Impact of weather on frequency monitoring system setup

As the main component of the security system—in the process of setting up the railway video surveillance system, due to the different geographical environment and application characteristics, there are still many restrictive factors in the construction of high-speed railway video surveillance systems. For example, video surveillance sites are usually scattered, The span is relatively large, usually a few hundred kilometers or even thousands of kilometers; video surveillance cameras work outdoors, the environment is usually rather harsh; video capture equipment, codec and some storage devices are distributed in the unmanned room, with high installation and debugging costs; Complex analysis of the environment, frost, rain, fog, camera shake, lighting and other interference factors may lead to false alarms. Therefore, the security system is not a "security" slogan.

The uncertainties of natural phenomena such as wind, thunder and lightning, etc. It should be said that the outdoor environment is a great test for the camera. Rain, snow, high temperature, low temperature, lightning, strong wind, etc. may all cause the camera to malfunction. Each damage link may cause system maintenance. The rapid increase in cost, while the railway project is often characterized by a large span, is often far from high mountains, and sometimes even high-altitude operations, and once the system is open to operate and then apply for operations will encounter many restrictions, resulting in increased costs. Therefore, the selection, installation, and wiring of the outdoor camera and the high quality of the camera itself are particularly important.

Long-distance camera problem High-speed rail monitoring, according to the point is mainly divided into indoor room, indoor waiting room, ticket office and outdoor plaza, platform, etc., these locations of the camera deployment is not particularly special place, but another point of more applications is Along the railway line, the long-distance camera is the absolute use of long-distance cameras. Long-distance cameras may need to monitor tens of meters, hundreds of meters, or even several kilometers. This means that long-range cameras may require a few kilometers of observation. In this way, the camera is not a simple camera with a longer focal length lens. When the focal length is pulled to a certain length, it is very difficult for the manual keyboard to navigate to a very distant target. That is, the microstep control function of the camera. Very important. In addition, high-altitude camera anti-jitter, night vision lighting issues need to be considered.

In the pre-precision high-speed rail monitoring, in order to quickly locate the scene or respond to the alarm, usually the client will set a plurality of preset positions for quick application calls in the future. The number of preset positions is usually not a problem. Most cameras currently support 128 or even 256 presets. Bits, but not much used in actual projects, but the accuracy of the preset position is an important indicator to examine the PTZ camera, for example, when the user set a preset position, usually after a call, some camera presets There will be an offset, so that you have to manually fine-tune again, lose the significance of the preset position itself, affect the use.

Encoder and DVR selection High-speed railway projects, encoders and DVRs are usually deployed in various site computer rooms. Therefore, encoders and DVRs need to have ultra-stable performance (embedded encoders and embedded DVRs are preferred). Networking capabilities, remote management and upgrade capabilities. Because the network system has a complex architecture, a large span, and many routes, the encoder device needs to have a local cache function. In the case of temporary network terminals, the video will not be lost. Once the network is restored, the video can be supplemented to the NVR storage.

In addition, image clarity, dual stream support, two-way audio support, and the number of alarm inputs and outputs are all indicators that need to be considered.

Most unattended sites are stationed in order to reduce the number of stations. Many stations in the high-speed rail area are unattended. In addition, the railway will have an electric power room and a communication room every several hundred meters. These rooms are basically required to be unattended and use video surveillance and alarm systems to detect whether there is any intrusion and whether there is any change in the scene. Therefore, the demand for video surveillance in the unattended high-speed train room is very high.

Although the "Technical Code for Railway Integrated Video Surveillance System" has definite technical specifications for railway surveillance equipment, including front-end cameras, pan/tilt heads, video encoders, and storage devices, outdoor cameras should have strong light suppression and backlight compensation; Color gun camera resolution indoor not less than 480TVL, outdoor not less than 540TVL; day / night conversion camera resolution. However, whether the high-speed rail monitoring system can play its expected role is another matter. This reminds me of the recent theft of the Forbidden City. When we put too high expectations on security monitoring equipment, we can really do so. What? When the speed of the railway far exceeds a thousand miles, who will pay for our security?

Coding Standards Currently, the MPEG-4 coding technology and H are mainly used in railway projects. The 264 encoding technology may deploy AVS encoding in the future, and the intra-frame compression and the inter-frame compression may be used to remove the redundant information in the time and space of the video information. The delay of coding equipment shall not be greater than 300ms, the delay of each level of forwarding shall not be greater than 500ms, the delay of decoding equipment shall not be greater than 300ms, and the PTZ response delay shall not be greater than 500ms. The delay of the system front-end acquisition equipment to the user monitoring terminal shall not be More than 3s.

The explosion of demand for intelligent video analytics The function and application requirements of intelligent video analysis technology have been clearly written in the "Technical Code for Integrated Railway Video Surveillance System". It is precisely because of the express provisions that almost all high-speed railways in China will use video analysis technology. With the smart video analysis technology being written into the standard, the application of intelligent video analysis technology in the future will be more and more. Currently, hundreds of high-speed railway lines have deployed hundreds of video analysis channels, mainly for intrusion detection analysis mode, and have achieved good results, but due to the characteristics of the railway system, such as terrain, weather conditions, and multiple interference sources, plus video Analytical technology is currently not mature. From this point of view, high-speed rail video surveillance still faces challenges.