JPS5963891A - Registration circuit of image pikcup tube - Google Patents

Abstract

PURPOSE:To adjust registration finely by adding a compensating waveform corresponding to each scanning of respective horizontal and vertical saw tooth waves to control the position of an electron beam. CONSTITUTION:An address pulse formed from a horizontal synchronizing pulse and a vertical synchronizing pulse drives an address generating circuit 81 and scans memories 71, 72. The outputs read out from the memories 71, 72 are converted into an analog value and supplied to both ends of a resistance group 75. The resistance group 75 is connected to a switch group 76 and the prescribed switch of the switch group 76 is successively opened and closed in accordance with the scanning of the synchronizing pulse.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a deflection circuit for a television camera, and particularly to a deflection circuit for a television camera.
The present invention relates to a registration circuit in a television camera using a plurality of image pickup tubes, such as a tube-type color camera.

[Prior art]

BACKGROUND ART Conventionally, so-called 3F type color cameras, in which image pickup tubes are assigned to respective primary colors, as shown in FIG. 1, have been used in television broadcasting operations and applications requiring high quality images. In FIG. 1, 11 is a taking lens, 12 is a three-color separation optical system, 13, 14, 15 is an image pickup tube corresponding to each primary color of R, G, B, and these pigeon tubes 13, 14.
The final television signal is created by amplifying and signal processing each of the 15 outputs. The above example is 3 as mentioned above.
It is a type of camera called a tube color camera, but as a different type of camera, the luminance signal is obtained from one image pickup tube, and the color number 1d is obtained from another image pickup tube. There are tube-type color cameras and four-tube color cameras that have a fourth image pickup tube for detecting luminance signals in addition to R, G, and B primary color signals. A technique common to these multi-tube color cameras is so-called registration adjustment, which adjusts the images of each image pickup tube. Generally photographed/
In television cameras using a hollow tube, various graphical distortions occur due to processing errors in the electron gun of the image pickup tube, manufacturing errors in the deflection coil assembly, and electro-optical distortions unique to the deflection method, which are related to both. In conventional multi-tube color cameras and especially measurement cameras where figure distortion is a problem, a method of correcting these figure distortions is to add a parabolic waveform or sawtooth shape to the deflection current (or voltage) waveform, as shown in Figure 2. The deflection waveform is modulated by the correction waveform. Figure 2 21 is an example of the deflection current (voltage) waveform, 22
shows a parabolic waveform as an example of a correction waveform.

23 shows a waveform obtained by superimposing the parabolic correction waveform 22 on the deflection current (voltage) waveform 21. This allows the linearity of deflection to be varied. The waveform 24 is an example in which the horizontal deflection current (voltage) waveform in a television camera is modulated by a parabolic waveform with a constant vertical distortion period. As a result, as shown in FIG. 2 (11), horizontal barrel distortion can be corrected (changed in the direction of the arrow) on the television screen.

As shown in the above example, conventional methods for correcting graphic distortion by deflection correct only low-order distortions among graphic distortions. However, in recent years, in multi-tube color cameras, etc., there has been an increasing demand for highly accurate registration adjustment, and conventional correction of only low-order distortion has become unable to meet these demands. . In particular, the required accuracy of registration is particularly high for high and 1-slim television cameras, which have a larger number of casings than the current television system (525).

Therefore, recently, a registration circuit using a computer and memory has been developed for the purpose of correcting even high-order distortion. However, in order to correct high-order distortion using these circuits, not only must the calculation speed be fast, but also complex calculation processing is required, which requires large-scale and high-speed calculation circuits and memory, so cost must be taken into account. In other words, the best method is dl/'1 away.

[Purpose of the invention]

Therefore, the gist of the present invention is to improve this point.

[Detailed description of the invention]

Before explaining the present invention, the correction method will first be outlined. As shown in FIG. 3, a method has been used in recent years in which a television screen is divided into a horizontal division and a vertical division, and a correction value is given to each of these squares. The values of the division numbers a and b are determined depending on how high-order distortion can be corrected.

The correction values given to each square must be read out in order according to the scanning cycle, and once the Uramasa value is determined, the same value must be read out for each frame or field frequency. That is, a non-destructive memory is required to store the correction value for each square. Furthermore, in this method, one correction value is given to each square, so when scanning between adjacent correction values in the horizontal and vertical directions, a correct value must be obtained through interpolation. Figure 4 shows this situation. Now assume that the horizontal direction of the screen is H1 and the vertical direction is V, and a correction value is given to each intersection of the squares in the figure. When the amount of correction value is shown in the Z-axis direction, the amount of correction can be represented by a curved surface connecting each intersection point as shown in FIG. Between intersection P11 and P21, P
The sections between 21 and Pal, . . . , are each composed of n horizontal scanning lines Lo yLpt -1 . . . . Since only the value of each intersection point is given as the correction amount, it becomes necessary to calculate the correction values read out in accordance with the actual scanning in the horizontal and vertical directions. This will be called an interpolation operation. First, the vertical interpolation operation will be explained. Now consider the pH and pit between each intersection 1. This is approximated by a straight line in the vertical direction. That is, the correction value for the n scanning lines between pH and P21 uses the value on the straight line connecting Prt and Pal. That is, in the first scan, line Lo, Plt +
The value is read as PI3 +Prs..., and after the second scanning line Lt... (1) (k is the scanning line number: o, 1.2,・・・・・・
・N-1, n is a constant) It is necessary to read while calculating.

Next, the horizontal interpolation operation will be explained. In the horizontal direction, that is, the first scanning line Lo, ptt I PI3 +P1
3..., and at the M2th scanning line L1, the interpolated value is read out according to equation (1). That is, in the horizontal direction, if the reading period of pH*pH*Pts is now T, the correction information is sampled at a period T as shown in FIG. 5(1). Therefore, it is a well-known fact that the sampling theorem can represent information up to the Nyquist limit of Kaede sampling, that is, up to a frequency of 1/2T. Therefore, in sampling period T, by passing it through a 1/2T low-pass filter, it is easy to obtain a continuous signal (Fig. 5 (i+)).
'e can get it. As described above, it can be understood that horizontal interpolation can be easily achieved simply by passing the signal through a low-pass filter having a cutoff frequency of 1/2 or less of the sampling frequency.

In this way, with the method of dividing the horizontal direction a1 vertical direction into squares and giving positive horizontal and vertical rlfl values for each square, if vertical interpolation is possible, horizontal direction can be obtained by simply smoothing the information of each point. It will be done.

Using the correction waveform obtained in the above manner, finely distort the figure for each square. Shape wave generation circuit 51 and vertical sawtooth wave generation circuit 56
The correction waveforms corresponding to the vertical and horizontal scanning obtained from the correction waveform generation circuit 54 are added to the horizontal and vertical sawtooth waves generated by the respective adding circuits 53 and 55, and the outputs are added to the horizontal and vertical sawtooth waves generated by the horizontal deflection circuits 52 and 52, respectively. In addition to the vertical one-plane circuit 57,
The electron beam position of the control coil 5El and the 'if moving imaging' α59 can be determined using the output of the i trapping circuit.

If this operation is performed for each RGB tube, the registration layer 7 can be adjusted by 1lttl more than in the past, and a better quality screen can be obtained.

〔Example〕

The gist of this book is how to create a correction waveform in response to scanning. The sawtooth wave generating circuit, polarization circuit, and other circuits necessary for a general three-tube color camera are already well known, so their explanation will be omitted here. In the present invention, only the correction waveform generation circuit 54 will be explained.

The present invention will be described in detail below using examples.

Consider moving point P22 to point P22' on the screen in Diagram 7. To do this, a correction voltage corresponding to the distance En is applied to the horizontal deflection waveform at the time point P22 is scanned, and 41
Just add the appropriate correction voltage. this? ii Positive values ER and Ev need to be independent of each other. In other words, two independent correction values are required for one intersection point.

The following discussion describes how to generate one of the two correction values. Another value or another one of 3 tubes
The Urasa value generation method for a single image tube can be realized in exactly the same way, so the explanation will be omitted.

FIG. 8 shows an embodiment of the present invention. In Figure 7, Lo
In order to obtain the vertical interpolation value of n lines from N N -1 for each horizontal line, the value of the intersection point pH and P21
s PI3 and P22\P13 and P23 are required at the same time. This is also clear from equation (1).

The basic concept of interpolation of the present invention is as shown in FIG. 8 (1), P11T'P12→P1. A power source E1 that generates correction values in the order of → and a power source E2 that generates correction values in the order of P21-+P22→P23, etc. are provided, the gap between them is divided by n resistors, and a switch So is connected to each resistor end. I 81
mS2...S N-1 is connected, and this Sw'z
The purpose is to obtain interpolated values in the vertical direction by sequentially switching from So to 5N-1 in synchronization with horizontal scanning. Needless to say, when Er is outputting the value of Pu, %E2 is reading the value of P21. Figure 8 (11)
is a detailed block diagram containing the surrounding casing.

In the case of the present invention, bl I E2 must generate the same value n times while scanning n scanning lines. Therefore, a memory capable of non-destructive reading is required as a means for accumulating the correction values of these intersection points. This time, we will show an example in which a digital memory is used as this memory. Memory 71 corresponds to El, and memory 72 corresponds to E2. Generally, there are a memory circuit (TE, :, i-person cover I, output port 01 address (address designation) baud) AD, a terminal W for opening input and readout, and the like. The same correction value is written in the memory 71 and the memory 72. As described above, the memo IJs 71 and 72 have different read addresses. To simplify the explanation, a=3, b==3, and n=3 as shown in FIG.
)71.72 The order of readout correction values is shown in Figure 9 (+oM
1. It becomes as shown in M2. On the first scanning line Lo, the memory 71 has a pH of pH ~ P14, and the memory 72 has a pH of P21 ~ P.
It will be 24. Second scanning line Ll) On the third scanning line L2, the same value as Lo is repeatedly read out, and L3~
Up to L5, the memory 7e reads P21 to P24 and the memory 72 reads P31 to P34 repeatedly three times. Reading is performed in the same manner thereafter. The outputs thus read out are converted into analog values by the D/A converters 73 and 74 (11) in FIG. 8, and are applied to both ends of the resistor group 75. From the resistor group 75, as shown in FIG. 8(1), l'i:S
W group 76 S Wt # S Wz s S Wa are connected. This 8W group 76 is opened and closed at the timings S Wo , S Wl , S Wz , etc. shown in FIG. 9 (11). This pulse can be easily converted to a star (+ pulse) by dividing the horizontal synchronizing pulse of the synchronizing signal generation period 77 by 3 using a counter 80 (ST pulse in FIG. 9) and using the shift register 78 clocked by the horizontal synchronizing pulse HD. All the outputs of the 8w group 76 are combined and taken out as a continuous signal by a hold circuit 79.

The addresses for driving the memories 71 and 72 are generated by the address generation circuit 81 (the address order is shown in FIG. 9(il) M11).
As shown in M2). These address pulses can be easily generated from horizontal synchronization pulses, vertical synchronization pulses, etc., so their explanation will be omitted.

Next, a method for rewriting part of the correction value information stored in the memories 71 and 72 will be described.

TV has a retrace period both horizontally and vertically as shown in No. 3. Since it is not displayed on the image during the retrace period; 1JJ
If it is used during the f:t replacement period, it will be possible to replace i'F with ease in terms of timing. In other words, Figure 8 (1
In step 1), the control signal generator 82 sends the signal of the address to be rewritten to the address generation circuit 81, and as shown in FIG. The address ADX is generated. At this time, since the memories 71 and 72 to be rewritten must have the same address, it is necessary to send the same address to the memories 71 and 72 by the switching circuit 83. The switching timing of the switching circuit 83 at this time is shown by SW in FIG. 9 (0il). A write enable terminal (W) is usually provided to put the memory into a write mode. Only when a pulse is applied here, the memory enters the death mode.

The timing of this W pulse is shown by W in FIG. 8 G10.

In other words, it is sufficient if it is after the address is determined but before the address signal changes. It is unnecessary to explain that these control signals can be easily generated by the control signal generator 82.

To generate the information to be rewritten next, as shown in FIG. 8 (11);
It can be easily generated using an A/D converter 86 that converts this 'analog value into a digital value.

In addition, although two memories are used in FIG. 8(ii), if the readable time of the memory is less than half of the required read cycle, it is also possible to sequentially read data from one memory in a time-sharing manner. That is, as shown in FIG. 1O (1), the address of the memory 91 is as shown in FIG. 10 (11),
The memory output is set by the switch circuit 92.
Separate into (Fig. 10 (II)) L, each output D/
A/NO (-E) are converted into analog quantities at 93 and 94, respectively.The respective analog outputs ftMo' are shown in Fig. 10 (
At timing T1 in Figure 10 (11), Mo'' performs sample and hold in the sample and hold circuits 95 and 96, respectively, at timing T2 in Figure 10 (11). That is, the sample and hold output waveform ((81) in Figure 10 (11)) is the output waveform of the sample hold circuit 96 (Fig. 10 (11)
(82)) is output half a pitch ahead. Therefore, if the sample and hold circuit 97 performs the sample and hold operation again at the timing T2 in FIG. 10 (11), it will coincide with the timing 82 as shown in Si2 in FIG. 10 (11). This sample hold circuit 97
It will be understood that if the outputs of the circuits 96 and 96 are respectively applied to the resistor group 75 shown in FIG. 8(1i), a similar operation can be performed.

〔Effect of the invention〕

As mentioned above, according to the present invention, it is possible to match the multi-tube registration with higher precision to every corner of the screen compared to the conventional method, and it is possible to configure a multi-tube color camera with better performance. becomes possible. It is clear that the present invention can be used not only for registration but also as a correction waveform generator for a shading correction circuit for television signals. Furthermore, the present invention has a wide range of applications as it can be used as a correction waveform generator for a convergence circuit of a color television receiver.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a three-tube color camera, Fig. 2 is a conceptual diagram showing the interpolation method, Fig. 6 is an explanatory diagram of a general correction method for registration oil stop, and Fig. 7 is a conceptual diagram of the method of interpolation between the two. A conceptual explanatory diagram of the registration 1 regular method, FIG. 8 is an embodiment of the present invention, FIG. 9 is an example of a timing chart in the embodiment of the present invention, and FIG. 10 is another example of the memory configuration method in the embodiment of the present invention. An example of the embodiment and its timing chart is shown below. ' -l. Cheer 7 〃 ゝ、jsz Go 2 Punishment 5 Figure 6 Figure, Sl Figure 7 Expanded Figure (i)

Claims (1)

[Claims] A memory circuit that divides a television screen horizontally and vertically and stores correction amounts at intersections thereof, a circuit that divides the output of the memory circuit, a group of switches that selectively switches the output of the circuit, and A registration circuit for an image pickup tube, comprising a shift register for sequentially opening and closing a group of switches.