JPH09181926A - Color management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image output with high quality utilizing features of color reproduction conversion sets for image read/output. SOLUTION: The device is provided with color reproduction area control means 42-45 with different conversion characteristics and any of the color reproduction area control means 42-45 is selected for input color image data so as to utilize each feature to realize optimum color reproduction. For example, in the case of color images whose gradation is desirably not lost and whose hue is desirably unchanged regardless of gradation in existence in mixture, the area is designated and any optimum means at the inside and the outside of the area is selected among the color reproduction area control means 42-45. Thus, the image processing result with higher image quality is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing for outputting the image data of a color image input device by a color image output device so that the output image has approximately the same color reproduction as the image of the input device. The present invention relates to a color management device (hereinafter, referred to as CMD) for performing.

[0002]

2. Description of the Related Art For example, when a color image on a CRT created by computer graphics or a color image read by a color scanner is output by a color printer,
Since the color image generation side (color image input device) and the output side (color image output device) perform image processing by their own methods, for example, image data read from a color scanner can be read by a color printer. There is a problem that the color tone will be different even if the same color image is output. An example of image processing to improve this is JP-A-61-28.
It is disclosed in Japanese Patent No. 8690 and Japanese Patent Laid-Open No. 5-88589.

FIG. 2 shows an example of a difference in color reproduction area between a color display and a color printer. Dp indicates a color reproduction area of the color display, and Pp indicates a color reproduction area of the color printer. As shown in this figure, the general color printer cannot currently completely reproduce the color image data displayed on the display. Past CM
In order to solve this problem in S, it has been attempted to make the hues of the input image data and the output image data approximately equal to each other by using some color reproduction area conversion means. Currently, as the color reproduction area conversion method, there are conversion methods such as the color difference minimum method, the hue preservation method, and the gradation preservation method.

Some color reproduction area conversion algorithms will be described with reference to FIG. 3: (1) Dye minimum method If the input color image data is within the color reproduction area of the output color image device, it is converted as it is. Output color image data without adding. If the solid line of the solid graph shown in (1) of FIG. 3 is the three-dimensional color reproduction area of the output color image device when it is outside the area range, the input color image data of the white circle points The output color image data is converted to a black dot that is within the color reproducible range of the output color device and has the smallest color difference.

(2) Hue Preserving Method When the input color image data is within the color reproduction area of the output color image device, the input color image data is output as it is without conversion. If it is outside the area range, assuming that (2) in FIG. 3 is the three-dimensional color reproduction area of the output color image device, the hue is not changed with respect to the input color image data of the white circle points. Then, the output color image data is converted into black circle points which are the color reproducible range of the output color device. (3) Gradation storage method The color image data is converted into the color reproduction area of the output color image device so as to preserve the gradation of the input color image data. Therefore, (3) of FIG. 3 is the output color image device 3
If it is a three-dimensional color reproduction area, each black circle point, which is the color reproducible range of the output color device, is set so as not to change the gradation of the input color image data of the white circle first point and the white circle second point. Convert the output color image data. In order to maintain gradation, different colors do not become the same color on the input color image data, but all colors are converted to slightly different colors.

The advantages and disadvantages of each of the above variations are shown in Table 1 below.

[0007]

[Table 1]

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a high-quality image output that makes use of the respective characteristics of these color reproduction conversions.

[0009]

The CMD of the present invention holds all color reproduction conversion as a function, and is optimal for input color image data so as to make full use of the respective features or to supplement the bad points. The conversion means for realizing color reproduction is switched and used.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) If, for example, a part where the gradation is not disturbed or a color image where the gradation is good but the hue is not changed is mixed in one color image data, that area is designated. Optimal color reproduction area conversion means is selected for conversion inside and outside. As a result, higher quality image processing results can be obtained.

(2) In one color image data, for example, a portion where the gradation is not disturbed or a color image where the gradation is good but the hue is not changed is mixed,
In the image processing that specifies the area and selects and converts the optimum color reproduction area conversion means inside and outside the area, it is automatically judged whether the content of the color image data is a photograph or a character, and the optimum Performs color reproduction area conversion processing. Higher quality image processing results are automatically obtained.

(3) In one color image data, for example, a portion in which gradation is not disturbed or a color image in which gradation is good but hue is not changed is mixed depending on color or hue. In this case, the optimum color reproduction area conversion means for the color or hue is selected and converted. Higher quality image processing results are automatically obtained.

(4) In one color image data, color data occupying a very large area, color data occupying a very small area, and color data other than that, are extremely For color data occupying a large area, when it is desired to perform processing by the color reproduction area conversion means that does not change the hue, the color reproduction area conversion means is selected and converted according to the histogram frequency of the color data. Higher quality image processing results are automatically obtained.

(5) Depending on the contents of the color image data,
When you want to select the optimum color reproduction area conversion means from among multiple, automatically and sequentially switch the color reproduction area conversion means to output all color image data, and select the most suitable color reproduction area conversion among these. Select and convert the means. Higher quality image processing results can be obtained.

[0015]

【Example】

First Embodiment FIG. 1 is a front view showing the outer appearance of the first embodiment of the present invention. The CMD of the first embodiment of the present invention is 40. CM
Originally, D refers to an image processing system for approximating the output image data to the same color reproduction as the input image data.
The CMD of the present invention refers to, for example, a device incorporated in an image processing device as hardware, firmware or software. The computer 10 has a display device capable of displaying color image data on a CRT,
This is a device that can input and output color image data to and from the CMD 40, and is shown as one of the color image input devices for the CMD 40 in FIG. 1. Color image data read by the image scanner 20, which is another color image input device, can be output to the color output device via the CMD. Color image data taken by the still camera 30, which is another color image input device, can be taken into the CMD through a medium. Further, a device capable of taking in color image data processed by CMD is connected to the output side.

The computer 50 is a device capable of inputting / outputting color image data to / from the CMD 40, similar to the computer 10, and in FIG.
It is shown as one of the image output devices. The other color image output device is a color printer 60, and the other one is a color copying machine 70 having a printer function.

FIG. 4 shows the configuration of the CMD 40 shown in FIG. In FIG. 4, the CMD 40 is indicated as 40A in order to distinguish it from the other examples. In addition, a mode is shown in which image data is obtained from the computer 10 which is one of the color image input devices, color reproduction conversion is performed, and output to the color copying machine 70 which is one of the color image output devices. It was

In the first embodiment, the color image data previously read in a large capacity medium such as a hard disk or an optical disk in the computer 10 by some means is displayed on a CRT display, or a color output image is output via the CMD 40A. Output to the device and print out.
There is a problem in that the displayed image on the CRT display and the printout image have subtle differences in color tone due to the difference in their color reproduction characteristics. In order to solve this, there are several algorithms for interpolating the difference between the color reproduction areas of the input device and the output device. Three of them are explained above.

In FIG. 4, reference numeral 12 is a keyboard for giving control data to the computer 10 and the CMD 40A. The input of the keyboard 12 is decoded into a control signal by the computer 10, and the control signal for color reproduction conversion processing is output to the CMD 40A. 41
Is a profile of the CRT display used in the embodiment and conversion means using the profile. At this stage, each color image density value data of RGB is converted into the CIE XYZ coordinate system by the profile in consideration of the feature of the color reproducible area of the CRT display as usual. 46A is an operation display board for the operator to specify an area.

The operation panel surface of the operation display board 40A is shown in FIG. The operator uses the touch pen 2 to move the cursor on the input color image on the color display 1 or the touch pen 2 to move the cursor to the upper left corner and the lower right corner of an area 3 in the image data. The coordinates are designated, and what kind of characteristics the area has with respect to the color image data is designated by the key. For example, that area is the photography section. Alternatively, it is designation of an image quality mode such as a character portion.

Reference numeral 47A in FIG. 4 is a photograph / character for storing the address of the upper left corner and the address of the lower right corner of the designated area and the image quality mode (designated code) for each area. It is a copy designation area storage unit. 48A in FIG.
It is a switching signal generation unit for generating a switching signal by referring to the designated area stored in the photograph / character portion designated area storage unit 47A and its image quality mode. The switching signal from the switching signal generator 48A switches the selector 49, and the converted output of the color reproduction area converting means designated by the switching signal is selected and given to the color image output device 70. That is, the input color image data converted into the CIE XYZ space by 41 in FIG. 4 is used as the input data of the color reproduction area conversion means 42 to 45 in FIG. 4, and the input image data in the CIE-XYZ space is obtained by each conversion means. Is converted into YMCK image data. At this time, each of the plurality of color reproduction area conversion means 42 to 45 is a conversion means adopting the minimum color difference algorithm of Table 1 described above, a conversion means using hue preservation, or a gradation preservation algorithm. The conversion means used. Although the conversion by each algorithm has advantages and disadvantages depending on the conversion algorithm as described above, these characteristics are closely related to the image quality mode, and the optimum color reproduction region conversion is performed for each image quality mode. The algorithm is set. For example, when it is desired to retain the gradation of the photograph portion of the input image data, the operator inputs the area of the photograph portion and specifies the photograph mode. Then, the converted output of the color reproduction area converting means using the algorithm capable of automatically preserving the gradation of the photograph is selected and given to the output device 70.

Since the color reproduction area conversion means 42 to 45 are conversion means including the characteristics of the color reproduction area of the color image data output device 70 of FIG. 4 in any algorithm, the image quality mode designated by the operator is selected. The optimum color image data for the image is supplied to the color image output device 70.

FIG. 6 mainly shows the content of the switching processing of the color reproduction area converting means by the switching signal generating section 48A. First,
The address of the color image data input to the CMD 40A is compared with the address of the designated area stored in the photograph / character portion designated area storage 47A. That is, it is checked in which designated area the address of the image data is located (steps S1A to S4A). In the following, in parentheses, the word step will be omitted, and step N will be used.
o. Only symbols are shown. Then, the image quality mode corresponding to the designated area including the address of the image data is read from the photograph / character portion designated area storage 47A, is decoded in the output selection signal, and is given to the selector 49 (S5A ...
S8A). That is, the color reproduction area conversion corresponding to the image quality mode of the designated area including the address of the image data is selected from among the plurality, and the color image data converted by the selected color reproduction area conversion means is output by the output device S8A. Transferred to. The above processing is repeated until the input color image data is completed. According to the first embodiment, the operator can realize the color reproduction area conversion more suitable for the input image than the conventional CMD.

-Second Embodiment- FIG. 7 shows a CMD 40B of a second embodiment. This is the first
Similar to the embodiment, it constitutes the CMD 40 of the system of FIG. In the CMD 40A of the first embodiment, the operator inputs area information from the operation display section, whereas in the CMD 40B of the second embodiment, the image mode in which the input color image data contents are Is automatically determined. That is, the character / photo automatic determination unit 46B
Determines from the input color image data itself whether the content of the color image data read from the input color image device 10 is character data or photographic data, and which part of the color image data is a photograph. The image quality mode such as which part of the data is character data and its range (that is, area information) are automatically recognized. The determination result storage unit 47B stores the image quality mode and the air area information.
Reference numeral 48B is a switching signal generation unit for generating a switching signal with reference to the area information stored in the determination result storage unit 47B and the image quality mode thereof. Color reproduction area conversion means 42-
The functions of 45, switching signal generator 48B and selector 49 are substantially the same as those of the first embodiment.

FIG. 8 mainly shows a character / photograph automatic determination unit 46B.
The contents of the switching processing of the color reproduction area converting means by the switching signal generating section 48B will be shown. First, the color image data input to the CMD 40B is automatically recognized by the character / photo automatic determination unit 46B whether the content is a character portion or a photograph portion including the area, and the result of this automatic recognition is It is stored in the determination result storage unit 47B (S1B to S1).
3B). Then, based on the recognition result, the switching signal generator 48B gives a switching signal to the selector 49, selects a color reproduction area conversion among a plurality of color reproduction area conversions according to the image quality mode corresponding to this, and selects the selected color reproduction area conversion means. The input color image data is converted by (S4B to S8B). This process is repeated until the input color image data is completed. According to the present invention, it is possible to perform color reproduction area conversion more suitable for image data than the conventional CMD.

-Third Embodiment- FIG. 9 shows a CMD 40C of a third embodiment. This is also the first
As in the embodiment, the system CMD40 in FIG. 1 is configured. FIG. 6 is an internal configuration diagram of an embodiment of claim 3 of the CMD of the present invention. While the CMD 40B of the second embodiment automatically determines the character / photo, the CMD of the third embodiment
40C automatically recognizes what color each part of the input image has. The color determining unit 46C of the CMD 40C compares the color data input in advance with the read color image data, determines whether color image data of the same color exists in the input color image data, and determines the color image. The area existing in the data, that is, the area information is recognized.
The color / position data storage unit 47C stores data such as the recognized area and what color the area is. The switching signal generator 48C generates a switching signal by referring to the recognition area and its color data stored in the color / position data storage 47C. With this signal, for example, when it is desired to retain the gradation of the red portion having a certain density of the input image data, it is assumed that the color of the area recognized by the color determination unit 46C is recognized as the previous red color. It is possible to select and convert the color reproduction area conversion means using an algorithm capable of automatically saving gradation. The selector 49 is switched by the switching signal from the switching signal generator 48C, and the optimum color image data for the color detected by the color determiner 46C is output from the selector 49 to the color image output device 70.

FIG. 10 shows the contents of the switching processing of the color reproduction area converting means mainly by the color judging section 46C and the switching signal generating section 48C. First, the content of the color image data input to the CMD 40C is determined by the color determination unit 46C.
The density of the color including the area is automatically recognized, and the result of this automatic recognition is stored in the color / position data storage unit 47C (S1C to S3C). Then, based on the recognition result, the switching signal generating section 48C gives a switching signal to the selector 49, selects a color reproduction area conversion among a plurality of color reproduction area conversions according to the image quality mode corresponding thereto, and selects the selected color reproduction area conversion means. The input color image data is converted by and is output to the color image output device 70 (S
4C-S8C). This process is repeated until the input color image data is completed. The third embodiment makes it possible to perform color reproduction area conversion more suitable for image data than the conventional CMD.

Fourth Embodiment FIG. 11 shows a CMD 40D of the fourth embodiment. This also constitutes the CMD 40 of the system of FIG. 1 as in the first embodiment. Histogram creation unit 4 of CMD40D
6D creates a histogram for each color of the input color image data. That is, the color is detected and the frequency of appearance of the color is obtained. The detected color and its application frequency are stored in the frequency result storage unit 47D.
Stored in. The switching signal generator 48D generates a switching signal by referring to the color data and the frequency data stored in the frequency result storage 47D. This signal switches the selector 49. For example, for a color with a certain frequency or more, since it occupies a considerable area in the image data, when it is desired to retain the gradation, the gradation is automatically maintained by the magnitude of this frequency. A color reproduction area conversion means using an algorithm is selected and converted. Therefore, the optimum color image data can be output to the output device 70.

FIG. 12 mainly shows a histogram creating section 46D.
The contents of the switching processing of the color reproduction area converting means by the switching signal generating section 48D will be described. First, the color represented by the color image data input to the CMD 40D and the number of appearances of the same color are detected and counted by the histogram creation unit 46D (S3D1 to S3D3). Next, for one pixel of the input color image data, the level to which the frequency of the color data belongs is determined. In the case of this embodiment,
There are 3 levels. The threshold levels at this time are N and M, respectively (N <M). Therefore, it is determined what level the read image data is, and, for example, it has a very high frequency and occupies a large part of the entire image data, so that the influence on the entire image data is large, When it is desired to avoid changing the hue during the color conversion, if the frequency is M or more in this embodiment, the image data is subjected to the color reproduction area conversion processing using the hue storage algorithm. The output is performed and output to the output device 70 (S4D to S8C). This process is repeated until the input color image data is completed. This allows conventional CMD
Rather, it is possible to perform color reproduction area conversion more suitable for image data.

-Fifth Embodiment- FIG. 13 shows a CMD 40E of a fifth embodiment. This CM
The D40E automatically outputs once for the same input image data by a plurality of color reproduction area conversion means 42 to 45.
The operator operates the operation display unit 46E to select the selection data for designating the color reproduction area converting means which seems to be the best from the output result.
Enter more. As a result, the operator can output the optimum color image data to the output device 70 with respect to the input color image data.

FIG. 14 shows the contents of the switching processing of the color reproduction area conversion means of the CMD 40E. First, the color image data input to the CMD 40E is sequentially converted by the color reproduction area conversion means 42 to 45 having different processing contents, and is printed out (or CRT displayed) by the color image output device 70 (S3E1 to S3E4). The operator sees these output results and inputs selection data designating the color reproduction area converting means of the optimum output from the operation display section 46E to the CMD 40E (S3E5). This data is the selected data storage 47E.
Stored in. The switching signal generator 48E gives a signal for selecting the conversion output of the color reproduction area conversion means designated by the stored selection data to the selector 49, converts the input color image data and outputs it (printout / CRT display). )
(S1E to S8E). This process is repeated until the input color image data is completed. According to the fifth embodiment, it is possible to perform color reproduction area conversion more suitable for image data than the conventional CMD.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of an embodiment of the present invention.

FIG. 2 is a graph showing a color expression area Dp of a CRT display and a color expression area Pp of a printer.

FIG. 3 is a graph showing a color reproduction area of a color image output device.

FIG. 4 is a block diagram showing a configuration of a CMD 40A of a first embodiment used as the CMD 40 shown in FIG.

5 is an enlarged plan view of an operation display unit 46A shown in FIG.

FIG. 6 is a flowchart showing an outline of image data processing of the CMD 40A shown in FIG.

7 is a block diagram showing a configuration of a CMD 40B of a second embodiment used as the CMD 40 shown in FIG.

FIG. 8 is a flowchart showing an outline of image data processing of the CMD 40B shown in FIG.

9 is a block diagram showing a configuration of a CMD 40C of a third embodiment used as the CMD 40 shown in FIG.

10 is a flowchart showing an outline of image data processing of the CMD 40C shown in FIG.

11 is a block diagram showing a configuration of a CMD 40D of a fourth embodiment used as the CMD 40 shown in FIG.

12 is a flow chart showing an outline of image data processing of the CMD 40D shown in FIG.

13 is a block diagram showing a configuration of a CMD 40E of a fifth embodiment used as the CMD 40 shown in FIG.

14 is a flowchart showing an outline of image data processing of the CMD 40E shown in FIG.

[Explanation of symbols]

1: Two-dimensional display 2: Pen 3: Area 4,5: Input key 6: Mouse 10: Computer 11: CRT display 12: Keyboard 20: Scanner 30: Steel camera 50: Computer 60: color printer 70: color copying machine 42-45: color reproduction area conversion means

Claims (5)

[Claims] 1. A color management device for making color image data output from an image output device the same color as color image data input from an image input device, wherein a plurality of color image data from input color image data to output color image data are provided. Color reproduction area conversion means; area specification means for specifying a plurality of areas on the input color image data; conversion specification means for specifying the color reproduction area conversion means for each area; and color reproduction specified for each area Image data of area conversion means
A color management device characterized by comprising conversion setting means for switching to digital conversion. 2. The color management device according to claim 1, wherein the area designating means automatically designates the area according to an image quality mode such as a photograph or a character in the content of the color image data. 3. The color management device according to claim 1, wherein the area designation means automatically designates the area according to the color or hue of each pixel of the color image data. 4. A color management device intended to make color image data output from an image output device the same color as color image data input from an image input device, wherein a plurality of color image data are converted from input color image data to output color image data. Color reproduction area conversion means; means for obtaining a histogram for the color of the input color image data; means for specifying the color reproduction area conversion means with respect to the frequency of the histogram; and color reproduction area conversion corresponding to the frequency for each color. And a means for switching to image data conversion of the means. 5. A color management device intended to make color image data output from an image output device the same color as color image data input from an image input device, wherein a plurality of color image data from input color image data to output color image data are provided. Color reproduction area conversion means; means for converting the plurality of color reproduction area conversion means and automatically outputting in order; means for selecting the output color image data; A color management device comprising means for switching to image data conversion of the selected color reproduction area conversion means.