Wireless video surveillance technology is used in many security areas. The subway security system is an important equipment to ensure the smooth organization of the subway and the safety of transportation. The wireless video surveillance system is used in the subway video surveillance system.
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demand analysis
For the subway, monitoring must first meet the needs of safe operation and anti-terrorism. Due to the large passenger flow and complicated personnel, the subway system is an underground space, which is closed, opaque and unfavorable. Once an accident occurs, such as a fire or an explosion, the impact will be very large. Therefore, the suspected explosives must be intercepted in advance, including Some liquids, solid explosives, and poisonous gases are used for comprehensive prevention. In order to prevent passengers from carrying inflammable and explosive materials and other suspicious items that may cause major public safety accidents, the station has also strengthened security measures. However, the existing security equipment only checks the objects and people, and is not safe. Hidden dangers still exist, so monitoring the situation in the subway car has always been a function that everyone hopes to achieve, but the bandwidth limitation and speed limit of wireless transmission have not been well realized, with the issuance of 3G licenses and 3G networks in China. Construction, real-time video surveillance in high-speed subway cars becomes feasible. As the domestic 3G market leader, ZTE has launched the “Network Video†video surveillance system metro wireless solution in line with the needs of the market. It adopts networked and intelligent video surveillance technology to realize the full coverage of video surveillance in the subway. Application, share some experience with everyone here.
Design of wireless fixed network convergence video surveillance scheme
system structure
The "Network Video" video surveillance system uses all-IP technology to provide an end-to-end integrated solution that integrates mobile networks with fixed networks. It provides monitoring front-ends for various wireless networks such as WiFi/2.5G/2.75G/3G/WiMAX. And a full range of versatile wired monitoring front-ends, system management platforms and portals, media sub-forwarding and storage platforms, and a variety of monitoring clients (including mobile client/PC client/WEB client/hardware decoder) Software and hardware devices.
The system is based on the excellent fixed-line + mobile network design concept. According to the carrier-class reliability requirements, it adopts software modular design and advanced intelligent transcoding gateway design to provide high-performance mobile and fixed-line video surveillance. Comprehensive application. For the subway system monitoring, its networking structure is shown in Figure 1.
Front end design
In the subway car, according to the situation of the wireless network, configure the dedicated car 3G wireless video server + dome camera of the corresponding interface, the wireless video server itself can be configured with a hard disk to achieve high-definition, real-time video (D1 format) local storage, according to 3G Network transmission speed, set CIF real-time or D1 non-real-time (down-frame) video uploading platform for the monitoring center and related management personnel to call, in the event of an unexpected event, you can directly retrieve the local video recording stored in D1 format.
For the monitoring points set at each station platform and each entrance and exit, building (support) ladder channel, etc., you can directly use network cameras, such as network high-speed ball, network gun machine, etc., to reduce the construction difficulty, you can also use simulation Camera + video encoder construction.
Access network design
For in-vehicle monitoring points, it is recommended to use 3G wireless networks, such as Telecom's CDMA EV-DO or China Mobile's TD-SCDMA HSPA+ and other latest 3G or 3.5G wireless network technologies to ensure sufficient upstream bandwidth and upgrade to LTE in the future. The internet. For fixed monitoring points in the station, it is recommended to access the network in a wired manner to ensure the stability and reliability of the access.
Monitoring center design
The subway monitoring system monitoring center generally includes three types, which can be divided into three levels from the management. The first type is the station monitoring center, the number is large, and each station has a local monitoring center to realize the browsing of the monitoring image of the station. The control of the camera of this station has the highest authority; the second type of monitoring center is the line subway dispatching management center. Generally, there is one line per line. It is necessary to know the general situation of each station and the detailed information of train operation at any time. The video can be selectively viewed, but the control right of the camera is lower than the station; the third type is the vehicle maintenance center, generally there are 1-2 maintenance centers on one line, and the target audience for monitoring is mainly the station and The various hardware and equipment of the subway train have control rights for certain cameras and the lowest control authority. The networking structure of the line monitoring management center and the station monitoring center is shown in Figure 2.
Mass storage design
In order to save a large amount of video recording data, it is necessary to establish a mass mass storage device. According to the characteristics of video surveillance video recording, IP-SAN storage technology is recommended. Because IP-SAN has the following advantages over other storage methods:
·High cost performance;
· Strong ability to expand;
· Centralized management;
· Ethernet technology is quite mature, reducing the complexity of configuration, maintenance, and management;
· Network-based storage system, data migration and remote mirroring are easy. As long as the network bandwidth is supported, there is basically no distance limitation, which can better support remote disaster recovery.
· Easy to integrate with existing monitoring Ethernet networks;
· The network has no distance restrictions and is easy to deploy.
IP-SAN combines the speed and low cost of SCSI with the ubiquity and ubiquity of IP networks and Ethernet, making IP-SAN storage solutions a cost-effective, scalable and well-known solution.
In the project, it is recommended to use a dual controller magnetic array. One main cabinet can be extended to connect three slave cabinets and provide 51 hard disk slots. Multiple IP-SAN magnetic arrays can be configured for large-capacity storage.
System platform design
The monitoring system platform is divided into two parts: the business management platform and the media service platform, and completes platform management functions such as device and user overhead management, AAA management, service management, device configuration management, platform networking management, operation and maintenance, and remote upgrade of the entire system. As well as video storage and sub-forwarding functions, it provides full network support for business use.
In order to ensure the security of the system structure, the management center CMS+ distributed video monitoring VSS media node construction system is adopted. The CMS equipment is placed in the metro monitoring center, and each station can be set as a VSS media node, or it can be adjacent. The cameras of the two stations are grouped together to build a VSS media node to reduce the bandwidth usage of the video in the entire transmission network of the subway, and at the same time improve the security of the system.
Intelligent application design
The multiplication of monitoring points brings more video information. Massive video messaging means higher bandwidth resources, more storage space and more people to analyze, judge and process video information.
At present, the traditional monitoring system is to observe the monitoring screen by the staff on duty 24 hours, based on the judgment of the content of the video information, analyze and deal with the abnormal behavior, and ensure the basic security of the community through the close combination of civil air defense and technical defense. However, it turns out that after 20 minutes of watching the screen, the human eye will be seriously degraded, and in the face of a large number of monitoring pictures, the possibility of finding an abnormal behavior is relatively small. Based on the physiological characteristics of human beings, it was originally expected to increase the security level by increasing the number of electronic eyes, but now it is unable to achieve the desired intended purpose because of the rapid increase of video information. For the security department, the video surveillance image is an important clue source in the process of detecting major cases. For video recording information that may have clues, it is often dozens of images for ten consecutive days of viewing, traditional one frame playback comparison The way has greatly increased the difficulty of forensic personnel in collecting evidence and the period of solving crimes.
The intelligent video analysis system can solve the above problems well. The system adopts international advanced image processing, pattern recognition and computer vision technology to warn and alarm the abnormal behavior in the video surveillance scene, thus constructing a fully automatic, An intelligent system that monitors all-weather, real-time. The intelligent video analysis system transforms the traditional passive monitoring mode, which is staffed, into an active management and convenient post-search analysis mode. Through real-time video, it automatically discovers suspicious situations and intelligently analyzes alarm devices in the first time. Management system. At the same time, the intelligent analysis system server can flexibly access all relevant front-end devices in a specified area of ​​the IP broadband network, without special upgrades and complicated settings, and the access capability can fully meet the current requirements.
Intelligent video analysis technology is often arranged in two ways. One is to use embedded architecture. By embedding intelligent video analysis software into a video server, network camera and other coding devices with DSP processing chips, local computing and analysis are mainly performed. The picture used is in CIF format. The biggest advantage of this method is that the calculation uses distributed processing and reduces the number of analysis servers. The big disadvantage is that the deployment is not flexible enough, and it is not convenient to adjust after the device is installed. The second method is to use the background processing method to obtain the digitized code stream from the network video monitoring platform through the integration with the monitoring platform, and directly analyze after decoding. All the analysis is concentrated in the monitoring center computer room, and can be configured according to requirements. Adjusting and modifying the front-end camera to be analyzed has nothing to do with the position of the camera. This is its biggest advantage. It can fully save and utilize resources, and can be expanded as needed without having to configure it in one place. The biggest drawback is the increase in the number of analytics servers and the potential for some network traffic to increase. In this system, the streaming media server is used for media distribution and transfer, and the background processing method does not add additional network traffic. Therefore, it is recommended to use the background processing method to construct an intelligent video analysis system application.
In addition, the system also provides intelligent analysis functions including item legacy alarm, area intrusion alarm, face recognition control, abnormal behavior analysis alarm, human traffic statistics and analysis alarm.
Introduction to system advantages
The system subway solution provides a flexible mobile access method, which achieves seamless coverage of video surveillance, and the system also has the following features.
IPTV high-capacity system basic technology, distributed networking architecture, modular design
· Adopt IPTV large-capacity sub-forwarding technology architecture to achieve user capacity of more than 1 million systems;
· Distributed networking architecture, using system management center + node mode;
Modular design, the whole system includes central management system CMS, media distribution network VDN, media scheduling unit, streaming media server SS, dedicated interface machine, etc., all of which can be deployed independently;
· Adopt dual-system hot backup or load balancing to achieve functional module level security.
Decentralized domain and refined authority management
·Flexibly support the user's hierarchical management function of the industry customers, which can realize the self-management of the group customers, realize the overall operation of the monitoring service, and divide the storage and forwarding resources for different users;
· Video browsing permissions: including real-time video playback;
· Configuration management rights: including configuring the video parameters of the front-end device, setting the alarm switch, alarm parameters, and alarm linkage configuration.
· Recording plan configuration permission: including setting monitoring point timing recording plan;
· Video browsing permission: including video file query, video and video playback;
·Cloud mirror control authority: including cloud mirror control operation, a total of 9 levels;
· Alarm management authority: including alarm information reception and alarm information processing;
· Language communication authority: including language intercom, voice broadcast, etc.;
· User management rights: including management operator account configuration, etc.;
· Device management authority: including management of PU devices and channels;
· Video wall management authority: including the configuration and use of the video wall;
· Electronic map access rights: including the configuration and use of electronic maps.
Unified network management and operation, unified management of network equipment
· The system uses the SNMP+TR069 protocol to build a unified network management system;
· The master device such as the platform server and the core switch adopts the SNMP protocol for network management;
· The large-volume and frequently changing video encoding device PU and client CU adopt the TR069 protocol for network management, which is easy to operate and can be incorporated into the ITMS unified network management platform;
· Unified user account authentication: The user's mobile phone number can be used as a unified account for the user to use the system.
High security
· The client provides USB Key security authentication function, MAC address and IP address or address segment binding function, simultaneous login account limit, user password and account expiration settings, and password change prompts to ensure the security of the client. ;
· The platform server adopts the Linux operating system, configures the hardware firewall and virus-killing software, and adopts port blocking and access restrictions to ensure the security of the platform.
· Adopt streaming media encapsulation technology to ensure media transmission and storage security through MD5 signaling encryption, media fragmentation storage, and dedicated transcoding tools;
Supporting the mutual backup between POP units in the service node and the mutual backup between the service nodes, and ensuring high reliability of the system from the application layer.
Fixed network, mobile monitoring and fusion support, intelligent transcoding
· The system supports both fixed network and mobile monitoring services, and provides a full range of mobile monitoring module components such as MSP, PSS, VAU, wireless PU, M_CU, etc., and can build a complete integrated video surveillance service solution without the participation of other manufacturers. ;
· The system can adapt to various network environments, including: wired network (xDSL, LAN, xPON, E1), etc.; wireless network (CDMA1X, EV-DO, WCDMA, EDGE, TD-SCDMA, HSD/UPA, WiMAX, WiFi), etc. ;
· The system can be integrated into the fixed network front end, mobile front end, fixed network / mobile dual mode front end, and supports multi-stream PU equipment;
· The system supports fixed network and mobile phone monitoring client access services;
· For 3G mobile network applications, the system can provide intelligent transcoding function, and automatically select the optimal transcoding scheme through intelligent transcoding mechanism to output media stream suitable for mobile phone playback.
Cloud mirror lock function
· Support users to lock the PTZ. Other users cannot operate the PTZ during the user's lock on the PTZ. Only the current user can control and unlock the cloud mirror.
· After the cloud mirror is locked, the client gives a corresponding prompt when other users perform operations, such as "the cloud mirror has been locked by the user XXXX, and the operation is not allowed";
· Enterprise initialization administrator can force unlocking;
· Allow the user to perform a lock operation on the channel only if the account has the cloud mirror lock permission and the cloud mirror control permission of the corresponding channel has been assigned;
· MOC client, WMPortal, MOCPlayer provide this feature.
Provide professional network quality analysis tools
· The system maintenance management portal supports the external IP address and intranet IP address of the PU, which helps the operator to manage and maintain the service.
· Integrated professional network quality detection and analysis functions in the client. When the client plays a flower screen, a green screen, a card, etc., the network abnormal state can be visually displayed in the client, which helps the user to locate and solve the fault by himself;
· Support the display of network status in the status bar of the MOC client, including information such as total code rate, packet loss rate, and jitter;
· Supports diagnosis of network conditions. It can count the following data (number of lost packets, packet loss rate, code rate, number of out-of-order packets, frame size, network jitter, etc.) and graphically display the network status.
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