JPS6113677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring misconvergence in color television using a monochrome ITV camera as a detector.

First, a conventional example of a color television misconvergence measuring method using a monochrome ITV camera will be described.

As shown in Figure 1, the ITV camera 2 is installed in front of the color TV 1 to be measured so that it can capture the entire screen.
to take a picture of the color TV screen. At this time, on a screen with poor convergence, for example, when trying to display a single white vertical line, the lines are red (hereinafter abbreviated as R), green (hereinafter abbreviated as G), blue (hereinafter abbreviated as G), and blue (hereinafter abbreviated as G), as shown in Figure 1. , B)).

The amount of deviation of these three primary colors can be calculated from the camera video output obtained when camera 2 scans (scanning position A) the three primary colors developed on the TV side by sequentially switching them, and is determined by t _R , It is obtained by measuring t _G and t _B . Said t _R , t _G , t _B
are the amount of time from the horizontal synchronization signal to the peaks of the R, G, and B detection waveforms, respectively.

Therefore, in the prior art, when determining the values of t _R , t _G , and t _B , the colors must be sequentially switched. On the other hand, when viewed from the ITV camera side as a detector, a refresh time is required in response to changes in the subject. This is called the rising and falling afterimage time and is generally known.

When this measurement is viewed as work to be performed before misconvergence adjustment, as is well known, this measurement and adjustment will be repeated.

That is, for example, t _R is measured by coloring an R vertical bright line in one field, and then after the R bright line disappears, a B vertical bright line is colored and t _B is measured.
An adjustment mechanism such as a convergence magnet is operated so that the difference becomes zero. Next, the R and B horizontal bright lines are similarly colored in one field, the difference between them is measured, and an adjustment mechanism such as a convergence magnet is operated so that the difference becomes zero. In this way, normally, the vertical bright line and the horizontal bright line are colored alternately, and the convergence deviation measurement and adjustment are repeated to converge to the correct convergence state. Now, this combined work of measurement and adjustment _{is necessary} to adjust the horizontal deviation.
Alternatively, if the vertical direction misalignment adjustment is performed N _V times, the adjustment time T for correcting the R and B color misalignment, for example, is expressed by equation (1).

T = {(16.7 ^ms + t _d ) x 2 colors + t _M } ( _NH + N _V )
...(1) Here, t _d : ITV camera afterimage removal waiting time (ms) T _M : Adjustment mechanism operation time
(ms) N _H : Number of repetitions of measurement and adjustment required to correct color deviation in the horizontal direction of R and B. N _V : Number of repetitions of measurement and adjustment required to correct color deviation in the vertical direction of R and B. Number of times: 16.7 ^ms : 1 field scanning (measurement) time (60
Hz) Currently, the expected afterimage elimination waiting time t _d for an image pickup tube with flat spectral sensitivity to the three primary colors R, G, and B and high detection sensitivity is about 80 ^ms . This means that approximately five times as much wasted time is wasted as compared to the minimum measurement time required to detect the peak position of a bright line of one color, that is, one field time of 16.7 ^ms .

As is clear from the above, if the dead time included in the adjustment time T expressed by equation (1) is minimized, the efficiency of the adjustment device can be improved.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a convergence measurement method that eliminates the above-described drawbacks of the prior art and can shorten the convergence adjustment time.

The gist of this invention is to display a line pattern (vertical or horizontal bright line) made of two colors on the same screen, and to complete pattern position measurement for two colors within one field. This is based on experimental confirmation that there is almost no difference in data (convergence deviation) in the vicinity of the measurement point 31 in FIG. 1.

As a result, data on the convergence deviation for two colors, for example, R and B, can be obtained in one field time, and since the afterimage elimination waiting time for one color is eliminated, it is equivalent to →
One color, t _d =0 can be used. However, since two colors are displayed on the same screen in this way, the color switching time t _d is not required, but it is necessary to give the conventional waiting time t _d to switch the vertical and horizontal lines of the line pattern.

FIG. 3 is a block diagram of a color television image conditioning apparatus suitable for implementing the method of the present invention. 1 is a color cathode ray tube screen, 2 is a deflection yoke, 3 is a magnet ring, 4 is an ITV camera for detection, 5 is a video switch, 6 is a peak position detector, 7 is a time measuring device, 8 is a CPU, 9 is a line selector , 10 is a synchronizing signal, 11 is a deflection yoke/magnet drive mechanism, and 12 is a pattern generation/color switching circuit.
A pattern is generated by the pattern from the CPU 8 and a color switching control signal 22, and a cathode cathode signal 23 is supplied from the color switching circuit 12 to the cathode ray tube. ) Projects bright lines. The bright line is photographed by a black and white ITV camera 4, and the video signal 1 is
3, t _R , t _G , t _B shown in FIG. Convert to Thereafter, a mechanism control signal 21 is generated based on this data, and the drive mechanism 11 adjusts the positioning of the deflection yoke 2, magnet ring 3, etc. attached to the color cathode ray tube.
In FIG. 3, the line selector 9 has a function of extracting camera scanning signals passing through a point to be measured, and is sequentially switched by the CPU depending on the measurement location.

Further, 14 is a necessary scanning line signal, 15 is a waveform peak position detection signal, 17 is a time measuring device reset signal,
18 is a time measuring device start signal (horizontal synchronization signal), 19 is measurement point scanning line number data, and 20 is a synchronization signal.

Among these, the measuring method according to the present invention is carried out in the following steps. However, here, an example of measurement of data (convergence shift) for one point each of the red and blue vertical lines is shown.

(1) Generate a pattern so that the upper half of the screen to be measured is blue and the lower half is red, and give the CRT cathode signal 23 from the color switching circuit 12.

(2) Apply a white vertical single line pattern from the pattern generator to the color cathode ray tube to be inspected, and project blue and red vertical single line patterns 33 and 34 on the cathode ray tube screen 1 as shown in Figure 4. .

3 Use the line selector 9 to set the measurement point to D _B from the top of the screen. That is, the D _Bth scanning line 35 (FIG. 4) is selected by the line selector 9, and the waveform peak position of the scanning line signal 14 output from the video switch 5 is detected by the peak position detector 6. The detection signal 15 is supplied to the time measuring device 7 to measure t _B , and the obtained data 6 is transferred to the CPU 8 .

(4) Shift the measurement point down by d (D _B +d) and set it to the actual measurement point. That is, the line selector 9 selects (D _B +d)th scanning line 36 (fourth
), measure t _R in the same manner as above, and transfer the obtained data to the CPU 8.

(5) The amount of misconvergence (t _R −t _B ) is calculated in the CPU 8, and the mechanism control signal 21 necessary for adjusting the misconvergence is sent to the deflection yoke.
It is supplied to the magnet drive mechanism 11.

6 The deflection yoke magnet drive mechanism 11 is operated by a suitable actuator to
(and deflection yoke 2), and
The bright lines 33 and 34 shown in the figure are aligned on a straight line, and the convergence in the lateral direction is made zero.

(7) Pattern generation and color switching circuit 12 so that the left half of the screen to be measured is blue and the right half is red.
A cathode cathode signal 23 is applied to the cathode ray tube to display a horizontal single line pattern consisting of two colors.

(8) In the same manner as described above, measure the vertical convergence shift and align the blue pattern and red pattern on a straight line.

9 Repeat the misconvergence adjustment in the horizontal and vertical directions.

As is clear from the above description, the misconvergence measurement/adjustment time according to the present invention can be equivalently set from two colors to one color, t _d =0, in the equation (1). Therefore, the misconvergence measurement/adjustment time T' according to the present invention is expressed by equation (2).

T' = (16.7 ^ms + t _M ) ( _NH + N _V ) + N _HV・t _d
...(2) However, N _RV is the number of vertical and horizontal switching of the line pattern,
Therefore, the time saving effect is expressed by equation (3).

1-T'/T=(16.7 ^ms + _tM )( _NH + _NV )+ _NHV・_td /{( ^16.7ms + _td )×2 colors+
t _M } ( _NH ) + N _V )...(3) Now, based on the data at the current technological level, specifically t _d = 80 ^ms , t _M = 10 ^ms , N _HV = 20,
By substituting representative values such as N _H +N _V =100, it can be seen from equation (3) that a time reduction effect of 79% can be obtained. That is, according to the present invention, the adjustment time can be reduced to 21% of the conventional technique, and the above-mentioned drawbacks of the conventional technique can be solved.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the principle of misconvergence measurement according to the prior art, and Figure 2 is the same as in Figure 1.
An output waveform diagram of an ITV camera, FIG. 3 is a block diagram of a color television image adjustment device suitable for implementing the measurement method of the present invention, and FIG. 4 is a cathode ray tube screen for explaining the misconvergence measurement method of the present invention. FIG. 1... Color cathode ray tube screen, 2... Deflection yoke, 3... Magnet ring, 4... ITV for detection
Camera, 6...Peak position detector, 7...Time measuring device, 8...CPU, 9...Line selector, 1
0... Synchronization signal generator, 11... Deflection yoke, magnet drive mechanism, 12... Pattern generation, color switching circuit.

Claims (1)

[Claims] 1 A method in which at least two of the three primary colors red, blue, and green are used on the same field of a color cathode ray tube screen, and the colors are combined in such a way that the colors are swapped in the middle.1
Displaying the bright lines of a book as a test pattern, photographing the color cathode ray tube screen on which the test pattern is projected with a TV camera, and measuring the positions of the bright lines of each of at least two colors from the peak position of the video signal obtained by the TV camera, A misconvergence measuring method characterized by detecting a shift in the position of a bright line of each color as a shift in convergence.