KR100288455B1 - Revising system and method of color in display for video - Google Patents

Abstract

The present invention relates to a display color correcting apparatus and method, the color measuring unit for receiving the light emitted from the display to detect the chromaticity and luminance, input according to the voltage sensor and look-up table for detecting the VGA voltage output from the video card The video display color correction device includes a color signal correction processor for outputting a VGA voltage to another correction voltage, a control unit for setting a look-up table based on a signal output from the voltage sensor and the color measurement unit, and a contrast and brightness of the display. After adjusting to maintain the independence of the three primary colors, and then detect the VGA output voltage of the three primary color signal in the predetermined brightness level of all achromatic colors with all three primary signal values constant, the luminance and chromaticity of each of red, green, and blue in the same brightness level as the achromatic color To calculate the color conversion matrix and luminance curve of the three primary colors, When the chromaticity coordinate and gamma value of white are inputted, the color difference is not generated by the video display color correction method that calculates the correction voltage of the VGA output voltage and records the VGA output voltage and the corresponding correction voltage in the lookup table. .

Description

Image display color correction device and method {REVISING SYSTEM AND METHOD OF COLOR IN DISPLAY FOR VIDEO}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color correction apparatus and method of a display device for outputting a video signal. Particularly, a predetermined color detection unit directly detects a video signal appearing on a screen to directly detect luminance and chromaticity of a color displayed on a screen, The present invention relates to a color correction apparatus and method of an image display apparatus which detects an output VGA voltage and creates a lookup table of output voltages with respect to an input voltage based on these, and corrects the colors of the displays, thereby preventing color differences for each display. .

In recent years, computer designs that can be used to freely select colors and express variously have been mainly used. However, when a product designed with a selected color on a screen of a specific display is reproduced on another display, the color looks different. In this case, even if the same design, the sensitivity to the product is different. In particular, when Internet commerce is actively conducted, the color difference of each display deteriorates the reliability of the product, which greatly affects the sales volume. Also, in the multimedia society, almost all visual information is recognized through the display, so the importance of accurate color reproduction is realized.

The biggest contributor to this color difference is the inaccurate adjustment of white balance in display manufacturing. In the display, the luminance of light emitted from the screen changes according to the input signal value. For example, when the input signal values of the three primary colors are all 0, the display, that is, the monitor, shows the darkest color, and when the GREEN (G) and BLUE (B) signals value is 0, only the RED (R) signal value is increased. If the R signal value is 255, it gradually shows bright red.

The change rate of the luminance with respect to the input signal value is called a gamma characteristic, and the adjustment of the gamma characteristics of the three primary colors to be the same is called white balance. If the white balance is incorrect, the three R, G, and B curves do not coincide with the input signal values of the entire region as shown in FIG.

As a result, achromatic chromaticity generated when the same amount of signal values of R, G, and B are input is changed depending on the signal value. If the achromatic color has a unique hue according to the white balance adjustment state for each display, the color of all colors is affected. In addition, the chromaticity of white determined by the ratio of the maximum luminance of the three primary colors also varies from display to display.

Therefore, precise adjustment of white balance must be satisfied. However, precise adjustment of white balance in the production line causes a sharp drop in production, causing a price increase.

Accordingly, in the related art, the color difference is reduced by replacing data of a look up table of a VGA embedded in a computer with correction data, but color distortion of the look up table is limited to 256. Accordingly, in recent years, a method and apparatus for measuring color signal voltage output from a VGA and changing it to match the standard data so as to reproduce the full color range compared to the look-up table replacement method have been studied. There is a problem to build (ICC Profile).

An object of the present invention for solving the above problems is to detect the brightness and chromaticity of the color displayed on the screen by directly detecting a predetermined color detection unit on the video signal appearing on the screen and to detect the VGA voltage output from the video card 7 Image display apparatus for detecting color luminance, chromaticity, and VGA voltage with respect to step brightness, and creating a look-up table of output voltages with respect to input voltages based on these, and correcting the color of the display, thereby preventing color difference for each display. The present invention provides a color correction apparatus and method.

1 is a graph showing luminance of three primary colors when white balance is incorrectly adjusted

2 is a block diagram illustrating an image display color correction apparatus according to the present invention.

3A to 3B are flowcharts illustrating a video display color correction method according to the present invention.

* Description of the symbols for the main parts of the drawings *

10: key input unit 20: video card

30 display 40 voltage sensor

50: color measurement unit 60: color signal correction processor

70: control unit

An embodiment of the present invention for solving the above problems will now be described in detail with reference to the accompanying drawings.

2 is a block diagram illustrating a color correction apparatus of an image display according to the present invention.

The video display color correction apparatus according to the present invention includes a key input unit 10 for allowing a user to select various operation modes of a system including a display color correction mode, and a video card outputting a predetermined video signal according to an input operation control signal. 20, a display 30 for displaying a video signal to be recognized by a user, and a voltage sensor 40 for detecting a color signal VGA voltage output from the video card 20 and outputting a corresponding signal. And a color measuring unit 50 measuring the brightness and chromaticity of light emitted from the display 30 and outputting a corresponding signal by controlling an operation by an input operation control signal, and a preset lookup table. The color signal correction processor 60 and the key input unit 10 and the color side for converting and outputting the VGA voltage of the video signal input by the predetermined size. By controlling the operation of the color measurement unit 50 based on the signal output from the unit 50 and the voltage sensor 40, the same as the achromatic color appearing on the display 30 and the VGA output voltage of the achromatic signal for each brightness level A color conversion matrix and a luminance curve are obtained by detecting the luminance and chromaticity of red, green, and blue of the brightness level, respectively, and the color conversion matrix and the luminance curve based on the chromaticity coordinates and gamma values to be output from the key input unit 10. The controller 70 is configured to detect a correction voltage with respect to the VGA output voltage and set a lookup table of the color signal correction processor 60.

On the other hand, in the above-described configuration, the color measurement unit 60 is an optical fiber 62 in contact with the outer surface of the display 30, the diffraction grating 64 for receiving the light transmitted from the optical fiber 62 and scattered for each wavelength, input A CCD (Charge Coupled Device) aligner which receives a light scattered for each wavelength emitted from the diffraction grating 64 to measure the light intensity and outputs a predetermined signal corresponding to the operation controlled according to the operation control signal. 66), an amplifier 67 for amplifying the signal output from the CCD aligner 66 to a predetermined size, and an A / D converter 68 for converting the analog signal output from the amplifier 67 into a digital signal. And a memory 69 for storing signals output from the A / D converter 68.

In the above configuration, the voltage sensor 40 is an A / D converter for converting an input analog voltage into a digital voltage, and the color signal correction processor 50 looks up a digital signal output from the voltage sensor 40. And a processor 52 for converting and outputting the predetermined size into a predetermined size, and a D / A converter 54 for converting the digital voltage output from the processor 52 into an analog voltage.

In addition, in the image display color correction method according to the present invention, the first process of adjusting the contrast and brightness of the display to an optimal state, that is, a state in which the independence of the three primary signals is maintained, and the three primary signal values are all completed when the first process is completed. The achromatic color of constant, i.e., jR = jG = jB is sequentially displayed on the display in a predetermined brightness level, wherein a second process of detecting the VGA output voltage of the three primary color signals outputted from the video card and the second process When finished, red is displayed on the display in the same brightness level as the achromatic color, and the luminance and chromaticity are respectively detected by measuring the intensity distribution for each wavelength of red appearing on the display, and the luminance and the luminance of green and blue are the same. A third process of detecting chromaticity, and the luminance and chromaticity of each color detected in the third process A fourth process of obtaining a color conversion matrix and a luminance curve of three primary colors; and when the fourth process is finished, it is determined whether a user inputs chromaticity coordinates and gamma values of white to be corrected, and when the chromaticity coordinates and gamma values of white are inputted, The color conversion matrix is used to calculate an input signal value where the luminance curves of the three primary colors match the given gamma value in all input signal intervals, and calculate the correction voltage of the VGA output voltage with respect to the VGA output voltage and the corresponding correction voltage. And a fifth process of recording in correspondence with one, and a sixth process of converting and outputting the VGA output voltage output from the VGA card into the correction voltage recorded in the fifth process when the fifth process is completed.

On the other hand, in the above-described configuration, the brightness of the second process and the third process is the seven steps of j is 255, 159, 127, 95, 47, 15, 0 to obtain the VGA output voltage of the seven-step brightness.

Hereinafter, an embodiment of the image display color correction device and method will be described in more detail with reference to FIGS. 3A to 3B.

First, if there is a C / B (Contrast / Brightness) setting mode signal input from the key input unit 10 (S101), the control unit controls the video card 20 based on the signal output from the key input unit 10 as a reference. By outputting a signal, the present application has a display 30 so that the user can adjust the contrast and brightness of the display 30 to an optimal state (a state in which the independence of the three primary color signals is maintained). The C / B pattern pre- filed as -26555 appears, and accordingly, the user adjusts the contrast and brightness of the display 30 to an optimal state (a state in which the independence of the three primary colors signals is maintained) through the key input unit while watching the pattern change. S102).

When the contrast and brightness adjustment of the display 30 is finished as described above, the controller 70 determines whether there is a color signal measurement mode signal input from the key input unit 10 (S103), and if there is a color signal measurement mode signal input, the video card. Outputting the corresponding operation control signal to (20) to display the achromatic color of the R, G, B signal values are all constant, that is, jR = jG = jB sequentially on the display 30 screen in a predetermined step. Achromatic colors of seven levels of brightness, wherein jR = jG = jB (j = 255, 159, 127, 95, 47, 15, 0) are sequentially displayed on the display 30, wherein the output from the video card 20 The VGA output voltages VjR, VjG, and VjB (j = 255, 159, 127, 95, 47, 15, 0) of the three primary color signals of the step are measured by the voltage sensor 40 and input to the controller 70, and the controller ( 70) interpolates on the basis of the VGA output voltage of seven levels of brightness output from the voltage sensor 40 Determined by the voltage of the step 255 (S104).

As described above, when the detection of the VGA output voltage when the R, G, and B signal values are constant, the controller 70 outputs another operation control signal to the video card 20 to display a red [(jR, jG) of seven levels of brightness. , jB) = (255,0,0), (159,0,0), (127,0,0), (95,0,0), (47,0,0), (15,0,0 ), (0,0,0)] is displayed on the screen of the display 30 at a predetermined time interval, and each time a red color appears on the display 30 by outputting a corresponding operation control signal to the color measuring unit 50. By operating the color measurement unit 50, the color measurement unit 50 receives the intensity of each wavelength received through the optical fiber 52, respectively, the red of different brightness appearing at a predetermined time interval through the display 30 By measuring the luminance (YjR) and chromaticities (xi, yi, zi (i = R)) of each of the different red brightness is calculated (S105). When the luminance and chromaticity detection is completed for red as described above, the same process is performed for green and blue (S106) (S107), and the luminances YjR, YjG, YjB and chromaticities xi, yi, zi (i = R, G) of each color are performed. (B) is calculated to obtain a color conversion matrix represented by Equation 1 and luminance curves of three primary colors (S108).

Here, XC, YC, and ZC are the brightness and brightness of FIG. 1 in the display 30 when an arbitrary R, G, B digital signal is input when the contrast and brightness of the display 30 are set to the optimum state and the independence of the three primary colors signals is maintained. According to the curve, when the three primary colors are emitted at the intensity of YR, YG, and YB, the tristimulus values of the mixed colors appearing on the screen, and X0, Y0, and Z0 are the tristimulus values of the desktop when no signal value is input, and xi , yi, zi (i = R, G, B) are the chromaticity coordinates of each of the pure three primary colors with no light on the background. Therefore, intensities YR, YG and YB of three primary colors that can accurately represent a desired color on the screen can be obtained as in Equation 1 above.

Finally, it is determined whether there is a calibration mode signal input from the key input unit 10 (S109), and when there is a calibration mode signal input, the controller 70 returns to the OSD generator (not shown). Outputs an operation control signal to display a window for inputting the chromaticity coordinates and gamma values of the white desired by the user on the screen (S110), and when the chromaticity coordinates and gamma values of the white are input from the key input unit 10. The control unit 70 calculates jR ', jG', and jB 'input signal values in which the luminance curves of the three primary colors match the given gamma values in all input signal intervals using the color conversion matrix represented by Equation 1 above. The VGA output voltage correction voltages Vjr, Vjg, and Vjb are calculated by Equation 2 (only red color) (S112), and the VGA output voltage and the corresponding correction voltage are recorded in the processor 54 (S113).

Where Vmax is the maximum video voltage and Vmin is the minimum video voltage, which varies with VGA.

After this process is executed, the VGA output voltage of the signal value input to the computer is changed to the correction voltage stored in the processor 54 and input to the display 30, so that not only the chromaticity of white but also the chromaticity of all achromatic colors are desired. This allows accurate color reproduction.

Accordingly, according to the present invention, by directly measuring the chromaticity and luminance of the light emitted to the display and controlling the color signal voltage of the display based on this, the user directly measures the color error of the display even if a standard data file of the display is not provided. Not only can white balance be re-adjusted, it also has the advantage that it can be executed at any time when the entire system changes due to display setting or replacement of VGA, etc. Also, color measurement and color signal voltage are automatically controlled so that everyone can use it. Convenience to use is improved, and the setting process maintains the independence of the three primary colors of the brightness and brightness of the display, thereby allowing 28 × 28 × 28 input signals generated by 8 bits of each of R, G, and B. Can be processed with × 3 types of correction data, and color measurement is 255, 159, 127, 9 By performing the 7-step signal value of 5, 47, 15, 0, it is possible to predict the exact result over the entire interval of the input signal value while minimizing the number of measurements, which greatly reduces the memory usage and greatly reduces the setup time. This eliminates the need to build a standard data file for each display for color correction.

Claims (6)

A video card 20 for outputting a predetermined video signal according to an input operation control signal, and a display 30 for displaying a video signal output from the video card 20 so as to be visually recognized by a user. In the video display 30 device, A key input unit 10 for allowing a user to select various operation modes of the system including the display color correction mode; A voltage sensor 40 which detects a color signal VGA voltage output from the video card 20 and outputs a signal corresponding thereto; An operation controlled by an input operation control signal to measure a luminance and chromaticity of light emitted from the display 30 and output a signal corresponding thereto; A color signal correction processor 60 which converts the VGA voltage of the image signal input by the preset lookup table into a predetermined predetermined size and outputs the converted color signal; By controlling the operation of the color measurement unit 50 on the basis of the signals output from the key input unit 10, the color measurement unit 50 and the voltage sensor 40, each brightness step output from the voltage sensor 40 A color conversion matrix and a luminance curve are obtained based on the luminance and chromaticity of the red, green, and blue of the achromatic color and the same brightness level output from the color measurement unit 50 and the VGA output voltage of the achromatic color signal, and from the key input unit 10. The control unit 70 detects a correction voltage with respect to the VGA output voltage using the color conversion matrix and the luminance curve based on the chromaticity coordinate and the gamma value to be corrected, and sets a lookup table of the color signal correction processor 60. Image display color correction device, characterized in that consisting of. The display device of claim 1, wherein the control unit 70 displays an achromatic color, a red color, a green color, and a blue color of the seven levels of 255, 159, 127, 95, 47, 15, and 0 on the display 30 as the video card 20. And outputting a corresponding operation control signal to obtain a VGA output voltage for 255 steps by interpolation based on a VGA output voltage having seven levels of brightness output from the voltage sensor (40). According to claim 1, wherein the color measurement unit 60 is an optical fiber 62 in contact with the outer surface of the display 30, a diffraction grating 64 for receiving the light transmitted from the optical fiber 62 and scattering for each wavelength, input A CCD (Charge Coupled Device) aligner which receives a light scattered for each wavelength emitted from the diffraction grating 64 to measure the light intensity and outputs a predetermined signal corresponding to the operation controlled according to the operation control signal. 66), an amplifier 67 for amplifying the signal output from the CCD aligner 66 to a predetermined size, and an A / D converter 68 for converting the analog signal output from the amplifier 67 into a digital signal. And a memory (69) for storing signals output from the A / D converter (68). The voltage sensor 40 is an A / D converter for converting an input analog voltage into a digital voltage, and the color signal correction processor 50 looks up the digital signal output from the voltage sensor 40. A video display, comprising: a processor 52 for converting and outputting a predetermined size by a table; and a D / A converter 54 for converting a digital voltage output from the processor 52 into an analog voltage. Color Correction Device. In the color correction method of the video display device for displaying a video signal output from the video card so that the user can visually recognize, A first step of adjusting the contrast and brightness of the display to an optimum state, that is, a state in which the independence of the three primary colors signals is maintained; When the first process is completed, the achromatic colors of which all three primary signal values are constant, that is, jR = jG = jB are sequentially displayed on the display in a predetermined brightness level, and at this time, the VGA output voltage of each of the three primary color signals outputted from the video card is detected. A second process of doing; When the second process is completed, red is displayed on the display in the same brightness level as that of the achromatic color, and the luminance and chromaticity of each step appearing on the display are detected, and the luminance and chromaticity of green and blue are measured in the same manner. A third process of detecting each; A fourth process of obtaining a color conversion matrix and a luminance curve of three primary colors based on the luminance and chromaticity of each color detected in the third process; When the fourth process is completed, it is determined whether a user inputs a chromaticity coordinate and a gamma value of white to be corrected, and when a chromaticity coordinate and a gamma value of white are input, a luminance curve of three primary colors in the entire input signal section using the color conversion matrix. A fifth process of calculating an input signal value corresponding to the given gamma value, calculating a correction voltage of the VGA output voltage, and recording the VGA output voltage and the corresponding correction voltage in a 1: 1 correspondence; And a sixth process of converting the VGA output voltage output from the VGA card into the correction voltage recorded in the fifth tablet when the fifth process is completed. The brightness level control method according to claim 5, wherein the brightness of the second and third processes is based on the VGA output voltage having the seven levels of brightness, with j being 255, 159, 127, 95, 47, 15, and 0. An image display color correction method comprising obtaining a voltage for 255 steps by interpolation.