Research And Design Of Wifi-based Triggered Wireless Image Acquisition System

With the embedded technology, image processing and network communication technology continues to evolve, video surveillance system has become to be more and more useful in people's productions and lives. With the widely use of video surveillance system, its shortcomings has been exposed. Because the image capture side has to transmit the image data to the remote computer all the time, while the network resource has been occupied, this process has also been a waste on power resources. And among the images returned, we do not care most of them, which result in waste of network and power resources, while also increasing the amount of storage of image data and the difficulty of the video images analysis.This design of wireless image acquisition system is triggered, the meaningless images will be decreased on the capture side, in order to address the waste problem of network and power resources. The system can be combined with an external monitoring system to form a new triggered wireless image acquisition system which can monitor a particular volume.With the development of image processing technology, the new generation of video surveillance system, which using the image analysis processing program as an external monitoring procedure, and combine with the system this paper designed ,will be able to satisfactorily resolve the problem of wasting resources. The new system captures images through the video capture device, and then the image will be analyzed in place. When the live coverage meet the monitoring requirements, the image analysis processing program will send a request to the system this paper designed, then the system will send the scene picture from the system in a timely manner to the computer to save it.After studying series of related technologies, this paper has designed the hardware and software system architecture of this triggered wireless image acquisition system. The core board of this system is S3C2440, peripheral devices are the wireless transmission module (the main chip is RT2571WF) and image acquisition module (the main chip is OV9650). Operating system is Linux. Software architecture is divided into two parts, client and server. The client node is running on the image acquisition, and the server is running on a remote computer. According to function, the client part is divided into three levels: the pipe communication layer, camera film layer and the network transport layer. Pipe communication layer is responsible to view named pipes and receive requests from the external monitoring systems. The camera recording layer is responsible for starting and initializing image acquisition equipment, and acquiring the image. The network transport layer is responsible to return the images to the remote computer. The server will name the file with the local time which is used to save the image information on the computer when it receives the image information.In addition, we implemented a simple model of the system and tested the usability of the model. And through test program, we made a rough study of the model in real time. The reason of the model being said "easy" is that it is composited by the hardware modules which are common packaged products on the market: core board for mini2440 development board, the wireless transmission module for the RT2571 module, image acquisition module for the rapid Diamond V7 camera. After testing, the availability of the model is good, the real-time is comparatively good.This system can simple combined with an external monitoring system. The external monitoring system has only to write the named pipe specified in the system with an agreed string to request that the system functions. The triggered wireless image acquisition system not only has a positive meaning for the technological of video surveillance system, but also can play a supporting role in other areas.