JP2011148259A - Image processing apparatus and method, and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus and method, capable of using only a patch recorded less than maximum ink ejecting amount of recording media, among a plurality of patches. <P>SOLUTION: In a patch of which the ink ejecting amount for the recording media exceeds tolerance of the maximum ink ejecting amount set to the recording media among the plurality of patches, input image data of the patch is converted into different image data. Thus, it can be determined which patch is reliable among the plurality of patches. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing method, and an ink jet recording apparatus that perform color measurement on a patch recorded on a recording medium by an ink jet recording apparatus and perform image processing based on the result of the color measurement.

2. Description of the Related Art In recent years, an ink jet recording apparatus is known that includes a sensor that can perform colorimetry and includes a system that generates image processing parameters such as calibration and profile for enhancing color stability.
In an inkjet recording apparatus equipped with such a system, a user can create a profile for a recording medium prepared by the printer manufacturer as well as a recording medium prepared by the user and use it for recording.

  When the user creates a profile by himself as described above, a chart composed of color patches for colorimetry needs to be recorded on a recording medium. In order to record the chart, a tool for creating a profile provided by a third party is often used, and the color patch is recorded with a certain arrangement pattern defined by the tool. In addition, when a designer of a printer manufacturer designs various image processing parameters, a chart composed of various color patches is recorded, and the color is measured for designing. In many cases, the charts recorded here are basically color patches arranged in a fixed pattern.

  On the other hand, in an inkjet recording apparatus, there is a limit to the amount of ink that can be applied to a recording medium, and the limit varies depending on the type of recording medium, the recording mode, the type of ink, and the like. For example, even when recording is performed using the same ink jet recording apparatus, the maximum amount of ink that can be ejected (hereinafter referred to as the maximum allowable ink ejection amount) varies depending on the type of recording medium.

  For example, recording paper used for high-quality recording such as glossy paper has a large maximum allowable ink placement because the ink receiving layer is formed, and the maximum of recording paper such as plain paper that does not have an ink receiving layer formed. Ink placement capacity is small. If the amount of ink exceeding the maximum ink placement allowable amount is ejected without taking into consideration the maximum placement amount of such a recording medium, the ink overflows from the surface of the recording medium, stains the recording paper or the recording device, The paper may be deformed to cause a paper jam, which may cause a failure.

  On the other hand, the recording apparatus itself automatically limits the amount of ink used in order to prevent excessive ink from being applied to the recording medium and to prevent the apparatus from becoming dirty or damaged (hereinafter referred to as a limiter). Has also been proposed.

However, the conventional limiter records not only on a normal image but also on a chart for creating a profile. Therefore, even if a chart appears to have been recorded without any problem, when the color patch is actually measured, the relationship between the colorimetric value and the amount of ink that has been set for the color patch. However, it may deviate from the initially assumed relationship. For this reason, it is difficult to create an accurate profile based on the color measurement result of the color patch. In other words, the color patch that is not suitable for creating a profile and the color patch that is not activated by the limiter function is mixed in the chart. For this reason, it is difficult to determine which color patch in the chart the colorimetric value is reliable, and the limiter function prevents the creation of an appropriate profile.
As described above, although the conventional limiter function for the amount of shot is effective when recording a normal image, there is a problem that it is not suitable for recording a color patch for colorimetry.

  On the other hand, Patent Document 1 discloses a technique in which an electrophotographic image forming apparatus is provided with a mode for forming a normal image and a dedicated mode for forming a color patch. Here, when the usage amount of the color material exceeds the allowable amount in the normal image forming mode, the usage amount of the color material is limited, but in the color patch formation mode, the usage amount of the color material exceeds the allowable amount. However, it is possible to limit the amount of color material used. For this reason, according to the technique disclosed in Patent Document 1, it is possible to form a color patch suitable for creating a profile.

Japanese Patent Laid-Open No. 2004-021202

  However, since Patent Document 1 is a technique that assumes an image forming apparatus using an electrophotographic system, this technique cannot be applied to an ink jet recording apparatus that forms an image with ink. In other words, the ink jet recording apparatus has a problem that when excessive ink is applied to the recording medium, the ink overflows on the surface of the recording paper and the recording apparatus and the recording medium are contaminated as described above. Therefore, when the technique disclosed in Patent Document 1 that does not limit the amount of color material used in the color patch recording mode is employed, the above problem cannot be avoided.

  For the above reasons, in order to handle only reliable patch colorimetric data in the conventional ink jet recording apparatus, patch recording data is created every time according to the maximum ink ejection allowance of the recording medium. It is necessary to redo. In order to realize this, every time the type of the recording medium is changed, the user or the designer must re-create the patch print file, and the work becomes complicated accordingly. It is also conceivable that print files for a plurality of types of color patches with different driving amounts are created in advance and used selectively during recording. However, this causes a new problem that a large storage capacity must be allocated to store the print file.

  The present invention makes it possible to use only a patch recorded with a maximum ink ejection amount of the recording medium from a plurality of patches without changing the recording data of the patch every time the type of the recording medium is changed. An object of the present invention is to provide an image processing apparatus and an image processing method.

  Another object of the present invention is to provide an ink jet recording apparatus capable of forming a patch that allows a user or a colorimetric means to easily and reliably discriminate a patch formed with a maximum ink placement allowable amount or less. .

In order to achieve the above object, the present invention comprises the following arrangement.
That is, according to the first aspect of the present invention, an acquisition unit for acquiring input image data of each of a plurality of patches to be recorded on a recording medium by an ink jet recording apparatus, and ink placement on the recording medium of each of the plurality of patches A calculation unit that calculates the amount based on input image data of each of the plurality of patches, and a patch in which the ink ejection amount calculated by the calculation unit exceeds a maximum ink ejection allowable amount determined for the recording medium An image processing apparatus comprising: conversion means for converting image data to be converted into image data different from the input image data of the patch.

  According to a second aspect of the present invention, there is provided an acquisition step for acquiring input image data of each of a plurality of patches to be recorded on a recording medium by an ink jet recording apparatus, and an amount of ink applied to the recording medium of each of the plurality of patches. A calculation step of calculating based on input image data of each of the plurality of patches, and a patch in which the ink ejection amount calculated by the calculation step exceeds a maximum ink ejection allowable amount determined on the recording medium A conversion step for converting the image data into image data different from the input image data of the patch.

  According to a third aspect of the present invention, there is provided an inkjet recording apparatus capable of recording a plurality of patches constituting a chart for generating a parameter in image processing based on recording data of the patch, An acquisition unit for acquiring input image data of each of a plurality of patches to be recorded on a recording medium, and an ink placement amount for each of the plurality of patches based on the input image data of each of the plurality of patches A calculation means for calculating; and image data for recording a patch in which the ink ejection amount calculated by the calculation means exceeds a maximum ink ejection allowable amount determined for the recording medium; and the input image data of the patch Comprises conversion means for converting into different image data.

  According to the image processing apparatus and the image processing method of the present invention, even if the recording data of the patch is not changed every time the type of the ink jet recording medium is changed, the maximum ink ejection amount of the recording medium can be reduced from the plurality of patches. Only the recorded patch can be used.

  In addition, according to the ink jet recording apparatus of the present invention, it is possible to form a chart that allows a user or a colorimetric means to easily and reliably discriminate patches formed with a maximum ink placement allowable amount or less. .

1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment. FIG. 3 is a diagram conceptually illustrating a part of an image recorded on a recording medium by an ink jet recording apparatus. 1 is a diagram illustrating an embodiment of a system that performs colorimetry such as a color patch formed on a chart for setting image processing parameters recorded by an inkjet recording apparatus. It is a block diagram for demonstrating the inkjet recording system in this embodiment. It is a flowchart which shows the flow of the image processing in this embodiment. FIG. 6 is an explanatory diagram illustrating a method for correcting the ink ejection amount in the present embodiment. 6 is a flowchart illustrating an example of processing performed when a color patch is recorded in the present embodiment. It is a schematic diagram showing the example of the color patch in this embodiment. It is a flowchart which shows the flow which performs the process of the colorimetric value of the patch in this embodiment. It is explanatory drawing which shows an example of the method of setting an image processing parameter using only the reliable colorimetric value of the patch specified in this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic configuration of a serial type ink jet recording apparatus 100 used in the present embodiment. In the figure, reference numeral 1 denotes a recording head capable of discharging a plurality of colors of ink. The recording head 1 is detachably mounted on a carriage 2 that can move in the main scanning direction along a guide shaft 7.

  The carriage 2 is located at the home position before the start of recording. When the recording start command is received, the carriage 2 moves in the arrow X direction (main scanning direction). During this time, the recording head 1 mounted on the carriage 2 ejects ink toward the recording medium S at a predetermined timing. In the present embodiment, cyan (C), magenta (M), yellow (Y), and black (B) inks are ejected from a plurality of nozzle groups provided in the recording head 1.

  When a recording operation (hereinafter also referred to as recording scanning) performed by the recording head 1 during one movement of the carriage (hereinafter also referred to as scanning) is completed, the conveyance roller 3 rotates to move the recording medium S to the arrow. A predetermined amount is conveyed in the A direction. Thereafter, the recording head 1 performs recording in the direction of arrow C again. An image is formed on the recording medium S by repeating the recording scanning and the predetermined amount of conveying operation described above.

  The conveyance of the recording medium S during image formation is sandwiched between two roller pairs of a conveyance roller 3, a pinch roller 4 driven by the conveyance roller 3, and a discharge roller 5 and a spur 6 linked thereto. It is transported while being stretched on. When the image formation for one page is completed, the recording medium S is discharged out of the apparatus by the discharge roller 5.

  FIG. 2 is a diagram conceptually showing a part of an image recorded on the recording medium S by the ink jet recording apparatus 100 having the above configuration. In the ink jet recording apparatus according to the present embodiment, recording is performed on the pixels P arranged at a recording density of 1200 dpi as shown in FIG. In this specification, when ink droplets are ejected evenly to all the pixels in a predetermined unit area (for example, the region indicated by R in FIG. 2A) of the recording medium, the ink corresponding to the unit area is used. The driving amount is defined as 100%. Accordingly, when the ink dots are half-laid with a constant recording density with respect to the unit area, the ink placement amount is 50%, and the three color dots of C (cyan), M (magenta), and Y (yellow) are unit area. The state where the ink is evenly discharged is an ink ejection amount of 300%.

  FIG. 2B is a diagram showing the maximum allowable ink ejection amount for various recording media in accordance with the definition of the ink ejection amount as described above. As shown in the figure, the recording paper generally used for high-quality recording such as glossy paper has an ink receiving layer and therefore has a large maximum ink placement allowance, and an ink receiving layer such as plain paper is formed. The maximum ink placement capacity of unrecorded recording paper is small. For example, the maximum ink placement allowance for photo glossy paper is 240%, whereas the maximum ink placement allowance for plain paper is 180%. If an amount of ink exceeding the maximum ink placement allowable amount is discharged on any recording paper, the ink overflows from the surface of the recording paper, contaminates the recording paper or the recording device, or the recording paper is deformed and is jammed. This may cause a malfunction.

  FIG. 3 is a diagram showing an embodiment of a system that performs colorimetry such as a color patch formed on an image processing parameter setting chart (see FIG. 8B) recorded by the inkjet recording apparatus.

  In FIG. 3, reference numeral 300 denotes a host computer connected to the ink jet recording apparatus (hereinafter also simply referred to as a recording apparatus) 100. The host computer 300 includes a display device 311 such as a monitor, an input device 312 such as a keyboard 312a and a mouse 312b, an arithmetic processing device such as a CPU, a main device 301 including a storage device such as a ROM, a RAM, and a hard disk. Is provided. Reference numeral 302 denotes a spectral colorimetric device (hereinafter simply referred to as a colorimetric device). By applying a detection unit of this colorimetric device to a colorimetric object such as the recording medium S, a spectral spectrum of the colorimetric object can be obtained. it can. The colorimetric data indicating the spectral spectrum (colorimetric value) obtained here is sent to the main device 301 of the host computer 300. The host computer calculates Lab values, XYZ values, density values, and the like defined by the CIE in accordance with the colorimetric values from the spectral colorimetric device 302. Reference numeral 303 denotes a signal line for connecting the host computer 301 and the colorimetric device 302, and 304 is a signal line for connecting the host computer and the recording apparatus 100. Either of them can use a USB, a serial signal line, or the like.

  According to the system described above, it is possible to obtain the spectral spectrum of each patch of the chart recorded on the recording medium S, the ground color spectral spectrum of the recording medium S, and the like. In the system shown in FIG. 3, the color measurement device 302 is provided outside the recording device 100. However, a color measurement unit having the same function as the color measurement device 302 is provided inside the inkjet recording device 100. It can also be incorporated. In this case, it is possible to automatically perform a series of operations from recording to a recording medium to colorimetry.

  FIG. 4 is a block diagram for explaining an ink jet recording system including the ink jet recording apparatus 100 of the present embodiment and a main apparatus of a host computer 300 that is connected to the recording apparatus and performs main image processing. .

  A recording apparatus main control unit 401 controls the entire recording apparatus. The recording apparatus main control unit 401 includes an MPU, a ROM, a RAM, and the like. In this ROM or RAM, a limit value (maximum allowable ink ejection amount) of ink ejection amount for each recording medium is stored in advance. This may be determined according to the conventionally known maximum ink placement allowable amount of a recording medium, or may be configured by the user to set from the input device. In the present embodiment, it is assumed that the recording apparatus main control unit 401 controls the amount of ink to be applied to the recording medium. However, it is also possible to control the amount of ink to be ejected by another part, for example, a main device main control unit 408 described later.

  Reference numeral 407 denotes a system bus for communicating with each other, which will be described later, in the recording apparatus. Reference numeral 405 denotes a recording device interface (I / F) unit. The recording apparatus main control unit 401 receives data transmitted from the main apparatus main control unit 408 via the main apparatus interface (I / F) unit 409 via the recording apparatus I / F unit 405, and the received data Is temporarily stored in the data buffer 406. Thereafter, the recording apparatus main control unit 401 performs processing specific to the recording apparatus on the data stored in the data buffer 406. The processed data is accumulated in the recording buffer 402 as raster data for ejection by individual recording elements provided in the recording head 1.

  Reference numeral 404 denotes a paper supply / discharge motor control unit that feeds, conveys, and discharges the recording medium. Reference numeral 413 denotes a carriage motor control unit that performs control when the carriage 7 on which the recording head 4 is mounted is scanned in the main scanning direction. The recording apparatus main control unit 401 conveys the recording medium S by controlling the paper supply / discharge motor control unit 404 and controls the carriage motor control unit 413 to move the recording head 1 in the main scanning direction (X direction in FIG. 1). ). At this time, by further ejecting ink droplets from the recording head 1 according to the raster data for one row stored in the recording buffer 402, an image for one row is formed on the recording medium.

  On the other hand, reference numeral 408 denotes a main apparatus main control unit that controls each unit in the host computer 301. The main device main control unit 408 includes a CPU, a ROM, a RAM, and the like.

  In the ink jet recording system of the present embodiment, description will be made assuming that main image processing for an image to be recorded is performed by the recording apparatus main control unit 401. However, depending on the configuration of the recording system, image processing such as color conversion processing may be performed. This may be performed by the main device main control unit 408. Further, the image processing can be divided and performed by the recording apparatus main control unit 401 and the main apparatus main control unit 408.

  The main apparatus main control unit 408 transfers the image data processed in the main apparatus to the recording apparatus I / F unit 405 in the inkjet recording apparatus via the main apparatus I / F unit 409. In the inkjet recording system of this embodiment, a user interface is provided in the host computer 301.

  For this reason, the main device 408 has a display unit 410 for notifying the user of the type of recording method and the recording status, and for the user who has confirmed the display to set a recording mode or to input a recording start command. An operation unit 411 is provided. The display unit 410 may be any device that can display information, such as a CRT or a liquid crystal display, and the operation unit 411 may be any device that can input information, such as a keyboard 312a or a mouse 312b. good. Reference numeral 412 denotes a system bus for allowing each unit in the host computer 300 to communicate with each other.

  Reference numeral 414 denotes a color measuring device (color measuring means) provided in the ink jet recording apparatus 100. The color measuring device 414 can measure colors such as an image recorded on a recording medium, a color patch of a color measuring chart, or a ground color of the recording medium. Data indicating the value is transmitted to the recording apparatus main control unit 401. The color measuring device may be completely separated from the ink jet recording apparatus 100 as shown in FIG. 3, or may be incorporated in the recording apparatus 100. In the following, description will be made on the assumption that the color measuring device is built in the recording device.

  FIG. 5 shows an example of the flow of the image processing performed at 401 described above.

  When image data is input, first, color correction processing is performed on the input image data in S501. In this color correction processing, for example, when the input image data is data represented by RGB, correction by a lookup table (hereinafter referred to as LUT) is performed, and an image represented by R′G′B ′. Perform conversion to data.

  In step S502, a process for separating the image data represented by R′G′B ′ into ink colors (color separation process) is performed. The number of ink colors to be separated in this color separation process varies depending on the number of inks used in the recording apparatus. For example, if the recording apparatus uses four colors of ink, the image data is decomposed into four color image data of cyan (C), magenta (M), yellow (Y), and black (K). Furthermore, in the case of a recording apparatus that uses light cyan (LC) or light magenta (LM) ink in addition to these four color inks, the image data represented by R′G′B ′ is C, The image data is decomposed into a total of six colors, M, Y, K and LC, LM. In recent years, in addition to the above six inks, there are recording apparatuses that use inks of special colors such as gray ink, red, blue, and green. In this case, the image data is decomposed into 11 colors.

  In step S503, output gamma correction is performed to correct the lightness characteristics for each ink. This correction is performed using, for example, a one-dimensional lookup table. Furthermore, in S504, multi-valued image data for each ink color is subjected to halftone processing such as error diffusion processing and dither processing to generate recording data that defines the arrangement of dots to be recorded on the recording medium.

  In the image data processing steps described above, the ink hit amount of the input image data can be calculated using the image data for each ink color separated in S502. However, the calculation of the ink placement amount can be performed at any timing after S502, after S503, and after S504.

  Furthermore, depending on the input recording data, it is not always necessary to execute all the processes in the above-described processing steps S501 to S504. That is, if the input data has already been separated into ink colors, the image data omits S501 and S502, and the processing is executed from S503. If the input image data is already subjected to the output gamma correction process, the process may be executed from the halftone process in S504.

  In general, when an LUT used for the ink color separation process in S502 is provided by a printer manufacturer, at the stage where the process using the LUT is executed, the ink placement amount by the combination of inks of each color does not exceed a certain allowable amount. Various parameters are designed.

  However, in the case of image data provided by a third party, or the recording data of patches recorded when designing various image processing parameters, they are already separated into ink colors as input from the halftone processing stage of S504. Often it has been done. In addition, in color patch recording or the like required when designing an LUT that is used at each stage, such as S502 and S503, the ink usage amount correction processing by the LUT is not performed, and the ink ejection amount is allowed. In some cases, image data exceeding the limit is input. In such a case, in the present embodiment, the following correction is performed on the image data.

  FIG. 6 shows an example of the hit amount correction for the hit amount of ink calculated after color separation into image data of each ink color.

  FIG. 6A shows the amount of ink for each ink color of CMYK and the total before the amount of ink correction. In this example, three-color inks of CMY are used, but the total exceeds the allowable driving amount.

  On the other hand, FIG. 6B shows an example when the amount of ink for each ink color shown in FIG. 6A is corrected. In this example, the amount of ink that exceeds the allowable printing amount is equally divided by the number of inks used for recording (in this example, the number of inks is 3), and each ink that uses the equally divided amount is used. By subtracting from (CMY), the total of each ink falls within the allowable range.

  FIG. 7 is a flowchart showing an example of processing executed when a color patch is recorded in the present embodiment.

  In this embodiment, when recording a color patch for colorimetry, recording is performed by selecting a recording mode (patch recording mode) of a dedicated color patch. For this selection, the printer driver of the host PC may be provided with mode selection means for selecting a normal recording mode for recording a normal image and a color patch recording mode from a screen displayed on the display, or provided in the recording apparatus. It is good also as a structure selected on the provided panel.

  First, when color patch recording data is input, the main apparatus main control unit 408 in the recording apparatus first determines whether or not the shot amount correction setting is ON in S701. In the recording apparatus, the driving amount correction (driving limiter) process is ON by default, but this is a check when the recording apparatus has a function that can be turned OFF for a user who does not like the process.

  If the shot amount correction is OFF, the process proceeds to the recording operation as it is. If the shot amount correction is ON, whether or not the shot amount of the target pixel is equal to or greater than a preset threshold value in step S702. Make a decision. This threshold value is a value indicating the maximum ink placement allowable amount that can be applied to the recording medium as shown in FIG. 2B, and this threshold value may be determined for each type of recording paper or may be determined uniformly. It is also possible to end up. For example, the glossy paper may be 300%, the coated paper may be 260%, or may be uniformly 300%. In general, when ink is ejected by an ink jet recording apparatus, some electrical control such as heating and vibration is required, so that the amount of ink that can be ejected at one time is limited in terms of power supply capacity. For this reason, when the threshold value is uniformly determined, it is conceivable that the discharge limit amount is determined based on the ability. It is also possible to set the threshold value by user input.

  If it is determined in step S702 that the target pixel is equal to or greater than a preset threshold value for the amount of shot-in, it is further determined in step S703 whether or not the recording mode currently set is the patch recording mode. If it is determined that the mode is not the patch recording mode, the ink usage amount is corrected so that the driving amount is within the maximum allowable printing amount in S704. This correction includes, for example, a method called UCR in which color ink is replaced with black ink in addition to a method of reducing the amount of each ink used as shown in FIG. It is not limited to the method shown in FIG.

  If it is determined in S703 that the patch recording mode is selected, the ink usage amount in the recording data of the corresponding patch is set to zero. That is, recording data is created so that a patch without ink is formed. Thereafter, in step S706, a color patch is recorded based on the finally corrected recording data.

  In this color patch recording operation, only a color patch composed of pixels determined to be less than the threshold value in S702 is recorded on the recording medium with ink. On the other hand, the color patch composed of pixels determined to have an impact amount equal to or greater than the threshold value according to the determination in S702 does not apply ink to the recording medium, and the color of the patch is the ground color (for example, white) of the recording medium. . This prevents ink from overflowing on the recording medium in the created chart, and explicitly distinguishes which colorimetric value of the patch is reliable in correlation with the original image. can do.

An example of a color patch recorded through the above processing is shown in FIG.
FIG. 8A is an example of a color chart recorded without performing the correction process (the process shown in FIG. 9) in this embodiment. In this color chart, color patches are recorded with various combinations of ink colors, and the patches may include a patch P1 that exceeds the maximum allowable ink placement amount. In particular, in a multi-color printer that has recently been used such as 6 colors, 8 colors, and 11 colors, if the inks are stacked without any correction, the maximum allowable ink placement for one color is 100%. In some cases, a patch formed with a large driving amount such as 1100% may be included.

  On the other hand, FIG. 8B is an example showing a color chart obtained by performing the correction processing in the present embodiment on the recording data of the color patch shown in FIG. As shown in the figure, the color patch of the recording data determined to exceed the maximum ink ejection amount is explicitly shown as the ground color of the recording medium (here, white). Therefore, it is possible to reliably determine a chart that exceeds the maximum allowable ink ejection amount from the recorded charts by the reading device and visual observation. It should be noted that, based on the recorded chart, the input for designating the chart that is the ground color (white) of the recording medium is automatically performed based on the form that the user views the chart or the result of reading the color chart by the reading device 302. It is possible to take any of the forms to input automatically.

  FIG. 9 is a flowchart showing an example of processing for automatically determining which part exceeds the amount of shots, based on the values measured by the colorimetric device 302.

  First, in step S901, the number of a patch to be processed is initialized. In step S902, the colorimetric value of the ground color (here, white) of the recording medium existing in the chart is read, and in step S903, the colorimetric value of the patch having the number to be processed is read.

  In step S904, it is determined whether the patch to be processed is a patch having a color close to white, which is the ground color of the recording medium. In this embodiment, the presence of a patch recorded by applying ink to the recording medium is determined using the color difference between the color of the patch and white, which is the ground color of the recording medium. For this reason, in order to avoid a bright-colored patch portion from being determined as a portion to which no ink is applied due to a small color difference from the recording medium in the following determination, even if there is no problem in the amount of shot. Then, the process of S904 is performed.

  In step S905, the color difference between the colorimetric value of the patch and white, which is the ground color of the recording medium, is calculated. In step S906, it is determined whether the calculated color difference is within a preset threshold. It should be noted that a certain amount of background color difference exists partially even in a white background recording medium, and there are also measurement errors and the like, and therefore the threshold value is set in view of these.

  For example, in white glossy paper, if the color difference ΔE is within 1.5, it is determined as white. In this embodiment, the color difference using the Lab value defined by the CIE is used as the value representing the color difference. However, the color difference may be determined only by the lightness in the Lab. Alternatively, the determination may be made using the difference in density value.

Hereinafter, the determination based on the color difference will be described as an example.
Here, the most basic formula for defining the color difference ΔE in the recording medium is shown below.
Now, if the colorimetric values on the front side of the recording medium are (L1, a1, b1) and the colorimetric values on the back side are (L2, a2, b2),
ΔE = ((L1-L2) ² + (a1-a2) ² + (b1-b2) ² ) ^1/2
As required.
Although this calculation formula has also been improved several times (such as ΔE2000), these new calculation formulas may be used for the determination.

  If the color difference ΔE calculated using the above formula is within the above threshold value in S906, it is determined that the patch portion of the recording medium is the same as the white color of the recording medium to be used, and the patch is not used. It is set as a patch (S907). Thereafter, in S908, the patch number is incremented by 1 (+1), and in S909, it is determined whether or not all patches have been processed. If the processing has been completed for all patches, the processing is terminated. If all processing has not been completed, the processing returns to S903, and the processing up to S909 is executed for the next numbered patch.

  By executing the flow as described above, it is determined which patch in the recorded chart is a patch that gives a colorimetric value that can be used when designing an image processing parameter such as a color conversion parameter. Is possible. Then, the image processing parameter is calculated using only the determined reliable colorimetric value of the patch.

  FIG. 10 is an explanatory diagram showing an example of a method for setting image processing parameters using only the reliable colorimetric values of the patch specified as described above. In the figure, as a part of the color patch for performing color measurement, a color measurement value of a blue patch composed of cyan and magenta is extracted.

  FIG. 10A shows the tone values of the image data corresponding to the ink placement amounts of cyan (C) and magenta (M) for recording the blue patch in the chart recorded in this embodiment. A value (colorimetric value) obtained by measuring the color of each recorded patch with a colorimetric device is shown. In FIG. 10A, since the gradation value of each color is represented by 8 bits, 0 is the minimum value of the gradation value, and 255 is the maximum value. For this reason, a patch having a cyan gradation value of 255 and a magenta gradation value of 255 originally has an ink ejection amount of 200%.

  Here, for example, assuming that the maximum ink placement allowable amount on the recording medium is 150%, in the patch shown in FIG. 10A, a highly reliable patch whose ink placement amount is within the maximum ink placement allowable amount is C and Each patch has a gradation value of M of 187 or less. A patch whose cyan and magenta gradation values exceed 187 (a patch surrounded by a thick frame in FIG. 10A) has an ink ejection amount that exceeds a threshold value, and is recorded according to image data. However, the reliability as a patch is low. Therefore, for the patches in which the gradation values of C and M exceed 187, ink is not applied in the present embodiment, so the colorimetric values of these patches are white values that are the background colors of the recording medium. .

  If you need more patch data than the number of reliable patches recorded as described above for operations such as profile creation, interpolation is performed based on the colorimetric values of reliable patches. To reconstruct the colorimetric values of the patch and perform the calculation.

  Of course, depending on the algorithm of the profile creation algorithm, it is possible to perform the calculation without performing such interpolation. In that case, the calculation can be performed using only the colorimetric values of the highly reliable patch. Good.

  According to the above-described embodiment, even when the input patch image data exceeds the maximum ink ejection allowable amount, it is possible to use only the reliable colorimetric values of the patch. For this reason, when recording a patch, it is not necessary to change the image data of the patch every time the recording medium is changed or to create a patch print file for each type of recording medium. Accordingly, image processing parameters such as an ICC profile can be quickly and appropriately performed, and it is not necessary to expand the memory capacity for storing the print file, thereby preventing an increase in cost.

(Other embodiments)
In the above-described embodiment, the patch is formed with the background color of the recording medium without applying ink to the recording medium for the patch exceeding the maximum ink placement allowable amount of the recording medium to be used. However, the present invention is not limited to this, and patches that exceed the maximum ink placement allowance may be recorded by being replaced with predetermined specific characters, symbols or figures, for example, X marks. Good. In this case as well, it is possible to explicitly visually confirm which patch has exceeded the shot amount. Furthermore, even when using a color measuring device for color measurement, the position of the patch can be specified by extracting a pattern such as a specific character, symbol or figure from the read image. Similarly, it is possible to perform image processing using only reliable patches.

  The object of the present invention can also be achieved by using a storage medium storing software program codes for realizing the functions described above in the following form.

  That is, the storage medium may be supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

  In this case, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, a DVD, or the like is used as a storage medium for supplying the program code. be able to.

  Further, the present invention is not limited to the case where the functions of the above-described embodiments are realized by executing the program code read by the computer. That is, according to the present invention, an operating system (OS) running on a computer performs part or all of actual processing based on an instruction of a program code, and the functions of the above-described embodiments are realized by the processing. This includes cases where

  Furthermore, the present invention performs the following processing after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. It is also possible to adopt a form such as That is, according to the present invention, the CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing based on the instruction of the program code, and the function similar to the above-described embodiment is realized by the processing. The form to be included is also included.

Claims (11)

An acquisition means for acquiring input image data of each of a plurality of patches to be recorded on a recording medium by an inkjet recording apparatus;
Calculating means for calculating the amount of ink applied to the recording medium of each of the plurality of patches based on input image data of each of the plurality of patches;
Image data for recording a patch in which the ink ejection amount calculated by the calculation unit exceeds the maximum ink ejection allowable amount determined on the recording medium is converted into image data different from the input image data of the patch. Conversion means to
An image processing apparatus comprising:   The conversion means replaces input image data of a patch whose ink ejection amount calculated by the calculation means exceeds the maximum ink ejection allowable amount with image data that does not apply ink to the recording medium. Item 8. The image processing apparatus according to Item 1.   The conversion unit records the input image data of a patch whose ink ejection amount calculated by the calculation unit exceeds the maximum ink ejection allowable amount, and a patch having a form different from the patch within the maximum ink ejection allowable amount. The image processing apparatus according to claim 1, wherein the image processing apparatus is replaced with image data for use.   The image processing apparatus according to claim 3, wherein the patch having a shape different from the patch within the maximum ink placement allowable amount is formed of a character or a figure. Colorimetric means for performing colorimetry for each of the plurality of patches recorded on the recording medium by the ink jet recording apparatus based on the image data converted by the conversion means and the input image data of each of the plurality of patches; ,
Of the colorimetric values of each of the plurality of patches obtained by the colorimetric means, the colorimetric value of the patch whose ink placement amount exceeds the maximum ink placement allowance is not used, and the ink placement amount is the maximum ink placement allowance. Generating means for generating image processing parameters using only the colorimetric values of patches within the capacity;
The image processing apparatus according to claim 1, further comprising:   The generating means includes a colorimetric value of a patch in which an ink placement amount exceeds the maximum allowable ink placement amount and a maximum ink placement amount among the colorimetric values of each of the plurality of patches obtained by the colorimetry means. A profile is generated by using only the colorimetric values obtained by excluding the colorimetric values of the patches close to the ground color of the recording medium from the colorimetric values of the patches that are within the allowable ink placement amount. The image processing apparatus according to claim 1.   The image processing apparatus according to claim 5, wherein the color conversion parameter generated by the generation unit is a profile or an output gamma. An acquisition step for acquiring input image data of each of a plurality of patches to be recorded on a recording medium by an inkjet recording apparatus;
A calculation step of calculating an amount of ink applied to the recording medium of each of the plurality of patches based on input image data of each of the plurality of patches;
Converting image data for recording a patch in which the ink ejection amount calculated in the calculation step exceeds the maximum ink ejection allowable amount determined on the recording medium into image data different from the input image data of the patch Conversion process to
An image processing method comprising: An inkjet recording apparatus capable of recording a plurality of patches constituting a chart for generating parameters in image processing based on recording data of the patches,
An acquisition means for acquiring input image data of each of a plurality of patches to be recorded on the recording medium;
Calculating means for calculating the amount of ink applied to the recording medium of each of the plurality of patches based on input image data of each of the plurality of patches;
Image data for recording a patch in which the ink ejection amount calculated by the calculation unit exceeds the maximum ink ejection allowable amount determined on the recording medium is converted into image data different from the input image data of the patch. Conversion means to
An ink jet recording apparatus comprising:   The inkjet according to claim 9, further comprising: a mode selection unit that selects a patch recording mode for recording the patch and a normal recording mode for recording an input image different from the patch. Recording device.   Means for changing processing when the amount of ink applied to the recording medium exceeds a threshold value when the normal recording mode is selected and when the patch recording mode is set. The ink jet recording apparatus according to claim 10.