JP2003153245A - Method for detecting abnormity of supervisory camera in supervisory system adopting still picture transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can automatically detect the abnormity of a supervisory camera in a supervisory system adopting the still picture transmission system so as to allow a monitor to report the abnormity. SOLUTION: In the supervisory system adopting the still picture transmission system comprising: a first supervisory apparatus 1 that transmits a still picture of a supervisory object photographed by the supervisory camera 6 as image data subject to compression processing; and a second supervisory apparatus 2 that receives the image data from the first supervisory apparatus 1 via a communication line 8, applies expansion processing to the data to decode the processed data and allows a display device 16 to display the still picture of the supervisory object for supervising the object, when a lens of the supervisory camera 6 receives photographing disturbance such as blowing of a spray and a camera cable is broken, the system allows the second supervisory apparatus to display/alert the occurrence of the abnormity in the photographing by the supervisory camera 6.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for detecting an abnormality of a monitoring camera in a monitoring apparatus of an image transmission system constituting a security system. 2. Description of the Related Art As shown in FIG. 2, a monitoring apparatus based on an image of a conventional image transmission system used in a security system includes a monitoring apparatus 201 on a transmitting side and a monitoring apparatus 202 on a receiving side. The monitoring device 202 is installed at the place where the observer resides. Still images captured by the monitoring camera 106 in the monitoring device 201 on the transmission side are stored in the frame memory 105.
The image data stored in the frame memory 105 is
The CPU 101, which controls the monitoring device 201, a ROM 102, which stores an image processing program, a RAM 103, which is a memory required for each processing, a compression processor 104 for high-speed operation, etc. The unit 107 transmits image data to the monitoring device 202 on the receiving side via the communication line 108. The synchronization detection unit 109 detects a synchronization signal included in a video signal from the monitoring camera 106 and constantly monitors the synchronization signal. [0003] In the monitoring apparatus 202 on the receiving side, image data input via the communication control unit 117 is temporarily stored in a RAM.
113, the CPU 111, the ROM 112,
The image data stored in the RAM 113 is subjected to decompression processing by the arithmetic processor 114 or the like, and the generated still image is displayed on the display device 116 via the frame memory 115. Was confirmed. [0004] The monitoring device 20 on the transmission side
If the lens of the surveillance camera 106 constituting the camera 1 is disturbed by spraying or adhesion of a tape to the lens, the image of the object to be monitored is uniformly dark and flat. When the image is compressed, the data amount of the image data becomes much smaller than the compressed data amount in the normal state. Therefore, it is stored in the arithmetic processor 104 that the data amount has become smaller than the preset data amount threshold value. The monitoring device 20 on the receiving side detects that a certain threshold value detecting unit has detected an abnormality in the photographing by the monitoring camera 106.
2 displays and alerts. Also, the monitoring camera 106
When the cable is disconnected, the synchronization signal included in the video signal from the camera is interrupted. The synchronization signal detection unit 109 that detects the synchronization signal is transmitted to the monitoring device 2 on the transmission side.
01, the receiving-side monitoring device 202 displays and warns that an abnormality has occurred in the cable of the monitoring camera 106 when the synchronization signal detection unit 109 detects the absence of a synchronization signal. [0005] The monitoring apparatus 201 on the transmission side
When the cable of the surveillance camera 106 in
This means that an all-black image has been captured inside the monitoring device 201, and the compression of this all-black image minimizes the amount of image data. Monitoring device 20 on the transmission side
1 includes a camera lens 1
Since the threshold value detecting unit for detecting the abnormality of the number 06 is provided, if the minimum value detecting unit capable of detecting the minimum value of the known data amount smaller than the threshold value is provided in the arithmetic processor 104, the disconnection of the cable can be easily detected. Yes, the synchronization signal detection unit 109
Becomes unnecessary. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a still image transmission type monitoring apparatus according to the present invention. The first monitoring device 1 on the transmitting side controls the monitoring device 1
PU1, ROM2 storing communication processing and image processing programs, RAM comprising memory required for each processing
3. High-speed operation processor 4 storing a threshold value detection unit and a minimum value detection unit; frame memory 5 storing image data; monitoring camera 6 for photographing a still image; communication control unit 7 controlling communication line 8 It consists of. The second monitoring device 2 on the receiving side includes a CPU 11 for controlling the monitoring device 2, a ROM 12 for storing communication processing and image processing programs, a RAM 13 comprising a memory required for each processing, and a high-speed operation. Memory processor 14 for storing image data
5, a display device 16 for displaying an image, an alarm device 18 for warning an abnormality of the monitoring camera 6, and a communication control unit 17 for controlling the communication line 8. In the first monitoring device 1 on the transmitting side, image data of a still image of the monitored object captured by the monitoring camera 6 is stored in the frame memory 5 and stored in the ROM 2.
Based on the image processing program stored in, the operation processor 4 performs high-speed operation and performs compression processing. The compression process performs frequency conversion and quantization on the image data, and converts the numerical value with a high frequency of appearance into a short number of bits and the numerical value with a low frequency of appearance into a long number of bits.
Decrease overall data volume. When the lens of the surveillance camera 6 is obstructed by spraying or adhesion of tape, etc., the image of the object to be monitored is uniformly dark and flat, and the value of each pixel is The variation is small. Therefore, the data amount of the compressed image data is much smaller than the data amount after compression in the normal state. An abnormality of the lens is detected. Further, when the cable of the monitoring camera 6 is disconnected, an all-black image is taken in the apparatus, and when the all-black image is compressed, the data amount of the image is minimized. (The minimum value is a known value.) Therefore, the cable disconnection can be detected when the data amount of the compressed image data is minimized. The abnormality detection described above
This is automatically detected in the process of compressing image data in the arithmetic processor 4. The above-described abnormality detection of the data amount is executed by a threshold value detection unit and a minimum value detection unit (both are constituted by software) stored in the arithmetic processor 4. Is transmitted to the second monitoring device 2 via the communication line 8. When the received image data is normal, the second monitoring device 2 performs a decompression process and displays a still image on the display device 16 via the frame memory 15. When the cable disconnection of the camera 6 is detected, the message is displayed on the display device 16 and an alarm is issued by the alarm device 18 to notify the observer (operator). Since the displayed image is different between the case where the lens is disturbed by spraying or the like and the case where the cable is cut, the difference can be determined based on the image on the display device 16 and the operation sound of the alarm device 18 can be determined. It is easy to identify the cause of the failure by changing it. As described above, according to the method of detecting an abnormality of a surveillance camera in a surveillance device according to the present invention, an image of a surveillance target is uniformly dark and flat due to the obstruction of photographing of the surveillance camera. When the image becomes an image, or when the camera cable is cut and an all-black image is captured, the abnormality is automatically detected and the information is transmitted to the second monitoring device. The supervisor (operator) of the monitoring device can take prompt action.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of a still image transmission type monitoring apparatus according to the present invention. FIG. 2 is a block diagram showing a configuration of a still image transmission type monitoring apparatus according to the related art. [Description of Signs] 1,11 CPU 2,12 ROM 3,13 RAM 4,14 Arithmetic processor 5,15 Frame memory 6 Monitoring camera 7,17 Communication control unit 8 Communication line 16 Display device 18 Alarm device

Continuation of front page    F term (reference) 5C054 EG01 FC03 FE16 FE28 FF06                       GA04 GB01 HA19                 5C087 AA09 AA10 AA19 AA33 AA41                       BB11 BB74 CC02 CC05 CC52                       DD05 EE16 FF01 FF02 GG02                       GG08 GG18 GG19 GG21 GG24                       GG66 GG70

Claims (1)

Claims: 1. A first monitoring device for transmitting a still image of a monitoring target imaged by a monitoring camera as compressed image data, and an image data from the first monitoring device. A second monitoring device configured to receive and expand the received image, restore a still image of the monitoring target object, display the still image on the display device, and monitor the first monitoring image; When it is detected that the data amount of the image data obtained by compressing the still image captured by the monitoring camera in the apparatus is smaller than a preset threshold, or when the data amount of the image data is a known minimum value And a second monitoring device for displaying and alerting that an abnormality has occurred in the photographing by the surveillance camera when it has been detected Method for detecting abnormality monitoring camera in the formula of the monitoring device.