| Traditional security monitoring systems use wire transmission in most cases and wire transmission need wiring along the way,we have to face the high cost in long-distance monitoring;it’s unable to complete the wiring of all the cable line in the complex environment of the forest fire prevention. The transmission rate of second-generation communication system is50kbps or less, while the video need transmission rate in500kbps or more, there are many other wireless transmission technologies such as Bluetooth, WLAN, etc. have a high transmission rate, but the within100meters transmission distance can’t meet the requirements for long-distance wireless video transmission.With the development of embedded technology and3G technology’s maturing, the video surveillance gradually out of time and space’s constraints to achieve a long-distance and real-time video transmission.people use such a network video system can be achieve monitoring don’t have to arrive the forest, this has very important significance for forest fire prevention.The monitoring terminal designed include the core board whose processor is TI’s OMAP3530,3G module, GPS module and CCD camera, core board connect3G module by USB,GPS module is joined together with core board by serial connection. The thesis discussed in more detail overall system development process.First,the dissertation completes hardward and software platform’s building,then discusses video capture process in monitor terminal,realizes V4L-based video under the Linux system and then use the H.264video compression technology to compress encoding, at the last video is used the RTP protocol for3G transmission.In order to achieve the collection of video information, the thesis complete the TVP5146’s initialization, the kernel configuration which is related to this thesis, GPS module drivers transplantation;we use multi-threading technology and H.264video compression technology to achieve efficient processing of the video; In order to achieve the video’s real-time transmission, the thesis complete of3G card,the transplantation of embedded database such as PHP,Apache,SQLITE,JRTPLIB,etc.and PPTP VPN client’s establish;the paper complete the decoder controls’s production of H.264and the browser’s load to achieve the playback of video.The emphasis and difficuity of this article focuses on the implementation of3G transmission, as we all know3G devices Internet IP address is random, In order to achieve the monitoring center control terminal equipment,equipment use server access gateway assigned to the virtual proprietary network (VPN) in order to establish a control terminal and virtual private network monitoring centerr, so3G devices and IP-one correspondence.By experimental validation, the system can be realize25per second speed transmission of video images, the design is feasible, the system has high stability, scalability and practical value. |
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