, or cyan, magenta, yellow, and black. Computer
Acquisition of image-related information indicating whether an image represented by image information representing an image represented by at least one reference color of a plurality of reference colors is represented by a plurality of reference colors whose gray balance can be adjusted Means,
When the image-related information acquired by the acquisition unit indicates that the image is represented by a plurality of reference colors whose gray balance can be adjusted, the image information is set so that the gray balance is appropriate. First correction means for correcting
Second correction means for correcting the image information so that the gradation of the reference color representing the image is corrected for each color;
Image processing program to make it function.   An image processing program for causing a computer to function as each means constituting the image processing apparatus according to any one of claims 1 to 4.

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