【作者】 丁晖；

【导师】 李德华；

【作者基本信息】 华中科技大学 ， 模式识别与智能系统， 2006， 硕士

【摘要】 近年来,随着计算机、网络以及图像处理、传输技术的飞速发展,数字图像采集与通信系统也逐渐的开始向嵌入小型化和网络化方面发展。同时,嵌入式系统的发展非常迅速,其应用也越来越广泛,而由于Linux系统其稳定性与安全性以及成本低的特点,越来越多的企业和用户将Linux系统作为各类服务器的首选操作系统。而且,CDMA 1X无线通信网络以其覆盖范围广、使用费用低、技术完善、安全可靠性高等优点,当之无愧地成为现代通信技术业务信息化中的重要资源。基于以上原因及实验室项目开发的需求,本论文着重对基于CDMA 1X网络,在Linux系统下实现图像采集与无线通信系统进行研究与开发。首先考察了国内外图像采集与无线通信技术的发展情况和研究动态,针对嵌入式微处理器和嵌入式操作系统的现状和发展趋势,提出了将XScale处理器和嵌入式操作系统Linux相结合的设计方案,并建立了Arm-Linux交叉开发环境,定制了我们需要的最小的Linux内核。其次,对USB摄像头在Linux系统下图像采集进行研究并加以实现。数字图像的压缩是数字图像采集系统小型化和网络化的前提。分析了系统图像采集的需求及图像压缩的相关理论和技术,使用了JPEG压缩技术作为该采集系统的压缩方法,并就系统的硬件部分和软件部分设计和实现开发分别进行了详细分析和论述,主要包括USB图像采集硬件构成框图、加载驱动及V4L模块、使用C语言实现图像采集与压缩编解码和软件的移植。再次,对嵌入式系统下无线通信系统进行研究与设计。对CDMA 1X技术进行了详细的讨论,对比分析了CDMA 1X、GPRS的优缺点,给出了通信系统终端的硬件设计,介绍了PPP协议的原理,系统的阐述了通过PPP拨号上网的通信流程。最后,讨论了网络传输的研究与实现,阐述了Linux的网络层次结构、TCP/IP协议、Socket编程及最基本的API函数,并给出了图像压缩数据的网络传输与监控中心应用程序的软件实现。更多还原

【Abstract】 In recently, with the fast development at computer, network, image process,communication and transmission technology,digital image acquisition system is now developed in the direction of embedded miniaturized and network system. Meanwhile, embedded system develops rapidly and it is applied more widely,and that because Linux system is a steady, safe and low-cost operation system,more and more enterprises and users take Linux as the server’s chief operating system.Furthermore,CDMA 1X network becomes the important resource in modern communication technology information area. Thus, we propose and design a video image capture and wireless communication system under Linux system based on CDMA 1X network.Firstly, this thesis investigates the development and research of world’s video capture and wireless communication technology,and introduces the development of embedded micro processor and operating system,then the thesis presents a design scheme, which is composed of XScale micro processor and embedded operating system Linux, and then sets up Arm-Linux cross development environment,and customizes the minimum Linux kernel that we need.Subsequently, the key technology of video capture in using USB camera under Linux system are discussed. Compression of digital image is the precondition for the miniaturization of digital image acquisition system. This thesis analyzes the video technology and interrelated compression theory, selects JPEG (Joint Picture Experts Group) compression technique for this system, and discusses in detail about how to develop the hardware and the software of system, including hardware frame of USB video capture, loading drive and V4L module, video capturing and compression in C program language and software transplant.Followingly, the wireless communication system in Linux system is discussed and designed.Furthermore detailedly discussing CDMA 1X network technology,contrastively analyzing CDMA 1X and GPRS (General Packet Radio Service), providing the reason of selecting CDMA 1X network.Then this thesis marks out the hardware design of the communication system terminal,introduces the principle of PPP (Point-to-Point) Protocol, and the working flow of wireless access Internet based on CDMA 1X.Lastly, the thesis discusses the research and realization of network transmitting, introduces the Linux network hiberarchy,TCP/IP protocol,Socket programming and basic API function.And then the application software realization scheme is presented about the video compression data transmitting and monitoring center.更多还原