Design And Implementation Of Wireless Video Moniotring System

With the development of the times and technology, the requirements of quality of life isincreasing, more attention is paid to the inner security. Video monitoring system is one of thesecurity measures in people’s life and production, and also an important part of protecting thesafety of people’s property and life. Video monitoring system can be seen everywhere in life,such as the bank’s ATM machine, traffic regulatory, supermarket consumption monitoring,community security monitoring, even forest fire prevention and study for animals’ behavior.Video monitoring system has gone through three stages in the past30years. Now videomonitoring system is widely used in various fields and closely related to people’s life. Videomonitoring system is developing mainly towards the direction of high-definition imaging,intelligent monitoring and networked transmission.The wireless video monitoring system belongs to the third generation of videomonitoring system. It is composed mainly by multiple capture terminal, wireless transmissionnetwork and monitoring terminal. When working, each part responsible for different taskscooperates with others. The system selects Friendly-ARM mini2440board with SamsungS3C2440processor as capture and monitoring terminal, embedded development technologyas the core, combining with V4L video capture technology, FFMPAG video codec technology,wireless WiFi technology, RTP/RTCP network transport protocol, Qt graphical interfacedevelopment framework. The system is designed and implemented based on the systemrequirements obtained by user research. Regardless capture or monitoring terminal, the wholesystem inherits the characteristics of embedded system, that is cropped hardware andsoftware, lower cost, higher reliability and performance, stronger scalability. Portability andconvenience is also indispensable. Because of the usage of wireless transmission network,users are not subject to the constraints of fixed working location. As long as the network-wide,users can monitor the target anywhere and anytime, getting rid of the shackles of cable andeliminating the need for additional wiring overhead.In the system, the video capture terminal captures the images by camera and encodes theimages before sending to the video monitor terminal through a wireless card. Videomonitoring terminal receives the images over transmission, decodes the images and finally displays the images on the device terminal. Images can be displayed in two ways, one issingle full-screen play, the other is multiple split-screen play. Users can perform operationssuch as screenshot, period save and playback when video images play. Video monitoringterminal also contains some auxiliary applications, for example, clock and notepad.The paper firstly introduces the status and development trend of video monitoringsystem, and does the research of related technologies as well. Analyze the systemrequirements obtained by the user research by combining with the actual situation. Determinethe function and complete the modular division based on the requirements. Then design thehardware and software system architecture in detail, implement and test video decodingmodule, video display module as well as auxiliary applications.Video decoding module mainly applies FFMPEG techniques, implementing decodingprocess for compressed media stream transmitted from the capture terminal. Theimplementation process includes decoder registration, media stream extraction, decodermatch, resources application and release and media stream decoding. Combined with the Qtframework, call the external implemented decoding module through the QProcess class.Video display module implements single full-screen and multiple split-screen displaymode by Qt multithreaded mechanism, as well as some monitoring auxiliary functions likescreenshots and period preservation. Finally test the module function by visual senses, framerate analysis and system operating efficiency.The paper finally talk about the process of building system development environmentand system migration, summarize the work and outlook the system.