JP2000222646A - Monitoring camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily deal with an unauthorized action by detecting that the view of an image pickup means is interrupted and outputting an alarm. SOLUTION: A monitoring camera 1 image-picks up the picture of a monitoring area by an image pickup part 10 and outputs a picture signal to a signal transmission part 12 through an interruption detector 13. The interruption detection part 13 takes in the picture from the image pickup part 10 and calculates a luminance value (256 steps in the gray levels of luminance, for example) at every picture element of the obtained picture. The previously decided number of picture elements, which is not less than the prescribed luminance value, is calculated and the calculated number of picture elements is compared with the previously decided number of picture elements. When the calculated number of picture element is smaller than the previously decided number of picture elements, the take-in of the picture is continued. When it is larger, the interruption of a view is judged and an abnormal signal is transmitted to a signal transmission part 12. When a controller receives an interruption signal, a control part outputs an alarm signal to an alarm device. The alarm device transmits the alarm to a remote alarm center through a telephone line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveillance camera system in which a surveillance camera is installed in places such as stores and companies where people come and go, and monitors and records the actions of suspicious persons.

[0002]

2. Description of the Related Art Conventionally, a surveillance camera has been installed in a store or an entrance, which is a surveillance place, and an image transmitted from the surveillance camera is displayed on a monitor at a surveillance center, or this image is recorded for ex-post monitoring. Surveillance camera systems as evidence are known.

[0003]

However, in the above-mentioned conventional surveillance camera system, for example, a fraudster cannot illuminate the surveillance camera with strong illumination, spray a spray, or cover the surveillance camera and take an image. After doing so, a crime may be committed. If an observer constantly monitors the monitor, he / she can notice such misconduct, but if he only records images from surveillance cameras, he cannot record images of criminal acts. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a surveillance camera system capable of detecting when a visual field of a surveillance camera is obstructed and outputting an alarm. .

[0005]

In order to solve the above-mentioned problems and achieve the above-mentioned object, a surveillance camera system according to the present invention comprises a disturbance detecting means for detecting whether or not a visual field of an image pickup means is disturbed. And alarm means for outputting an alarm based on the detection result of the interference detection means.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a surveillance camera system according to the present invention will be described with reference to FIGS. FIG.
FIG. 1 is a configuration diagram of a surveillance camera system according to the present embodiment. 1
Reference numerals A to 1D denote surveillance cameras for imaging a surveillance area. 2
Is connected to the monitoring cameras 1A to 1D via a coaxial cable 5 by a controller, and receives and processes images and audio signals transmitted from the monitoring cameras 1A to 1D. Reference numeral 3 denotes a time lapse video, which is connected to the controller 2 via a coaxial cable 6, receives an image and an audio signal transmitted from the controller 2, and performs recording and recording. Reference numeral 4 denotes an alarm device that monitors improper actions on the surveillance camera 1 and sends an alarm to a remote security center (not shown) when an abnormality occurs.

FIG. 2 is a functional block diagram of the monitoring camera 1. An imaging unit 10 includes a lens, a CCD, and the like, and captures an image in the monitoring area and converts the captured image into a predetermined image signal. Reference numeral 11 denotes a sound collecting unit which is constituted by a microphone and collects sound in the monitoring area and converts the sound into a predetermined sound signal. Reference numeral 12 denotes a signal transmission unit, and the imaging unit 10 and the sound collection unit 11
Is converted into a predetermined output signal and transmitted to the controller 2 via the coaxial cable 5. Reference numeral 13 denotes a disturbance detection unit that detects a luminance value of an image captured by the imaging unit.

FIG. 3 is a functional block diagram of the controller 2. Reference numeral 20 denotes an image processing unit which processes image signals received from the monitoring cameras 1A to 1D via the coaxial cables 5A to 5D and synthesizes them as one image divided into four. Further, it detects whether or not the image signal is normally received. Reference numeral 21 denotes an image output unit which sends out the quartered image synthesized by the image processing unit 20 to the time lapse video 3 via the coaxial cable 6.
Reference numeral 22 denotes a C operation unit which includes switches and the like, and allows an operator to perform various setting operations of the controller 2. Reference numeral 23 denotes a C control unit including a CPU and the like, which is connected to each unit and controls operation. Reference numeral 24 denotes an I / F unit configured by, for example, RS232C, which relays a signal from a C authentication unit 25 described later. 25
Is a C authentication unit composed of, for example, a card reader, and checks the qualification of an operator who operates the controller 2. 2
Reference numeral 6 denotes a C power supply unit that supplies power to each unit of the controller 2. Reference numeral 27 denotes a C power supply cutoff detecting unit which, when the power supply of the C power supply unit 26 is cut off, detects this and switches a relay contact (not shown). Reference numeral 28 denotes a C alarm output unit which outputs an alarm signal to the alarm device 4 when the image signal from the monitoring cameras 1A to 1D is interrupted by the image processing unit 20, for example.

FIG. 4 is a functional block diagram of the time lapse video 3. A recording unit 31 receives the four-divided image signal received from the controller 2 and records it on a video tape. Reference numeral 32 denotes a T operation unit for performing operations such as starting and stopping recording, timer operation, and insertion / removal of a video tape. Reference numeral 33 denotes a T control unit composed of a CPU and the like, which is connected to each unit to perform operation control. Reference numeral 34 denotes an I composed of, for example, RS232C.
The / F section relays a signal from a T authentication section 35 described later. Numeral 35 denotes a T authentication unit composed of, for example, a card reader, which checks the qualification of the operator who operates the time lapse video 3. Reference numeral 36 denotes a T power supply unit, and a time lapse video 3
Power is supplied to each section. Reference numeral 37 denotes a T power cutoff detecting unit.
When the power of the power supply unit 36 is cut off, this is detected and a relay contact (not shown) is switched. Reference numeral 38 denotes a T alarm output unit, which outputs an alarm signal to the alarm device 4 when the image signal from the controller 2 to the recording unit 31 is interrupted, for example.

Next, the operation of detecting an obstruction of visual field to the surveillance camera 1 and outputting an alarm in the surveillance camera system according to the present invention will be described with reference to FIG. First,
Turn on the power of each part of the surveillance camera system. Each of the monitoring cameras 1A to 1D captures an image of the monitoring area by the imaging unit 10
And outputs an image signal to the signal transmission unit 12 via the interference detection unit 13. In the interference detection unit 13, step S1
Captures an image from the imaging 10. Luminance value for each pixel of the image obtained in step S2 (256 gradations of luminance)
Is calculated. In step S3, the number of pixels having a predetermined brightness value or more is calculated. The number of pixels calculated in step S4 is compared with a predetermined number m of pixels. When the calculated number of pixels is smaller than m, the process returns to step S1, and
If it is larger, the process proceeds to step S5. In step S5, it is determined that the visual field disturbance is abnormal, and an abnormal signal is transmitted to the signal transmission unit 12.

In this embodiment, the brightness value is calculated for each pixel of the obtained image. However, the brightness value may be calculated for a pixel block composed of predetermined pixels. In addition,
In this case, the brightness value of the pixel block may be obtained by adding the brightness values of the predetermined pixels and dividing by a predetermined number of pixels. Then, for example, when a strong illumination such as a searchlight is applied to the imaging unit 10, the luminance value of each pixel of the image becomes large. Calculate the number.

If the camera is covered with a cover or the like, the luminance value of each pixel of the image becomes small. Therefore, the calculation is made such that the predetermined luminance value or more in step S3 is equal to or less than the predetermined luminance value. When the obstruction detecting unit 13 detects the obstruction of the visual field, the signal transmitting unit 12 converts the obstruction into a predetermined alarm signal,
A to 5D. The image of the monitoring area captured by the imaging unit 10 and output to the signal transmission unit 12 via the interference detection unit 13 is, for example, converted into an NTSC image signal and transmitted through the coaxial cables 5A to 5D. It is sent to the controller 2. The image processing unit 20 of the controller 2
The received four images of the surveillance cameras 1A to 1D are created as one image divided into four and output to the time lapse video 3 by the image output unit 21. The image processing unit 20 also receives the interference detection signals of the monitoring cameras 1A to 1D via the coaxial cables 5A to 5D. Then, when the interference detection signal is received, the C control unit 23 outputs an alarm signal to the alarm device 4 at the C alarm output unit 28. Upon receiving the alarm output from the controller 2, the alarm device 4 sends an alarm to a remote security center (not shown) through a telephone line or the like.

As described above, the surveillance camera system according to the present embodiment can detect an obstructive action on the imaging unit 10 of the surveillance camera 1 and output an alarm. Can be dealt with.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a surveillance camera system

FIG. 2 is a functional block diagram of a surveillance camera.

FIG. 3 is a functional block diagram of a controller.

FIG. 4 is a functional block diagram of a time-lapse video.

FIG. 5 is a flowchart for detecting a visual field obstruction act.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Surveillance camera 13 ... Obstruction detection part 2 ... Controller 3 ... Time lapse video

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 7/18 G01V 9/04 S

Claims (4)

[Claims] 1. An image pickup means for picking up an image of a monitoring area, an interference detection means for detecting whether or not the visual field of the image pickup means is obstructed, and an alarm means for outputting an alarm based on the detection result of the interference detection means. Surveillance camera system having 2. The surveillance camera system according to claim 1, wherein said interference detection means detects that a predetermined area of an image having a predetermined luminance value or more has reached a predetermined number or more. 3. The surveillance camera system according to claim 1, wherein said disturbance detection means detects that a predetermined area of the image having a predetermined luminance value or less has reached a predetermined number or more. 4. The surveillance camera system according to claim 2, wherein the predetermined area of the image is a pixel.