JPH08265622A - Television camera with power supply superimposing system - Google Patents

Abstract

PURPOSE: To eliminate disturbance of image in the case of image switching by matching fields of video signals of each camera with each other without increasing the number of signal systems. CONSTITUTION: A power supply superimposing circuit 2 superimposes a vertical synchronizing signal S1 onto a power supply S0 and gives the resulting signal to a camera 1 and a video signal S2 is obtained from the camera 1. The video signal S2 is given to a synchronizing separator circuit 3, from which synchronizing signals are obtained, a field detector 4 detects a field S3 and it is inputted as one input of an exclusive OR circuit 5. A reference vertical synchronizing signal S4 generated by a reference vertical synchronizing signal generating circuit 6 is counted down into 1/2 by a counter 7 to generate a reference field signal S5 and it is inputted as the other input of the exclusive OR circuit 5. An output of the exclusive OR circuit 5 is subjected to NOT processing by a NOT circuit 8 and a vertical signal S1 to the camera is obtained by gating the reference vertical synchronizing signal S4 at an AND circuit 9. A television camera system comprising lots of cameras whose field signals are matched with each other similarly to other television cameras is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply superimposing television camera which superimposes a synchronizing signal and a video signal used in CCTV or the like on a power supply for transmission and driving.

[0002]

2. Description of the Related Art Conventionally, when signals from a plurality of power superimposition type television cameras are switched and displayed on one monitor, the fields (odd field or even field) between the cameras may not match. However, in this case, there is a problem that when the video signal of the camera is switched, the display image on the monitor is distorted (skew). There is also a method of sending a reset signal to the cameras to match them when a field mismatch occurs between the cameras, but in that case, there is a problem that it is necessary to further increase the signal system by one and superimpose it on the power supply. .

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is to match the fields of video signals of the cameras without increasing the signal system.

[0004]

In a television camera, a vertical synchronizing signal is superimposed on a power supply and sent to a television camera, and a PLL circuit is used in the camera to generate a synchronizing signal of a video signal synchronized with the vertical synchronizing signal. By providing a reference synchronization signal generating means and stopping the sending of the vertical synchronization signal to the camera when the field (odd or even) of the synchronization signal sent from the camera and the field of the reference synchronization signal do not match, Match the field of the sync signal of the camera with the field of the reference sync signal.

The field of the sync signal of the camera and the field of the standard sync signal are detected using the means for detecting the field of the sync signal sent from the television camera, the means for generating the field for the standard sync signal, and the means for comparing both fields. When the values do not match, the sending of the vertical sync signal to the camera is stopped, and the field of the sync signal of the television camera is made to match the field of the reference sync signal.

An exclusive OR circuit is used to compare the field of the sync signal of the television camera with the field of the reference sync signal.

By using the phase comparison means of the horizontal synchronizing signal of the horizontal synchronizing signal and the reference synchronizing signal sent from the television camera, when the phase of both signals is deviated, the sending of the vertical synchronizing signal is stopped and the television camera The field of the sync signal and the field of the reference sync signal are matched.

The horizontal sync signal pulse sent from the television camera and the horizontal sync signal pulse of the reference sync signal are ORed, and the output is used to reset the timer for outputting the pulse after a fixed period of time after reset. The vertical synchronizing signal is sent by using the output of the SR flip-flop, which is set by the output pulse and reset by the vertical synchronizing signal, as the gate signal.

When the PLL of the television camera is free running, the vertical synchronizing signal of the television camera is approximately 2 times the reference synchronizing signal.
Double the cycle.

[0010]

In the television camera, the vertical synchronizing signal is superposed on the power source and sent to the television camera, and the synchronizing signal of the video signal synchronized with the vertical synchronizing signal is generated by using the PLL circuit in the camera. With means,
When the field of the sync signal (odd or even) sent from the camera and the field of the reference sync signal do not match, the sending of the vertical sync signal to the camera is stopped, and when they do not match, the PLL in the camera does not It becomes a free run, the oscillation frequency of the VCO (voltage controlled oscillator) of the PLL becomes the lowest, and the period of the synchronizing signal is widened, so that the field shifts and eventually matches the field of the reference synchronizing signal.

The means for detecting the field of the sync signal transmitted from the television camera, the means for generating the field of the reference sync signal, and the means for comparing both fields are used to make the field of the sync signal of the camera and the field of the reference sync signal. If the values do not match, the sending of the vertical sync signal to the camera is stopped, and the field of the sync signal of the television camera is matched with the field of the reference sync signal, whereby the above configuration can be directly realized.

By comparing the field of the synchronizing signal of the television camera with the field of the reference synchronizing signal using the exclusive OR circuit, a field comparing means can be easily obtained.

By using the phase comparison means of the horizontal synchronizing signal of the horizontal synchronizing signal sent from the television camera and the horizontal synchronizing signal of the reference synchronizing signal, when the two signals are out of phase, the sending of the vertical synchronizing signal is stopped, and the television camera is stopped. The field of the sync signal and the field of the reference sync signal are matched. This is because even if the field shifts, the phase of the horizontal synchronizing signal shifts by 1/2 cycle, and the same purpose as described above can be achieved by detecting this and controlling the stop of the vertical synchronizing signal.

The horizontal synchronizing signal pulse sent from the television camera and the horizontal synchronizing signal pulse of the reference synchronizing signal are ORed, and the output is used to reset the timer for outputting the pulse after a fixed period of time after resetting. The above-mentioned means can be specifically configured by sending the vertical synchronizing signal by using the output of the SR flip-flop, which is set by the output pulse and reset by the vertical synchronizing signal, as the gate signal.

When the PLL of the TV camera is free running, the vertical sync signal of the TV camera is approximately 2 times the reference sync signal.
If the fields do not match and the sending of the vertical synchronization signal is stopped by setting the double cycle, the cycle of the vertical synchronization signal of the camera is doubled and the field of the reference synchronization signal is matched in the next cycle.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A power superimposing television camera according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of a power superimposition type television camera according to the present invention. The power supply S is applied to the TV camera 1 by the power supply superposition circuit 2.
The vertical synchronization signal S1 is superposed on 0 and sent, and the video signal superposed on the same power source from the camera 1 and sent out is separated by the power superimposing circuit 2 to obtain the video signal S2. The sync signal is separated from the video signal S2 by the sync signal separating circuit 3, and the field detector 3 detects the field from the difference in phase difference between the vertical sync signal and the horizontal sync signal depending on the field. It is used as one input of the circuit 5. On the other hand, the reference vertical synchronizing signal S4 generated by the vertical synchronizing signal generating circuit 6 serving as the reference is counted down by 1/2 by the counter 7 to produce the field signal S5 serving as the reference, which is used as the other input of the exclusive OR circuit 5. Exclusive Ethics circuit 5
Outputs a non-coincidence signal S6 which becomes logic 0 when the field S3 of the camera and the reference field S5 coincide with each other and ethics 1 when they do not coincide with each other. By denying this in the negation circuit 8 and gating the reference vertical synchronizing signal S4 in the AND circuit 9,
A vertical signal S1 to be sent to the camera is obtained. For other television cameras 11, the vertical sync signal S4 generated by the vertical sync signal generation circuit 6 serving as the reference and the field signal S5 serving as the reference are used to output the vertical sync signal to the camera 11 in the same manner as described above. The synchronization signal S11 is obtained. Similarly, a television camera system including a large number of cameras adapted to one reference field signal S5 can be constructed in the same manner.

FIG. 2 is a block diagram of another embodiment of the power superimposing type television camera according to the present invention. The TV camera 21 has a power superimposing circuit 22 and the power supply S20 has a vertical synchronizing signal S.
21 is superposed and sent, and the video signal superposed on the same power source from the camera 21 and sent out is separated by the power superimposing circuit 22 to obtain the video signal S22. The sync signal separating circuit 23 separates the sync signal from the video signal S22, the horizontal sync signal pulse S23 is detected, and it is input to one of the logical sum circuits 24. On the other hand, the horizontal synchronizing signal pulse S24 generated by the synchronizing signal generating circuit 25 serving as the reference is used as the other input of the OR circuit 24. When the field of the sync signal of the camera and the field of the reference sync signal from the logic circuit 24 match, the phases of both horizontal sync signals match, so the output signal S28 of the logic circuit 24 has the same cycle as the horizontal sync signal. However, when they do not coincide with each other, the phases of both horizontal synchronizing signals have a cycle of a half cycle shift of 1/2. Output signal S28 is 1/2 the horizontal sync signal
When the timer 26 set to a time slightly longer than the cycle is reset, the timeout pulse S25 is output when the phases of both horizontal synchronizing signals match, but when they do not match,
Since it is reset before the time-out, S25 is not output. This timeout pulse S25 causes SR
By setting the flip-flop circuit 27 and resetting it with the vertical synchronizing signal S26 from the synchronizing signal generating circuit 25,
The coincidence signal S27 is obtained. The reference vertical synchronizing signal S26 is gated by the coincidence signal S27 by using the AND circuit 29 to obtain the vertical synchronizing signal S21 to be sent to the camera. For other television cameras 31, a horizontal signal S24 generated by the reference synchronizing signal generating circuit 25 and a reference vertical synchronizing signal S26 are used to obtain a vertical signal S31 to be sent to the camera in the same manner as described above. . In the same manner, a television camera system including a large number of cameras adapted to one reference field signal can be constructed in the same manner.

According to another embodiment of the present invention, when a PLL for oscillating a clock for generating a synchronizing signal with a vertical synchronizing signal which is superimposed on a power source and sent to a television camera as a reference signal is a free run, PLL VC
By adjusting the oscillation frequency of O (voltage controlled oscillator) so that the vertical synchronizing signal of the TV camera has a cycle approximately twice that of the reference synchronizing signal, when the fields do not match and the sending of the vertical synchronizing signal is stopped. , PLL becomes free-run and the period of the vertical synchronizing signal of the camera is doubled, so that the vertical synchronizing signal of the television camera coincides with the field of the reference synchronizing signal in the next period.

[0019]

As described above, in a power superimposing television camera that sends a vertical synchronizing signal to synchronize each camera, if the field of each camera does not match the reference field, the vertical synchronizing signal is used. By stopping the feeding of the image data, the fields can be matched between the cameras, so that the image is not disturbed even when the video signals displayed on the monitor are switched and displayed.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a power superimposing television camera according to the present invention.

FIG. 2 is a block diagram of another embodiment of a power superimposing type television camera according to the present invention.

[Explanation of symbols]

 1 TV camera 2 Power supply superimposing circuit 3 Sync separation circuit 4 Field detection circuit 5 Exclusive OR circuit 6 Vertical sync signal generation circuit 7 Counter 8 NOT circuit 9 AND circuit 11 TV camera 12 Power supply superposition circuit 13 Sync separation circuit 14 Field detection circuit 15 exclusive OR circuit 18 NOT circuit 19 AND circuit 21 TV camera 22 power supply superimposing circuit 23 sync separation circuit 24 OR circuit 25 sync signal generating circuit 26 timer 27 SR flip-flop circuit 28 AND circuit 31 TV camera 32 power supply Superimposing circuit 33 Synchronous separation circuit 34 OR circuit 36 Timer 37 SR flip-flop circuit 38 AND circuit

Claims (6)

[Claims] 1. A television camera, which superimposes a vertical synchronizing signal on a power source and sends it, and which uses a PLL circuit to generate a synchronizing signal of a video signal synchronized with the vertical synchronizing signal, comprising a reference synchronizing signal generating means. When the field (odd number or even number) of the sync signal sent from the TV camera and the field of the reference sync signal do not match, the sending of the vertical sync signal is stopped to change the field of the sync signal of the TV camera to the reference sync signal. A power superimposition type TV camera characterized by matching with the field. 2. A synchronization signal for a television camera, comprising means for detecting a field (odd or even) of a synchronization signal transmitted from a television camera, means for generating a field for a reference synchronization signal, and means for comparing both fields. The field of the vertical synchronizing signal is stopped when the field of No. 1 and the field of the reference synchronizing signal do not match so that the field of the synchronizing signal of the television camera matches the field of the reference synchronizing signal. The power supply superimposition type television camera described in 1. 3. The power superimposing type television camera according to claim 2, wherein the exclusive OR circuit is used as a comparison means for comparing the field of the synchronizing signal of the television camera with the field of the reference synchronizing signal. 4. A television comprising a phase comparison means for comparing the horizontal synchronizing signal of the horizontal synchronizing signal sent from the television camera and the horizontal synchronizing signal of the reference synchronizing signal, and stopping the sending of the vertical synchronizing signal when the two signals are out of phase with each other. 2. The power superimposing television camera according to claim 1, wherein the field of the synchronization signal of the camera and the field of the reference synchronization signal are matched. 5. A logical sum of a horizontal sync signal pulse sent from a television camera and a horizontal sync signal pulse of a reference sync signal is output, and a timer for outputting the pulse is reset after a certain period of time after reset by the output, and the timer of the timer is reset. 5. The power superimposing type television camera according to claim 4, wherein the vertical synchronizing signal is sent by using an output of an SR flip-flop, which is set by an output pulse and reset by a vertical synchronizing signal, as a gate signal. 6. When the PLL of the television camera is free running, the vertical synchronization signal of the television camera is approximately 2 of the reference synchronization signal.
A double cycle is provided, wherein
The power superimposing television camera according to claim 2, claim 3, claim 4, or claim 5.