The Video Monitoring System Based On Wireless Mesh Network Design And Implementation

This thesis proposes a new wireless video surveillance system implementation,using Wireless Mesh Networks(WMN) as the data bearer network, using VLC videoserver to build the video transmission and preservation solution, using SD card to savethe historical surveillance video and building an FTP server for the client to get accessto these videos. The design combines the structural flexibility, strong coverage,multi-hop short-distance high-speed transmission capability of the wireless meshnetwork with the excellent video streaming technology, video codec processingcapabilities of the VLC video server together. This should greatly enhance theextensibility and scalability of the video surveillance system.In implementation, this thesis builds the main hardware structure of the videosurveillance node with the S3C2440embedded development board of FriendlyARMand EmbedSky companies, selects Deasy company’s USB camera as video capturedevice and Atheros’s802.11G USB wireless network card for wireless communications,and Kingston’s SD card to store the historical videos. The system builds the WMN withOlsrd, and sets up a number of gateway nodes to enhance network throughput, avoidingthe single gateway network transmission bottleneck. And the system uses the VLCvideo server to control the video capture devices and to provide RTP video streamingand local video saving solution. Besides, it establishes an FTP server with Vsftpdsoftware under Linux for users to get the historical videos. The monitoring client nodeis deployed on PC with Windows operating system, and a monitoring interface systembuilt with Qt is deployed on the node for user-system interaction. The monitoringinterface system uses Libvlc library of VideoLAN project to develop VLC playbackcontrols to receive and play the video. In order to combine WMN composed by videocapture nodes with the wired local area network where the monitoring client node is,gateway nodes are used. The monitoring interface system finally provides Quad-dividedscreen polling video play, fixed-point play, automatic and manual page change as wellas historical videos FTP accessing. In addition, the thesis does some extensions for thevideo surveillance system. It adds a kind of video capture node with wireless communication capabilities, the nodes can detect the network status automatically, andswitch to the wireless network by starting wireless networking card with the wirelessrouting protocol when the wired link breaks, and equally switch back to the wirednetwork as the wired link recovers.Compared with traditional video surveillance systems, the system designed in thisthesis has some advantages. Firstly, a wider range of application fields, because it issuitable for both wired and wireless application environment. Secondly, betterscalability, that is to say you can easily add new features on the basis of the VLC videoserver. And last, the design of wired video capture nodes with network switchingfunction can greatly improve the robustness of the cable monitoring, and it is also a newidea for functionality expansion based on networks convergence.