KR20000019374A - Measuring instrument for measuring color reproduction region of color device and method for extracting limiting region for color reproduction - Google Patents

Abstract

PURPOSE: A measuring instrument and a method are provided to disposal a color which gives rise to a problem by finding a color region which color device is able to reproduce visually in advance. CONSTITUTION: A measuring instrument comprises an extracting unit(100) for extracting the color reproduction characteristic information of color device, an extracting unit(200) for extracting the color reproduction limiting region information of color device and a color reproduction region expression unit(300). The extracting unit for extracting the color reproduction characteristic information of color device calculates a reference white coordinate of color device, calculates a triple extreme value and a color coordinate on basis of the reference white coordinate and a triple extreme value and a color coordinate of a unique fundamental color of color device, and extracts a color reproduction sensitivity coefficient of each nozzle and color gun and convert it to color coordinate independence on the device. The extracting unit for extracting the color reproduction limiting region information of color device extracts maximum and minimum luminosity value which the device reproduces from the information of the first extracting unit, calculates a spherical coordinate, chroma and brightness according to user, and comprises a color reproduction width matrices and control its continuity. The color reproduction region expression unit after give discrimination information by converter spherical coordinate date to rectangular coordinates data by using the color reproduction width matrices, selects a color space coordinate which the user wants, visualizes the color reproduction width, and compares the color reproduction width information each other and stores them.

Description

Color Device Color Reproduction Area Meter and Color Reproduction Limit Area Extraction Method

The present invention relates to a color device color reproduction area measuring instrument and a color reproduction limit area extraction method. In particular, the color reproduction area of a color device is expressed in a three-dimensional space in accordance with a user's request by using device color reproduction characteristic information. Based on this, the present invention relates to a color device color reproduction area measuring instrument and a color reproduction limit area extraction method for detecting a color that cannot be reproduced in advance in a color input device and an output device.

In recent years, as the demand for color reproduction, color scanners, monitors, and printers is increasing, the importance of utilization of the color reproduction field is increasing day by day. Especially in advanced foreign countries, the utilization of color equipment manufacturers is high, which is fostering as a national strategic industry.

A common conventional method has been to find a color that cannot be reproduced by an expert's many years of experience. Such a conventional method is not only accurate but also causes waste of unnecessary resources such as excessive use of print paper, and is difficult to transfer by an experience-based method, and takes a long processing time through trial and error every time.

Therefore, in the present invention, in order to solve the above-mentioned disadvantages, the color device color reproduction area measuring instrument and color reproduction, which enables the user to grasp the color gamut that the color device can reproduce in advance, and to process the color in question. The purpose is to provide a method for extracting marginal areas.

The color device color reproduction area measuring instrument according to the present invention for achieving the above object calculates the reference white coordinate of the color device, and based on the reference white coordinate of the color device, tristimulus values and color coordinates, and the primary color unique to the color device. A color device color reproduction characteristic information extracting means for calculating tristimulus values and color coordinates of the color sensor, extracting the color reproduction sensitivity coefficients of each nozzle and color gun, and converting them into device independent color coordinates; and the color device color reproduction characteristic information extracting means. Using the received color reproduction characteristic information, the device extracts the maximum minimum luminance value that can be reproduced by the device, calculates spherical coordinates, saturation values, and brightness values according to a user's selection, constructs a color reproduction width matrix, and adjusts the continuity thereof. Color device color reproduction marginal area information extraction means and the color reproduction width metric After converting the spherical coordinates into rectangular coordinate data to give identification information, select the color space coordinates that the user wants to see, visualize the color reproduction width in three dimensions from the selected color space coordinates, and reproduce the previously stored color. And color representation area representation means for comparing and analyzing the width information with the color reproduction width information of another device.

In addition, the method for extracting the color device color reproduction limit region according to the present invention for achieving the above object comprises the steps of extracting the color device color reproduction region characteristic information to extract information for constructing the limit region in the color device; Extracting the information of the color reproduction limit region using the sensitivity of the device color reproduction region characteristic information; and configuring the extracted color reproduction limit region in three dimensions and using the information selected by the user in three spaces. And expressing a possible color reproduction area.

1 is a block diagram of a color device color reproduction area measuring instrument according to the present invention.

2 is a flow chart of color device color reproduction characteristic information extraction according to the present invention;

3 is a flowchart of extracting color reproduction limit region information according to the present invention;

4 is a conceptual diagram of color reproduction data configuration according to the present invention;

5 is a flowchart of a color reproduction area representation according to the present invention;

<Description of the reference numerals for the main parts of the drawings>

100: color device color reproduction characteristic information extraction means

200: means for extracting color gamut information

300: means for representing color reproduction area

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 is a configuration diagram of a color device color reproduction area measuring instrument according to the present invention, which includes a color device color reproduction characteristic information extracting means 100, a color reproduction limit region information extracting means 200, and a color reproduction region expressing means 300. It is composed.

The color device color reproduction characteristic information extracting means 100 calculates tristimulus values (X, Y, Z) and L ^* , a ^* , b ^* color coordinates based on x, y, Y of the intrinsic white coordinates of the corresponding color device. Calculate In addition, the tristimulus values (X, Y, Z) and L ^* , a ^* , b ^* coordinates of the color device intrinsic primary colors (red, green, blue, cyan, magenta, and sulfur) are calculated, and the color of each nozzle and color gun is calculated. The reproduction sensitivity coefficient is extracted and converted into device independent color coordinates (CIE XYZ space).

The color reproduction limit region information extracting means 200 extracts a unique maximum minimum luminance value that can be reproduced by the device using the color reproduction characteristic information received from the color device color reproduction characteristic information extracting means 100. In addition, Spherical Coorinates, Chroma and Lightness are calculated, color reproduction width matrix is constructed, and continuity between variables is adjusted to be the basic data structure of color operation system other than the present invention. It can also be used.

In the color reproduction area representation means 300, the information obtained by the color reproduction limit region information extraction means 200 is converted into rectangular coordinate data using the color reproduction width matrix, and the color, thickness, etc. of a line representing three-dimensional coordinates are expressed. After assigning the identification information, it converts to CIE XYZ space, CIE L ^* a ^* b ^* space, LCH space, visualizes the color reproduction width in three dimensions, and compares and analyzes the information with other devices according to the user's request. .

2 is a flowchart illustrating color device color reproduction characteristic information extraction according to the present invention.

The color device color reproduction characteristic information extracting means 100 extracts color characteristic information of the color device. The color characteristic information is used as a parameter for deriving a color range that can be reproduced by a color device. The color characteristic information is measured in a stable environment, and can be divided into four stages.

The first is the white coordinate calculation step (S110), the second is the primary color coordinate calculation step (S120), the third is the color reproduction sensitivity coefficient extraction step (S130), and the fourth is the device independent color coordinate conversion step (S140).

The white coordinate calculation step (S110) is a step of calculating the color coordinate value to be used in the color reproduction sensitivity coefficient extraction conversion step (S130) by measuring the white color of the corresponding color device with a color measuring device such as a color limiter or a chromameter.

The primary color coordinate calculation step (S120) is performed by using color measuring equipment such as color limiters or chromameters (red, 255, 0, 0), green (0, 255, 0), blue (0, 0, 255), cyan (0, 255, 255), magenta (255, 0, 255), and yellow (255, 255, 0) are measured for each color, and the color coordinate values It is a step of calculating to be used in (S130).

The primary color color reproduction sensitivity coefficient extraction step (S130) is a step of deriving a functional relationship between a color and a mechanical voltage using the color coordinates calculated in the white coordinate calculation step S110 and the primary color coordinate calculation step S120. to be.

The device independent color coordinate conversion step S140 derives a value used in the color reproduction limit region information extracting means 200 using the following equations.

L ^* = 116 ^* (Y / Y _n ) ¹ /3-16.0 (Y / Y _n > 0.008856)

L ^* = 903.3 ^* (Y / Y _n ) ^1/3 (Y / Y _n <= 0.008856)

a ^* = 500 ^* [(X / X _n ) ¹ / ^3- (Y / Y _n ) ^1/3 ]

b ^* = 200 ^* [(Y / Y _n ) ¹ / ^3- (Z / Z _n ) ^1/3 ]

3 is a flowchart of extracting color reproduction limit region information according to the present invention.

The color reproduction limit region information extracting means 200 extracts information of the limit region that the color device can express. The marginal area information is used as basic information for deriving a color range that can be reproduced by a color device. The information is composed of 16 * 16 = 256 pieces of information and a total of 258 variables as maximum and minimum luminance values. Can be divided.

The first step is to extract the maximum and minimum luminance values (S210), the second step is to calculate the spherical coordinates (Alpha) or chroma (Chroma) according to the user's selection (S211), and the third is the spherical coordinates ( Theta) or calculating brightness values (S230 and S250), and the fourth step is configuring a color reproduction width matrix using the variables generated in the second and third steps (S260). Fifth, in step S270, the continuity is adjusted using neighboring variables with extreme variables in the color reproduction width matrix.

The maximum and minimum luminance value extraction step S210 may be used to adjust the spacing of the matrix in the color reproduction width matrix configuration step S260 by calculating the luminance value that can be reproduced at the maximum and the luminance value that is reproduced at the minimum. That's the step. After this step, a spherical coordinate system and a rectangular coordinate system are selected according to the purpose of using the color gamut mapping algorithm (S211). In the case of the spherical coordinate system, the calculation of the spherical coordinates (Alpha, Theta) (S220, S230) follows the following equation.

α = tan ^-1 (b ^* / a ^* )

θ = tan ^-1 ((L ^* -50.0) / (a ^{* 2} + b ^{* 2} ) ^1/2 )

In addition, the following numerical values are filled when the above equation is added to form a color reproduction width matrix (S260).

r = [(L ^* -50) ² + (a ^{* 2} + b ^{* 2} )] ^1/2

In the case of the rectangular coordinate system, the rectangular coordinates (Chroma, Lightness) calculation (S240, S250) is based on the following equation.

Chroma = (a ^{* 2} + b ^{* 2} ) ^1/2

Lightness = 116 ^* (Y / Y _n ) ¹ /3-16.0

In this case, the numerical value of Chroma itself is filled in the matrix when the above equation is added to form a color reproduction width matrix (S260).

The color reproduction width matrix constructing step S260 is a step of filling the matrix calculated by the steps S220 to S250 into a matrix of 16 * 16 based on a predetermined rule, which will be described later in detail with reference to FIG.

In the matrix continuity adjusting step (S270), when an error occurs in some color areas among the values calculated by the color device color reproduction characteristic information extracting means 100, an extremely larger or smaller value than a neighboring value is derived, or If there is no value due to a calculation error, it is a step of correcting the continuity by using neighboring values.

4 is a conceptual diagram of color reproduction data configuration according to the present invention.

Basically, in the color reproduction width matrix configuration S260, a conversion is performed to the color reproduction width matrix transformation S263 through the data comparison and conversion step S262 in the dependent color coordinate system S261.

The dependent color coordinate system S261 includes three values of which the color device is composed of the device dependent color system, that is, red (R), green (G), blue (B) for a display device, and cyan, for a printing device. A hexagonal coordinate system may be formed based on the maximum values of magenta and yellow. In the case of linear coordinate transformation among the properties of each color, in case of linear and saturation values and spherical coordinate transformation, alpha and theta values are calculated by the horizontal and vertical subscripts of the matrix. Continue to update the saturation and the sphere distance values (r = [(L ^* -50) ² + (a ^{* 2} + b ^{* 2} )] ^1/2 ).

In the data conversion operation S262, if a value of an existing cell is smaller than a currently calculated cell value, it is converted into a current value. In this case, the matrix is the minimum number of color reproduction widths of 256 cells in total, and this data structure can be used universally not only in the present invention but also in a color operating system.

5 is a flowchart illustrating a color reproduction region according to the present invention.

The color reproduction area representation means 300 is a means for performing an expression that is as easy, accurate, and comparable as possible to users based on the data received from the color reproduction limitation area information extraction (S200), and largely nine steps Can be divided into:

The first is the rectangular coordinate data conversion step (S310), the second is the identification information providing step (S320), the third to the sixth step is to select the target space (S330, S340, S350, S360), the seventh to suit the user's preferences Visualizing the color reproduction width in three dimensions (S370), the eighth step is to enable comparison with other devices and previously stored information (S380), and the ninth step is to store the final data (S390).

In the rectangular coordinate data conversion step (S310), when the color reproduction limit region information extraction (S200) is a spherical coordinate system, the data is converted into the rectangular coordinate system so that a graphic calculation can be performed with a small amount of calculation in a three-dimensional representation. In the identification information providing step (S320), it is a step of selecting and adjusting color, thickness of a line, window size, etc. so that a user can easily observe a color reproduction width in three dimensions. In the object space selection step (S330-S360), the user can select and observe the color space that the user wants to see in CIE XYZ, CIE L ^* a ^* b ^* , LCH space. In the color reproduction width visualization step (S370), the coordinates are displayed three-dimensionally from the selected spatial coordinates. In the color reproduction mutual comparison step (S380), the color reproduction width information previously stored and the color reproduction width information of another device may be compared with each other on different windows to determine whether the color of a specific region is output in advance. The information storage step (S390) is a step of storing the processed and visualized information as a file.

As described above, the present invention can be used as a color correction device of the output device and the input device in the pre-processing step of the color image processing, and may be used in the graphics, image processing, virtual reality, printing industry, It can be used to reproduce optimal colors in hardware development. In addition, it can be used as an application library of the Color Management System that minimizes color information inconsistency between the information provider and the end user in the high-speed information communication network.

Claims (6)

The reference white coordinate of the color device is calculated, the tristimulus value and the color coordinate and the tristimulus value and the color coordinate of the primary color of the color device are calculated based on the reference white coordinate of the color device, and the color reproduction sensitivity coefficient of each nozzle and the color gun is calculated. Color device color reproduction characteristic information extracting means for extracting and converting the device into device independent color coordinates; Using the color reproduction characteristic information received from the color device color reproduction characteristic information extraction means, the maximum minimum luminance value that can be reproduced by the device is extracted, and spherical coordinates, chroma and brightness values are calculated according to a user's selection. Color device color reproduction characteristic information extraction means for constructing a reproduction width matrix and adjusting the continuity thereof; After converting the spherical coordinates into rectangular coordinate data using the color reproduction width matrix to give identification information, the user selects the color space coordinates that the user wants to see, and visualizes the color reproduction width in three dimensions from the selected color space coordinates. And a color reproduction area representation means for comparing and analyzing previously stored color reproduction width information with color reproduction width information of another device. Extracting color device color reproduction area characteristic information to extract information for constructing a marginal area from the color device; Extracting information of a color reproduction limit region using the sensitivity of the color device color reproduction region characteristic information; Extracting a color device color reproduction limit region comprising the extracted color reproduction limit region in three dimensions and expressing a color reproduction region that can be measured using information selected by a user in three spaces Way. The method of claim 2, The color device color reproduction characteristic information extraction process may include performing a white coordinate calculation and a primary color coordinate calculation that the color device can reproduce; Extracting a color reproduction sensitivity coefficient reproduced by the color device; And converting the extracted sensitivity coefficient value into device independent color coordinates. The method of claim 2, The color reproduction limit region extraction process may include extracting luminance values which can be reproduced at maximum and minimum by the device; The user selecting a linear transformation request, Converting the selected space into a rectangular coordinate system or a rectangular coordinate system according to the user's selection; Constructing a color reproduction width matrix based on the converted spherical coordinate system and the rectangular coordinate system value; And adjusting the continuity of the configured color reproduction width matrix. The method of claim 4, wherein The color reproducing width mattress is composed of a hexahedron with a maximum output area of a color device, and from this, a matrix having 16 * 16 = 256 cells is formed by using a spherical coordinate system and chroma and brightness values. Method for extracting device color reproduction limit area. The method of claim 2, The color reproduction area representation process may include converting spherical coordinates extracted from the color reproduction limit region information extraction step into rectangular coordinates; Assigning identification information to the rectangular coordinates according to a user's request; Selecting the target color space crime table that the user wants to see; Visualizing a color reproduction width in three dimensions in the selected color space coordinates; And comparing and analyzing the color reproduction width information with the color reproduction width information of another device, and storing the color reproduction width information.