JP2006108773A - Image processor, and printing system and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of sufficiently expressing a preferred color and obtaining an image with excellent image quality. <P>SOLUTION: In the image processor 3 provided with a color conversion section 42 for converting first image data expressed in a first color space into second image data expressed in a second color space, the color conversion section 42 includes: a first color conversion section 45 for applying color correction to the first image data in the same color space as the first color space and generating the color correction data; and a second color conversion section 46 for selectively using at least one from among a plurality of color conversion tables LUTs on the basis of types of color corrections executed by the first color conversion section 45, applying color conversion to the color correction data from the first color space into the second color space and generating the second image data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus, a printing system, and a program. More specifically, the present invention relates to a technique for suitably executing image processing for color reproduction when converting a color space of image data.

  2. Description of the Related Art Conventionally, in an image processing apparatus provided in a printing system or the like, a printer (image forming apparatus) uses, for example, RGB color system data (hereinafter referred to as “RGB data”) input as image data using a predetermined color conversion table. A color conversion process for converting the data into possible color materials, that is, data in the CMYK color system (hereinafter, “CMYK data”) is performed. The CMYK data is converted into binary data in an expression format depending on whether or not each color dot is formed, and print data to be supplied to the printer is created.

By the way, in such an image processing apparatus, in order to obtain a color reproduction desired by the user, various color corrections corresponding to image characteristics are made to the RGB data in the process of converting the RGB data into CMYK data. By doing so, the printing image quality by the printer is improved. For example, processing such as correcting the color tone, correcting the lightness, expanding the contrast, and the like. As a prior art related to the configuration of an image processing apparatus that performs such color correction, for example, there is one disclosed in Patent Document 1.
Japanese Patent Laid-Open No. 2003-50001

  However, in the above conventional technique, even if color correction according to the color reproduction desired by the user is performed on the RGB data, the color correction data is converted into the CMYK data when the color correction is performed. Regardless of this, color conversion is performed using a common color conversion table. Therefore, there is a problem in that preferable colors cannot be expressed sufficiently, and color reproduction that should be originally obtained cannot be obtained suitably.

  The present invention has been made in view of these conventional situations, and an object of the present invention is to provide an image processing apparatus capable of sufficiently expressing a preferable color and thereby obtaining an image of good image quality. Another object is to provide a printing system and a program.

  In order to achieve the above object, according to the first aspect of the present invention, the first image data expressed in the first color space is expressed in a second color space different from the first color space. In the image processing apparatus including a color conversion unit that converts the image data into the second image data, the color conversion unit corrects the color of the first image data in the same color space as the first color space, and performs color correction data. A first color conversion unit for generating the color correction data, and at least one of a plurality of color conversion tables based on the type of the color correction performed by the first color conversion unit, and the color correction data And a second color conversion unit that generates the second image data by performing color conversion from the first color space to the second color space.

  According to this image processing apparatus, after the first image data is color-corrected in the same first color space, an optimum color conversion table is selected from the plurality of color conversion tables according to the type of color correction. The color correction data is used to convert the color correction data into the second image data. Thereby, it becomes possible to express a preferable color more fully.

  In the above-described image processing apparatus, the color correction performed by the first color conversion unit acquires a feature amount of the first image data from the first image data, and based on the feature amount, It is also possible to adopt an aspect such as automatic color correction for creating color correction data.

  According to this image processing apparatus, the color correction in the first color conversion unit is an automatic color correction for automatically determining the feature of the image, so that the quality of color reproduction can be further improved. When the process in the first color conversion unit is such an automatic color correction process, the subsequent process in the second color conversion unit inevitably also corresponds to the automatic color correction (color conversion process). It becomes. That is, in this configuration, when automatic color correction is performed on the first image data, color conversion to the second image data is performed using a color conversion table optimal for the automatic color correction. Thus, the automatic color correction process can be optimized.

  In the above-described image processing apparatus, the type of color correction performed by the first color conversion unit and the mapping stored in advance in association with the color conversion table to be used according to the type of color correction A mode in which the second color conversion unit selectively determines one of the plurality of color conversion tables from the plurality of color conversion tables according to the mapping table. Can also be adopted.

  According to this image processing apparatus, the color conversion table used by the second color conversion unit is uniquely determined according to the mapping table stored in advance in association with the type of color correction.

In the image processing apparatus described above, an aspect in which the second image data is CMYK data may be employed.
According to this image processing apparatus, the second color conversion unit creates CMYK data expressed in the color space of the color material used by the image forming apparatus as the second image data. The CMYK data is image data using the CMYK color system as a color space, and any combination of the color materials can be used. For example, CMYK data represented by four colors of CMYK or CMYK data represented by a combination of more colors may be used.

  In the second aspect of the present invention, the first image data expressed in the first color space is converted into second image data expressed in a second color space different from the first color space, In the printing system comprising: an image processing apparatus that creates print data from the second image data; and an image forming apparatus that performs printing based on the print data created by the image processing apparatus. The apparatus includes a first color conversion unit that generates color correction data by performing color correction on the first image data in the same color space as the first color space, and the first color conversion unit. Based on the type of color correction, at least one of a plurality of color conversion tables is selectively used, the color correction data is color-converted from the first color space to the second color space, and the first color conversion table is used. A second color conversion unit for generating image data of 2; It is summarized in that to obtain.

  According to this printing system, the image processing apparatus performs color correction on the first image data in the same first color space, and then selects an optimum color conversion table corresponding to the type of color correction from the plurality of color conversion tables. Is selected and converted from the color correction data to the second image data. Then, the print data created from the second image data is supplied to the image forming apparatus. Accordingly, it is possible to express a preferable color more sufficiently, and the print image quality can be improved.

  In a third aspect of the present invention, the first image data that is executed by the image processing device and expressed in the first color space is expressed in a second color space different from the first color space. The image processing apparatus converts the first image data in the same color space as the first color space to create color correction data. And at least one of a plurality of color conversion tables based on the type of color correction performed in the first step and the color correction data from the first color space. The gist of the present invention is a program for executing the second step of creating the second image data by performing color conversion to the second color space.

  According to this program, the image processing apparatus performs the first step and the second step, thereby performing a color conversion of the first image data into the second image data for preferable color reproduction. Can be suitably applied.

  In the above-described program, the image processing apparatus converts the second image data into binary data in an expression format based on the presence / absence of dot formation, and generates print data to be supplied to the image forming apparatus. It is also possible to adopt a mode in which the process can be further executed.

  According to this program, the image processing apparatus preferably executes the third step subsequent to the first step and the second step described above, so that the print data to be supplied to the image forming apparatus is suitably obtained. Can be created.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a printing system 1 according to the present embodiment. The printing system 1 includes an image input device 2, an image processing device 3, and an image forming device 4. The image input device 2 is configured by, for example, a scanner, a digital camera, a digital video camera, or the like. In the present embodiment, RGB (red, green, blue) gradation data is supplied to the image processing device 3 as image data D1. . The image processing apparatus 3 is configured by a computer system such as a personal computer, for example, and performs predetermined image processing on the input image data D1 and converts it into data to be supplied to the image forming apparatus 4. In the present embodiment, the image forming apparatus 4 is configured by a color ink jet printer, and the image processing apparatus 3 uses the image data D1 as print data PD supplied to the printer in a plurality of ink colors that can be used by the printer. The data is converted into binary data expressed by a combination, for example, CMYK (cyan, magenta, yellow, black).

  Although the printing system 1 according to the present embodiment is configured to include the image input device 2, printing is performed by the image processing device 3 and the image forming device 4 (printer) without including the image input device 2. The aspect by which the system 1 is comprised may be sufficient.

  Next, the system configuration of the image processing apparatus 3 will be described. The image processing apparatus 3 includes a CPU 11, a ROM 12, a RAM 13, a storage device 14, a display device 15, an operation device 16, an input I / F (interface) 17, and an output I. / F 18 and drive device 19, which are connected to each other via a bus 20.

  The ROM 12 stores programs and data for controlling the overall operation of the apparatus 3. The RAM 13 temporarily stores programs and data loaded from the storage device 14 and the drive device 19. The CPU 11 uses the programs and data stored and stored in the ROM 12 and RAM 13, and further controls the overall operation of the apparatus 3 while using the RAM 13 as a work area when performing various processes. . For example, the CPU 11 controls data communication with the image input device 2 and the image forming device 4 and controls image processing including color conversion processing described later.

  The storage device 14 stores an operating system (OS) (not shown) for controlling the entire apparatus 3 and an image processing program for realizing color conversion processing to be described later, and is read out to the RAM 13 as necessary. And executed by the CPU 11. Examples of the storage device 14 include an external storage device connected via a hard disk or a communication line.

  The display device 15 is composed of, for example, a CRT, an LCD, or the like, and is used for displaying a setting screen or displaying an image when setting printing conditions to be described later. That is, when an image is displayed on the display device 15 of the apparatus 3 based on the image data D1 input from the image input device 2, the display device 15 functions as an image forming device. In this case, the display device 15 requires RGB gradation data as an input. The operation device 16 is configured by, for example, a keyboard, a mouse, or the like, and is used for a request or instruction from a user, input of parameters, or the like.

  The input I / F 17 functions as an interface unit with the image input device 2 and outputs image data D1 from the device 2 to the RAM 13 and the storage device 14. The output I / F 18 functions as an interface unit with the image forming apparatus 4 (printer), and outputs the print data PD formed by the apparatus 3 to the printer.

  In the present embodiment, the program (image processing program) and data executed by the CPU 11 are provided on the recording medium 21, for example. The drive device 19 drives the recording medium 21 to access the recorded contents, reads out programs and data therefrom, and outputs them to the storage device 14. As the recording medium 21, an arbitrary recording medium such as an optical disk (CD-ROM, DVD-ROM,...), A magneto-optical disk (MO, MD,...) Can be used. The recording medium 21 includes a medium on which a program uploaded or downloaded via a communication medium is recorded, a disk device, and the like.

  FIG. 2 shows a functional configuration of the image processing apparatus 3. In the figure, the image forming apparatus 4 is shown as “printer 4”. In the following description, the image forming apparatus 4 is described as “printer 4” for convenience.

  The image processing apparatus 3 incorporates an application program (hereinafter “application”) 31 that operates under the OS. The OS of the image processing apparatus 3 also includes a printer driver program that functions as the printer driver 32 and a video driver program that functions as the video driver 33. The application 31 activates these driver programs. As a result, various processes for handling the image data D1 are performed. For example, the application 31 activates a printer driver program to generate print data PD to be supplied to the printer 4 from the image data D1, or activates a video driver program to display an image based on the image data D1 on the display device 15. To display.

  In such an image processing apparatus 3, an operation for starting a printing process or the like is performed using the operation apparatus 16. When the application 31 receives a print processing start instruction from the user through the operation device 16, the application 31 outputs the image data D1 stored in the RAM 13 or the storage device 14 to the printer driver 32 together with a necessary control command CMD. The printer driver 32 performs image processing including color conversion processing described later on the image data D1 to generate print data PD, and outputs the print data PD to the printer 4. The printer 4 performs printing based on the received print data PD.

Next, the functional configuration of the printer driver 32 will be described.
The printer driver 32 includes a resolution conversion unit 41, a color conversion unit 42, a binarization unit 43, and an MW (microweave) unit 44. Among these, the color conversion unit 42 includes a first color conversion unit 45 and a second color conversion unit 46 in the present embodiment.

  The resolution conversion unit 41 performs processing for converting the resolution of the image data D1 to a resolution (printing resolution) suitable for printing processing by the printer 4. For example, when the resolution of the image data D1 is lower than the printing resolution, the resolution conversion unit 41 creates new data between adjacent rasters of the image data D1 by performing linear interpolation. On the contrary, when the resolution of the image data D1 is higher than the printing resolution, the resolution conversion unit 41 converts the resolution of the image data D1 to a lower resolution by thinning out the data at a certain rate.

  In the present embodiment, the color conversion unit 42 uses image data (first image data, hereinafter referred to as “RGB data”) expressed in RGB (first color space) by the printer 4. Conversion to a plurality of possible ink colors, for example, image data expressed by CMYK (second color space) (second image data, hereinafter referred to as “CMYK data”) is performed.

  The color conversion process will be described in detail. In the present embodiment, the RGB data after the resolution conversion is first input to the first color conversion unit 45. The first color conversion unit 45 performs color correction on the RGB data with RGB in the same color space to create color correction data.

  Note that “color correction” means, for example, correcting the color tone, correcting the brightness, or enlarging the contrast according to the characteristics of the image in order to obtain a good quality image by reproducing a preferable color. This is a process for adding a correction such as. In the present embodiment, which of the color correction processes the first color conversion unit 45 performs is determined by the user confirming an image on the display device 15 and selecting a necessary process. It is determined by setting processing parameters.

  In this case, in the present embodiment, in order to automatically determine the feature of the image and perform color correction, the feature amount of the same image (RGB data) is acquired according to a predetermined evaluation criterion, and based on the acquired feature amount. The printer driver 32 is provided with a so-called automatic color correction function for performing color correction. That is, when such an automatic color correction function is selected by the user, the first color conversion unit 45 automatically determines the image characteristics according to the color reproduction purpose (color correction type) desired by the user. Then, color correction is performed. Such automatic color correction processing is executed based on an image processing program stored in the storage device 14 or the like. Note that there are a plurality of evaluation criteria for acquiring the feature amount of the image, and the feature amount of the image is evaluated according to the type of color correction (for example, emphasis on skin color correction or focus on contrast). Acquired according to standards.

  The RGB color correction data created in this way is then input to the second color converter 46. The second color conversion unit 46 performs color conversion for converting the RGB color correction data into a combination of a plurality of ink colors that can be used by the printer 4, in this embodiment, data expressed in CMYK. To create CMYK data.

  Here, in the present embodiment, a plurality of color conversion tables LUT1 to LUT4 are provided as reference tables for performing such color conversion, and the second color conversion unit 46 includes the first color conversion table 46 described above. Based on the type of color correction performed by the color conversion unit 45, color conversion is performed by selectively using any one of the plurality of color conversion tables LUT1 to LUT4. At this time, which of the plurality of tables LUT1 to LUT4 the second color conversion unit 46 uses is determined based on, for example, a mapping table MT (see FIG. 4) described later. That is, the second color conversion unit 46 uses the color conversion table optimized for the type of color correction applied to the color correction data generated by the first color conversion unit 45 to perform color conversion. Conversion is performed.

  As described above, in the present embodiment, in addition to the color correction in the same color space from RGB (input image data) to RGB (correction data) by the first color conversion unit 45, the color correction is further performed. Then, color conversion from RGB (color correction data) to CMYK (CMYK data) is performed by the second color conversion unit 46 using a color conversion table that is optimized according to the above. As a result, the reproduction of preferable colors is sufficiently performed, and the printing quality by the printer 4 is improved. The color conversion tables LUT (LUT1 to LUT4) and the mapping table MT are held as files in the RAM 13 and the storage device 14 described above.

  The binarizing unit 43 performs so-called halftone processing in which the CMYK data thus formed is converted into two-gradation image data (binary data) that can be expressed by the printer 4. That is, the CMYK data is data expressed by 256 gradations of each color, for example, gradation values 0 to 255, whereas the printer 4 has only one state in which dots are formed or dots are not formed. It cannot be taken. For this reason, it is necessary to convert such image data expressed by, for example, 256 gradations into binary data representing the presence / absence of dot formation, and the processing for converting the number of gradations is halftone processing.

  The MW unit 44 rearranges the image data (binary data) after such halftone processing in the order to be transferred to the printer 4 in consideration of the dot formation order in the printer 4, and uses it as print data PD. Form. That is, in the print head, since each nozzle is arranged in the paper feed direction at a nozzle pitch having a resolution lower than the print resolution, a continuous raster cannot be formed by one main scan. Therefore, in each main scan, a plurality of rasters are formed at nozzle pitch intervals, and each raster is gradually shifted to fill the space between the rasters each time a raster is formed. A raster is formed. The process of rearranging the dot data in the order to be transferred to the printer 4 in consideration of the number of nozzles, the nozzle pitch, and the like of the print head is called microweave processing. The print data PD formed by performing the microweave process includes data indicating the presence / absence of dot formation during each main scan, so-called raster data and data indicating the paper feed amount.

Next, the color conversion process performed by the printer driver 32 will be described with reference to FIG.
First, the color conversion mode is selected by the user based on the image displayed on the display device 15 (step 100). In the present embodiment, the color conversion mode can be set from, for example, three types of “without color correction”, “with color correction”, and “automatic color correction”.

  Here, “without color correction” is a mode that faithfully reproduces an image displayed on the display device 15 (hereinafter referred to as “first mode”), and “with color correction” is a color selected by the user. In this mode, color correction is performed according to the type of correction (target color reproduction) (hereinafter referred to as “second mode”). The “automatic color correction” is a mode (hereinafter referred to as “third mode”) in which the feature amount of the image is acquired as described above according to the type of color correction selected by the user, and color correction is performed based on the feature amount. It is said). As shown in FIG. 4, in this example, when the second mode is selected, either “natural hue” or “brilliant hue” can be selected as the type of color correction. When the third mode is selected, either “skin color correction emphasis” or “contrast emphasis” can be selected as the color correction type.

  When the color conversion mode is selected by the user in this manner, the printer driver 32 performs a mapping process for determining a color conversion table LUT to be used in the selected color conversion mode (step 110).

  This mapping process is performed with reference to a mapping table MT as shown in FIG. 4, for example. In the mapping table MT, the type of color correction performed by the first color conversion unit 45 (in other words, the type of color correction data generated from RGB data) and the color conversion used by the second color conversion unit 46 are displayed. The table LUT is stored in association with it. In this example, the color conversion table LUT1 is set for the first mode, and the color correction type (“natural hue”, “brilliant hue”) is set for the second mode. A common color conversion table LUT2 is set for each. Further, for the third mode, the color conversion table LUT3 is set corresponding to the color correction of “skin color correction emphasis” and the color conversion table LUT4 is set corresponding to the color correction of “contrast emphasis”. Yes. In this case, the common color conversion table LUT2 is set for each type of color correction for the second mode, but it may be set for each type of color correction.

  The printer driver 32 can uniquely determine the color conversion table LUT to be used according to the type of color correction to be performed, that is, the color reproduction purpose desired by the user, by referring to the mapping table MT. .

  Next, the printer driver 32 converts the resolution of the image data D1 received from the image input device 2 (via the application 31) and inputs the converted RGB data to the first color conversion unit 45 (step 120). ), Color correction processing is performed according to the color conversion mode selected by the user, and color correction data in the same color space is created (step 130).

  Next, the printer driver 32 inputs the RGB color correction data created by the color correction process to the second color conversion unit 46, and performs color conversion using the color conversion table LUT determined by the previous mapping process. Processing is performed (step 140), and the CMYK data created thereby is output from the second color conversion unit 46 (step 150).

  In the color conversion process in step 140, when the color correction performed by the first color conversion unit 45 is automatic color correction, the process by the second color conversion unit 46 is inevitably described above. The process corresponds to automatic color correction.

  In the image processing apparatus 3 configured as described above, as shown in FIG. 5, for example, when the first mode is selected, each color component (R, G, B) of the RGB data is the first. It is output as color correction data (R, G, B) as it is through the color converter 45. Then, using the color conversion table LUT1 corresponding to the (R, G, B) color correction data, the second color conversion unit 46 converts the color correction data into CMYK data of each color component (C, M, Y, K). .

When the second mode is selected, the color components (R, G, B) of the RGB data are corrected to (R ₁ , G ₁ , B ₁ ) by the first color conversion unit 45. Then, the _{(R 1, G 1, B} 1) of each color component by the second color conversion unit 46 using the color conversion table LUT2 corresponding to the color correction data _{(C 1, M 1, Y} 1, K 1) To CMYK data.

In the third mode, when the type of color correction is “important for skin color correction”, each color component (R, G, B) of the RGB data is converted to (R ₂ , G ₂ , B ₂ ) is corrected. Then, the (R _2, G _2, B ₂₎ of the color correction by the second color conversion unit 46 using the color conversion table LUT3 corresponding to the data of each color component _{(C 2, M 2, Y} 2, K 2) To CMYK data.

In the third mode, when the type of color correction is “contrast importance”, each color component (R, G, B) of RGB data is (R ₃ , G) by the first color conversion unit 45. ₃ is corrected to B _3). Then, the _{(R 3, G 3, B} 3) each color component by the second color conversion unit 46 using the color conversion table LUT4 corresponding to the color correction data _{(C 3, M 3, Y} 3, K 3) To CMYK data.

Thus, in this embodiment, the color reproduction quality can be improved by performing color conversion using the color conversion table LUT that is optimal for the type of color correction in each color conversion mode.
As described above, according to the present embodiment, the following effects can be obtained.

  (1) A first color conversion unit 45 that performs color correction on RGB data in the same color space to create color correction data, and a plurality of colors based on the type of color correction performed by the first color conversion unit 45 A color conversion table to be used is selected from the color conversion tables LUT1 to LUT4, and a color conversion data is converted to CMYK data using the selected color conversion table. Thereby, it becomes possible to express a preferable color more fully. That is, by creating print data PD based on the CMYK data created in this way and performing printing by the printer 4, an image with excellent print image quality can be obtained.

  (2) As the color correction performed by the first color conversion unit 45, automatic color correction is performed in which image feature amounts are acquired from RGB data according to a predetermined evaluation standard, and color correction data is created based on the feature amounts. It was possible. Thereby, the quality of color reproduction can be improved. When such an automatic color correction process is performed by the first color conversion unit 45, the subsequent process by the second color conversion unit 46 inevitably involves a process corresponding to the automatic color correction (color conversion process). ) That is, in the present embodiment, when automatic color correction is performed on RGB data, automatic color correction is performed by performing color conversion to CMYK data using a color conversion table optimal for the automatic color correction. The correction process can be optimized.

  (3) The color conversion table LUT used in the second color conversion unit 46 is determined according to the mapping table MT. By using such a mapping table MT, the color conversion table LUT to be used can be uniquely determined according to the type of color correction.

In the above-described embodiment, a modified example changed to the following mode may be adopted.
(Modification 1) In the above embodiment, printing is performed by the printing system 1 including the image processing apparatus 3 including the computer system and the printer 4 (image forming apparatus) connected thereto. May be used as a stand-alone machine, and printing may be performed by the printer 4 alone. In this case, the printer driver 32 may be constructed on the printer 4 side so that the function of the image processing apparatus 3 is shared by the printer 4. That is, the printer driver program is stored in, for example, the memory of the printer 4 and the CPU of the printer 4 executes the printer driver program (image processing including the color conversion processing described in the above embodiment). . In this way, even when printing is performed by the printer 4 alone, preferable color reproduction can be sufficiently performed to improve the print image quality. In short, the image processing apparatus according to the present invention can be realized by a computer system connected to the printer 4, and can also be realized by the printer 4 by providing the printer 4 with the function.

  (Modification 2) In the above embodiment, the color conversion table LUT used in the second color conversion unit 46 is determined by the mapping table MT, but may be determined without using such a table. .

  (Modification 3) In the above embodiment, the user selects the color conversion mode on the printer driver 32 (specifically, the type of color correction to be performed). Good. In this case, for example, a command CMD is transmitted from the application 31 based on the type of color correction received by the application 31, and the printer driver 32 selects a color conversion table LUT to be used based on the command CMD. do it.

  (Modification 4) In the above embodiment, the color conversion process is performed using any one color conversion table selected from the plurality of color conversion tables LUT1 to LUT4 based on the type of color correction. However, it is not necessarily limited to one. For example, depending on the type of color correction, color conversion processing may be performed using two or more of the plurality of color conversion tables LUT1 to LUT4.

  (Modification 5) In the above embodiment, the color conversion table LUT has four fixed types. However, a color conversion table LUT used in the second color conversion unit 46 is created based on the result of color correction. The color conversion to CMYK data may be performed based on the created color conversion table LUT.

(Modification 6) In the above embodiment, the color conversion table LUT has four types (LUT1 to LUT4). However, the present invention is not limited to four types.
(Modification 7) In the above embodiment, four colors C, M, Y, and K are used in the color conversion from RGB to CMYK. However, the present invention is not limited to these four colors.

(Modification 8) In the above embodiment, the first image data is RGB data. However, the first image data is not limited to RGB data, and may be image data in an expression format in other color spaces.
(Modification 9) In the above embodiment, in the aspect of the printing system 1 including the printer 4 (image forming apparatus), the second image data is CMYK data. The image data may be in the form of expression.

1 is a block diagram showing a schematic configuration of a printing system. FIG. 2 is a block diagram showing a functional configuration of the image processing apparatus. 6 is a flowchart illustrating color conversion processing executed by a printer driver. Explanatory drawing which shows an example of a mapping table. Explanatory drawing which shows the creation example of RGB color correction data and CMYK data.

Explanation of symbols

  1: printing system, 3: image processing apparatus, 4: printer as image forming apparatus, 32: printer driver, 42: color conversion unit, 45: first color conversion unit, 46: second color conversion unit, D1 : Image data, LUT (LUT1 to LUT4): Color conversion table, MT: Mapping table, PD: Print data.

Claims (7)

An image processing apparatus including a color conversion unit that converts first image data expressed in a first color space into second image data expressed in a second color space different from the first color space. ,
The color converter is
A first color conversion unit that creates color correction data obtained by color-correcting the first image data in the same color space as the first color space;
Based on the type of color correction performed by the first color conversion unit, at least one of a plurality of color conversion tables is selectively used, and the color correction data is transferred from the first color space to the second color conversion table. A second color conversion unit that performs color conversion into the color space to create the second image data;
An image processing apparatus comprising: The color correction performed by the first color conversion unit is an automatic color that obtains a feature amount of the first image data from the first image data and creates the color correction data based on the feature amount. Is a correction,
The image processing apparatus according to claim 1. A mapping table in which the type of color correction performed by the first color conversion unit and the color conversion table to be used according to the type of color correction are associated with each other and stored; The color conversion unit selectively determines one of the plurality of color conversion tables according to the mapping table as the color conversion table used in the color conversion.
The image processing apparatus according to claim 1 or 2. The second image data is CMYK data.
The image processing apparatus according to claim 1. The first image data expressed in the first color space is converted into second image data expressed in a second color space different from the first color space, and the print data is converted from the second image data. In a printing system formed by connecting an image processing apparatus that creates an image and an image forming apparatus that performs printing based on the print data created by the image processing apparatus,
The image processing apparatus includes:
A first color conversion unit that generates color correction data by performing color correction on the first image data in the same color space as the first color space;
Based on the type of color correction performed by the first color conversion unit, at least one of a plurality of color conversion tables is selectively used, and the color correction data is transferred from the first color space to the second color conversion table. A second color conversion unit that performs color conversion into the color space to create the second image data;
A printing system comprising: A program executed by an image processing device for converting first image data expressed in a first color space into second image data expressed in a second color space different from the first color space Because
The image processing apparatus is
A first step of creating color correction data by color-correcting the first image data in the same color space as the first color space;
Based on the type of color correction performed in the first step, at least one of a plurality of color conversion tables is selectively used, and the color correction data is transferred from the first color space to the second color. A second step of creating the second image data by color conversion to a space;
A program for running. The image processing apparatus can further execute a third step of generating print data to be supplied to the image forming apparatus by converting the second image data into binary data in an expression format based on the presence or absence of dot formation.
The program according to claim 6.

Images