JPH099100A - Camera synchronization method and camera control device in camera monitoring system - Google Patents

Abstract

(57) [Abstract] [Purpose] A camera synchronization system in a camera monitoring system that can synchronize each camera without individually connecting a cable that generates a synchronization signal to multiple cameras. And a camera control device. A terminal side is provided with a plurality of cameras C1 to Cn and camera control devices V1 to Vn, a camera control unit 20 for sending a control signal to a center, and a monitor 21 for displaying video signals of the cameras C1 to Cn. Connect with the coaxial cable 30. The center is provided with a sync signal generator 22 for generating a sync signal. In the center, the synchronization signal of the synchronization signal generator 22 is modulated and sent to the terminal side on the first channel, and the control signal output from the camera control unit 20 is modulated to the terminal side on the second channel. Send out. On the other hand, on the terminal side, the synchronization signal sent from the center is demodulated by each camera control device 2 to be an external synchronization signal for the cameras C1 to Cn. Also, the images picked up by the cameras C1 to Cn are modulated and sent to the center on the third channel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera monitoring system for monitoring a plurality of points by switching and controlling a plurality of monitoring cameras arranged in a monitoring area on the center side so that the cameras are synchronized with each other. The present invention relates to a camera synchronization system and a camera control device that controls each camera.

[0002]

2. Description of the Related Art Conventionally, a video signal from a plurality of surveillance cameras arranged in a surveillance area is transmitted to a TV which is smaller than the number of cameras.
In a camera monitoring system that sequentially switches and displays images on a monitor, if the monitoring cameras are not synchronized, the TV
Since the image on the monitor is disturbed when switching the camera,
In order to synchronize the plurality of cameras provided on the terminal side with each other, for example, in the case of the system shown in FIG. 5, the following synchronization method is used. As shown in FIG. 5, a camera for monitoring is provided on the terminal side, and a CCU (Ca
mera control unit), a switcher 26 for switching connection of signal lines from each camera to the center side, and a monitor 21 for displaying a video image captured by each camera.
In the camera monitoring system equipped with, the synchronization signal generator 22 is installed on the terminal side, and the synchronization signal generator 22 is connected to the CCU of each camera to generate the synchronization signal generated from the synchronization signal generator 22. The signals are used as external synchronization signals of the cameras to synchronize the cameras 1 to 3 with each other.

However, in the case of such a camera monitoring system, since the center side and each camera side are connected by different coaxial cables, a large number of coaxial cables are required, cost is increased, and wiring work is complicated. Therefore, at present, a camera monitoring system of the frequency multiplex transmission system as shown in FIGS. 6 and 7 has been proposed. That is,
The terminal side is provided with a plurality of camera units U1 to Un consisting of cameras C1 to Cn and camera control devices V1 to Vn for controlling them, and the center side is provided with each of the cameras C1 to Cn.
A camera control unit 20 that sends a control signal to Cn and a monitor 2 that displays the images captured by the cameras C1 to Cn.
1, and each of these parts is connected via one coaxial cable 30. Then, a control signal from the camera is sent from the camera control unit 20 on the center side to operate or stop the modulator 4 provided in each of the camera control devices V1 to Vn of the camera units U1 to Un on the terminal side. The video signal from each of the cameras C1 to Cn is switched by modulating the video signal at a frequency different from the frequency at which it is modulated and sending it to the terminal side.

[0004]

However, even in such a frequency multiplex transmission type camera monitoring system, the conventional synchronization system in a system in which the center side and each camera are connected by different coaxial cables, respectively. If it is used, a synchronization signal generator 22 is provided on the terminal side, and the synchronization signal generator 22 is used for each camera control device V1 to Vn or each camera C1 to C.
However, there is a problem in that the cost is increased and the wiring work is complicated because a large amount of coaxial cables must be used. In view of the above-mentioned conventional problems, the present invention relates to a camera synchronization method in a camera monitoring system capable of synchronizing each camera without individually connecting a synchronization signal generator and a plurality of camera control devices with a cable. And a camera control device.

[0005]

In order to solve the problems in the camera synchronization system in such a conventional camera monitoring system, the present invention according to claim 1 has a plurality of cameras on the terminal side and the cameras. A plurality of sets of camera control devices for controlling the camera are provided, and the center side is provided with a camera control unit for sending control signals to the plurality of cameras and a monitor for displaying a video signal sent from each camera. , These terminal-side parts and the center-side parts are connected via a common coaxial cable that constitutes a frequency-multiplexed multi-channel transmission path, and the video signals sent from the plurality of cameras to the center side are switched. A method for synchronizing a camera in a camera monitoring system for displaying on a monitor, comprising a synchronization signal generator for generating a synchronization signal for each camera on a center side. In addition, the synchronization signal generated from this synchronization signal generator is modulated and sent to the terminal side on the first channel, and the video signal is sent from the camera control unit to each camera control device. The control signal output to instruct the stop is modulated and sent to the terminal side on the second channel, and the terminal side demodulates the synchronization signal sent from the center side by each camera control device. The respective cameras are synchronized with each other by using the external synchronization signals of the respective cameras, and the control signals transmitted from the center side are demodulated by the respective camera control devices, and based on the control signals, the respective cameras are controlled. The camera is switched by modulating the video signal from the device and sending it to the center side on the third channel, or by stopping the sending to the center side. It is configured Te.

According to the present invention, the terminal side is provided with a plurality of cameras and a plurality of camera control devices for controlling the cameras, and the center side is provided with control signals to the plurality of cameras. A multi-channel transmission path is provided in which a camera control unit for sending out and a monitor for displaying the video signal sent out from each camera are provided, and these parts on the terminal side and parts on the center side are frequency-multiplexed. A camera synchronization method in a camera monitoring system for connecting via a common coaxial cable, switching video signals to be sent from a plurality of cameras to a center side and displaying the same on the monitor, wherein each of the camera control devices on a terminal side is provided. A synchronization signal extractor for extracting the synchronization signal of the camera from the TV signal broadcast wave or the independent broadcast wave is provided, and the TV signal broadcast wave of the co-listening equipment is provided on the center side. Directly or by modulating the independent broadcast wave and transmitting it to the terminal side on the first channel, and output from the camera control unit to instruct the camera control device to transmit / stop the video signal. The control signal is modulated and sent to the terminal side through the second channel, and at the terminal side, the TV signal broadcast wave or the independent broadcast wave sent from the center side is demodulated by each of the camera control devices and the TV signal is transmitted. The synchronization signal is extracted from the broadcast wave or the independent broadcast wave by the synchronization signal extractor and used as the external synchronization signal of the cameras so that the cameras are synchronized with each other, and the control signal sent from the center side is used as the control signal. Each camera controller demodulates, and based on this control signal, the video signal from each camera is modulated and sent to the center side on the third channel. There is configured as characterized by switching the camera by stopping the transmission to the center side.

Further, in the invention according to claim 3 in the invention according to claim 1 or 2, the control signal transmitted from the camera control unit to each of the camera control devices is the camera. The control command for controlling ON / OFF of the modulator provided in each of the camera control devices for modulating the video signal of (1) and sending it to the center side is included. The present invention according to claim 4 is the control according to the present invention according to any one of claims 1 to 3, wherein each of the camera control devices instructs to send or stop a video signal sent from the camera control unit. When a signal is detected, the vertical sync signal is detected from the sync signal sent from the center side, and the control of sending / stopping the video signal is performed at the time of detecting the vertical sync signal. There is. Moreover, in the present invention according to claim 5, in the invention according to any one of claims 2 to 4, a video signal of a TV signal broadcast wave or an independent broadcast wave demodulated by each camera control device is sent to each camera control device. It is configured to display on a connected terminal monitor.

The present invention according to claim 6 is characterized in that a plurality of cameras provided on the terminal side are connected to the center side through a common coaxial cable forming a frequency-multiplexed multi-channel transmission line, A camera control device in a camera monitoring system for switching video signals sent from a plurality of cameras to a center side and displaying the video on a monitor on the center side, by demodulating a synchronization signal sent from the center side on a first channel. A demodulator for outputting to the camera as an external synchronization signal, an RF modem for demodulating a control signal for instructing sending / stopping of a video signal sent from the center side on the second channel, and a video signal from the camera A modulator that modulates the signal and sends it to the center side on the third channel, and turns on / off the modulator based on the control signal demodulated by the RF modem. It is configured as characterized by comprising a control section for FF control.

Further, the present invention according to claim 7 is characterized in that a plurality of cameras provided on the terminal side are connected to the center side via a common coaxial cable forming a frequency-multiplexed multi-channel transmission line, A camera control device in a camera monitoring system for switching video signals sent from a plurality of cameras to a center side and displaying the video signals on a monitor at the center side.
A demodulator that demodulates a V signal broadcast wave or an independent broadcast wave, and a synchronization signal extractor that extracts a synchronization signal from the TV signal broadcast wave or the independent broadcast wave demodulated by the demodulator and outputs it to the camera as an external synchronization signal , An RF modem that demodulates a control signal for instructing sending / stopping of a video signal sent from the center side on the second channel, and a video signal from each camera that is modulated by the center on the third channel. And a control unit for controlling ON / OFF of the modulator based on the control signal demodulated by the RF modem.

[0010]

Since the present invention is configured as described above, it has the following effects. That is, the sync signal generated from the sync signal generator on the center side is modulated and sent to the terminal side via the coaxial cable. Each camera control device on the terminal side demodulates the transmitted synchronization signal to obtain an external synchronization signal for the camera. Since each camera uses the same synchronizing signal as the external synchronizing signal, the cameras are synchronized with each other. Therefore, it is not necessary to connect the synchronization signal generator to each camera.

The center side modulates the TV signal broadcast wave of the co-listening equipment directly or the independent broadcast wave and sends it to the terminal side via the coaxial cable. Each camera control device on the terminal side demodulates the transmitted TV signal broadcast wave or the independent broadcast wave, and at the same time extracts the synchronization signal from the TV signal broadcast wave or the independent broadcast wave with the synchronization signal extractor to externally synchronize the camera. And Therefore, it is not necessary to provide a synchronizing signal generator or the like.

On the basis of the control signal sent from the center side, the modulator of the camera control device on the terminal side is turned on.
N / OFF control is performed. In the camera control device in which the modulator is OFF-controlled, the video signal from the camera is not sent to the center side. On the other hand, in the camera control device in which the modulator is ON-controlled, the video signal from the camera is sent to the center side. Therefore, the cameras are switched without providing a device for switching.

The ON / OFF control of the modulator is performed when the vertical synchronizing signal in the synchronizing signal sent from the center side is detected. That is, the camera control device which receives the control signal for instructing the transmission of the video signal and the control signal for instructing the stop transmitted from the center side performs ON / OFF control of the modulator in accordance with the vertical synchronization signal. So
The video signal from the beginning of the screen is transmitted. Therefore, the images do not change unnaturally in the middle of the screen.

Further, when the TV signal broadcast wave or the independent broadcast wave of the co-listening facility is used as a synchronization signal, the video signal of the TV signal broadcast wave or the independent broadcast wave is displayed on a terminal monitor connected to each camera control device on the terminal side. It can be displayed and information can be provided to the terminal side by video. Alternatively, in a co-listening facility that receives a TV signal broadcast wave or a self-broadcast wave from the terminal side and displays it on a TV, simply install a camera, a sync signal extractor, etc.
Since the synchronization signal of the V signal broadcast wave or the independent broadcast wave can be used as the synchronization signal of the camera, the camera monitoring system can be configured without newly providing a synchronization signal generator or the like.

Further, in the demodulator of the camera control device on the terminal side, the sync signal sent from the center side on the first channel is demodulated and output to the camera as an external sync signal. A common synchronization signal can be obtained without connecting each camera control device.

Alternatively, the demodulator of the camera control device on the terminal side demodulates the TV signal broadcast wave or the independent broadcast wave transmitted from the center side on the first channel, and the demodulator demodulates the TV signal on the synchronization signal extractor. Since a sync signal is extracted from the signal broadcast wave or the independent broadcast wave and output to the camera as an external sync signal, it is possible to obtain a common sync signal in each camera control device without providing a sync signal generator on the center side. You can

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of this embodiment, and FIG. 3 is a block diagram of the main parts of FIG.
In each of these drawings, in this embodiment, the camera C1 is provided on the terminal side.
To Cn and camera control devices V1 to Vn, a plurality of camera units U1 to Un are provided in the center, a camera control unit 20 and a monitor 21 are provided in the center, and these terminal side parts and center side parts are frequency-multiplexed. It is configured to be connected via a common coaxial cable 30 that constitutes an integrated multi-channel transmission path.

First, the configuration on the terminal side will be described in detail. The camera units U1 to Un on the terminal side have substantially the same configuration. As a typical example, a block diagram of the camera unit U1 is shown in FIG. The camera unit U1 is composed of a camera C1 and a camera control device V1. The camera C1 is installed in the surveillance area to pick up an arbitrary image, and has an external sync signal input terminal for inputting a sync signal from the outside.

The camera control device V1 is an RF (Radio Freq
uency) Modem 3, modulator 4, demodulator 5, address setter 6, and controller 7. The RF modem 3 modulates the signal output from the control unit 7 into a high frequency signal and sends the high frequency signal to the center side via the coaxial cable 30, while demodulating the control signal sent from the center side to the control unit. 7
Output to The modulator 4 modulates the video signal output from the camera C1 and sends it to the center side through the coaxial cable 30. The demodulator 5 demodulates the sync signal sent from the center side and outputs it to the external sync signal input terminal of the camera C1. The address setter 6 is the camera unit U1.
It is for setting a unique address to. Further, the control unit 7 controls each unit in the camera control device V1. The camera control device V1 is capable of controlling a plurality of cameras C1 at the same time by one unit.

Next, the structure of the center will be described in detail. In FIG. 1, the camera control unit 20 includes cameras C1 to C1.
This is for generating and transmitting a control signal for switching Cn. Further, the operator is provided with an operation unit (not shown) for inputting a switching instruction. An RF modem 23 is connected to the camera control unit 20. The RF modem 23 modulates a control signal output from the camera control unit 20 into a high frequency signal and sends the high frequency signal to the terminal side via the coaxial cable 30. , And demodulates the control signal sent from the terminal side and outputs it to the camera control unit 20. The monitor 21 displays a video signal sent from the terminal side. A demodulator 24 is connected to the monitor 21, and the video signal sent from the terminal side is demodulated via the demodulator 24 and output to the monitor 21.

Further, the center is provided with a synchronizing signal generator 22 and a modulator 25. The synchronization signal generator 22 generates a synchronization signal common to the plurality of cameras C1 to Cn on the terminal side and outputs it to the modulator 25. The modulator 25 modulates the synchronizing signal output from the synchronizing signal generator 22 into a high frequency signal and sends it to the terminal side via the coaxial cable 30. Here, the synchronization signal output from the synchronization signal generator 22 is a composite signal composed of a vertical synchronization signal and a horizontal synchronization signal, and all the cameras C1 to Cn are generated by this signal.
It is possible to synchronize the synchronization of.

The coaxial cable 30 connecting the center side and the terminal side configured as described above can transmit frequency-multiplexed signals of at least three channels. The first channel (frequency f1) is a channel for transmitting the sync signal generated by the sync signal generator 22 at the center to the terminal side. The second channel (frequency f2) is a channel for transmitting the control signal generated by the camera control unit 20 at the center to the terminal side. The third channel (frequency f3) is a channel for transmitting the video signals captured by the cameras C1 to Cn on the terminal side to the center side.
If it is necessary to transmit a response signal or the like from the terminal side to the center side in response to the control signal or the like transmitted to the terminal side by the second channel, further set the signal of the fourth channel. , The response signal is transmitted by the fourth channel.

The camera switching operation according to this embodiment will be described below with reference to the flowchart of FIG. 8 showing the operation of the center and the flowchart of FIG. 9 showing the operation of the camera control device. The synchronizing signal constantly output from the synchronizing signal generator 22 at the center is modulated to the frequency f1 by the modulator 25 and sent to the terminal side through the first channel.
This synchronization signal is demodulated by the demodulator 5 provided in the camera control devices V1 to Vn of the camera units U1 to Un on the terminal side, and input to the external synchronization signal input terminals of the cameras C1 to Cn.

At the time of normal operation, each camera control device V from the center to each camera control device V1 to Vn on the terminal side
1 to Vn, that is, the control signals for sequentially switching the video signals from the cameras C1 to Cn are automatically transmitted, and the video displayed on the center monitor 21 is captured by the cameras C1 to Cn. It is automatically switched to the video one by one. That is, as shown in FIG. 8, first, in the camera control unit 20 at the center, initial setting such as calling of the initial memory is performed in each unit (step S1). After the counter (not shown) provided in the center is cleared (step S2), the counter is set to the start state (step S3), and the counter is incremented by one value (step S4).

Subsequently, the camera control unit 20 generates a control signal for the camera unit U1 to which the camera C1 which initially sends the video signal belongs (step S).
5). This control signal is a signal including address data of the camera unit U1 and a control command (a command for ON-controlling the modulator 4 of the camera unit U1). Note that the storage unit (not shown) of the camera control unit 20 stores the address data of each of the camera units U1 to Un in correspondence with the value of the counter, and the camera control unit 20 corresponds to the current counter. The address data is called from its own storage unit to generate a control signal. The control signal thus generated is modulated into a high frequency signal by the modulator 25 and sent to the terminal side via the coaxial cable 30 (step S6).

On the other hand, as shown in FIG. 9, the camera control devices V1 to V of the camera units U1 to Un on the terminal side.
The control unit 7 of n always waits for a signal sent from the center (step S11). Here, when the control signal is input from the center, it is determined whether or not the address data of this control signal matches the address preset in its own address setter 6 (step S12). . If they do not match, step 1
It returns to 1 and becomes a signal waiting state. On the other hand, if the addresses match, then the control command of the control signal is analyzed (step S13), and the content of the control command is executed in the next operation (step S14). Specifically, the camera control device V1 turns on its own modulator 4, modulates the video signal of the camera C1 with the modulator 4, and sends it to the center. This video signal is sent to the center via the coaxial cable 30, demodulated by the demodulator 24 in the center, and displayed on the monitor 21.

Next, as shown in FIG. 8, the center waits until a preset time elapses after sending the control signal (step S7). This is because it is difficult for an observer who is watching the monitor 21 to monitor when the video switching time is too fast, and therefore the switching time is delayed and the video from each of the cameras C1 to Cn is displayed for an appropriate time. After the set time has elapsed, a control signal for the camera unit U1 to which the camera C1 currently transmitting the video signal belongs is generated (step S8). This control signal is a signal including address data of the camera unit U1 and a control command (a command for controlling the modulator 4 of the camera unit U1 to be OFF). The control signal thus generated is modulated into a high frequency signal by the modulator 25 and sent to the terminal side through the coaxial cable 30 (step S).
9).

In each of the camera control devices V1 to Vn on the terminal side which have received this control signal, in the same manner as described above, step S11,
The operation of step S12 is performed. When the camera control device V1 recognizes that the address data of the control signal matches its own address data, step S1
3. The operation of step S14 is performed. That is, the camera control device V1 turns off the modulator 4 of itself and stops the operation of sending the video signal. Further, the center determines whether or not the transmission of the control signal to all the addresses has been completed (step S10). Specifically, when the counter value incremented in step S4 matches the preset counter value (a value equal to the number of all camera control devices V1 to Vn), the transmission to all addresses is completed. to decide. If it is determined in step S10 that the processing has not ended, the operations in steps S4 to S6 are repeated again, and the video signal transmission control to the next camera control device V2 is performed. By this control, the video signal of the camera C2 of the camera control device V2 is displayed on the monitor 21, and the switching from the camera C1 to the camera C2 is completed. By repeating such operations, the camera control device Vn
When the transmission of the control signal to the
It is determined that the transmission of the control signal to all the addresses has been completed in step S1, and the counter is cleared again (step S
2) Then, the control signal is sent again to the camera control device V1.

In such a switching operation, the camera C
The video signal of 1 and the video signal of the camera C2 are both based on the sync signal sent from the sync signal generator 22, and the vertical sync and the horizontal sync are the same. Therefore, the monitor 21 on the center side
The images displayed on the screen can be switched without any disturbance.

In the above description, the case where the images are sequentially and automatically switched during the normal operation has been described.
It may not necessarily be automatic, and the image displayed on the monitor 21 can be switched to the image of an arbitrary camera at an arbitrary timing. For example, as a normal operation, the normal operation is stopped when any one of the cameras C1 to Cn to be switched is instructed via the operation unit of the center during the sequential switching control, and the current video signal is displayed. The camera control device V to which the sending cameras C1 to Cn belong
1 to Vn, a control signal for controlling OFF of the modulator 4 is automatically transmitted, and further, the camera control device V1 to which the cameras C1 to Cn instructed via the operation unit belong.
A control signal for ON-controlling the modulator 4 is automatically sent to Vn. By doing so, it is possible to manually switch to an image from an arbitrary camera at an arbitrary timing. In this case, the image of the switching destination continues to be displayed on the monitor 21 and can be viewed for an arbitrary time until the normal operation is restored or another camera C1 to Cn is instructed via the operation unit. It should be noted that all the switching control may be performed manually by the operation unit of the center.

According to the embodiments described above, the cameras C1 to Cn can be switched without disturbing the image displayed on the monitor 21 of the center. Strictly speaking, however, in the switching operation according to each of the above-described embodiments, if switching is performed in the middle of the screen, it may be unnatural when viewed carefully. In order to solve this problem, in step S13 of FIG. 9, the control unit 7 of the switching source camera control device V1 does not turn off the modulator 4 immediately after the control command analysis, but instead of the center synchronization signal generator 22. The vertical sync signal in the sync signal transmitted from the demodulator 5 is detected from the sync signal output from the demodulator 5, and the modulator 4 is controlled to be turned off when the vertical sync signal is detected. On the other hand, the control unit 7 of the camera control device Vn of the switching destination does not turn on the modulator 4 immediately after analyzing the control command, but also detects the vertical synchronization signal in the synchronization signal from the synchronization signal output from the demodulator 5. The modulator 4 is ON-controlled at the time of detecting the vertical synchronizing signal.

In this way, the switching source camera control device V1
And the switching-destination camera control device Vn both perform the switching operation in synchronization with the detection of the vertical synchronization signal in the synchronization signal, so that the switching-source camera control device V1 has finished transmitting the video signal of one whole screen. At this point, the video signal from the switching destination camera control device Vn can be sent out, and a natural switching operation without a feeling of strangeness can be obtained. Further, according to this method, since there is no time lag in switching between stop and transmission of the video signal from the switching source and switching destination camera control devices, it is possible to prevent the screen from being disturbed at the time of switching.

In the above description, the control signal sent from the camera control unit 20 at the center to the terminal side turns on the modulator 4 of each of the camera control devices V1 to Vn.
However, the control signal does not necessarily have to be such a signal, and each camera control device V
Any content can be used as long as it can instruct 1 to Vn to send / stop the video signals of the cameras C1 to Cn controlled by itself. Therefore, for example, the power sources of the cameras C1 to Cn are turned on.
It may be a control signal to turn on / off, or each modulator 4
A control signal for turning on / off the connection device such as an RF switch may be provided between the connection cable and the coaxial cable 30.

Still another embodiment will be described with reference to FIGS. Structures not particularly described are the same as those in the first embodiment described above. First, the configuration of this embodiment will be described. In this embodiment, a co-listening facility 1 including a video deck 11 and a modulator 12 for performing independent broadcasting as existing facilities.
0 is set. In this co-listening facility 10, the video signal of the video deck 11 is modulated into a high frequency signal by the modulator 12 and is broadcast as an independent broadcast wave. In this case, since the video signal sent from the video deck 11 becomes a sync signal, a separate sync signal generator need not be provided.

The center is provided with an antenna 26 for receiving the TV signal broadcast wave and transmitting it to the terminal side via the coaxial cable 30. In this case, since the TV signal broadcast wave received by the antenna 26 becomes a synchronizing signal, the synchronizing signal generator 22 and the modulator 25 shown in FIG. 1 are not provided. On the other hand, each camera unit U on the terminal side
1 to Un camera control devices V1 to Vn include a demodulator 13 for demodulating a TV signal broadcast wave or an independent broadcast wave sent from the center, and a TV signal broadcast wave or an independent broadcast wave demodulated by the demodulator 13. There is provided a sync signal extractor 8 for extracting the sync signal of the camera from.

Next, the synchronizing operation according to this embodiment will be described. First, the independent broadcast wave transmitted by the co-listening facility 10 or the TV signal broadcast wave received by the antenna 26 is transmitted to the terminal side on the first channel via the coaxial cable 30. In the case of the TV signal broadcast wave received by the antenna 26, it is transmitted on the channel of the TV signal broadcast wave. On the terminal side, the demodulator 13 demodulates the TV signal broadcast wave, and the sync signal extractor 8 extracts the sync signal from the TV signal broadcast wave. This sync signal is input as an external sync signal of the camera 1. In this way, the existing co-listening equipment 10
Since the cameras C1 to Cn are synchronized with each other by using the TV signal broadcast wave or the independent broadcast wave broadcast by, the video signals from the cameras can be switched without disturbing the video. In particular, according to the present embodiment, since the synchronizing signal generator 22 and the synchronizing modulator 25 are not required, the cost can be further reduced.

Each of the camera control devices V1 to Vn has a TV demodulated by the demodulator 13 as shown in FIGS.
A terminal monitor 9 that displays a video signal of a signal broadcast wave or an independent broadcast wave may be provided. Since the video signal of the independent broadcast wave can be displayed on the terminal side by providing the terminal monitor 9, various kinds of guidance information and the like can be used. For example, in the event of an abnormality such as a fire, evacuation information can be sent from the center and displayed on the terminal side.

[0038]

As described above, the present invention according to claim 1 is provided with the synchronizing signal generator on the center side, sends the synchronizing signal to the terminal side on the first channel, and sends the control signal. It is sent to the terminal side on the second channel, and the terminal side synchronizes the cameras with each other by using the synchronizing signal as the external synchronizing signal of each camera, and based on the control signal sent from the center side. By switching the camera by sending / stopping the video signal from the camera to the center side on the third channel and switching the camera, the synchronization of each camera can be synchronized by the synchronization signal sent via the coaxial cable. Sometimes, the disturbance of the image on the monitor can be eliminated. Further, since it is not necessary to connect each camera to the synchronization signal generator, it is not necessary to add many cables, and there is an effect that the cost can be significantly reduced.

The present invention according to claim 2 is further provided with a sync signal extractor for extracting a sync signal from the TV signal broadcast wave or the independent broadcast wave on the terminal side, and the TV signal broadcast wave or the independent broadcast wave on the center side. Is transmitted to the terminal side on the first channel, and the control signal is transmitted to the terminal side on the second channel, and the terminal side transmits the synchronization signal from the TV signal broadcast wave or the independent broadcast wave by the synchronization signal extractor. Synchronize with each other by extracting and using as external sync signal of the camera, and send video signal from each camera to the center side by the third channel based on the control signal sent from the center side.・ By stopping and switching the cameras, the synchronization signals sent via the coaxial cable can synchronize the cameras with each other, thus disturbing the monitor image. It is possible to switch the Ku camera.
Further, there is an effect that a large number of cables need not be added and the cost can be significantly reduced.

Further, in the present invention according to claim 2, the terminal side is provided with a sync signal extractor for extracting a sync signal from the TV signal broadcast wave or the independent broadcast wave, and the synchronization is performed from the TV signal broadcast wave or the independent broadcast wave. Synchronizing each camera by using the TV signal broadcast wave broadcast by the existing co-listening equipment by synchronizing each camera by extracting the synchronization signal with the signal extractor and using it as the external synchronization signal of the camera. Can be adjusted, and the synchronizing signal generator and the like can be omitted, so that the cost can be further reduced.

Further, according to the present invention, the control signal sent from the camera control unit is a modulator provided in each camera control device for modulating the video signal of the camera and sending it to the center side. By including a control command for ON / OFF control, it is possible to control the sending / stopping of the camera image by ON / OFF controlling the modulator of the camera control device on the terminal side, and to provide a special switching device. Since the cameras can be switched without providing them, the cost can be further reduced.

Further, according to the present invention as set forth in claim 4, when each camera control device detects a control signal for instructing transmission / stop of the video signal transmitted from the camera control unit, the camera control device transmits from the center side. By detecting the vertical sync signal from the sent sync signal and controlling the sending / stopping of the video signal in accordance with the detection of the vertical sync signal, the video can be switched most naturally.

Furthermore, the present invention according to claim 5 is characterized in that a video signal of a TV signal broadcast wave or an independent broadcast wave demodulated by each camera control device is displayed on a terminal monitor connected to each camera control device, and When the signal broadcast wave is used as a synchronization signal, the video can be displayed on a terminal monitor provided in each camera control device on the terminal side, and information can be provided to the terminal side by video. Alternatively, in the co-listening equipment that receives the TV signal broadcast wave from the terminal side and displays it on the TV, the synchronization signal extracted from the TV signal broadcast wave can be obtained only by installing a camera, a sync signal extractor or the like on the terminal side. Can be used as a camera synchronization signal, and a camera monitoring system capable of synchronization can be configured without newly providing a synchronization signal generator or the like.

Further, in the present invention according to claim 6, the camera control device includes a demodulator that demodulates the transmitted synchronization signal, and an RF modem that demodulates the transmitted control signal.
By including a modulator that modulates a video signal from the camera and a control unit that controls ON / OFF of the modulator based on the demodulated control signal, the demodulator demodulates the synchronization signal that is sent and the camera is demodulated. Since it can be sent as an external synchronization signal to the camera control device, it is possible to configure a camera control device that can obtain a common synchronization signal without individually connecting the synchronization signal generators.

Further, in the present invention according to claim 7, the camera control device extracts a synchronizing signal from the demodulator for demodulating the transmitted TV signal broadcast wave or the independent broadcast wave, and the demodulated TV signal broadcast wave or the like. A synchronizing signal extractor, an RF modem for demodulating a transmitted control signal, a modulator for modulating a video signal from a camera, and a control unit for ON / OFF controlling the modulator based on the demodulated control signal. Since the TV signal broadcast wave is demodulated by the demodulator and the sync signal is extracted by the sync signal extractor, the sync signal can be obtained even if the sync signal generator is not provided on the center side or the terminal side. It is possible to configure a camera control device capable of

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of the present invention.

FIG. 2 is a block diagram showing an overall configuration in the case where co-listening equipment and the like are provided.

FIG. 3 is a block diagram of the camera unit in FIG.

FIG. 4 is a block diagram of the camera unit of FIG.

FIG. 5 is a block diagram showing an overall configuration of a conventional camera switching system.

FIG. 6 is a block diagram showing an overall configuration of a conventional multiplex transmission system.

FIG. 7 is an enlarged view of a main part of FIG. 6;

FIG. 8 is a flowchart on the center side.

FIG. 9 is a flowchart on the terminal side.

[Explanation of symbols]

 U1 to Un camera unit V1 to Vn camera control device C1 to Cn camera 3,23 RF modem 4,12,25 modulator 5,13,24 demodulator 6 address setter 7 controller 8 synchronization signal extractor 9 terminal monitor 10 Common listening equipment 11 VCR 20 Camera control unit 21 Monitor 22 Synchronous signal generator 26 Antenna 30 Coaxial cable

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kenichi Horibata 2-1043 Kamiosaki, Shinagawa-ku, Tokyo Hochiki Co., Ltd. (72) Keigo Takeuchi 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Kazuhiro Sato 1-32 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Yoshito Bando 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. Within

Claims (7)

[Claims] 1. A terminal side is provided with a plurality of sets of a plurality of cameras and a camera control device for controlling the cameras, and a center side is provided with a camera control unit for sending a control signal to the plurality of cameras and each camera. Equipped with a monitor for displaying the video signal sent from, connecting each part on the terminal side and each part on the center side through a common coaxial cable forming a frequency-multiplexed multi-channel transmission path, A camera synchronization method in a camera monitoring system for switching video signals to be sent from a plurality of cameras to a center side and displaying the same on a monitor, the method including a sync signal generator for generating a sync signal for each camera on the center side. , The synchronization signal generated from this synchronization signal generator is modulated and sent to the terminal side on the first channel, and The control signal output to instruct each of the camera control devices to send and stop the video signal is modulated and sent to the terminal side on the second channel, and sent from the center side on the terminal side. The camera control devices demodulate the synchronization signals to obtain the external synchronization signals of the cameras so that the cameras are synchronized with each other, and the control signals sent from the center side are transmitted to the camera control devices. The camera is switched by demodulating and modulating the video signal from each camera based on the control signal and sending the video signal to the center side on the third channel or by stopping the sending to the center side. Method for synchronizing cameras in a camera monitoring system. 2. A terminal side is provided with a plurality of sets of cameras and a camera control device for controlling the cameras, and a center side is provided with a camera control unit for sending control signals to the plurality of cameras and each camera. Equipped with a monitor for displaying the video signal sent from, connecting each part on the terminal side and each part on the center side through a common coaxial cable forming a frequency-multiplexed multi-channel transmission path, A camera synchronization method in a camera monitoring system for switching video signals to be sent from a plurality of cameras to a center side and displaying them on the monitor, wherein each of the camera control devices on the terminal side is switched from a TV signal broadcast wave or an independent broadcast wave to Equipped with a sync signal extractor for extracting the sync signal of the camera, the center side directly modulates the TV signal broadcast wave of the co-listening equipment or the independent broadcast wave. The second control circuit modulates a control signal that is sent to the terminal side on the first channel and that is output from the camera control unit to instruct the camera control devices to send and stop the video signal. The signal is sent to the terminal side through a channel, and on the terminal side, the TV signal broadcast wave or the independent broadcast wave sent from the center side is demodulated by each of the camera control devices, and the synchronization is performed from the TV signal broadcast wave or the independent broadcast wave. By synchronizing the respective cameras by extracting the synchronizing signal by the signal extractor and using it as the external synchronizing signal of the camera, and demodulating the control signal sent from the center side by the respective camera control devices, Based on the control signal, the video signal from each camera is modulated and sent to the center side on the third channel, or the sending to the center side is stopped. Camera synchronization method in a camera surveillance system and switches the camera by. 3. The control signal sent from the camera control unit to each camera control device is a modulation provided in each camera control device for modulating a video signal of the camera and sending the modulated video signal to a center side. The camera synchronization method in the camera monitoring system according to claim 1 or 2, further comprising a control command for controlling ON / OFF of the device. 4. The vertical synchronization signal from the synchronization signal transmitted from the center side when each of the camera control devices detects a control signal for instructing transmission / stop of a video signal transmitted from the camera control unit. Is detected,
The video signal is sent when the vertical sync signal is detected.
The control according to any one of claims 1 to 3, wherein stop control is performed.
A method for synchronizing cameras in the camera monitoring system according to. 5. The T demodulated by each of the camera control devices
5. The camera synchronization method in the camera monitoring system according to claim 2, wherein the video signal of the V signal broadcast wave or the independent broadcast wave is displayed on a terminal monitor connected to each camera control device. 6. An image transmitted from a plurality of cameras provided on a terminal side to a center side via a common coaxial cable forming a frequency-multiplexed multi-channel transmission line, and sent from the plurality of cameras to the center side. A camera control device in a camera monitoring system for switching a signal and displaying it on a monitor on the center side, which demodulates a synchronization signal sent from the center side on a first channel and outputs it to the camera as an external synchronization signal. And the RF modem that demodulates the control signal for instructing the sending / stopping of the video signal sent from the center side on the second channel, and the video signal from the camera is modulated on the third channel. A modulator for sending to the center side and a control unit for controlling ON / OFF of the modulator based on a control signal demodulated by the RF modem are provided. The camera control device in a camera surveillance system according to claim. 7. An image transmitted from a plurality of cameras provided on the terminal side to the center side via a common coaxial cable forming a frequency-multiplexed multi-channel transmission line, and sent from the plurality of cameras to the center side. A camera control device in a camera monitoring system that switches a signal and displays it on a monitor on the center side, the demodulator for demodulating a TV signal broadcast wave or an independent broadcast wave transmitted from the center side on a first channel, A sync signal extractor for extracting a sync signal from the TV signal broadcast wave or the independent broadcast wave demodulated by the demodulator and outputting it to the camera as an external sync signal, and a video signal sent from the center side on the second channel. An RF modem that demodulates the control signal for instructing sending / stopping, and the video signal from each camera is modulated and sent to the center side on the third channel. That a modulator, a camera control device in a camera surveillance system, characterized by comprising a control section for ON / OFF controlling the modulator based on the demodulated control signal with the RF modem.