JP2003244460A - Image processor, image processing method, recording medium, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently realize a configuration for reproducing colors so that output images can be viewed in the same color tone. <P>SOLUTION: The image processor is provided with a means for generating a color conversion algorithm and a color conversion parameter on the basis of inputted color space information in the case of the color conversion from an input color signal to an output color signal and a color conversion means for converting colors by using the color conversion algorithm and the color conversion parameter. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing device, an image processing method, a storage medium and a program.

[0002]

2. Description of the Related Art In the conventional method for converting an input color image signal into an image signal in an output device, a photographic toning correction for outputting an image image or a text or graph image depending on the characteristics of the output image is used. Image quality after color correction such as graphics color correction that preferably outputs various business documents. Further, according to Japanese Patent Application Laid-Open No. 8-256275, in the conventional color correction processing, the purpose is to perform color mapping of the input color space information to the color reproduction color gamut information in the printer, so that there are several different color reproduction color gamuts. When color mapping is performed on the input color space, the color gamut mapping processing is performed on the input color space information and the color reproduction color gamut information individually according to a predetermined algorithm. When images are output to a plurality of output media by the same printer, the color gamuts that can be reproduced are different depending on the output media.

An image processing apparatus in a conventional example will be described below. FIG. 22 is a block diagram showing a schematic configuration of the image processing apparatus. 2101 is a CPU, and ROM2
Information data and control programs stored in 102,
A RAM 2103, an operation unit 2104, an image processing unit 21 according to an OS (operating system), an application program (hereinafter referred to as an application), a color matching processing module, a device driver, and the like.
05, monitor 2106, input device 2107, and output device 2108 are variously controlled. An input device 2107 inputs color space information data for which an arbitrary profile is desired to be created by an image reading device such as an image scanner including a CCD sensor or a color measuring device to a host computer. An output device 2108 outputs an image by an inkjet printer, a thermal transfer printer, a dot printer, or the like. The RAM 2103 is a work area and a temporary save area for various control programs and data input from the operation unit 2104. An operation unit 2104 is used to set the output device setting unit 2107 and input data. An image processing unit 2105 performs image processing including profile creation for converting an input color image signal by gamut mapping processing into an image signal in an output device. 2106
Is a monitor, and displays a processing result of the image processing unit 2105, data input by the operation unit 2104, and the like.

Next, a main image processing apparatus for creating a profile for converting an input color image signal into an image signal in an output device and its operation will be described below.
The block diagram shown in FIG. 23 shows the configuration of a profile creation device when mapping input information in an arbitrary input color space to an output color space.

Each device in the profile creating section 2201 will be described. 2209 and 2210 are terminals, and 22
Information regarding the color gamut of the printer that is the output device is input from 09, and input color space information that is information about the color gamut of the input device is input from 2210. An input color gamut storage device 2204 stores the input input color space information, and a reference numeral 2205 is a printer color gamut storage device and stores the color gamut information of the printer which is the input output device. 206 is a mapping parameter calculation device,
With reference to the printer color gamut information and the input color space information, a color space compression parameter required in the color gamut mapping device 2207, which will be described later, is calculated.

Reference numeral 2207 is a gamut mapping device, which refers to the input color space information and the printer color gamut information, and reproduces an image quality having a desired gradation with respect to the input information. Map the gamut of to the printer gamut.
Hereinafter, the mapping result will be referred to as a mapping color gamut. 220
Reference numeral 8 denotes a profile creation device, which has a correspondence relationship between an input color gamut and a mapped color gamut, input color information (RGB data) for outputting a predetermined color in the input color space, and a predetermined color on a printer. Output color information (C
MYK data) and a profile for conversion from input data to printer output element data is created. Then, the created profile is written in the RAM 2202. On the other hand, in the image processing device,
Reference numeral 212 denotes a terminal, and from 2211, RGB image data on the host computer is input to the interpolation device 2203. The interpolator 2203 refers to the profile stored in the RAM 2202, converts the RGB image data information into output element data, and passes it through 2212 to the output device.

The profile creating section 22 in the above configuration
The operation of 01 will be described. In this case, in the mapping operation of the profile creation unit 2201, the L * a * b * color space is used as the uniform color system.

First, in response to a command from the CPU 2101, the color gamut information of the input color space and the color gamut information of the printer are transmitted. The transmitted two color gamut information are stored in the input color space gamut storage device 2204 and the printer color gamut storage device 2205 in the profile creation unit 2201, respectively. Is stored as Next, the inside of the profile creation unit 2201 operates as follows. First, the mapping parameter calculation device 2206 operates to calculate various parameters required for color space compression in the color gamut mapping device 2207.
When the parameter calculation is completed, the gamut mapping device 220
7 operates to map the color gamut of the input color space to the printer color gamut in the uniform color system. The gamut mapping device 2207 performs the mapping operation according to the flowchart of FIG. 3, and this operation will be described in detail later. Next, the profile creation device 2209 creates a profile for converting input information into printer color information by referring to the mapping color reproduction area that is the final mapping result, and writes the profile in the RAM 2202. With that, a series of operations is completed.

The operation of the mapping process in the color gamut mapping device 2207 will be described below with reference to the flowchart of FIG. In this description, a continuous locus connecting a certain color and a certain color is called a gradation line.

First, at step 301, sample points for defining the mapping of the color gamut are determined. The sample points are divided into surface sample points that define the mapping of the surface of the input information color reproduction area and internal sample points that define the mapping inside the input information color reproduction area. Next, in step 302, where the surface sampling points are to be mapped in the printer color reproduction area is determined. Incidentally, the mapping result of the surface sample points is not always located on the surface of the printer color reproduction area. In step 303, a position in the printer color gamut for the internal sample point is determined. However, the mapping is controlled so that the mapping result of the internal sample points is always located inside the printer color gamut. Then, in step 304, a gradation line connecting two predetermined different surface sample points (hereinafter, surface gradation line) is defined. In step 305, where to map the surface gradation line to the printer color reproduction area is determined. The mapping result of the surface gradation line is not necessarily located on the surface of the printer color reproduction area. Then, in step 306, a gradation line connecting two predetermined internal sample points (hereinafter, internal gradation line).
Stipulate. In step 307, where the internal gradation line should be mapped in the printer color reproduction area is determined. The mapping is controlled so that the mapping result of the internal gradation line is always located inside the printer color reproduction area. Finally, in step 308, the mapping result from the input color space color gamut to the mapping color gamut for the color desired to express the mapping color gamut is acquired from the surface gradation line and the internal gradation line. To do.

Conventionally, in the mapping process, the Lab color space or the LCH color space, which is a uniform color space, is used.
In particular, when the hue of the input color signal is mapped onto the output color space, control is performed by the hue angle in the Lab color space or the LCH color space.

Furthermore, color correction processing by color gamut mapping processing is performed for the purpose of performing mapping processing on the color reproduction color gamut and input color space information on each output medium in a one-to-one relationship. Further, in the color correction processing, since the color correction processing is customized so as to obtain an appropriate color correction result in the photo color correction or the graphics color correction, the color correction processing or the color correction processing apparatus , Divided by the desired image quality.

[0013]

However, although the image based on the input color space data and the color reproduction gamut information subjected to the gamut mapping processing have similar color reproducibility to each other, an image having a similar color reproducibility can be obtained. There is a problem that the output images that have undergone the mapping process have different impressions. Therefore, in the same printer, in the output images when the output mediums are different, even if the input signals are the same, the output images do not appear to have the same reproduced tint.

This corresponds to the difference between different color reproduction gamuts and is output between different color reproduction gamuts only by approximating only a pair of relationships of input color space information and printer color reproduction space information. This is because the process of approximating the color of the image is not performed in the color correction.

The Lab color space and the LCH color space described above do not necessarily match the human visual characteristics, colors that appear to be the same color due to lightness are not on the same hue angle, and the same color saturation is used. The visible colors are not on the same hue angle.
Therefore, in the conventional color correction result using the same hue angle in the Lab color space or the LCH color space, an input color image signal is converted into an image signal in an output device, and an arbitrary color of an image output by the output device is converted. Regarding Col, reproduced hues vary. In particular, when the shapes between the color reproduction ranges are different, as a result of the mapping process, it is difficult to perform color reproduction so that the output images have the same tint.

Further, in the mapping process in color correction, although the basic mapping process steps are common as described above, in order to obtain a desired image quality, the parameters used in the mapping are used. And some of the mapping algorithms needed customization. Therefore, the color correction processing or the color correction device is divided, including the parameters and algorithms that can be shared. Therefore, it is inefficient even when a large storage capacity is required in the image processing apparatus, the apparatus also requires a desired number of image qualities, and the reproduced image quality in the printer is increased.

The present invention has been made to solve the above-mentioned problems, and in the color conversion for converting an input color signal into an output color signal, even if the shape of the color reproduction range is different, the color conversion is performed. The purpose is to perform a color conversion process that realizes color reproduction so that the results can be seen together.

The present invention has been made to solve the above-mentioned problem, and in color conversion for converting an input color signal into an output color signal, the input color space and the output color space are referred to and the output color space is set. Create the corresponding color conversion parameters,
Another object of the present invention is to perform a color conversion process that realizes color reproduction without color shift or variation when viewed by a person in different output color spaces by determining an algorithm and performing color conversion.

[0019]

[Means for Solving the Problems] As one means for solving the above problems and achieving the object, the present invention has the following configuration.

In the image processing apparatus of the present invention, in the color conversion for converting the input color signal into the output color signal, a means for generating a color conversion algorithm and a color conversion parameter based on the input color space information, and the color It is characterized by comprising a conversion algorithm and a color conversion means for performing color conversion using a color conversion parameter.

In the image processing method of the present invention, in the color conversion for converting the input color signal into the output color signal, a step of generating a color conversion algorithm and a color conversion parameter based on the input color space information, and the color It is characterized by having a conversion algorithm and a color conversion step of performing color conversion using a color conversion parameter.

The image processing recording medium of the present invention has a function of generating a color conversion algorithm and a color conversion parameter based on input color space information in color conversion for converting an input color signal into an output color signal, and It is characterized in that a program for realizing a color conversion algorithm and a color conversion function for performing color conversion using a color conversion parameter is recorded.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The outline and configuration of an embodiment of the present invention will be described with reference to the block diagram shown in FIG. Reference numeral 101 is a CPU, and ROM 102
Data, control programs, OS stored in
(Operating system), application program (hereinafter referred to as application), color matching processing module, device driver, etc.
The RAM 103, the operation unit 104, the image processing unit 105, the monitor 106, the input device 107, and the output device 108 are variously controlled. 107 is an input device, which is a CCD
Color space information data for which an arbitrary profile is desired to be created by an image reading device such as an image scanner including a sensor or a color measuring device is input to a host computer. An output device 108 outputs an image by an inkjet printer, a thermal transfer printer, a dot printer, or the like.
The RAM 103 is a work area and a temporary save area for various control programs and data input from the operation unit 104.
An operation unit 104 is used for setting the output device setting unit 107 and inputting data. 105 is an image processing unit,
The image processing unit 105 according to the gradation point information setting and the gamut mapping processing using the set gradation point information in the present embodiment.
Image processing including profile creation is performed. Reference numeral 106 denotes a monitor, which is a processing result of the image processing unit 105 and an operation unit 10.
The data and the like input in 4 are displayed.

Next, as shown in FIG. 2, in the mapping parameter calculation device 206 in the profile creation unit 201, even if the shape of the color reproduction range is different as a part of its function, the input color signal Parameters and algorithms for performing processing for making the color conversion results look uniform, and parameters and algorithms necessary for color correction processing for achieving desired image quality (hereinafter, these are collectively referred to as image design guideline data) are stored. It has an image design guideline data storage device 213. The image design guideline data storage device 213 is connected to a host computer and a network via a terminal 214, and can read and store image design guideline data that realizes a desired image quality. Further, in the image design guideline data storage device 213, a plurality of image design guideline data are stored, and the terminal 2
It is also possible to have a configuration in which the image design guideline data can be switched through 14 to execute the color correction processing desired by the user, according to an instruction from the user.

In the mapping parameter calculation device 206, mapping parameters necessary for mapping processing for realizing desired image quality are created based on the image design guideline data stored in the image design guideline data storage device 213. . In the mapping parameter calculation device 206,
In the mapping process, the conventional processing algorithm for realizing the desired image quality in the output gamut corresponding to the input gamut, the shared mapping parameter creation algorithm, or the mapping parameter creation algorithm expected to be used frequently 4, which is stored in advance in a mapping point determination program storage unit 408 and a mapping parameter creation program storage unit 409 of FIG. 4, which will be described later, and is defined as normal processing.

FIG. 4 shows a configuration for creating mapping parameters. Reference numeral 213 denotes an image design guideline data storage device that performs mapping processing in creating mapping parameters so that color conversion results for input color signals can be seen even if the shape of the color reproduction range is different. Therefore, data for creating necessary parameters and data for creating parameters for realizing desired image quality are stored. The mapping parameters refer to mapping point coordinates of surface sampling points in mapping processing, gradation characteristic control information of the output image, color space compression parameters for mapping internal sampling points, and the like.

In the present embodiment, the details of the mapping process for making the color conversion results for the input color signals look uniform even if the shape of the color reproduction range is different will be described later, but in the image design guideline data storage device 213. Is a parameter and algorithm for determining the mapping point of the surface sampling point that absorbs the difference in the shape of the color reproduction range. The mapping point determining parameters 401 and 402 are the mapping point determining program 1, the 403 is the mapping point determining program 2, and the like. Stored respectively. Similarly, mapping parameter creation parameter information 404 and mapping parameter creation programs 405 and 406 for calculating mapping parameters in the mapping process for determining the surface and internal mapping points from the input color space information and the output color space information. Etc. are stored. Of course, there is no limit to the number of parameters and algorithms. The program instruction information 407 manages the parameter creating process in the mapping parameter creating device 206, and appropriately transmits the program and parameters for creating mapping parameters in the image design guideline data storage device 213 to the mapping parameter creating device 206.

In the mapping parameter creation device 206, mapping parameter creation algorithms and parameters as normal processing are stored in the mapping point determination program storage unit 408 and the mapping parameter creation program storage unit 409. In the mapping parameter creation device 206,
When instructed to create each mapping point and mapping parameter,
Input color space information from the input color gamut storage device 204 is stored in the memory 412. In addition, the printer gamut storage device 20
5, the output color space information is stored in the memory 412.
The mapping point determination program or the mapping parameter creation program is appropriately selected from the normal processing and executed, but when there is an instruction from the program instruction information 407 in the image design guideline data storage device 213, the image design guideline is selected by the selector 410. The mapping point determination program or the mapping parameter creation program in the data storage device 213 is selected, and the memory 41 is selected in the processing unit 411.
Mapping points and mapping parameters are created with reference to the input color space information and the output color space information stored in 2, and stored in the mapping parameter storage memory 413.

Based on the image design guideline data stored in the image design guideline data storage device 213 of the present embodiment, the operation of the mapping parameter calculation device 206 will be described with reference to the flowchart shown in FIG.

First, in step 501, the input color space color gamut information and the printer color gamut information are stored in the input color space gamut storage device 204 and printer color gamut storage device 205 in the profile creation unit 201. It

In step 502, the image design guideline data stored in the image design guideline data storage device 213 is acquired. At this time, when a plurality of pieces of image design guideline data are stored, one is selected by an instruction from the user through the operation unit 104.

In step 503, based on the input color gamut information and the output color gamut information, the mapping point specified by the image design guideline data is calculated for the sample points in the input color gamut, and the mapping parameter calculation is performed. In the device 206, the mapping points required for the mapping process are created using the conventional process.

In step 504, the created mapping point is stored in the mapping parameter storage memory 413. In step 505, the mapping parameter specified by the image design guideline data is calculated based on the input color gamut information and the output color gamut information. Mapping parameters are created. In step 506, the created mapping parameter is stored in the mapping parameter storage memory 41.
3 is stored.

The switching operation of the mapping point determination processing according to the image design guideline data will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 6 shows that the mapping points determined in step 503 shown in FIG. 5 are created by the normal processing so that the mapping points necessary for the mapping processing are created by the algorithm specified by the image design guideline data. Points shall be classified as being created. Therefore, step 5 shown in FIG.
In 03, when a certain mapping point is created by normal processing, the operation when the image design guideline data has an instruction to use a creation algorithm for a predetermined mapping point will be described in detail below.

In step 601, when a certain mapping point is created, it is judged from the program instruction information 407 in the image design guideline data storage device 213 whether or not there is an instruction to change the creation algorithm. Step 6
If the creation algorithm is not changed in the determination of the predetermined mapping point in 01, the mapping point is created by the normal process as it is.

If there is a change in the creation algorithm in the determination of a predetermined mapping point in step 601, a sample point in the input gamut to be designed by the image design guideline data corresponding to the created mapping point is obtained in step 602. To do.

At step 603, various parameters necessary for mapping are acquired from the image design guideline data. In step 604, the algorithm required for mapping is acquired from the image design guideline data. In step 605, mapping point information such as mapping point coordinates for the sample point acquired in step 602 is calculated by the acquired image design parameter and algorithm.

In step 606, the calculated mapping point information is stored in association with the sample points acquired in step 602. In step 607, it is determined whether or not there are other sample points to be processed by the same algorithm, and if there are sample points, the processing from step 602 onward is repeated. In step 607, it is judged whether or not there is another sample point to be processed by the same algorithm, and if there is no sample point, the process returns to the normal mapping point determination process.

The switching operation of the mapping parameter determination processing according to the image design guideline data will be described with reference to the flowchart shown in FIG. In the flowchart shown in FIG. 7, regarding the mapping parameters determined in step 503 shown in FIG. 5 described above, mapping parameters required for mapping processing are created by normal processing, and mapping parameters are mapped by an algorithm specified by the image design guideline data. The parameters shall be classified as being created. Therefore, in step 505 shown in FIG. 5 described above, the operation in the case where the image design guideline data has an instruction to use a creation algorithm for a predetermined mapping parameter when creating a certain mapping parameter by normal processing will be described in detail below. Explained.

In step 701, when a certain mapping parameter is created, it is judged from the program instruction information 407 in the image design guideline data storage device 213 whether there is an instruction to change the creation algorithm. If there is no change in the creation algorithm in the predetermined mapping parameter determination in step 701, the mapping point is created by the normal process as it is.

If there is a change in the creation algorithm in the determination of the predetermined mapping parameter in step 701,
In step 702, the mapping parameter item to be designed by the image design guideline data corresponding to the mapping parameter to be created is acquired.

At step 703, various parameters necessary for creating mapping parameters are acquired from the image design guideline data. In step 704, the algorithm required for creating the mapping parameter is acquired from the image design guideline data. In step 705, depending on the image design parameters and algorithms obtained, step 702
Then, the mapping parameter information for the mapping parameter item obtained in is obtained.

In step 706, the obtained mapping parameter information is stored corresponding to the mapping parameter item. In step 707, it is determined whether or not there is another mapping parameter item processed by the same algorithm, and if there is a mapping parameter item, step 70
The processing from 2 is repeated. In step 707, it is determined whether or not there is another mapping parameter item to be processed by the same algorithm, and if there is no mapping parameter item, the process returns to the normal mapping point determination process.

By the above processing, regarding the determination of the mapping point and the mapping parameter with respect to the sample point, the normal processing and the image design guideline for realizing the desired image quality in the output gamut corresponding to the input gamut stored in advance. A desired image quality is realized by the data, and a mapping point and a mapping parameter for the sample point that absorbs the difference in the color reproduction range are determined.

Next, the operation of the gamut mapping processor 207 will be described. FIG. 8 shows the configuration of the gamut mapping process in this embodiment. In the gamut mapping processing device 207, in the mapping processing, a conventional mapping algorithm for realizing a desired image quality in the output gamut corresponding to the input gamut, a shared mapping algorithm, or it is expected to be frequently used. The mapping algorithm is stored in the mapping program storage unit 804 in advance and defined as normal processing.

Reference numeral 213 denotes an image design guideline data storage device, which internally uses the mapping point information and mapping parameters created in the mapping process to input the input color signal even when the shape of the color reproduction range is different. The data of the mapping algorithm for performing the mapping processing so that the color conversion results for the can be seen together is stored. Further, the gamut mapping processing device 20
The mapping algorithm in the mapping program storage unit 804 of No. 7 uses the mapping process shown in FIG. 3 to map the coordinates of the surface sample points to the determined mapping point coordinates and the gradation characteristic control information of the output image. On the basis of this, the mapping points at the sample points for which the mapping points have not been determined are determined, and the mapping points of the internal sampling points are determined based on the surface sampling point information and the color space compression parameter.

In the image design guideline data storage device 213, as an algorithm for realizing a desired image quality in the mapping process and absorbing the difference in shape of the color reproduction range,
A mapping point determination program 1 is stored in 802, and an image point determination program 2 is stored in 803. Of course, there is no limit to the number of algorithms. Mapping program instruction information 8
Reference numeral 01 manages the mapping process in the gamut mapping processor 207, and appropriately sends the mapping program in the image design guideline data storage device 213 to the gamut mapping processor 207.

In the gamut mapping processor 207, a mapping algorithm as a normal process is stored in the mapping program storage unit 804. When the color gamut mapping device 207 receives an instruction to perform each step in the mapping process,
Input color space information from the input color gamut storage device 204 is stored in the memory 812. In addition, the printer gamut storage device 20
5, the output color space information is stored in the memory 812.
The mapping program is appropriately selected from the normal processing and executed, but the image design guideline data storage device 213
When there is an instruction from the mapping program instruction information 801 in the above, the selector 810 selects the mapping program in the image design guideline data storage device 213, and the processing unit 811 selects the input color space information and the output color space information stored in the memory 812. The mapping processing is performed by referring to the mapping point information and the mapping parameter stored in the mapping parameter storage memory 813, and the mapping result is transmitted to the profile creating unit 208 to create the profile.

In the gamut mapping processing device 207, the gamut mapping processing by the normal processing is performed according to the process described with reference to the flow chart of FIG. 3, but the mapping algorithm by the image design guideline data in this embodiment is used. The switching operation will be described below with reference to the flowchart shown in FIG.

In step 901, the input color space gamut storage device 204 in the profile creating section 201.
The input color space color gamut information and printer color gamut information are stored in the printer gamut storage device 205. In step 902, the mapping process is selected according to the process described with reference to the flowchart of FIG.

In step 903, it is determined whether or not there is a mapping process instructed by the image design guideline data in processing the selected mapping process. If there is a mapping process instructed by the image design guideline data in step 903, the instructed mapping program is read from the image design guideline data in step 904.
If there is no mapping process instructed by the image design guideline data in step 903, the mapping program in the normal process stored in the mapping program storage unit 804 is selected as the mapping program in step 905.

In step 906, step 904
The mapping point information and the mapping parameter necessary for executing the mapping program acquired in (1) are read from the mapping parameter storage memory 413 and stored in the memory 412. In step 907, mapping processing is performed based on the acquired mapping program, mapping parameter, and mapping point information. In step 908, the mapping result is temporarily stored in the memory 412. In step 909, it is determined whether or not all mapping steps have been completed. If not completed, in step 910, the next mapping step is selected, and the processing from step 903 onward is repeated.

In step 909, if all the mapping processes have been completed, the mapping process ends, and the completed mapping result stored in the memory 412 is transmitted to the profile creating device 208.

Even when the mapping parameter calculation device 213 and the gamut mapping device 207 having the above-described configuration have different shapes of the color reproduction range, the mapping processing is such that the color conversion results for the input color signal can be seen in a uniform manner. By performing the mapping process with the data for creating the parameters necessary for performing the image and the data for creating the parameters for realizing the desired image quality, and the image design guideline data in which the mapping algorithm is stored, Even when the shape of the reproduction range is different, the color conversion processing in which the color conversion results for the input color signal appear uniform can be realized.

Regarding the image design guideline data, there are various mapping point determination processing, mapping parameter determination processing, and mapping algorithm for making the color conversion results for the input color signal appear to be uniform, but the image processing apparatus and processing of the present invention are provided. As long as the method and the program stored in the storage medium are in a form adapted to the configuration of the present embodiment, the difference in means and algorithm does not matter.

Further, if the image processing apparatus and the processing method of the present invention and the program stored in the storage medium are in a form adapted to the configuration of the present embodiment, the kind of image quality realized by the image design guideline data is selected. It doesn't matter.

The following is a detailed description of an example of the mapping process in which the color conversion results for the input color signals appear to be uniform in this embodiment. It should be noted that, in this process, the determination of the mapping point and the determination of the mapping parameter specified by the image design guideline data and the mapping algorithm are mixed, but unless otherwise noted, all the processes are based on the image design guideline data. In the configuration of the image processing apparatus described above, it is assumed that the processing is switched from the normal processing.

Here, FIG. 10 shows printer color gamuts 1002, 10 having two different color reproduction ranges and shapes on the HVC color space, which is a coordinate system showing a distribution of visually equidistant colors.
A cross-sectional view at a certain brightness of 03 is shown. In the HVC color space, the chromaticity points on the equihue line 1001 in a certain hue H are determined to be the same color in human vision. Therefore, the equal hue line 1001 and the printer color gamut 100
The intersections 1004 and 1005 at 2, 1003 are
Although the saturation to be reproduced is different, it looks the same in human vision. Therefore, by performing mapping processing based on the equi-hue line information in the HVC color space, it is possible to obtain colors that have the same tint even in different printer color gamuts.

The hue H of the mapping points on the printer color gamut is a hue value on the HVC space which is a coordinate system showing a distribution of visually equidistant colors, and each coordinate value on the HVC space and the printer. It is necessary to perform coordinate conversion with the Lab space which is the color reproduction gamut display coordinates. In such a mapping process, the parameter for determining the mapping parameter from the image design guideline data is not the value in the Lab space used in the normal mapping process, but the coordinate values in the HVC space with different color spaces. An algorithm for instructing a special value and performing coordinate conversion between each coordinate value in the HVC space and the Lab space is stored in advance in the image design guideline data. Therefore, when the mapping parameter is created, the color space conversion algorithm and necessary conversion information are read from the image design guideline data, and the color space conversion is executed.

The input color space information is the RGB color space, and the distribution of the surface sampling points in the RGB color space is Re
FIG. 12 shows the d surface as an example. FIG. 12 shows the color reproduction range on the RGB color space as White, Red, and Black.
Represents a cutting plane cut along a plane passing through the three points. The upper left point is White (255, 255, 255), and the lower left point is Black (0, 0, 0). The vertical axis represents (R, G, B) coordinates from (0,0,0) to (2
55, 255, 255).
Ri represents a surface sampling point on the Red surface, and the index i is a number assigned to this surface sampling point in order of increasing lightness. R ₆ corresponds to the primary color Red. In addition, Green surface, Blue surface, Cyan
On the surface, the Magenta surface, and the Yellow surface, index numbers are assigned to the sample points in the same manner as above.

Further, in FIG. 13A, the cross section of the Red surface of the printer gamut output by a certain output medium, which is indicated by the solid line, is superimposed on the cross section of the Red surface of the RGB space, which is indicated by the dotted line in FIG. It is a thing. On the other hand, FIG.
2 is an overlapping of the cross section of the Red surface of the printer gamut in an output medium different from the output medium shown in FIG. 13-1. In this way, the shape of the printer color gamut differs depending on the output medium, and the mapping result is greatly affected depending on whether the shape is close to the shape of the RGB input color gamut. Therefore, in the present embodiment, at least Red, Green, and
The overall compression processing of the printer gamut by approximating the output color space to the shape of the RGB input gamut as to the cross section of the printer gamut in the six hues of Blue, Cyan, Magenta, and Yellow, and the above Red,
Green, Blue, Cyan, Magenta, Y
The printer color gamut shape is adjusted by aligning the tint of the output color using the HVC color space value in determining the mapping point on the W-Col-Bk of Ellow, and the mapping using the adjusted printer color gamut is performed.

This processing will be described in detail with reference to the flowchart shown in FIG. Here, the processing on the Red surface shown in FIG. 12 will be described as a representative.
n, Blue, Cyan, Magenta, Yellow
The same processing is performed on each cross section of w.

In step 1101, W-Col-B on the input color gamut for adjusting the printer color gamut is used.
Determine surface sampling points on k. Here, as shown in FIG. 12, R1 to R11 are set as sample points on the Red plane.

In step 1102, the lightness to be mapped is determined for the lightness at the surface sample points.

As shown in FIG. 12, since the overall lightness of the printer color gamut and the overall lightness of the RGB color space are different, the lightness mapped at each sample point is changed to the lightness in the printer color gamut. The mapping lightness is set so as to match. The result of the set brightness at each surface sampling point is shown by R1'-R11 'in FIG.

In step 1103, step 11
02 based on the mapping lightness set for the sample point, and from the hue value on the HVC color space defined in the image design guideline data for the hue of Red in advance, the mapping point in the printer gamut with respect to the sample point Regarding hue, a mapping hue target area (isochromatic line information) in the printer gamut is set. Details of the processing in step 1103 will be described later.

In step 1104, the saturation of the mapping point in the printer gamut with respect to the sample point is weighted in the saturation direction in the mapping point so as to be the outermost point of the printer gamut in the mapping hue target area obtained in step 1103. decide. The weighting in the printer color gamut at each mapping point is 1 for the outermost contour point. Also,
When the saturation is weighted, it is assumed that the saturation is always mapped onto the corresponding mapping hue target area (isochromatic line information) for each mapping lightness obtained in step 1103. In step 1105,
Map the sample points to the printer gamut. Step 1
At 106, a surface gradation line including surface sample points is determined on the surface of the input color gamut.

In step 1107, the mapping of the surface gradation line is performed so as to include the mapping point in step 1104. In Step 1108, a Red cross section of the printer color gamut cut out by mapping the surface gradation line,
The shape of the red cross section in the input color reproduction area is compared.
The volume of the printer gamut that is lost from the original printer gamut due to the printer gamut being modified,
The degree of approximation with the shape of the input color space is compared, and it is determined whether the amount of volume lost is as small as possible and whether the shape of the input color space is as close as possible. If it is determined in step 1109 that the Red cross section of the printer color gamut cut out by the mapping of the surface gradation line and the Red cross section in the input color reproduction area are not sufficiently similar in shape, in step 1111 step 1104 is performed.
In, the weighting in the saturation to which each sample point is mapped is adjusted so as to approximate the shape with the Red cross section in the input color gamut, and the processing from step 1105 is repeated.

If it is determined in step 1109 that the Red cross section of the printer color gamut cut out by the mapping of the surface gradation line and the Red cross section in the input color reproduction area are sufficiently similar in shape, in step 1110. , The Red cross section of the printer color gamut that is cut out by the mapping of the surface gradation line is set as the color space area for mapping.

The above processing is performed at least for Red and Gre.
en, Blue, Cyan, Magenta, Yell
By performing this on the ow section, the color reproduction range based on the printer color gamut cut out by the mapping of the obtained surface gradation line is sufficiently close to the input color reproduction range. Therefore, even if the printer gamuts of different shapes on different output media are adjusted to a color gamut that is sufficiently close to the input color gamut, and at least Red, Green, Blue, Cya are adjusted by the image design guideline data.
The hues of n, Magenta, and Yellow that are mapped are based on the HVC color space, and are mapped to the chromaticity points of the tint that looks the same to human eyes.

Therefore, at least Red, Green, Blue, Cyan, and M for the printer color gamut adjusted so as to be sufficiently approximated to the input color gamut in this processing.
Since the tint of the mapping points in “agenta” and “Yellow” is approximated, and in determining the other mapping points, the mapping point is determined by referring to the previously mapped chromaticity point, so that it is within the input color reproduction range. Even if the mapping is performed on the other sample points by the conventional method, it is possible to sufficiently arrange the color reproducibility of the color conversion results using the printer gamuts of different shapes on different output media.

The printer color gamut adjusted by the above processing is shown by the solid line in FIG. The mapping result in the adjusted printer color gamut is shown in FIG. continue,
According to the flowchart shown in FIG. 16, based on the mapping lightness set for the surface sampling points in step 1103 described above, and regarding the hue for the surface sampling points in advance on the HVC color space defined in the image design guideline data. The process of setting the mapping hue target area (isochromatic line information) in the printer gamut for the hue of the mapping point in the printer gamut with respect to the sample point will be described in detail. Here, FIG. 16 shows the lightnesses to be mapped at the surface sample points R1-R11 for the Red cross section of the printer gamut as L1-L11, respectively.

In step 1601, input color space information and output color space information are acquired. Step 1602
At, the lightness number counter for setting the equal hue line information is set. In step 1603, the mapping target lightness Ln is selected. In step 1604, the target hue value of the designated color of the sample point at the lightness to be mapped is acquired. The target hue value is stored in advance in the image design guideline data, and the hue information for each color is set in the memory area as shown in FIG.

FIG. 19 shows an example of the structure of the target hue value data memory. FIG. 19 shows an example of the configuration of the hue information data memory. Regarding the memory areas 1901 to 1906 that store the hue information for each color, Red, Green, Blue, and Cy for sample points, respectively.
Predetermined target hue values when hues of an, Magenta, and Yellow are designated are stored in advance. The target hue value is a hue value in the HVC color space in which the lightness, the hue, and the saturation are uniformly changed with respect to human eyes. Here, each target hue value is shown and stored as the hue H in the Munsell color space. Further, for convenience, W-R ₆ -B on the surface of the input color space in FIG.
The mapping point of the surface sampling point Ri moving on the k gradation line has the same mapping hue. Of course, even if the mapping hues are different for Ri, the memory area for storing the hue information for each color as shown in FIG.
It is also possible to retain the data in which the corresponding hue value is stored as to the target hue value and to obtain the hue that is suitable for the color reproduction for realizing the monitor match image quality in the lightness to be mapped as the target hue value.

In this step, the Munsell hue value 5R, which is the designated hue value for Red, is read from the stored memory area 1201 and acquired as the target hue value. Therefore, in the present embodiment, the Munsell color space is defined as the HVC space for obtaining the equal hue line for each lightness, and the coordinate points of the Munsell color space and the Lab color space are associated with the image design guideline data. Information is stored,
Based on the target hue value and the image brightness information, the equal hue line data for each image brightness is set. Here, the hue storage data memory has a configuration in which a target hue value can be designated and registered for an arbitrary designated color of the user or an arbitrary sample point of the user in the gamut mapping device 207. May be Reference numerals 1907 and 1908 and later are memory areas in which hue values specified by the user can be registered and deleted. Data that stores the hue value of the color specified by the user as the corresponding hue value is registered for the sample point arbitrarily specified by the user, and the user desires the mapping point of the sample point specified by the user. It becomes possible to map to a hue value.

In step 1606, equal hue line information is set so as to obtain a coordinate point that achieves the target hue value from 0 to saturation so as to cover the printer color gamut.

With respect to the equal hue line setting target lightness selected in step 1605, the target hue value in the equal hue line setting target lightness is realized on the HVC color space, and the equal hue line information changing in the saturation direction is converted into the HVC color space. From the reference data,
Obtained as HVC color space coordinate values. At this time, the equal hue line information may be information of continuous coordinate points (segments) or may be obtained as some discrete coordinate point information. In the present embodiment, the latter form has equal hue line information. The obtained uniform hue line information HVC color space coordinate values are converted into Lab data and stored in the memory 412.

FIG. 21 shows an example of the equal hue line data storage memory area in the memory 412 for storing the equal hue line data set in this embodiment. The data memories 2101, 2109, and 2110 are a set of Lab coordinate data representing the equal hue line setting lightness and the equal hue line at L * = L1, L2, and L11, respectively.

The index at the left end in 2102-2108 is a number assigned in ascending order of saturation with respect to the equal hue line when obtaining the equal hue line, and the ab coordinate points on the corresponding equal hue line are stored respectively. To be done.

At step 1607, the printer color reproduction area information and the equal hue line setting object lightness obtained at step 1606 are obtained in order to obtain the coordinate point that realizes the target hue in the contour of the printer color reproduction area at the equal hue line setting object lightness. The coordinates of the intersection of the contour of the printer color gamut and the equal hue line are calculated from the equal hue line information in the memory 41.
Store in 2.

At step 1608, since the coordinates of the intersection of the contour of the printer color reproduction area and the equal hue line at the target lightness are obtained, the value of the division number counter is decremented.
In step 1609, the counter value of the lightness number to be mapped is checked. If the counter number is 0, in step 1610, the coordinate points and the equal hue line information for realizing all the target hue values in the contour of the printer color gamut for all the equal hue line setting lightnesses are calculated.
All the calculated coordinate points are stored in the gradation point data memory 414, and the processing according to this flow ends.

An example of the intersection coordinate data memory area in the memory 412 for storing all the intersection coordinates calculated in FIG. 20 is shown. In this figure, for each specified color,
The coordinates of the intersection of the contour of the printer color gamut and the equal hue line are stored for each mapping brightness. The equal hue line data memory 1301 in the Red data shown in FIG. 12 in the equal hue line data memory area has the RGB shown in FIG.
The mapping point coordinates in the Lab space at the sample points R1 to R11 and the points W and Bk which are the input data are stored.

If the counter value of the mapping lightness counter is not 0 in step 1609, the process returns to step 705 and the coordinates of the isochromatic line for the remaining lightness to be mapped and the coordinates of the intersection with the isochromatic line in the outline of the printer color gamut. To calculate. FIG. 11 shows a result of obtaining the above-mentioned equal hue line information. The vertical axis represents the lightness axis, and the plane coordinate axes are the orthogonal coordinate axes a * axis and b * in the Lab uniform color system, respectively.
It is an axis. The printer color gamut is indicated by the solid line. W-
Lightness L1 to L on the line indicated by the dotted line between Bk
n is the divided lightness information in the above processing, and the equal hue line information for each lightness that reproduces the Munsell hue 5R in Red associated with the lightness information L1 to Ln is indicated by a dotted line.

The outline of W-Red-Bk in the printer color gamut shown in FIG. 11 and the intersection of the equal hue line information indicated by the dotted line are indicated by black circles, and W-Re
A cross-sectional view of a region surrounded by a contour of d-Bk and a gray line of W-Bk is shown. W to Bk
The row of black circles on the outline of W-Red-Bk toward the arrow is the actual intersection coordinates, and the chromaticity obtained based on the HVC space in which the lightness, hue, and saturation change are even with respect to the human eye. It is a point. In contrast to the chromaticity points indicated by the black circles, the chromaticity points on the iso-hue line at the equal lightness indicated by the white circles appear to have a different saturation in terms of the same color to the human eye. Therefore, when the color space is corrected along the equal hue line in the adjustment of the printer gamut in the flowchart shown in FIG. 11, the tint of the mapping point is
It will be saved.

As described above, by performing the mapping processing according to the processing flow in FIG. 3 using the color gamut of the printer color space newly determined according to the present embodiment, the shape distortion of the printer color gamut at the time of mapping is performed. It is possible to reduce the influence on the output image due to, and the input signal is associated with the corresponding point of the hue H to the printer color gamut so as to have the same tint as the human eye. Therefore, even if the color gamuts are different from each other, it is possible to map to the chromaticity points of the printer color gamut that looks like the same color visually, and the output color spaces are in a similar relationship. Therefore, the color reproducibility between the images output by using different color reproduction areas can be made uniform at the impression level.

Other Embodiment 2 <Storage Medium> The present invention can be applied to a system composed of a plurality of devices (for example, host computer, interface device, reader, printer, etc.) It may be applied to a device (for example, a copying machine, a facsimile device, etc.) that is a device.

Another object of the present invention is to supply a storage medium having a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to supply the computer (or CPU) of the system or apparatus.
Needless to say, this is also achieved by the MPU) reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, C
A D-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a ROM, etc. can be used.

Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) running on the computer based on the instruction of the program code. It is needless to say that this also includes the case where the above) performs a part of the actual processing and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted in the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

[0092]

As described above, according to the present invention, in the color conversion for converting the input color signal into the output color signal, a desired image quality is realized in the input color space and the output color reproduction range, and the output is performed. It has image design guideline data that stores the algorithms and parameters necessary to absorb the difference in shape between the color reproduction ranges, and the target color signal based on the image design guideline data and the color signal information corresponding to the visual characteristics. By performing color conversion using and, it is possible to perform color conversion processing that realizes color reproduction with a uniform color tone, regardless of the difference in shape of the color reproduction range when viewed by a person.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an image processing apparatus commonly used in an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an image processing apparatus of the present invention.

FIG. 3 is a flowchart showing the flow of processing in the color gamut mapping device of the present invention.

FIG. 4 is a block diagram showing a configuration of an image processing apparatus of the present invention.

FIG. 5 is a flowchart showing the flow of processing in the present invention.

FIG. 6 is a flowchart showing the flow of processing in the present invention.

FIG. 7 is a flowchart showing the flow of processing in the present invention.

FIG. 8 is a block diagram showing a configuration of an image processing apparatus of the present invention.

FIG. 9 is a flowchart showing the flow of processing in the present invention.

FIG. 10 is a diagram showing a relationship between printer color gamuts in the HVC color space according to the present invention.

FIG. 11 is a flowchart showing the flow of processing in the present invention.

FIG. 12 is a diagram showing an example of input color space data of the present invention.

FIG. 13 is a diagram showing a relationship between an input color space and a printer color gamut according to the present invention.

FIG. 14 is a diagram showing an example of the mapped lightness of the present invention.

FIG. 15 is a diagram showing a processing result according to the present invention.

FIG. 16 is a flowchart showing the flow of processing in the present invention.

FIG. 17 is a diagram showing a processing result according to the present invention.

FIG. 18 is a diagram showing a processing result according to the present invention.

FIG. 19 is a diagram showing an example of a memory area according to the present invention.

FIG. 20 is a diagram showing an example of a memory area according to the present invention.

FIG. 21 is a diagram showing an example of a memory area according to the present invention.

FIG. 22 is a block diagram showing a configuration of a conventional image processing apparatus.

FIG. 23 is a block diagram showing a schematic configuration of a conventional image processing apparatus.

[Explanation of symbols]

101 CPU 102 ROM 103 RAM 104 Operation Unit 105 Image Processing Unit 106 Monitor 107 Input Device 108 Output Device 201 Profile Creation Unit 202 RAM 203 Interpolator 204 Input Color Gamut Storage Device 205 Printer Color Gamut Storage Device 206 Mapping Parameter Creation Device 207 Color Gamut Mapping device 208 Profile creation device 209 Terminal 210 terminal 211 Terminal 212 terminal 213 Image design guideline data storage device 214 Terminal 401 Mapping point determination parameter information 402 Mapping point determination program 1 403 Mapping point determination program 2 404 Mapping parameter creation parameter information 405 Mapping Parameter creation program 1 406 Mapping parameter creation program 2 407 Program instruction information 408 Mapping point determination program storage unit 409 Mapping parameter creation Program storage unit 410 Selector 411 Processing unit 412 Memory 413 Mapping parameter storage memory 801 Mapping program instruction information 802 Mapping program 1 803 Mapping program 2 804 Mapping program storage unit 805 Search processing unit 806 Interpolation processing unit 1001 Hue line 1002 Printer color gamut 1003 Printer gamut 1004 Chromaticity point 1005 Chromaticity point 1901 Red Target hue storage memory 1902 Green Target hue storage memory 1903 Blue Target hue storage memory 1904 Cyan Target hue storage memory 1905 Magenta Target hue storage memory 1906 Yellow Target hue storage memory 1907 User setting Color target hue storage memory 1908 User set color target hue storage memory 2001 Gradation point data storage memory 2101 L * = L1 etc. Phase line data storage memory 2102 Isochromatic line ab coordinate storage memory 2103 Isochromatic line ab coordinate storage memory 2104 Isochromatic line ab coordinate storage memory 2105 Isochromatic line ab coordinate storage memory 2106 Isochromatic line ab coordinate storage memory 2107 Isochromatic line ab Coordinate storage memory 2108 Isochromatic line ab coordinate storage memory 2109 Isochromatic line data storage memory 2110 at L * = L2 Isochromatic line data storage memory at L * = L11

Continued front page    F-term (reference) 2C087 AA03 AA09 AA15 AB01 AB05                       AC05 AC07 BD24 BD36                 2C262 AA02 AA03 AA07 AB11 BA01                       BA03 BA09 BB03 BC13 BC15                       BC17 BC19 CA07 CA10 EA12                 5B057 BA02 BA26 CA01 CA08 CA12                       CA16 CB01 CB08 CB12 CB16                       CE17 CE18 CH07 CH18                 5C077 LL19 MP08 PP35 PP36 PP37                       PP68 PQ12 TT02                 5C079 HB06 HB08 HB11 LA02 LB02                       MA11 NA03 NA29 PA03

Claims (20)

[Claims] 1. In a color conversion for converting an input color signal into an output color signal, a means for generating a color conversion algorithm and a color conversion parameter based on the input color space information,
An image processing apparatus comprising: the color conversion algorithm and a color conversion unit that performs color conversion using a color conversion parameter. 2. The color conversion means includes a color signal calculation means for calculating a color signal using the color conversion algorithm and color conversion parameters, and a means for storing color gamut information of an output device that outputs the output signal. The image processing apparatus according to claim 1, further comprising: a mapping color signal calculating unit that calculates a mapping color signal from the calculated color signal and the stored color gamut information. 3. The image processing apparatus according to claim 1, wherein the color conversion parameter includes conversion information of a certain color value or gradation characteristic conversion information between two certain color values. 4. The image processing according to claim 1, wherein one of the color conversion algorithms is selected from a plurality of algorithms defined in advance based on the input color space information. apparatus. 5. The color conversion parameter according to claim 1, wherein one is selected from a plurality of parameters defined in advance based on the input color space information. The image processing device according to item 1. 6. The image processing apparatus according to claim 1, wherein the color conversion algorithm includes target color signal designation for designating a target color signal. 7. The image processing apparatus according to claim 1, wherein the color conversion parameter includes target color signal designation information for designating a target color signal. 8. The conversion information of the certain color value or the gradation characteristic conversion information between the two certain color values in the color conversion parameter is color space information different from the color space in the input color space information. The image processing device according to claim 1 or 2, wherein 9. The parameter and algorithm are for performing processing for making the color conversion results for input color signals look uniform even when the shape of the color reproduction range is different. The image processing device according to item 1. 10. In a color conversion for converting an input color signal into an output color signal, a step of generating a color conversion algorithm and a color conversion parameter based on the input color space information, the color conversion algorithm and the color conversion. An image processing method, comprising: a color conversion step of performing color conversion using a parameter. 11. The color conversion means comprises: a color signal calculation means for calculating a color signal using the color conversion algorithm and a color conversion parameter; and a means for storing color gamut information of an output device which outputs the output signal. 11. A mapping color signal calculating means for calculating a mapping color signal from the calculated color signal and the stored color gamut information.
The described image processing method. 12. The image processing method according to claim 10, wherein the color conversion parameter includes conversion information of a certain color value or gradation characteristic conversion information between two certain color values. 13. The image according to claim 10, wherein one of the color conversion algorithms is selected from a plurality of algorithms defined in advance based on the input color space information. Processing method. 14. The color conversion parameter is selected from a plurality of parameters defined in advance based on input color space information.
The image processing method according to claim 10. 15. The image processing method according to claim 10, wherein the color conversion algorithm includes target color signal specification for specifying a target color signal. 16. The image processing method according to claim 10, wherein the color conversion parameter includes target color signal specification information for specifying a target color signal. 17. The color space conversion information of the certain color value or the gradation characteristic conversion information between the two color values in the color conversion parameter is different from the color space in the input color space information. The image processing method according to claim 10 or 11, wherein 18. The parameter and algorithm are for performing processing for making the color conversion results for input color signals look uniform even when the shape of the color reproduction range is different. Item 10. The image processing device according to item 10. 19. In a color conversion for converting an input color signal into an output color signal, a code for generating a color conversion algorithm and a color conversion parameter based on the input color space information, the color conversion algorithm and the color conversion. A recording medium for recording a program having a code for color conversion using parameters. 20. In color conversion for converting an input color signal into an output color signal, a code for generating a color conversion algorithm and a color conversion parameter based on the input color space information, the color conversion algorithm and the color conversion. A program having a color conversion code for performing color conversion using parameters.