JP2002064721A - Medium having profile generating program recorded thereon, profile generator, profile generation method and medium with profile data recorded thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent spread of the width of a pit formed due to a beam spot by controlling a recording pulse when the diameter of the beam spot is large than the pit desirably to be formed and to improve the accuracy of a reproduced signal. SOLUTION: Coordinate data as a reference color given in advance in a prescribed color space and image data as to the reference color received via an image input device are acquired, and a profile generating means suitable for each position in the prescribed color space is used to generate a profile on the basis of the reference color coordinate data and the input image data. Thus, profile with high accuracy with and at the outside of a color reproduction range can be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a medium recording a profile creation program, a profile creation device, a profile creation method, and a medium recording profile data.

[0002]

2. Description of the Related Art When a color input by an input device of a computer is output by an output device, each device operates such that the output color is reproduced as the same color as the input color regardless of the characteristics inherent to the device. ICC (International C
(Color Consortium) standards are being adopted. In the ICC standard, each input / output device is provided with profile data for providing a correspondence between a colorimetric value of a color chart and image data, and the image data of each input / output device is set to a reference through the profile. Color development independent of each device is performed by being associated with a certain colorimetric value.

In creating a profile, a reference color chart usually provided with a plurality of color patches is measured by a colorimeter to obtain a colorimetric value as a coordinate value in a predetermined color space. Further, the reference color chart is input to the input device to obtain the image data. These colorimetric values and image data correspond one-to-one, but since the number of the color patches is smaller than the number of profile data, a profile of a color other than the reference color is created from both. Here, as a conventional method of creating a profile for the input device, there are mainly two types of methods.

One of them uses a so-called interpolation operation. Considering the relative relationship between a certain image data value and the surrounding input image data, a similar relative relationship is established in the color space. The coordinate value is obtained, and the color of the coordinate value is associated with the value of the image data. Another technique uses a so-called matrix operation. In the same method, a matrix that gives the colorimetric values of the reference color chart by the product of the input image data is considered, and a matrix using the least squares method or the like using all of the colorimetric values and input image data Is determined, and a profile is created based on the relationship determined by the matrix.

[0005]

The above-described conventional image processing has the following problems. Since the above interpolation calculation uses the surrounding colors to create a profile for a certain color, local accuracy in the color space is good,
The conversion accuracy of the profile is good within the color reproduction range of the color chart. When the interpolation calculation is applied to the outside of the color reproduction range, so-called extrapolation is performed, so that the conversion accuracy deteriorates.
On the other hand, since the above matrix operation considers the entire reference color,
Although high local accuracy cannot be expected, a profile can be created without extremely deteriorating accuracy as a whole.

As described above, the above two methods cannot create a highly accurate profile inside and outside the color reproduction range. The present invention has been made in view of the above problems, and has a medium, a profile creation device, a profile creation method, and profile data recording a profile creation program capable of creating a highly accurate profile inside and outside a color reproduction range. The purpose is to provide the media.

[0007]

According to one aspect of the present invention, there is provided a profile creation program for creating a profile for providing a correspondence between input color data of an image input device and predetermined color space coordinates. And a reference color coordinate data acquisition function for acquiring coordinate data for a reference color given in advance in the predetermined color space, and a function for acquiring the reference color input through the image input device. A profile for creating a profile based on the reference color coordinate data and the input image data using a reference color input data acquisition function for acquiring image data and a profile creation method suitable for each position in the predetermined color space The configuration is such that a computer realizes the creation function.

[0008] In the invention according to claim 1 configured as described above, a profile is created by using a plurality of profile creation methods instead of using a single profile creation method. Here, as the profile creation method, a method suitable for each position in the predetermined color space is selected. Therefore, the conversion accuracy of the profile does not decrease at a specific position in the color space, and the accuracy does not reach a certain level over the entire color space.

As described above, the invention according to claim 2 is a preferred example for specifying a position in a color space when a profile creation method suitable for each position in a color space is used. 1. In the medium recording the profile creation program described in 1, the profile creation function includes a profile creation method suitable for a color space within the color gamut of the input reference color and a profile creation method suitable for a color space outside the reference color gamut. The configuration is such that a profile creation method suitable for a color space can be used. In the invention according to claim 2 configured as described above, since a profile creation method suitable for each of the inside and outside of the color reproduction range of the reference color is used, high accuracy can be achieved only within the color reproduction range, or color reproduction can be performed. There is no such thing as to achieve only a certain degree of accuracy overall within and outside the range. Here, the color reproduction range of the reference color is also referred to as a color gamut. When the color chart with the color patches is measured by a colorimeter to obtain the coordinate data of the reference color, the color chart of the color chart is used. The reproduction range is the color reproduction range of the reference color here.

[0010] Various methods can be adopted as the profile creation method. As an example, the invention according to claim 3 is based on a medium in which the profile creation program according to claim 1 or 2 is recorded. The profile creation function is a first profile creation method for creating a profile from a local relationship in the color space between the coordinate data of the reference color and the input image data, and the coordinate data of the reference color and the input image data. And a second profile creation method for creating a profile from the relationship in the entire color space with the above.

In the invention according to claim 3 configured as described above, in the first profile creation method, a profile is created from a local relationship in the color space between the coordinate data of the reference color and the input image data. Therefore, profile conversion can be locally performed with high accuracy. Here, creating a profile from a local relationship refers to executing profile conversion with reference to a value in a color space that is closer to the coordinate data of the reference color and the input image data. At this time, if it is within the color reproduction range of the reference color, the coordinate data exists at a short distance in the color space, and it can be said that the conversion accuracy within the color reproduction range is high. Outside the color reproduction range, the coordinate data does not exist at a close point in the color space, and the profile conversion accuracy is reduced.

On the other hand, in the second profile creation method, a profile is created from the relationship between the coordinate data of the reference color and the input image data in the entire color space. Profile can be created with a precision of. Therefore, it can be said that the conversion accuracy is higher in the second profile creation method than in the first profile creation method outside the color reproduction range. In this sense, the second profile creation method is used outside the color reproduction range. It can be said that it is suitable for. In this way, by adopting different profile creation methods inside and outside the color gamut, high-precision profile conversion is realized in most parts of the color space, and profile conversion is performed without loss of accuracy in the remaining parts. It can be performed.

Various methods can be adopted as the first profile creation method. As an example, in the invention according to claim 4, in the medium recording the profile creation program according to claim 3, In the first profile creation method, a profile is created by interpolation calculation based on the correspondence between the coordinate data of the reference color and the input image data. In the invention according to claim 4 configured as described above, the first profile creation method creates a profile by interpolation calculation. That is, considering the relative relationship between a certain image data value and the surrounding input image data, a coordinate value having a similar relative relationship in the color space is obtained by interpolation, and the color of the coordinate value and the color of the image are calculated. Correlate with the data value. Therefore, the image data can be locally associated with the coordinates in the color space with high accuracy.

Various methods can be adopted as the second profile creation method. For example, in the invention according to claim 5, the profile creation method according to any one of claims 3 and 4 is provided. In the medium on which the program is recorded, the second profile creation function creates a profile using a matrix calculated using the correspondence relationship between the reference color coordinate data and the input image data in the entire color space. There is a configuration. In the invention according to claim 5 configured as described above, in the second profile creation method, a profile is created by matrix operation. That is, consider a matrix that gives the colorimetric values of the reference color chart by the product of the input image data, and determine the matrix using the least square method or the like using all of the colorimetric values and the input image data. Then, a profile is created based on the relationship determined by the matrix. Therefore,
The image data can be associated with the coordinates in the color space with a certain degree of accuracy for the entire color space.

As described above, in the present invention, the profile creation method suitable for each position in the color space is used. However, it is possible to prevent the profile creation method from changing suddenly at the boundary of the space position. Can also. As an example of a configuration for this purpose, in the invention according to claim 6, in the medium on which the profile creation program according to any one of claims 2 to 5 is recorded, the profile creation function is provided outside the color reproduction range. The configuration is such that a profile is created near the boundary while superimposing the first profile creation method and the second profile creation method at a gradually changing overlap ratio. That is, the profile creation method does not suddenly change at the boundary. Here, the superimposition ratio should be changed gradually so as not to change the profile creation method suddenly.
It suffices that at least a portion where the overlapping ratio between the two is not “0” exists near the boundary between the inside and outside of the color reproduction range.

Of course, the recording medium described above may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium to be developed in the future. Also, the duplication stages of the primary duplicated product, the secondary duplicated product, and the like are equivalent without any question. Although different from the above-described medium, if the supply method is performed using a communication line, the communication line is used as a transmission medium and the present invention is used. Further, even when a part is implemented by software and a part is implemented by hardware, the concept of the present invention is not completely different, and a part is stored on a recording medium and appropriately It may be in a form that can be read.

As described above, in creating a profile, the method of changing the creation method for each region of the color space is realized by a substantial computer, and in this sense, the present invention is applied to a substantial computer including such a computer. It can be easily understood that the present invention is also applicable as a device. That is, there is no difference that the present invention is effective as a substantial device controlled by a computer. Therefore, the invention according to claims 7 to 12 basically has the same operation. Of course, the idea of the invention is not limited to this, and may include various aspects, and may be implemented alone or may be implemented together with another method while being incorporated in a certain device. Can be changed as appropriate.

When such an image processing program proceeds with the processing in accordance with such control, it is natural that the invention exists in the procedure at the root thereof, and it can be applied as a method. Easy to understand. Therefore, the invention according to claims 13 to 18 has basically the same operation. That is, there is no difference that the method is not necessarily limited to a substantial medium or the like and is effective as a method.

The profile data created as described above is referred to when the input device is used, and the color of arbitrary input data can be made to correspond to the predetermined color space coordinates with high accuracy. Here, this profile data has a characteristic in its data structure in the sense that it is created by the above method, and according to the invention according to claim 19,
High-precision color conversion can be performed without creating a profile by using a colorimeter or the like.

[0020]

As described above, according to the first, seventh, and thirteenth aspects of the present invention, the conversion accuracy of a profile at a specific position in a color space is reduced, It is possible to create a high-accuracy profile inside and outside the color gamut without preventing a certain degree of accuracy. According to the second, eighth, and fourteenth aspects of the present invention, high accuracy is achieved only within the color reproduction range, or only a certain degree of accuracy is obtained outside the color reproduction range. There is no. Further, according to the third, ninth, and fifteenth aspects of the present invention, high-precision profile conversion is realized in most parts of the color space, and profile conversion is performed in the remaining parts without deteriorating accuracy. It can be carried out.

Furthermore, claim 4, claim 10, and claim 1
According to the sixth aspect, image data can be locally associated with coordinates in the color space with high accuracy.
Furthermore, according to the fifth, eleventh, and seventeenth aspects of the present invention, it is possible to associate image data with coordinates in the color space with a certain degree of accuracy at a position where local accuracy cannot be obtained. . Further, according to the inventions according to the sixth, twelfth, and eighteenth aspects, the profile creation method does not suddenly change at the boundary of the color reproduction range. Further, according to the nineteenth aspect, it is possible to perform high-precision color conversion without creating a profile if only the medium is prepared.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view showing a hardware configuration of a profile creation system according to an embodiment of the present invention, and FIG. 2 is a block diagram of a main part thereof. In the figure, a scanner 40 is connected to a computer 10 via a USB cable.
1 is connected to the computer 10 via a parallel cable.

The scanner 40 includes a light emitting diode (not shown) and an image sensor (not shown).
Image data represented by the three primary colors B is generated and output. This scanner 40 performs scanning,
The light emitting diode emits light while moving, and irradiates a scanning target such as a color chart placed on the scanning surface with irradiation light. The image sensor moves and detects the reflected light from the scan target. Based on an output signal from the image sensor, pixel data in which each of the three primary colors of RGB is displayed in 256 gradations is generated. You.

In the present embodiment, a color chart 42 conforming to the ANSI standard is used to create an ICC profile. Since color charts of the same standard include a reflective original and a transparent original, the same profile can be created even when the scanner 40 is configured to scan a transparent original. Of course, other color charts can be adopted, but the above-mentioned ANSI standard compliant product has an appropriate number of colors, and the colors are appropriately dispersed within the color gamut that can be reproduced by the scanner 40, and are easily available. It is preferable from the viewpoint of the above. Although the scanner 40 is a preferred example of the input device, the present invention is not limited to such a configuration, and can be applied to profile creation of various image data input devices such as a digital camera.

The colorimeter 41 is provided with a spectrophotometer provided with two-dimensional freedom of movement on the mounting surface of the color chart 42, and based on an output signal of the spectrophotometer, CIE xyz of each color patch. It outputs coordinate values (XYZ values) in the color system. That is, by moving the spectrophotometer on the mounting surface of the color chart 42 and scanning each color patch, the coordinate value of each color patch of the color chart 42 in the absolute color space can be obtained. Of course, a color chart of a transparent original can be used here, and a color chart other than the ANSI standard can be used in the sense of creating a profile.

The colorimeter 41 is used to obtain the coordinate values of the color patches of the color chart 42 in the absolute color space. It is preferred to use However, in consideration of the fact that the color chart 42 conforms to a predetermined standard, by providing the XYZ values for the color patches on a floppy (registered trademark) disk or the like, a user who does not have the colorimeter 41 can register the profile. It can also allow you to create. In the colorimeter 41, not only colorimetry in the XYZ space but also Lab
The colorimetric space may be converted after the colorimetry of the space is performed, or a space other than the XYZ space may be used as the reference space if a profile that does not conform to the ICC standard is created.

On the other hand, the computer 10 is provided with a CPU 11 which is a center of arithmetic processing, and this CPU 11 is connected to a ROM such as a BIOS via a system bus 12.
13 and RAM 14 are accessible. Also,
A hard disk drive 15, a floppy disk drive 16, and a CD-ROM drive 17 as external storage devices are connected to the system bus 12, and an operating system (OS) 20, an application (APL), and the like stored in the hard disk drive 15 are provided. Is transferred to the RAM 14, and the CPU 11
The software is executed by appropriately accessing the AM 14.
In the present embodiment, the profile creation program can also be transferred from the hard disk drive 15 to the RAM 14 and executed.

An input device for operating a keyboard 31 and a mouse 32 is connected to the serial communication I / O 19a, and a display 18 for display is provided via a video board (not shown).
Is also connected. Further, the scanner 40 is a US
It can be connected via the B I / O 19b, and can be connected in parallel with the colorimeter 41 via the parallel communication I / O 19c. Although the configuration of the computer 10 has been described in a simplified manner, a personal computer or a workstation having a general configuration can be employed.

Of course, the computer to which the present invention is applied is not limited to a personal computer.
This embodiment is a so-called desktop computer, but may be a notebook computer or a mobile computer. The connection interface between the computer 10, the scanner 40, and the colorimeter 41 is also a USB I / O 19
b or the I / O 19c for parallel communication.
Various connection modes such as E1394 connection can be adopted, and the same applies to any connection mode developed in the future.

In this example, the types of programs constituting the profile creation program are the hard disk drive 1
5, but the recording medium is not limited to this. For example, it may be a floppy disk 16a or a CD-ROM 17a. The programs recorded on these recording media are read by the computer 10 via the floppy disk drive 16 and the CD-ROM drive 17 and are stored in the hard disk drive 1.
5 installed. Then, the data is read into the RAM 14 via the hard disk drive 15 to control the host computer. The recording medium is not limited to this, and may be a magneto-optical disk or the like. In addition, a non-volatile memory such as a flash card can be used as a semiconductor device, and even when an external file server is accessed and downloaded via a modem or a communication line, the storage unit of the computer serves as a recording medium. Needless to say.

FIG. 3 is a block diagram showing a configuration of a main part for executing profile creation in the computer 10. In the figure, a scanner driver 21 is incorporated in the OS 20 of the computer 10, and the scanner driver 21 controls the scanner 40 via the USB I / O 19b. When the scanner 40 is driven under the control of the scanner driver 21, the RGB pixel data output from the scanner 40 is input via the USB I / O 19b, and the scanner driver 21 outputs
The data is stored in the hard disk drive 15 as a GB data file 23. Each color patch of the color chart 42 is associated with an alphabet such as “A1” or “L12” and a number. In the RGB data file 23, stored data is associated with the color patch. While storing.

The OS 20 also includes a colorimeter driver 22
The colorimeter driver 22 controls the colorimeter 41 via the parallel communication I / O 19c. When the colorimeter 41 is driven under the control of the colorimeter driver 22, the coordinate values in the absolute color space output from the colorimeter 41 are input via the parallel communication I / O 19c, and the colorimeter driver 22 Is to store the data as an XYZ data file 24 in the hard disk drive 15. In addition, XYZ data file 2
4 also stores the stored data while associating the stored data with the color patches of the color chart 42.

In the present embodiment, the RGB
When the profile creation module 25 is executed with the data file 23 and the XYZ data file 24 stored in the hard disk drive 15, the IC
A profile conforming to the C standard is created and stored in the hard disk drive 15 as an ICC profile 26. Here, the profile creation module 25 further includes an interpolation operation module 25a and a matrix operation module 25b. As will be described in detail later, the interpolation calculation module 25a can calculate coordinate values in the Lab space corresponding to arbitrary RGB values and further convert the coordinate values into coordinate values in the XYZ space. The calculation is performed by interpolation and extrapolation. When the RGB values for which a profile is to be created are within the color reproduction range of the color chart 42, the interpolation is performed and the color is calculated. If it is out of the reproduction range, extrapolation is executed. In the present embodiment, the XYZ values of the interpolation points are obtained based on the four reference points. However, it is needless to say that this interpolation calculation method can employ other methods, such as eight-point interpolation. You can also do it.

Although the matrix operation module 25b will be described later in detail, the RGB data file 23
The matrix can be calculated based on the data stored in and the XYZ data file 24. This matrix is a 3 × 3 matrix that gives XYZ values by multiplying the matrix having RGB values as components. Further, it is possible to calculate a coordinate value in the XYZ space corresponding to an arbitrary RGB value using the matrix. The profile creation module 25 is composed of the interpolation calculation module 25
The upper ICC profile 26 is created using one or both of the correspondence between the RGB values and the XYZ values calculated by the matrix operation module 25b. The actual IC
The RGB values stored as the C profile 26 are uniformly 32 gradations for each color, that is, 36768 points in total.

When arbitrarily image data is captured by the scanner 40, an arbitrary RGB value output by the scanner 40 is converted into an absolute color space in an XYZ space by executing an interpolation operation with reference to the ICC profile 26. Corresponds to coordinate values. Therefore, if the printer or the display uses the profile conforming to the ICC standard, the color of the scanned image, the display display color, and the print color become substantially the same as long as the scanner 40 uses the ICC profile 26. Of course, at this time, the colorimeter 41 is no longer necessary. FIG. 4 is a block diagram showing an example of a configuration for performing a scan using the ICC profile 26. In the figure, the computer 10 has the same configuration as a normal personal computer used for the above profile creation, and when the computer 10 uses the scanner 40, the ICC profile 26 is used.
Is referred to.

An APL 27 is installed in the computer 10, and a user drives the scanner 40 by instructing an image capturing operation at the APL 27 to obtain desired image data. At this time, OS 20 is APL
ICM (Image)
(Color Management) 28. The ICM 28 converts input data and output data from each device into an XYZ value while referring to a corresponding profile, and is a CMM (Color Management).
Module) 28a (Applica)
Tion Program Interface).

That is, when an image capture is instructed by the APL 27, the scanner 40 is driven under the control of the scanner driver 21, and predetermined RGB data is input via the USB I / O 19b. Then, ICM2
Eight CMMs 28a refer to the ICC profile 26 to determine XYZ values corresponding to the RGB data, and color output on a display or a printer is performed based on the XYZ values. Therefore, the color data of each device is always handled via the XYZ values which are values in the absolute color space, and colors having no device dependency or OS dependency are handled as substantially the same color.

Hereinafter, a processing flow when a profile is created in the computer 10 having the above configuration will be described with reference to FIG. In step S100, the colorimeter 41 is driven under the control of the colorimeter driver 22, and the XYZ values of each color patch of the color chart 42 are acquired. Therefore, the processing in step S100 constitutes the reference color coordinate data acquisition function. FIG. 6 shows an example of the color chart 42 conforming to the ANSI standard.
As shown in the figure, the color chart 42 is provided with a large number of square color patches. Each color patch is mainly divided into a color area having saturation and an achromatic color area.
In the color area having saturation, 12 of “AL” are set in the vertical direction.
Color patches are provided in a grid pattern of 22 columns “1 to 22” in rows and in the horizontal direction.

In these chromatic color patch areas, color patches are further arranged based on different guidelines. In the same area, "1-12" column is "1-4" column,
It can be divided into three blocks of "5-8" columns and "9-12" columns. In each of these blocks, the brightness is different, that is, the colors in the same block are on the same plane in the Lab space. Also,
The column direction indicates a change in saturation. For example, in columns “1 to 4”, the saturation increases from “1” to “4”, and “4” indicates the saturation level of the saturation in the color chart 42. There is a certain color.

On the other hand, the row direction in the three blocks indicates a change in hue. That is, the change in the “AL” row indicates a circumferential color change in the Lab space in 12 steps. Further, in the “13 to 19” columns, CMY
Each color of KRGB (cyan, magenta, yellow, black, red, green, and blue) is shown, and each color is shown in the row direction with 12 levels of lightness. Also,
The achromatic color area is provided below the chromatic color area, and the brightness of the achromatic color is gradually changed in the area.

In step S100, the acquired XYZ values of the respective colors are stored in the row codes of "AL" and "1-2".
The data is stored in the XYZ data file 24 while being identifiable by the column code of "2" or the like. In step S102, the scanner 40 is driven under the control of the scanner driver 21, and the RGB values of each color patch of the color chart 42 are acquired. Therefore, the process in step S102 constitutes the reference color input data acquisition function. even here,
The acquired RGB values of the respective colors are represented by the above-mentioned “A to L” row codes,
The above RGB while being identifiable by column codes of “1 to 22”, etc.
It is stored in the data file 23.

Next, processing for creating a profile in association with RGB values and XYZ values is sequentially executed.
In order to consider the color reproduction range of the color chart 42, it is convenient to consider the color patches of the color chart 42 in the Lab space. Therefore, it is assumed that the Lab values are finally converted to the XYZ values. Perform interpolation and matrix operations. Therefore, in step S103, the XYZ values acquired in step S100 are converted to Lab values. In step S104, the matrix operation module 25
b is started, and a 3 × 3 matrix connecting the two is calculated by the least squares method based on the RGB data file 23 and the converted Lab values.

Here, the matrix is given by the following equation (1).

(Equation 1) The method of the least-squares method for calculating the matrix shown in the equation (1) is conventionally known in various ways, and thus the details are omitted, but the norm of the residual r shown in the following equation (2) is minimized What is necessary is just to obtain such a matrix.

(Equation 2) According to the matrix calculated in this way, high conversion accuracy in a local part of the color space cannot be expected, but it is possible to perform conversion while securing a certain degree of accuracy over the entire color space, and to some extent in the XYZ space. Accuracy can be ensured.

In step S106, it is determined whether or not the RGB values for which the ICC profile 26 is to be created are within the color reproduction range of the color chart 42. Here, the RGB values to be created have 32 gradations uniformly for each color as described above, and are the RGB values as shown in FIG. In the following, this R
The GB value is called a reference point. In this embodiment, the reference point is the color chart 42
Is determined based on a predetermined determinant. Here, each R in the RGB data file 23
The GB value corresponds to the identification code of the color chart 42 such as “A row 1 column”, and each XYZ of the XYZ data file 24
Since the value also corresponds to the same identification code, the Lab value converted in step S103 also corresponds to the identification code,
Each RGB value in the RGB data file 23 can be represented as a grid point in the Lab space. FIG. 8 shows the arrangement in the Lab space of each color patch of “A1 to L4” in the color chart 42.

In the same figure, the grid points "A1 to L4" in the hatched area have the same brightness, so that Lab
Located on the same plane in space. Incidentally, in FIG.
Although “L13 to L15, L17 to L18” are shown around “L4”, the brightness of the L rows in the columns “13” to “19” is lower than the brightness of the color patches “A1 to L4”. . Therefore, the lattice points of “L13 to L15, L17 to L18” are not necessarily on the same plane as the lattice points of “A1 to L4”.

Similarly to the "A1 to L4" blocks, the "A5
Also, for the colors of the blocks "-L8" and "A9-L12", grid points are formed on the same plane having the same brightness in the Lab space, and the grid points of the blocks "A5-L8" are located above the plane shown in FIG. A plane is located, and further above that, "A9
The grid point plane of the “〜L12” block is located. FIG. 9 shows L
It shows a half surface on the cyan side when the ab space is cut at a hue angle in the cyan direction. In the figure, “A13 to L1
As shown in "3", cyan constituting 13 columns of the color chart 42 constitutes a grid point on the outer side in the cyan direction in FIG. 9, that is, a point having the highest saturation in each brightness.
A grid point located outside the b-space is configured. FIG.
The straight line in the vertical direction on the right is a grid point of an achromatic color patch. Such a plane is similarly formed in the MYRGB direction, and the grid points of the color patches of the color chart 42 form a solid that is rotated around the achromatic straight line in FIG. The inside of the solid surrounded by the lattice points is the color reproduction range.

In order to determine whether or not the reference point is within the color reproduction range, it is sufficient to determine whether or not there is a reference point in a solid surrounded by the grid point. Here, by connecting grid points of the same lightness, the same hue, and the same saturation in a solid indicating the color reproduction range, the solid can be divided into a pentahedron, a hexahedron, and the like.
For example, “H1” and “H5” on the cyan surface shown in FIG. 9 are connected to “I1” and “I5” on the adjacent hue surface and the achromatic lattice point, and the pentahedron shown in FIG. To form Further, on the outside, "H1, H2, H5,
H6-I1, I2, I5, I6 "form a hexahedron. By cutting the diagonal of the squares that make up these pentahedral and hexahedral surfaces, the pentahedron is
It can be divided into three tetrahedrons as shown in FIG. 1A, and the hexahedron can be divided into five tetrahedrons as shown in FIG. 11B.

In any case, the solid constituting the color gamut can be regarded as a set of a plurality of tetrahedrons. Therefore, determining whether or not a reference point exists inside any of these tetrahedrons is equivalent to determining whether or not the reference point is within the color reproduction range. Whether or not a point exists in a certain tetrahedron can be obtained by a simple determinant using coordinates in a three-dimensional space.

In the tetrahedron shown in FIG. 12, the coordinates of each vertex are a, b, c, and d, and the coordinates are a (R
a, Ga, Ba), b (Rb, Gb, Bb), c (R
c, Gc, Bc) and d (Rd, Gd, Bd). The following equation (3) is used for such a coordinate point.

(Equation 3) Is calculated, the sign of the value is the vertex a
And other vertices b, c, and d.

Specifically, if the sign is positive, the vertex b,
The arrangement of c and d is clockwise as viewed from vertex a, and if the sign is negative, the arrangement of vertices b, c and d is counterclockwise as viewed from vertex a. The absolute value indicates the volume of the tetrahedron. Thus, according to the above determinant, it is possible to determine on which side of an arbitrary triangle an arbitrary point is located. On the other hand, a necessary and sufficient condition for the point p (Rp, Gp, Bp) to exist in the tetrahedron is that the point p is always on the same side as the remaining vertex with respect to the triangle formed by each vertex of the tetrahedron. That is.

Therefore, the following equation (4)

(Equation 4) It is determined whether or not the point p is on the same side as the vertex a by the determinant shown in the following. Similarly, the relationship with respect to the faces adc, abd, and acd is also determined. It is determined whether or not. As a result, when it is determined that the point p is on the same side as each vertex in all cases, the point p exists in the tetrahedron.

Since the color reproduction range is a set of a plurality of tetrahedrons as described above, in step S106, the reference point is set to the point p, and the determinant shown in equation (4) is calculated for all tetrahedrons. To go. As a result, when it is determined that the point p exists in any tetrahedron,
It is assumed that the reference point is within the color reproduction range. If it is determined in step S106 that the reference point is within the color reproduction range, a Lab value corresponding to the reference point is obtained by interpolation in step S108, and stored in the RAM 14. This stored Lab value is later converted to an XYZ value, and
As shown in (1), a profile in which the RGB values are associated with the XYZ values is created.

In the interpolation at step S108, the Lab value for the point p shown in FIG.
And the vertex abcd, and the volume ratio is used as a weight as a guideline. Specifically, using the following equation (5), the coordinates (Lp,
Ap, Bp).

(Equation 5)

In the equation (5), wa is the volume of the tetrahedron pbdc on the opposite side of the vertex a, and is the absolute value of the calculation result of the equation (4). Similarly, wb, wc, and wd are vertices b, c, and d obtained by the same calculation as the above equation (4).
Is the volume of the tetrahedrons padc, padb, pabc on the opposite side. The volume wa decreases as the point p moves away from the vertex a. By using the volume ratio as a weight, the conversion point of the point p in the Lab space and the Lab values of the vertices a, b, c, and d are calculated. Is relative to RGB
This is similar to the relative relationship between the point p and the vertices a, b, c, d in the space. Accordingly, the Lab value corresponding to the reference point can be calculated by this calculation, and the corresponding relationship is stored in the RAM 14. Of course,
In addition to the volume ratio, the inverse weight of the distance between the vertices a, b, c, d and the point p can be used as the weight.

After performing the interpolation operation in step S108, it is determined in step S110 whether or not the association for all the reference points has been completed. In step S110, the association for all the reference points is determined. Step S10 until it is determined that the process has been completed.
The processing after 6 is repeated. On the other hand, when it is determined in step S106 that the reference point is not within the color reproduction range, the correspondence between the reference point and the Lab value is calculated using one or both of extrapolation and matrix operation. Which process to execute is Lab
It is determined based on the distance between the reference point in the space and the center point of the achromatic color axis, and the distance between the center point of the achromatic color axis and the outer surface of the color reproduction range.

Therefore, in step S112, a distance ratio ratio serving as a guideline is calculated based on the following equation (6).

(Equation 6)

In step S114, the value of the ratio is determined based on the calculation result of equation (6). When it is determined in step S114 that “ratio <L1”, extrapolation is performed in step S116 to associate the reference point p with its coordinate value in the Lab space. In step S114, “r
When it is determined that “atio ≧ L2”, the RGB value is substituted into the above equation (1) in step S120, and the Lab value of the calculation result is associated with the RGB value of the reference point p. In the above step S114, “L1 ≦ ra
If it is determined that tio <L2, the extrapolation value and the matrix value are superimposed on the basis of the following equation (7) in step S118.

Here, P1 is the above-described extrapolated interpolation operation value, and P2 is the matrix operation value.

(Equation 7) Thus, steps S116, S118, S1 are performed.
The relationship associated at 20 is the above ICC profile 2
6 is stored. Therefore, the above steps S104 to S104
The processing in step S120 constitutes the profile creation function.

FIG. 13 is a diagram for explaining the extrapolation calculation, and is a perspective view showing a color reproduction range in the Lab space. In the figure, the center axis of the color reproduction range is an achromatic axis, and its center point is o. Connecting the grid points forming the outer surface of the color gamut forms a large number of triangles as shown in the figure, and the straight line connecting the predetermined reference point p outside the color gamut and the center point o is the above-mentioned number. Intersects any of the triangles. Therefore, this intersection is defined as a point m, and La of the reference point p is calculated using the ratio of the distance from the center point o to the point m and the distance from the center point o to the point p.
Calculate the b value. That is, when the above equation (7) is calculated, the relative relationship between the reference point p and the intersection point m with respect to the center point is determined, and the relative relationship is reflected on the Lab value as in the following equation (8).

(Equation 8) When this equation (8) is calculated, the Lab value of the reference point p similar to the relative relationship between the point p, the point m, and the center point o in the RGB space is calculated, and the Lab value of the reference point p is calculated by extrapolation. Is calculated.

As described above, the extrapolation uses the value of one point on the outer surface of the color reproduction range to obtain the Lab of the reference point p.
The value is generated. Specifically, it is necessary to obtain the RGB value at the point m as a precondition for executing this operation. Therefore, first, a straight line connecting the reference point p and the center point o in the RGB space is considered, and a point m at which the straight line intersects the triangle on the outer surface of the color reproduction range formed by the lattice point in the RGB space is searched. As a result of this search, the ratio can be obtained based on the above equation (6). In addition, since the RGB value of the intersection point m is found from the search, the Lab value corresponding to the point m can be obtained by the same operation as the interpolation.

Since the point m obtained in this manner is based on the center point o and the reference point p in the RGB space, the obtained point m is also used in the Lab space between the center point o and the reference point p. It is not always on a straight line. However, a point on a triangle in Lab space is R
Since it is considered to be on the corresponding triangle even in the GB space, it can be said that the calculated point m in the Lab space does not significantly differ from the actual intersection, and the calculated point in the Lab space is Extrapolation is performed with m as the intersection. If the Lab value of this point m is used, the Lab of the reference point p is obtained by the above equations (6) and (8).
An extrapolation value of the coordinate value in the space can be obtained. Here, since the calculated point m in the Lab space is regarded as an actual intersection, it can be said that the accuracy of the interpolation calculation decreases when the reference point p is out of the color reproduction range. It can be said that the accuracy decreases.

That is why the present invention is applied to the above step S114.
Is determined, the matrix operation is performed when the reference point p is separated from the color reproduction range by a predetermined distance, the extrapolation operation is performed if the reference point p is within the predetermined distance, and the two are superimposed in the middle. As a result, highly accurate conversion can be realized in the entire color space. In any case, after the Lab value corresponding to the reference point p is obtained, the process proceeds to step S110. Step S1
When it is determined in step S10 that the calculations for all the references have been completed, the coordinate values in the Lab space calculated in steps S108, S116, S118, and S120 in step S122 and stored in the RAM 14 are represented by X
The ICC profile 26 is converted to coordinate values in the YZ space and associates the RGB values and the XYZ values shown in FIG.

The operation of each unit when creating the ICC profile 26 shown in FIG. 7 using the color chart 42 will be described below. The user creates a color chart 4 on the stage of the colorimeter 41 when creating the profile.
2 is set and the profile creation program is started. Then, in step S100, the program drives the colorimeter 41 by the colorimeter driver 22 to measure each color patch of the color chart 42 on the stage.
As a result, the XYZ values of each color patch are input to the computer 10 via the parallel communication I / O 19c, and the XYZ values are stored in the XYZ data file 24.

Subsequently, when the user sets the color chart 42 on the scanning surface of the scanner 40, step S1
In step 02, the scanner 40 is driven by the scanner driver 21 to scan each color patch of the color chart 42 on the scanning surface. As a result, the RGB value of each color patch is
It is stored in the GB data file 23. Step S10
In step 3, the XYZ values stored in the XYZ data file 24 are converted into Lab values. In step S104, the norm of the residual r of the above equation (2) is calculated from the RGB data and Lab data corresponding to these colors on a one-to-one basis. Find a matrix by minimizing.

Further, in step S106 and thereafter, in order to make the reference points correspond to the XYZ values, RGB (0,0,0) to RGB (255,25) shown in FIG.
5, 255), for each reference point. In step S106, the above equation (4) is calculated for one of the tetrahedrons constituting the color reproduction range with respect to the reference point to be processed, and whether or not the reference point exists in the tetrahedron is determined. Determine. This determination is sequentially performed for each of the tetrahedrons forming the color reproduction range. When it is determined that the reference point exists in any one of the tetrahedrons, an interpolation calculation is performed in step S108. As a result, the Lab value of the reference point is calculated based on the above equation (5) and stored as the ICC profile 26.

For the reference points outside the color reproduction range, either extrapolation or matrix operation or superposition of these is executed through the determination in step S114, and the Lab value of the reference point is calculated.
After calculating the Lab value for each reference point, that is, for all 32768 reference points, the determination in step S110 is performed, and the process proceeds to step S122.
Is performed, the Lab value is converted into an XYZ value, and the above IC
It is stored as the C profile 26. When the ICC profile 26 is created, when the scanner 40 is used with the computer configuration as shown in FIG.
The RGB data of the scanner 40 is XYZ by M28a.
The output color is correlated with the value, and the output color is always substantially the same as the input color when another output device performs some output.

As described above, in the present invention, the coordinate data of the reference color given in advance in the predetermined color space and the image data of the reference color input via the image input device are obtained, and A profile is created based on the reference color coordinate data and the input image data by using a profile creation method suitable for each position in the color space. Therefore, a highly accurate profile can be created inside and outside the color reproduction range.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a hardware configuration of a profile creation system.

FIG. 2 is a main block diagram showing a hardware configuration of a profile creation system.

FIG. 3 is a block diagram illustrating a configuration of a main part that executes profile creation.

FIG. 4 is a block diagram illustrating an example of a configuration for performing a scan using an ICC profile.

FIG. 5 is a processing flow when executing profile creation.

FIG. 6 is a diagram illustrating an example of a color chart.

FIG. 7 is a diagram showing an example of an ICC profile.

FIG. 8 is a diagram showing an arrangement in a Lab space of a predetermined color of a color chart.

FIG. 9 is a diagram illustrating a state in which a Lab space is cut at a hue angle in a cyan direction.

FIG. 10 is a diagram showing a pentahedron and a hexahedron formed in a color reproduction range.

FIG. 11 is a diagram showing a state in which a pentahedron and a hexahedron are divided into tetrahedrons.

FIG. 12 is a diagram showing a positional relationship between a point p and a vertex abcd of a tetrahedron.

FIG. 13 is a perspective view showing a color reproduction range in a Lab space.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Computer 11 ... CPU 12 ... System bus 13 ... ROM 14 ... RAM 15 ... Hard disk drive 16 ... Floppy disk drive 16a ... Floppy disk 17 ... CD-ROM drive 17a ... CD-ROM 18 ... Display 19a ... I / O for serial communication O 19b USB I / O 19c Parallel communication I / O 20 OS 21 Scanner driver 22 Colorimeter driver 23 RGB data file 25 Profile creation module 25a Interpolation operation module 25b Matrix operation module 26 ... ICC profile 27 ... APL 28 ... ICM 28a ... CMM 31 ... Keyboard 32 ... Mouse 40 ... Scanner 41 ... Colorimeter 42 ... Color chart

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B057 BA28 CA01 CB01 CE16 CE18 CH18 5C077 MM27 MP08 PP31 PP32 PP36 PP37 PP43 PQ08 PQ12 PQ22 PQ23 RR19 5C079 HB01 HB05 HB08 HB11 LA01 LA28 LB02 MA11 NA03 NA29

Claims (19)

[Claims] 1. A medium storing a profile creation program for creating a profile that gives a correspondence between input color data of an image input device and predetermined color space coordinates, wherein a reference given in advance in the predetermined color space is provided. A reference color coordinate data acquisition function for acquiring coordinate data for a color; a reference color input data acquisition function for acquiring image data for the reference color input via the image input device; A profile creation program for causing a computer to realize a profile creation function of creating a profile based on the reference color coordinate data and the input image data using a profile creation method suitable for each position Medium. 2. A medium in which the profile creation program according to claim 1 is recorded, wherein the profile creation function includes a profile creation method suitable for a color space within a color reproduction range of the input reference color. A medium storing a profile creation program, characterized in that a profile creation method suitable for a color space outside the color reproduction range of a reference color can be used. 3. A medium in which the profile creation program according to claim 1 or 2 is recorded, wherein the profile creation function is performed in a color space between the coordinate data of the reference color and the input image data. A first profile creation method that creates a profile from the local relationships of
A medium storing a profile creation program capable of executing a second profile creation method for creating a profile from a relationship between coordinate data of a reference color and input image data in the entire color space. 4. A medium in which the profile creation program according to claim 3 is recorded, wherein in the first profile creation method, a profile is calculated by interpolation based on a correspondence between coordinate data of the reference color and input image data. A medium storing a profile creation program characterized by creating a profile. 5. A medium in which the profile creation program according to claim 3 or 4 is recorded, wherein the second profile creation function uses a color between the coordinate data of the reference color and input image data. A medium on which a profile creation program is recorded, wherein a profile is created using a matrix calculated using a correspondence relationship in the entire space. 6. A medium in which the profile creation program according to claim 2 is recorded, wherein the profile creation function is configured to execute the first profile creation method near a boundary inside or outside the color reproduction range. A profile creation program for creating a profile while superimposing a profile and a second profile creation method at an overlapping ratio that gradually changes. 7. A profile creation device for creating a profile that provides a correspondence between input color data of an image input device and predetermined color space coordinates, wherein coordinates of a reference color given in advance in the predetermined color space are provided. Reference color coordinate data acquisition means for acquiring data; reference color input data acquisition means for acquiring image data for the reference color input via the image input device; and for each position in the predetermined color space. A profile creation device comprising: a profile creation unit that creates a profile based on the reference color coordinate data and the input image data using a suitable profile creation method. 8. The profile creation device according to claim 7, wherein the profile creation means includes a profile creation method suitable for a color space within a color reproduction range of the input reference color and a color of the reference color. A profile creation apparatus characterized in that a profile creation method suitable for a color space outside a reproduction range can be used. 9. The profile creation device according to claim 7, wherein said profile creation means includes means for locally storing coordinate data of said reference color and input image data in a color space. A first profile creation method that creates profiles from relationships,
And a second profile creation method for creating a profile from a relationship between the coordinate data of the reference color and the input image data in the entire color space. 10. The profile creating apparatus according to claim 9, wherein in the first profile creating method, the profile is created by an interpolation operation based on a correspondence between the coordinate data of the reference color and the input image data. A profile creation device characterized by the following. 11. The profile creation device according to claim 9, wherein the second profile creation means includes a coordinate space data of the reference color and an input image data in an entire color space. A profile creation device for creating a profile using a matrix calculated using a correspondence relationship. 12. The profile creation device according to claim 8, wherein the profile creation means includes a first profile creation method and a second profile creation method near a boundary inside and outside the color reproduction range. A profile creation device characterized in that a profile is created while superimposing a profile creation method on a gradually changing overlap ratio. 13. A profile creation method for creating a profile that provides a correspondence between input color data of an image input device and predetermined color space coordinates, wherein coordinates for a reference color given in advance in the predetermined color space are provided. A reference color coordinate data obtaining step of obtaining data; a reference color input data obtaining step of obtaining image data of the reference color input via the image input device; and for each position in the predetermined color space, A profile creation step of creating a profile based on the reference color coordinate data and the input image data using a suitable profile creation method. 14. The profile creation method according to claim 13, wherein the profile creation step includes a profile creation method and a reference color suitable for a color space within a color reproduction range of the input reference color. A profile creation method suitable for a color space outside the reproduction range. 15. The profile creation method according to claim 13 or 14, wherein the profile creation step includes a step of locally storing coordinate data of the reference color and input image data in a color space. A first profile creation method that creates profiles from relationships,
A second profile creation method for creating a profile from the relationship between the coordinate data of the reference color and the input image data in the entire color space. 16. The profile creation method according to claim 15, wherein in the first profile creation method, a profile is created by an interpolation operation based on a correspondence relationship between the coordinate data of the reference color and the input image data. A profile creation method characterized by the following. 17. The profile creation method according to claim 15, wherein in the second profile creation step, the coordinate data of the reference color and the input image data in the entire color space are used. A profile creation method characterized in that a profile is created using a matrix calculated using a correspondence relationship. 18. The profile creation method according to claim 14, wherein the profile creation step includes the first profile creation method and the second profile creation near a boundary outside and inside the color reproduction range. A profile creation method characterized in that a profile is created while superimposing a profile creation method with a gradually changing overlap ratio. 19. A medium recording profile data for providing a correspondence between input color data of an image input device and predetermined color space coordinates, a coordinate value recording area for recording the predetermined color space coordinate values,
A color data recording area for recording the color data of the image input device, and the values recorded in the coordinate value recording area and the color data recording area include the color reproduction range of the reference color. A profile created from a local relationship in the color space between the coordinate data of the reference color given in advance in the predetermined color space and the input image data of the reference color input via the image input device. And a correspondence relationship based on a profile created from a relationship in the entire color space between the coordinate data of the reference color and the input image data is provided to the outside of the color reproduction range of the reference color. A medium on which profile data to be recorded is recorded.