【作者】 王彩霞；

【导师】 尹福昌；

【作者基本信息】 长春理工大学 ， 光学工程， 2009， 博士

【摘要】 本文以吉林省科技厅项目(项目号:20070325)及31基地项目激光XXXXXX系统为依托,对嵌入式激光光束质量分析系统做了系统地研究,探讨了激光光束质量测量的相关理论和评价方法,详细论述了嵌入式图像处理技术及嵌入式激光光束质量分析系统图像处理平台的构建,分析了系统各单元性能对测量精度的影响,并介绍了激光光束质量分析系统的研制和实际应用。简单分析测量激光光束质量的意义,分析了目前激光光束质量测量中采用的几种常用方法,通过比较各种方法的使用范围和优缺点,提出了把光束质量因子法即M~2因子法作为本系统评价激光光束质量的主要方法,具有评价精度高、综合考虑激光光束近场特性和远场特性等优点。在回顾和总结高斯光束传输与变换特性的基础上,详述了激光光束传输特性参数测量的基础理论和方法,介绍了二阶矩、光束参数积、衍射极限倍率因子和光束传输因子等激光光学基础概念及其物理意义;介绍了ISO标准文件规定的激光束参数测量步骤、评价方法和相关光束质量因子计算公式。在研究激光光束质量评价理论基础上,本文提出了面阵数字CCD技术、嵌入式技术及现代专用集成电路技术相结合实现嵌入式激光光束质量分析系统的方法。研究了嵌入式图像处理技术,介绍了嵌入式图像处理系统的应用、嵌入式Linux操作系统及嵌入式图形用户界面,并重点探讨了本系统设计时采用QT/Embedded编程的关键技术,在综合以上关键技术的前提下,设计了嵌入式激光光束质量分析系统图像处理平台,主要包括建立嵌入式交叉编译环境、移植引导加载程序、进行嵌入式Linux的剪裁与移植等工作。在分析系统中影响激光光斑图像质量的主要因素后,重点阐述了嵌入式处理器运行去除图像噪声中值滤波算法、图像灰度抖动消除算法、帧平均等算法如何处理激光光斑图像信息,减小系统测量误差。系统硬件单元的研制工作主要包括:光学衰减、聚焦及反射光学系统的设计;精密机械部件的研制;步进电机控制、激光光斑图像数据采集、存储、传输单元、图像处理和显示等电子学系统研制。较好的解决了图像数据采集和传输中现场门阵列缓存,直接存储器存取方式数据传输的关键技术,对系统各个部件的精密装配、联调和测试表明:该系统能够精确、快速的测量激光器光束质量,直观地给出激光光束质量M~2因子的值、束腰直径、束腰位置、束散角、激光光斑的二维、三维分布和光斑形状等重要激光光束特性。嵌入式操作系统技术的采用提高了系统的实时性,所以,本系统能实时、快速地测量出激光光束质量,真正意义上实现了激光光束质量的实时测量。综上,论文用矩阵方法研究高斯光束通过薄透镜的传输和变换性质,以及高斯光束的特性参数,重点对光束质量的评价和测量进行了阐述,采纳国际标准制定的测量建议,建立了一套以数字CCD为光斑探测器,结合嵌入式处理器和现场可编程门阵列技术的激光光束质量分析系统。最后,应用该系统测量了氦氖激光器激光光束光强分布,用二阶矩积分法计算出激光光束参数,并用双曲线拟合法测量出光束质量因子,对采集光斑进行背景相减去噪、多帧图像数据平均消除抖动以及高斯拟合得到了比较完整的光强分布信息。嵌入式激光光束质量分析系统的研究为激光器出射激光光束质量的检测提供了有效手段,为激光光束质量测量仪器的便携式、小型化发展提供了理论依据和实践基础。本文对研制开发的嵌入式激光光束质量分析系统进行了大量实测,测量数据表明:该系统随机误差小,测量误差的重复性、再现性较好,束腰处M~2因子的测量精度小于4%。更多还原

【Abstract】 The paper did researches on laser beam quality analyzing system systematicaly based on the project whose number is 20070325 from Jilin province science and technology bureau and the project called laser XXXXXX system from 31 military base, discussed the corresponding theory and evaluation method about laser beam quality measurement, expounded the embedded image processing technology in detail and the construction of image processing platform for the embedded laser beam quality analyzing system, analyzed how each unit’s performance affected the measurement precision and introduced the development and the action of laser beam quality analyzing system.Analyzed the significance of research on laser beam quality measurement and the common methods used in laser beam quality measurement, proposed the beam quality factor method which is also called M~2 method as evaluation method for the system designed in the paper by comparing their using range, advantages and disadvantages, the method proposed in the paper had advantages such as high evaluation precision, synthetical consideration including laser beam near field characteristic and far field characteristic synthetically and so on.The paper stated fundamental theories and methods for transmitting characteristical parameter’s measurement of laser beam based on reviewing and summarizing Gauss beam transmitting and transformation properties, introduced conception and physical meaning for second order moment, product of laser parameter, diffraction limitation multiplying factor and beam transmitting factor, presented laser beam parameter measurement procedure, evaluation methods and the corresponding calculation formula which were provided by ISO standard file.The paper provided array digital CCD technology, embedded technology combining special integrated circuit technology to realize the embedded laser beam quality analyzing system based on researches on beam quality evaluation theory. The paper did researches on embedded image processing technology, introduced applications of embedded image processing system, embedded Linux operation system and embedded image user interface, and mainly discussed the key technique for QT/Embedded programming. Finally the paper designed image processing platform for the embedded laser beam quality analyzing system on the premise of combining the above key techniques , which included building embedded cross compiling circumstance, transplanting boot loader program, pruning and transplanting Linux and so on. After analyzing the major factor affecting the laser spot image quality in the system, the paper laid special stress on how embedded processor run filter algorithm such as image middle value, grey scale shaking, average frame and so on to process the image information to decrease the measurement error.Development of system hardware included designing of optical attenuation, focusing, and reflecting optical system, development of accurate mechanic unit, controlling of step motor, image data sampling, storing and transmitting unit, image processing and display, etc. The paper solved the key technique such as Field Programmable Gate Array as cache in the image data sampling and transmitting, direct memory access and so on. After the system’s assembling, debugging and testing, it was shown that this system could measure the laser beam quality accurately and fastly, which gave the values of M~2 factor, beam waist diameter, beam waist position, divergence angle, two-dimension and three-dimension distribution of laser light intensity, spot shape and so on directly. The paper improved the system’s real time by means of using the embedded operation system technique, therefore, system designed by this paper can measure the laser beam quality fastly, which actually realized real time measurement.Above all, the paper did researches on Gauss beam’s transmitting, transforming property and property parameter when Gauss beam passes through thin lens by using the matrix method, especially discussed the evaluation and measurement for beam quality, adoptsed measurement suggestion established by international standard, built up a laser beam quality analyzing system which used digital CCD as detector, combined embedded processor and FPGA technique. Finally, applied the system to measure quality of He-Ne laser, gave the light intensity distribution, calculated the beam parameter by two order moment integral method, imitated the hyperbolic curve of laser beam transmitting to obtain the complete light intensity distribution information by using background subtract method to elimate noise, multi-frame average to remove trembling and Gauss imitation.System designed by the paper proposed an effective tool for laser beam quality detesting, provided theoretical reasoning and practical basis for the carry easily and small volume of measurement instrument. The embedded laser beam quality analyzing system was used to test some lasers’ quality, data showed that the system had advantages such as small random error, small repeatability error, strong recurring ability and so on, measurement precision of M~2 factor was less than 4% at beam waist position.更多还原