JPH0576006A - CCTV surveillance system - Google Patents

Abstract

(57) [Abstract] [Purpose] A CCTV monitoring system is used to connect multiple cameras in series and transmit video signals in a time division manner. [Structure] The synchronized camera 3 and the synchronous cameras 1 and 2 each having a video signal changeover switch include coaxial cables 6 and 7.
Are connected in series, and are connected to the monitoring monitor 5 via the coaxial cable 8 and the camera control unit 4. The camera control unit 4 outputs a code signal for selecting and controlling the cameras and controls the changeover switch to switch the video signals of the respective cameras at required timings and transmit them in a time division manner.

Description

Detailed Description of the Invention

[0001]

The present invention relates to CCTV (Closed Circu
It television) monitoring system, time-division transmission of video signals.

[0002]

2. Description of the Related Art A schematic configuration diagram of a conventional CCTV monitoring system is shown in FIG. In the figure, 1 and 2 are synchronous cameras,
Reference numeral 3 is a synchronized camera. The synchronous cameras 1 and 2 send signals for synchronization from the synchronized camera 3 to the coaxial cables 10 and 11.
And receives a video signal synchronized with the synchronized camera 3 and outputs the video signal. The video signals obtained by photographing are transmitted from the respective cameras through the coaxial cable 8, and the video signals from the respective cameras are appropriately switched by the switcher 9 and monitored by the monitor 5. In such a method, coaxial cables for transmitting video signals are required for the number of cameras, and a cable for synchronous coupling is also required.If the surveillance area is wide, the installation of coaxial cables becomes a major issue. There was a problem of high cost.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the synchronized cameras and the synchronized cameras are connected in series, and a video signal is time-divisionally transmitted by one coaxial cable. The present invention provides a CCTV monitoring system.

[0004]

In order to solve the above-mentioned problems, the present invention is a CCT in which a plurality of cameras are synchronously coupled.
In the V surveillance system, a synchronized camera, a required number of synchronous cameras connected to the camera and provided with video signal input / output terminals and changeover switches, and a camera control unit for outputting a control signal to select / control the camera And a monitor for displaying captured images, the CCTV being configured to connect the cameras in series and switch the output signal of the camera with the changeover switch based on the control signal, and to transmit in time division. It provides a surveillance system.

[0005]

With the above construction, the CC according to the present invention
In the TV monitoring system, a synchronized camera and a synchronous camera having a video signal changeover switch are connected in series and connected to a monitor via a coaxial cable and a camera control unit. The camera control unit outputs a control signal for selecting and controlling the camera to control the changeover switch,
The video signals captured by each camera are switched and transmitted at a required timing.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A CCTV according to the present invention will be described below with reference to the drawings.
An example of the monitoring system will be described in detail. FIG. 1 is a schematic configuration diagram of a CCTV monitoring system according to the present invention. In the figure, 1 and 2 are synchronous cameras, and 3 is a synchronized camera. A camera control unit 4 outputs a control signal for selecting and controlling the camera and also outputs a video signal from the synchronous camera 1 to the monitor 5. Reference numerals 6, 7 and 8 are coaxial cables for transmitting video signals.

FIG. 2 is a block diagram of the essential parts of one embodiment of the CCTV monitoring system according to the present invention. In the figure, 21 is a video input terminal, which is connected to the preceding camera by a coaxial cable. A camera body 22 is composed of an optical lens, an image sensor, a signal processing circuit, and the like. Reference numeral 23 is a signal selector switch for switching and outputting a video signal. 24 is a video output terminal, and the coaxial cable 6 is used for the synchronous camera 1 in the subsequent stage and the coaxial cable 8 is used.
Is connected to the camera control unit 4. Reference numeral 25 denotes a sync separation circuit, which separates the sync signal from the video signal from the preceding camera and outputs it. Reference numeral 26 is a sync signal generator that outputs a sync signal to the camera body 22. 27 is a comparison / detection unit, which is a sync separation circuit 25
And the phase of the sync signal from the sync signal generator 26 is compared to detect the difference. 28 is a control unit, which is a VCO (Vo
The timing of synchronization of the synchronization signal generator 26 is controlled based on the detection result of the comparison detector 27. Reference numeral 29 denotes a detection unit that detects a control signal from the camera control unit 4. An identification unit 30 identifies the code of the detected control signal and controls the signal changeover switch 23 based on the identification result. Reference numeral 31 is a video input terminal of the camera control unit 4, 32 is a control unit body, and 33 is a video output terminal. A control signal generator 34 multiplexes a control signal for selecting and controlling the camera with the video signal and outputs it.

Next, the operation of the CCTV monitoring system according to the present invention will be described. The video signal from the synchronized camera 3 is transmitted to the synchronous camera 2 by the coaxial cable 7. From this video signal, the synchronous camera 2 detects and separates the sync signal by the sync separation circuit 25, and the comparison detection unit 27, the control unit 28, and the sync signal generation unit 26.
Then, the synchronizing signal synchronized with the synchronized camera 3 is generated to control the camera body 22. Therefore, the synchronous camera 2 generates a video signal synchronized with the synchronized camera 3. Similarly, the synchronous camera 1 receives a video signal from the synchronous camera 2 via the coaxial cable 6, separates the synchronous signal, and generates a video signal synchronized with the synchronous camera 2. In this way, with the synchronized camera 3 as the starting point, the cameras in the subsequent stages are configured to sequentially generate synchronized video signals based on the synchronization signals.

On the other hand, the control signal generator 34 of the camera control unit 4 outputs a control signal for selecting and controlling the camera. This control signal is multiplexed at a predetermined position during the blanking period of the scanning of the video signal and sent to the synchronous camera 1 via the coaxial cable 8. Upon receiving this signal, the detection unit 29 detects the control signal superimposed on the predetermined position in the blanking period of the video signal with reference to the synchronization signal from the synchronization signal generation unit 26. The discriminating unit 30 discriminates the code of this control signal, and controls the signal changeover switch 23 so that the video signal from the camera body 22 is output when the code matches the preset code. Signal, ie video input terminal 21
The change-over switch 23 is controlled so as to output the video signal. The signal changeover switch 23 controlled in this way is held in that state until the next control signal is input.

Explaining in a concrete example, the synchronized camera 3
The video signal captured by is selected and is being output from the synchronous camera 1. At this time, the synchronous cameras 1 and 2
Each of the signal changeover switches 23 is connected so as to output the video signal from the preceding camera, and the control signal from the control signal generator 34 is input to each of the synchronous cameras 1 and 2. Now, when the code for selecting the synchronous camera 2 is input, the signal changeover switch 23 operates so that the synchronous camera 2 outputs the video signal from the camera body 22, and at this time, the synchronous camera 1 displays the image of the camera of the preceding stage. Since it is connected so as to output a signal, the video signal captured by the synchronous camera 2 is output from the synchronous camera 1. Next, when the code for selecting the synchronous camera 1 is input, the synchronous camera 2 is switched to output the video signal of the preceding camera,
The signal changeover switch 23 of the synchronous camera 1 selects the video signal from the camera body 22, and the video signal captured by the synchronous camera 1 is output. Then, next, when a code for selecting the synchronized camera 3 is input, the synchronous camera 1 is switched to output the video signal of the preceding stage, and at this time, the synchronous camera 2
Is connected so as to output the video signal of the preceding camera, that is, the synchronized camera 3, the video signal captured by the synchronized camera 3 is output from the synchronous camera 1.

In this way, the video signals of the synchronized camera 3, the synchronization camera 2, and the synchronization camera 1 are sequentially switched,
It returns to the synchronized camera 3 again. Although the present embodiment has been described by taking a system including two synchronous cameras as an example, the required number of synchronous cameras can be connected. In this case, a predetermined code may be set in advance for each camera, and first, a synchronized camera may be selected as a starting point, or a subsequent camera may be selected as appropriate, and switching may be performed in the order of returning to the synchronized camera again.
Next, the camera switching timing is the camera control unit 4
Can be set arbitrarily. In this way, the video signals obtained by the synchronous cameras 1 and 2 and the synchronized camera 3 are photographed and output from the synchronous camera 1 by time division at a required timing based on the control signal of the camera control unit 4. ..

[0012]

As described above, C according to the present invention
According to the CTV monitoring system, the video signal from the synchronized camera is input to the next-stage synchronous camera via the coaxial cable, and the synchronous camera receiving the signal generates a video signal in synchronization with the video signal, The video signal is selected based on the control signal from the camera control unit and output to the subsequent stage.
In this way, the cameras are connected in series, and the video signals of the respective cameras are switched at required timings and transmitted in time division. Therefore, since the video signal can be transmitted by one coaxial cable, there is an effect that the laying cost of the coaxial cable can be significantly reduced when the monitoring place is remote.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a CCTV monitoring system according to the present invention.

FIG. 2 is a block diagram of essential parts showing an embodiment of a CCTV monitoring system according to the present invention.

FIG. 3 is a schematic configuration diagram of a conventional CCTV monitoring system.

[Explanation of symbols]

 1 Synchronous camera 2 Synchronous camera 3 Synchronized camera 4 Camera control unit 5 Monitor 6 Coaxial cable 7 Coaxial cable 8 Coaxial cable

Claims (1)

[Claims] 1. A CC formed by synchronously connecting a plurality of cameras.
In a TV surveillance system, a synchronized camera, a required number of synchronized cameras connected to the camera and provided with video signal input / output terminals and a changeover switch, and a camera control unit that outputs a control signal to select / control the camera And a monitor that displays the captured video, so that the synchronized camera and the synchronized camera are connected in series, and the output signal of the camera is switched by the changeover switch based on the control signal and transmitted in time division. CC characterized in that
TV monitoring system.