Intelligent Community Video Security Monitoring System

The video security monitoring system is mainly used to collect the important entrances and exits of the community, the video surveillance images of each unit entrance, parking entrances and exits, community perimeters and various public places and other key areas, enabling the on-duty personnel in the community to monitor the entire community in real time. On-site situation; and able to control each video image, real-time record, playback retrieval video files, management center can achieve remote monitoring and control through the network.

The video security monitoring system collects the scene through the low-illumination color camera, and the image signal is transmitted to the hard disk recorder of the security center via the video transmission cable. The system has multiple functions, completely

The video security monitoring system generally consists of four main parts: front-end, transmission, control, and display recording.

2. The basic composition of the system

2.1 front-end equipment

The front-end device is a camera device installed at the scene, including various types of cameras, lenses, shields, and supports. Its task is to convert the image signals from the scene into electrical signals, which is the basis of the entire system. Only when good image signals are captured at the front end can high quality echo and storage be possible at the back end. The image quality of the front-end equipment must be well-guaranteed. According to relevant standards, the rear-end imaging resolution of the system must not be lower than the TV line.

The camera is divided into a variety of types according to the type of image, the illumination applied, the type of camera device, the range of the applicable spectrum, the environment in which the camera is used, and the use of the camera. When the field device is selected, appropriate consideration should be given to various environmental factors. .

The installation of the camera should fully consider the actual situation on the site and be arranged and installed according to the protection requirements of the object to be protected, ensure the effective monitoring range of the camera, and ensure that there is no surveillance blind spot. Before or after the camera is installed, the camera is adjusted according to different environmental factors and the type of camera. The lens focal length, focus, and aperture of the camera are adjusted correctly. There is also white balance adjustment, video gain, synchronization, and electronic shutter. Adjustment of background light compensation and other items. Make the camera work in the best condition to ensure the best monitoring effect.

Each camera adopts centralized power supply, and each camera draws power from the system power distribution box. The system uses an independent power supply for centralized power supply to ensure the safe operation of the equipment and good synchronization performance of the equipment. The power output from the regulated power supply equipment is uniformly supplied by the system distribution box to the field devices and the central monitoring equipment.

This is our more commonly used Japanese TOTA-300 color camera. Its technical parameters are as follows:

Imaging element: l/3" SONYHADCCD

Pixels: PAL: 500 (H) × 582 (V)

Horizontal Resolution 420TVL

Minimum illumination: 1.0 Lux/F1.2

Signal to noise ratio: ≥48db

Automatic electronic shutter: PAL: 1/50 to 1/100000se

Automatic aperture: Video/Dc servo type optional

Automatic White Balance: Yes

Automatic Gain Control: High/Low Switch

Backlight compensation: 0n/Off switch

Video output: 1.0Vp-p/75Q

Power: DCl2V 10%

Power: 3.5W

System temperature: -20°C—50°C

Dimensions: (mm) 58(W)X 50(H)X 56(L)

2.2 Control section

The control part mainly includes a video switcher, a pan-tilt lens controller, an operation keyboard, various control communication interfaces, a power supply, an accompanying console, a monitor cabinet, and a system host. In the actual monitoring project, we use the networked digital monitoring system host of Japan TOTA. This system replaces the original CCTV monitoring system to prevent the occurrence of unclear picture quality, cumbersome storage, and video tape replacement due to repeated use of video tapes. The digital monitoring system of high-tech independent property rights, such as expensive and other issues.

The system uses hardware compression, real-time acquisition of audio and video signals (P-Zag or NTSC) compressed into a standard MPEG-1 file or MPEG-4 file, and can be realized on multiple hard disk loop recording. At the same time can store multiple channels of audio and video signals, and ensure the synchronization of audio and video. Support network transmission such as LAN, ADSL, DD5, PTSN, support network interconnection, build large digital video matrix.

This system provides the necessary decision-making basis for the operator to judge the seriousness of the situation on the site. The system can implement automatic alarm response according to the set program, such as turning on or off auxiliary equipment.

The host can set the recording speed and video quality of each channel separately, and record automatically during the specified time period. Timed continuous recording and dynamic alarm recording can be realized. With video dynamic alarm function, you can freely set the video alarm arming area. Digital hard disk video recorders provide a variety of module functions in the control software: electronic map module; video alarm module. Suitable for any existing network, scalable multi-level sub-control. Repost

You can also print the snapped image at any time for backup.

Screen split: 1, 4, 9, 16, 24, 24 monitor mode. Search by date, time, and monitoring point. Password protection is used to protect the system settings and prevent unauthorized persons from modifying the system. The monitoring point text information can be superimposed on each video to facilitate monitoring. Friendly human-machine interface is very suitable for modern security management needs.

3. Perimeter alarm

In the monitoring and security system engineering conducted by the author, perimeter alarms are often connected to the monitoring host. It consists of a perimeter detector, a control panel, and a connection to the monitoring host.

Perimeter detectors are special types of detectors. It consists of several types of detectors that can perceive the perimeter being invaded, known as a "fence." Perimeter detectors are classified in many ways, such as hidden and visible, passive and active, space and linear. Perimeter detectors can send alarm signals to the control panel and can also perform on-site alarms.

In order to be able to better guarantee the safety of the community, the installation of perimeter anti-theft anti-theft alarm system is to alert the perimeter of the community. The alarm equipment adopts a four-beam infrared radiation detector installed at the top of the community wall and the gate. The active and infrared detectors are placed reasonably at the transmitter and receiver to prevent the occurrence of surveillance blind spots.

The active infrared fire detector is an optical intrusion detector. Its working principle is to actively transmit and receive infrared energy, and does not generate false alarms or missed alarms due to changes in the environment. One end emits an infrared energy signal, and the other end receives an infrared signal, thereby forming a number of barrier-like transverse barriers. Therefore, the contact area between the active infrared beam and the space is narrow, so that false alarms are minimized.

4. Image compression technology

The image compression is divided into soft compression and hard compression, and they are compared below.

4.1 Soft Compression DVR Cards and Hard Compression Cards

Soft compression card, also known as video capture card, the circuit board card is mainly composed of one or more video capture chip and peripheral components, circuits, circuit structure is simpler than the hard compression, the cost is much lower than the hard compression. This card is only responsible for capturing video, and video compression, decompression, and other video processing are implemented by cPL operations.

Hard compression card, also known as video capture compression card, the difference between the circuit board card and the soft compression card is that the video compression and decompression part of the circuit structure, the video compression is not given to the computer cPL to handle, but to pay a DSP chip To deal with. So the hard compression card circuit is more complicated.

4.2 Comparison of soft compression DVR cards and hard compression cards

4.2.1 Service life

DVR product replacement is fast, the fastest change is the compression algorithm and software features, soft compression card (here refers to the genuine soft compression card) flexibility, it does not partially soften the software and compression algorithm in the chip, upgrade flexibility , It is not easy to be eliminated, and hard compression DVR is to write the compression algorithm to the DSP chip, upgrading trouble, and the service life is short. As we all know, MPEG-1 hard compression cards worth a few thousand or even more than 10,000 yuan in previous years have been eliminated in less than a year because they cannot be upgraded.

4.2.2 Compression efficiency

In terms of video compression capabilities, hard compression is better than soft compression. Since the soft compression card uses CPU compression and consumes computer resources, rational configuration of the computer is the key to the long-term stable operation of the soft compression DVR. With the speeding up of mainstream CPU performance and speed, the soft compression processing capability has also been strengthened. Using ordinary Celeron 1.7G can compress 4-8 (352X 288) real-time, once the near future 64-bit Windo's operating system On the market, the soft compression card adopts the cheap .~MD64 bit CPU to compress the video, it becomes an easy matter, and compressing 32 channels in real time will no longer be a problem. At this point soft compression will probably replace hard compression cards.

In terms of compression ratio, the newly introduced soft compression DVR cards mostly use MPEG-4 or H.264 algorithms, each of which accounts for 30-hours per hour.

4.2.3 Image Quality

In terms of image quality, video capture chips, circuit noise immunity, resolution and compression algorithms are mainly decided, and compression algorithms and compression ratios determine the quality of playback DVR video.

5. Conclusion

The smart community is in the ascendant and its future is bright. The security system is an important part of the smart community. The perfection of the system has also become an important basis for measuring the smart community environment. The author believes that the smart communities can choose the composition of the security system according to their size, comprehensively consider the advanced nature and reliability of the technology and economic feasibility, and choose the solution that suits them.