JP2966747B2 - Video surveillance system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video surveillance system using, for example, a broadband LAN system.

[0002]

2. Description of the Related Art As a conventional video monitoring system, FIG.
And those using the broadband LAN system shown in FIG. 7 and those using the baseband system shown in FIG. In the video surveillance system using the broadband LAN system shown in FIG.
The monitoring video signal photographed by the camera room d, for example, is transmitted through the coaxial cables 72a to 72d.
The signals are input to modulators 74a to 74d installed in an S (Electric Pipe Space) 73. The EPS 73 is:
For example, in a building or the like, it is an operation room where connection parts for electric cables, adjustment valves for pipes and the like are installed.

The modulators 74a to 74d are for frequency-multiplexing and transmitting a video signal, and are configured as shown in FIG. That is, the video signal input from the video input terminal 741 is modulated by the IF modulator 742 into a high-frequency signal having an intermediate frequency, and
Is input to The IF converter circuit 743 converts the intermediate frequency into an arbitrary frequency, suppresses the level of noise such as spurious components outside the band by a band-pass filter circuit 744, and outputs the signal from a high-frequency output terminal 745.

[0004] The modulated output output from each of the high-frequency output terminals 745 of the modulators 74a to 74d is output to the main coaxial cable 76 via the splitters 75a to 75d, frequency-multiplexed and transmitted to the monitoring room 80. Is done.

The monitor room 80 is provided with a demodulator 81, a controller 82, and a monitor TV 83. The demodulator 81 demodulates a monitor video signal of a channel selected by the controller 82 and displays the demodulated video signal on the monitor TV 83.
That is, by operating the controller 82, the video signals captured by the monitoring cameras 71a to 71d are arbitrarily selected and displayed on the monitor TV 83 for monitoring.

In the video surveillance system using the baseband system shown in FIG. 8, a plurality of surveillance cameras 71a to 71a are provided.
1d is sent to, for example, the EPS 73 via the coaxial cables 72a to 72d, respectively.
The data is transmitted to the monitoring room 80 via a to d.

The monitoring room 80 has an AV switcher 8
4, a controller 82 and a monitor TV 83 are provided, and the AV switcher 84 includes main trunk coaxial cables 76a to 76a.
The monitor video signal transmitted by 76d is selected by the instruction of the controller 82, and is displayed on the monitor TV 83 for monitoring.

[0008]

In the video surveillance system using the conventional broadband LAN system shown in FIG. 7, a modulator for frequency-multiplexing and transmitting video signals output from the monitoring cameras 71a to 71d. 74a-74
d is installed in the EPS 73. Therefore, each camera 7
1a to 71d to the EPS 73, each camera 71
One coaxial cable 72a to 72d for each of a to 71d
And a radial network must be formed for each floor. In the EPS 73, a modulator 74a corresponding to each of the cameras 71a to 71d is provided.
Since ~ 74d is installed, a large installation space is required.

In the conventional video surveillance system using the baseband system shown in FIG. 8, one camera is provided between the cameras 71a to 71d and the EPS 73 in the same manner as in FIG. Coaxial cable 72 for each
a-72d must be laid, and EPS7
3 to the monitoring room 80, each monitoring camera 7
One trunk coaxial cable 76a-for each 1a-71d
76d must be laid.

The present invention has been made in view of the above circumstances, and can reduce the size of equipment installed in an EPS or the like.
It is an object of the present invention to provide a video surveillance system that can simplify the installation of a coaxial cable.

[0011]

SUMMARY OF THE INVENTION The present invention provides a plurality of surveillance cameras including means for photographing a surveillance area, and IF modulation means for modulating a video signal output from the means to an intermediate frequency signal of a predetermined channel. A plurality of coaxial cables for frequency-multiplexing and transmitting the intermediate frequency signals output from these surveillance cameras for each block, and one of a plurality of intermediate frequency signals for frequency-multiplexing and transmission by each of the coaxial cables. A plurality of IF converters for extracting channel signals and converting the signals to frequencies of different channels, a main coaxial cable for frequency-multiplexing the output of these IF converters and transmitting the multiplexed signals to a monitoring room; A controller for outputting a channel selection control signal to the converter.

[0012]

When an instruction for selecting a specific surveillance camera is input to the controller, the controller inputs a control signal for selecting a channel of the camera selected based on the input instruction to each IF converter via the main coaxial cable. . As a result, each IF converter converts the intermediate frequency signal of the designated channel from the intermediate frequency signals of a plurality of channels output from the surveillance camera to different channels, and transmits the converted signal to the monitoring room via the main coaxial cable. In the monitoring room, the high-frequency video signal transmitted by the main coaxial cable is selected under the control of the controller, demodulated, and displayed on a monitor screen.

As described above, each surveillance camera incorporates an IF modulation means, and an IF converter for converting an intermediate frequency signal from the surveillance camera into a high-frequency video signal of another channel is provided in the EPS or the like. The coaxial cable for transmitting the intermediate frequency signal output from the camera need only be provided for each block, and a video surveillance system can be constructed using one trunk coaxial cable.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system block diagram showing a basic configuration example of a video monitoring system using, for example, a broadband LAN system.

As shown in FIG. 1, a plurality of monitoring cameras 1a and 1b are installed at a monitoring place. This surveillance camera 1a,
1b is an imaging lens 11, as schematically shown in FIG.
It comprises a video signal converter 12, an IF modulator 13, and an intermediate frequency output terminal 14, and the IF modulator 13 has the same function as the IF modulator 742 in the modulator shown in FIG. The surrounding scenery captured by the lens 11 is converted into an electrical signal as a video signal by a video signal converter 12, input to an IF modulator 13, and output to an intermediate frequency output terminal 14.
Thus, the signal is output as an intermediate frequency signal. In this case, for example, the surveillance camera 1a outputs an intermediate frequency signal of channel A (ch.A), and the surveillance camera 1b outputs an intermediate frequency signal of channel B (ch.B).

The intermediate frequency signals of channels A and B output from the monitoring cameras 1a and 1b are CATV signals.
Output to the coaxial cable 3 from the 1-branch splitters 2a and 2b for frequency division multiplexing and IF (intermediate frequency) in the EPS 4.
Input to converter 5. This IF converter 5
The IF converter circuit 743 and the band-pass filter circuit 744 in the modulator shown in FIG. 7 are integrated into one unit, and the signal of the channel A or the channel B is transmitted according to a control signal sent from a monitoring room described later. Select and convert to any channel C, 1 for CATV
The signal is transmitted from the branch unit 6 to the monitoring room via the main coaxial cable 7. In the monitoring room, the video signal of channel C sent from the IF converter 5 via the main coaxial cable 7 is demodulated and displayed on a monitor TV for monitoring.

As described above, according to the present invention, the conventional modulator is divided into two parts, and the IF modulator 742 at the preceding stage is connected to the monitoring cameras 1a and 1a.
1b, and the IF converter circuit 743 and the band-pass filter circuit 744 at the subsequent stage are integrated into one unit.
It is a separate unit from the surveillance camera side for installation in S4, machine room, etc.

FIG. 3 is a block diagram showing a schematic configuration of the IF inverter 5. The intermediate frequency signals output from the monitoring cameras 1a and 1b of FIG. 1 are transmitted by the coaxial cable 3, input from the intermediate frequency input terminal 21, amplified by the intermediate frequency amplifier 22, and input to the mixer diode 23. . On the other hand, the signal output from the local oscillator 24 is also input to the mixer diode 23. The mixer diode 23 converts the intermediate frequency signal input from the intermediate frequency amplifier 22 into a desired high frequency signal and inputs the signal to the output signal amplifier 25. The high-frequency signal amplified by the output signal amplifying unit 25 is output from the high-frequency output terminal 27 after the level of noise such as spurious components outside the band is suppressed by the band-pass filter circuit 26.

Further, the high-frequency control signal input from the control signal input terminal 28 is input to the RF modem 29 and controls the frequency of the signal output from the local oscillator 24.
At this time, when intermediate frequency signals of a plurality of different frequencies are input from the intermediate frequency input terminal 21, the local oscillator 2
By changing the frequency of No. 4, one of the plurality of intermediate frequency signals can be selected and output from the high frequency output terminal 27 as a high frequency signal of any desired frequency. This makes it possible to have a scanning function similar to that of an AV switcher in a conventional video surveillance system generally installed.

The high-frequency control signal input from the control signal input terminal 28 is input to the RF modem 29 to control the power supply unit 30 so as to perform ON / OFF control of the service outlet 31. Thereby, the power supply control of the peripheral devices of the apparatus can be remotely controlled from the monitoring room 60 or the like.

When this apparatus is used as a part of a dual cable broadband LAN, the high-frequency output terminal 27 is connected to the upstream trunk and the control signal input terminal 28 is connected to the downstream trunk. When used as part of a broadband LAN, the high-frequency output terminal 27 is also connected to the trunk line as a control signal input terminal, and nothing is connected to the control signal input terminal 28. Can be done.

Next, the overall operation of the above embodiment will be described.
The surveillance camera 1a shown in FIG. 1 outputs a video signal at the intermediate frequency of channel A, and the surveillance camera 1b simultaneously outputs a video signal at the intermediate frequency of channel B.
Each of the video signals is frequency-multiplexed from the splitters 2a and 2b to the coaxial cable 3 and transmitted, and is input to the IF converter 5 installed in the EPS 4. The IF converter 5 selects the signal of the channel A or the channel B according to a control signal sent from the monitoring room, converts the signal into a high frequency signal of the channel C, and outputs the signal from the branching unit 6 through the trunk coaxial cable 7. To be transmitted.

FIG. 4 is a spectrum diagram showing the operation of the IF converter 5. The spectrums 40 and 41 are video signals modulated at the intermediate frequencies of channel A and channel B input from the coaxial cable 3 to the IF converter 5. The spectrum 42 is a video signal in which the spectrum 40 or 41 is frequency-converted by the IF converter 5 and is output toward the trunk coaxial cable 7. The frequency of this spectrum is assumed to be channel C.

Now, when a command is issued from the monitoring room or the like via the RF modem 29 to oscillate the frequency fL1 of the spectrum 43 of FIG. 4 from the local oscillator 24 of FIG. 3, the spectrum 40 of the channel A is frequency-converted. And is output as the spectrum 42 of the channel C. Thus, the surveillance camera 1 shown in FIG.
a video signal is output. Similarly, when the frequency fL2 of the spectrum 44 is oscillated from the local oscillator 24, the video signal of the monitoring camera 1b of FIG.

Here, the signal output from the IF converter 5 of FIG. 1 to the main coaxial cable 7 is filtered by the band-pass filter 26 of FIG. Only the spectrum 42 is output.

FIG. 5 shows an example of a system configuration in which a plurality of monitoring cameras are divided into two blocks and two converters 5a and 5b are installed. That is, the surveillance cameras 1a and 1b in the first block
A video signal of the intermediate frequency of B is output, and the splitters 2a and 2
b to the coaxial cable 3, frequency-multiplexed and transmitted, and the IF converter 5 installed in the EPS 4.
is input to a. This IF converter 5a is connected to the monitoring room 6
According to the control signal from 0, either the signal of channel A or the signal of channel B is selected, the frequency is converted to channel C, and input to the trunk coaxial cable 7 from the splitter 6a.

The surveillance cameras 1c, 1 in the second block
d outputs a video signal of an intermediate frequency of channels A and B, is input to the coaxial cable 3 from the splitters 2c and 2d, is frequency-multiplexed and transmitted, and is input to the IF converter 5b installed in the EPS 4. Is done. The IF converter 5b selects either the channel A or the channel B according to the control signal from the monitoring room 60, converts the frequency to the channel D, and inputs the converted signal to the trunk coaxial cable 7 from the branching device 6b.

The high-frequency video signals of channels C and D output from the IF converters 5a and 5b are frequency-multiplexed by the main coaxial cable 7 and are monitored.
Transmitted to The high-frequency video signal transmitted to the monitoring room 60 is split by the splitter 61 and input to the controller 62 and the demodulator 63. The demodulator 63 selects and demodulates a high-frequency video signal of a designated channel according to an instruction from the controller 62, and outputs the demodulated video signal to the monitor TV 64.

In the above configuration, the monitor TV 64
When an image of the surveillance camera 1a is to be displayed on the screen of the controller 62, an instruction to select the surveillance camera 1a is issued by the controller 62.
To enter. The controller 62 inputs a control signal for selecting the channel A based on the input instruction to the IF converters 5a and 5b via the trunk coaxial cable 7. Thereby, the IF converter 5a converts the video signal of channel A output from the surveillance camera 1a to channel C, and outputs it to the trunk coaxial cable 7 via the splitter 6a. The IF converter 5b converts the video signal of channel A output from the surveillance camera 1c to channel D, and outputs the converted signal to the trunk coaxial cable 7 via the splitter 6b. The main coaxial cable 7 frequency-multiplexes the high-frequency video signals of the channels C and D and transmits them to the monitoring room 60.

When an instruction to select the surveillance camera 1a is input, the controller 62
Is output to the demodulator 63. In response, the demodulator 63 receives the high-frequency video signal from the surveillance camera 1a output as the channel C from the IF converter 5a, demodulates it, and displays it on the screen of the monitor TV64.

When an instruction to select the monitoring camera 1c is input to the controller 62,
Inputs a control signal for selecting channel A to the IF converters 5a and 5b via the main coaxial cable 7, and outputs a control signal for receiving channel D to the demodulator 63. In response, the demodulator 63 sets the IF converter 5
a, receives a high-frequency video signal output from the surveillance camera 1c as a channel D, demodulates it, and
Projected on the screen.

By operating the controller 62 as described above, all video signals of the monitoring cameras 1a to 1d can be switched to the monitor TV 64 and displayed. In FIG. 5, the video signals captured by the monitoring cameras 1a and 1c are both modulated into high-frequency video signals of channel A by the modulators 2a and 2c and output, and are also captured by the monitoring cameras 1b and 1d. The modulated video signals are both modulated into high-frequency video signals of channel B by the modulators 2b and 2d, and are respectively frequency-multiplexed and transmitted by the coaxial cables 3a and 3b. The coaxial cables 3a and 3b And the IF converters 5a and 5b, there is no mutual interference between the coaxial cables 3a and 3b.

[0033]

As described above in detail, according to the present invention, each surveillance camera incorporates an IF modulator, converts a photographed video signal into an intermediate frequency signal of an arbitrary channel, and performs frequency multiplexing with a coaxial cable. IF transmitted and installed in EPS etc.
A high-frequency video signal of another channel is converted by a converter and transmitted to a monitoring room or the like by a main coaxial cable. Therefore, an arbitrary monitoring camera can be selected by an IF converter and channel conversion can be performed. The coaxial cable for transmitting the output intermediate frequency signal only needs to be provided for each block, and a video surveillance system can be constructed using one trunk coaxial cable. Further, since there is no need to install a modulator in the EPS or the like, the equipment in the EPS can be reduced in size and the construction can be simplified.

In the above embodiment, the broadband L
Although the case where the AN method is used has been described, the present invention is not limited to this, and it is needless to say that the present invention can be implemented even when another method is used.

[Brief description of the drawings]

FIG. 1 is a basic system configuration diagram showing a video monitoring system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of the monitoring camera in the embodiment.

FIG. 3 is a block diagram showing a configuration of an IF converter in the embodiment.

FIG. 4 is a spectrum chart showing the operation of the IF converter in the embodiment.

FIG. 5 is a block diagram showing a system configuration example of the present invention.

FIG. 6 is a configuration diagram of a conventional video monitoring system based on a broadband LAN system.

FIG. 7 is a block diagram showing an outline of the modulator in FIG. 6;

FIG. 8 is a configuration diagram of a conventional video monitoring system based on a baseband system.

[Explanation of symbols]

 Reference Signs List 1, 1a-1d surveillance camera 2, 2a-2d branch unit 3, 3a, 3b coaxial cable 4 EPS (Electric Pipe Space) 5, 5a, 5b IF converter 6, 6a, 6b branch unit 7 trunk coaxial cable 60 monitoring room 61 Branch device 62 Controller 63 Demodulator 64 Monitor TV

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Michinori Shiga 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi Antenna Co., Ltd. Omiya Plant (56) References JP-A-63-59086 (JP, A)

Claims (2)

(57) [Claims] 1. A plurality of surveillance cameras comprising: means for photographing a surveillance area; and IF modulation means for modulating a video signal output from the means to an intermediate frequency signal of a predetermined channel.
A coaxial cable for frequency-multiplexing and transmitting an intermediate frequency signal output from these surveillance cameras, and a signal of one channel out of a plurality of intermediate frequency signals transmitted by the coaxial cable and extracting the signal for another channel. A video surveillance system, comprising: an IF converter for converting and transmitting the converted signal to a monitoring room; and a controller provided in the monitoring room and outputting a channel selection control signal to the IF converter. 2. A plurality of surveillance cameras comprising: means for photographing a surveillance area; and IF modulation means for modulating a video signal output from the means to an intermediate frequency signal of a predetermined channel.
A plurality of coaxial cables for frequency-multiplexing and transmitting the intermediate frequency signals output from these surveillance cameras for each block, and one of a plurality of intermediate frequency signals for frequency-multiplexing and transmission by each of the coaxial cables.
A plurality of IF converters for extracting channel signals and converting the signals to frequencies of different channels, a main coaxial cable for frequency-multiplexing the output of these IF converters and transmitting the multiplexed signals to a monitoring room; A video surveillance system, comprising: a controller that outputs a channel selection control signal to a converter.