JP2000194971A - Image monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably pick up the image of a monitored area by excluding influence by the illumination of the infrared light projecting means of another image pickup device and to make the existence/absence of abnormal occurrence judgeable with high accuracy by making an image pickup device start an infrared light projecting means with a prescribed time difference. SOLUTION: Each image sensor (image pickup device) 2 receives a synchronous command with a communicating means 207. A controlling means 201 calculates the delay time at a time when the synchronous command is inputted based on a number set to an address setting part 210 and starts an infrared light projecting means 204 by delaying for the time. The means 201 makes infrared light projected and makes an image picking up means 203 photograph a one-frame image. After that, it makes repeated light projection and photographing in every 0.5 second. In each image sensor 2, the means 204 respectively projects infrared light at different timing, and plural infrared light projecting means 204 do not simultaneously project infrared light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image monitoring system in which a plurality of image pickup devices provided with infrared light projecting means are connected to a monitor so as to enable photographing even in a dark monitor area.

[0002]

2. Description of the Related Art Conventionally, there has been practically used an image monitoring system in which a plurality of image pickup devices continuously photograph entrances and exits of a building and other monitoring areas and transmit the photographed images to a monitoring center located at a remote place through the monitoring device. Has been Also,
In the imaging device or the monitoring device, based on the captured image, intruder, to determine the occurrence of abnormalities such as fire,
An image monitoring system that sends an image at the time of occurrence of an abnormality to a monitoring center when an abnormality is detected has been put to practical use.

In these conventional image monitoring systems, each imaging device captures an image by capturing an image of a monitoring area at a predetermined time interval. Further, each imaging device has an infrared light projecting means, and when the monitoring area is dark, the infrared light projecting means is activated at the predetermined time interval to illuminate the monitoring area and perform photographing.

[0004]

This time interval is determined by an internal clock incorporated in each imaging means. For this reason, when a plurality of imaging devices are installed in a place close to the monitoring area (for example, in the same room), the monitoring area to be imaged by the imaging apparatus simultaneously emits two infrared rays due to a shift in the internal clock of each imaging apparatus. There is a case where a bright image is captured by being illuminated by the light means, or a relatively dark image is captured without the two infrared light projecting means being simultaneously illuminated.

In this case, when the occurrence of an abnormality is determined based on the image, there is a problem that if the brightness of the image captured by the imaging device changes between the preceding and following images, the accuracy of the determination decreases. The present invention, in an image monitoring system including a plurality of imaging devices having infrared light projection means, it is possible to eliminate the influence of illumination of the infrared light projection means of another imaging device, to perform a stable imaging of the monitoring area, It is an object of the present invention to accurately determine whether an abnormality has occurred.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. The image monitoring system according to the present invention is configured by connecting a plurality of imaging devices that capture images of a monitoring area to the monitoring device. In the present invention, the monitoring device has a communication unit that transmits a synchronization control signal to the imaging device every predetermined time. This synchronization control signal can be transmitted to the imaging device by a broadcast method.

[0007] Further, the image pickup apparatus includes an image pickup means for taking an image of a monitor area, an infrared light projecting means for projecting infrared rays to the monitor area, a receiving means for receiving a synchronization control signal from the monitor apparatus, and an image pickup means. And a control means for activating the infrared light projecting means with a predetermined time difference after receiving the synchronization control signal.

According to the present invention, since each imaging device can start the infrared light emitting means with a different time difference after receiving the synchronization control signal, a plurality of imaging devices are arranged in the same monitoring area. Even in such a case, the same monitoring area can be prevented from being simultaneously illuminated by a plurality of infrared light projecting means. Therefore, the image captured by the imaging device can always be captured at a constant brightness,
It is possible to determine with high accuracy whether an abnormality has occurred based on an image.

Further, the monitoring device transmits a reset signal to a specific one of the plurality of imaging devices and then newly transmits a synchronization control signal to all the imaging devices by the communication means. Can be. Accordingly, when a failure occurs in one of the plurality of imaging devices and communication with the monitoring device becomes impossible, or when an imaging device is added, the monitoring device resets the imaging device. After that,
The synchronization control signal is transmitted to all imaging devices. Thus, the imaging device that has recovered from the failure and the added imaging device can continue shooting the monitoring area without simultaneously emitting infrared rays, similarly to the other imaging devices.

Further, in the present invention, the image pickup apparatus has an address setting unit for identifying itself, and a predetermined time difference can be obtained by using the address set by the address setting unit. . The addresses of the imaging devices are set to different values. Therefore, by calculating the time difference from this address, a different predetermined time can be set for each imaging device.

Further, according to the present invention, each of the imaging devices has a time measuring means, and after the control means activates the infrared light emitting means, the infrared light emitting means is activated at a time interval measured by the time measuring means. Can be. In this case, each imaging device activates the infrared light projecting device by its own time counting device until receiving the next signal after receiving the synchronization control signal from the monitoring device. Before the clock shift of the timekeeping means for each imaging device occurs, the next synchronization control signal is transmitted from the monitoring device. According to this, the monitoring device does not need to transmit the synchronization control signal at each timing when each imaging device performs shooting, and can reduce the load of the communication process.

[0012]

FIG. 1 shows the overall configuration of an image monitoring system to which the present invention is applied. A controller 1 is installed in a building to be monitored, and a plurality of image sensors 2A, 2B,..., A fire sensor 3, an emergency button 4, and a mode setting device 5 are connected to the controller 1. Controller 1
Via a telephone line 6 as a communication line, it is connected to a security center device 7 installed at a remote monitoring center.

Here, the overall operation of the image monitoring system of FIG. 1 will be briefly described. The mode setting device 5 sets the image monitoring system to the alert release mode or the alert set mode. When any of the sensors detects an abnormality in the alert set mode, 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. In addition, since the detection method and transmission method of these abnormal signals are well known in the technical field, detailed description will be omitted.

When the security center device 7 receives the abnormal signal and the abnormal image, the security center device 7 displays the abnormal data such as the type and location of the abnormality and the abnormal image on the monitor. The monitoring center controller checks this display and takes necessary measures. A plurality of image sensors 2 are installed in the building, and photograph a monitoring area including a monitoring target such as a window or a door. Also, the image sensor 2
Determines from the obtained image whether there is an abnormality such as intrusion. Various methods have been proposed as a method for determining the presence / absence of this abnormality, and any means can be adopted.
According to the present invention, the reference image is stored in advance by the image sensor, and the difference between the reference image and the current image captured by the imaging unit is determined.

FIG. 2 shows the configuration of the image sensor 2. The image sensor 2 includes a control unit 2 including a CPU or the like.
01 and a power supply 202 are provided. Each part inside the image sensor 2 is controlled by a control unit 201 and a power supply 202.
Power supply from. The power supply 202 includes a conversion device that converts AC power 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 storage means 220 is connected to the control means 201. The storage means 220 has a program, a parameter, and a program for causing the image sensor 2 to execute a predetermined operation.
A status signal indicating whether the current state of the monitoring area is normal or abnormal, a security mode in which the monitoring area is set, and the like are stored. The storage unit 220 further includes a reference image storage area, a current image storage area, and an abnormal image storage area as areas for storing images captured by the imaging unit 203.

The monitoring means 203 for photographing the monitoring area is
It is configured by a CD camera or the like, and has sensitivity from the visible region to the infrared region. An infrared light projecting unit 204 is provided, and emits infrared light to the monitoring area when it becomes dark such as at night. The image processing unit 205 compares the current state image stored in the storage unit 220 with the reference image and determines whether an abnormality has occurred.

The display means 206 is constituted by an LED, and is turned on when an abnormality is detected, turned off when no abnormality is detected, and displays the presence or absence of 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. The image output unit 208 is an interface for outputting an image when an abnormality has occurred.
09 and the analog signal line 8.

The analog signal line 8 is, as shown in FIG.
The controller 1 and each image sensor 2 are connected in series.
The switching means 209 of the image sensor 2 connects the input side and the output side of the analog signal line 8 when normal, disconnects the analog signal line on the input side when abnormal, and connects the image output means to the analog output line 8 on the output side. To be connected. In FIG. 2, the input side is displayed as "from another image sensor" and the output side is displayed as "to the controller".

The address setting section 210 is constituted by a rotary switch, and sets an address for the controller 1 to specify the image sensor 2. This address is used for delay processing of the infrared light projecting means 204 of each image sensor 2 when a synchronization command described later is broadcast. The operation unit 211 is a unit for turning on / off the power. 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. 3 shows the configuration of the controller 1. The controller 1 includes a control unit 101 including a MPU and the like and a power supply circuit 102. Controller 1
Are controlled by the control unit 101, and the power supply circuit 1
02 is supplied with electric power. The power supply circuit 102 includes a conversion circuit for converting an external AC power supply 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 is an interface with the fire sensor 3 and the emergency button 4. Modem 104
Is provided between the telephone line 6. The image sensor communication control unit 105 is connected to the image sensor 2 via data and signal lines 9. The video input / output control unit 106 is connected to the image sensor 2 via the analog signal line 8. This video input / output control unit 10
Reference numeral 6 distributes the video signal sent from the image sensor 2 to the modem 104 and the monitor device 10 connected to the outside.

The display unit 107 normally displays the monitoring status 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 for setting the image sensor 2. The synchronization control signal will be described with reference to FIG.

The controller 1 activates a clock means incorporated in the control unit 101 and broadcasts a synchronization control signal (hereinafter referred to as a “synchronization command”) on the digital signal line 9 every minute, for example. In each image sensor 2, the synchronization command is received by the communication unit 207 and input to the control unit 201. The control means 201 once resets the timing at which the infrared light projecting means 204 has been activated up to now. Then, the delay time is calculated based on the number set in the address setting unit 210 from the input time point of the synchronization command, and the infrared light emitting unit 204 is activated with a delay of this time from the synchronization command.

The calculation method of the delay time is as follows.
Now, it is assumed that the infrared light emitting unit 204 emits infrared light for 27 msec for one frame of the image sensor 2. The control means 201 multiplies its own address number by 54 ms for a double frame, and sets a time obtained by subtracting 54 ms as its own delay time. That is, the delay time of the image sensor 2A is 0 ms, the image sensor 2B is 54 ms, the image sensor 2C is 54 ms × 2,.
Seconds × 7.

After inputting the synchronization command, the control means 201 activates the infrared light projecting means 204 after the delay time, emits infrared light for 27 msec, and takes one frame of image. After that, the light emission and the photographing for one frame are repeatedly performed every 0.5 seconds by the timing means built in the control means 201. This cycle is repeated until the next synchronization command is broadcast on the digital signal line 9.

Thus, in each of the image sensors 2 connected to the controller 1, the infrared light projecting means 204 emits infrared light at different timings, and simultaneously, the infrared light projecting means 204 emits infrared light. There is no light. Therefore, even if a plurality of image sensors 2 are arranged in the same monitoring area, the infrared rays emitted to the monitoring area do not affect each other. That is, the image sensor 2
Does not suddenly change due to the emission of infrared light from another image sensor, so that there is no erroneous determination of the presence or absence of an abnormality.

Further, as described above, the control means 201
When the synchronization command is input, the infrared projection means 2
04 is reset, and the delay time is calculated again. The reason why the synchronization command is periodically broadcast in this way is to prevent the infrared light projection from overlapping even if the clock means incorporated in the control means 201 is shifted.

Although the numerical values at each time in the above described example can be arbitrarily changed, the maximum number of image sensors 2 that can be connected to one controller 1 in the above example is eight. Next, a case where a reset signal is output from the controller 1 will be described. Now, the image sensor 2 set as the first in the address setting unit 210
It is assumed that A causes a communication error with the controller 1. In this case, the controller 1 controls the image sensor 2A
, A reset signal is transmitted periodically until restoration is confirmed. When the communication between the controller 1 and the image sensor 2A is restored, the image sensor 2A transmits an acknowledgment signal (ACK) to the controller 1 for the reset signal transmitted periodically from the controller 1. Thereafter, the image sensor 2A that has received the reset signal for itself performs a predetermined initialization process.

Thereafter, the controller 1 broadcasts a synchronization command to the digital signal line 9 after a lapse of a predetermined time (for example, 10 seconds). The predetermined time at this time is for checking the time required for the above-described initialization processing of the image sensor 2. Thereafter, the control means 201 of each image sensor 2 starts the infrared light projecting means based on the newly broadcasted synchronization command.

In the above example, the case where a communication error has occurred between the controller 1 and the image sensor 2 has been described. However, the same can be applied to the case where the image sensor 2 is newly added and installed. . In this case, data is downloaded from the controller 1 to the added image sensor 2A. When the power of the image sensor 2A is turned on, the controller 1 transmits a reset signal to the image sensor 2A, and then broadcasts a synchronization command.

In the above example, the image sensor 2 determines whether the image is normal or abnormal. However, the determination may be performed by the controller 1. In this case, the controller 1 stores the reference image for each image sensor 2 and compares the video signal of the current image transmitted from the image sensor 2 with the stored reference image to determine whether the image is normal or abnormal. judge.

[0033]

According to the present invention, even when a plurality of imaging devices are installed in a close place such as the same room, a plurality of infrared rays do not overlap and emit light, so that a monitoring area for imaging is not required. The brightness does not fluctuate. Therefore, it is possible to accurately determine whether an abnormality has occurred.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration of an imaging device in FIG. 1;

FIG. 3 is a diagram showing a configuration of a controller in FIG. 1;

FIG. 4 is a time chart for explaining the timing of a synchronization control signal according to the present invention.

[Description of Signs] 1 ... Controller 101 ... Control unit 102 ... Power supply circuit 103 ... Sensor monitoring circuit 104 ... Modem 105 ... Image sensor communication control unit 106 ... Video input / output control unit 107 ... Display unit 108 ... Setting means 2 ... Image sensor (Imaging device) 201 ... Control means 202 ... Power supply 203 ... Imaging means 204 ... (Infrared) light emitting 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 3 ... fire sensor 4 ... emergency button 5 ... mode setting device 6 ... telephone line 7 ... security center device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiki Kobayashi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. No. 1 F-term in Hitachi Research Laboratory, Hitachi, Ltd. F-term (reference) GG39 GG43 GG45 GG46 GG52 GG68 GG73 GG78 HH03 HH08 HH10 HH12 HH13 5C087 AA02 AA03 AA09 AA11 AA23 AA32 AA42 BB03 BB12 BB32.

Claims (5)

[Claims] 1. An image monitoring system for connecting a plurality of imaging devices that capture a monitoring area to a monitoring device, wherein the monitoring device has a communication unit that transmits a synchronization control signal to the imaging device every predetermined time, An imaging unit that captures the monitoring area; an infrared projection unit that emits infrared light to the monitoring area; a receiving unit that receives the synchronization control signal from the monitoring apparatus; An image monitoring system comprising: a video signal transmitting unit that transmits a video signal; and a control unit that activates the infrared light projecting unit with a predetermined time difference after receiving the synchronization control signal. 2. The image monitoring system according to claim 1, wherein the monitoring device transmits the synchronization control signal to the imaging device by a broadcast method. 3. The monitoring device transmits a reset signal to a specific imaging device among the plurality of imaging devices and receives a confirmation signal for the reset signal from the plurality of imaging devices, and then newly monitors all of the plurality of imaging devices. The image monitoring system according to claim 1, wherein the synchronization control signal is transmitted to an imaging device. 4. The image monitoring apparatus according to claim 1, wherein the imaging device has an address setting unit for identifying itself, and obtains the predetermined time difference using an address set by the address setting unit. . 5. The image pickup apparatus further includes a timing unit,
After the control means activates the infrared light projecting means,
2. The image monitoring system according to claim 1, wherein the infrared light projecting means is activated at a time interval measured by the time measuring means.