JP2002077659A - Method and apparatus to attain favorite color conversion - Google Patents

Method and apparatus to attain favorite color conversion

Info

Publication number
JP2002077659A
JP2002077659A JP2000268019A JP2000268019A JP2002077659A JP 2002077659 A JP2002077659 A JP 2002077659A JP 2000268019 A JP2000268019 A JP 2000268019A JP 2000268019 A JP2000268019 A JP 2000268019A JP 2002077659 A JP2002077659 A JP 2002077659A
Authority
JP
Japan
Prior art keywords
color conversion
color
image
data
method according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2000268019A
Other languages
Japanese (ja)
Inventor
Hirotetsu Ko
博哲 洪
Original Assignee
Konica Corp
コニカ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Konica Corp, コニカ株式会社 filed Critical Konica Corp
Priority to JP2000268019A priority Critical patent/JP2002077659A/en
Publication of JP2002077659A publication Critical patent/JP2002077659A/en
Application status is Pending legal-status Critical

Links

Abstract

(57) Abstract: The present invention relates to a method for realizing a favorite color conversion and an apparatus for realizing a favorite color conversion. First, a method for converting to a favorite color can be efficiently obtained. It is another object of the present invention to provide a method for realizing desired color conversion and an apparatus for realizing desired color conversion that can be converted at high speed by actual color conversion means. SOLUTION: The color conversion applied to the sample image is created as a multidimensional color conversion table, and the data is incorporated into the color conversion means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for implementing desired color conversion and an apparatus for implementing desired color conversion.

[0002]

2. Description of the Related Art As a color management method, a color reproduction method based on device-independent colors has been proposed. here,
The color management method is a method in which anyone can obtain a color image of a certain quality as long as a predetermined procedure is performed. According to this color management method, a subject (or a target color) is temporarily changed to a value based on a colorimetric value, and the value is converted into an appropriate color signal to an output device and output.

[0003] According to this technique, a subject (or a target color) and an output result are apparently approximated colors based on an objective criterion such as a color difference. This method is widely used as a color management system that can be used by everyone, since the adjustment can be performed objectively with a colorimeter. For a description of this color management system, see the description of the journal of the Institute of Information and Media Engineers, “Hirohiro Ko, Trends in Color Management, Journal of the Institute of Image Information and Television Engineers, pp.
(1998) ".

In Japanese Patent Application Laid-Open No. 2000-32281, in order to correct a calculation error in a conventional color management system, the color of an image read by an input device and the color of an output image on a display device match. Convert the color to
There is disclosed a technique for determining and correcting a table so that the colors of a document match.

However, this method does not aim at obtaining a desired color reproduction. For this reason, it is premised that fine correction is performed when a target color exists, and no method of selecting a sample image or solving a problem with skipping of gradation is disclosed. Furthermore, since the correction is not performed in the color space based on the display device, there is a problem that the number of steps is increased.

[0006] Photo retouching software is known as a means for changing the color of an image. This is to change the gradation, hue, saturation, and brightness of an image as a whole or for each color region.

[0007]

However, a general user seeks color reproduction that matches his / her favorite color, rather than perfect color matching with the subject. To achieve this, an acceptable color is used by utilizing the degree of freedom of color gamut mapping, which is one stage of processing performed by the color management system. However, since it is not a direct method, it has been difficult to obtain good results when applying this to general images. As a result, the user could not obtain a desired color while taking a lot of time for trial and error.

The present invention has been made in view of such a problem, and firstly, a method for converting to a desired color can be efficiently obtained, and secondly, conversion can be performed at high speed by actual color conversion means. It is an object of the present invention to provide a method for realizing desired color conversion and an apparatus for realizing desired color conversion.

[0009]

(1) The invention according to claim 1 is characterized in that a color conversion applied to a sample image is created as a multidimensional color conversion table, and the data is incorporated in the color conversion means. .

With such a configuration, by using the color conversion table of the color conversion process performed on the sample image,
An input image can be converted to a desired color. (2) The invention according to claim 2, wherein the color conversion table comprises:
It is characterized in that it is combined with another color conversion table based on a color space based on the display device and incorporated in the color conversion means.

According to this structure, the desired color conversion can be performed by combining the color conversion table and the color conversion table based on the display device. (3) The invention described in claim 3 is characterized in that the data stored in the conversion table is subjected to a smoothing process.

With this configuration, the color conversion table data is subjected to a smoothing process, so that the desired color conversion characteristics can be made smooth and color skipping can be prevented. (4) According to the invention described in claim 4, the part of the image to be converted is 3
It is characterized by including patch data for creating a dimensional LUT.

With this configuration, the LU for image conversion is used.
T can be easily created. (5) The invention according to claim 5 is characterized in that the applied color conversion data is stored and a color conversion table is created in accordance with the stored data.

With this configuration, the color conversion data can be used as a color conversion table. (6) The invention according to claim 6 is characterized in that the subject is mainly a portrait.

With this configuration, since the subject is limited to a human image, the tendency of preference is similar, which is preferable. (7) The invention according to claim 7 is characterized in that the color conversion is a color conversion of a film scanner.

With this configuration, when there is no target color in a negative film or the like, the color expected by the user can be set as the final target, and optimal color conversion as a film scanner can be performed. it can.

(8) An image color processing means for inputting a representative image from an image input device and performing color processing while viewing a display device by photo retouching software, and the image color processing means 3D LUT created by
A color conversion processing unit that performs a desired color conversion process on image input data using the output of the three-dimensional LUT, and an output color conversion processing unit that receives an output of the color conversion processing unit. It is characterized by the following.

With this configuration, by using the color conversion table of the color conversion process performed on the sample image,
An input image can be converted to a desired color.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.

Although the main subject of the apparatus shown in FIG. 1 is not limited, it is preferable that the subject is relatively limited, such as an ID photographer for photographing a face. ITU-BT 709
An image taken by a television camera adjusted according to the standard or the like has almost the same color as the subject when viewed on a display.

However, the user is not satisfied with this color. The reason is that the user has a favorite color reproduction or memory color. For example, Japanese prefer a slightly pinkish color for their skin color, and a deep blue for the blue sky.

In FIG. 1, reference numeral 1 denotes an image to which a representative image output from an image input device (for example, a television camera or a scanner) is input and converted into a desired color while viewing an image displayed on a display device 2. The color processing means 2 is a display device for displaying the input image data as described above.

Reference numeral 3 denotes a three-dimensional LUT created from color characteristic data obtained when the image color processing means 1 is operated.
Reference numeral 4 denotes a favorite color conversion processing unit for converting an input image into a desired color based on the color conversion characteristics of the three-dimensional LUT 3, reference numeral 5 denotes an image storage device for storing an output of the favorite color conversion processing unit 4, and reference numeral 6 denotes an input. An output color conversion processing unit attached to the image output device when outputting an image. The operation of the device configured as described above will be described below.

First, the operator selects a representative image in order to make the color his favorite color. At this time, it is preferable that not only one representative image but also a plurality of, for example, about four, representative images can be simultaneously viewed. In this case, 3
At the same time, color chart data necessary for creating a dimensional LUT is inserted.

FIG. 2 is a diagram showing an example of a representative image. a is an image area, and b is an LUT storage area (color chart data). Thus, the LUT storage area is provided in a part of the image. The initial value of this LUT may be determined in advance to have an average characteristic. Although this method can be performed most efficiently, the conversion procedure may be stored and applied separately to the color chart data.

As an example of the color chart data, 33 × 33 × 3
3, the RGB = (0,0,0), (8,0,
0), ... (248, 0, 0), (255, 0, 0),
(0,8,0), (8,8,0), ..., (255,25
5,255) (data when input and output match). That is, in this case, data of 35937 pixels is required, but even if attached to the end of the image,
It occupies only an area of about 512 × 71.

Based on this image, the operator sets the hue (may be local), gradation curve, saturation, lightness, etc. so that the desired color can be obtained. Adjust with. A typical example of such software is Pho from Adobe.
There is a “toshop”, but it may be something else.

At this time, the image display device 2 is a standard CRT display, preferably sRGB (IEC 61966 2.1 "Color" including observation conditions.
Measurement and Multimed
ia Systems and Equipment,
Part 2.1: Default RGB Colo
r Space: sRGB ”(1999) is desirable.

When the operator operates the image color processing means 1 to perform color adjustment, the color value of the color chart in the LUT storage area b changes simultaneously with the adjustment for the image. Therefore,
3D LUT3 by storing the value of the LUT storage area of b
LUT for image conversion can be easily created.

The favorite color conversion processing unit 4 performs color conversion on the input image data using the three-dimensional LUT 3. According to this, a color conversion that gives a color that is approximately desired is realized.

Of course, it is inevitable that the favorite color changes for each type of image. However, if the image almost covers the image for which the type of the representative image is expected to be input, there is no major failure. Color reproduction can be performed in a desired direction.

In this way, the image data output from the favorite color conversion processing section 4 is stored in the image storage device 5. By the above-described photo retouching operation, the display device 2
Then, since the color becomes almost a favorite color, an image is reproduced by an output device (for example, a printer) by a color reproduction method of colorimetrically or apparently reproducing the color.

Specifically, the image data read from the image storage device 5 is output to the image output device via the output color conversion processing section 6. For this purpose, a method of a conventional color management system can be applied.

Thus, the created LUT can be combined with another LUT, and the color reproduction LUT required for the output device is combined, thereby completing one color reproduction process. FIG. 3 is a block diagram showing a second embodiment of the present invention. 1 are denoted by the same reference numerals. In this embodiment, the image storage device 5 is provided after the image input device. Therefore, in this case, image data that has not been subjected to color conversion is stored. The image data stored in the image storage device 5 is read out as needed and adjusted to a desired color by the image color processing means 1.
Using the created three-dimensional LUT 33, the input image data is converted into a desired color by the favorite color conversion processing unit 4.
The converted image data is output by the image output device via the output color conversion processing unit 6.

FIG. 4 is a block diagram showing a third embodiment of the present invention. 1 are denoted by the same reference numerals. In the figure, reference numeral 10 denotes a first color conversion processing unit that receives image data from the image input device and performs color conversion.
Reference numeral 1 denotes an image color processing unit that receives an output of the first color conversion processing unit 10 and adjusts an image, and 2 denotes an image display device that displays image data.

Reference numeral 3 denotes a three-dimensional LUT created by image adjustment by the image color processing means 1, and reference numeral 4 denotes a favorite color conversion processing unit for converting an input image into a desired color by the three-dimensional LUT 3. The output of the favorite color conversion processing section 4 also enters the image display device 2 and is displayed. In this embodiment,
For example, the present invention is suitably applied to a film scanner, particularly a scanner for a negative film. The operation of the device configured as described above will be described below.

The first color conversion processing section 10 receives image data and performs color conversion with relatively low contrast so that each color is not saturated. The operator receives the output of the first color conversion processing unit 10 and
Color adjustment while watching the screen. In this case, the contrast in the necessary portion of the input image data is increased,
Unnecessary portions are subjected to processing such as saturation.

The goals of the first color conversion processing unit 10 are as follows.
The color of the subject may be adjusted. This configuration is effective for negative film scanners. The reason is that there is no target color, and the color (memory color, expected color) expected by the user is the final target.

In the case of this configuration, as in the embodiment shown in FIG. 1, a representative image is scanned and the desired color is set to the desired color by the image color processing means 1, and the characteristic is set as a three-dimensional LUT 3. Incorporate. The output of the first color conversion processing unit 10 is converted into a desired color by the favorite color conversion processing unit 4 and displayed on the image display device 2. Finally, the first color conversion processing unit 10 and the current color reproduction LUT are combined into one color reproduction LUT, and thereafter, can be used as a scanner system for reproducing a desired color. .

If a plurality of sets of the LUTs are prepared and switched according to the type of the subject or the film,
More preferable images can be obtained for each type of subject and film.

By applying the following smoothing to the created LUT, for example, the desired color conversion characteristics are smoothed, and it is possible to make the LUT hard to break down to other images.

[0042]

(Equation 1)

This equation indicates a smoothing process in a three-dimensional space, and if one-dimensionally described, it is as shown in FIG. P0 to P4 are one-dimensional pixel values.
Here, when the above equation is applied to the point of P1, the smoothed value P1 ′ of P1 is as follows. P1 '= (P
0 + P1 + P2) / 3 (2) As described above, when the smoothing process is performed based on the values before and after the target pixel, the characteristic shown by the solid line in the drawing is converted into the characteristic shown by the broken line, and the smoothed one is obtained. When an LUT having such characteristics is used, the color conversion characteristics become smooth, and color skipping hardly occurs.

In the above-described embodiment, the case where the color chart data is inserted into the image has been described. However, the present invention is not limited to this, and separates image and color chart data,
It is also possible to store the color conversion processing for the image and apply it to the color chart data.

Further, the color chart data does not need to have all the grid points required for the color conversion LUT. For example, every other data may have data, and missing portions may be interpolated. It is also preferable to apply the present invention to one negative having different characteristics. Especially when scanning old negatives, etc.
Since the color balance and the color tone are shifted as a whole, they can be used as a means for correcting them.

The system of the present invention is particularly suitable for an ID photographing system. The reason is that, since the subject is limited to a human image, the tendency of “favorite color” is similar. It is preferable that the photo retouching software has a function to warn when a gradation jump occurs. Further, the three-dimensional LUT conversion can be performed on the photo retouching device side. Similarly, smoothing
This can be done with photo retouching software.

The effects of the present invention are listed below. By using various procedures performed on an image as a multidimensional color conversion table, color conversion of another image can be performed at high speed.

The printing of the screen is realized by a conventional color management system, and as long as the desired color is displayed on the screen, the print can be almost made a first impression. In addition, since the two transforms are combined into one, the operation speeds up.

In the color conversion using the photo retouching software, the gradation tends to jump, but the smoothing results in a smooth gradation, and the breakdown occurs even when different types of images are input. Hateful.

By including the patch data for creating the three-dimensional LUT in a part of the image, the LUT data can be adjusted simultaneously with the adjustment performed on the image, and the procedure can be simplified.

The image and the color chart data can be handled independently, and no unsightly color chart data appears when the image is small. Since the subject is mainly a portrait, it is unlikely to break down.

In particular, when the color required by the user is unknown for a negative film or the like, a film scanner that reproduces a desired color with a minimum of trial and error can be manufactured.

[0053]

According to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, the input image can be converted into a desired color by using the color conversion table of the color conversion processing performed on the sample image.

(2) According to the second aspect of the present invention, the desired color conversion can be performed by combining the table and the color conversion table based on the display device. (3) According to the third aspect of the present invention, smoothing processing is performed on the color conversion table data, so that the desired color conversion characteristics can be smoothed and color skipping can be prevented.

(4) According to the fourth aspect of the invention, an LUT for image conversion can be easily created. (5) According to the fifth aspect of the invention, the color conversion data can be used as a color conversion table.

(6) According to the sixth aspect of the present invention, since the subject is limited to a person image, the tendency of preference is similar, which is preferable. (7) According to the seventh aspect of the invention, when there is no target color in a negative film or the like, the color expected by the user can be set as the final target, and the optimum color conversion as a film scanner can be achieved. Can do it.

(8) According to the eighth aspect of the present invention, the input image can be converted into a desired color by using the color conversion table of the color conversion processing applied to the sample image. As described above, according to the present invention, first, a method of converting to a desired color can be efficiently obtained, and second, a desired color that can be converted at high speed by actual color conversion means. It is possible to provide a method for realizing the conversion and an apparatus for realizing the desired color conversion.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a representative image.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a smoothing process.

[Explanation of symbols]

 Reference Signs List 1 image color processing means 2 display device 3 three-dimensional LUT 4 favorite color conversion unit 5 image storage device 6 output color conversion processing unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B057 AA11 BA11 CA01 CA12 CB01 CB12 CE05 CE17 CE18 CH07 5C066 AA01 BA01 BA13 CA05 GA01 HA03 HA06 KE01 KE16 KM01 KM11 KM17 5C077 LL05 LL18 LL19 MM27 MP08 PP02 SS31P09 SS01 5C079 HB01 HB06 HB11 LA00 LB02 LB11 MA02 MA04 MA20 NA03 NA11 NA13 PA05 PA08

Claims (8)

[Claims]
1. A method for implementing a desired color conversion, wherein a color conversion applied to a sample image is created as a multidimensional color conversion table, and the data is incorporated into a color conversion means.
2. Combining the color conversion table with another color conversion table based on a color space based on a display device,
2. The method according to claim 1, wherein the method is implemented in a color conversion unit.
3. The method according to claim 1, wherein a smoothing process is performed on the data stored in the color conversion table.
4. The method according to claim 1, wherein a part of the image to be converted includes patch data for creating a three-dimensional LUT.
5. The method according to claim 4, wherein said applied color conversion data is stored, and a color conversion table is created according to said stored data.
6. The method according to claim 1, wherein the subject is mainly a portrait.
7. The method according to claim 1, wherein the color conversion is a color conversion of a film scanner.
8. An image color processing means for inputting a representative image from an image input device and performing color processing while looking at a display device with photo retouching software, a three-dimensional LUT created by the image color processing means, A color conversion processing unit that performs a desired color conversion process on image input data using the output of the three-dimensional LUT, and a color conversion processing unit for output that receives the output of the color conversion processing unit. A device that realizes color conversion.
JP2000268019A 2000-09-05 2000-09-05 Method and apparatus to attain favorite color conversion Pending JP2002077659A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000268019A JP2002077659A (en) 2000-09-05 2000-09-05 Method and apparatus to attain favorite color conversion

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000268019A JP2002077659A (en) 2000-09-05 2000-09-05 Method and apparatus to attain favorite color conversion

Publications (1)

Publication Number Publication Date
JP2002077659A true JP2002077659A (en) 2002-03-15

Family

ID=18754846

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2000268019A Pending JP2002077659A (en) 2000-09-05 2000-09-05 Method and apparatus to attain favorite color conversion

Country Status (1)

Country Link
JP (1) JP2002077659A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003001791A1 (en) * 2001-06-26 2003-01-03 Seiko Epson Corporation Image-processing device and method, program, and recording medium
US7853078B2 (en) 2006-05-10 2010-12-14 Sony Corporation Setup-screen display controlling apparatus, server apparatus, image processing system, printing apparatus, image pickup apparatus, display apparatus, setup-screen display controlling method, program, and data structure
US8014598B2 (en) 2006-07-18 2011-09-06 Samsung Electronics Co., Ltd. Method and apparatus for changing a pixel color
US8503775B2 (en) 2007-06-29 2013-08-06 Canon Kabushiki Kaisha Image processing method and image processing apparatus
US8624824B2 (en) 2009-03-19 2014-01-07 Sharp Laboratories Of America, Inc. Area adaptive backlight with reduced color crosstalk
JP2015525037A (en) * 2012-07-27 2015-08-27 イーストマン コダック カンパニー Method for reducing metamerism mismatch between observers

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003001791A1 (en) * 2001-06-26 2003-01-03 Seiko Epson Corporation Image-processing device and method, program, and recording medium
US7777914B2 (en) 2001-06-26 2010-08-17 Seiko Epson Corporation Image-processing device and method using combined color correction table
US7853078B2 (en) 2006-05-10 2010-12-14 Sony Corporation Setup-screen display controlling apparatus, server apparatus, image processing system, printing apparatus, image pickup apparatus, display apparatus, setup-screen display controlling method, program, and data structure
US8014598B2 (en) 2006-07-18 2011-09-06 Samsung Electronics Co., Ltd. Method and apparatus for changing a pixel color
US8503775B2 (en) 2007-06-29 2013-08-06 Canon Kabushiki Kaisha Image processing method and image processing apparatus
US8624824B2 (en) 2009-03-19 2014-01-07 Sharp Laboratories Of America, Inc. Area adaptive backlight with reduced color crosstalk
JP2015525037A (en) * 2012-07-27 2015-08-27 イーストマン コダック カンパニー Method for reducing metamerism mismatch between observers

Similar Documents

Publication Publication Date Title
CA2043180C (en) Color correction system employing reference pictures
DE60222486T2 (en) Image processing for digital cinema
US7796296B2 (en) Personalized color reproduction
US7406213B2 (en) Image processing apparatus and method, and computer program
US5565931A (en) Method and apparatus for applying gamma predistortion to a color image signal
US5363209A (en) Image-dependent sharpness enhancement
US6975437B2 (en) Method, apparatus and recording medium for color correction
US7358988B1 (en) Image signal processor for performing image processing appropriate for an output device and method therefor
US6271940B1 (en) Color negative scanning and transforming into colors of original scene
JP3907783B2 (en) Color conversion method
US5450217A (en) Image-dependent color saturation correction in a natural scene pictorial image
US8358355B2 (en) Digital still camera and image correction method
US7327875B2 (en) Method and apparatus for color conversion
US7024035B1 (en) Method of setting region to be subjected to red eye correction and red eye correcting method
US6243133B1 (en) Method for automatic scene balance of digital images
US7636473B2 (en) Image color adjustment
US6204940B1 (en) Digital processing of scanned negative films
US5793884A (en) Spectral based color image editing
US6342951B1 (en) Gamut mapping algorithm using inverted gamma function
KR100881028B1 (en) Apparatus and method for calibration of gray data
JP3866304B2 (en) Reproduction method of natural scenery image
JP4471056B2 (en) Color image processor and image rendering method
US6744920B1 (en) Method, apparatus, and recording medium for processing image data to obtain color-balance adjusted image data based on white-balance adjusted image data
US7046400B2 (en) Adjusting the color, brightness, and tone scale of rendered digital images
US5347374A (en) Cascaded image processing using histogram prediction

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20050303

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20070628

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20070710

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20070907

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20080129