激光调阻机光学系统设计

激光调阻机是用于片式电阻阻值微调的一种关键设备,由光学系统、阻值实时测量系统、精密机械系统、自动上下料系统、计算机控制系统等构成。调阻精度可达1%。在激光调阻机中,光学系统是非常重要的组成部分,它影响着激光光束质量、调阻的速度和精度。本位介绍了一种光学系统设计方案,论述了各个组成部分的构成和设计要求。通过实际的工作验证,此设计方案合理、实用。     

激光淬火加工质量视觉检测系统研究

针对金属表面激光离散淬火质量检测的需求,基于OpenCV设计了一种淬火斑尺寸测量和表面纹理检测的视觉检测系统。深入研究了相关图像处理算法,对Canny边缘检测算法进行了改进,实现了图像轮廓的选择性提取,得到了激光淬火斑连通域的几何尺寸,采用灰度共生矩阵计算淬火斑纹理信息。并根据三种不同能量输入背景下进行激光离散淬火产生的淬火斑,提出了一种双阈值判定方法来实现其质量检测,平均检测用时为10.1ms,检测准确率在92.5%以上。     

面向网络攻防演练的操作系统仿真模型研究与实现

针对目前网络攻防演练中对主机行为的表现粒度不足的问题,通过分析操作系统概念以及性质,给出了一种用于网络攻防演练的操作系统仿真模型。该模型反映了操作系统的安全属性。还给出了该仿真系统的体系结构,使得仿真系统具有一定的扩展性。     

Design and development of automatic visual inspection system for PCB manufacturing

Inspection of solder joints has been a critical process in the electronic manufacturing industry to reduce manufacturing cost, improve yield, and ensure product quality and reliability. This paper proposes two inspection modules for an automatic solder joint classification system. The “front-end” inspection system includes illumination normalisation, localisation and segmentation. The “back-end” inspection involves the classification of solder joints using the Log-Gabor filter and classifier fusion. Five different levels of solder quality with respect to the amount of solder paste have been defined. The Log-Gabor filter has been demonstrated to achieve high recognition rates and is resistant to misalignment. This proposed system does not need any special illumination system, and the images are acquired by an ordinary digital camera. This system could contribute to the development of automated non-contact, non-destructive and low cost solder joint quality inspection systems.     

基于辩纤传感器与激光测距原理的物位检测系统设计

设计了一种对固体火箭发动机推进剂装药高度进行物位测量、显示以及预警的检测系统.系统采用了基于光纤传感器与激光测距原理的非接触式物位检测方案,使用光纤传导激光,使带电设备远离检测现场,在现场完全不带电的环境下,完成高精度物位检测;通过系统主控单元控制多个传感器可实现多点同步检测,从而能够在装药表面不是绝对平面的情况下得到...     

Measurement error analysis and accuracy enhancement of 2D vision system for robotic drilling

Robotic drilling for aircraft structures demands higher accuracy on industrial robots than their traditional applications. Positioning error measurement and compensation based on 2D vision system is a cost-effective way to improve the positioning accuracy in robotic drilling. In this paper, we first discuss the principle of error measurement and compensation with a 2D vision system for robotic drilling and the determination of tool center point of the vision system so that the Abbe errors are eliminated in the measurement process. Measurement errors due to nonideal measurement conditions, i.e. nonperpendicularity of the camera optical axis to the workpiece surface and incorrect object distance, are mathematically modeled and experimentally verified. A method utilizing four laser displacement sensors is proposed to ensure perpendicularity of the camera optical axis to the workpiece surface and correct object distance in the measurement process, and hence to achieve high accuracy in 2D vision-based measurement. Experiments performed on a robotic drilling system show that the 2D vision system can achieve an accuracy of approximately 0.1 mm with the proposed method.     

CATALOG: a system for detection and rendering of internal log defects using computer tomography

This paper describes the design and implementation of a machine vision system CATALOG for detection and classification of some important internal defects in hardwood logs via analysis of computer axial tomography (CT or CAT) images. The defect identification and classification in CATALOG consists of two phases. The first phase comprises of the segmentation of a single CT image slice, which results in the extraction of 2D defect-like regions from the CT image slice. The second phase comprises of the correlation of the 2D defect-like regions across CT image slices in order to establish 3D support. The segmentation algorithm for a single CT image is a complex form of multiple-value thresholding that exploits both, the prior knowledge of the wood structure within the log and the gray-level characteristics of the image. The algorithm for extraction of 2D defect-like regions in a single CT image first locates the pith of the log cross section, groups the pixels in the segmented image on the basis of their connectivity and classifies each 2D region as either a defect-like region or a defect-free region using shape, orientation and morphological features. Each 2D defect-like region is classified as a defect or non-defect via correlation across corresponding 2D defect-like regions in neighboring CT image slices. The 2D defect-like regions with adequate 3D support are labeled as true defects. The current version of CATALOG is capable of 3D reconstruction and rendering of the log and its internal defects from the individual CT image slices. CATALOG is also capable of simulation and rendering of key machining operations such as sawing and veneering on the 3D reconstructions of the logs. The current version of CATALOG is intended as a decision aid for sawyers and machinists in lumber mills and also as an interactive training tool for novice sawyers and machinists. Received: 1 August 1997 / Accepted: 25 August 1999     

激光质谱系统中激光波长高实时集中控制研究与应用

随着激光共振电离质谱系统的迅速发展,更准确地研究激光波长与电离质谱信号的关系,实现激光波长与电离质谱信号的自动对比,开展了激光波长高实时集中控制的研究。采用数据库技术、多线程技术和RS485通讯技术等完成了激光波长的高实时控制的研制工作。该系统实现了对激光波长的闭环和各种方式的扫描控制及运行状态的实时监测功能,能够以外触发方式与质谱系统进行同步,满足了激光质谱系统对波长的大范围、小范围及精细扫描的需求,实现了波长单步扫描数据响应时间小于250ms。     

用于冷原子干涉仪激光时序控制的DDS跳频系统设计与实现

为了满足冷原子干涉实验对时序控制的需求,设计并实现了一个基于LABVIEW软件的激光时序控制DDS系统,其工作过程为通过设计的LABVIEW上位机软件输入需要产生的频率和频率间隔时间,ARM芯片根据LABVIEW软件发送来的控制信息实现对射频信号芯片的控制,CPLD芯片用来控制射频信号之间的时间间隔,最后DDS芯片产生与控制信息相对应的射频信号。与目前同类装置相比,系统实现了跳频时间和频率更加精确和工作稳定性更好。经过系统的调试分析以及性能测试,DDS跳频系统能够满足原子干涉仪激光时序控制需求。通过测试DDS装置,DDS装置能够输出准确输出射频频率值,并且射频频率时间间隔能精确到微秒。DDS装置可以有效控制冷原子干涉仪的激光时序,在探询时间为120毫秒且重复率为2.2赫兹的情况下,冷原子重力仪的重力测量灵敏度达到 。     

A cost-effective and automatic surface defect inspection system for hot-rolled flat steel

Defective steel brings economic and commercial reputation losses to the hot-strip manufacturers, and one of the main difficulties in using machine-vision-based technique for steel surface inspection is time taken to process the massive images suffering from uneven illumination. This paper develops a modular and cost-effective AOI system for hot-rolled flat steel in real time. Firstly, a detailed system topology is constructed according to the design goals covering the vast majority of steel mills, lighting setup and typical defect patterns are presented as well. Secondly, the image enhancement method is designed to overcome the uneven-lighting, over- or under-exposure. Thirdly, the defect detection algorithm is developed based on variance, entropy and average gradient derived from non-overlapping 32×32 pixel blocks of steel surface images. Fourthly, the proposed algorithms are implemented on FPGA in parallel to improve the inspection speed. Finally, 18,071 contiguous images (4096×1024 pixel) acquired from 7 defective steel rolls have been inspected by the realized AOI system to evaluate the performance. The experimental results show that the proposed method is speedy and effective enough for real applications in the hot-rolled steel manufacturing, with 92.11% average accuracy while 5.54% false-negative rate.