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嵌入式无线IP Camera设计与实现
The Design and Implementation of Embedded Wireless IP Camera
【作者】 杨经纬；
【导师】 杨斌；
【作者基本信息】 西南交通大学 ， 密码学， 2008， 硕士
【摘要】 近年来,随着嵌入式计算机系统的迅猛发展,其应用已经深入人们日常生产和生活的各个领域。而嵌入式数字视频与流媒体技术也同时得到了快速发展和应用。鉴于视频监控技术已进入以嵌入式技术为依托的网络视频监控系统的新阶段,本设计基于S3C2410A处理器,对嵌入式系统在视频监控领域的应用做一个实践,开发出一款支持无线网络的IP Camera。本设计以S3C2410A为硬件核心为IP Camera设计了印制电路板,主要包括:4组DC-DC电源供电模块、4个USB主口、1个USB从口、3个RSR232串口、JTAG调试接口、实时时钟供电模块、复位电路、系统总线驱动及扩展电路。同时,还支持以太网接口、PCMCIA/CF接口、IDE接口、SD/MMC接口、触摸屏与LCD、音频、ADC等。丰富的外设资源以及高性能低功耗的处理器平台为IP Camera的实现提供了较好的硬件支持,也为系统整体方案的确定提供了多种可能。为了提高系统可靠性,印制电路板的设计采用了4层板布线,系统运行更加稳定。本设计根据实际需求,开发了一个比较易用的BootLoader,具备了一系列的必要功能,满足了系统开发的需要。本设计还移植了2.4.18版的Linux内核到硬件平台,运行效果稳定良好,这为IP Camera的上层应用开发提供了一个更加良好的编程接口,同时移植和开发的驱动程序也为应用提供了更加简单抽象的硬件接口。对于IP Camera的上层应用,为其开发了具体的实例,采用Socket编程技术,基于Linux V4L的视频采集和视频处理等Linux下高级应用实现了IPCamera的网络摄像功能,用户在客户端通过监控界面即可观看摄像头所采集的图像。Linux下基于PCMCIA接口的802.11b无线网络接口也是本设计的难点部分,本文最后还探讨了视频流的采集、MPEG-4压缩以及加解密技术。最后,本文给出了在实验室特定测试环境下的测试数据和实验结果,在系统设计工作总结中,分析了设计的不足和尚需改进之处并对将来的工作作了展望。本设计遵循一般的系统开发流程,按照预定的实现目标设计并开发了这样一种无线IP Camera,具有一定的理论和实用价值。
【Abstract】 During recent years, as embedded computer system developes rapidly, it has been applied everywhere in people’s life and work, in the meanwhile, digital video surveillance and multimedia technology on embedded computer system also has gained rapid development speed and widespread application. Since video surveillance has entered a new time when it bases on embedded computer system and networks, this designe plans to develop an embedded wireless IP Camera basing on S3C2410A, which is to be used in video surveillance.This design has made a print curcuit board for IP Camera basing on S3C2410A, which includes 4-ch DC-DC power supplier, 4-ch USB host, 1-ch USB device, 3-ch UART, JTAG ICE, system bus drivers, system reset curcuit and so on. Also, the board supplies interfaces for 10/100M ethernet, PCMCIA/CF, IDE, SD/MMC, Audio, ADC, touch screen and LCD. These all make a good hardware support for the IP Camera and give various choice for the implementation. With the purpose of the print circuit board’s stabilization, it is designed with four board layers.A BootLoader for S3C2410A platform has been developped, with a serial of necessary functions, which has well met the demands of IP Camera. The Linux kernel of version 2.4.18 has also been ported to IP Camera, which supplies many APIs for the application. The drivers ported with kernel make it easier to drive the hardwares of IP Camera in user programs.An application software has also been developped for IP Camera, which makes its video capture function to become real beings. The application mainly bases on the technology of V4L, socket communication and 802.11b wireless LAN protocol. User with a client GUI software can then get a view of the video pictures from IP Camera through networks. The interface of PCMCIA/CF, through which S3C2410 communicates with wirelss LAN card, is a key and hard part of the design. The detail of video capture,MPEG-4 and encryption/decryption are discussed at the end of this thesis.At last, this thesis gives out the result of test for IP Camera and finds out room for further development, meanwhile, it suggests a plan for it too. Following standard development process, the embeded wireless IP Camera developped in this design has some theoretical and practical value according to the present goal.