| As an important member in the area of monitoring, video monitoring system which hasalways became the focus of attention has been widely used in many areas. Video monitoringsystem has many particulars, such as intuitive, convenient, easy to control, high timelinessand so on. Thanks to these particulars, video monitoring system has been the main way in thearea of monitoring. Recently as the popularity of wideband, the improvement of imageprocessing and the improvement in informatization of society, the area of video monitoringsystem is getting wider and wider. Thanks to the continually improving in the areas ofembedded technology, transmission in network and digital image processing, videomonitoring system has been getting rapidly development, and showed the development trendinto digitization, intelligence and network.Wireless video monitoring system belongs to the latest generation video monitoringsystem, the system combined with embedded technology perfectly. The system with manyparticulars such as small size, low cost and high timeliness, it has been the hotpot in the fieldof monitoring and used in some fields. With the help of wireless video monitoring system,monitor can move freely and realize the remote monitoring by handheld terminal. Theappearance of wireless video monitoring system based on embedded technology solves theproblems of complex structure, low stability and low cost-effective in the traditionalmonitoring system based on PC.This paper has developed wireless video monitoring system based on S3C2440embedded processor. It can realize the real-time split-screen monitoring and changeablemulti-channel full screen monitoring. The system has many advantages such as small size,low cost, high timeliness and so on..This paper designed the total system structure according to the need of function in thissystem, and designed the hardware and software architecture based on the specific needs. Onhardware architecture, considering the factors of particular in this system and thecost-effective in devices, finally chose some related hardware devices. This paper has chosenARM9series embedded processor S3C2440as the core device, chosen digital camera basedon Zc301chip as collecting device, chosen wireless network card based on RT3070chip aswireless transmitting device, chosen NEC7.0inch TFT LCD touch screen as video playingand interacting device. In the meanwhile, did some expansion in peripheral devices such asFLASH，RAM and so on. On software architecture, this paper planned the overall softwaredesign program and divided the whole system into some modules. This paper chose Linux asthe operating system for the development board and did some relative work in this operating system to meet the system such as kernel cutting and file system selecting. Based on thisoperating system, this paper did the detailed design for each of the modules. The programsdeveloped in this paper are based on open source technology which is including V4L, SDL,RTP, FFMPEG and so on.The system designed in this paper can be divided into two parts, they are captureterminal and monitoring terminal. The part of capture terminal may consist of several captureplatforms, while the monitoring terminal has only one terminal device. The main function ofcapture terminal is collecting image information of monitoring point then send theinformation to the processor of capture terminal to encode it, finally send the encoded imageinformation to monitoring terminal through wireless transmission device. After receiving theencoded image information, the processor of monitoring terminal will decode the informationto original video data. Then the original video data could be played on screen by multi-screenmode or full screen mode. According the summary of above, the system can be divided intofour modules, they are video capturing module, video decoding and encoding module, videoplaying module and video transmitting module. This paper will mainly introduce the firstthree module in detail.The main function of video capturing module is collecting image information through adigital camera, then save the information into memory. This paper adopted the interface ofopen source technology V4L to capture image data. The function of capturing ismemory-mapped and double-cache so that improving the efficiency of capturing; videodecoding and encoding module is responsible for encoding and decoding the image data inorder to reduce transmission bandwidth and save storage space, this paper used the opensource technology FFMPEG to realize the decoding and encoding work, the standard ofcompression is MPEG-4; the function of video playing module is playing the original videodata onto LCD screen, the module is based on open source technology SDL. The system hastwo kinds of playing mode, one is multi-screen playing mode, this mode is based onmulti-thread technology, the other one is single full screen mode.This paper analyzed the functions needs of the wireless video monitoring system simply,and designed the detailed hardware and software architecture. It divided some parts offunction modules for the system and gave the specific solution for each module. Finally, thispaper realized all of the functions of this system on embedded development boards.According to some experiments, I got a satisfactory result. |
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