JPS6361830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an imaging system that selectively outputs a plurality of video signals captured by a plurality of television cameras.

For example, a switcher with a built-in special effects device may be used for the output of multiple television cameras. Naturally, the phases of the signals from each camera output from the switcher (the phase of the horizontal synchronization signal H in the case of black and white, and the phase of the color subcarrier SC in the case of color) must match. be. This adjustment is generally performed by using H-adjustment and SC-adjustment knobs provided on the camera to correct the phase shift caused by the cable delay between the camera and the switcher. In conventional switchers, the switcher itself is equipped with a meter or lamp, and the phase state of the signal can only be monitored from the switcher side. Therefore, if the camera and switcher are installed far apart, it is very difficult to make adjustments.
We needed to communicate through intercom.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an imaging system in which a cameraman himself can monitor the phase relationship between the phase of the camera he operates and the reference signal. .

An embodiment of the present invention is shown in FIG. 1, in which a case is shown in which the phase state between three television cameras is monitored.

In the figure, reference numerals 1, 2, and 3 indicate color television cameras, each of which is equipped with electronic viewfinders 4, 5, and 6 each having a built-in cathode ray tube of about 1.5 inches. A color television camera 6 is attached to a caption card photographing stand 7. In this case, the camera may be a black and white camera.

In the example shown in FIG. 1, the output from the synchronization generator 9 built into the switcher 8 is supplied to each television camera 1, 2, and 3, and the basic synchronization relationship between the cameras is maintained. . Synchronous generator 9
receives an internal synchronization signal and a subcarrier from terminals 10 and 11, for example, and generates a reference signal. Each television camera and switcher 8 are further connected to each other by two signal lines. One is the camera video signal, and the other is the return video signal. Each camera has input signal changeover switches 12, 13 and 14 for the electronic viewfinder 4, 5, 6.
It is equipped with a camera video signal and a return video signal that can be switched and displayed on the monitor. Furthermore, each camera has a horizontal adjustment volume 1.
5, 16 and 17 and subcarrier adjustment volume 1
8, 19, and 20, and the horizontal synchronization phase and subcarrier phase of the output camera video signal can be arbitrarily adjusted.

The camera video signal supplied from each camera is
Only one is selected by the switches 21, 22 and 23 and output from the output terminal 27. switch 2
1, 22, and 23 are linked to push buttons 24, 25, and 26 on the operation panel of the switcher 8, and in the example shown in the figure, the push button 25 is operated and the output of the color television camera 2 is selected. .
The camera video signal thus selected is supplied to the output terminal 27 as described above, and is superimposed with a signal phase display signal in the mixing circuit 28, and is sent to each viewfinder 4, 5, and 6 as a return video signal.
supplied to

Now, the phase display signal is generated as follows. That is, the camera video signals selected by switches 21, 22, and 23 are supplied to a horizontal synchronization signal separation circuit 29, where the horizontal synchronization signals are separated. The thus separated horizontal synchronization signal is supplied to the phase comparator 30 and compared with the reference horizontal synchronization signal from the synchronization generator 9. This phase comparator 30 operates to output a "1" output if the two input horizontal synchronizing signals are in phase, and to output a "0" output if they are out of phase. The output of the phase comparator 30 is applied to AND circuits 31, 32 and 33, which gate the output pulses of the pulse generator 34. Pulse generator 3
4 receives a reference horizontal synchronization signal and a vertical synchronization signal from a synchronization generator 9, and outputs a pulse signal for horizontal line display. That is, when three television cameras are connected, the pulse generator 34 has three output lines, which are connected to AND circuits 31, 32, and 33, respectively.

If the current standard vertical synchronizing signal is shown in FIG. 2A, the respective output lines of the pulse generator 34 are shown in FIG.
As shown by C and D, pulse signals generated at each timing of dividing one vertical scanning section into four approximately equal parts are obtained. Each pulse is a signal that is at the "1" level during one horizontal scanning section, and becomes a signal corresponding to three horizontal lines indicated by L1, L2, and L3 on the screen of the viewfinder shown in FIG.

The AND circuits 31, 32, and 33 are provided with short switches 35, 36, and 37 that are linked to the operation of the push buttons 24, 25, and 26, respectively, so that only the switch corresponding to the selected push button is opened. It is composed of Therefore, only the AND circuit corresponding to the selected camera controls the passage of the pulse for horizontal line display from the pulse generator 34 according to the output of the phase comparator 30, and the other pulses for horizontal line display are always passed through the AND circuit. is obtained on the output side. their respective
The output of the AND circuit is superimposed on the return video signal by an OR circuit 38 and mixing circuits 39 and 28.

A subcarrier phase display signal is applied to the mixing circuit 39 from a multiplier circuit 48 . This subcarrier phase display signal is generated as follows.

First, the burst gate circuit 40 extracts a color burst signal from the selected camera video signal, the oscillator 41 generates a subcarrier based on the extracted burst signal, and the phase comparator 42 generates a subcarrier from the synchronous generator 9. Perform phase comparison with reference subcarrier. The output of the phase comparator 42 is given to an integrating circuit 43, which supplies a DC voltage according to the phase difference to a voltage comparator 45. On the other hand, this voltage comparator 45 has a triangular wave generation circuit 44 triggered by a reference horizontal synchronization signal from the synchronization generator 9.
output is supplied. That is, if FIG. 4A is used as a reference horizontal synchronizing signal, the output of the triangular wave generating circuit 44 is shown in FIG. 4B, and the output of the integrating circuit 43 is shown by a dashed line in FIG. 4B. The voltage comparator 45 obtains a pulse in which only the part of the triangular waveform that exceeds the dashed line is "1", and the delay circuit 46,
A vertical line display pulse shown in FIG. 4F is obtained by a subtraction circuit 47 and a multiplication circuit 48 for aligning the polarity of the pulses. This vertical line display pulse is the third
On the viewfinder screen shown in the figure, L5,
This is the signal corresponding to the vertical line of L6. Furthermore, Figure 4D
is the output of the delay circuit 46, and E in FIG. 4 is the output of the subtraction circuit 47.
The output of each is shown.

The usage method and operating state of the inter-camera signal phase display device provided in the imaging system of the present invention are as follows.

First, when the color television camera 2 is selected as shown in FIG.
compares the phases of the horizontal synchronization signal and color burst signal in the camera video signal from the color television camera 2 with the phase of the reference signal. For example, if the phases of the horizontal synchronizing signals do not match, the pulse on the second output line of the pulse generator 34 will not appear in the output of the AND circuit 32. Therefore, if the switch 13 of the color television camera 2 is turned back to the video side, the horizontal line L2 shown in FIG. 3 will not be displayed in the phase display signal superimposed on the video signal. Therefore, the cameraman adjusted the level adjustment volume 1.
6 to the position where the horizontal line L2 appears. That is, when the phase of the camera video signal is shifted by adjusting the horizontal adjustment volume 16 and matched with the phase of the horizontal synchronization signal from the synchronization generator 9, the output of the phase comparator 30 becomes "1" and the switch 36 is opened. However, the pulse signal for the horizontal line L2 is superimposed on the returned video signal through the AND circuit 32.

Further, the phase of the subcarrier is determined by a phase comparator 42 and an integrating circuit 43, and a voltage corresponding to the phase difference is supplied to a voltage comparator 45. If we design the integrator circuit 43 so that when the phases match, the lowest voltage output is generated, and the voltage increases as it deviates from that point, then when the phases match, the vertical lines L5 and L6 The gap is widest,
It becomes narrower as it shifts. The cameraman uses the color television camera's subcarrier adjustment volume 1.
Turn 9 and use view index 5 to draw vertical lines L5 and L6
Adjust and fix at the position where the distance between is widest.

After the above-mentioned adjustments are made for each of the color television cameras 1, 2 and 3, they are put into actual use. After completing the adjustment, horizontal lines L1, L2, L3
and vertical lines L5, L6 may not be superimposed on the return video signal. However, as in the above-described embodiment, if the lines are superimposed even when not being adjusted, it can be advantageously used as a reference line for positioning the caption card when photographing the caption card, as in the case of the color television camera 3.

Although the present invention has been explained using a simple switcher as an example, the switcher may be equipped with a more complicated special effects device, and the phase alignment may also be based on the output of the color television camera 1, for example. The signals may be combined with signals from other cameras. Various modifications of the display signal are also possible. In the embodiment of FIG. 1, only the phase status of the selected color television camera is displayed, but it is also conceivable to display the status of all connected cameras.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a waveform diagram used to explain a display signal regarding the horizontal synchronization phase in an embodiment of the present invention.
FIG. 3 is a schematic diagram showing a mode of phase display on the screen of the viewfinder, and FIG. 4 is a waveform diagram used to explain a display signal regarding the subcarrier phase in one embodiment of the present invention. Each of 1, 2, and 3 is a color television camera; each of 4, 5, and 6 is an electronic viewfinder;
8 is a switch, 15, 16, 17 are horizontal adjustment volumes, 18, 19, 20 are subcarrier adjustment volumes, 27 is an output terminal, and 28 is a mixing circuit.

Claims (1)

[Claims] 1. In an imaging system comprising a plurality of television cameras having a viewfinder and a switching device that selectively outputs a plurality of video signals inputted from the plurality of television cameras, a first a forming circuit that compares the phase of the video signal with the phase of the reference signal and forms a phase difference signal indicating the phase difference between them; and a synthesis circuit that combines the phase difference signal and the first video signal. An imaging system characterized in that the switching device is provided, and the output signal of the combining circuit is input to a viewfinder of the first television camera for display.