JPH0241981Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a color image monitor white balance adjustment device for adjusting the white balance of a color image monitor that displays a color image signal such as a color television signal and monitors its image quality. In particular, with a configuration that is simple enough to be easily incorporated into a monitor device, it is possible to perform high-precision white balance adjustment in a relatively short time with good reproducibility without requiring special skill, preferably automatically. It has been made possible to do so.

[Prior Art] In general, color image monitors monitor the image quality of color image signals, and in particular monitor the image quality of color television signals produced in television studios, broadcast vans, etc. when producing color television broadcast programs. It is used to determine the quality of images and plays an important role in maintaining good color image quality. However, adjusting the white balance, which is a prerequisite for determining color image quality, has conventionally required special skill, and even experts have difficulty adjusting it due to the surrounding conditions such as the type of lighting, the color of surrounding objects, etc. It has been considered extremely difficult to make adjustments with good reproducibility due to the influence of white balance, and there has been a demand for a device that can make white balance adjustments with good reproducibility through simple operations without requiring special skill. It had been.

Particularly from the perspective of production of color television broadcast programs, it is possible to quickly perform high-precision white balance adjustment with good reproducibility without any manual effort.
In addition, there has always been a desire to realize a color image monitor white balance adjustment device that has a simple configuration, is low cost, and does not require equipment costs even when installed in large numbers.
Furthermore, by automating the device, it is possible to eliminate human labor and maintain reproducibility by immediately responding to changes over time, aging, and changes in ambient conditions, even if it takes some time to make manual adjustments. Overall it is advantageous.

Therefore, white balance adjustment is performed by additive color mixing so that achromatic images of white, black, and gray with intermediate brightness can be displayed at a predetermined color temperature on a color image display cathode ray tube, that is, a color display tube. The balance between the primary color signals that display a colored image is adjusted over a wide range of signal levels, and there are two types of adjustment: simultaneous adjustment in which each primary color is adjusted in parallel, and sequential adjustment in which each primary color is adjusted in series.

The advantages and disadvantages of such simultaneous white balance adjustment and sequential adjustment will be compared. First, a control loop that performs feedback control of the operating state of each primary color in the color display tube so that the luminance of each primary color in the color display tube is balanced and an achromatic display is obtained through additive color mixing is established. Since three systems are required for each primary color, the circuit configuration and adjustment procedure are complicated and expensive. On the other hand, since the adjustment for each primary color can be processed in parallel at the same time, there is an advantage that the adjustment can be made faster in principle. On the other hand, in sequential adjustment, one system is switched and used for each of the three primary colors, which has the advantage of simplifying the circuit configuration and adjustment procedure and reducing the cost. However, since the adjustment for each primary color is processed in chronological order, it has the disadvantage that it takes time in principle.

Furthermore, in simultaneous adjustment, deviations in the component characteristics themselves and their aging changes between the three control loops significantly affect the adjustment results, and the adjustment itself becomes complicated and difficult. This has the advantage that the effects of changes in the primary colors are balanced and reduced among the primary colors. On the other hand, sequential adjustment has the advantage that the effects of changes in the characteristics of the control loop components are balanced and reduced between each primary color, but the effects of changes in external conditions differ for each primary color. However, there are other drawbacks such as lack of reproducibility and stability of the adjustment.

The above-mentioned advantages and disadvantages of simultaneous adjustment and sequential adjustment of white balance are balanced against each other, and there are advantages and disadvantages, but there are decisive advantages and disadvantages between the two as follows, and the disadvantages of simultaneous adjustment are compensated for. It is recognized that it is difficult.

In other words, when simultaneously adjusting the white balance,
Achromatic color display by additive mixing of three primary color emissions is achieved by parallel processing of three systems of adjustment for each primary color light component separated through each primary color filter, as described later in the conventional device. The overlap between the spread of the normal band and the spread of the normal band of each primary color filter causes a mix-up in the photoelectric conversion output of each primary color that is difficult to correct. Since unavoidable mixing occurs due to internal reflection, there is a limit to the accuracy of skin balance adjustment. In addition,
Since there are variations in the characteristics of each primary color filter and their changes over time, there are limits to the stability and reproducibility of the adjustment results.

On the other hand, in the sequential adjustment of the white balance, since the color display tube emits monochrome light for each primary color, the above-mentioned mixing of photoelectric conversion outputs between the primary colors does not occur in principle. Furthermore, since the display light emitted from the color display tube is directly received by the photoelectric conversion element, there is no possibility of instability caused by a filter, and highly accurate adjustment can be expected.

On the other hand, as a conventional white balance adjustment device that meets the above-mentioned demands in the production of color television broadcast programs, there is, for example, a "white balance adjustment device" described in Japanese Utility Model Publication No. 57-34853. This conventional apparatus is configured to perform the above-mentioned simultaneous adjustment for the purpose of speeding up white balance with good reproducibility. That is, the display luminescence of the color display tube is separated by three primary color filters, each primary color luminescence component is detected, and the drive voltage and screen voltage of the color display tube are adjusted so that the detection output for each primary color becomes a predetermined value. is configured to do so.

Therefore, although the three primary colors can be adjusted simultaneously, when the display light emission is analyzed through each primary color filter, the photoelectric conversion output of each primary color is mixed with other primary color components and is affected by this. Furthermore, the effect of this effect is that different types of color display tubes have different emission spectrum characteristics, so even if the photoelectric conversion output voltage value is the same, the light emission may vary depending on the type of color display tube or individual color display tubes. It may occur that the shades of the colors differ significantly.

In order to avoid a decrease in the accuracy of measurement adjustment due to such color mixture, a matrix circuit in the data storage section reverses the polarity of the other primary color components mixed in and adds them to the photoelectric conversion output of the measured color, thereby canceling out and removing the mixed components. A circuit configuration is adopted. However, since it is necessary to cancel and remove such mixed components for each primary color and the other two primary colors, it must be repeated at least six times, and furthermore, the degree of mixing of other primary color components depends on the photoelectric conversion output level. However, the process is extremely complicated, and the accuracy of adjustment cannot be obtained.

Furthermore, even once an adjustment is made, the adjusted state cannot be applied to other color display tubes, and readjustment is required. Moreover, it has various drawbacks, such as a complicated circuit configuration and high cost.

[Purpose of the invention] Therefore, the purpose of the invention is to eliminate the simultaneous adjustment type white balance adjustment, which has many drawbacks including the essential drawbacks as described above, and adopt a sequential adjustment type white balance adjustment, and to Eliminates the relatively minor drawbacks that conventional sequential white balance adjustment had, and allows high-precision white balance adjustment with good reproducibility and no skill required using a simple circuit configuration. An object of the present invention is to provide a color image monitor white balance adjustment device that can adjust the white balance in a relatively short time.

[Key Points of the Invention] That is, the color image monitor white balance adjustment device of the present invention adjusts the standard for each primary color in a color image monitor equipped with a color display tube and signal level adjustment means and amplification means for each primary color for input image signals. an adjustment signal source that generates an input image signal;
A photoelectric conversion element that receives light emitted from a display image of a color display tube, a memory means that stores a reference voltage corresponding to the reference light emission of the color display tube, and a converted output voltage of the photoelectric conversion element and a reference voltage read from the memory means. and a comparator that corresponds to the display image of the color display tube when reference input image signals of at least high signal level and low signal level are sequentially supplied for each primary color from the adjustment signal source. Using the comparative output voltage, the signal level adjusting means is feedback-controlled for each primary color for high signal levels, and the control means for feedback-controlling the clamp potential of the amplifying means for each primary color for low signal levels. The present invention is characterized in that the control means sequentially adjusts the white balance of the color display tube.

First, as the gist of the present invention, the main points of improvements made to eliminate the drawbacks that the sequential white balance adjustment had in the past will be explained.

The main drawback of conventional white balance adjustment using the sequential adjustment method is that since adjustments are made for each primary color in a time-series manner, the influence of external conditions differs for each primary color, and it is also affected by changes over time. The situation lies in the fact that uncertainty and instability become significant. In particular, the influence of ambient light contamination on display luminance detection results is such that even if the light-receiving surface of the detection light-receiving element is brought into close contact with the display surface of the color display tube, external light incident on other parts of the face plate may Considering that it propagates and gets mixed in due to reflection on the inner surface of the face plate, its influence is difficult to avoid.
The variation in the degree of influence between each primary color significantly reduced the stability and reliability of the measurement results, especially at low levels of display light emission.

In the present invention, as a countermeasure against such a decrease in stability and reliability in white balance adjustment results, we have developed a system in which external light incident on the display surface of the color display tube is placed near the main photoelectric conversion element that receives the display light emitted from the color display tube. Auxiliary sub-photoelectric conversion elements that actively receive light are provided, and the conversion outputs of these main and sub-photoelectric conversion elements are added to have opposite polarities to offset and eliminate the influence of ambient light. That is, the light-receiving sensitivity of the sub-photoelectric conversion element is adjusted by, for example, placing a density filter in front of it so that the output of the above-mentioned addition becomes approximately zero when no light is emitted from the color display tube.

Furthermore, as another countermeasure for reducing the stability and reliability of the white balance adjustment results described above, in the present invention, when a monochrome image signal as an adjustment reference is supplied to the color image monitor to be adjusted, the reference color temperature is In order to obtain white display light emission, initial adjustment is made by adjusting the drive circuit for each primary color of the color display tube, and the initial adjustment data is stored in the reference memory device, and subsequent adjustment for each primary color is performed. The operating conditions of the drive circuit for each primary color are feedback-controlled in accordance with the result of comparing the display luminescence measurement data with the initial adjustment data.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the basic configuration of a color image monitor white balance adjustment device improved according to the present invention as described above.

In the configuration shown in FIG. 1, 1 is a calibration signal source, 2
R, 2G, 2B are red, green, and blue system attenuators, 3
R, 3G, 3B are red, green, blue system clamp potential control amplifiers, 4 is a color display tube, 5R, 5G, 5
B is an adjustment control section for red, green, and blue systems. 6H and 6L are holding memories for high signal level H and low signal level L, respectively, 7H and 7L are reference memories for H and L, respectively, 8H and 8L
are comparators for H and L, respectively, and these parts constitute adjustment control sections 5R, 5G, and 5B. In addition, in FIG. 1, the details of only the red system adjustment control section 5R are shown for the sake of simplicity.

Reference numeral 9 denotes an optical sensor probe that can be fixedly attached to the face plate of the color display tube with, for example, a rubber suction cup, and includes a main photoelectric conversion element 10M, a main amplifier 11M for amplifying its photoelectric conversion output, and a sub-photoelectric conversion element 10S. and a sub-amplifier 11S that amplifies the photoelectric conversion output thereof, a trimmer resistor 12 that adjusts the output level of the sub-amplifier 11S, and a subtracter 13 that subtracts the output of the trimmer resistor 12 from the output of the main amplifier 11M.

14-1 and 14-2 are interlocked with each other, and are respectively a memory setting position A for setting the reference memories 7H and 7L, a normal monitor operation position B for receiving a monitor color video signal,
This is a mode changeover switch that has a test position C for white balance adjustment. 15-1~15
-4 are H/L and R/L which selectively switch each R, G, B system and switch between high signal level H and low signal level L in each system in conjunction with each other.
This is a G/B selection manual selector switch.

16 is an initial setting circuit that selects all of the attenuators 2R, 2G, and 2B. Switch 17-RH,
17-GH, 17-BH and 17-RL, 17-
GL and 17-BL are attenuators 2R and 2, respectively.
G, 2B attenuators and amplifiers 3R, 3G, 3
This is a switch for initially setting each amplification gain of B, and each position A indicates normal white balance adjustment, and each position B indicates an initial setting mode. 18-RH, 18-GH, 18-BH
and 18-RL, 18-GL, 18-BL are switches 17-RH, 17-GH, 17-BH, respectively.
and variable resistors for initial setting value input connected to 17-RL, 17-GL, and 17-BL.

The initial setting of the reference memories 7H and 7L is performed for the color display tube 4 of the actual monitor. To do this, first, switch 14-1 to position A, turn on switch 16, and then turn switch 14-1 to position A.
7-RL, 17-GL, 17-BL and 17-
Switch RH, 17-GH, 17-BH to position B, variable resistors 18-RH, 18-GH, 18-
Initial settings from BH, 18-RL, 18-GL, and 18-BL are supplied to attenuators 2R, 2G, 2B and amplifiers 3R, 3G, and 3B.

In addition, here, variable resistors 18-RL, 18-
GL, 18-BL, 18-RH, 18-GH, 18
−BH shall be set in advance according to the standard white color temperature of 9300°K.

In addition to the above-described position settings of each switch, when the optical sensor probe 9 is placed at a predetermined position on the screen of the color display tube 4, for example, when the screen is divided into two areas: a bright area corresponding to the high level H and a dark area corresponding to the low level L. , fixedly attached to one of the parts. Next, the black and white image signal, which is used as a reference for initial setting, is transferred from the switch 14-1 to the attenuator 2.
In addition to supplying all of R, 2G, and 2B, the three primary color reference signals taken out from the optical sensor probe 9 are supplied to one of the R, G, and B primary color systems selected by manual selection of the changeover switch 15-3. The R, G, B outputs of the H, L channels of each R, G, B channel at that time are supplied to the H level part or L level reference memory 7H or 7L and taken out in open loop form as the reference. Write to memory 7H and 7L sequentially and write to reference memory 7.
Finish setting H and 7L. At this time, in the optical sensor probe 9, the influence of external light is canceled out by the two photoelectric conversion elements 10M and 10S, and no output from the subtracter 13 appears.

More specifically, the display light emitted from the display surface of the color display tube 4 is received by the main photoelectric conversion element 10M made of, for example, a photodiode, and the converted output is supplied to the subtracter 13 via the main amplifier 11M, and the display Ambient light incident on the surface is passed through a density filter F if necessary, and the converted output of the received sub-photoelectric conversion element 10S is supplied to a subtracter 13 via a sub-amplifier 11S and a subtracter 12 in sequence.

The difference output of the subtractor 13 should be obtained by canceling and removing the ambient light conversion output component mixed into the display light emission conversion output, so the difference output should be zero when the display light emission is stopped. , concentration filter F of the sub-photoelectric conversion element 10S, sub-amplifier 11
Adjust the response of either S or attenuator 12.

The difference output signal is sequentially supplied to one of the adjustment control sections 5R, 5G, and 5B for each primary color via the changeover switches 14-2 and 15-3. These adjustment control units 5R, 5G, and 5B all switch the positions of high signal level H and low signal level L for each primary color R, G, and B, as shown in the figure only for the configuration of red R. switch 15-3
The differential output signal from the subtracter 13 is selectively supplied to the reference memories 7H and 7L for high signal level H and low signal level L, and is stored therein.

As described above, the converted output signal when the reference monochrome image signal for initial adjustment is used as an input signal is stored in the reference memories 7H and 7L as the initial value to be used as a reference in subsequent signal processing. , the initial settings will be remembered until updated.

Next, we will discuss white balance adjustment.

Set the changeover switches 14-1 and 14-2 to calibration position C, and send the high signal level H and low signal level L calibration signals for each primary color from the calibration signal source 1 to one of the attenuators 2R, 2G, and 2B. At the same time, the output from the optical sensor probe 9 is supplied to the mode selector switch 15-3 side. Furthermore, switch 16 is opened and switch 1 is opened.
7-RL, 17-GL, 17-BL, 17-RH, 1
7-GH and 17-BH are switched to position A for forming a closed loop.

The mode selector switch 15-1 selects which output signal of the R, G, or B system and H or L level is to be extracted from the calibration signal source 1, and the switch 15-2 selects the output signal of the R, G, or B system.
-1, a calibration signal is supplied to the selected attenuator 2R, 2G, 2B for subsequent adjustment for each primary color.

When adjusting each primary color, please set the high signal level H.
The output from the optical sensor probe 9 is held in the holding memory 6H or 6L for low signal level L, and the conversion output read from the holding memory 6H or 6L and the reference value read from the reference memory 7H or 7L. are supplied to a comparator 8H or 8L for high signal level H and low signal level L to compare the selected level of the selected system.

Among the comparison outputs of the above-mentioned comparators in the adjustment control units 5R, 5G.5B for each primary color, the high signal level H
The comparison output of comparator 8H for each primary color is attenuator 2 for each primary color.
R, 2G, and 2B respectively to feedback control the degree of subtraction, and also supply the comparison output of the comparator 8L for low signal level L to the amplifiers 3R and 3 for each primary color.
G and 3B respectively to control the clamp potential of each amplifier.

The selection of the attenuators 2R, 2G, and 2B for each primary color in accordance with the sequential adjustment of the white balance is performed by a changeover switch 15-2 that operates in conjunction with changeover switches 15-1 and 15-3 that perform similar selections. Control.

After completing the adjustment of each system of R, G, and B through the above white balance adjustment,
The adjustment values for each are held in the holding memories 6H and 6L, respectively, and the attenuators 2R and 2R are adjusted accordingly.
2G, 2B attenuation and amplifiers 3R, 3G,
The clamp potential of each of the 3B amplifiers will be held at a respective calibrated level. In this state, by switching the switch 14-1 to the normal monitor operation position B and removing the optical sensor probe 9 from the screen of the color display tube 4, the color video signal can be converted to each of R, G, and B. Drive circuit 2R, 3
R, 2G, 3G, 2B, and 3B, and a color monitor image is displayed on the color display tube 4 to be displayed on the monitor.

The color image monitor white balance adjustment device of the present invention with the above-mentioned basic configuration receives the display light emitted from the color display tube, photoelectrically converts it, and returns it to the color display tube drive circuits 2R, 3R, 2G, 3G, 2B, and 3B. Only one control loop is provided for each primary color, and the main photoelectric conversion element 10M directly receives the display light without using any primary color filter. Therefore, the configuration of the adjustment control circuits 5R, 5G, and 5B for each primary color for white balance adjustment is as follows.
This is much simpler and clearer than conventional devices that adjust the three primary colors simultaneously, and the adjustment itself is extremely simple and easy.

In the present invention, since such a single adjustment control system is used by sequentially switching over the reference input signal for each primary color in chronological order, the required adjustment time is theoretically longer than that of the simultaneous adjustment method. However, in particular, if it is automated based on the setting of an appropriate sequence as will be described later, the required adjustment time will not be long in practice, and it will be fully compatible with the work of producing broadcast programs.

Moreover, according to the present invention, there is no mixing of other primary color components that emit light at the same time as in the simultaneous adjustment type, making it possible to adjust the white balance with high precision.
Furthermore, by separately providing the external light receiving element 10S, the influence of external light can also be canceled out. In addition, in the present invention, the reference adjustment states for high-brightness light emission and low-brightness light emission are initially set, and the reference memory 7H,
7L, and subsequent changes in characteristics can be adjusted, making it possible to stably maintain a good adjusted state with good reproducibility.

Moreover, in addition to interposing a γ correction circuit for each primary color in the input image signal supply connection line, it also separately corrects deviations in white balance adjustment that occur in the medium brightness region due to cancellation between each primary color of the γ characteristics of the color display tube. By storing the information and controlling the γ correction circuit according to the input image signal level, a good white balance adjustment state can be obtained over a wide range of input image signal levels.

FIG. 2 shows an example of a specific configuration in which the essential parts of the basic configuration shown in FIG. 1 of the white balance adjusting device of the present invention are digitized and the above-mentioned γ correction is also improved.

In FIG. 2, as in the basic configuration shown in FIG. 1, a switch is used to switch between the luminance signal source 20Y that supplies the black and white image signal for initial setting and the calibration signal source 1 that supplies luminance signals of multi-level signal levels. 14
-1 and supplies it to the matrix circuit 21. The matrix circuit 21 uses the switching output as the reference color difference signal R- from the chromaticity signal source 20C.
The primary color signals R, G, and B are mixed with Y and B-Y to form primary color signals R, G, and B at each stage of signal level. These primary color signals R, G, B are converted into γ correction circuits 31R, 31 for each primary color.
G, 31B, attenuators 2R, 2 for each primary color, as in the basic configuration shown in the first diagram.
G, 2B and amplifiers 3R, 3G, 3B are sequentially supplied to adjust the signal level necessary for white balance adjustment. The adjusted output is supplied to the color display tube 4.

Sequential display light emitted for each primary color in the color display tube 4 is sequentially received by a photoelectric conversion element 10M similar to that in the basic configuration shown in the first figure. The peak hold circuit 26 outputs the sequential photoelectric conversion outputs.
The signal is supplied to the A-D converter 27 via the A/D converter 27, where it is digitized. The digital photoelectric conversion outputs from the A-D converter 27 corresponding to the reference input signals of each primary color, for example, wide range, middle range, and low range signal levels, are supplied to the average value circuit 28, and the respective digital Find the average value. Therefore, the digital average photoelectric conversion output values corresponding to the reference input signals of the wide range H, middle range M, and low range L signal levels for each of the primary colors R, G, and B obtained in this way are as follows.
It is then stored in the memory 29. The output read from the memory 29 is supplied to a comparator 30, where the result of comparison with a reference initial adjustment value stored in advance in the memory 29 is sent to a counter via a limiter 24 that limits the operating range of white balance adjustment. 23.

In the counter 23, the standard initial setting data corresponding to the standard input monochrome image signal described above is set as an initial value, and then comparison data corresponding to the standard input signal at each stage of the signal level for each primary color is calculated. Count up or count down. The digital value of the counting result is D-
After supplying it to the A converter 22 and converting it into analog,
The signal is supplied to the γ correction circuits 31R, 31G, and 31B for each primary color for feedback control. The counting results of the counter 23 are directly supplied to the attenuators 2R, 2G, and 2B for each primary color for feedback control, and are passed through the D-A converters 22R, 22G, and 22B to the amplifiers 3R, 3G for each primary color. , 3B to perform respective feedback control.

In FIG. 2, the sequential operations of the circuits described above in accordance with each primary color and each signal level are all performed under the control of a sequence set by a control unit 25.

The control unit 25 controls the operation of each circuit so as to set the sequence of sequential white balance adjustment according to the present invention and perform automatic adjustment.
Selects equipment startup, automatic/manual switching, setting of adjustment conditions during manual adjustment, etc.

Next, various flowcharts showing an example of the adjustment control process at each stage in the control unit 25 in the white balance adjustment apparatus of the present invention having the configuration shown in the second figure will be sequentially shown.

First, FIG. 3A shows a flowchart showing the process of performing manual white balance calibration in the apparatus of the present invention.

In the process shown in FIG. 3A, in step S1, the apparatus of the present invention and the monitor to be adjusted are activated and aged for 30 minutes or more. In the next step S2, the switch 25b is set to the manual position, and then the process proceeds to step S3, where the color display tube 4 to be adjusted is demagnetized. In the next step S4, a calibration signal for white balance adjustment is input to the apparatus of the present invention. Next, in step S5, the white balance is manually adjusted, and then the process proceeds to step S6, where the color monitor to be adjusted is adjusted.
The obtained white balance adjustment state is set, and then in step S7, the optical sensor probe 9 containing a built-in photoelectric conversion element is attached to the display surface of the color display tube 4. Next, in step S8, the amount of ambient light is reduced to 3 units or less, and then the process proceeds to step S9, where the automatic adjustment start switch 25a is pressed. Furthermore, step S10
At , writing of subsequent automatic adjustment data to the memory 29 is started.

Next, FIG. 3B shows a flowchart of the process of recalibrating the white balance for a color image monitor that has undergone white balance adjustment and a series of subsequent automatic white balance adjustments as described above.

In FIG. 3B, first, in step S11, the device of the present invention and the monitor to be adjusted are activated and aging is performed. In the next step S12, the switch 25b is set to the automatic adjustment position,
Next, the process proceeds to step S13, where the color display tube 4 to be adjusted is demagnetized. After that, step S1
The process proceeds to step S4, where the color monitor to be adjusted is set to the standard operating condition, and the process further proceeds to step S15. Here, the optical sensor probe 9 is attached to the display surface of the color display tube 4. Next, in step S16, the amount of ambient light is reduced to 3 units or less.
In the next step S17, the automatic adjustment start switch 25a is pressed down, and then in step S18
Proceed to automatically readjust the white balance.

Next, a flowchart for manual adjustment of white balance is shown in FIG. 3C.

In the process shown in FIG. 3C, first, step S
21, a calibration signal is supplied to the color monitor to be adjusted, and the manual selector 25d is set to R-H,
G-H and B-H are set alternately to adjust the high signal level for each primary color using the manual up/down switch 25C so that the white color of the high-brightness display white part has the specified color temperature. Adjust the response. Next, the process proceeds to step S22, where the manual selector 25d is set to RL, GL, BL.
Manually set the
Similar adjustments are made using the down switch 25C. Furthermore, in step S23, the manual selector 25d is set alternately to RM, GM, and BM, and the manual up/down switch 25C is set so that the white color of the medium volatility display portion has a predetermined color temperature. Repeat the same adjustment. Thereafter, the process proceeds to step S24, where the white balance adjustment state of the displayed white screen is checked over the entire brightness region.

Next, white balance adjustment for each system of R, G, and B is performed at each stage of signal levels H, M, and L, and the white balance adjustment data is retained in memory as a setting value for future use of the color monitor. The flowchart is shown in Figure 4A.

In the process shown in FIG. 4A, in step S31, adjustment for canceling and eliminating ambient light reception output between the main and sub photoelectric conversion elements 10M and 10S in the optical sensor probe 9 attached to the color display tube 4 is displayed. Performed with zero brightness.

Then, the process proceeds to step S23, where the luminance signal is switched to the signal level of each level from the calibration signal source 1, and the operation of the chromaticity signal source 20C is stopped. In this state, in step S33, the primary colors R, G, and B are sequentially switched, and then the process proceeds to step S34, where the signal levels H, H, and B at each stage are changed.
All operating conditions are automatically and sequentially set by sequentially switching M and L, and then photoelectric conversion output is processed in step S35. In the next step S36, the data resulting from the processing is sequentially written into the memory 29. Next, step S3
7. After repeating and confirming the above signal processing in S38, the process proceeds to step S39, where the automatic white balance adjustment state is set, and the switch 14-1 is further switched to position A (C). The input color video signal is accepted, and the chromaticity on/off signal of the chromaticity signal source 20C is switched to the on position.

A flowchart of the process of automatically readjusting the white balance is shown in FIG. 4B.

In the process shown in FIG. 4B, after removing the influence of ambient light in step S41, only the luminance signal from the calibration signal source 1 is input in the next step S42. Next, step S
At step 43, all the operating conditions are sequentially set in the same way as described above, and after confirming the standard adjustment state, the automatic adjustment process begins, and the process moves to step S45 via step S44. Here, after setting the luminance signal to a high signal level H, the process proceeds to step S46, where signal processing of the photoelectric conversion output of display light emission is performed.

Next, the process proceeds to step S47, where the data resulting from the processing is compared with reference data in the memory 29. As a result of the comparison, if the measured data and the reference data are equal, a flag indicating good adjustment at high signal level is set in step S48. That is, if the measured value is smaller than the reference value, the white balance operating condition setting counter 23 is counted up in step S49, and if the measured value is larger, it is counted down in step S50.

After that, the process goes to step S51 and then to step S.
Step S52 sets the reference luminance signal to low signal level L, and then the process moves to step S53. Here, the signal processing of the photoelectric conversion output of the display light emission is performed again, and then, in steps S54 to S58, the same reference comparison as in the case of the high signal level H is performed on the data resulting from the processing.

Next, the same signal processing and data processing at each high and low signal level are performed in steps S59 to S65 for the reference luminance signal at the mid-range signal level, and then the process proceeds to step S66.

At this point, confirm that the adjustment has been completed under all operating conditions. Next, if necessary, repeat the entire process described above in step S67, and then proceed to step S67.
8, the process of maintaining the white balance adjustment state described above begins.

Next, a flowchart of the process of canceling and removing ambient light components within the optical sensor probe 9 is shown in FIG.

In the process shown in Figure 5, first, step S
At step 71, the color display tube 4 is turned off, and the sensitivity of the ambient light receiving sensor 10S is maximized. Next, steps S72 to S7
4, the ambient light sensor 10 is repeatedly activated until the photoelectric conversion output during no display becomes zero.
Adjust the sensitivity of S.

Next, the process proceeds to step S75, where it is confirmed that when a normal image signal is displayed, a state of zero photoelectric conversion output is obtained during the vertical blanking period, and the process of canceling and removing the ambient light component is performed. finish.

Finally, a flowchart showing the process of processing the photoelectric conversion output signal is shown in FIG.

In the signal processing process shown in FIG. 6, first, in step S81, the white balance operating condition setting counter 23 is cleared, and then in step S8
2. The process moves to step S84 via S83, and it is determined whether or not there is a peak detection value in the photoelectric conversion output.
Next, after confirming in step S85 that the peak detection becomes zero only during the vertical blanking period of the input image signal, the process proceeds to step S87, where the photoelectric conversion output is sampled, and in the next step S88, the photoelectric conversion output is sampled. Digitize the sample value.

Next, the process proceeds to step S90 to check the white balance adjustment state during the vertical retrace period, and then
Proceeding to step S92 via step S91,
The sample value is set as the initial value of the counter 23. Next, in step S93, the above signal processing process is checked, and then in step S9
4, the upper set being output from the counter is confirmed and the signal processing process is completed.

[Effects] As is clear from the above description, according to the present invention, changes in the characteristics of various circuit elements, especially color display tubes, and changes in ambient conditions, especially ambient light, during white balance adjustment in a color image monitor can be avoided. Since the correction is made with reference to the reference initial adjustment value, highly accurate sequential white balance adjustment can be achieved with a circuit device having a simple configuration.

In general, sequential white balance adjustment is
It is said that it takes a long time to adjust compared to the simultaneous adjustment type, but according to the present invention, it is possible to complete a series of adjustments within a few seconds by automating the adjustment using an appropriate sequence, so there is no problem in practical use. do not have.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the color image monitor white balance adjustment device of the present invention, and FIG. 2 is a block diagram showing an example of its detailed configuration.
Figures 3A-C, Figures 4A, B, Figures 5 and 6
The figure is a flowchart sequentially showing the processing steps at various stages of white balance adjustment. 1... Calibration signal source, 2R, 2G, 2B... Attenuator, 3R, 3G, 3B, 11M, 11S... Amplifier, 4... Color display tube, 5R, 5G, 5B...
...Adjustment control unit, 6H, 6L...Holding memory, 7
H, 7L...Reference memory, 8H, 8L, 30...
Comparator, 9... Optical sensor probe, 10M...
Main photoelectric conversion element, 10S...Sub-photoelectric conversion element, 1
2...Trimmer resistor for external light offset adjustment, 13...Subtractor, 14-1, 14-2...Mode selection switch, 15-1 to 15-4...Manual selector switch, 16...Switch for initial setting , 17-
RH, 17-GH, 17-BH...Amplifier initial setting switch, 17-RL, 17-GL, 17-BL
...Attenuator initial setting switch, 18-RH, 1
8-GH, 18-BH, 18-RL, 18-GL,
18-BL...variable resistor for initial setting value input, 20
Y...Luminance signal source, 20C...Chromaticity signal source, 21
...Matrix circuit, 22, 22R, 22G,
22B...D-A converter, 23...Counter, 2
4... Limiter, 25... Control unit, 26...
...Peak hold circuit, 27...A-D converter,
28... Average value circuit, 29... Memory device, 31
R, 31G, 31B...γ correction circuit.

Claims (1)

[Claims for Utility Model Registration] 1. An adjustment signal for generating a reference input image signal for each primary color in a color image monitor equipped with a color display tube and signal level adjustment means and amplification means for each primary color for input image signals. a photoelectric conversion means for receiving display image light of the color display tube; a memory means for storing a reference level corresponding to the reference light of the color display tube; and a converted output from the photoelectric conversion means and the memory means. a comparison means for comparing the reference level read from the control signal source; and a display on the color display tube when reference input image signals of at least a high signal level and a low signal level are sequentially supplied for each primary color from the adjustment signal source. Based on the comparison output from the comparison means corresponding to each image, the signal level adjustment means is feedback-controlled for each primary color for the high signal level, and the signal level adjustment means is feedback-controlled for each primary color for the low signal level. 1. A color image monitor white balance adjustment device, comprising: control means for feedback-controlling a clamp potential of the amplification means, wherein the control means sequentially adjusts the white balance of the color display tube. 2 Utility Model Registration Scope of the Claims The device according to claim 1, comprising auxiliary photoelectric conversion means for receiving external light incident on the color display tube, and converting the conversion from the photoelectric conversion means by the conversion output of the auxiliary photoelectric conversion means. A color image monitor white balance adjustment device characterized by correcting output. 3 Utility Model Registration In the device according to claim 1 or 2, means for switching the circuit connection corresponding to the high signal level and the circuit connection corresponding to the low signal level in a predetermined order for each primary color. A color image monitor white balance adjusting device comprising: a white balance adjusting device for automatically adjusting the white balance of the color display tube.