JPH0583713A - Cctv monitor system - Google Patents

Abstract

PURPOSE:To send a video signal in time division by connecting plural cameras in cascade in the CCTV monitor system. CONSTITUTION:A synchronized camera 3 and synchronizing cameras 1, 2 each having a video signal changeover switch are connected in cascade by coaxial cables 6, 7, and connected to a monitor 5 through coaxial cable 8 and a camera control unit 4. A code signal to select and control a camera is outputted by the camera control unit 4 to control the changeover switch and a video signal of each camera is selected in a required timing and sent in time division.

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 problems, the present invention solves the above problems by providing synchronized cameras, a plurality of synchronized cameras synchronously coupled to the cameras, and outputting a control signal to select each of the cameras. What is claimed is: 1. A CCTV surveillance system comprising a camera control unit for controlling, and a monitor for displaying captured images, which is connected through the camera control unit, wherein the synchronous camera has a video signal input / output terminal and a control signal. A detection / identification identification unit, a video signal switching unit that is controlled based on the identification result, and a control signal reproduction unit that reproduces the control signal, multiplexes it with the video signal, and outputs the multiplexed signal to the camera in the preceding stage, The synchronized cameras and the synchronized cameras are connected in series, and each camera is based on a control signal from the camera control unit or a control signal from the control signal reproducing unit. Switching the output signal in the video signal switching unit, and configured to transmit time division CCTV
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 switching unit are connected in series, and are connected to a monitor via a coaxial cable and a camera control unit.
When the video signal switching unit is controlled based on the control signal from the camera control unit for selecting and controlling the camera or the control signal from the control signal reproducing unit, and the video signal captured by each camera is switched at a required timing. Divide and transmit.

[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. Reference numeral 4 denotes a camera control unit, which outputs control signals for selecting and controlling each camera and also outputs a video signal from the synchronous camera 1 to the monitor 5. 6, 7 and 8
Is a coaxial cable for transmitting a video signal.

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. A video signal switching unit 23 switches and outputs a video signal. 24 is a video output terminal, which is connected to the subsequent stage with a coaxial cable. 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. A comparison / detection unit 27 compares the phase of the sync signal from the sync separation circuit 25 and the phase of the sync signal from the sync signal generation unit 26 to detect a difference. 28 is a control unit, which is a VCO (Voltage Co
The control unit controls the synchronization timing of the synchronization signal generation unit 26 based on the detection result of the comparison detection unit 27. A pulse generator 29 generates a gate pulse based on the sync signal from the sync signal generator. Reference numeral 30 denotes a detection unit which extracts and detects the control signal multiplexed with the video signal from the camera control unit 4 by the pulse from the pulse generation unit 29. An identification unit 31 identifies the code of the detected control signal and controls the video signal switching unit 23 based on the identification result. Reference numeral 32 denotes a control signal reproducing unit, which again multiplexes the control signal detected by the detecting unit 30 with the video signal and sends the video signal to the preceding camera via the video input terminal 21. Reference numeral 33 denotes a gate, which removes the control signal multiplexed by the control signal reproducing unit 32 and guides the video signal from the preceding camera to the video signal switching unit 23. 34 is a video input terminal of the camera control unit 4, 35 is a control unit main body, and 36 is a video output terminal. A control signal generator 37 multiplexes a control signal for selecting and controlling each 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 (composite video signal), the synchronous camera 2 detects and separates the synchronous signal by the synchronous separating circuit 25, and the comparison detecting unit 27, the control unit 28 and the synchronous signal generating unit 26 synchronize the synchronous signal with the synchronized camera 3. 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.

The control signal generator 34 of the camera control unit 4 outputs control signals for selecting and controlling each 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. Detection unit 30 that received this signal
Detects a control signal superimposed on a predetermined position in the blanking period of the video signal, based on the pulse generated by the pulse generator 29 based on the synchronization signal. On the other hand, the control signal reproducing unit 32
Re-multiplexes the control signal detected by the detection unit 30 with the video signal and sends the video signal to the preceding camera via the video input terminal 21. In this way, the control signal from the camera control unit 4 is sequentially transmitted from the synchronous camera 1 to the cameras in the preceding stage.
Next, the identification unit 31 of the synchronous camera identifies the code of the detected control signal, and controls the video signal switching unit 23 to output the video signal from the camera body 22 when the code matches the preset code, If they do not match, the video signal switching unit 23 is controlled so as to output the video signal of the preceding camera, ie, the video signal from the video input terminal 21. The video signal switching unit 23 controlled in this way is held in that state until the next control signal is input.

Now, for example, when a control code for selecting a video signal picked up by the synchronous camera 1 is sent from the camera control unit, the identification section 31 of the synchronous camera 1 identifies that the set code matches, and By controlling the signal switching unit 23 to select the video signal from the camera body 22, the synchronous camera 1
The video signal captured by is output. At this time, the identification unit 31 of the synchronous camera 2 controls the video signal switching unit 23 so as to identify the code mismatch and select the video signal from the preceding camera. Next, when a control code for selecting the synchronous camera 2 is transmitted, the synchronous camera 2 controls the video signal switching unit 23 so that the video signal from the camera body 22 is output, and the synchronous camera 1 is controlled by the preceding camera. The video signal is switched to output the video signal, and the video signal captured by the synchronous camera 2 is output from the synchronous camera 1. Then, next, when a control code for selecting the synchronized camera 3 is input, the synchronous cameras 1 and 2 are connected so as to identify the mismatch of the codes and select the video signal from the preceding camera, The video signal captured by the synchronized camera 3 is output from the synchronous camera 1.

Although the present embodiment has been described by taking the system composed of two synchronous cameras as an example, the required number of synchronous cameras can be connected. In this case, since the control signals from the control unit 4 are respectively reproduced and multiplexed and sent to the synchronous cameras, a predetermined code is set in advance for each camera, and the corresponding camera is selected by the code of the control signal to perform switching control. can do. Next, the time division time of each camera can be arbitrarily set by the camera control unit 4. In this way, an arbitrary camera can be switched at an arbitrary timing and the time-divided video signal can be taken out from the synchronous camera 1.

[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 video signals of the cameras connected in series 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 synchronized camera, a plurality of synchronized cameras synchronously coupled to the cameras, and a camera control unit for outputting a control signal to select and control each of the cameras.
What is claimed is: 1. A CCTV monitoring system comprising a monitor connected to a camera control unit for displaying a captured image, wherein the synchronous camera has an input / output terminal for a video signal, and an identification section for detecting / identifying a control signal. , A video signal switching unit that is controlled based on the identification result, and a control signal reproducing unit that reproduces the control signal, multiplexes it with the video signal, and outputs the multiplexed video signal to the preceding camera. Each of them is connected in series, and the output signal of each camera is switched by the video signal switching unit based on a control signal from the camera control unit or a control signal from the control signal reproducing unit, and is time-divisionally transmitted. A CCTV surveillance system characterized by the above.