Wireless network video surveillance application

Since 1997, wireless network products have taken root in the world and began to develop rapidly. Wireless network applications have begun its first spring. With the upsurge of network construction around the world, wireless networks, as an effective supplement and extension of wired networks, rely on their inherent characteristics to play a role that wired networks cannot replace in network applications. Wireless networks eventually gain a place for themselves. However, after the network construction boom has receded, wireless networks seem to have lost some of their development. However, it did not stop and still played a major role in the wirelessization of individuals and businesses and the informationization of rural cities.

The video surveillance market began to flourish in the Chinese market in 2004. From the initial analog monitoring to the digital surveillance of the DVR architecture, until 2007, the network video surveillance system began to show signs of video surveillance. And intelligent trend development. And this trend is irreversible. In the current network platform for video surveillance, wired networks and wireless networks rely on each other's application features to complement each other and go hand in hand. In reality video surveillance applications, due to the different stages of development, cable networks still dominate, and emerging wireless networks are showing strong growth momentum.

At this time, with the rapid development of video surveillance, a simple wired network can no longer fully meet the demand, nor is it the most economical way. Therefore, wireless network monitoring is gradually favored by integrators as a special use mode of wireless networks. More and more monitoring systems adopt wireless methods to establish connections between monitored points and monitoring centers.

1. Advantages of Wireless Network Video Surveillance Compared to traditional surveillance solutions, wireless network monitoring has the following advantages.

(1) Ease of installation In the network construction, the longest construction period and the greatest impact on the surrounding environment is the network cabling construction project. In the process of cable network construction, it is often necessary to break the wall and dig the ground, threading and driving. The biggest advantage of WLAN is that it eliminates or reduces the workload of network cabling. Generally, as long as one or more access point (AP) devices are installed, a local area network covering the entire building or area can be established.

(2) Flexible networking In a wired network, the placement of network devices is limited by the location of network information points. After the wireless LAN is built, it can access the network at any location within the coverage area of ​​the wireless network.

(3) Low maintenance costs The lack of flexibility in wired networks requires network planners to consider the future development requirements as much as possible, which often leads to presetting a large number of information points with low utilization rates. Once the development of the network exceeds the design and planning, it will take more costs to renovate the network, and the WLAN can avoid or reduce the occurrence of such situations.

2. Scope of Wireless Network Video Surveillance Applications WLAN video surveillance can be widely used in a wide range of distributed security monitoring, traffic monitoring, industrial monitoring, home monitoring and other fields, in general:

(1) Wireless network monitoring at ATMs, bank tellers, supermarkets, and factories;

(2) Providing remote wireless monitoring services in nursing homes, kindergartens, schools, etc.;

(3) Unattended systems for power stations and mobile base stations;

(4) Wireless monitoring systems such as oil, drilling, and exploration;

(5) Intelligent building, intelligent community wireless management system;

(6) Pipeline monitoring, warehouse wireless supervision;

3. Outdoor Networking Modes Wireless LANs mainly have the following types of structures outdoors: point-to-point, point-to-multipoint, and hybrid.

(1) Point-to-point type The point-to-point type is often used between two locations of a fixed network to be networked, and is a common way of wireless networking. The network constructed by this kind of networking method has the advantages of long transmission distance, high transmission rate, and less influence from the external environment. Its model is shown in Figure 1.

(2) Point-to-multipoint type The point-to-multipoint type is often used when there is one center point or multiple remote points. Its greatest advantage is low network cost and easy maintenance. Secondly, because the center uses an omni-directional antenna, device debugging is relatively easy. The disadvantage of this network is also due to the use of omni-directional antennas. The omnidirectional propagation of the beam results in significant power attenuation and low network transmission rates. For far-distance far-end points, the reliability of the network cannot be guaranteed.

(3) Mixed type This type is suitable for points in the constructed network that have long-distance points, short-distance points, and points blocked by buildings or mountains. In the formation of such a network, the above-mentioned several types of network methods are comprehensively used. For a long-distance point, a point-to-point method is used, and a plurality of points at a short distance use a point-to-multipoint method, and a blocked point adopts a relay method.

4. The “Wireless Network Video Surveillance System” project of the project is based on unified planning and unified management. It adopts a fixed-site camera and uses a variety of video capture devices (network gun cameras, digital network dome cameras, network video servers, Infrared night-vision cameras, etc.) perform high-quality image captures of important scenes and major parts of the community in different geographical locations and different angles of traffic environment, mountain environment, and high-rise environment, and pass the captured images through radio waves. The transmission method is transmitted to the monitoring center.