JP2003046796A - Color characteristic profile modifying system for image output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily modify a device profile, to determine modifying conditions on the basis of measured amount obtained from a colorimetric device or from amount of sense by visual observation, and to totally or partly modify a color conversion table of the device profile. SOLUTION: A first image output object Ga according to electronic image data is outputted by a first image output means Da. The data Gd is color-converted using a device profile Pa describing the color characteristics of the means Da and a device profile Pb describing the color characteristics of a second image output means Db, and electronic image data gd' is formed. The data gd' is inputted into the means Db to output an output object Gb, and the first output object is compared with the second object. The profile Pa, in which the color characteristics of the means Da are described, is modified by a modifying amount obtained by numerically replacing the modification amount on the basis of a colorimetric value (Lab value), or the amount of sense by visual observation of the same point as the point of the second output object to be modified, so that the color of the second object is made to be close to the color of the first object and as the point of the first object to be modified.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera, a video camera, a desktop personal computer, a notebook personal computer, and other two or more computers connected to a computer. The present invention relates to a color characteristic profile correction system of an image output device for realizing color transfer between devices, that is, color management. 2. Description of the Related Art For example, when a monitor profile indicating the color characteristics of a color image output monitor screen of a computer such as a personal computer is created, a color image displayed on the monitor screen is directly measured using a colorimeter. By coloring, a device profile of a color image output monitor whose profile is unknown is created. [0003] The color characteristics of an image output means such as a color printer connected to a computer such as a personal computer are based on the print output (output sheet) output from the image output means.
For example, an image of an image output product is directly measured using a colorimeter to create a device profile of the image output unit. [0004] Here, the device profile is a file in which the color characteristics of each device are described, and is internally used to perform "device signal value → PCS value" conversion and "PCS value → device signal value" conversion. Equipped with color conversion information. (PCS value: a color value in a device-independent color space, such as an XYZ value, a Lab value, etc.) This color conversion information portion is composed of two primary curves and a color conversion table. FIG. 5 shows a flowchart of the “device signal value → PCS value” conversion. In addition,
The “PCS value → device signal value” conversion is a flow chart in the reverse direction. When a color characteristic profile (device profile) of an image display device such as the image output monitor (screen) or the image output means is created, a color image using a color chart is used. A plurality of block-like color patches having different values are regularly arranged, and it is necessary to sequentially measure and record a plurality of color patches using a colorimeter. It takes a considerable amount of time to measure the color per hit, and partial correction is difficult. Further, in the conventional device profile correction system, since specialized knowledge and experience are required, it is difficult to create a desired profile. SUMMARY OF THE INVENTION An object of the present invention is to make it possible to easily correct a device profile, and to modify the correction conditions by using a measured quantity obtained from a colorimeter or a visual sensation quantity. And the color conversion table of the device profile can be wholly or partially modified. According to a first aspect of the present invention, there is provided: (1) a first image output means Da for outputting a first image output object Ga based on electronic image data gd. And (2) a device profile Pa of the first image output means Da represented by C, M, Y, K values and Lab values.
And using the device profile Pb of the second image output means Db represented by C, M, Y, K values and Lab values, to convert the color of the electronic image data gd. Outputting a second image output object Gb;
(3) It is desired to visually compare the colors of the first image output product Ga and the second image output product Gb and correct the second image output product Gb so that the color approaches the first image output product Ga. La and the same portion of the first image output product Ga that is desired to be corrected in the second image output product Gb
b The colorimetric value Ta at each location is measured by the colorimetric means.
(Lab value) and a colorimetric value Tb (Lab value).
(4) calculating a color correction amount based on the colorimetric values Ta and Tb at the respective locations, and rewriting and correcting all or a part of the color conversion table of the device profile Pa of the first image output means Da; And a color characteristic profile correction system for an image output device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color characteristic profile correcting system for an image output device according to the present invention will be described in detail below. FIG. 1 is a system flow chart for explaining the stage of outputting the first image output product Ga in the system of the present invention. The predetermined electronic image data gd shown in FIG.
Is prepared, and the data gd is input to the first image output means Da shown in FIG. The device profile Pa of the first image output means Da describes the color characteristics of the image output means Da, and has a C value (cyan density% value) and an M value (magenta density%). Value), Y value (density% of yellow color)
Value), K value (density value of black color), and Lab value (color value). The electronic image data gd is
The data may be data recorded on a predetermined recording medium or data read in real time. FIG. 1 shows a first image output means Da.
The first image output Ga shown in (c) is output. This image output product Ga is a target in color matching. FIG. 2 is a system flow chart for explaining the stage of outputting the second image output object Gb. As shown in FIG. 2A, the predetermined electronic image data shown in FIG. The same electronic image data as that of gd is prepared, and color conversion is performed using the device profile Pa of the first image output unit Da and the device profile Pb of the second image output unit Db to create electronic image data gd ′. The data gd 'is input to the second image output means Db shown in FIG. The device profile Pb of the second image output means Db describes the color characteristics of the image output means Db, and includes a C value (cyan density% value) and an M value (magenta density%). Value), Y value (density% of yellow color)
Value), K value (% density value of black color), and Lab value. Here, as shown in FIG. 2A, according to the device profile Pb provided in the second image output means Db, the CMYK values of the image data are converted into PCS values (values in a device-independent color space, Lab , XYZ values), and converts this PCS value into a C′M′Y′K ′ value according to the device profile Pb of the second image output means Db. Output means Da
The electronic image data gd ′ for outputting the second image output product Gb reflecting the color characteristics of the above is created. The electronic image data g subjected to the color conversion E
d ′ is converted to the second image output means D as shown in FIG.
b from the second image output means Db.
The second image output object Gb shown in (c) is output. Next, as shown in FIG. 3A, when the colors of both the first image output product Ga and the second image output product Gb are compared, the first image output product Gb has the first image output product Gb. A colorimetric measurement is performed by a Lab colorimeter on a portion to be corrected so as to bring the color closer to the image output material Ga, and a portion of the first image output material Ga which is the same as the portion to be corrected of the second image output material Gb. Then, a colorimetric value Ta (Lab value) and a colorimetric value Tb (Lab value) are obtained for each location, and then, as shown in FIG. 3B, a correction amount is calculated, and the colorimetric values Ta and A difference value of Tb is obtained, and this is set as a correction amount. As another embodiment, FIG.
As shown in (a), when the colors of the first image output product Ga and the second image output product Gb are visually compared, the second image output product Gb approaches the first image output product Ga. The color, the direction of lightness, and the strength to be corrected are sensibly determined, and these sensory quantities Sa and Sb are respectively set to appropriate La.
As shown in FIG. 4C, the sensory amount S is replaced with the b value.
The difference value between a and Sb (similarly, the amount of sensation) is determined as the correction amount. Next, as shown in FIGS. 3 (c) and 4 (c), respectively, the correction amount by calculation as the difference value between the colorimetric values Ta and Tb or the correction amount by the above sensation is given by the first
In addition to the Lab value of the color conversion table of the device profile Pa of the image output means Da, a part or all of the color conversion table of the device profile Pa is corrected to create a corrected device profile Pa ′. When correcting all, the La of all grid points in the color conversion table of the device profile Pa
When the above difference value is added to the b value and part of the value is changed, the Lab value of the grid point within a certain color difference from the colorimetric value Ta is used.
The above difference value is added only to the value. According to the system of the present invention, the colorimetric values (La) of the first image output material and the second image output material by the colorimetric means are provided.
The device profile is corrected by the correction amount based on the b value), or the amount of visual sensation is changed to an appropriate value (L
(ab value), the sensory amount is reflected in the correction, and the correction amount is determined from the sensory amount to correct the device profile, so that the device profile can be easily corrected and the profile quality improved. In addition, unlike the conventional device profile creation system, the device profile can be corrected not only entirely but also partially, which is effective in reducing the load of the correction work. . In the system of the present invention, when changing or correcting a part or all of a device profile describing a device-specific color characteristic provided in advance in an image display device, one or more device profiles unique to each device are provided. Can be changed and corrected to a predetermined device profile in a short time, and there is an effect that a change and correction of a color characteristic profile including color matching in color display between devices can be realized at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) to 1 (c) show a system according to the present invention.
FIG. 4 is a flowchart illustrating a process of outputting a first image output using a first image output unit based on electronic image data. FIGS. 2 (a) to 2 (c) show the system of the present invention.
FIG. 4 is a flowchart illustrating a process of outputting a second image output using a second image output unit based on electronic image data. FIGS. 3 (a) to 3 (c) show the system of the present invention.
Colorimetric values (colorimetric La) at the same location on the first and second image output
FIG. 9 is a flowchart illustrating a process of correcting a device profile based on (b value). FIGS. 4 (a) to (c) illustrate the system of the present invention.
The amount of sensation at the same location of the first and second image output products (sensory L
FIG. 9 is a flowchart illustrating a process of correcting a device profile based on (ab value). FIG. 5 is a flowchart illustrating a general device profile having color conversion information and a color conversion process. [Description of Signs] gd: electronic image data gd ′: electronic image data after color conversion Da: first image output unit Db: second image output unit Ga: first image output product Gb: second image Output product Pa: first device profile Pa ': first device profile Pb after modification ... second device profile Ta: colorimetric value of first image output product Tb: colorimetry of second image output product value

Continuation of front page    F term (reference) 2C262 AB11 AB17 BA01 BA15 BA17                       BA18 BC19 CA07 EA04 EA12                       EA13                 5B057 AA11 CA01 CA08 CA12 CA16                       CB01 CB08 CB12 CB16 CC01                       CE17 CE18 CH07 CH08                 5C066 AA05 CA08 CA17 EE02 GA01                       GA02 GA05 KE09                 5C077 LL19 MP08 PP33 PP36 PP37                       PP47 PQ12 PQ20 PQ23 SS02                       SS06 TT02 TT09                 5C079 HB03 HB08 LB02 MA05 MA11                       MA17 NA03 PA03 PA05

Claims (1)

Claims: 1. A first method based on electronic image data gd.
And (2) the device profile P of the first image output means Da represented by C, M, Y, K values and Lab values.
a and the device profile Pb of the second image output means Db expressed by C, M, Y, K values and Lab values,
Color-converting the electronic image data gd and outputting a second image output Gb by a second image output means Db;
(3) It is desired to visually compare the colors of the first image output product Ga and the second image output product Gb and correct the second image output product Gb so that the color approaches the first image output product Ga. La and a place in the first image output product Ga that are the same as a place where the second image output product Gb is to be corrected
b The colorimetric value Ta at each location is measured by the colorimetric means.
(Lab value) and a colorimetric value Tb (Lab value).
(4) calculating a color correction amount based on the colorimetric values Ta and Tb at the respective locations, and rewriting and correcting all or a part of the color conversion table of the device profile Pa of the first image output means Da; A color characteristic profile correction system for an image output device, comprising: