JP2009272832A - Image processing apparatus, method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that color matching between media having different white dots has decreased in precision of a gray line. <P>SOLUTION: When black-and-white correction parameters of a device dependent color space and a device independent color space of an output device are generated, after conversion to the device dependent color space and device independent color space is performed, black-and-white corrections based upon black-and-white correction parameters of an input device are made on a color reproduction range further after the conversion, and conversion for mapping white dots after the black-and-white corrections to white in the device independent color space is carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, method, and program, and more particularly, to an image processing apparatus, method, and program for performing black and white correction based on a media white point when performing color matching processing between devices.

  In general color matching between devices, input data in the RGB or CMYK color space, which is a device value, is input to an XYZ or L * a * b * color space, which is a device-independent color space, depending on the source profile (correction parameter). Converted. Since colors outside the color reproduction range of the output device are not represented by the output device, all colors are converted to a device-independent color space (device-independent color space) so that they fall within the color reproduction range of the output device. Color space compression is applied to the input data. After color space compression is performed, the input data is converted from the device-independent color space to CMYK data, which is the device-dependent color space of the output device. The color space compression and conversion to the color space of the output device are converted by the destination profile.

  In color matching using this color profile, the sample is represented by an ideal medium (medium), that is, a medium in which the white point corresponds to complete reflection and the black point corresponds to complete absorption. However, the medium actually used is not ideal. For example, since CRT has a light source color, black is not completely absorbed, and printed matter has an object color, and white is not completely reflected. For this reason, the gray line in the color reproduction range of the device differs depending on the medium, and when only one medium is observed, white is perceived as white and black is black, but when images on different media are observed, white and black are Perceived as different.

Therefore, a color profile in which white in the device's color reproduction range is measured in a device-independent color space and converted to a color perception space, and white on the medium is corrected in the color perception space to match the gray lines. A technique using the above has been proposed (see Patent Document 1).
JP 2002-94811 A

  However, when using relative color matching based on a profile corrected by such a conventional black and white correction method, if the white points of the input and output media are too far apart, the matching accuracy is lowered. In particular, there is a problem that the accuracy is lowered particularly in a gray line in a combination in which the white point of the input medium and the output medium is positioned so as to sandwich the L * axis in the L * a * b * color space.

  For example, the image data is converted from the color space of the input device to the L * a * b * color space using the profile of FIG. The profile converts the color reproduction range of the input device to the color reproduction range 2001 of the L * a * b * color space, and further, the white point 2002 indicates the white color of the L * a * b * color space. It is like converting to a mapped color reproduction range 2003. A point indicating white in the L * a * b * color space is represented by (100, 0, 0). Further, the converted image data is inversely converted from the L * a * b * color space to the color space of the output device using the profile of FIG. The profile converts the color reproduction range of the output device to the color reproduction range 301 of the L * a * b * color space, and further, the white point 3002 indicates the white of the L * a * b * color space. It is like converting to a mapped color reproduction range 3003.

  Color matching processing in such an input / output combination is performed as shown in FIG. In this way, the image data input from the input device has its color reproduction range 2001 converted into a color reproduction range 2003 corrected in black and white (this is called normalization), and further converted into a color reproduction range 3001 of the output device. Output after being done.

  For example, the white point CMYK = 0, 0, 0, 0 on the input side is converted to L * a * b * = 90.1, −0.11, 1.69 by a given conversion formula (known). Is done. This value indicates white in the color reproduction range, and is converted into L * a * b * = 100, 0, 0 indicating white in the L * a * b * color space by the source profile. L * a * b * = 100, 0, 0 is converted to CMYK = 0, 0, 0, 0 by the destination profile. When CMYK = 0, 0, 0, 0 in the output device is actually output and colorimetrically measured, L * a * b * = 95, 4, -2, 13, -4, 50. As described above, the position of the white point in the L * a * b * space may differ depending on the ground color of the medium on which the image is recorded or the ground color of the medium on which the image is recorded. Under conditions where the white point of the input device greatly moves from the white point of the output device, the gray line also moves greatly, and the color reproduction accuracy decreases.

  The present invention has been made in view of the above-described conventional example. Image processing capable of generating a correction parameter capable of performing black-and-white correction to reduce a gray line shift even in color matching in which a white point greatly moves depending on input / output conditions. An object is to provide an apparatus, a method, and a program.

In order to achieve the above object, the present invention comprises the following arrangement. That is, an image processing apparatus that performs color matching processing between devices having different color reproduction ranges,
A color corresponding to white in the first color reproduction range with respect to the first color reproduction range expressing the color reproduction range of the first device based on the color sample recorded on the medium in a device-independent color space. Obtaining means for obtaining a first correction parameter for performing black and white correction so as to associate a value with a white color value in the device-independent color space;
A color reproduction range obtained by converting the color reproduction range of the second device based on the color sample recorded on the medium into the second color reproduction range expressed in a device-independent color space using the first correction parameter. Generating means for generating a second correction parameter for black and white correction so that the color value corresponding to the white color in the device corresponds to the white color value in the device-independent color space.

According to still another aspect, the present invention comprises the following configuration. An image processing apparatus that performs color matching processing between devices having different color reproduction ranges,
The image data input from the first device and expressed in the device-dependent color space of the first device is converted into a device-independent color space representation, and the image data based on the color sample recorded on the medium is further converted. Monochrome correction is performed so that a color value corresponding to white in the first color reproduction range in which the color reproduction range of one device is expressed in the device-independent color space is associated with a white color value in the device-independent color space. First conversion means for black and white correction using the first parameter for
A color reproduction range obtained by converting the color reproduction range of the second device based on the color sample recorded on the medium into the second color reproduction range expressed in a device-independent color space using the first correction parameter. Using the second correction parameter for black and white correction so that the color value corresponding to white in the device corresponds to the white color value in the device-independent color space, the device-independent color space And a second conversion unit that reversely corrects the image data converted to, and further converts the representation of the device-independent color space into a representation of the device-dependent color space of the second device.

  According to the present invention, there is an effect that perceptual color reproduction accuracy is hardly lowered even in color matching in which a white point moves greatly depending on input / output conditions.

[First Embodiment]
FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus that performs color matching processing according to the present exemplary embodiment. The color matching process is a process for matching colors between a plurality of devices having different color reproduction ranges. Here, the color reproduction range of the image input device is referred to as a first color reproduction range, and the color reproduction range of the image output device is referred to as a second color reproduction range. However, when color matching is performed between two image input devices or between two image output devices, the first and second color reproduction ranges are the same type of device color reproduction range.

  Image data 1001 read by the image input device is converted into a device-independent color space. This corresponds to the first conversion. The converted image data is subjected to black and white correction by the source profile, that is, the first correction parameter 1002, and becomes image data in the PCS (profile connection space) 1003. The image input device is also simply referred to as an input device and corresponds to the first device. The image data is inversely corrected with the destination profile, that is, the second correction parameter, and further inversely converted into image data 1005 in the device-dependent color space of the image output device. This corresponds to the second conversion. An image output device is also simply called an output device. Here, the conversion from the device-dependent color space to the device-independent color space is referred to as “conversion” and vice versa as “inverse conversion”. In addition, the black and white correction in the L * a * b color space is called “black and white correction”, and the process of converting the black and white corrected image data to uncorrected data is called “reverse correction”. In the present embodiment, an apparatus and a method for appropriately determining the second correction parameter used for reverse correction will be described.

  FIG. 5 is an example of a system configuration used in the present embodiment. The processing shown in FIG. 1 and the like is realized by the computer system of FIG. In FIG. 5, the CPU 101 controls the entire system and executes processing such as generating a profile by executing a program or converting image data by applying the profile. A ROM 102 is a read-only memory, and is connected to the CPU 101 via a bus 104 together with a random access memory (RAM) 103. The CPU 101 can directly execute a program stored in the ROM 102 or the RAM 103. An input interface 105, HDD interface 107, video interface 109, and output interface 111 are also connected to the bus 104. An input device 106 such as a keyboard, mouse, or colorimeter can read information from the CPU 101 via the input interface 105. The secondary storage device HDD 108 such as a hard disk device or an optical disk device can be read and written via the HDD interface 107. Data stored on the HDD 108 can be expanded on the RAM 103 by using an appropriate means. Similarly, the data developed on the RAM 103 can be stored in the HDD 108 by using an appropriate means. The CPU 101 can also execute the data stored in the HDD 108 expanded on the RAM 103 as described above as a program. Arbitrary characters or images can be displayed on the monitor 110 by causing the CPU 101 to operate the video interface 109. An output device 112 such as a printer or a plotter can send information via the output interface 111. Similarly to the case of the input device 106, the CPU 101 can also read device information unique to the printer such as the model name and color gamut information of the output device 112 via the output interface 111.

<Generation of conversion characteristics and conversion grid>
FIG. 6 is a diagram showing a general outline for generating a conversion characteristic grid from device-dependent color signals to device-independent color signals. Although the configuration of FIG. 6 may be realized by hardware, in the present embodiment, it is realized by software. The control unit 208 controls the conversion unit 201, for example, reads an output color patch and converts the color value of the color patch into a device-independent color space value that has been subjected to black and white correction. This is the conversion characteristic. Based on this conversion characteristic, the conversion grid generation unit 209 generates a conversion grid (lookup table) in which a specific sample color is associated with the converted color. The conversion grid that associates the values before and after conversion is used to convert the color value of the sample point in the input color space into the color value in the output color space. Since the obtained conversion grid is a discrete table having, for example, sample colors as grid points, at the time of conversion, colors that are not registered in the basic conversion characteristics table are linearly interpolated, for example, at the four most recent sample points. And convert it.

  The conversion characteristic obtained by the conversion unit 201 maps the basic conversion characteristic indicating the correspondence between the device-dependent color space and the device-independent color space, and white converted by the basic conversion characteristic to white in the color space. Black and white correction parameters. The black and white correction parameter may be simply referred to as a correction parameter. However, since black and white correction cannot be performed when generating the black and white correction parameters of the output device, first, conversion characteristics indicating basic conversion characteristics are obtained, and black and white correction parameters are generated based on the conversion characteristics.

  In order to generate change characteristics, the conversion unit 201 first reads the patch chart 202 from the storage unit 207, outputs the patch chart 202 via an output device that is a conversion characteristic generation target, and performs colorimetry with a colorimeter to obtain device-independent colors. A signal (absolute value) 204 is acquired. In FIG. 6, the output / colorimetry unit 203 performs the output, but the output is performed by the output device, and the colorimetry is performed by the colorimeter. Examples of patch charts include CMYK928 colors such as IT8.7 / 3. The colorimeter includes a three-channel colorimetric sensor type and a spectrophotometer sensor type. The spectrophotometer sensor type is characterized by higher accuracy but higher cost. The correspondence between the color value in the device-dependent color space of the output device (second device) showing the color sample of the patch chart and the color value in the device-independent color space obtained by colorimetry is the basic conversion characteristics of the output device. It becomes.

  The device-independent color signal (absolute value) acquired by color measurement is converted into a device-independent color signal (relative value) 206 by the black and white correction unit 205. In the ICC, as an example of the relative value when PCS is set to L * a * b *, there is conversion in which the white point of the media is L * a * b * = 100, 0, 0. Also in this embodiment, the white point of the medium is corrected as L * a * b * = 100, 0, 0. In particular, for the output device, the conversion characteristic generation unit 208 performs black and white correction by setting the white point of the media to L * a * b * = 100, 0, 0 based on the black and white correction parameter of the input device (the reverse of this when outputting). Correction parameters) are generated. This applies the conversion characteristics of the input device to the color reproduction range of the output device expressed in device-independent color space by measuring the color sample of the patch chart, and corresponds to white in the obtained color reproduction range This is a black and white correction parameter (second correction parameter) that associates a grid point with a white color value in a device-independent color space. Note that this is a correction performed at the time of actual color matching, and the black and white correction parameter is not obtained when generating the basic conversion characteristics of the output device. Therefore, the black and white correction need not be performed at this stage. Further, as described later, since the monochrome correction of the output device is performed based on the monochrome correction parameter of the input device, the monochrome correction may be performed using the monochrome correction parameter of the input device at this stage.

  On the other hand, an input device can be corrected to white using a monochrome correction parameter (source profile) uniquely given to the input device. A characteristic for mapping the color value of the white point described in the profile to the white point of the device-independent color space is the monochrome correction parameter (that is, the first correction parameter) of the input device. For input devices, it is desirable that not only the white point be mapped. For example, in the LUT having the basic conversion characteristics, the luminance of the black point in the color reproduction range is Lbk, and the luminance of the white point is Lw. Then, the value L of the luminance component of the target lattice point (that is, the luminance component after conversion using the LUT) is converted to Lbk + (L−Lbk) * (100−Lbk) / (Lw−Lbk). This is done by paying attention to all grid points. Thus, the luminance component is linearly converted with the white point having the luminance of 100 with the black point in the color reproduction range as a reference. On the other hand, for the color difference component, correction for shifting the white point in the color reproduction range onto the achromatic color axis is performed for all grid points. That is, the conversion is performed by translating all grid points in the color difference direction. These conversions are black and white correction parameters that associate the white point of the basic conversion characteristics of the input device with the white color value in the device-independent color space. Of course, by performing this conversion on the basic conversion characteristics, it is also possible to obtain an LUT in which the monochrome conversion parameter is superimposed on the basic conversion characteristics. Of course, this monochrome correction parameter is only an example.

  If the monochrome correction parameter of the input device is included in the device-specific source profile, it is sufficient to use it, and it is not necessary to generate it again. However, when it is newly generated, it is generated as described above. To explain this simply, first read the color sample of the patch chart with the input device, then measure the color of the patch chart, and the basic conversion characteristics between the device-dependent color space and the device-independent color space in the color reproduction range Get. A black and white correction for correcting black and white so that the color value corresponding to white in the color reproduction range of the input device expressed in the device independent color space based on the color sample corresponds to the white color value in the device independent color space A parameter (first correction parameter) is obtained. The monochrome correction parameters of the input device are obtained as described above.

  For example, as in Patent Document 1, not only a white spot but also a black spot may be converted. Also, as disclosed in Patent Document 1, it may be converted into a cone response signal and a black and white correction parameter for performing black and white correction in a color adaptation model or a color perception space may be generated. When performing black and white correction in the color perception space, the black and white correction parameters in the color perception space may not be included in the source profile. In that case, the matrix M described in Patent Document 1 is applied to convert it into a cone response signal (that is, a color perception space), and the monochrome correction parameter in the color perception space is the L * a * b * color described above. It can be obtained in the same way as space.

  When the conversion characteristic is generated by the conversion characteristic generation unit 209, the device-dependent color signal grid 210 (for example, RGB 9 × 9 × 9 points or CMYK 9 × 9 × 9 × 9 points) is read from the storage unit 207. A conversion grid of device-dependent color signal-device-independent color signal is obtained by converting a value obtained by converting each point of the grid into a device-independent color signal by the conversion unit 201 into a lookup table in association with the grid point. . The grid points may be part of the patch chart, for example.

  As described above, the change grid generation unit 209 generates device-dependent color signal-device-independent color signal conversion characteristics (basic conversion characteristics for output devices) and stores them in the storage unit 207.

<Black and white correction parameters>
Next, details of the black and white correction unit 205 that reduces the gray line shift in color matching in the case where the white point of the input / output medium is greatly separated in the present embodiment will be described with reference to FIG. FIG. 7 illustrates black and white correction in the color perception space. For example, the white point of the input / output media is far apart from the color converted by applying the basic conversion characteristics to the white of the input device and the color converted by applying the basic conversion characteristics to the white of the output device. Is a position sandwiching the achromatic color axis. This can be determined, for example, in the L * a * b * color space. In this embodiment, it is not determined that the white point of the input / output medium is far away, and the black and white correction parameter when the white point of the input / output medium is far away is used in all cases. However, the white color value in the color reproduction range of the input device before black-and-white correction processing is compared with the white color value in the color reproduction range of the output device before black-and-white correction processing in the device-independent color space. The determination can be made based on the positional relationship in the space. In this case, if it is determined that the white point of the input / output medium is greatly separated, the monochrome correction parameter of the output device in this embodiment is used. Otherwise, the monochrome correction parameter for the output device is created and used in the same manner as described for the monochrome correction parameter for the input device. Hereinafter, the monochrome correction parameters in the color perception space will be described.

  In FIG. 7, the input device-independent color signal is converted into a cone response signal by the device-independent color signal-cone response conversion processing unit 303 and sent to the monochrome processing unit 304. The conversion from the device-independent color signal to the cone response signal is performed by, for example, linear conversion using a 3 × 3 matrix M using a Von Kries chromatic adaptation model. Although several matrix M can be considered, for example, the chromaticity coordinates of the primary color of the basic spectral sensitivity obtained by Pitt and Esteves may be used. In addition, the black and white correction parameter generation unit 305 generates a black and white correction parameter. As parameters, there are parameters for determining four correction directions of the pre-correction white point OW, the pre-correction black point OB, the post-correction white point NW, and the post-correction black point NB in the cone response signal. The black and white correction processing unit 304 performs black and white correction on the input cone response signal according to the black and white correction parameter and outputs the result. The cone response-device-independent color conversion unit 306 converts the monochrome response-corrected cone response signal into an independent color signal and stores it in the storage unit 302.

  Subsequently, a method for creating the output side monochrome correction parameter in consideration of the input side conversion characteristic, particularly the monochrome correction parameter, will be described by taking the output side conversion characteristic in color matching as an example. In the input device profile (source profile), for example, as shown in FIG. 8, there are copyright information, white point, black point, conversion characteristic grid data, description, and the like. This profile is read from the storage unit 207, and among these, monochrome correction parameters are generated in consideration of the media white point information. This method will be described with reference to the flowchart of FIG. The procedure in FIG. 9 is generated by the black and white correction parameter generation unit 305. In the present embodiment, the black and white correction parameter generation unit 305 is realized by the CPU 101.

  First, the source profile of the input device is read (402). Subsequently, the white point information of the input medium is acquired from the read source profile (403). Based on the white point information, a monochrome correction parameter of the output device is calculated (404). Then, using the black and white correction parameter, the colorimetric value on the output side is black and white corrected (405). FIG. 10 shows the state of black and white correction in the above case. The monochrome correction direction of the input device and the monochrome correction direction of the output device are the same. By performing such correction, there is no shift in input / output color components, so that stable accuracy can be obtained in ICC color matching. In other words, even if the pre-correction white point OW having various colors is input, the color measurement value on the output side is corrected in accordance with the input, so that the deviation regarding the color of the gray line is substantially eliminated.

  However, with this method, the pre-correction white point OW is reproduced on the output medium. That is, the ground color of the input side paper is placed on the output side paper. In order to avoid this, as shown in FIG. 11, the white point information of the input side medium is taken into consideration, and then the white point of the medium is corrected to L * a * b * = 100, 0, 0. do it. However, in this case, since the gradation of highlight may be deteriorated, not only the white point of the media as shown in FIG. 11 but also the neighboring colors as shown in FIG. It is effective to apply processing. There are several possible smoothing methods. For example, the color signal grid is approximated by a Bezier surface or a B-spline surface and deformed by morphing, or the color signal grid is expressed by a three-dimensional finite element method. Deformation may be used.

  In step 404 of FIG. 9, monochrome correction parameters as shown in FIG. 11 or 12 are generated.

  As described above, the white point information of the input side medium is taken into consideration at the time of black and white correction, and the colorimetric value on the output side is corrected in black and white in the same correction direction as the input side. By doing so, it is possible to eliminate a shift relating to the color of the gray line in the color matching when the white point of the input / output medium is greatly separated.

  Although correction is performed in the color perception space in FIG. 9, this may be in a device-independent color space. For example, correction may be performed in a luminance color difference color space (L * a * b *).

[Second Embodiment]
When considering the conversion characteristics on the input side in FIG. 9 and considering only the white point information of the input medium, the black and white correction on the input side cannot always be accurately estimated. In such a case, by considering the device-dependent color signal-device-independent color signal conversion grid on the input side, the output side can be corrected in black and white with a method close to the input side black and white correction with higher accuracy. In FIG. 13, a flowchart of black and white correction in which conversion characteristic grid information is also considered as the conversion characteristic on the input side will be described.

  First, the conversion characteristic data 502 on the input side is read (501). The white point information of the input medium and device-dependent color signal-device-independent color signal conversion characteristic grid point information are acquired from the read conversion characteristic data (503). A principal component analysis is performed on the acquired conversion characteristic grid information to obtain a principal component vector (504). The principal component vector is obtained up to the first principal component, the second principal component, the third principal component, and three principal components. An intersection P between the principal component vector having the highest correlation with the L * axis direction and the L * = 100 plane among the obtained principal component vectors is obtained (505). On the other hand, the coordinate mW at L * a * b * is obtained from the acquired white point information of the input medium, and the monochrome correction parameter is calculated using the straight line direction connecting mW and P as the monochrome correction direction of the colorimetric value on the output side. (506). The colorimetric value on the output side is corrected in black and white based on the black and white correction parameter (507).

  The outline of the above black and white correction will be described with reference to FIG. The point cloud is obtained from the input side conversion grid characteristics. The principal component vector l is a vector having the highest correlation with the L * -axis direction obtained at 504. The straight line m is a straight line parallel to the principal component vector l, and the point at which the straight line connecting the straight line m and the white point mW of the medium intersects the plane L * = 100 serves as a parameter for black and white correction, and the correction vector n is obtained. There are several possible correction vectors h other than the method of obtaining the principal component vector l. For example, a straight line connecting a white point and a black point may be treated as a correction vector.

  As described above, by considering the conversion characteristics on the input side at the time of black and white correction, it is possible to perform black and white correction on the output side in a method similar to the black and white correction on the input side. As a result, it is possible to eliminate a shift related to the color of the gray line in color matching when the white point of the input / output medium is greatly separated.

<Other embodiments>
Note that the present invention can be applied to a system (for example, a copier, a facsimile machine, etc.) consisting of a single device even if it is applied to a system composed of a plurality of devices (eg, a host computer, interface device, reader, printer, etc.). You may apply. Another object of the present invention is to supply a recording medium recording a program for realizing the functions of the above-described embodiments to a system or apparatus, and for the computer of the system or apparatus to read and execute the program stored in the storage medium. Is also achieved. In this case, the program itself read from the storage medium realizes the functions of the above-described embodiment, and the program itself and the storage medium storing the program constitute the present invention.

  In the present invention, the operating system (OS) running on the computer performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing. This is also included. Furthermore, the present invention is also applied to a case where a program read from a storage medium is written in a memory provided in a function expansion card inserted into a computer or a function expansion unit connected to the computer. In that case, based on the instruction of the written program, a CPU or the like provided in the function expansion card or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

A conceptual diagram showing color matching between different general devices, A diagram showing a typical black-and-white correction, A diagram showing a typical black-and-white correction, A diagram showing how color matching works when the white points of the input and output media are separated. Hardware configuration diagram for realizing the image processing apparatus; The figure which showed the processing flow which implement | achieves the black-and-white correction process of this invention, The figure which showed the detail of the monochrome correction processing flow of this invention, Figure showing the information stored in the conversion characteristic data of general device-dependent color signal-device-independent color signal, Flow chart for black and white correction of output side colorimetric values considering white point information of input media, The figure which showed the monochrome correction direction of the output side colorimetric value considering the white point information of the input media, The figure which showed the outline | summary of the process which does not put ground color on the paper white of the black-and-white correction of this invention, The figure which showed the outline | summary at the time of considering gradation property in the process which does not put ground color on the paper white of the said black-and-white correction Flow chart for black-and-white correction of output-side colorimetric values taking into account device-dependent color signal-device-independent color signal conversion grid information, It is the figure which showed the outline | summary of the black-and-white correction | amendment of the output side colorimetric value which considered the device side color signal-device independent color signal conversion grid | lattice information of the input side.

Claims (9)

An image processing apparatus that performs color matching processing between devices having different color reproduction ranges,
A color corresponding to white in the first color reproduction range with respect to the first color reproduction range expressing the color reproduction range of the first device based on the color sample recorded on the medium in a device-independent color space. Obtaining means for obtaining a first correction parameter for performing black and white correction so as to associate a value with a white color value in the device-independent color space;
A color reproduction range obtained by converting the color reproduction range of the second device based on the color sample recorded on the medium into the second color reproduction range expressed in a device-independent color space using the first correction parameter. An image processing apparatus comprising: generating means for generating a second correction parameter for performing black and white correction so as to associate a color value corresponding to white in the color with a white color value in the device-independent color space . First conversion means for converting image data input from the first device into a representation of the device-independent color space, and performing black and white correction using the first correction parameter;
The image data converted into the device-independent color space by the first conversion unit is inversely corrected using the second correction parameter, and the device-dependence of the second device is expressed from the representation of the device-independent color space. The image processing apparatus according to claim 1, further comprising a second conversion unit that converts the color space into an expression.   The image processing apparatus according to claim 1, wherein the first device is an image input device, and the second device is an output device.   The image processing apparatus according to claim 1, wherein the device-independent color space is any one of a luminance-color difference color space and a color perception space. An image processing apparatus that performs color matching processing between devices having different color reproduction ranges,
The image data input from the first device and expressed in the device-dependent color space of the first device is converted into a device-independent color space representation, and the image data based on the color sample recorded on the medium is further converted. Black and white correction is performed so that a color value corresponding to white in the first color reproduction range in which the color reproduction range of one device is expressed in the device-independent color space is associated with a white color value in the device-independent color space. First conversion means for black and white correction using a first correction parameter for
A color reproduction range obtained by converting the color reproduction range of the second device based on the color sample recorded on the medium into the second color reproduction range expressed in a device-independent color space using the first correction parameter. Using the second correction parameter for black and white correction so that the color value corresponding to white in the device corresponds to the white color value in the device-independent color space, the device-independent color space And a second conversion unit that reversely corrects the image data converted into the image data and further converts the device-independent color space representation into the device-dependent color space representation of the second device. Image processing device. An image processing method in an image processing apparatus that includes an acquisition unit and a generation unit and performs color matching processing between devices having different color reproduction ranges,
In the first color reproduction range, the acquisition unit has a first color reproduction range expressing the color reproduction range of the first device based on the color sample recorded on the medium in a device-independent color space. An acquisition step of acquiring a first correction parameter for performing black and white correction so that a color value corresponding to white corresponds to a white color value in the device-independent color space;
The generating means uses the first correction parameter for the second color reproduction range in which the color reproduction range of the second device based on the color sample recorded on the medium is expressed in a device-independent color space. A generation step of generating a second correction parameter for performing black and white correction so that the color value corresponding to white in the converted color reproduction range corresponds to the white color value in the device-independent color space. An image processing method. An image processing method in an image processing apparatus that includes a first conversion unit and a second conversion unit, and performs color matching processing between devices having different color reproduction ranges,
The first conversion means converts the image data input from the first device and expressed in the device-dependent color space of the first device into a device-independent color space representation, and further recorded on the medium The color value corresponding to the white color in the first color reproduction range in which the color reproduction range of the first device based on the obtained color sample is expressed in the device-independent color space is determined as the white color in the device-independent color space. A first conversion step for black and white correction using a first correction parameter for black and white correction to correspond to a value;
The second conversion means sets the first correction parameter to the second color reproduction range in which the color reproduction range of the second device based on the color sample recorded on the medium is expressed in a device-independent color space. The first conversion is performed using a second correction parameter for performing black and white correction so that the color value corresponding to white in the color reproduction range converted by using the color value corresponds to the white color value in the device-independent color space. A second conversion step that reversely corrects the image data converted into the device-independent color space by the step, and further converts the representation of the device-independent color space into a representation of the device-dependent color space of the second device; An image processing method comprising: A program for performing color matching processing between devices having different color reproduction ranges by a computer,
A color corresponding to white in the first color reproduction range with respect to the first color reproduction range expressing the color reproduction range of the first device based on the color sample recorded on the medium in a device-independent color space. Obtaining means for obtaining a first correction parameter for performing black and white correction so as to associate a value with a white color value in the device-independent color space;
A color reproduction range obtained by converting the color reproduction range of the second device based on the color sample recorded on the medium into the second color reproduction range expressed in a device-independent color space using the first correction parameter. A computer is caused to function as a generation unit that generates a second correction parameter for correcting black and white so that a color value corresponding to white in the device corresponds to a white color value in the device-independent color space. . A program for performing color matching processing between devices having different color reproduction ranges by a computer,
The image data input from the first device and expressed in the device-dependent color space of the first device is converted into a device-independent color space representation, and the image data based on the color sample recorded on the medium is further converted. Monochrome correction is performed so that a color value corresponding to white in the first color reproduction range in which the color reproduction range of one device is expressed in the device-independent color space is associated with a white color value in the device-independent color space. First conversion means for black and white correction using a first correction parameter for
A color reproduction range obtained by converting the color reproduction range of the second device based on the color sample recorded on the medium into the second color reproduction range expressed in a device-independent color space using the first correction parameter. Using the second correction parameter for black and white correction so that the color value corresponding to white in the device corresponds to the white color value in the device-independent color space, the device-independent color space The image data converted into the image data is reversely corrected, and the computer is further functioned as second conversion means for converting the device-independent color space representation into the device-dependent color space representation of the second device. Program.

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