JPH1198490A - Monitor image signal transmission system and circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the hardware of a transmitter side of a monitor image signal by allowing an intermediate monitor station to branch an image signal received at a monitor image signal branch circuit into two, decoding one output at a decoding circuit of its own station, displaying the decoded signal on a television monitor and sending the other output to a succeeding station via a line interface. SOLUTION: A monitor station 1 is made up of a TV camera 120, a coding circuit 110 that codes a monitor image signal received from the TV camera into a digital signal, and a transmitter 101 that sends the digital signal coded by the coding circuit onto a transmission line. Monitor stations 2, 3 have transmitters 102, 103 that receive a monitor image signal on a transmission line and sends the signal again to a transmission line, a branch circuit 200 that branches the monitor image signal and sends its output to a decoding circuit 130 and a succeeding monitor station. The signal is displayed on a television monitor 140 and sent to the succeeding station, then number of the coding circuits 110 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring image signal for transmitting a monitoring image signal input from a television camera of one monitoring station via a transmission line, displaying the monitoring image signal on a television monitor of the other monitoring station, and performing monitoring. Related to transmission systems.

[0002] With the development of communication technology and image signal processing technology, various monitoring systems based on images using a television camera and a television monitor have been widely adopted and put to practical use. However, when monitoring by image signals, ITV
(Industrial Television) video transmission also requires a 32 Mbps transmission bandwidth, and the hardware required to transmit such a wide-band surveillance image signal is expensive. Is required to be built.

[0003]

2. Description of the Related Art FIG. 6 is a diagram (part 1) for explaining a conventional example. In the figure, 1 to 4 are monitoring stations, 101 to 104 are transmission devices for transmitting monitoring image signals between the monitoring stations 1 to 4, and 11 in the transmission devices 101 to 104 is, for example,
Interface circuit for 6 Mbps image signal (6M in the figure)
The transmission device 101 is connected to a television camera (shown as a TV camera in the figure) 120, a distribution circuit 201, and an encoding circuit 110.
The interface circuit 11 is accommodated in each of the components 04, and a decoding circuit 130 and a television monitor (shown as a TV monitor in the figure) 140 are connected to the interface circuit 11.

In such a configuration, the television camera 120
Input a monitoring image to be monitored, for example, NTSC (Nat
ional Television System Committee) to output surveillance image signals. The monitoring image signal of NTSC is divided into a number of parts corresponding to the number of stations to which the monitoring image signal is transmitted by the distribution circuit 201, and input to the encoding circuit 110. The encoding circuit 110 converts the monitoring image signal of NTSC. It is encoded into a digital surveillance image signal, and is transmitted via the interface circuit 11 of the transmission apparatus 101 and the line to the transmission apparatuses 102 to 1.
04.

[0005] In each of the transmission devices 102 to 104,
The digital monitoring image signal received via the transmission path and the interface circuit 11 is decoded into an NTSC monitoring image signal by a decoding circuit 130, and the TV monitor 14
A monitoring image is displayed at 0.

FIG. 7 is a diagram (part 2) for explaining a conventional example. 101N (Normal), 101E (Emergency),
Reference numerals 102N and 102E denote duplex transmission devices, and reference numeral 11 in the transmission devices 101N, 101E, 102N, and 102E denotes an image signal interface circuit.

In the figure, an NTSC surveillance image signal output from a television camera 120 is split into two by a distribution circuit 201 and input to an encoding circuit 110.
Then, the NTSC image signal is encoded into a digital image monitoring image signal, and is transmitted via the interface circuit 11 of the transmission devices 101N and 101E and the transmission lines LN and LE.
The data is transmitted to the transmission devices 102N and 102E.

In each of the transmission devices 102N and 102E, the transmission lines LN and LE and the interface circuit 1
1 is decoded into an NTSC monitoring image signal by a decoding circuit 130, and a switching device 301 transmits the signal to the transmission device 101 when the transmission path LN is normal.
Switching to the monitoring image signal side from N, and when the transmission line LN is abnormal, switching to the monitoring image signal side from the transmission device 101E and displaying the monitoring image on the television monitor 140.

[0009]

In the above-mentioned conventional example (No. 1), the encoding circuit 110 connected to the transmission apparatus 101 for transmitting a monitoring image according to the number of monitoring stations monitoring the monitoring image signal. , And the interface circuit 11 of the transmission apparatus 101 is required, and the amount of hardware increases. Further, assuming that the transmission band of the monitoring image signal is 6 Mbps, the band used as the transmission path is also equal to the number of monitoring stations × 6 Mbps.
Increase in ps.

In the conventional example (No. 2), encoding is performed after the NTSC surveillance image signal is branched into two.
The encoding circuit 110 and the decoding circuit 130 are 2
Each unit is required, and hardware increases.

Further, when the transmission path is duplicated and monitored by the television monitors 140 provided at a plurality of points,
Hardware increases. The present invention is based on the image signal.
When performing various types of monitoring, an attempt is made to realize an economical monitoring image signal transmission system.

[0012]

FIG. 1 is a diagram for explaining a first principle of the present invention. The figure shows an image signal transmission system in which a monitoring image signal input from a television camera 120 of one monitoring station 1 is monitored by a television monitor 140 of a plurality of monitoring stations 2 to 4.

The monitoring station 1 for inputting the monitoring image signal includes a television camera 120 for inputting the monitoring image signal, an encoding circuit 110 for encoding the monitoring image signal input from the television camera 120 into a digital signal, Transmission device 1 for transmitting a digital signal encoded by a circuit onto a transmission line
01.

Further, the monitoring stations 2 and 3 at the intermediate points for monitoring the monitoring image signal receive the monitoring image signal input from the transmission path and transmit the received monitoring image signal to the transmission path. And a branch circuit 200 that branches the received monitoring image signal, sends one output to the decoding circuit 130, and sends the other output to the next monitoring station, and receives the other output of the branch circuit 200. , A decoding circuit 130 for decoding the encoded monitoring image signal, and a decoding circuit 1
The television monitor 140 is configured to display a monitor image signal output from the television monitor 30.

Further, the monitoring station 4 at the end receiving the monitoring image signal includes a transmission device 104 for receiving the monitoring image signal input from the transmission line, and a decoding device for decoding the digital monitoring image signal received by the transmission device 104. It comprises a circuit 130 and a television monitor 140 for displaying a monitoring image signal output from the decoding circuit 130.

With this configuration, when the monitoring images input from the television camera 120 of the monitoring station 1 are monitored by the plurality of monitoring stations 2 to 4, the monitoring images 2 and 3 in the intermediate monitoring stations 2 and 3 receive the monitoring image signal by the branch circuit 200. The image signal is branched into two, one output is decoded by the decoding circuit 130 of the own station and displayed on the television monitor 140 for monitoring, and the other output is sent to the next station via the line interface 10. By doing so, the encoding circuit 11 on the sending side of the monitoring image signal
The number of zeros can be reduced, and an image signal monitoring system can be constructed economically.

FIG. 2 is a diagram for explaining the second principle of the present invention. The figure shows a surveillance image signal transmission system in which a surveillance image signal input from one television camera 120 is sent to a surveillance monitoring station 2 via duplex transmission lines LN and LE to perform monitoring.

The monitoring station 1 for inputting the monitoring image signal includes transmission devices 101N and 101 connected to a duplex transmission path.
E, a television camera 120 for inputting a monitoring image signal,
An encoding circuit 110 for encoding the monitoring image signal input from the television camera 120 into a digital signal; and a branch for branching and transmitting the digital signal encoded by the encoding circuit 110 to the duplexed transmission devices 101N and 101E. The circuit 200 is configured.

Further, the opposite monitoring station 2 receiving the monitoring image signal includes the duplexed transmission devices 102N, 102N, 1D receiving the image signals input from the duplicated transmission lines LN, LE.
02E, an image signal output from the duplexed transmission devices 102N and 102E, and a switch 301 for selecting and outputting one of the input image signals, and decoding an encoded monitoring image signal output from the switch 301. Decoding circuit 13
0 and a television monitor 140 for displaying a monitoring image signal output from the decoding circuit 130.

With such a configuration, the monitoring image input from the television camera 120 of the monitoring station 1 is used to duplicate the transmission line L
In the case of transmission via N and LE and monitoring by the opposite monitoring station 2, after the monitoring image signal input from the television camera 120 is encoded by the encoding circuit 110, the monitoring image signal is branched into two by the branch circuit 200. And output the transmission device 101N, 1
01E to the opposing transmission devices 102N and 102E via the line interface 10E of the monitoring station 2 on the receiving side.
Then, the monitor image signal received from the transmission devices 102N and 102E is selected by the switch 301, and then decoded by the decoding circuit 130.
, The number of the encoding circuits 110 in the monitoring station 1 on the transmitting side of the circuit image signal and the number of the decoding circuits 130 in the monitoring station 2 on the receiving side can be reduced, and the monitoring image signal transmission system can be economically implemented. Can be built.

[0021]

FIG. 3 is a diagram for explaining an embodiment of the present invention. The figure shows an embodiment in which the first principle and the second principle of the present invention are combined, and a plurality of monitoring stations 1 to 4 are connected in a loop to provide a configuration having a duplicated transmission path. They are equivalent.

In the figure, reference numeral 1 denotes a monitoring station. The transmission device 101 of the monitoring station 1 includes an interface circuit 11 of 6 Mbps, and further includes an encoding circuit 110 for encoding a monitoring image signal from the television camera 120; The output is connected to a branch circuit 200 that branches the output into two.

Reference numerals 102 to 104 denote transmission devices provided in the monitoring stations 2 to 4, which include an interface circuit 11 and which are provided for digital monitoring image signals received from the clockwise and counterclockwise directions of the loop transmission path. The switching circuit 300 is connected to the decoding circuit 130 to select and output one, and the switching circuit 300 displays a monitoring image on the television monitor 140.

With this configuration, the NTSC image signal output from the television camera 120 is, for example, digitally encoded at 6 Mbps by the encoding circuit 110, and then divided into two by the branching circuit 200 to transmit the same image signal in a loop. It is sent in the clockwise direction and the counterclockwise direction of the road. In each of the transmission devices 102 to 104, a clockwise direction of the loop transmission path,
One of the signals received from the counterclockwise direction is supplied to the switching circuit 300
, And is decoded by the decoding circuit 130 to be displayed on the television monitor 140.

In the embodiment, an example has been described in which a monitoring image signal is input from the transmission apparatus 101 and an image is displayed on the television monitor 140 connected to the transmission apparatuses 102 to 104. However, the number of monitoring stations is limited to four. It is needless to say that the station can be constituted by an arbitrary number of stations. In this case, the surveillance image signal is G.264. According to G.703a, encoding is performed to generate a 6 Mbps signal.
The image signal is not limited to 703a, and may be an image signal encoded according to an arbitrary encoding rule.

Further, in the embodiment of the configuration described in the second principle of FIG. 2, the monitoring stations are changed to the monitoring stations 1 and 2 in FIG.
, And the clockwise direction and the counterclockwise direction of the loop transmission path are the same as the transmission path LN, LE.

With this configuration, the amount of hardware configuring the monitoring image signal transmission system can be reduced.
The system can be constructed economically, and the transmission path can be used efficiently.

Further, the switching circuit 300 for digital use of the present invention selects and outputs one of the monitoring image signals input from two directions, and the other output branches the monitoring image signal to be provided to the next monitoring station. It also has a relay function. Next, the configurations of the branch circuit 200 and the switching circuit 300 used in the present invention will be described below.

FIG. 4 is a diagram for explaining a branch circuit according to the present invention. Reference numeral 210 in the figure denotes a hybrid (indicated by H in the figure), which branches the input digital image signal into three and outputs it. Reference numeral 220 denotes a synchronization signal supply circuit, which encodes a synchronization signal synchronized with the digital network. Supply to the encoding circuit 110 and the decoding circuit 130,
The operation of the decoding circuit 130 can be synchronized with the clock signal of the digital network.

One of the three branched signals is used for checking the normality of the digital image signal at the monitoring station.
FIG. 5 is a diagram illustrating the switching circuit of the present invention. The switching circuit 300 uses the hybrids 311 and 312 to split the clockwise and counterclockwise signals into two, and inputs one of the split signals to a switch (indicated by SW in the drawing) 320 and the other of the split signals. Is sent to the next monitoring station.

One of the monitoring image signals input to the switch 320 is input to the decoding circuit 130, and the digital monitoring image signal is converted into, for example, an NTSC signal, and displayed on the television monitor 140. Further, according to the present invention, the hybrid 313 is provided on the output side of the switch 320 so that the digital signal can be monitored at the signal level. When an abnormality is detected in the signal from the STA, switching is performed so as to select a normal route. When both directions are normal, for example, when the clockwise direction is selected, a selection condition is set.

[0032]

According to the present invention, the input side of the surveillance image signal encodes the signal input from the television camera, and then encodes the signal.
By transmitting in two directions, the number of encoding circuits used can be reduced.

On the receiving side of the monitoring image signal, the switching circuit selects one of the digital signals to be received from the two directions and then performs decoding, thereby reducing the number of decoding circuits to be used.

Further, the switching circuit includes a switch for switching between two signals. The switching circuit branches the input image monitoring signal into two, and inputs one of the signals to the switch.
By transmitting the other to the next monitoring station, an image signal transmission system can be constructed economically.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first principle of the present invention.

FIG. 2 is a diagram illustrating a second principle of the present invention.

FIG. 3 illustrates an embodiment of the present invention.

FIG. 4 is a diagram illustrating a branch circuit of the present invention.

FIG. 5 is a diagram illustrating a switching circuit of the present invention.

FIG. 6 illustrates a conventional example (part 1).

FIG. 7 illustrates a conventional example (part 2).

[Description of Signs] 1-4 Monitoring stations 101-104, 101N, 101E, 102N, 10
2E Transmission device 10 Line interface 11 Interface circuit 110 Encoding circuit 120 Television camera 130 Decoding circuit 140 Television monitor 200 Branch circuit 201 Distribution circuit 210, 311, 312, 313 Hybrid 220 Synchronous signal supply circuit 300 Switching circuit 301 Switching device 320 Switch LN, LE transmission line

Claims (4)

[Claims] 1. An image signal transmission system for monitoring a monitoring image signal input from one television camera on a plurality of monitoring station TV monitors, wherein the monitoring station inputting the monitoring image signal inputs the monitoring image signal. A monitoring system comprising: a television camera; an encoding circuit that encodes a monitoring image signal input from the television camera into a digital signal; and a transmission device that sends out the digital signal encoded by the encoding circuit onto a transmission path. The monitoring station at the intermediate point that monitors the image signal receives a monitoring image signal input from the transmission path, branches the transmission apparatus that sends the received monitoring image signal onto the transmission path, and branches the received monitoring image signal. A branch circuit for sending one output to a decoding circuit and sending the other output to a next monitoring station; and receiving one output of the branch circuit, and encoding an encoded monitoring image signal. A monitoring circuit, comprising a decoding circuit for decoding, and a television monitor for displaying a monitoring image signal output from the decoding circuit, wherein the monitoring station at the end receiving the monitoring image signal receives a monitoring image signal input from a transmission path. , A decoding circuit for decoding a digital surveillance image signal received by the transmission device, and a television monitor for displaying a surveillance image signal output from the decoding circuit. Surveillance image signal transmission system. 2. A surveillance image signal transmission system for transmitting a surveillance image signal input from one television camera to an opposing surveillance station via a duplicated transmission path and monitoring the surveillance image signal. A monitoring station, a transmission device connected to the duplexed transmission line, a television camera for inputting a monitoring image signal, an encoding circuit for encoding the monitoring image signal input from the television camera into a digital signal, An opposite monitoring station configured to branch a digital signal coded by the coding circuit to the duplexed transmission device and to transmit the branched signal to the transmission device, and to receive a monitoring image signal, receives an image input from the duplexed transmission path. A duplex transmission device that receives a signal, a switch that receives an image signal output from the duplex transmission device as an input, selects one of the image signals, and outputs the selected signal. A monitoring circuit configured to decode a coded monitoring image signal output from the switch, and a television monitor configured to display the monitoring image signal output from the decoding circuit. Signal transmission system. 3. The image signal transmission system according to claim 1, wherein the branch circuit includes a branch unit including a hybrid circuit.
A circuit comprising: a synchronization signal supply unit that supplies a synchronization signal to the encoding circuit and the decoding circuit. 4. The image signal transmission system according to claim 1, wherein the switching circuit branches the signal in the up / down direction, one of the branched outputs is input to the switching circuit, and the other output is the other. A circuit comprising: a hybrid circuit for transmitting to an adjacent monitoring station; and a changeover switch for selecting and outputting one of the outputs of one of the two hybrid circuits as an input.