指针式仪表自动检测系统中的图像处理技术

摘要设计了一套自动寻找图像(仪表刻线盘)中心的图像处理系统,减少了人工辅助操作,能够自动对仪表表盘或刻线盘的中心进行定位,提高了自动化程度和检测效率,有利于各类指针式仪表自动检测系统的推广和应用.     

一种鲁棒的线纹尺图像刻线提取算法研究

为解决光照不均匀、锈斑、污损等因素造成的钢卷尺图像检测识别不准确问题,提出了一种基于Cabor变换的钢刻线提取方法。通过Cabor变换,使特征方向与特定频率的线条结构被过滤呈现出来,基于这些线条结构计算图像中的线纹尺待检刻线位置,之后通过RANSAC算法拟合刻线的双边缘,从而准确获得刻线中心位置。经实验证明,该算法可以在刻线质量较差的情况下,鲁棒地识别破损和有锈斑的刻线,有效地提高检测准确度和整个测量系统的鲁棒性,具有技术参考价值。     

影像式钢卷尺标准装置关键技术研究与试验

图像采集及处理是影像式钢卷尺全自动标准装置稳定性、可靠性的关键。该研究对采集的图像进行降噪、阈值分割、图像中刻线边缘检测等技术处理;同时为适应不同生产厂家和不同类型的钢卷尺所具有的刻线特征,设计了最长刻线识别、最靠近起始刻线识别、最高刻线识别三种定位算法;然后,完成样机的试制,并进行相机像素标定及工作钢卷尺示值误差标定;最后选择20 m量油尺、5 m弧面式工作钢卷尺、30 m摇架式工作钢卷尺为试验对象,分别进行重复性试验,得出各钢卷尺示值误差在允许范围之内、重复性试验结果均满足不确定度评定要求。该研究结果为钢卷尺全自动检定、图像处理及边缘检测等技术提供借鉴与参考。     

印刷品缺陷在线检测算法的研究

介绍了基于数字图像处理的印刷品缺陷在线检测系统的原理和工作流程.提出了一种改进的图像配准算法对标准模板图像和待测图像进行匹配.实验结果表明,该算法计算速度快、检测精度高,满足了系统设计的要求.     

数字图像处理在距离测量中的应用

为了克服接触式测量中的一些弊端,如测量时加在物体上的物理效应、测量环境的高要求、人为误差较大等,结合了现代数字图像处理技术和视觉测量方法,采用了非接触式测量方法进行距离测量.建立了图像采集系统,运用Labwindows/CVI软件设计的Sobel算子对采集到的图像进行边缘检测,得到两边缘线之间的像素差值,并代入距离计算公式求得距离.结果表明,该测量方法所得结果与实际值符合,证实了基于数字图像处理的距离测量方法的准确性.     

仿真系统实现中样本提取算法的研究

如何提取样本图像是当前仿真系统实现中的主要难点而提取样本图像在数字图像处理中属于边缘检测技术.目前国内外边缘检测的方法有很多种主要研究基于Canny边缘检测的样本提取算法.     

2m比长仪纳米级高精度刻线自动瞄准系统

阐述了2m比长仪刻线瞄准系统的组成,对其光电显微刻线成像的原理及刻线图像信号进行了分析,根据其刻线信号的特点,研究了其高精度的刻线信号自动处理系统,该系统基于FPGA现场可编程电路技术,实现刻线信号的自动门控触发、自动滤除虚假刻线信号,配合计算机信号自动处理软件可以实现刻线测量的高精度自动瞄准.最后对2m比长仪的瞄准精度进行了测试实验,实验结果表明,测量金属标准线纹尺时,2m比长仪单次测量刻线瞄准精度优于10nm(1σ).     

基于光切法和数字图像处理技术的槽深测量

为测量不锈钢管外表面窄浅刻槽的深度,提出了一种基于光切法采用摄像头获得不锈钢管表面和刻槽底部的图像,运用数字图像处理技术对这些图像进行处理的刻槽深度测量方法.介绍了光切法测槽深的原理以及数字图像处理的步骤,应用表明,该方法有较高的测量准确度.     

宽幅胶片弊病在线检测系统的研制

研制了一种基于CCD成像和数字图像处理技术的宽幅胶片弊病在线检测系统.在红外光源提供均匀照明的条件下,采用两台高分辨率线阵CCD摄像机对运转速度为90 m/min、宽幅为1300 mm的胶片实时成像,利用简化了的平滑去噪和边缘检测算法进行处理,并通过双阈值判据及时发现弊病,保存弊病位置信息和弊病图像.系统检测能力为横向80 μm,纵向500 μm,能够检测出各种典型的弊病.     

光笔式视觉坐标测量中基于曲线拟合的图像处理方法

提出了光笔式视觉坐标测量中被测特征点像面坐标的提取方法。依据数字图像处理理论并结合测量系统中被测特征点的成像特点,给出了图像预处理过程及实际处理结果;采用基于灰度质心法的径向截面扫描法对图像边缘进行亚像素级检测;应用平面内任意位置椭圆的最小二乘曲线拟合法对椭圆形光斑中心的像面坐标进行了提取,实验结果表明该方法的提取精度为0.1个像素。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。