CN1045861C - Color Monitor Color Locking Method - Google Patents

Abstract

A color tracking method for a color monitor, comprising the steps of: (1) corresponding to the control gate (G)₁) Voltage value, calculating R, G, B bias voltage value of three guns, R_b、G_b、B_bSo that the three values satisfy _b-G)∶(G_b-G)∶(B_b-G)=(R_bmin-G_min)∶(G_bmin-G_min)∶(B_bmin-G_min) The conditions of (a); (2) the R obtained in the step (1) is_b、G_b、B_bThe values are respectively output to the bias inputs of R, G, B three guns of a video circuit, so that the color of the monitor does not change with the change of the control grid voltage.

Description

Color Monitor Color Locking Method

The invention relates to a color tracking method for a color monitor.

In a color monitor picture tube (CRT), the outputs of red (R), green (G), and blue (B) must be balanced to produce an intermediate white when the color signal is turned off. Moreover, the ratio of R, G, and B required to produce white must be kept constant from high brightness (Brightness) to low brightness. This kind of control can maintain a certain ratio of R, G, and B output from the brightest part to the dark part of the image, which is called color tracking (Color tracking) or grayscale tracking (grayscale tracking).

Recently, some CRT users, such as computer graphics or typesetters, have higher and higher requirements for color tracking. They hope that the color of the picture will not be changed by the adjustment of brightness or contrast (Contrast). If the color tracking is not correct, at one brightness level, the light field will appear slightly yellow, and at another brightness level, the light field will appear slightly blue.

At present, the existing technology is all to control the brightness of the CRT by adjusting the voltage of the G ₁ point (control grid). Therefore, most manufacturers design the adjustable range of the _G1 voltage to be smaller, or add some compensation circuits to the R, G, and B clamping circuits to prevent the effect of color tracking from being too poor.

The present invention aims at the above-mentioned requirements in the prior art, and provides a method to make the image maintain a certain color under any different brightness conditions.

A color tracking method for a color monitor provided by the present invention includes:

(1) Corresponding to the voltage value of the control grid (G ₁ ), calculate the bias voltage values of R, G, and B guns, R _b , G _b , and B _b , so that these three values satisfy (R _b -G):( G _b -G): (B _b -G)=(R _bmin -G _min ): (G _bmin -G _min ): (B _bmin -G _min );

(2) Output the R _b , G _b , and B _b values obtained in (1) to the bias voltage input terminals of the R, G, and B guns of a video circuit, so that the color of the monitor does not change with the control grid voltage change due to changes.

Further details and advantages of the present invention can be further understood from the following examples and related figures.

Brief description of the drawings:

Fig. 1 is the hardware schematic diagram implementing the method of the present invention;

Fig. 2 is the flowchart of storing related parameters;

Fig. 3 is a flow chart of white balance adjustment;

FIG. 4 is a flow chart of dark balance correction in the present invention.

As shown in Figure 1, it is a hardware block diagram of the relevant part of the present invention in the current general digital color monitor circuit. Wherein, the microcontroller 11 is respectively connected with a program storage device 15, such as an electrically erasable programmable read-only memory (EEPROM), an RS-232 connection interface 19, a monitor front panel (frontpanel) circuit 17, and a monitor video circuit 13 link. The RS-232 connection interface 19 is only connected in the final adjustment and correction stage of the monitor, and this interface can be removed after the adjustment is completed. The usual microcontroller 11 operates according to the program input into the program storage device 15, and uses control lines such as brightness (Brightness) 111, contrast (Contrast) 113, R-bias 115, G-bias 117, B-bias 119. R-driver 112, G-driver 114, and B-driver 116 control the operation of the video circuit 13, and then make the display of the picture tube (CRT) (not shown) meet the user's requirements. If the user wants to adjust the display effect, he can adjust some buttons on the panel, and the adjusted signal can be communicated to the microcontroller 11 through signal lines KEYIN1, KEYIN2, ..., etc., and the microcontroller 11 outputs at least one of the above-mentioned control signals to the video circuit 13.

From the characteristic data of CRT, it can be seen that the effective voltage ratio of R, G, and B guns will remain unchanged for a specific CRT at a specific color temperature. That is,

(Rbmax-Gmax):(Gbax-Gmax):(Bbmax-Gmax)=(Rbmin-Gmin):

(Gbmin-Gmin): (Bbmin-Gmin)=

(Rb-G):(Gb-G):(Bb-G)

Equation (1.1)

Where G _max is the _G1 voltage value when the brightness is controlled to the maximum (max), G _min is the _G1 voltage value when the brightness is controlled to the minimum (min), and G is the _G1 voltage value between the maximum and the minimum.

First, the bias voltage of the green (Green) gun is fixed, so G _bmax = G _bmin for the red (Red) and green (Green) guns, it can be obtained from formula (1.1) (because a/b=c/ d=(ac)/(bd) established) $\frac{\mathrm{Rb}\max -G\max }{\mathrm{GB}\max -G\max }=\frac{\mathrm{Rb}\min -G\min }{\mathrm{GB}\min -G\min }=$ $\frac{\mathrm{Rb}\max -\mathrm{Rb}\min +G\min -G\max }{\mathrm{GB}\max -\mathrm{GB}\min +G\min -G\max }=$ $\frac{(\mathrm{Rb}\max -\mathrm{Rb}\min )+(G\min -G\max )}{G\min -G\max }=\frac{(\mathrm{Rb}\max -\mathrm{Rb}\min )}{G\min -G\max }+1$ Formula (1.2)

It is thus found that if the bias voltages of the red (RED), green (Green) and blue (Blue) guns are controlled in the following formula (1.3) during the change of brightness, then the relation of formula (1.1) can be maintained, and Keeps the color temperature at that specific color temperature; that is, the color temperature does not change. $\mathrm{Rb}=\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\max -G\min }(G-G\min )+\mathrm{Rb}\min ,$

Gb=Gbmax=Gbmin $\mathrm{Bb}=\frac{\mathrm{Bb}\max -\mathrm{Bb}\min }{G\max -G\min }(G-G\min )+\mathrm{Bb}\min$ Formula (1.3)

It is hereby certified that: $\frac{\mathrm{Rb}-G}{\mathrm{GB}-G}=\frac{\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\max -G\min }(G-G\min )+\mathrm{Rb}\min -G}{\mathrm{GB}-G}=$ $\frac{\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\max -G\min }(G-G\min )+(G\min -G)+(\mathrm{Rb}\min -G\min )}{(G\min -G)+(\mathrm{GB}\min -G\min )}=$ $\frac{\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\min -G\max }(G\min -G)+(G\min -G)+(\mathrm{Rb}\min -G\min )}{(G\min -G)+(\mathrm{GB}\min -G\min )}$ Formula (1.4)

By (1.2) formula $\frac{\mathrm{Rb}\min -G\min }{\mathrm{GB}\min -G\min }=\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\min -G\max }+1,$ have to $\frac{\mathrm{Rb}\min -G\min }{\mathrm{GB}\min -G\min }=$ $\frac{\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\min -G\max }(G\min -G)+(G\min -G)}{(G\min -G)}=$ $\frac{\frac{\mathrm{Rb}\max -\mathrm{Rb}\min }{G\min -G\max }(G\min -G)+(G\min -G)+(\mathrm{Rb}\min -G\min )}{(G\min -G)+(\mathrm{Rb}\min -G\min )}$ Formula (1.5)

[Because a/b=c/d=(a+c)/(b+d) is established]

Factor (1.5) is equal to (1.4), so we get $\frac{\mathrm{Rb}-G}{\mathrm{GB}-G}=\frac{\mathrm{Rb}\min -G\min }{\mathrm{GB}\min -G\min }$ Formula (1.6)

Similarly, it can be proved $\frac{\mathrm{Bb}-G}{\mathrm{GB}-G}=\frac{\mathrm{Bb}\min -G\min }{\mathrm{GB}\min -G\min }$ Formula (1.7)

From (1.6), (1.7) formula, available (Rb-G): (Gb-G): (Bb-G) = (Rbmin-Gmin): (Gbmin-Gmin): (Bbmin-Gmin) formula (1.8 )

Therefore, when the brightness changes with the G value, as long as the microprocessor 11 controls the video circuit 13 according to (1.3), the effective voltage ratio of the three guns can be kept unchanged, and the color temperature does not change accordingly.

The calculation and storage process of _the required parameter values R _bmax , G _bmax , B _bmax , R _bmin , G _bmin , _{and B bmin in} formula ₍ 1.3) are described below.

In the dark balance adjustment program in Figure 2, first adjust the brightness control knob to max (box 21), and then adjust the bias voltages of the R, G, and B guns so that the color temperature of the CRT reaches the first specified color temperature under the brightness specified in the specification (Block 23), then the current R, G, B bias voltage values, R _bmax , G _bmax , B _bmax , are stored in the ROM 15 via the signal line SDA (Block 25).

As shown in Figure 3, it is a well-known white balance adjustment procedure. First, adjust the brightness control knob to max (box 31) and then adjust the drive voltages of the R, G, and B guns so that the color temperature of the CRT reaches the specification. The specific color temperature (block 33) of the predetermined brightness, then the R, G, B driving voltage R _d , G _d , B _d at this time, the value is stored in the read-only memory 15 by the signal line SDA (square block Box 35).

Then, make a dark balance correction, as shown in Figure 4, that is, adjust the brightness control knob to min (box 41), and then set the bias value of a certain gun (such as G gun) to make it equal to G _bmax (box 43), then adjust the other two guns, which are the bias voltage values of the R and B guns at this time, so that the CRT reaches the specific color temperature (box 45) mentioned in the aforementioned dark balance program, and then the R at this moment , G, B bias voltages, R _bmin , G _bmin , B _bmin are stored in the ROM 15 by the signal line SDA (block 47). But at this time, G _bmin =G _bmax .

Once the user adjusts the brightness control button to change the voltage at point _G1 , the microcontroller 11 generates a set of new R, G, and B bias values, R _b , G _b , and B _b , according to formula (1.3), and then sets These three values are output to the video circuit 13 by using the signal lines R-bias, G-bias, and B-bias to change the brightness, and the formula (1.1) still holds true. And according to the characteristic of CRT, the change of brightness still can not change the color temperature of CRT, and reach the object of the present invention.

Claims (2)

1. A color monitor color tracking method is characterized in that it comprises the following steps: (1) Corresponding to the voltage value of the control grid _G1 , calculate the bias voltage values of the three guns R, G, and B, R _b , G _b , and B _b , so that these three values satisfy (R _b -G): (G _b -G): (B _b -G)=(R _bmin -G _min ): (G _bmin -G _min ): (B _bmin -G _min ); (2) Output the R _b , G _b , and B _b values obtained in (1) to the bias voltage input terminals of the R, G, and B guns of a video circuit, so that the color of the monitor does not follow the control grid. Change to change. 2. The color monitor color tracking method according to claim 1, wherein the following formula calculates R _b , G _b , B _b $\mathrm{Rb}=\frac{\mathrm{Rb}\max +\mathrm{Rb}\min }{G\max -G\min }(G-G\min )+\mathrm{Rb}\min$ Gb=Gbmax=Gbmin $\mathrm{Bb}=\frac{\mathrm{Bb}\max -\mathrm{Bb}\min }{G\max -G\min }(G-G\min )\mathrm{Bb}\min ,$ Among them, G _max is the G ₁ voltage value when the brightness is controlled to the maximum, G _min is the G ₁ voltage value when the brightness is controlled to the minimum, G is the G ₁ voltage value when the brightness is controlled between the maximum and the minimum, R _bmax , G _bmax , B _bmax is the bias voltage value of the three guns R, G, and B that make the color temperature of the monitor reach a specific color temperature under the specified brightness when the brightness control is adjusted to the maximum, and R _bmin , G _bmin , and B _bmin are brightness control adjustments To the minimum, make the monitor reach the bias value of the R, G, B three guns of the aforementioned specific color temperature.

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