Metro video monitoring networking system case study (1)

The current Metro station video monitoring is generally divided into two levels of monitoring; in the subway station-end request monitor all the site images, in addition to the monitoring center requirements can monitor their subordinates the MTR station.

Taking into account the problems of funding, in the Center side, generally do not ask and see all subway stations of all images; they are monitor taken two ways: one at the same time monitoring the Metro station a few images, another is the request can be both a subway station in all or most of the images. This will require consideration from the MTR station to the monitoring center of video transmission problems.

★ Various subway station to the monitoring center of video transmission in general there are two scenarios.

The first is to use a digital video codec, through E1 channel SDH provides complete video transmission;

The second way is to use fibre, independent composition of urban video surveillance network system complete the transfer.

If the first method, you need to take up a lot of SDH resources, increases communication system pressure.

In the second way, such as over the traditional point-to-point, to take up a lot of fiber resources. With modern communication technology and digital video technology and the rapid development within the field of the monitoring, real-time digital video fiber optic transmission has also been more and more people receive. City Rails system fiber topology General assumes the chain or network structure, recommended, system remote device to simulated image compression, digital and multiplexer high-speed channel complex received through electrical/optical conversion will signal sent to the fibre channel, the composition chain or ring network; in the Central Office for multiplexing, decode, output analog image, the image quality to DVD. We consider the following case, for example, details of how to use VOX-fibre-based digital video transmission platform solution to urban railway video monitoring networking transmission problems.

★ Status and user requirements

A subway station networking monitoring project, a total of 16 Metro station, each metro station 6-channel image upload, a total of 96 road image.

The whole network has set up a monitoring centre, in the monitoring center to set 6 monitors, while watching a 16 point 96 of 6 images.

At the same time another three independent operation, each with 1 monitor to watch any of the 1-channel images.

¡Ï design principles and solutions

This design looks at the whole system's advanced quality, reliability, flexibility, and in line with the principle of long-term planning, design, comprehensive consideration of system scalability, the business development function and system upgrades.

Under existing conditions and requirements, proposed a Visual communication co., Ltd. Beijing frog's optical digital audio and video transmission platform-VOX system.

VOX system remote device to simulated image compression, digital and multiplexer high-speed channel complex received through electrical/optical conversion will signal sent to the fibre channel, composition chain or ring network; in the Central Office for multiplexing, decode, output analog image, the image quality to DVD.

★ VOX system introduction

VOX system using optical fibre as a transport media, built-in optical transmission module, VOX system to abandon the traditional video point-to-point transmission mode, using a carrier-grade optical fiber communication system digital relay technology, signal regeneration, and progressive local signal cross multiplexing, signal may at any point, and very flexible.

By timeslot can implement image of the whole network crossover, use is extremely convenient.

VOX has a modular structure------include chassis, optical transmission plates, business panels (video compression boards, video unpacking boards, data sheets, E1, Ethernet bridge, Ethernet interface board) module.

Each control point according to the needs and quantities select related modules, usually in the monitoring point configuration a VOX, requires a chassis equipment, optical transmission plate piece, business number plate. In the monitoring center needed a VOX chassis, optical transmission plate piece, business number plate.

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