节点文献
基于嵌入式Linux的图像采集系统的设计
Design of Image Acquisition System Based on Embedded Linux
【作者】 赵智雅;
【导师】 王泽勇;
【作者基本信息】 西南交通大学 , 物理电子学, 2010, 硕士
【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。
【Abstract】 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.