JP2009177569A - Liquid crystal video display device, and white balance control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, in a conventional white balance control method, since white balance is controlled in a fixed R(red), G(green), B(blue) luminance ratio with respect to a video luminance change, a control result may be shifted from target white balance with respect to the video luminance change. <P>SOLUTION: A lightness/chrominance detector is used to measure and acquire, at a plurality of points, tristimulus values of R(red), G(green), B(blue) of a video image projected (to acquire V-T characteristics of an LCD panel with the tristimulus values). A tristimulus value at a middle point between a measuring point and a measuring point is linearly interpolated. In order to obtain a target luminance factor characteristics, a Y stimulus value of G(green) is used as a representative, arithmetic is performed to make the Y stimulus value of G(green) be the target luminance factor characteristics, and a gamma correction value is obtained from the obtained three stimulus values. Further, in order to obtain target chrominance values x and y, three stimulus values of R(red), B(blue) are determined by arithmetic and similarly to G(green), gamma correction values of R(red), B(blue) are obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device that displays a color image using a liquid crystal panel and a white balance control method thereof.

In the conventional white balance control method, the liquid crystal display device itself has a signal generator for white balance adjustment, and adjustment is performed using the signal.
In the adjustment method, a luminance ratio of R (red), G (green), and B (blue) for achieving a target white balance is obtained in advance, and a signal for the adjustment is projected to obtain R (red). ), G (green), and B (blue) are adjusted so that the luminance ratio becomes the target ratio. (For example, refer to Patent Document 1).
JP 2005-57647 A

In the conventional white balance control method, the white balance is controlled by the luminance ratio of R (red), G (green), and B (blue). However, the color temperature changes according to the luminance in this white balance. If the adjustment is made only with the fixed luminance ratio of R (red), G (green), and B (blue), the change in luminance of the image deviates from the target white balance.
An object of the liquid crystal display device of the present invention is to provide a liquid crystal display device that can be adjusted to a target white balance regardless of how the brightness of the image changes.

In order to achieve this object, the liquid crystal display device of the present invention is
A video display unit for projecting and displaying a video signal and a video signal used for white balance control are generated, and a video signal control unit for outputting an input video signal to be output to the video display unit and an output video signal projected on the screen are divided into three. The light output detector that outputs data that can be output as a stimulus value or that can be converted to a tristimulus value and the tristimulus value obtained from this light output detector, or the data obtained from the light output detector is converted to a tristimulus value. Using the converted data, R (red), G (green), and B (blue) gamma correction values are calculated, and a white balance control unit that controls a target white balance and an R generated by the white balance control unit. The gamma correction value storage unit for recording the (red), G (green), and B (blue) gamma correction values, the target white balance, and the target luminance rate characteristic are recorded in advance. It performs control of the white balance by the value recording unit. As a result, the intended purpose can be achieved.

As described above, according to the present invention, the liquid crystal display device of the present invention is
Using a brightness and chromaticity detection device, measure and acquire the tristimulus values of R (red), G (green), and B (blue) of the projected image at multiple points. Get by stimulus value). A straight line is interpolated between the measurement points. In order to obtain the target luminance rate characteristic, the G (green) Y stimulus value is represented as a representative, and the G (green) Y stimulus value is calculated to be the target luminance rate characteristic, and the obtained tristimulus value is obtained. Get the gamma correction value. Furthermore, in order to obtain target chromaticity values x and y, tristimulus values of R (red) and B (blue) are obtained by calculation, and R (red) and B (blue) are calculated in the same manner as G (green). Get the gamma correction value. By controlling the white balance by this method, it is possible to provide a liquid crystal display apparatus in which the white balance does not deviate from the target white balance even when the luminance of the image changes.

Hereinafter, embodiments of a liquid crystal display device of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
In the first embodiment, specific white balance adjustment / control will be described.

  FIG. 1 shows a configuration diagram of a liquid crystal display device of the present invention.

In the liquid crystal display device of the present invention,
The light output detection unit 5 is installed at a position where the video signal can be detected on the video display unit 20 that displays and displays the video signal.

The light output detection unit 5 is a sensor element that can measure tristimulus values of light or light information that can be converted into tristimulus values, such as chromaticity value and luminance. There is a video signal control unit 4 capable of projecting an arbitrary signal to the light output detection unit 5, and the video signal control unit 4 controls the white balance and luminance of the video with respect to the light output detection unit 5. A video signal necessary for this is generated and displayed on the video display unit 20.
Video signals necessary for controlling the white balance include a white video signal for indicating the maximum luminance, a black video signal for indicating the minimum luminance, R (red), G (green), and B (blue). R (red), G (green), and B (blue) video signals for indicating the maximum luminance of the image, and R (red), G (green), and B (blue) for each arbitrary luminance R (red), G (green), B (blue) video signals, and R (red), G (green), R (red), G A video signal of an arbitrary color composed of a combination of video signals of (green) and B (blue) is generated by the video signal control unit 4 and displayed on the video display unit 20.

  The video signal is output from the light output detection unit 5 as tristimulus values corresponding to the video signal or information that can be converted into tristimulus values.

  This information is received by the white balance control unit 6 and compared with the white balance and luminance information recorded in advance in the target value storage unit 8 to calculate information for controlling the white balance and luminance of the video. The calculated information for controlling the color and brightness of the video is called a gamma correction value, and there are gamma correction values for R (red), G (green), and B (blue). The gamma correction value is recorded in the gamma correction value storage unit 7 and is used by the video signal control unit 4 when displaying a television signal or the like. As a result, the liquid crystal display device of the present invention can obtain a target white balance regardless of how the luminance changes.

Similarly, FIG. 2 shows a configuration diagram of a liquid crystal display device of the present invention.
A light source 1;
The illumination light from the light source 1 is split into R (red), G (green), and B (blue) for projection.

The split three primary color lights and the video signal from the video signal control unit 4 are combined in the video conversion unit 2 and projected onto the screen 3 as video information output.
On the screen 3, a light output detector 5 is installed at a position where a video signal projected on the screen can be detected.

The light output detection unit 5 is a sensor element that can measure tristimulus values of light or light information that can be converted into tristimulus values, such as chromaticity value and luminance.
There is a video signal control unit 4 capable of projecting an arbitrary signal to the light output detection unit 5, and the video signal control unit 4 controls the white balance and luminance of the video with respect to the light output detection unit 5. A video signal necessary for this is generated and projected through the video converter 2.
Video signals necessary for controlling the white balance include a white video signal for indicating the maximum luminance, a black video signal for indicating the minimum luminance, R (red), G (green), and B (blue). R (red), G (green), and B (blue) video signals for indicating the maximum luminance of the image, and R (red), G (green), and B (blue) for each arbitrary luminance R (red), G (green), B (blue) video signals, and R (red), G (green), R (red), G A video signal of an arbitrary color composed of a combination of video signals of (green) and B (blue) is generated by the video signal control unit 4 and projected through the video conversion unit 2.

  The projected video signal is projected onto the light output detection unit 5, and the light output detection unit 5 outputs tristimulus values corresponding to the video signal or information that can be converted into tristimulus values.

This information is received by the white balance control unit 6 and compared with the white balance and luminance information recorded in advance in the target value storage unit 8 to calculate information for controlling the white balance and luminance of the video. The calculated information for controlling the color and brightness of the video is called a gamma correction value, and there are gamma correction values for R (red), G (green), and B (blue). The gamma correction value is recorded in the gamma correction value storage unit 7 and is used by the video signal control unit 4 when displaying a television signal or the like. As a result, the liquid crystal display device of the present invention can obtain a target white balance regardless of how the luminance changes.
A flowchart of this white balance and luminance control method is shown in FIG.
The details of the white balance and luminance control method shown here will be described for the liquid crystal display device having the configuration shown in FIG.

  In the first step, a video signal necessary for white balance control (in this white balance control, a gamma correction value is generated, and brightness control is also performed simultaneously with consent) is sent to the video conversion unit 2 by video signal control. Supplied from section 4.

  In the second step, this video signal is detected as a tristimulus value output or information that can be converted into a tristimulus value by the light output detector 5 that is projected and attached to the screen 3 as an output video signal. At this time, the output video signal is a white video signal in which R (red), G (green), and B (blue) all indicate maximum luminance, and all of R (red), G (green), and B (blue) are minimum. Black video signal indicating luminance, R (red), G (green), B (blue) video signals and R (red) to indicate the maximum luminance of each of R (red), G (green), and B (blue) Red, G (green) and B (blue) are video signals of a plurality of points between R (red), G (green) and B (blue) video signals for indicating the minimum luminance. Is output as tristimulus value output by the light output detector 5 or as information that can be converted into tristimulus values.

  In the third step, the Y stimulus value among the G (green) tristimulus values is linearly complemented, converted into a target luminance rate characteristic, and the G (green) gamma correction value is calculated. The calculation method is described below.

  First, a function used in the calculation of the third step is defined.

Of the signals necessary for white balance control, the video signal between the maximum luminance and the minimum luminance is divided into a plurality of points. The plurality of points are set to 0, 1, 2 ... n ... n-max,
The input signal of the video signal control unit 4 is fi (n),
The output signal of the video signal control unit 4 is fo (n),
The gamma correction value for G (green) is G-Gamma (n).

For example, assuming that the signal input to the video signal control unit 4 is 10 bits and the output signal is 10 bits, and n-max is 64, the 10-bit signals of each input / output are divided into 64 equal parts.
Based on the above example, fi (64) = 1023
fo (64) = 1023
Since the gamma correction value is the look-up table data of the output signal fo with respect to the input signal fi to the video signal control unit 4, the output signal fo (n) of the G (green) video signal control unit 4 after the gamma correction is applied. It is expressed as shown in Equation 1.

  Further, the target luminance rate characteristic is recorded in the target value storage unit 8. The luminance rate characteristic is the ratio of the luminance of the white signal detected by the light output detector 5 to the signal fi (n) input to the video signal controller 4.

  Here, if the contents of the first step and the second step are supplemented, the video signal supplied to the video conversion unit 2 from the video signal control unit 4 necessary for white balance control, which is output in the first step. Is a video signal fo (n) from 0 point to “n-max” point of each RGB, and the discrete data detected in the second step is the dynamic range of the signal processed by the video signal processing unit. The video signal fo (n) output in the first step, which is discretely divided at multiple points from 0 to n-max, that is, the signal level is different for each point, outputs the light projected on the screen as light output The data measured by the detection unit 5 is obtained.

Among the G (green) tristimulus values obtained by measurement, the Y stimulus value is defined as LG (n). The value obtained by subtracting the value of LG (0) at the 0th point from LG (n) is referred to as L′ G (n).
L'G (n) is defined as Equation 2.

  Based on this number 2, among G (green) tristimulus values, G (green) transmittance characteristics represented by Y stimulation values are defined as ftx (n), and G (green) transmittance characteristics ftx (n) is expressed as shown in Equation 3.

(%)
The target luminance rate characteristic is expressed as ft (n) (%), where fi (n) is the input signal.
According to the following calculation formula, the Y stimulus value of the tristimulus value of G (green) is converted into the target luminance rate characteristic. The G (green) gamma correction value fo (n) is obtained by this calculation formula.
When determining the gamma correction value fo (n) of the “n” point, ft (n) and ftx (n) are compared to perform case classification. The calculation is performed in the direction of decreasing from n = max.

When ftx (n)> ft (n)
Compare ft (n) with ftx (n-1), ftx (n-2) ...
Find the value of α such that ft (n)> ftx (α). (Find the place where ftx (n)> ft (n) reverses)
The gamma correction value for G (green) is calculated as shown in Equation 4.

If ftx (n) <ft (n)
Compare ft (n) with ftx (n + 1), ftx (n + 2) ...
A β value satisfying ft (n) <ftx (β) is obtained. (Search where ftx (n) <ft (n) reverses)
The G (green) gamma correction value is calculated as shown in Equation 5.

When ftx (n) = ft (n), the G (green) gamma correction value is calculated as shown in Equation 6.

  As described above, the G (green) gamma correction value G-Gamma (n) is obtained by dividing the three cases for all points. Using the same calculation formula, the tristimulus value of G (green) at the “n” point is calculated. The tristimulus values stopped here are also used as reference data when calculating the white balance.

  By the fourth step, the tristimulus values of R (red) and B (blue) that become the target white balance for the tristimulus values of G (green) in a specific gradation “n” of G (green) are obtained. Calculation is performed with linear interpolation, and R (red) and B (blue) gamma correction values are calculated from the tristimulus values. The calculation method is described.

First, the CIE chromaticity indicating the target white balance value at the point “n” where the calculation for defining the parameter used in the calculation in the fourth step is performed is x (n) and y (n).

  In general, the relationship of Equations 7 and 8 is established between the CIE chromaticity x, y and the tristimulus values X, Y, Z.

  The chromaticity values xo (n) and yo (n) indicating the white balance at each adjustment point “n” are expressed by Equations 9 and 10.

  Here, XRl, YRl and ZRl are tristimulus values of R (red), and l is data obtained by linearly complementing the tristimulus values of R (red) obtained in the second step to the maximum resolution of fo. To do. If it is 10 bits, it is a value from 0 to 1023.

  For example, in the case of n-max = 64, the 10-bit signal is divided into 64 equal parts, and is divided by 16 steps in decimal conversion. Therefore, data of l (n) = 16 × n is measured by the second step. Here, values other than l (n) = 16 × n, for example, tristimulus values when l = 24 are tristimulus values when l (1) = 16 and tristimulus values when l (2) = 32. This is the middle data.

  Similarly, XBm, YBm, and ZBm are B (blue) tristimulus values, and m is data obtained by linearly complementing the B (blue) tristimulus values obtained in the second step to the maximum resolution of fo. . If it is 10 bits, it is a value from 0 to 1023. Therefore, the tristimulus value data obtained in the second step is a value obtained by calculating data for all fo using linear interpolation.

  Since the green tristimulus value of Point “n” has already been obtained by the calculation in the third step, it can be treated as a fixed value. When rearranged, they are expressed as Equations 11 and 12.

  The above formulas 11 and 12 are calculated as the following formulas 13 and 14 in consideration of the characteristics of the projection in which the light emitted from the RGB three-color panel is mixed and output. In this way, low tone is calculated systematically.

  The R (red) and B (blue) tristimulus values XRl, YRl, ZRl and XBm, YBm, ZBm obtained by the above-described linear interpolation are all substituted to calculate the chromaticity value of the point “n”.

  For example, when the input / output signal is 10 bits, l and m are 1024 data, and the calculated chromaticity values xo (n) and yo (n) indicating white balance are 1024 × 1024 1048576 data. . However, if the number of points n-max measured in the second step is already 1023 points, a higher resolution cannot be obtained. It is meaningful to perform linear interpolation when measuring the second step with a point smaller than the resolution of the input / output signal.

  To check how far xo (n), yo (n) and chromaticity values x (n), y (n) indicating the target white balance are separated, xo (n), yo A distance Δ indicating the distance between (n) and the chromaticity values x (n) and y (n) indicating the target white balance is calculated by Equation 15.

  A combination of l and m is selected such that the distance Δ obtained in the above equation 15 is the minimum value. Since l and m are obtained for each point “n”, when R (red) and B (blue) gamma correction values are R-Gamma (n) and B-Gamma (n), R-Gamma (n ) And B-Gamma (n) are calculated by Equations 16 and 17.

As a result, R (red) and B (blue) gamma correction values are obtained.
By these calculations, R (red), G (green), and B (blue) gamma correction values R-Gamma (n), G-Gamma (n), and B-Gamma (n) are all obtained.

The gamma correction value obtained in the fifth step is stored in the gamma correction recording device unit 7.
The gamma correction value stored here is used by the video signal processing unit 4 and the gamma correction value is used as the look-up table data of the output signal fo with respect to the input signal fi to the video signal control unit 4. The video display device can obtain the target white balance regardless of how the luminance changes.
(Embodiment 2)
In the second embodiment, a method for performing the calculation of the gamma correction value for adjusting and controlling the white balance in the first embodiment more efficiently will be described.

  FIG. 4 shows a flowchart for performing more efficiently when calculating a gamma correction value for white balance adjustment / control in the liquid crystal display apparatus having the same configuration as that of the first embodiment.

  In the first step, the second step, and the third step, the same steps as in the first embodiment are performed. See Embodiment Mode 1 for details.

  By the fourth step, the tristimulus values of R (red) and B (blue) that become the target white balance for the tristimulus values of G (green) in a specific gradation “n” of G (green) are obtained. Calculate without straight line interpolation. The calculation method is described.

First, the CIE chromaticity indicating the target white balance value at the point “n” where the calculation for defining the parameter used in the calculation in the fourth step is performed is x (n) and y (n).

  In general, the relationship of Equations 18 and 19 is established between the CIE chromaticity x, y and the tristimulus values X, Y, Z.

  The chromaticity values xo (n) and yo (n) indicating the white balance at each adjustment point “n” are expressed by equations 20 and 21.

  Here, XRn ', YRn', ZRn 'are R (red) tristimulus values, and n' is the Point used in the second step. Similarly, XBn ″, YBn ″ and ZBn ″ are the tristimulus values of B (blue), and n ″ is the Point used in the second step.

    Since the green tristimulus value of Point “n” has already been obtained by the calculation in the third step, it can be treated as a fixed value. When rearranged, they are expressed as Equation 22 and Equation 23.

  In consideration of the characteristics of the projection in which the light emitted from the RGB three-color panel is mixed and outputted, the above formulas 22 and 23 are calculated as the following formulas 24 and 25. In this way, low tone is calculated systematically.

  The R (red) and B (blue) tristimulus values XRn ', YRn', ZRn 'and XBn ", YBn", ZBn "measured in the second step are all substituted into Point" Calculate the chromaticity value of n ”.

  To check how far xo (n), yo (n) and chromaticity values x (n), y (n) indicating the target white balance are separated, xo (n), yo (n) A distance Δ indicating the distance between (n) and the chromaticity values x (n) and y (n) indicating the target white balance is calculated by Equation 26.

  A combination of n ′ and n ″ is selected so that the distance Δ obtained in the above equation 26 is the minimum value. N ′ and n ″ are obtained for each point “n”.

  As a supplement, when the maximum value n-max, n'-max, n "-max measured in the second step is sufficiently large in the above calculation system, for example, when the input / output signal is 10 bits If the maximum values n-max, n′-max, and n ″ -max of each point are 1024, the following steps are not necessary. When the maximum value n-max, n′-max, n ″ -max of each point is 64 or the like, it is meaningful in the following steps.

  When the distance Δ obtained in the above equation 26 is larger than the specified numerical value, it is determined that the white balance calculation is insufficient.

In the fifth step, R (red) and B (blue) points n ′ and n ″ obtained in the fourth step are used as centers.
n '± p (p is a specified integer)
n ”± q (q is a specified integer)
The tristimulus values of the point are divided by linear interpolation and the resolution of the input / output signal is maximized.
The output values of the divided points are defined as l ′ and m ′. Synonymous with l and m in the first embodiment.
The chromaticity values xo (n) and yo (n) indicating the white balance are again calculated by Equations 27 and 28.

  To check how far xo (n), yo (n) and chromaticity values x (n), y (n) indicating the target white balance are separated, xo (n), yo (n) A distance Δ ′ indicating the distance between (n) and the chromaticity values x (n) and y (n) indicating the target white balance is calculated by Equation 29.

  A combination of l ′ and m ′ is selected such that the distance Δ ′ obtained in the above equation 29 is the minimum value. Since l 'and m' are obtained for each point “n”, R-Gamma (n) and B-Gamma (n) are used as R-Gamma (n) and R-Gamma (n). (n) and B-Gamma (n) are calculated by Equation 30 and Equation 31.

  As a result, R (red) and B (blue) gamma correction values are obtained.

  By these calculations, R (red), G (green), and B (blue) gamma correction values R-Gamma (n), G-Gamma (n), and B-Gamma (n) are all obtained. By limiting the range for linear interpolation, white balance can be calculated efficiently with the same accuracy.

The gamma correction value obtained in the sixth step is stored in the gamma correction recording device unit 7.
The gamma correction value stored here is used by the video signal processing unit 4 and the gamma correction value is used as the look-up table data of the output signal fo with respect to the input signal fi to the video signal control unit 4. The video display device can obtain the target white balance regardless of how the luminance changes.

  Furthermore, if this method is used, the gamma correction value for controlling the white balance can be calculated more quickly.

In both the first embodiment and the second embodiment, the tristimulus values are discretely measured by a plurality of points in the second step. The plurality of points are equally divided into n as described above to determine the measurement points. However, in order to shorten the adjustment time in the white balance control, n is reduced. Or, extract only the necessary points from n equally divided points, and close to a certain point, not equally. By deciding roughly near a point, it is possible to efficiently collect necessary information and use it for calculations.
(Embodiment 3)
In the third embodiment, after the calculation of the gamma correction value for adjusting and controlling the white balance in the first and second embodiments, and when the calculation result deviates more than a certain value, it is prepared in advance. By replacing it with the gamma correction value for adjustment compensation, it is possible to maintain a natural change in appearance even if the adjustment is shifted. This method is shown in the flowchart of FIG.

In the first step, the second step, and the third step, the same steps as in the first embodiment are performed. See Embodiment Mode 1 for details.
In the fourth step, the X stimulus value among the R (red) tristimulus values is linearly complemented, converted to the target luminance rate characteristic, and the R (red) adjustment complement gamma correction value is calculated.

  The calculation method is the same as in the third step, and the third step uses the Y stimulus value among the G (green) tristimulus values to calculate the G (green) gamma correction value. In step 4, calculation is performed using the X stimulus value among the tristimulus values of R (red).

The obtained result is temporarily stored for later use as an R (red) adjustment complement gamma correction value.
In the fifth step, the Z stimulus value among the B (blue) tristimulus values is linearly complemented, converted into a target luminance rate characteristic, and the B (blue) adjustment complement gamma correction value is calculated.

  The calculation method is the same as in the third step, and the third step uses the Y stimulus value among the G (green) tristimulus values to calculate the G (green) gamma correction value. In step 4, calculation is performed using the Z stimulus value among the B (blue) tristimulus values.

The obtained result is temporarily stored as a G (blue) adjustment complement gamma correction value for later use.
In the sixth step, R (red) and B (blue) gamma correction values R are calculated in the same manner as in the fourth step of the first embodiment or the fourth step and the fifth step of the second embodiment. -Gamma (n) and B-Gamma (n) are calculated. The minimum value of the distance value (distance Δ obtained by Equation 15 of Embodiment 1, distance Δ ′ obtained by Equation 26 of Embodiment 2) used when obtaining the final calculation result in this step is determined in advance. When the point “r” is larger than the preset value, and the point “r” is larger than the preset point, the R (red) gamma correction value of the point larger than the point “r” R-Gamma ( The value of n) is replaced with the R (red) adjustment complement gamma correction value obtained in the fourth step. Similarly, the B (blue) gamma correction value B-Gamma (n) of Point larger than Point “r” is replaced with the B (blue) adjustment complement gamma correction value obtained in the fifth step.

The gamma correction value obtained in the seventh step is stored in the gamma correction recording device unit 7.
The gamma correction value stored here is used by the video signal processing unit 4 and the gamma correction value is used as the look-up table data of the output signal fo with respect to the input signal fi to the video signal control unit 4. The video display device naturally changes the white balance up to the maximum brightness of the device even if the target brightness rate characteristics do not match the characteristics of the LCD panel and the white balance deviates from the target value. You can get a white balance that doesn't give you a sense of incompatibility.

  The liquid crystal display device of the present invention has an effect that the target white balance can be obtained regardless of how the luminance changes, and is useful in the field of image control of the liquid crystal display device. is there.

Configuration diagram of liquid crystal display device of the present invention Configuration diagram of liquid crystal display device of the present invention Flowchart of white balance control method of the present invention Flowchart of white balance control method of the present invention Flowchart of white balance correction method of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Image | video conversion part 3 Screen 4 Image | video signal control part 5 Light output detection part 6 White balance control part 7 Gamma correction value memory | storage part 8 Target value memory | storage part 20 Image | video display part

Claims (4)

A video display unit for displaying and displaying a video signal;
A video signal control unit that generates a video signal used for white balance control and outputs an input video signal to be output to the video display unit;
An output video signal projected on the screen as a tristimulus value, or a light output detector that outputs data that can be converted to a tristimulus value;
Using the tristimulus values obtained from this light output detection unit or the data obtained by converting the data obtained from the light output detection unit into tristimulus values, gamma of R (red), G (green), and B (blue) A white balance control unit that calculates a correction value and controls a target white balance;
A gamma correction value storage unit for storing gamma correction values of R (red), G (green), and B (blue) generated by the white balance control unit;
A target value storage unit for storing the target white balance and the target luminance rate characteristic;
A liquid crystal display device comprising: The video display unit includes a light source,
A video conversion unit that synthesizes the illumination light from this light source and the input video signal and converts them into video information;
Consists of a screen on which the output signal from this video converter is projected,
The liquid crystal display device according to claim 1. A first step of outputting an input video signal from the video signal control unit to the video display unit;
A second step of discretely measuring and acquiring tristimulus values from the display image;
A third step of linearly complementing the Y stimulus value among the tristimulus values of G (green), converting it to a target luminance rate characteristic, and calculating a gamma correction value of G (green);
For the G (green) tristimulus values in the specific tone of G (green) above, the R (red) and B (blue) tristimulus values that are the target white balance are calculated by linear interpolation, A fourth step of calculating R (red) and B (blue) gamma correction values from the tristimulus values;
A white balance control method for controlling white balance in a fifth step of storing the obtained R (red), G (green), and B (blue) gamma correction values in a storage device. A first step of outputting an input video signal from the video signal control unit to the video display unit;
A second step of discretely measuring and acquiring tristimulus values from a display shot image;
A third step of linearly complementing the Y stimulus value among the tristimulus values of G (green), converting it to a target luminance rate characteristic, and calculating a gamma correction value of G (green);
Combination of G (green) tristimulus values in a specific tone of G (green) and a combination of measured R (red) and B (blue) tristimulus values close to the target white balance Selecting a fourth step;
G (green) tristimulus value at a specific tone of G (green) by linearly complementing the tristimulus values of the selected R (red) and B (blue) measurement points and the adjacent points. In this case, the R (red) and B (blue) tristimulus values for the target white balance are calculated, and the R (red) and B (blue) gamma correction values are calculated from the tristimulus values. And the process of
A white balance control method for controlling white balance in a sixth step of storing the obtained R (red), G (green), and B (blue) gamma correction values in a storage device.