JPH0362794A - Color balance adjusting device for color monitor - Google Patents

Abstract

PURPOSE:To compensate a secular change in color balance and brightness with high accuracy and simple constitution by adjusting a level of each color signal circuit system based on a difference between a current measurement of brightness for each color and a stored measurement at the initial state of a color monitor. CONSTITUTION:A control signal generating circuit 58 stores a reference value of black and white level signals in each color component circuit system after color balance adjustment. When the color monitor is set initially and in actual operation and the adjustment of color balance is needed, an adjustment switch 60 is turned on. Then the control signal generating circuit 58 compares the black and white level for each color component with a reference value. when a latch data is, e.g. higher than a sensor output, a positive black level adjustment signal corresponding to the difference is generated to increase the pedestal level. Thus, the black level of each color signal system is always coincident with the initial state whose color balance is matched and the secular change in the color balance and brightness is compensated.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a color monitor that automatically adjusts the color balance and brightness of a color monitor) <Rance 7Jl! 11 Regarding the adjustment device.

[Conventional technology]

In recent years, color monitors have been used to simulate images in various fields. For example, in the fields of printing and plate making, the actual finished state is simulated in advance using a color monitor. In such cases, color monitors are required to have very strict color viscosity.

In particular, white is easy for humans to distinguish, and if the white 7<lance is out of alignment, it will be noticeable. The main purpose of plate-making machines is to see colors, and an imbalance in color on a color monitor can be fatal.

Here, the difference in color balance is the G of the color monitor.

Detection is achieved by manually inputting test waveforms having gradations that change stepwise from white to black to the B and R color component signal input terminals. In other words, originally, the screen is reproduced as a gray scale, which has gradations from white to black.
If the color balance is off, the image will be reproduced in this gray scale or with a tinge of color.

The color balance of a color monitor may shift due to thermal factors such as heat generated by the color monitor itself or changes in ambient temperature, or due to factors over time.B.

A difference in amplification may occur between the width circuits of each GR color signal system, and the operating point of the cathode ray tube may change.

- Deterioration of the color balance of the color monitor occurs over time within the film.

None of the conventional color monitors is equipped with a device that automatically corrects color balance, so if the color balance deteriorates, the only option is to manually adjust it using the color adjustment function included in the color monitor.

For this reason, the human eye notices the color balance after it has deteriorated to a certain extent, and then makes adjustments, which takes a long time to respond to the problem.This results in the use of the plate for a long period of time with the color balance deteriorated, which greatly affects the quality of the plate-making process. It had a great influence.

Recently, there have been some models that fix an optical sensor on the surface of a color monitor during adjustment, detect the color balance according to the output of this sensor, and automatically adjust the color balance if it is out of alignment. Although it has been developed, it is a hassle to attach a sensor each time an adjustment is made and then remove it again after making an adjustment.

Note that not only color balance but also luminance is similarly affected by changes over time, and it is also necessary to compensate for changes in luminance over time.

[Invention or problem to be solved]

This invention was made to deal with the above-mentioned circumstances,
It is an object of the present invention to provide a color balance adjustment device for a color monitor that can easily adjust envelope balance and brightness at any time and compensate for changes over time without requiring the sensor to be attached or removed each time adjustment is made. purpose.

[Means to solve the problem]

The color balance adjustment device for a color monitor according to the present invention includes three sensors that are attached to a location other than the image display area on the screen of the color monitor and detect the brightness of each color through filters of different colors; a detection circuit that detects the brightness of each color from the output of the sensor while changing the scanning range of the color monitor so as to match the mounting location or the corner of the image display area and inputting the same signal to each color signal circuit of the color monitor; The color monitor includes a memory that stores the detection value of the detection circuit in the initial state of the color monitor, and a color adjustment circuit that controls the operation of each color signal circuit of the color monitor based on the stored value of the memory and the output of the detection circuit.

[Effect]

According to the color balance adjustment device according to the present invention, although the sensor is fixed on the screen, the sensor does not interfere with the displayed image during normal image display, and the emitted light from the screen is incident on the sensor during color balance adjustment. can be done. Therefore, there is no need to attach or remove the sensor each time an adjustment is made, and measurements are taken at the same location on the screen.
Highly accurate measurement is possible with no variation in measured values. In general, accurate color balance can be achieved with a simple configuration by adjusting the level of each color signal circuit system based on the difference between the current measured value of brightness for each color and the stored value of the measured value in the initial state of the color monitor. You can also adjust the brightness.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color balance adjustment device for a color monitor according to the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a color monitor according to this embodiment. An escutcheon (frame) 12 is attached to the surface of the cathode ray tube 10, and both sides are defined by an inner edge 4 of the escutcheon (frame) 12. In addition, for plate making simulation,
The aspect ratio of the screen is often 1°1. cathode ray tube 10
Three optical sensors 16 are mounted on the lower side of the escutcheon 12 with their light-receiving surfaces facing the cathode ray tube 10 side. It is preferable that the three sensors 6 be located in positions hidden by the escutcheon 12 and as close to the center of the screen as possible. As may not be shown in the diagram, the light receiving surfaces of the three sensors 6 are colored green (G) and blue (B), respectively.
, a color filter that passes red (R) color component light is attached.

As a result, the three sensors 16 are G, BR, respectively.
It is possible to detect the color component light, and determine the brightness based on the detected value and the color balance based on the difference between them.

Here, normally, the cathode ray underscans so that its scanning range matches the screen range defined by the inner edge 14 of the escutcheon 12, so when detecting the color balance, the deflection angle is slightly increased. - Overscan so that the scanning range includes the mounting location of the sensor 16, as shown by the dotted chain line 18.

Note that in this case, since the amplitude of deflection is widened, the brightness on the screen decreases, so it is necessary to make adjustments taking this decrease into account.

Changing the scanning range is not limited to overscanning, but can also be done by varying the deflection centering current and shifting the normal rask position 22 to a position 24 that includes the mounting location of the sensor 16, as shown by the dashed line in FIG. Good too.

Furthermore, as shown in Figure 3, the signal of one scanning line is divided into an image display area and a color balance adjustment area except for the retrace period, and normally the signal is placed on the image display area and no signal is placed on the adjustment area. When adjusting the color balance, conversely, a test signal indicating the black level and white level may be placed in the pr, +◇fi area, and the image display area may be left with no signal. In addition, sensor 1
6 is attached at a position corresponding to this color balance adjustment area. Here, although it is not necessary to make the adjustment area non-signal during normal times, it is necessary to make the image display area non-signal during color balance adjustment. This is because when a signal waveform is placed on the image display area, when adjusting the level, especially when adjusting the black level, the light emitted by this signal waveform is repeatedly reflected on the glass surface of the cathode ray tube 10, reaches the sensor 16, and is detected. This is because

In this way, when displaying a normal image, the sensor 16
or does not interfere with the displayed image. Therefore, the sensor 16 can be fixed on the screen at all times, so there is no need to attach or remove it each time adjustments are made, and since the brightness and color balance are measured at the same location on the screen, there is no variation in the measured values. Accuracy can be measured.

FIG. 4 is a circuit diagram of this embodiment. G.B.

R three color signal input terminals 40g, 40b.

40r is a three-man powered selector 42g, 42b.

42r. selector 42g,
A black level signal and a white level signal for color balance detection are supplied from a control signal generation circuit 58 to the second and third input terminals of 42b and 42r.

Selectors 42g, 42b, and 42r are control signal generation circuit 5
It is switched by the black level signal from 8.

The outputs of the selectors 42g, 42b, 42r are j-segmentators 44g, 44b as white level adjusters.

44r. G signal circuit system white level adjuster 4
4g, the gains of the white level adjuster 44b of the B signal circuit system and the white level adjuster 44r of the R signal circuit system are the white (G) level adjustment signal from the control signal generation circuit 58, the white (B) 1 novel adjustment signal, Controlled by a white (R) level adjustment signal.

The outputs of the white level adjusters 44g, 44b, and 44r are respectively supplied to the first input terminals of adders 48g, 48b, and 48r as black level (pedestal level) adjusters. G
Signal circuit system black level adjuster 48g, B signal circuit system black level adjuster 48b, R signal circuit system black level adjuster 4
The black (
G) Level adjustment signal, black (B) Level adjustment signal, black (R
) A level adjustment signal f1 is supplied, and the pedestal levels of the G signal, B signal, and R signal are controlled by a control signal generation circuit 58.

The outputs of the black level adjusters 48g, 48b, 48r are the DC regeneration circuits 52g, 52b, 52r, and the inverted JJ3 width amplifier 54g.
, 54b, and 54r to the cathode ray tube 10.

The luminance signals B and G measured by the sensor 16 attached to the surface of the cathode ray tube] 0 are supplied to the comparator 56a,
Luminance signal G.

R is provided to comparator 56b. Comparator 56a.

56b compares the power of both people to find a difference, and the difference signal is supplied to the control signal generation circuit 58. Further, the output of the sensor 16 is supplied to the latch circuit 64, and the comparison circuit 66
is supplied to the first input terminal of.

A second input terminal of the comparator circuit 66 is supplied with the 0 output of the latch circuit 64 . Comparator circuit 66 thus compares the contents of latch circuit 64 and the output of sensor 16. The output of comparison circuit 66 is supplied to control signal generation circuit 58.

A color balance adjustment switch 60 is also connected to the control signal generation amount yb 58 .

FIG. 5 is a diagram showing details of the latch circuit 64 and comparison circuit 66. Among the outputs of the sensor 16, G.

A signal indicating the black level of B and R is a latch 64a.

64b and 64c, and the comparator 66a
, 66b, 66c and are compared with the latch signals. G,B,
The signal indicating the own level of R is sent to the latches 64d, 64e, 64.
f and comparators 66d, 66e, 6
It is compared with the latch signal at 6f. Next, the operation of this embodiment will be explained.

In this embodiment, the color balance is adjusted when the color monitor is first used, the brightness of each color component at that time is memorized, and the brightness of each color component is compared with the stored value later during use. The gain of the white level adjuster for each color signal system is adjusted so that the brightness of each color component always matches the initial value.
This can be done by foot-hacking the pedestal level of the black level adjuster 1. In addition, the color balance adjustment in the initial state can be detected by the difference in detected brightness of each color component of the optical sensor when the same test signal (black level signal and white level signal) is manually applied to each color signal system. This can be done by feedback controlling the gain of the white level adjuster and the pedestal level of the black level adjuster so that the difference in brightness between the two is equal to each other. Here, when combining three luminances, one color: green (G)
Based on the brightness of other colors: blue (B) and red (R),
It matches the brightness of

When the adjustment switch low is turned on after the color monitor is installed, the black level is first adjusted, and then the own level is adjusted. This is because the black level is adjusted by subtracting the pedestal level, so even if you adjust the white level first, if you adjust the black level afterwards, the own level will shift by the amount that the pedestal level increases or decreases. be.

When adjusting the black level, the control signal generation circuit 58 switches the black/2 white switching signal to the black side and selects the selector 42g42b.
42r is connected to the second input terminal side, and a black level signal is generated in synchronization with the retrace period. As a result, G
A common black level signal is input to the , B, and R signal circuit systems. Here, if the value of the black level signal is the black level itself, the cathode ray tube 10 does not emit any light and the optical sensor 1
Since the output of No. 6 also becomes 0 and only feedback control is possible, the signal has a value such that a luminance of several percent, for example, about 5% of the white level is obtained as the black level.

When the adjustment switch 60 is turned on, the control signal generation circuit 5
8 supplies a rask control signal to the cathode ray tube 1o, varies the scanning range of the cathode ray by any of the methods shown in FIGS. , the brightness of the cathode ray tube 10 that emits light based on the white level signal is measured by a sensor]6. [sensor] 6 is the moon on the surface of the cathode ray tube 10 that emits light based on the black level signal (in degrees for each of the three color components of G, B, and R)
3d]. "The comparators 56a and 56b are C**** +
The difference B-G between
Enter 8.

The Fli control signal generation circuit 58 generates the difference/7) signal B-G.
Generates a black (B) level 1 adjustment signal and a black (R) level adjustment signal proportional to RG, and a black level 1 adjustment signal 48 b4;
At 8 r, the black level of the B and R signal circuits is 1. Add it to No. 2 to adjust the black level of the B and R signal circuits. For example, when the B luminance is higher than the prefectural standard G luminance,
A positive black (B) level adjustment signal is generated according to the difference signal, and the pedestal level of the B signal circuit system is increased by j. Here, the control signal generation circuit 58 supplies a constant black (G) level adjustment signal to the black level adjuster 48g.

In this way, by increasing the signal level during the retrace period, the signal level in the image display area is phantomly lowered, and the brightness of the image becomes darker by that amount. On the contrary, B<
When the signal is G, a black (B) level iJ,',1 signal of negative polarity is generated. Figure 6 shows black level adjustment 11,? ] 4 Each signal waveform is shown.

The control signal generation circuit 58 repeats this operation every retrace period, and when the difference signal becomes sufficiently small, it latches this data and thereafter adjusts the levels of the black (B) level adjustment signal and the black (R) level adjustment signal. to be fixed.

Next, white level adjustment is performed, and as in the case of black level adjustment, the control signal generation circuit 58 generates a white level signal in synchronization with the retrace period, and also sets the black/white switching signal to the white side. , selector 42g.

42b and 42r are connected to the third input terminal side, and G.

A common white level signal is input to the B and R signal circuit systems, and the sensor 16 calculates the white level luminance for each color.

The control signal generation circuit 58 generates a white (B) level adjustment signal and a white (R) level adjustment signal that are inversely proportional to the difference signals BG and RG, and outputs a white (R) level adjustment signal to the own level adjuster 44b.

Adjust the gain of 44r. For example, when B>G, white (
B) The level adjustment signal decreases and the gain of the B signal circuit system decreases, so the brightness becomes darker. On the other hand, when using 5 BAG, the white (B) level adjustment signal is grounded, the gain is increased, and the brightness is brightened. Again, the control signal generation circuit 58 supplies a constant white (G) level adjustment signal to the white level adjuster 44g.

This is repeated every retrace period, and when the difference signal becomes sufficiently small, this data is latched, and thereafter the levels of the white (B) level adjustment signal and the white (R) level adjustment signal are fixed.

Note that the black level was adjusted to a brightness level of about 5%, so if you change the gain to adjust the white level, the black level will also fade, so you need to adjust the black level and white level as described above 3 to 4 times. Repeat to complete color balance adjustment.

Next, the reference values of the black and white level signals for each color dynamic circuit system after color balance adjustment are stored. Therefore, the gj control signal generation circuit 58 switches the black/white switching signal to the output side again, connects the selectors 42g and 42b42r to the second input terminal side, and generates a black level signal in synchronization with the blanking period. G.

A common black level signal is input to the B and R signal circuit systems, and the outputs of the sensor 16 at 1 are set as the black (G) level, black (B) level, and black (R) level, respectively, and the latch 64a,
64b and 64c.

Next, similarly, the control signal generation circuit 58 switches the black/white switching signal to the white side, connects the selectors 42g42b, 42r to the first input terminal side, and selects G.

A common white level signal is input to the B and R signal circuit systems, and the output of the sensor 16 at this time is set to the white (G) level and white (
B) level, as the white (R) level, latch 64cl,
Latch to 64e and 64f. This completes the initial setting of the color monitor.

If it is necessary to adjust the color balance during actual use, the adjustment switch 60 is turned on. Thereby, the control signal generation circuit 58 compares the black and white levels of each color component with the reference value. First, the control signal generation circuit 58
Switch the white switching signal to the output side and selectors 42g and 42b.
, 42r are connected to the second input terminal side, a black level signal is generated in synchronization with the blanking period, and a common black level signal is manually input to the G, B, and R signal circuit systems. 16 outputs respectively black (G) level and black (B)
Level, black (R) level, latches 64a, 64b
, 64c and the comparator 66a.

Compare with 66b and 66c. The control signal generation circuit 58 generates a black (G) 1 novel trimming signal, a black (B) level adjustment signal, and a black (R) level adjustment signal according to the comparison results, and controls the black level adjusters 48g and 48b.

48r, it is added to the black level signals of the G, B, and R signal circuit systems to adjust the black levels of the G, B, and R signal circuit systems. For example, whether the latch data is higher than the sensor output ■
, r generates a black level adjustment signal of m polarity corresponding to the difference, and increases the pedestal level. As a result, the black level of each color signal system coincides with the initial state in which the color balance has been matched, and changes over time in color balance and brightness are compensated for.

Next, similarly, the control signal generation circuit 58 switches the black/white switching signal to the white side and selects the selector 42g.

42b and 42r are connected to the first input terminal side, and GB and R
A common white level signal is input to the signal circuit system, and the outputs of the sensor 16 at this time are set as white (G), white (B) level, and white (R) level, respectively, and the latches 64d, 64e, and '64f data and comparators 66d, 6
Compare 6e and 66f. The control signal generation circuit 58 generates a white (G) level adjustment signal, a white (B) level adjustment signal, and a white (R) level adjustment signal according to the comparison results, and the white level adjusters 44g, 44b, and 44r output a white (G) level adjustment signal, a white (B) level adjustment signal, and a white (R) level adjustment signal. , adjust the gain of the R signal circuit system.

As a result, the black level and white level of each color component match the initial state level of the color monitor, and changes over time in color balance and brightness are compensated for.

As described above, according to this embodiment, the black level and white level of each color signal circuit system are adjusted so that the luminances of the three primary colors are equal to each other, so that color balance is achieved. After adjusting the color balance, the black level and white level of each color component circuit system are feedback-controlled according to the comparison result between the level for each color component and the level when the color balance is matched. Color balance and brightness changes over time are compensated for. In addition, the sensor 16 is fixed on the surface of the cathode ray tube 09 at a position that does not obstruct the normal image display, and the scanning range is variable so that the mounting location of the sensor 16 is included in the scanning range when the color balance is adjusted. Therefore, the luminance of the three primary colors can always be measured at the same location, resulting in high measurement accuracy. Also, by pressing the switch 60,
Since the color balance is adjusted within a short time, if the switch 60 is linked to the power switch, the color can be adjusted to the color when the power is turned on, and it is possible to prevent continued use without noticing deterioration.

Note that this invention is not limited to the embodiments described above, and can be modified in various ways. For example, the brightness of each color component may be measured separately using three sensors, or one optical sensor may be used and the B, G, and R filters may be replaced each time the brightness of each color is measured. . Further, the number of color components may be three or more, and G may not be used as a reference for relative comparison.

〔Effect of the invention〕

As explained above, according to the color balance adjustment device according to the present invention, although the sensor is fixed on the 1ilj surface, the sensor does not interfere with the displayed image during normal image display, and when adjusting the color balance, the sensor does not interfere with the displayed image. The light emitted from the screen can be incident on the sensor. Therefore,
There is no need to attach or detach the sensor each time an adjustment is made, and /11 is set at the same location on the screen, so highly accurate measurements are possible without variations in measurement values. Furthermore, based on the comparison result between the brightness A1 value for each color and the stored value in the initial state, the self-level and black level of the C-3 color signal circuit system can be adjusted to achieve accurate coloring with a simple configuration. balance,
Brightness can be adjusted.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the arrangement of optical sensors in an embodiment of the color balance adjustment device according to the present invention, FIG.
Fig. 3 is a diagram showing a modification of the sensor arrangement, Fig. 4 is a circuit diagram of this embodiment, Fig. 5 is a diagram showing details of the latch circuit and comparison circuit, and Fig. 6 is a signal when adjusting the black level. It is a figure which shows a waveform. ]6...Optical sensor, 44g, 44b44
r-=white level adjuster, 48g, 48b2] 8 black level adjuster, 58... rl; j control signal generation port path, 64... latch circuit, 6... ratio φ alternating circuit.

Claims (1)

[Claims] Three sensors are attached to a location other than the image display area on the screen of a color monitor and each detects the brightness of each color through a filter of a different color, and the mounting location of the sensor is within the image display area. means for detecting the brightness of each color from the output of the sensor while changing the scanning range of the color monitor and inputting the same signal to each color signal circuit of the color monitor; A color balance adjustment device for a color monitor, comprising means for storing a detected value, and color adjustment means for controlling the operation of each color signal circuit of the color monitor based on the stored value in the storage means and the output of the detection means.