Research and Design of Highway Video Network Monitoring Platform

Abstract: This paper analyzes the urgent need for the network sharing of traffic video surveillance resources in the current construction and operation of the existing highway video surveillance system. Under the concept of traffic monitoring domain, the resources in the domain are uniformly named and authorized, and the resources inside and outside the city are formulated. Access and control rules, and on this basis, integrate the public video resources of the traffic leading city, and build a multi-level traffic video networking monitoring platform within the province, so that relevant operational management departments in the province can share traffic video resources for road operations. And management decisions provide reliable basis and guarantee, and provide good business support for traffic emergency command and rescue systems.
Keywords: traffic information engineering; video network monitoring; traffic monitoring domain; video resource integration

0 Introduction With the advancement of highway construction in the country, the proportion and complexity of video surveillance systems in the entire monitoring system is increasing. Because in the early days of highway construction, there are basically no provincial highway video resource network monitoring programs in all provinces. Planning, the video surveillance program, technical indicators, equipment models and interface standards adopted by the completed highways have different degrees of difference. With the gradual formation of the high-speed road network, the video surveillance systems independent of each other on the expressways have gradually failed to meet the management needs, and the provincial-level management departments cannot have a comprehensive grasp of the traffic operation status of the entire operational road network. Non-rich video surveillance resources cannot be shared between the various functional management departments of the province, and even duplicate construction in the same key monitoring area occurs. The urgent need for video surveillance resource sharing is driving the provinces to vigorously promote the construction of video resource network monitoring systems. How to use the international standard video codec protocol and open network streaming media access protocol to integrate and enhance existing monitoring resources. It makes the video surveillance system and other subsystems seamlessly connect and realize management and control on a unified operating platform, realizes the network sharing of provincial video resources and provides strong support for traffic emergency command. The urgent task of network operation management.

1 System Networking Model The provincial highway traffic monitoring network has a complex structure, which is not conducive to the integration of the entire monitoring network planning and system resources, and is not conducive to the realization of the province's video network monitoring mechanism. Through the analysis of traffic management level and road network construction and operation status, combined with the principle of “land management” of transportation facilities and equipment, the concept of “traffic monitoring domain” is abstracted on the existing highway video surveillance system, and provincial traffic video is Monitor the networked monitoring platform for unified modular design, simplify the corresponding control and data flow, and integrate the video surveillance resources across the province in the most compact and modular way. The so-called traffic monitoring domain refers to the collection of road infrastructure that is “in a certain geographical area, has a certain amount of traffic monitoring resources, is within the same logical structure of the networked nodes, and can be controlled according to the same networking rules. ".
With the concept of traffic monitoring domain, the monitoring resources and infrastructure in each traffic monitoring domain can be re-integrated according to the requirements of the province's video resource network monitoring rules. By investigating the current construction and planning status of the expressway system, according to the administrative affiliation in the road network operation management, the high-speed road section companies are divided into relatively independent monitoring domains. The monitoring domain consists of a video surveillance resource and a video surveillance management system. The video surveillance management system controls and controls all video surveillance resources in the domain, as shown in Figure 1. Each traffic monitoring domain is an independent autonomous unit that can complete the management and control of video resources in its own domain, and can form a larger traffic monitoring domain by networking with relevant monitoring domains under the requirements of the province's unified video resource network monitoring rules. Thereby, the transportation video network monitoring platform in the province, province and even the whole country can be realized.

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2 Resource unified naming and identification
2.1 Traffic monitoring domain naming Each traffic monitoring domain in the video networking monitoring platform will be given a name, refer to the Domain Name System (DNS) on the Internet, and the resources in the domain are uniformly named according to certain rules. The resource server performs domain name resolution. When a plurality of traffic monitoring domains form a tree structure according to their management functions, the name of the traffic monitoring domain may be represented by a domain name according to its tree structure, and the names of the respective traffic monitoring domains are preceded by a "." connection.
2.2 Naming of monitoring resources The naming of resources in the traffic monitoring domain is based on the name of the resource plus the domain name of the traffic monitoring, and is connected by the "@" symbol. The resource name is recommended to use English letters and Chinese pinyin. The use of this naming method can effectively avoid the problem of resource duplicate names in different domains, and is conducive to the realization of network addressing.
2.3 Digital ID of the monitoring domain According to the affiliation of the monitoring domains at all levels, the monitoring domain and its intra-domain resources are uniformly numbered, and each of the monitoring domains is identified by a more streamlined digital ID to facilitate the exchange of computer information systems. , identification, storage and processing.
The monitoring domains at all levels are identified by a fixed-length digital ID, represented by a 9-digit decimal number, and are composed of a provincial identification code, a monitoring domain identification code, and a resource reservation sequence from high to low.

2.4 Digital ID of the monitoring resource The monitoring resource ID uses the encoding rule of the monitoring domain ID, uses the resource reservation part in the monitoring domain ID, defines the resource type and identification code, and forms a complete resource ID together with the monitoring domain ID. The rules apply to all levels of monitoring domains, users, encoders and cameras.

3 resource access rights
3.1 Definition of Permissions All users and resources in the traffic monitoring domain need to set corresponding permissions to distinguish the user's access level and restrict user access to resources. Permission settings should be as convenient and flexible as possible, and easy to verify and modify. Through the analysis of system functions and user levels, permissions can be divided into four kinds of permissions: viewing, control, modification, and network management. These four permissions are completely independent, corresponding to different operations, as defined in Table 3.

According to the scope of each permission, the advanced, intermediate and low levels are subdivided, as shown in Table 4.
3.2 Assignment of Permissions Users and resources within a monitoring domain can be assigned the appropriate permissions based on the type of management they have and the level of access they have. The newly added users and resources of the system do not have any permissions, and the authorized users need to assign permissions to them to enter the system for access and operation.
The allocation of rights should be completed by users with authorized rights. Each monitoring domain should be set up with a small number of authorized users with authorized rights. The user and resource registration information can be changed at any time, and the system for granting and reclaiming users and resources can be granted. Permissions. For users who do not have authorization rights, even if they are the most advanced viewing or supervising users, they cannot authorize ordinary users.
The four permissions of the platform are completely independent and do not have any cross-implicit relationship. Each user and resource in the domain can have multiple permission categories and levels. These permission levels are independent of each other and do not interfere with each other. When permissions are assigned, one or more of these permissions can be assigned and reclaimed, and modifications to one of the permissions do not affect other permissions. For the general users in the system, they can be granted the right to view, for the higher-level users with resource control needs, they can be granted control rights; for the highest level users can be given their supervisory rights, all granted permissions are only in their The scope of action works internally.
3.3 Authentication of Permissions The verification of permissions is performed by the resource management server in the domain. When users log in to the system and access resources, they need to initiate a permission verification request to the resource management server to obtain permission to access the resource. Only users who have obtained access permission through privilege verification can enter the system to use resources.
Verification of permissions includes access category verification and level verification. When a user requests to use a resource, the resource management server determines which permission category to verify based on the type of operation requested by the user. Then look at the permission level required by the resource and compare it with the user's permission level. If yes, give the user access to the resource. If not, the user is denied access to the resource.
The control right of the resource can only be given to one user. When multiple users need to control one resource at the same time, the user can control the power of the resource according to the level of the user control authority. In an emergency or emergency situation, high-level users can “grab” control of low-level users.

4 Resource cross-level access In the new monitoring network model, all traffic monitoring domains are logically independent and complete. Each monitoring domain is responsible for the management and maintenance of all users and resources in the domain, between the monitoring domain and the adjacent domain. Open a digital video transmission channel, form a tree structure that matches the administrative affiliation, and complete video network sharing with the superior domain and other monitoring domains. The video access inside the monitoring domain can be operated according to the requirements of the original system, directly accessed according to the rights, and the streaming media server where the video resource is located obtains the media stream from the video encoder, and the media is forwarded to the user to call the computer for playback and reproduction. If the accessed video resource is not a resource of the local domain, that is, the user needs to access the cross-domain resource and view the external domain video information, the route search algorithm needs to find the streaming media server of the adjacent domain and issue an access request to the domain. The streaming server of the adjacent domain continues to complete the acquisition of the video stream. In this way, a recursive resource access rule can be designed. The streaming media publishing server accesses and addresses the video monitoring resource by providing a unified resource access algorithm to its neighbor server and local users. The algorithm flow is shown in Figure 2.

Step1: The client sends a “start to view command” to the streaming media publishing server.
Step2: The streaming media publishing server receives the “starting to view command” issued by the calling client through the TCP/IP network.
Step3: Determine whether the streaming media publishing server has connected to the requested video. If there is no connection, go to step 4 to execute, otherwise enter step 11 to execute.
Step4: According to the requested domain name of the video resource, determine whether it is the internal video resource of the domain. If yes, connect the front-end encoder and the camera and enter step 5 to execute. Otherwise, the internal resources of the domain are not entered into step 7.
Step5: Connect the internal video encoder of this domain and prepare to receive the video stream.
Step6: Determine whether the connection encoder is successful or not. If the connection is successful, go to step11 to execute, otherwise the connection fails and enters Step10 for execution.
Step7: Find the foreign domain streaming media publishing server to which the request video belongs through the routing table.
Step8: Connect to the external domain streaming media publishing server and prepare to receive the video stream.
Step9: Determine whether the connection to the external domain streaming media publishing server is successful. If the connection is successful, go to step 11 to execute. Otherwise, the connection fails and enter step 10 for execution.
Step10: The connection failed, fill in the relevant error message.
Step11: Record the command information into the watch list and update the send list to prepare to send the video stream.
Step12: Send a start response command response to the client, and the process ends.
Through the above resource access mode, the user can access the video monitoring resources in the monitoring system across the multi-level streaming media server. This recursive resource access method is simple and effective, and can save bandwidth when multiple upper-level servers access the same monitoring device, which is very important for the transmission of video images.

5 Principles and Requirements of System Networking The traffic video network monitoring platform is built on the basis of the existing video surveillance system. The design and construction time of each section of the expressway is different. The video surveillance adopts different technical standards, and the system reserved interface is not uniform. The unified management of networked monitoring brings difficulties. Combined with the current status of road network construction and operation, the network construction of traffic video network monitoring platform should follow the principle of “maintaining the status quo, providing interfaces, backward compatibility, and policy guidance”. The so-called maintenance of the status quo refers to all the systems on the existing monitoring network, try not to change, protect the original functions and investment; provide the interface to provide the necessary data transmission for the original system that needs to be used. Interface, convenient for data transmission and exchange; backward compatibility refers to the use of mature technologies and solutions of international standards, to facilitate the subsequent system maintenance and transformation; policy guidance refers to the existing monitoring system should propose its networking The guiding opinions of the monitoring, each participating in the networking department, under the guidance of this opinion, will be implemented according to their actual conditions.
The video networking monitoring platform features and system networking requirements are as follows:
(1) Video multi-level network monitoring. The networked monitoring platforms at all levels are self-contained, and can complete all monitoring work within the domain. At the same time, it can form a larger networked monitoring domain with adjacent domains and upper-level domains, and can be located anytime and anywhere through unified domain name identification of resources in the domain. Use intradomain resources.
(2) Uniform identification of resources within the network. Combined with the administrative level of the provincial network monitoring entity and the business affiliation relationship, under the concept of the traffic monitoring domain, the unilateral naming and authorization of the intra-domain resources, including user identification, role identification, organization identification, etc., facilitate user information sharing among various information systems. Exchange and exchange, realize localization of resource management and globalization of resource access, and improve the uniformity and consistency of video resource management within the province.
(3) Uniform access to resources within the network. In the provincial highway video resource networking monitoring platform, the certification management specification for unified naming rules is established, the resource access control rules and authorized access procedures within and outside the domain are established, and a unified identity authentication and management system is constructed to achieve unified portal, unified authentication and unified access. The goal of control.
(4) The user authorizes roaming throughout the network. In multi-level network monitoring, an identity control system based on a combination of users, user groups, services, and roles is used. Authorized users can access any resource in the domain as long as they complete the authorization authentication in their registration domain, without concern for which resource is located. Among the sub-domains; the rights of specific users and cameras can be upgraded or reduced, and even their rights can be reclaimed (in case of emergency); the user rights and resource rights are modified and roamed to notify the entire network and take effect immediately.
(5) Reasonable use of network resources. The shortest path connection is used between media publishing servers located in each subdomain to monitor and evaluate the network connection between each connection in real time, dynamically adjust the number of network connections between each connection, and use multicast within the domain as much as possible. Technology to minimize the duplication of media streams and use valuable network resources between subdomains in an optimized media forwarding manner.
(6) Compatible with multiple encoding formats. The provincial highway video resource network monitoring platform can effectively integrate the relatively scattered and independent road video surveillance resources built in different periods and using different monitoring technologies on the provincial platform, supporting MPEG-4, H. 264 and other video encoding formats, support video codecs from multiple manufacturers, support various matrix control protocols such as KALATEI, AB, AD, etc. The system configuration is flexible and diverse.

6 Conclusion The highway video surveillance resources are very rich and need to be comprehensively managed and utilized. By using the concept of traffic monitoring domain to simplify the large and complex monitoring system networking model in the province, formulate unified networking rules and access procedures, integrate public video resources in the transportation field at a higher level, and improve the networking of traffic operation management departments at all levels. The ability to share video assets. The construction of a multi-level traffic video networking monitoring platform within the provincial scope enables the relevant operational management departments in the province to share traffic video resources and provide good business support for the traffic emergency command and rescue system. It provides reliable guarantee for the unified coordination, command, dispatch, rescue and other operations of the transportation situation in the entire provincial traffic network, improves the operational capacity and service level of the traffic network, and operates and manages the road network. Provide further basis for construction. Through a unified video network monitoring platform in the province, it is also possible to extend the scope of video resource network monitoring to various traffic areas such as inland rivers, oceans, railways, aviation, transportation, etc., so as to achieve provincial, inter-provincial and even nationwide traffic. Video networking monitoring platform.