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  • HD-SDI in the subway HD video monitoring system


        Subway video surveillance needs are mainly the following:
        1, For the key places of the subway entrance and the site provides a high-resolution image video information, generally based on the high-definition camera can do 1280 × 960,1920 × 1080,2048 × 1536 or even 2560 × 1920 resolution, HD-SDI, HD is 1920 × 1080 and 1280 × 720 wide angle, crisp and clear high-definition images, are better able to capture all target details, goals legible requirements.
        2, Provide broader video coverage for the subway system, the HD surveillance cameras erected at the subway entrance can replace the original erection of 2 or 3 SD cameras, and even more. Site District, ticket windows, and out of the bayonet, the main entrance and lobby, simply deploy a small number of high-definition cameras to achieve the desired effect.
        3, In addition to IP network cameras, HD-SDI HD 720P and 1080i/1080P can support 60 frames / sec, double image fluency than marked lofty. You can support large screen display, 16:9 widescreen display, greatly enhance the viewing experience of the operator on the subway supervisory.
        4, HD-SDI HD monitor can provide more real, more details, clear video and create favorable conditions for future intelligent monitoring.
        HD-SDI HD front end application program
        Metro monitoring system in the past has always been run in a hybrid architecture of network monitoring and analog monitor, network monitoring is divided into two kinds of high-definition and standard-definition way. The subway system is still the matrix system with network storage DVR / NVR-based, LAN bandwidth and backbone bandwidth is generally inadequate, local storage and remote video access to good high-definition image effects, HD-SDI HD camera, first solve the front-end video quality with smooth Secondly, in the case of the existing lines are coaxial cable, replacement HD-SDI monitor cameras easier to simply replace the existing analog cameras.
        In order to effectively propose HD-SDI monitor camera in the the subway monitoring system application solutions, I use the subway each monitoring point to make a specific analysis of the actual performance of the HD-SDI and HD.
        1, A subway station entrance: the original system part PTZ analog cameras megapixels IP cameras, analog screen resolution the face feature does not recognize. PTZ cameras can not be a covering specific areas prone to screen dead ends; megapixels IP camera video before there is a delay or loss of frame situation caused due to bandwidth issues, the video results are not complete loss of some of the details. HD-SDI Camera, 1080P screen of analog cameras covering entrances range size is about 2 to 2.5 times, before entering the storage system for real-time image, without delay and dropped frames circumstances.
        2, The subway parking: using analog cameras or PTZ cameras, the picture is not clear enough for vehicles entering and leaving and personnel in and out of existence, the license plate does not recognize, and the lights light hinder monitoring problem, change camera with HD-SDI, and out of personnel recognizable by, license plate to reduce ambiguity, plus HD-SDI camera´s wide dynamic backlight compensation circuit capacity, far better than the original analog systematic solving ability for light impact and backlit wide dynamic, of course, in the parking lot with DVR Master The distance may be a problem, but the mix of transmission media converter, HD-SDI camera transmission distance can be overcome.
        3, Site: Dynamic analysis is an important issue here, in order to master the subway platform layer of crowd dynamics and the edge of the platform crowd activities, and at the same time needed to master the status of the train out of the station, and The Screen Doors functioning or therefore platform layer Camera provisioning density of the strongest and most versatile. The past is no way to simulate the normal state of the high-speed ball to immediately capture subtle movement and a crisp, clear picture, HD-SDI gave an opportunity in the application platform layer. Here HD-SDI camera can not only reduce the the camera laying density, can achieve high-speed ball inspect the site of HD-SDI. As for megapixels IP cameras can provide intelligent analysis, HD-SDI camera ISP chip can also be fixed or high-speed ball machine to provide a complete solution to achieve application.
        4, Ticket vending machines and ticket bayonet: This section of the original subway implement multiple sets of fixed camera monitoring for the ticketing area and even using only a high-speed ball response, so they do not provide ticketing strife verification work occurs at the same time for The bayonet crowds can not clear the record and out of the process, dispute forensics video results error exists. Also changed in this two HD-SDI camera, its compression characteristics without delay, clear record of the votes in the payment of the note-issuing process can be ticketing, and out of the crowd in the ticketing bayonet clear images recorded for reference. View from the subway four key locations HD-SDI camera solutions, the Metro front-end HD acquisition, the network million pixel camera is not the only option, you need to assess how the solution provisioning and Selection. When Tan, the subway HD HD-SDI solutions not just the front-end problems, need to consider the content and method of transmission, storage and management solutions.
        HD-SDI system transmission solutions
        The the metro transmission system using LAN or coaxial cable conversion constitute, remote transmission system is the key to the subway monitoring centralized monitoring and management system for information processing and storage requirements of the local subway system, responsible for a variety of signal and instruction Upload issued, centralized management of the system, the multi-level networking, information sharing, interoperability, mutual control. Remote centralized monitoring and management system, the existing subway is the LAN-based data transfer is done via the Internet, the front-end HD-SDI video and audio digital signal into the DVR / NVR storage end, the audio and video signal conversion after transfer to the OCC centralized compression coding monitoring center control end end control at all levels of the station´s vice monitoring center, issued by the the returns control signal monitoring front-end to complete the two-way video control needs.
        The video signal front-to-storage DVR or NVR, go down to the the Metro OCC transmission network transmission network bandwidth constraints. The HD 720P Specifications stream about the D1 2 times the bandwidth of about 4M, take 1080P calculate the stream with a bandwidth of about 10M. 100M Ethernet, for example, to ensure smooth, in fact at the same time be able to carry about 5-way high-definition image, if the same video source with multiple users to access the bandwidth will be greater. Replaced by Gigabit Ethernet can take on dozens of road can be an effective solution to HD monitoring system for small-scale, for large projects, due to the rapid development of optical fiber communication technology, so that the monitoring system of the optical fiber transmission cost significantly reduce, fiber and Optical the subway monitoring system will become more and more popular.
        Addition, the HD-SDI signal transmission in the subway surveillance system, the short-range 100-200 meters coaxial cable transmission, you can also add a repeater to extend the transmission distance to about 400-500 meters. Subway tunnel in long-distance transmission, can turn Fiber Optical converted to fiber-optic cable transmission, multi-channel WDM / DWDM / CWDM optical wavelength divider in order to meet the one-way or two-way transmission of multi-channel HD-SDI signals, Optical HD-SDI fiber transmission, reached all the way over signal carrier transmission requirements, which allows the HD-SDI camera signal transmission reach 30-70 km. The application of such transmission, based on the existing fiber optic network of the subway system, supplemented by other Internet maximize cost savings and reduce the impact of bandwidth for high-definition transmission.