Research On Mobile Video Surveillance System

With the development of the network technology,digitalized and networking video monitor system enables the surveillance of the important place through the network without any limitation,which brings vitality to the field of the safety and protection.Network surveillance based on the wireless LAN is normal used in small area monitor,e.g.production department,residence community.Composed of wireless facilities supporting IEEE802.11a/b/g standard,the connection rate of the surveillance system can reach as far as 11,22,54Mbps or more.The system based on wireless LAN can guarantee the bandwidth for video transmission with reliable and stable performance.Compared with the cable surveillance system,the wireless system saves the work of wiring,brings no destruction to the environment,which cuts down sharply the construction period and improves the cost-benefit.It is convenient to make adjustment to the arrangement of monitoring points.This thesis firstly introduces the key technology utilized in the mobile video surveillance system,then analyzes in detail the objective of the system,and determines the technology pathway.This system is composed of video collection component,server component,wireless network and mobile facilities.Cameras and video capture cards are adopted to collect the video and perform the A/D transformation.At server side the video data is encoded into stream media using Windows Media Encoder technology after the motion detection and MPEG-4 compression,and encapsulated into RTP data package and broadcasts to the WLAN client side based on the IEEE802.11g architecture.The client components in WLAN use Windows CE based hand-hold mobile equipment.The mobile equipments are responsible for the receiving,decoding and broadcasting of the video data.Double buffering technology is adopted during the receiving process to eliminate the effects of network delay and tremble.Receiving and transmitting of the video data are realized through the multi-threading technology.Development of the system described in the thesis involves Microsoft DirectShow and Windows Media Encoder technology,Socket programming,and especially focuses on the IEEE802.11g wireless network broadcasting and MPEG-4 and WMV coding technology.A flame differencing algorithm is accomplished to detect moving objects.Client environment based on Windows CE operation system, the thesis should use.net compact frameworks to accomplish the function of client.