JPH11234655A - Image supervisory system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of lines interconnecting a supervisory device and an image pickup device and to enhance the image quality of a video image in the image supervisory system where pluralities of image pickup devices connect with the supervisory device. SOLUTION: A plurality of image pickup devices 21 connect with a supervisory device 24 via a control signal line 23 and a video signal line 24. Thus, the number of signal lines is decreased. Each image pickup device sends a video signal to the supervisory device via the video signal line upon receipt of a command requesting transmission of its own video signal through the control signal line from the supervisory device. The supervisory device allows a monitor 25 to display the video image for supervision. A supervisory camera not sending a video signal is disconnected from the video signal line by a changeover means, then the video signal is sent to the supervisory device without hindrance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring device, in which a plurality of imaging devices for capturing images of a monitoring area are connected to the monitoring device, and the monitoring device displays the images captured by the imaging device on the monitoring device. The present invention relates to a monitoring system that performs monitoring.

[0002]

2. Description of the Related Art In a conventional image monitoring system, a plurality of imaging devices continuously capture images of entrances and exits of a building and other monitoring areas, and a remote monitoring device monitors images captured by the imaging devices. An image surveillance system for monitoring a surveillance area by displaying the surveillance area has been commercialized. Also,
2. Description of the Related Art In an imaging apparatus, an image monitoring system has been put to practical use in which the presence or absence of an abnormality is determined based on a captured image, and when an abnormality is detected, the image at the time of the abnormality and the preceding and following images are sent to a monitoring apparatus.

[0003] In these conventional monitoring systems, a plurality of imaging devices are connected to the monitoring device in a star configuration.
The monitoring device switches the connection with each imaging device, and displays a video taken by any imaging device on the monitor device.

[0004]

In the above conventional monitoring system, since each of the plurality of imaging devices is connected to the monitoring device by a signal line, the number of signal lines increases and the cost of wiring work increases. There was a problem. On the other hand, a plurality of image pickup apparatuses are connected by a single serial cable, and time-division multiplex transmission of a video taken by each image pickup apparatus as a digital signal of a still image is also performed. However, in this system, there is a problem that there is a time interval between image transmissions in order to ensure a predetermined level of image quality due to the limitation of the transmission capacity of the cable.

According to the present invention, in an image monitoring system in which a plurality of imaging devices are connected to a monitoring device, the number of lines connecting between the monitoring device and the imaging device is reduced, and transmission from the imaging device to the monitoring device is reduced. It is intended to shorten the time interval between the two.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. An image monitoring system according to the present invention is an image monitoring system in which a plurality of imaging devices that capture an image of a monitoring area are connected to the monitoring device, wherein the plurality of imaging devices are serially connected to the monitoring device by a control signal line and a video signal line. Connecting.

[0007] The image pickup apparatus includes an image pickup means for picking up an image of a monitor area, a control signal receiving means connected to a control signal line for receiving a control signal from the monitor apparatus, and a video signal obtained from the image pickup means. The video signal transmitting means to be transmitted and the video signal transmitting means are connected to divide the video signal line into a video signal line on the monitoring device side and a video signal line on the terminal side, and the video signal line on the monitoring device side and the video signal line on the terminal side. Switching means for switching between a state in which the video signal line is connected or a state in which the video signal line and the video signal transmitting means on the monitoring device are connected; and The video signal line and the video signal line on the terminal side are switched to a connected state, and when a command for transmitting own video is received from the receiving unit, the video signal line on the monitoring device side and the video signal transmitting means are connected. Switch to state ; And a control that means.

In each imaging device of this image monitoring system, the terminal video signal line and the monitoring device video signal line are always connected, and each imaging device is disconnected from the video signal line. . Further, the imaging device that has received the command to transmit its own image from the monitoring device connects the own video signal transmitting means to the monitoring device side video signal line and monitors the video signal of the video obtained from its own imaging device. Send to device. The monitoring device displays this image on the monitoring device to monitor the monitoring area.

According to this image monitoring system, an analog signal can be used as a video signal, and a high-quality video can be displayed on the monitoring device. Further, since the monitoring device and the imaging device are only connected by one control signal line and one video signal line, the number of signal lines is reduced, and the cost required for wiring work can be reduced. it can.

[0010]

Embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows an overall configuration of a first monitoring system to which an image monitoring system of the present invention is applied.

A controller 1 is installed in a building to be monitored, and a plurality of image sensors 2, a fire sensor 3, an emergency button 4, and a mode setting device 5 are connected to the controller 1.
The controller 1 is connected via a telephone line 6 as a communication line to a security center device 7 provided at a remote security center. The connection between the image sensor 2 and the controller 1 is made by an analog signal line 8 and a digital signal line 9. The analog signal line 8 is formed of a coaxial cable and transmits a video signal (NTSC system), and the digital signal line 9 is formed of a twisted pair line and transmits a control signal based on a digital signal.

Here, the operation of the entire monitoring system of FIG. 1 will be briefly described. The mode setting unit 5 sets the monitoring system to the alert release mode or the alert set mode.
When the sensor detects an abnormality in the alert set mode, the controller 1 sends a command to the security center device 7 via the telephone line 6.
An abnormal signal indicating that an abnormality has occurred is transmitted. When an abnormal signal is output from the fire sensor 3 and the emergency button 4,
The controller 1 transmits data indicating the type of abnormality and the location where the abnormality has occurred to the security center device 7 through the telephone line 6. The method for detecting and transmitting these abnormal signals is well known in the art, and thus further description is omitted.

A plurality of image sensors 2 are installed in a building,
A monitoring area including a monitoring target such as a window or a door is photographed, and the presence or absence of an abnormality such as intrusion is determined from the obtained image. Various methods have been proposed as a method for determining the presence or absence of the abnormality, and an arbitrary method can be adopted. An example of a method for detecting an abnormality from an image will be described with reference to FIG.

FIG. 2A shows a reference image, FIG. 2B shows a current image,
(C) is an image displaying the difference between the reference image and the current image. The current image in (B) is the latest image obtained by the image sensor 2 and is compared with the reference image in (A) to extract the difference (C) between the two images. If the difference between the two images exceeds a predetermined reference value, it is determined that an abnormality has occurred in the monitoring area.
The reference image of (A) includes (A) the image sensor 2
Image obtained when the camera was installed, (b) an image obtained when shifting to the alert set mode, (c) at predetermined time intervals (eg,
(10 frames), (d) one or more previous images of the current image, and the like. The current image (B) (image at the time of occurrence of an abnormality) is displayed on the security center device 7.

The operation of the entire image monitoring system when the image sensor 2 detects an abnormality will be described with reference to the time chart of FIG. When the mode is changed by the setting of the mode setting device 5, the controller 1 transmits a mode change signal to all the image sensors 2 through the digital signal line 9. In addition, the controller 1 controls each of the image sensors 2A, 2B.
, A status call signal is sequentially sent (polling).

Each of the image sensors 2A, 2B... Sends a status signal, that is, a normal signal or an abnormal signal to the controller 1 through the digital signal line 9 in response to the status call signal. After shifting to the alert set mode, a certain image sensor 2
When A sends an abnormal signal in response to the state call signal, the controller 1 dials and connects to the security center device 7 via the telephone line 6. In addition, an abnormal image transmission request signal is transmitted to the image sensor 2A that has transmitted the abnormal signal.

The image sensor 2A transmits an abnormal image to the controller 1 in response to an abnormal image transmission request signal. At this time, the image data at the time of occurrence of the abnormality is converted into an analog video signal, and the analog signal line 8 controls the controller 1.
Sent to. Although it takes a relatively long time to transmit and receive a video signal, in this example, the video signal is transmitted and received through a dedicated analog signal line 8. Therefore, during that time, the controller 1
Communication between the sensor 2 and each sensor 2 is enabled by a digital signal line 9.

When receiving a response from the security center device 7, the controller 1 transmits the abnormal signal sent from the image sensor 2A and the image at the time of occurrence of the abnormality to the security center device 7 via the telephone line 6. When this transmission ends, an abnormal image erasure signal is output to the image sensor 2A, and the image sensor 2A erases the stored abnormal image and continues the monitoring operation.

The security center apparatus 7 displays an abnormal image on the display unit in response to the reception of the abnormal signal, and the controller checks the abnormal state by looking at the image. When an abnormal state is confirmed, a reception end signal to the controller 1 is output. When receiving the reception end signal, the controller 1 releases the telephone line 6 connected to the security center device 7, and outputs a status call signal to the next image sensor 2B. Thereafter, the same operation as described above is repeated.

Here, a method of checking the state of the security center device 7 will be described. The security center device 7 creates an image at the time of occurrence of an abnormality from the video signal sent from the controller 1. This image corresponds to FIG.
The result is as shown in FIG. The image sent from the image sensor 2 to the security center device 7 may include images of several frames before and after the abnormality in addition to the image at the time of occurrence of the abnormality. In this case, by comparing the image at the time of occurrence of the abnormality with the images before and after the abnormality, the controller can improve the accuracy of checking the abnormal state.

Next, specific configurations of the controller 1, the image sensor 2, and the security center device 7 used in the image monitoring system will be described. FIG. 4 shows the configuration of the image sensor 2, and FIG. 5 shows the contents of the storage means in the image sensor 2.
The image sensor 2 includes a control unit 201 including a CPU and a power supply 202. Each part in the sensor is controlled by the control unit 201 and receives power from a power supply 202. The power supply 202 includes a conversion device that converts an AC voltage supplied from the outside into a DC voltage. Note that instead of providing the power supply 202 in the image sensor 2, power may be supplied from the controller 1.

The control means 201 has a storage means 220
Is connected. The contents of the storage means 220 will be described with reference to FIG. The storage means 220 has a program area 221 storing a program for causing the image sensor 2 to execute a predetermined operation, a parameter area 222 storing parameters, a work area 223, and a monitoring area. A status storage area 224 for storing the distinction between normal and normal and a mode storage area 225 for storing whether the monitoring area is in the alert set mode or the alert release mode are provided.

The storage means 220 further includes an image pickup means 203
The reference image storage area 226, the current image storage area 227, the abnormal image storage area 2
28. In the current image storage area 227, the imaging unit 2
The latest image captured by 03 and the image up to two frames before the latest image are stored. The reference image storage area 226 stores the image described with reference to FIG.

When an abnormality is detected in the current image, the abnormal image storage area 228 stores the current image at that time as the image at the time of occurrence of the abnormality, and further stores the image of the previous two frames and the image of the subsequent seven frames. Images of a total of 10 frames are stored.
Returning to FIG. 4, the imaging unit 203 that captures an image of the monitoring area
It is composed of a CCD camera and has sensitivity from the visible region to the infrared region. Infrared light emitting means 204 is provided,
When it becomes dark, such as at night, infrared rays are emitted to the monitoring area.

The image processing means 205 compares the current image stored in the storage means 220 with the reference image to determine whether an abnormality has occurred. One example of this determination logic has already been described with reference to FIG. Display means 20
Reference numeral 6 denotes an LED, which is turned on when an abnormality is detected, turned off when no abnormality is detected, and displays the presence or absence of the abnormality detection outside the image sensor 2.

The communication means 207 is an interface for transmitting and receiving signals to and from the controller 1, and is connected to the controller 1 via the digital signal line 9. Image output means 2
Reference numeral 08 denotes an interface for outputting an image at the time of occurrence of an abnormality, which is connected to the analog signal line 8 via the switching unit 209. The analog signal line 8 is, as shown in FIG.
The controller 1 and each image sensor 2 are connected in series.
The switching unit 209 of the image sensor 2 connects the input side and the output side of the analog signal line 8 in a normal state, disconnects the input side analog signal line in an abnormal state, and connects the image output unit to the output side analog signal line 8. To be connected. In FIG. 4, the input side is displayed as "from another image sensor" and the output side is displayed as "to the controller". Further, as the switching means 209, a switching circuit described in a second embodiment described later can be used.

The address setting section 210 is constituted by a dip switch, and an address for the controller 1 to specify the image sensor 2 is set. Operation means 211
Is a means for turning on and off the power. Further, when the operation unit 211 is turned off, the switching unit 209 connects the input side and the output side of the analog signal line 8 to bypass the image sensor 2 from the analog signal line 8.

FIG. 6 shows the configuration of the controller 1. The controller 1 includes a control unit 101 including an MPU and the like, and a power supply circuit 102. Controller 1
Each part in the inside is controlled by the control unit 101 and receives supply of power from the power supply circuit 102. The power supply circuit 102 includes a conversion circuit for converting an external AC voltage to a DC voltage and a battery. Also, a mode setting device 5 is connected.

The controller 1 is further provided with the following parts. The sensor monitoring circuit 103 includes the fire sensor 3,
This is the interface with the emergency button 4. Modem 10
4 is provided between the telephone line 6. The image sensor communication control unit 105 is connected to the image sensor 2 via the digital signal line 9. The video input / output control unit 106 is connected to the image sensor 2 via the analog signal line 8. The video input / output control unit 106 converts the video signal sent from the image sensor 2 into
It is distributed to the modem 104 and the monitor device 10 connected to the outside.

The display unit 107 normally displays the monitoring state of the monitoring area on the screen, and when an abnormality is detected, sounds a buzzer and displays the type of abnormality, the location where the abnormality occurred, and the like on the screen. . The display unit 107 is also used when setting the image sensor 2. The setting unit 108 is used at the time of initial setting or setting change of the image sensor 2. The general operation of the controller 1 will be described.

At the time of initial setting or setting change of the image sensor 2, an operator operates the monitor device 10 by using the image input / output control unit 1.
06, setting of the image sensor 2 (eg, height, angle, Sensitivity etc.). As described above, the controller 1 enables the setting of each image sensor 2 so that all the image sensors 2
Can be set. After the setting is completed, the monitor device 10 is removed from the controller 1.

The alert set mode or the alert release mode is set by the mode setting unit 5, and when the mode shift occurs, the image sensor communication control unit 105 and the digital signal line 9
A mode transition signal is transmitted to all the image sensors 2 via the. Fire sensor 3, emergency button 4 to sensor monitoring circuit 1
When an abnormal signal is input via the controller 03, the controller 1
Transmits data such as the type of abnormality, the location where the abnormality has occurred, and the time of occurrence to the security center device 7 via the modem 104 and the telephone line 6.

The controller 1 communicates with the image sensor communication control unit 105 via the digital signal line 9 a status calling signal,
A mode transition signal, an abnormal image transmission request signal, an abnormal image erasing signal, and the like are transmitted to the image sensor 2, and
Receives normal signals, abnormal signals, etc. Further, it receives a video signal from the image sensor 2 via the analog signal line 8 and the video input / output control unit 106.

When the image sensor 2 detects an abnormality, the controller 1 transmits the abnormality signal and the video signal received from the image sensor 2 to the security center device 7. The transmission and reception of signals between the controller 1 and the image sensor 2 and between the controller 1 and the security center device 7 have already been described with reference to FIG. Also,
In this example, an analog telephone line is used as the communication line, but a digital telephone line such as ISDN can be used. In this case, means for converting a video signal from an analog signal to a digital signal is required.

FIG. 7 shows the configuration of a part relating to the image monitoring system in the security center device 7. The security center device 7 includes a control unit 701 including an MPU or the like.
Are provided, and each part in the security center device 7 is controlled by the control part 701. A communication interface 702 for communicating with the controller 1 through the telephone line 6 is provided. The video signal and its related signal sent from the controller 1 are stored in the image information storage unit 703.
Note that the video signal is stored after being converted into digital data. This video signal includes an image at the time of occurrence of an abnormality, two frames before and seven subsequent frames. The data stored in the image information storage unit 703 includes an address of the image sensor 2 that has detected an abnormality, an abnormality occurrence time, a frame number of an image, and image data.

When the control unit 701 receives the abnormal signal,
The display unit 704 displays the occurrence of the abnormality, the name of the property in which the abnormality has occurred, the location of the abnormality, and the like, and displays an image when the abnormality has occurred on the monitor 704. The monitor 704 is connected to the control unit 701 via the image output unit 706. The controller checks the image on the monitor 704 to confirm the abnormal state. If the state cannot be sufficiently confirmed only by the image at the time of the occurrence of the abnormality, the frames subsequent to the image at the time of the occurrence of the abnormality can be sequentially or intermittently displayed.

Next, the detailed operation of the image sensor 2 will be described with reference to the flowcharts of FIGS. 8 and 9 show the abnormality detection logic of the image sensor 2. FIG.
The illustrated operation is started when the power of the image sensor 2 is turned on. In step S11, the image sensor 2 captures an image. This image is stored in the current image storage area 227. The current image storage area 227 stores this image and the previous two images.
Images of a total of three frames are sequentially stored and rewritten.

In step S12, the mode storage area 225
It is determined whether or not the alert set mode is set in the. If the mode is not the alert set mode (it is the alert release mode), the process returns to step S11. In the alert release mode, there is a legitimate user in the monitoring area, and there is no need to determine the presence or absence of a subsequent intruder. If the mode is the alert set mode, the process proceeds to step S13.

In step S13, it is determined whether a moving object has been detected. One example of this procedure has already been described with reference to FIG. When a moving object is detected, it is determined that an abnormality has occurred, and the process proceeds to step S14. If no moving object is detected, it is determined that no abnormality has occurred, and step S1 is performed.
Return to 1. In step S14, it is determined whether or not there is a free space in the abnormal image storage area 228 (FIG. 5) of the storage unit 220. If there is no free space in the abnormal image storage area 228, it means that an abnormality has already been detected,
At 24, the abnormal state is stored in the state storage area 224, and the process returns to step S11. If there is a vacancy, the process proceeds to step S15.

In step S16, the abnormal image storage area 22
8 stores the current image and the previous two frames of image. In step S17, the abnormal state is stored in the state storage area 224. In step S18, the image captured from the imaging unit 203 is stored in the current image storage area 227.

In step S19, the current image is stored in the abnormal image storage area 227. At this time, the image is stored after the already stored image. In step S20, it is determined whether or not the number of frames of the image stored in the abnormal image storage area 227 has reached 7, and if not, step S22.
Until 1 is added to n and the image of 7 frames is stored.
The operation of steps S17 to S19 is repeated. When the images of the seven frames are stored, the process proceeds to step S20, where n is reset to 0, and the process returns to step S11.

With the above-described abnormality detection logic, the image at the time of occurrence of the abnormality and the previous two images are stored in the abnormal image storage area 228.
A total of 10 frames of the image of the frame and the following 7 frames are stored. FIG. 10 is a flowchart showing the operation of the image sensor 2. This operation is started when the power of the image sensor 2 is turned on. Step S31
Then, the initial setting of the image sensor 2 is performed. This initial setting is performed in the controller 1 as described above, and the image sensor 2 receives data from the controller 1, stores the data in the parameter area 222, and
03 is set based on the stored data such as the height and angle. When the initialization is completed, the process proceeds to step S32.

In step S32, it is determined whether or not a status call signal has been received from controller 1. Upon reception, the current state stored in the state storage area 224, that is, a normal signal or an abnormal signal is transmitted in step S33. After transmitting the abnormal signal, the state storage area 224 is returned to the normal state. If the status call signal has not been received, step S33 is skipped.

In step S34, it is determined whether an abnormal image request signal has been received from the controller 1. Upon reception, in step S35, the abnormal image stored in the abnormal image storage area 228 is transmitted. If the abnormal image request signal has not been received, step S35 is skipped. In step S36, it is determined whether an abnormal image deletion signal has been received from the controller 1. Upon reception, in step S37, the abnormal image is deleted from the abnormal image storage area 228. If the abnormal image erasure signal has not been received, step S37 is skipped.

In step S38, it is determined whether or not a mode transition signal has been received from controller 1. Upon reception, in step S39, the set alert set mode or alert release mode is stored in the mode storage area 225, and the process returns to step S31. If an abnormal image erasure signal has not been received, step S39 is skipped and the process returns to step S31.

In the first embodiment described above, the plurality of image sensors 2 which are imaging devices are connected by one analog signal line 8 and one digital signal line 9, so that the wiring cost when installing the system is reduced. Can be reduced. In addition, since the video signal can be transmitted through the analog signal line 8, the security center device 7 can monitor with high-quality video.

(Embodiment 2) FIG. 11 shows the overall configuration of a second monitoring system to which the image monitoring system of the present invention is applied. A plurality of surveillance cameras 21 are installed at entrances and exits of the monitored building and other surveillance areas. The plurality of monitoring cameras 21 are connected in series to the monitoring device 22 by one control signal line 23 (digital signal line) and one video signal line 24 (analog signal line). The monitoring device 22 is provided with a monitoring device 25, and sequentially switches and displays images captured by each monitoring camera.

Each monitoring camera 21 is provided with a control signal terminal 322 connected to the control signal line 23 and terminals 311 and 312 connected to the video signal line 24. Video signal line 24
Is divided into a monitoring device side and a terminal side in each monitoring camera 21, and a monitoring device side terminal 311 of a different monitoring camera is
By connecting the terminal 312 and the terminal 312, a plurality of monitoring cameras 21 are connected in series to the monitoring device 22 by one video signal line 24. As the control signal line 23, a twisted pair line for transmitting a digital signal is used, and as the video signal line 24, a coaxial cable (75Ω) for transmitting an analog signal is used.

FIG. 12 shows the internal configuration of the monitoring camera 21. The output signal of the CCD camera 313 as the imaging means is
The video signal is processed by the video signal processing unit 314 and converted into a video signal. This video signal is connected to the monitoring device side terminal 311 through the video switch 315, the driver 316, and the first relay 317. Note that an audio signal detected by a microphone can be superimposed on this video signal.

The terminal 312 is connected to the third relay 319.
Is connected to the monitoring device side terminal 311 through the
Is connected to the video switch 315 through the relay 318 of FIG. Also, the second relay 318 and the video switch 31
The connection point 5 is grounded via a 75Ω termination resistor 320. Here, the first and second relays 317 and 318 are turned on when power is supplied, and turned off when power is not supplied. The third relay 319 is turned off when power is supplied. , A relay that is turned on when power is not supplied. The video switch 315 is connected to the control unit 32
A switch that performs switching under the control of No. 1 and switches between a state in which the output side of the video signal processing unit 314 is connected to the driver 316 and a state in which the output side of the second relay 318 is connected to the driver 316.

The receiving section 323 is connected to the control signal terminal 322, and the output signal of the receiving section 323 is input to the control section 321. Next, the operation of the monitoring system will be described with reference to FIGS. When power is not supplied to the monitoring camera 21, the third relay 319 is turned on and the first relay 319 is turned on.
Also, since the second relays 317 and 318 are turned off, the terminal 312 and the monitoring device terminal 311 are short-circuited, and the internal circuit of the monitoring camera 21 is disconnected from the video signal line 24. Accordingly, the video signal line 24 bypasses the monitoring camera 21. Therefore, when the power is turned off, the monitoring camera 21 has no effect on the transmission of the video signal between the other monitoring cameras 21 and the monitoring device 22.

When power is supplied to the monitoring camera 21, the third relay 319 is turned off, and the first and second relays 31 are turned off.
7, 318 are turned on. In addition, the control unit 321 switches the video switch 315 to a state in which the output side of the second relay 319 and the input side of the driver 316 are connected. As a result, when a video signal is transmitted from the surveillance camera 21 on the terminal side from the surveillance camera 21, the video signal is input from the terminal 312 through the video signal line 24, the second relay 318, and the terminal resistor 320. , Video switch 315, driver 316, first relay 31
7. The video signal is transmitted to the video signal line 24 through the monitoring device side terminal 311.

The monitoring device 22 sequentially operates the monitoring cameras 21
To the control signal line 23
Through. This command does not request two or more surveillance cameras to transmit video signals at the same time. In each monitoring camera 21, the reception signal input from the control signal line 23 and the control signal terminal 322 is
3 and outputs the command to the control unit 321. The control unit 321 analyzes the command, and if the command is a command for its own surveillance camera and a command for sending a video, the video switch 315 is switched to connect the video signal processing unit 314 to the driver 316. Switch to the state where

Thus, the video signal of the video captured by the CCD camera 313 is transmitted from the monitoring device side terminal 311 to the video signal line 24 through the video signal processing unit 314, the video switch 315, the driver 316, and the first relay 317. Is done. At this time, power is not supplied to the surveillance camera 21 existing between the surveillance camera 21 and the surveillance device 22 that transmits the video signal, or the surveillance device 23 requests the surveillance device 23 to transmit the video signal. The command has not been sent. For this reason, the video signal transmitted to the video signal line 24 is transmitted to the monitoring device 22 without any trouble from the monitoring camera 21 in the middle of the video signal line 24.

The monitoring device 23 monitors the monitoring area while watching the video displayed on the monitoring device 25. In the second embodiment described above, a plurality of surveillance cameras 2
1 is connected by one control signal line 23 and one video signal line 24, so that the number of signal lines is reduced and the wiring cost when the system is installed can be reduced. In addition, since the video signal can be transmitted as an analog signal, the monitoring device 22 can monitor with high-quality video.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a first monitoring system to which an image monitoring system according to the present invention is applied.

FIG. 2 is a method 1 for detecting an abnormality from an image of an image sensor.
The figure explaining an example.

FIG. 3 is a time chart for explaining the operation of the image monitoring system in FIG. 1;

FIG. 4 is a diagram showing a configuration of the image sensor of FIG. 1;

FIG. 5 is a diagram showing contents of a storage unit in the image sensor of FIG. 4;

FIG. 6 is a diagram showing a configuration of a controller in FIG. 1;

FIG. 7 is a diagram showing a configuration of a security center device of FIG. 1;

FIG. 8 is a flowchart (part 1) illustrating an abnormality detection logic of the image sensor of FIG. 4;

FIG. 9 is a flowchart (part 2) illustrating abnormality detection logic of the image sensor of FIG. 4;

FIG. 10 is a flowchart showing the operation of the image sensor of FIG. 4;

FIG. 11 is a diagram showing an overall configuration of a second monitoring system to which the image monitoring system of the present invention is applied.

FIG. 12 is a diagram showing an internal configuration of the monitoring camera in FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Controller 101 ... Control part 102 ... Power supply circuit 103 ... Sensor monitoring circuit 104 ... Modem 105 ... Image sensor communication control part 106 ... Video input / output control part 107 ... Display part 108 ... Setting means 2 ... Image sensor 201 ... Control means 202 ... Power supply 203 ... Imaging means 204 ... Infrared light projecting means 205 ... Image processing means 206 ... Display means 207 ... Communication means 208 ... Image output means 209 ... Switching means 210 ... Address setting unit 211 ... Operation means 220 ... Storage means 221 ... Program Area 222 Parameter area 223 Work area 224 State storage area 225 Mode storage area 226 Reference image storage area 227 Current image storage area 228 Abnormal image storage area 3 Fire sensor 4 Emergency button 5 Mode setting device 6. Telephone line 7. Security center equipment 70 ... Control unit 702 ... Communication interface 703 ... Image information storage unit 704 ... Monitor 705 ... Operation unit 706 ... Image output unit 8 ... Analog signal line 9 ... Digital signal line 10 ... Monitor device 21 ... Monitoring camera 22 ... Monitoring device 23 ... Control Signal line 24 ... Video signal line 25 ... Monitor device 311 ... Monitor device side terminal 312 ... Terminal side terminal 313 ... CCD camera 314 ... Video signal processing unit 315 ... Video switch 316 ... Driver 317,318,319 ... First to third Relay 320, terminating resistor 321, control unit 322, control signal terminal 323, receiving unit

Claims (1)

[Claims] 1. An image monitoring system for connecting a plurality of imaging devices for capturing an image of a monitoring area to a monitoring device, wherein the plurality of imaging devices are serially connected to the monitoring device by a control signal line and a video signal line. An imaging unit configured to capture an image of a monitoring area; a control signal receiving unit connected to the control signal line to receive a control signal from the monitoring device; and a video signal obtained from the imaging unit. And a video signal line connected to the video signal transmission unit, the video signal line is divided into a video signal line on the monitoring device side and a video signal line on the terminal side, and the video signal line on the monitoring device side Switching means for switching between a state in which the video signal line on the terminal side and the video signal line on the monitoring device side are connected to the video signal transmission means; Is normally switched to a state in which the video signal line on the monitoring device side and the video signal line on the terminal side are connected, and when the receiving unit receives a command for transmitting its own video, the monitoring device side A video signal line and control means for switching the video signal transmission means to a connected state.