Design Of Construction Site Wireless Video Surveillance System Based On3G

With the rapid development of economic society, production safety has got great attention of the whole society. People more and more urgent demand to improve the level of production safety. Video surveillance systems are playing an increasingly important role in all aspects of production and everyday life. Because of the complexity of the construction site environment and the mixed and strong mobility of staffs and people, construction site become the place where various accidents occur frequently. Pose a great threat to the life security of workers and the property of enterprises. Video surveillance systems improved the supervision method on construction sites; facilitated the management of the construction sites. The traditional cable monitoring system cannot adapt to the construction site due to the difficulty of erection and high cost. With the fast development of3G communication network in our country, the coverage area of3G network become wider and wider, at the same time, the cost of3G keeps reducing. With the features of high speed, wide coverage area, stable signal, convenient connection, the3G wireless video surveillance systems get fast developed.The construction site wireless video surveillance system based on3G is mainly composes of two parts: the video surveillance front-end component and the surveillance terminal component adopt client/service (C/S) mode.Video surveillance front-end adopts S5PV210Cortex-A8architecture microprocessor as the core of hardware platform. The peripheral hardwares of this system consist of NAND Flash, SDRAM, power system, USB camera,3G wireless network card, SD card and GPS module. The software system of video surveillance terminal based on embedded Linux system. The functions need to finish on the embedded Linux system, include: achieve GPS information，capture surveillance video stream, encode the video stream into H.264，store video files in SD card, package video stream in RTP(Real Time Protocol) format, and transfer the RTP packages to the surveillance terminal through3G wireless network In UDP protocol.The surveillance terminal is designed in Qt creator IDE, and works on the Windows operating system. First, surveillance terminal need receive the RTP packages. Then unpack these packages. Then make use of FFmpeg decode the H.264stream. Last, display the video on computer screen.For the purpose of reducing the cost of3G traffic, there are two modes has been designed. The surveillance front-end will encode the video stream in low bit rate for3G transfer when monitoring personnel find nothing abnormal cases. If monitoring personnel find any abnormal cases, he can switch the mode into the other mode encode in high rate through transfer a command by the surveillance terminal. The terminal can control the work mode of system front-end via send control commands through the network. In order to examine the surveillance video, the system will always store the high bit rate video in SD card.