| Visual image information which account for more than70%of the proportion is the most important source of information people obtained from outside. The amount and the accuracy of information provided by the image is far from achieved for language and text description. The video surveillance systems which provide intuitive, vivid, rich and accurate image information have been widely used in modern society, and they have brought great convenience to people’s work and life. As video surveillance systems used more widely, people’s requirement of the function of video surveillance systems is increasingly high. However, there are a lot of limitations in traditional video surveillance systems, such as the complex structure, low stability, expensive, and the limited transmission distance.Embedded systems are special computer systems which are applied in special occasions where there are special requirements on function, size, cost, reliability and power consumption. They are application-centric, and their hardware and software can be cropped. In recent years, with the continuous development and improvement of the embedded microprocessors and embedded operating systems, embedded devices are more and more powerful. They are widely used in industrial manufacturing, process control, network communications, instrumentation, automotive, shipping, aviation, aerospace, military equipment and consumer electronic products in various fields.With the video surveillance systems develop to digital, integrated, networked and intelligent, video surveillance technology based on embedded technology as an advanced and cheap video surveillance technology, provides a new solution of surveillance equipment. Compared with the traditional video surveillance systems, video surveillance systems based on embedded technology and network has many advantages:fully digital, the camera output processed digital video data directly; their distributed structure are more reasonable and their function can be extended easily; they are more intelligent, the cameras have powerful data processing and network communications capabilities within the embedded microprocessor and embedded operating system; their data are more security, the video signals can be encrypted, and you can also add digital watermarks in the video information to ensure their safety.In this paper, we use embedded technology, image processing technology and wireless transmission technology to design a kind of compact, cheep, good stability embedded digital video surveillance system. This system uses the S3C6410 microprocessor and Windows CE6.0as the main controller and operating system. It uses USB camera to capture image data. It uses the Multi-Format video Codec which is integrated in S3C6410microprocessor to encode the video data in H.264format. It uses wireless network to transmit video data. Managers can view the video received by client software.We need to complete the following work in this paper:(1) We need to build the hardware platform. In order to speed up the progress of the development, we use isolated core board and isolated floor board to build the hardware platform. We choose Tiny6410core board which is produced by Friendly ARM computer technology Co.Ltd. as the core board. We build the hardware platform by extending necessary interfaces based on the core board such as USB interfaces, SD card interface and so on. We choose USB camera within vimicro301PLUS controller as the image capture module, choose USB wireless card within Ralink2070chip as the wireless transmission module. They can be fixed and maintained conveniently.(2)We need to study the principle of work of Windows CE6.0operating system, and design the BSP for the target hardware platform on the basis of the reference BSP provided by SAMSUNG. We need to transplant the Windows CE6.0operating system to the target hardware platform, and design the drivers for the devices of the target hardware platform.(3) We need to analysis the stream interface driver model and the USB system software architecture of Windows CE6.0operating system, and design the driver entry point functions and the stream interface functions, complete the development of the driver for USB camera.(4) We need to analysis of the directory structure of Platform Builder6.0and the usage method of the Platform Builder6.0to customize the Windows CE6.0operating system. We need to choose the appropriate components to customize the proprietary operating system which meets the requirements according to the needs of the subject. We need to write the image file of the operating system generated by compiling the source code to the Flash memory of the target hardware platform. We need to start the system and test the compatibility and stability of the operating system and hardware platform.(5)We need to study the principle of work of the MFC in S3C6410chip, design the software for the server to capture, encode and transmit the video data refer to the H.264driver provided by SAMSUNG. (6)We need to design the software for the client to receive, decode and display the video data.In the actual test process, the client can still receive and show the video smoothly when the resolution choose640*480and the frame rate choose25in the open environment no more than50meters, and the frame rate actually received is at about25frames per second. So this video surveillance system can meet the requirements of most ordinary users. But the performance of the system will decline and the packet loss rate will increase in the case of walls and other obstructions, and the frame rate received will be at about20frames per second. So this video surveillance system basically achieve the desired objectives, it can meet requirements of the ordinary families and small businesses who demand less on equipment performance but take cost seriously. |
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