摘要
嵌入式图像采集系统所具备的灵活性、软硬件可裁剪性、体积小型化、成本低、功耗低和片上系统的特点,不仅适合于通用性强的图像采集,而且在铁道监控和安全检测等方面有着广泛的应用。
列车轮对探伤和尺寸检测是铁路安全检测的一个重要组成部分,其中,对轮对图像的采集、传输及后续的图像处理技术能够很好地探测和发现有伤的车轮,并且能够检测轮对的外形尺寸,所以轮对图像的采集是较为重要的一项工作。
本文正是在这样的背景下设计并实现了一套图像嵌入式采集系统。通过大量调研国内外已有的图像采集系统,本文选择了嵌入式技术来设计整套系统,它是利用ARM技术和Linux技术来进行图像的采集。
整个图像嵌入式采集系统主要由硬件系统和软件系统两部分组成。硬件系统由嵌入式微处理器、外围接口电路、摄像头、LCD显示器和远程计算机等组成,前端摄像头负责对在线的车轮进行图像采集,然后将采集到的数据传送回开发板,再由开发板负责将数据实时传送至其上指定的显示缓冲区用以完成在LCD上的图像实时显示,最后将图像数据通过网络上传至远程计算机。软件系统由嵌入式操作系统和应用软件组成,嵌入式操作系统建立在硬件平台基础上,操作系统用来驱动系统的硬件设备,并给应用软件提供运行环境和接口,应用程序建立在操作系统上,是实现嵌入式图像采集系统各种功能的主要部分,包括图像采集与显示、图像压缩等。
本文在确定图像采集系统方案后,重点进行了系统的硬件平台设计、嵌入式Linux操作系统的建立以及图像采集与显示程序的设计。本系统硬件平台设计方案采用核心板加外围设备的方式。核心板采用的CPU为Samsung公司的$3C2440A芯片,以此为基础在核心板上集成了一些必要的外围资源。外围设备主要包括:USB摄像头、输入设备(键盘)、LCD显示屏、远程计算机。图像采集功能是在基于OV511芯片的USB摄像头的基础上进行的,利用Video for LinuxAPI函数接口,即可完成图像的采集。
在完成了系统软硬件设计之后,进行了现场系统实验。实验结果表明,本套系统能够完成图像嵌入式采集,达到了设计的预期目的。
The system of embedded image captured has some characteristics, such as flexibility, software and hardware modification, mini-bulk, low cost, low power and system on chip. So, it not only adapts to general image acquisition but also has wide applications on the aspects of railway surveillance and secure inspection.
It is an important part of railway detection to detect the wheel's scrape and to measure the wheel's size. It could find the scrape wheel and measure the figure size of wheel well through capturing the wheels image, transmitting image and processing image, so it is an important task that capturing the wheels image.
An image captured embedded system was designed and implemented on the background in this paper. After vast researches of the existing image captured system home and abroad, this paper designed the whole system by embedded technology, it made use of ARM and Linux technology for capturing the wheels image.
It is composed of two important parts in this image captured embedded system, including hardware and software system. The hardware system consists of embedded microprocessor, interface circuit, camera, LCD and remote computer. The front-end camera takes responsibility of capturing wheels image, then it sends the acquired data to the development board, the board takes responsibility of sending the data to the assigned display buffer in real time for completing image displayed on LCD. Finally, image data was send to remote computer by net. The software system is made up of embedded OS and application software. Embedded OS is build up on hardware platform for driving hardware and providing moving environment to application software. Application program is build up on OS for realizing the every function of embedded image captured system, including image captured, image displayed and image compressed.
After confirmed the scheme of this image captured system, it has designed the hardware platform of the system, has build the embedded Linux OS and has designed the program of image captured and displayed as three important parts in the paper. This scheme of hardware platform of the system was made up of core board and equipments around. The core board has a S3C2440A chip which was produced by Samsung as a character of CPU, and based on that the core board was integrated with some necessary resources around. The equipments around was composed of four parts, including USB camera, keyboard, LCD, remote computer. The function of capturing image would come true because it is based on USB camera which has a OV511 chip. Through making use of the function interface of Video for Linux API, the image captured was done.
After finished the hardware and software design of the system, system experiments were done. The results of the experiments indicate that the system can accomplish embedded capturing of the image, and reach the anticipated purpose.
引文
[1]佟雨兵,常青,张其善.嵌入式CCD视频图像采集系统.光电工程.2004年12月第31卷增刊:133-136
[2]王振煜,葛万成.嵌入式高分辨率图像采集系统的设计与实现.计算机技术与发展.2008年2月第18卷第2期:167-169
[3]刘斌兵,刘云海,汪燮彬.用FPGA实现高速大图像采集系统.电子技术应用设计.2006,1:60-63
[4]许明流,邓王国,刘智勇.基于嵌入式Linux视频图像采集系统的设计与实现.福建电脑.2008年第7期:153-154
[5]刘鑫.基于ARM的图像采集系统的设计.武汉理工大学硕士学位论文.2007
[6]Stephen Balacco, s Lanfear. Linuxs Future in the Embedded SystemsMarket. Industry analysts, Venture Development Cooration,2002
[7]商斌.嵌入式Linux C语言开发入门与编程实践.北京:电子工业出版社.2008,5:6-10
[8]刘万志.基于ARM9的图像采集系统设计.北京交通大学硕士学位论文.2008,5:12-14
[9]鲁力.嵌入式图像采集系统的研究与实现.武汉理工大学硕士学位论文.2006
[10]孟超,张曦煌.基于嵌入式系统的图像采集与传输设计.计算机工程与设计.2008年9月第29卷第17期:4414-4416
[11]刘飞.基于USB摄像头的嵌入式图像采集系统的研究与实现.江南大学硕士学位论文.2008,7:3-4
[12]陆云昆,张承业.嵌入式Linux下的视频和图像采集.嵌入式系统编程.2006,12
[13]许振山,刘峥嵘,张智超.嵌入式Linux应用开发详解.北京:电子工业出版社.2007,11:2-13
[14]张文涯.Linux系统下USB摄像头驱动多缓冲与图像采集研究.电脑知识与技术.2008,11第4卷第6期:1485-1488
[15]赵炯.Linux内核完全剖析.北京:机械工业出版社,2009
[16]李善平,施韦,林欣(译).LINUX教程.北京:清华大学出版社,2005
[17]赵昌永.基于嵌入式Linux的视频采集系统设计.浙江大学硕士学位论文.2005,6:6-9
[18]韩相军,关永,王万森,王雪立.嵌入式视频采集系统的设计与实现.微计算机信息.2006年第22卷第1期
[19]梁丁,熊建,王录涛.ARM微处理器与应用开发.北京:电子工业出版社.2007,8:25-53
[20]Steve Furber. ARM System-on-Chip Architecture. Addison-Wesley. Second Edition.2000
[21]David Seal. ARM Architecture Reference Manual. Addison-Wesley. Second Edition.2001
[22]Li, Hai-Yan, Li, Xin-Ming. Embedded operating system design:The resolved and intelligent daemon approach. Lecture Notes in Computer Science. v3605 LNCS.2005:412-417
[23]常丹华,南进,陈丽娟,韦青,程德芳.基于嵌入式平台和USB2.0的高速线阵CCD图像采集系统.电子测量技术(数据采集).2008,31(3):97-100
[24]吴晴,周健.嵌入式图像采集系统的设计与实现.电子测量技术.2007,30(6):90-92
[25]马志晶译.S3C2440A 32位CMOS微处理器用户手册.2007
[26]Omnivison.OV511 Data Sheet Rev.1.0.1998.
[27]张绮文,谢建雄,谢劲心.ARM嵌入式常用模块与综合系统设计.北京:电子工业出版社.2007:153-155
[28]武秀文.基于ARM嵌入式平台的图像处理系统.武汉理工大学硕士学位论文.2006
[29]Antoniotti, Marco, etc. Embedded system design specification: Merging reactive control and data computation. Proceedings of the IEEE Conference on Decision and Control. v4,2001:3302-3307
[30]陈亮,裴海龙,伍越.基于Video4Linux2的图像采集程序设计.微计算机信息.2009年第25卷第3-1期:65-67
[31]广州友善之臂计算机科技有限公司.QQ2440V3用户手册.2008:142-162
[32]刘爽.基于ARM和Linux的嵌入式CCD相机采集系统研究.电子科技大学硕士学位论文.2006
[33]李晓光,吉荣廷,张立峰.基于嵌入式Linux和ARM9的视频采集系统.电 子测量技术.2009年2月第32卷第2期:102-104
[34]潘春鹏.基于嵌入式Linux的视频信号实时采集系统的设计.重庆大学硕士学位论文.2007,4:38-45
[35]戴丽.基于Video4Linux的图像采集系统研究.合肥工业大学
[36]谭浩强.C++程序设计.北京:清华大学出版社,2004
[37]魏永明,耿岳,钟书毅(译).LINUX设备驱动程序.北京:中国电力出版社,2005
[38]赵永勇,张永健.基于Video4Linux的视频图像采集实现.电脑编程技巧与维护.2006,5:75-77
[39]张秋野,黄佩伟,褚蓓.嵌入式Linux平台下USB接口的视频设备驱动技术.信息技术;2006年第7期:73-75
[40]Wang J. Q., Chen T. Embedded data acquisition in vehicle electronic system. Journal of Beijing Institute of Technology (English Edition), v 9, n 4, December,2000:403-407
[41]王滔,季晓勇.在嵌入式Linux平台上使用USB摄像头.微计算机应用.2006年1月第27卷第1期:52-54
[42]杨磊.基于嵌入式Linux视频采集平台的开发.武汉科技大学硕士学位论文.2008
[43]Kirk Zurell. C Programming for Embedded Systems. CMP Books. Feb, 2002
[44]Michael H Schimek, Bill Dirks, Hans Verkuil. Video for Linux Two API Specification Draft0.13. mschimek@gmx. at. April 2006
[45]Alan Cox. Video4Linux Programming. alan@redhat.com.2000
[46]王培珍,徐俊生.基于ARM9的嵌入式Linux图像采集系统设计.中国制造业信息化.2007,16:85-88
[47]Iain Richardson. H.264 and MPEG-4 video compression, video coding for next-generationm ultimedia. Wiley, UK.2003
[48]刘兴建.基于嵌入式Linux的图像采集系统研究.武汉理工大学硕士学位论文.2008
[49]郭剑.基于嵌入式系统的数字图像处理技术的研究.西安电子科技大学硕士学位论文.2006