Efficient work measurement system of manufacturing cells using speech recognition and digital image processing technology

Work measurement methods previously proposed require considerable time and effort by time study analysts because they have to measure the required time through direct observations. In this study, however, we propose a method which efficiently measures the standard times without involving human analysts by using speech recognition and digital image processing techniques. First, we implement a prototype system which can acquire the status of manufacturing cells through a speech recognition system. Second, using image processing, we suggest a method which consists of two main steps: motion representation and cycle segmentation. In the motion representation step, we first detect the motion of any object distinct from its background by differencing two consecutive images separated by a constant time interval. The images thus obtained then pass through an edge detector filter. Finally, the mean values of coordinates of significant pixels of the edge image are obtained. Through these processes, the motions of the observed worker are represented by two time series of data of worker location in horizontal and vertical axes. In the cycle segmentation step, we extract the frames which have maximum or minimum coordinates in one cycle, store them in a stack, and calculate each cycle time using these frames. In this step we also consider methods for detecting work delays due to unexpected events such as an operator’s movement out of the work area, or interruptions. To conclude, the experimental results show that the proposed method is very cost-effective and useful for measuring time standards for various work environments.     

基于互相关理论的超声波气体流量测量电路系统

介绍一种基于互相关理论的超声波流量测量电路系统。该系统以数字信号处理器(DSP)为核心,通过采集上、下游流动信号并做互相关运算,计算出互相关函数峰值对应的渡越时间,间接测出流量。采用抛物线插值计算互相关函数峰值,减少测量误差。它对流场不敏感,测量精度高,在气体的测量实验中,取得了比较理想的效果。     

基于计算机视觉的电机换向片检测系统的研究

设计了一种新型的电机换向片自动检测系统,该系统通过CCD图像传感器采集电机换向片图像,在VC平台中嵌入Matlab,利用其Image Processing Toolbox对图像进行变换处理与特征识别,实现计算机视觉代替人类视觉驱使数控机械工作。实验表明该系统精度高、实时性强,具有一定的实用价值。     

基于机器视觉的抗生素残留量检测系统研究和开发

本文设计了一种结合机器视觉和各领域成熟技术的自动检测系统，以实现符合行业标准的四环素族抗生素残留量检测。通过CCD器件采集图像后，进行自适应差分滤波预处理，采用改进的四叉树交叉熵分割算法进行准确快速的分析，提出多分辨率的圆检测算法精确检测抑菌圈直径数据，最后对数据建模统计，得到分析结果。实验证明，设计并开发的检测系统具有精度高、重现性高、操作简单、客观性强、专业性强等显著优点，可推广到其他的抗生素检验领域。     

Magnet alignment on a common girder: Development of a length artefact for measurement accuracy improvement

The tolerances for the alignment of the magnets on the girders of the proposed particle accelerator of the Brazilian Synchrotron Light Laboratory (LNLS), Sirius, are as small as 40 μm for translations and 0.3 mrad for rotations. The functional axis of the magnets is measured by the vibrating wire technique, which employs conductive wires of diameters of approx. 0.1 mm. Since the alignment has to be performed targeting these magnetic axes, rather than their geometric centrelines, non-contact measuring sensors mounted on a coordinate measuring machine have been chosen to measure the relative deviations between magnets. To better the measurement accuracy for that specific measuring task, to allow interim checks on multiple coordinate measuring systems, and to provide effective traceability to the SI unit of length, a multipurpose geometrical artefact has been devised. The reasoning behind this development and the first measurement results are described in this paper.     

Scanning measurement of aspheres

The measurement of aspheres today is often done using computer generated holograms with interferometry. We show that this method holds some significant systematic errors caused by imperfect adjustment of the optical components. This gives rise to the question if a measurement is possible without utilization of computer generated holograms. Therefore we propose a new elliptical setup using a laser interferometer and a set of scanning mirrors. Our work shows that this setup is capable of form measurement for individual aspheres but still poses some adjustment challenges.     

基于机器视觉技术的疲劳裂纹自动检测实验系统

为解决现有传统的金属疲劳裂纹检测方法存在的精度不高、操作繁琐、抗干扰性差和不易实现自动记录等问题,将虚拟仪器和图像处理技术应用到金属疲劳裂纹检测系统中,进行了疲劳裂纹长度在线测量和疲劳扩展速率计算。通过系统的整体设计和原理介绍,提出了疲劳裂纹在线非接触式的机器视觉检测方案;并基于LabVIEW的实验平台,进行了疲劳裂纹扩展试验,通过使用NI的IMAQVision实现了图像处理功能。研究结果表明,由该方案建立的基于图像处理技术的裂纹检测系统在线测量得到的最大裂纹长度测量误差为0．148mm,且由拟合裂纹长度一时间曲线的导函数可得到裂纹扩展速率,是一种较理想的疲劳裂纹在线检测方法。     

A machine vision system for tool wear assessment

Automated tool condition monitoring is gaining considerable importance in the manufacturing industry. This can be attributed to the transformation of manufacturing systems from manually operated production machines to highly automated machining centres. Modern image processing techniques and machine vision systems can now enable direct tool wear measurement to be accomplished in-cycle. Such a system, characterized by its measurement flexibility, high spatial resolution and good accuracy, is presented here. The system consists of a fibre-optic light source to illuminate the tool and a CCD camera (used in conjunction with a high resolution video zoom microscope) to capture the reflected pattern. The extent of the flank wear land has been determined using both textural and gradient operators; a texture operator has been implemented in the final system.     

基于机器视觉的齿轮缺陷快速检测

结合齿轮缺陷自身的特点，论述了齿轮缺陷检测系统的构成、图像处理及检测流程，提出了一种基于机器视觉的齿轮缺陷快速检测方法。实例分析表明．该检测系统能够快速、准确地实现齿轮缺陷的检测，满足自动化生产的需要，可在实际生产中代替人工检测；     

Usability assessment of selected methods of optimization for some measurement task in coordinate measurement technique

This paper presents the comparison of selected methods of optimization on the example of some measurement task in coordinate measurement technique. The task consists in the computation of coordinates of the center and radius of a circle which approximates some set of measured points using least squares. The application of the least squares method follows an approach used in conventional analysis of an associated element in coordinate measurement technique. The coordinates of points are measured on a CNC machine tool equipped with a measuring probe.     

车床主轴回转精度测量系统的研制

车床作为制造业的基础设备,零件加工精度受到诸多因素制约,其中主轴回转误差是主要的影响因素之一.该车床主轴回转精度计算机测量系统由光电编码器、电涡流传感器、微机、变送器、数据采集卡及辅助工具构成.在测量车床主轴回转精度的同时,可获得与主轴角位置对应的径向跳动、端面跳动和角度摆动误差,使用数理统计法误差分离技术编制LabV...     

High accuracy profile measurement of quasi-conical mirror surfaces by laser autocollimation

A method is described for measuring the profile of a quasi-conical mirror surface along one of its axial generators. A laser beam is made to scan the surface and the variation in reflected beam angle is measured by autocollimation. Integrating the angle with respect to distance along the generator gives the profile height to within ±5 nm. The method has application to the metrology of X-ray microscope reflecting objectives     

面向大型工件现场测量的光笔式视觉测量系统

研制了一种面向大型工件现场测量的光笔式视觉测量系统,对其中的关键技术进行了深入研究。该系统主要由带有红外LED光点的光笔、1台CCD摄像机、靶点亮度控制器、一维标定尺以及安装有测量软件的计算机组成。在对LED点光源光强控制方式及成像系统工作原理进行分析的基础上,设计并实现了以多靶点亮度自适应控制技术和主动离焦模糊技术相结合的靶点光斑图像生成技术。该技术保证了在大跨度测量范围内均能获得高质量的靶点光斑图像,解决了对焦成像中摄像机视场范围与景深有限的问题;针对光笔标定问题,提出了一种简便易行的现场标定方法,此方法只需要若干个辅助靶点和2个以上间距已知的圆锥孔,就可以同时确定光笔上各靶点及光笔测头在光笔坐标系下的坐标。实验结果显示:该测量系统在2~10 m空间长度测量标准差不大于0.095 mm,能够满足中等精度的大型工件现场测量要求。     

基于液位测量系统的定时器的开发

本文基于液位测量系统设计开发了定时器,其中 IC555用于不稳定模式。使用数字存储振荡器(DSO)测量的定时器输出波形接通时间的脉冲宽度,即电容器充电时间(T C ),与同轴圆柱形电容换能器的电容成线形比例,且该电容随着液位的变化而线性变化。因此,我们获得了电容器充电时间与液位的线性关系,该设计的优点是输入-输出具有线性关系,尺寸小,便于携带,成本低,且不受环境温度影响,它还可用于测量各种工业中液体或固体的介电常数。     

采用机器视觉的汽车活塞最终质量自动检测系统

介绍一种基于机器视觉技术的活塞终检方法。采用具有独特的双光源光路的机器视觉系统获取活塞表面图像信息,以LabView软件为平台对数字图像信息进行处理和分析,实现了全部活塞终检项目的一次性检测。实际应用证明该系统稳定可靠,检测效率高,检测性能优于国外进口同类产品。     

Laser tracker performance quantification for the measurement of involute profile and helix measurements

Standard-conforming measurements for a large involute gear were performed with a manually operated laser tracker system and the corresponding task-specific measurement uncertainties were estimated. Especially, readers using laser trackers for inspecting large involute gears will get information of a taskspecific measurement performance for the first time, which significantly differs from the laser tracker machine specification. To ensure unambiguous and repeatable measurement results, user-friendly auxiliary tools are used, which allows the operator to probe the measurement points according to existing guidelines and standards. Measurements were taken on a robust and highly accurate large involute gear measurement standard of the Physikalisch-Technische Bundesanstalt (PTB) under laboratory conditions. The size of this gear measurement standard complies with those gears used in wind power plants. The external gear materializes a left and a right hand gear as well as a spur gear. The obtained results of profile, helix and surface measurements are presented. These research activities were carried out at the PTB in the department of coordinate metrology.     

基于光栅投射的光学三维测量仪的研制

利用商用数字LCD投影仪和数字CCD摄像机构成一套基于光栅投射的光学三维测量系统,介绍系统的测量原理、硬件结构和软件系统,最后给出该系统的一些测量结果。     

基于虚拟仪器的轴瓦高出度测试系统的开发

针对目前国内轴瓦高出度测试中存在的问题,提出了一种基于虚拟仪器的6点测量模型法的轴瓦高出度测试方法,给出测试系统的框图及相关功能,经实验验证,该系统能够满足测试的效率和精度要求。     

可重构数字式机电测控试验平台的研制

提出采用可重构制造思想来研制数字式机电测控试验平台 ,介绍了试验平台的系统结构、功能和基本原理 ,按照可重构制造原理对试验平台的软、硬件模块进行了划分 ,对可重构制造系统理论在试验平台中的应用作了分析和探讨。