JPH1169340A - Video transfer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect together plural TV cameras via a small number of wirings for the simplification and the reduction of installation cost of the wiring facilities by sharing a synchronizing signal generation device by plural TV cameras to make all these cameras perform the photographing synchronously with each other and transmitting a control signal to true adapter that is connected to a desired TV camera. SOLUTION: The TV cameras 11 to 1n operate synchronously with the synchronizing signals produced by a synchronizing signal generation device 6. These synchronizing signals are supplied to the cameras 11 to 1n via the adapters 91 to 9n . Every TV camera 11 generates a fly-back period while the cameras 11 to 1n are performing the photographing synchronously with the synchronizing signals of the device 6. A control signal generation device 7 transmits the control signals to the cameras 11 to 1n by making use of the said fly-back period. Therefore, a switch 14 of a desired adapter 9i is closed and the video signals equivalent to a single frame are sent to a coaxial cable 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an apparatus for monitoring using a plurality of television cameras. In particular, the present invention relates to a technique for connecting a plurality of television cameras with a small number of wires.

[0002]

2. Description of the Related Art In order to prevent theft in stores and department stores, a television camera is arranged in a store and monitored. In a large-scale store, the number of television cameras to be arranged is large, and the images of the plurality of television cameras are intensively monitored at one place such as a security room.

[0003] This conventional example will be described with reference to FIGS. 13 and 14. Figure 13 is a plurality of television camera ₁ 1 -
Is a diagram showing a conventional example of connecting a 1 _n in parallel, a plurality of television cameras 1 ₁ to 1 _n of the video display is switched by the switching device 2 by the operation from the console 11 3
Will be displayed on the screen.

[0004] Figure 14 is a diagram showing a television camera ₁ 1 to 1 _n, which is configured as a LAN, respectively connecting the computer unit 4 ₁ to 4 _n to a plurality of television cameras ₁ 1 to 1 _n the computer equipment 4 ₁ to 4
_n and the center device 5 constitute a LAN. The output of the center apparatus 5 is inputted to the switching device 2, the image of a plurality of television cameras 1 ₁ to 1 _n by the operation of the console 11 is displayed on the display device 3 on the screen is switched by the switching device 2.

The television cameras 11 ₁ to 1 _n are mounted on angle-of-view adjusting devices 12 _{1 to} 12 _n , respectively. The switching device 2 adjusts the angle of view by operating the console 11. Can also. The angle of view is adjusted by adjusting the pan (movement in the horizontal direction), the tilt (movement in the vertical direction) and the zoom ratio.

[0006] On the screen of the display device 3, it can either be one by one displaying video from each television camera 1 ₁ to 1 _n, or may be displayed multiple images simultaneously. Also, switching of each television camera 1 ₁ to 1 _n can also be adapted automatically be switched in accordance with the procedure determined in advance.

[0007]

In such a conventional apparatus, when the parallel connection as shown in FIG. 13 is employed, it is necessary to draw cables by the number of television cameras, which increases the cost. That is, the cost required for facilities and construction for securing a space for accommodating the cable is higher than the cost of the cable itself.

Further, in the case of the LAN configuration shown in FIG. 14, the space for accommodating the cable is small and the cost is low. Get higher.

The present invention has been made in such a background, and an image which can simplify wiring facilities and reduce installation costs by connecting a plurality of television cameras with a small number of wires. It is intended to provide a transfer system.

[0010]

A first aspect of the present invention is a video transfer system. A feature of the present invention is that a pair of signal transmission cables are provided, and a synchronization signal generation cable is provided on the cables. A device, a control signal generating device, and a video signal receiving device are connected, and the cable is provided with a plurality of adapters for connecting a television camera, respectively, and the adapter controls the control signal generated by the control signal generating device. A switch that is individually closed according to a signal, wherein the synchronization signal circuit of the television camera bypasses the switch, and the video signal of the television camera is connected to the cable via the switch. is there.

That is, the synchronizing signal generator is shared by a plurality of television cameras, and all the television cameras are configured to perform photographing in synchronization, and control signals are transmitted to an adapter to which a desired television camera is connected. By transmitting, the video signal of the television camera is transmitted to the video signal receiving device via the switch. As described above, a desired video signal can be obtained by transmitting a control signal to an adapter to which a desired television camera is connected. At this time, since the synchronization signal generator and the television camera are connected in parallel, the number of cables required for connection may be smaller than the number of television cameras.

The control signal generator includes means for transmitting the control signal to the cable during a retrace period of the synchronization signal transmitted by the synchronization signal generator, and the control signal individually designates a television camera. It is desirable to include an identifier to be used.

[0013] It is preferable that the adapter has means for supplying a synchronizing signal to the television camera.
The cable may be a coaxial cable, a twisted pair cable, or a parallel cable.

[0014] It is preferable that a means is provided between the television camera and the switch for driving a video signal of the television camera by an electric current.
Thus, the video signal is driven by the cable with a higher impedance than the cable impedance, so that the video signal can be transmitted without disturbing the cable impedance.

If it is difficult to synchronize the television cameras with one synchronization signal generator, each television camera can autonomously shoot.

That is, a pair of signal transmission cables are provided, a synchronization signal generator, a control signal generator, and a video signal receiver are connected to the cable, and the cable is provided with a plurality of adapters. The adapter includes switches that are individually closed in accordance with control signals generated by the control signal generator. The adapters are respectively connected to image memories, and video signals read from the image memories are transmitted through the switches. The readout circuit of the image memory may be configured to be synchronized with a synchronization signal transmitted by the synchronization signal generator. It is desirable that a television camera be connected to the writing circuit of the image memory.

According to this, the video signal photographed by the television camera is written into the memory for reading out in synchronization with the synchronization signal generation device at a timing unique to the television camera, and the readout is performed by the synchronization signal generation device. Make it happen synchronously. In this way, by using the memory to compensate for the synchronization deviation of the television camera,
The video transfer system of the present invention can be realized even if an asynchronous television camera is used as the synchronization signal generator.

[0018] It is preferable that a means is provided between the image memory and the switch for driving a video signal of the image memory by current. Thus, the video signal is driven by the cable with a higher impedance than the cable impedance, so that the video signal can be transmitted without disturbing the cable impedance.

A pair of signal transmission cables are provided, and one of the cables is connected to a synchronization signal generator and a control signal generator, and the other is connected to a video signal receiver. A plurality of adapters for connecting a television camera to each of the two cables are provided in common, and the adapter is provided with a control signal generated by the control signal generator supplied by the one cable. Therefore, it is possible to include a switch that is individually closed, and the video signal of the television camera can be connected to the other cable via the switch.

Also in the case of this configuration, it is desirable to have a means interposed between the television camera and the switch and to drive a video signal of the television camera by an electric current. This is effective when applied to a case where it is still difficult to increase the impedance for driving a video signal by means for driving with a current. That is, when the number of installed television cameras needs to be increased, the present invention is suitable for a configuration in which a high impedance is provided so as not to disturb the impedance of the cable.

A second aspect of the present invention is a connector for a coaxial cable, which is characterized by a shield connector provided with a means for inserting a shield of a coaxial cable, and a connector which breaks through a sheath of a core wire to form a sheath. And a core connector provided with a means for being inserted and having a tip in contact with the core wire. Thereby, the adapter of the television camera can be easily attached to the cable.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a video transfer system according to a first embodiment of the present invention. FIG. 2 is a block diagram of a main part of the adapter.

The present invention relates to a video transfer system. The present invention is characterized in that a coaxial cable 10 as a pair of signal transmission cables is provided.
To 0, the synchronization signal generator 6, the control signal generator 7,
Is connected to the video signal receiving apparatus 8, each of the coaxial cable 10 provided with a plurality of adapters 9 ₁ to 9 _n for connecting the television camera 1 ₁ to 1 _n, the adapter 9
Each of _{1 to} 9 _n includes a switch 14 that is individually closed according to a control signal generated by the control signal generator 7, and includes a synchronization signal circuit 16 for the television cameras ₁₁ to 1 _n.
Bypasses the switch 14 and sets the television cameras ₁₁ to 1
The video signal of _n is transmitted through the switch 14 to the coaxial cable 10.
It is connected to.

The control signal generator 7, and transmits the control signal to the flyback period of the synchronizing signal the synchronizing signal generator 6 is transmitted to the coaxial cable 10, the television camera 1 ₁ to 1 _n for the control signal Contains individually specified identifiers.

A current driving circuit 18 is provided between the television camera 1 _i (i = 1 to n) and the switch 14 and drives the video signal of the television camera 1 _i by current. I have. This current drive circuit 18 has an FE of as small as possible (1 pF or less) of Ci.
It can be realized by T (field effect transistor). It is desirable that the distance between the coaxial cable 10 and this FET be as short as possible.

[0026]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. 1 and 2 are as described above. FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention. FIG. 4 is a diagram for explaining the flyback period.
FIG. 5 is a diagram showing a configuration of the control signal. In the first embodiment of the present invention, the television cameras ₁₁ to 1 _n operate in synchronization with the synchronization signal of the synchronization signal generator 6. This synchronizing signal is transmitted through the adapters 9 _{1 to} 9 _n to the television cameras ₁₁ to 9
1 is supplied to the _n, the synchronization signal synchronized with the synchronizing signal circuit 16 of the television camera 1 ₁ in to 1 _n with a synchronizing signal generator 6 generates. As a result, the television camera 1 ₁
１1 _n all take pictures at the same timing.

A person who monitors using the television cameras 1 ₁ to 1 _n operates the console 11 to receive a video signal from the video signal processing unit 17 of a desired television camera 1 _i. Display device 3 received by device 8
You can watch it at This operation will be described.

When the television cameras 1 ₁ to 1 _n are shooting in synchronization with the synchronizing signal of the synchronizing signal generator 6, each television camera 1 _i has a blanking period as shown in FIG. Occur. The retrace period is the time from when the scanning started from the top of the screen ends at the bottom of the screen to when the scanning starts again from the top of the screen. During this return period,
As shown in FIG. 4, no video signal is transmitted. The blanking period using the control signal generator 7 sends a control signal to each television camera 1 ₁ to 1 _n through the coaxial cable 10. Control signal, as shown in FIG. 5 consists of a camera ID and control information as an identifier assigned respectively to each of the television camera 1 ₁ to 1 _n.

As shown in FIG. 3, when the control signal receiving section 13 of the adapter 9 _i receives the camera number (S1), it is determined whether the number that is assigned to the self (S
2). As a result, if it is determined that the camera number is the camera number assigned to itself, the control information following this camera number is received (S3). Information for performing control is written in the control information. Switch 1
There are four closing, pan, tilt or zoom ratio adjustments.
If the control point is the switch 14 is closed, the switch 14
Is closed for a predetermined time (S5). Here, the predetermined time is
This is the time when one frame of video signal is transmitted from the television camera _1i . After a predetermined time has elapsed (S
7) The switch is opened (S8). If the control location is the pan, tilt, or zoom ratio, control of a predetermined location is performed (S6). Adjusting the pan and tilt is performed by shooting angle adjusting device 12 _i. The adjustment of the zoom ratio is performed by operating a lens mechanism.

In this way, the switch 14 of the desired adapter 9 _i is closed by the operation from the console 11, and one frame of video signal is transmitted from the television camera 1 _i to the coaxial cable 10. The video signal for one frame is received by the video signal receiving device 8 and is displayed on the display device 3.
Is displayed. In addition, the switching of the video signal may not be performed each time the console 11 is operated, but may be automatically switched according to a predetermined procedure.

Since the video signal is driven by the current drive circuit 18 into the coaxial cable 10 with a higher impedance than the impedance of the coaxial cable 10, the video signal can be transmitted without disturbing the impedance of the coaxial cable 10.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. Figure 6 is an overall configuration diagram of the present invention the second embodiment, FIG. 7 is a principal block diagram of the adapter 9 _i of the second embodiment of the present invention. The second embodiment of the present invention is used when it is difficult for the television camera 1 _i to synchronize with the synchronization signal generated by the synchronization signal generator 6.

[0033] In the present invention the second embodiment, the television camera 1 _i has done work photographing accordance autonomous clock signal. The frame memory 15 is a memory for recording one frame of video signal output from the television camera 1 _i , and performs reading in synchronization with a synchronization signal of the synchronization signal generator 6.

The television camera 1 _i performs photographing in accordance with an autonomous clock signal, and writes a video signal for each frame into the frame memory 15. At this time, the write timing is performed in synchronism with the autonomous clock signal of the television camera 1 _i. The operation of the second embodiment of the present invention is the same as that of the flowchart shown in FIG.

[0035] When sending a control signal to a desired adapter 9 _i in accordance with an operation from the console 11 in the blanking period, the synchronizing signal generating apparatus according to the same procedure as the present invention a second embodiment 6
The switch 14 is closed in synchronization with the synchronizing signal. When the switch 14 is closed, the video signal for one frame recorded in the frame memory 15 is transmitted to the coaxial cable 10, and the video signal is received by the video signal receiving device 8 and displayed on the display device 3.

As described above, in the second embodiment of the present invention, when the television camera 1 _i is not synchronized with the synchronizing signal of the synchronizing signal generator 6, the synchronization deviation can be absorbed by the frame memory 15. .

A current drive circuit 18 is interposed between the frame memory 15 and the switch 14 and drives a video signal of the frame memory 15 by a current. Since the video signal is driven by the current drive circuit 18 into the coaxial cable 10 with a higher impedance than the impedance of the coaxial cable 10, the video signal can be transmitted without disturbing the impedance of the coaxial cable 10.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIGS. FIGS. 8 to 10 are views showing a connector configuration for connecting the adapters 9 _{1 to} 9 _n to the coaxial cable 10. As shown in FIG. 8, the coating of the coaxial cable 10 is peeled off, and the shield 20 is partially exposed.
Further, a part of the shield 20 is removed to expose the covering of the core wire 21.

As shown in FIG. 9, the shield connector 30 is brought into contact with the shield 20 and is pressed into contact with the shield 20 using a tool such as pliers. As for the core wire 21, a V-shaped core connector 31 is inserted by piercing the sheath of the core wire 21, and the core wire 21 is brought into contact with the end with the core wire 21 interposed therebetween. Thereby, the coaxial cable 10
A connector can be attached to each of the shield 20 and the core wire 21.

As shown in FIG. 10, the core connector 31 is previously mounted on the shield connector 30 with the insulating layer 22 interposed therebetween, and the two divided shield connectors 30 are connected by screws 23. You can also At this time, the force by which the tip of the core connector 31 breaks through the coating of the core 21 and the force by which the screw 23 couples the two divided shield connectors 30 can be shared.

(Fourth Embodiment) FIG. 11 shows a fourth embodiment of the present invention.
This will be described with reference to FIG. FIG. 11 is an overall configuration diagram of the fourth embodiment of the present invention. In the fourth embodiment of the present invention, a twisted pair cable 50 is used instead of the coaxial cable 10 shown in the first to third embodiments of the present invention. Further, a two-core parallel cable can be used instead of the twisted pair cable 50.

(Fifth Embodiment) FIG. 12 shows a fifth embodiment of the present invention.
This will be described with reference to FIG. FIG. 12 is a view for explaining the fifth embodiment of the present invention. In the fifth embodiment of the present invention, two twisted pair cables 51 and 52 are provided, a synchronous signal generator 6 and a control signal generator 7 are connected to the twisted pair cable 52, and a video signal is connected to the twisted pair cable 51. A receiving device 8 is connected, and an adapter 9 _i for connecting the television camera 1 _i is connected to each of the two twisted pair cables 51 and 52.
The adapter 9 _i includes switches 14 individually closed in accordance with control signals generated by the control signal generator 7 supplied by the twisted pair cable 52, and the video signals of the television camera 1 _i are provided. Is connected to the twisted pair cable 51 via the switch 14.

[0043] In the present invention the fifth embodiment is interposed between the television camera 1 _i and switch 14, and a current drive circuit 18 for driving the current video signal of the television camera 1 _i. With this current drive circuit 18, the video signal is transmitted to the twisted pair cable 5.
1 is driven by the twisted pair cable 51 with a higher impedance than the impedance of
A video signal can be transmitted without disturbing the impedance of the twisted pair cable 51.

However, it is necessary to further increase the number of television cameras 1 _i installed.
In the case where it is difficult to maintain a high impedance when driving a video signal by using only the 8 pairs, as shown in the fifth embodiment of the present invention, two twisted pairs for transmitting a synchronization signal and transmitting a video signal are used. It is effective to use the cables 51 and 52.

In the fifth embodiment of the present invention, an example using a twisted pair cable has been described, but a coaxial cable or a parallel cable may be used. In particular, by using three pairs (six cores) of parallel cables, one pair is used for power supply, one pair is used for synchronous signal transmission, and one pair is used for video signal transmission. The configuration can be easily realized.

(Summary of Embodiment) In the first to third embodiments of the present invention, the coaxial cable 10 can be extended up to about 300 meters. In addition, the number of connection can be television camera 1 _i is greater than or equal to 100 units.

In the case of a color television camera for CCTV, the synchronizing connection may not operate normally due to the synchronizing signal from the synchronizing signal generator 6, so that the system shown in the second embodiment of the present invention is suitable. There is.

The camera number of the control signal can be constituted by 8-bit data when the number of television cameras _1i is 256.

Here, the description has been made assuming that the video signal is switched on a frame basis. However, the video signal can be switched on a field basis or on a fixed time basis irrespective of the frame or the field.

In the case of a color synchronizing signal, a black burst is used. In the first embodiment of the present invention, the synchronizing signal generated by the synchronizing signal generation circuit 6 and the video signal generated by the video signal processing unit 17 are superimposed, so that the video signal itself does not require a synchronizing signal. In the fifth embodiment of the present invention, since the video signal is transmitted to the video signal receiving device 8 via the twisted pair cable 51 alone, the video signal processing unit 17 adds a synchronization signal to the video signal.

[0051]

As described above, according to the present invention,
By connecting a plurality of television cameras with a small number of wires, wiring equipment can be simplified and installation costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a video transfer system according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a main part of an adapter.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 4 is a diagram for explaining a flyback period.

FIG. 5 is a diagram showing a configuration of a control signal.

FIG. 6 is an overall configuration diagram of a second embodiment of the present invention.

FIG. 7 is a block diagram of a main part of an adapter according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a connector configuration for connecting an adapter to a coaxial cable.

FIG. 9 is a diagram showing a connector configuration for connecting an adapter to a coaxial cable.

FIG. 10 is a diagram showing a connector configuration for connecting an adapter to a coaxial cable.

FIG. 11 is an overall configuration diagram of a fourth embodiment of the present invention.

FIG. 12 is a diagram for explaining a fifth embodiment of the present invention.

FIG. 13 is a diagram showing a conventional example in which a plurality of television cameras are connected in parallel.

FIG. 14 is a diagram showing a television camera configured as a LAN.

[Explanation of symbols]

1 ₁ to 1 _n Television camera 2 Switching device 3 Display device 4 ₁ to 4 _n Computer device 5 Center device 6 Synchronous signal generator 7 Control signal generator 8 Video signal receiver 9 _{1 to} 9 _n Adapter 10 Coaxial cable 11 Operation Desk 12 _{1 to} 12 _n Angle-of-view adjuster 13 Control signal receiving unit 14 Switch 15 Frame memory 16 Synchronous signal circuit 17 Video signal processing unit 18 Current drive circuit 20 Shield 21 Core wire 22 Insulation layer 23 Screw 30 Shield connector 31 Core connector 50-52 twisted pair cable

Claims (11)

[Claims] 1. A pair of signal transmission cables are provided, and a synchronization signal generator, a control signal generator, and a video signal receiver are connected to the cables, and a television camera is connected to each of the cables. A plurality of adapters, the adapters each including a switch that is individually closed in accordance with a control signal generated by the control signal generator, the synchronization signal circuit of the television camera bypasses the switch. A video signal from the television camera is connected to the cable via the switch. 2. A pair of signal transmission cables are provided, a synchronization signal generator, a control signal generator, and a video signal receiver are connected to the cable, and the cable is provided with a plurality of adapters, The adapter includes switches that are individually closed in accordance with control signals generated by the control signal generator, and each of the adapters is connected to an image memory, and a video signal read from the image memory is transmitted through the switch. Wherein the readout circuit of the image memory is synchronized with a synchronization signal transmitted by the synchronization signal generator. 3. The video transfer system according to claim 2, wherein a television camera is connected to the writing circuit of the image memory. 4. A pair of signal transmission cables are provided, and one of the cables is connected to a synchronization signal generator and a control signal generator, and the other of the cables is connected to a video signal receiver. A plurality of adapters for connecting a television camera are respectively provided in common to the two cables, and the adapter is provided with a control signal generated by the control signal generator supplied by the one cable. Therefore, the video transmission system includes switches that are individually closed, and the video signal of the television camera is connected to the other cable via the switch. 5. The control signal generator includes means for transmitting the control signal to the cable during a retrace period of the synchronization signal transmitted by the synchronization signal generator. The video transfer system according to any one of claims 1 to 4, further comprising an identifier specified in (1). 6. The video transfer system according to claim 1, wherein said cable is a coaxial cable. 7. The video transfer system according to claim 1, wherein said cable is a twisted pair cable. 8. The video transfer system according to claim 1, wherein said cable is a parallel cable. 9. The video transfer system according to claim 1, further comprising: means interposed between the television camera and the switch, for driving a video signal of the television camera by an electric current. 10. The video transfer system according to claim 2, further comprising: means interposed between said image memory and said switch, for driving a video signal of said image memory by current. 11. A shielded connector provided with means for sandwiching a shield of a coaxial cable, and a cored connector provided with means for piercing a sheath of a core wire, being inserted into the sheath, and having a tip contacting the core wire. A connector for a coaxial cable, characterized in that: