基于机器视觉的前照灯仪校准器检定装置

目前对汽车前照灯仪校准器的人工检定方法存在着检定效率低、测量不确定度大的缺点,而利用机器视觉技术改造后的检定装置则存在着CCD芯片本身无法进行量值溯源的原理缺陷.建立了一套结合机器视觉技术与传统检定方法的检定装置,根据机器视觉分析得到校准器光型特征,利用转台测量光轴角参数及照度计测量发光强度参数,可以实现高准确度、高效率的检定.实验结果表明,该装置的性能完全满足检定前照灯仪校准器的要求.     

二维自跟踪视觉准直测量系统

为了提高自准直仪的测量精度和降低人眼瞄准的劳动强度和主观误差,提出一种基于机器视觉的二维自跟踪视觉准直测量系统。该系统由光学准直仪、CCD和图像采集卡等组成。以面阵CCD代替人眼对自准直仪的十字分划板图像进行瞄准;采用图像不变矩自动搜索算法和hough变换、亚像素细分等方法实现对小角度的自动精确测量。实验结果表明,该系统测量范围达到±15',最小分辨力优于0.1″,与MJS双频激光测角系统比对误差在0.6″以内,测量精度高于MJS,而且操作方便,易于推广。     

双目视觉系统测量精度分析

针对双目视觉系统测量精度的问题,本文提出并建立了双目视觉系统误差分析模型,分析了摄像机标定精度、镜头参数及系统结构参数对系统测量精度的影响,并结合实验证明了理论的正确性。实验表明,在标定板均匀分布于具有较大深度范围系统的整个可视区域时,增加标定图像数目能有效提高系统精度;在保证系统有效视场的前提下,增大基线距能有效的提高系统测量精度;相机光轴与基线夹角在[55o~70o]取值时,系统测量精度较高。     

快速测量类圆柱体工件端面垂直度

为解决传统的端面垂直度测量方法存在操作繁琐,测量速度慢,不适用于工程实际测量的问题,该文提出一种新的测量系统。该系统利用伺服电机带动工件平稳快速地通过测量区域完成测量,测量区域由一对高精度2D线激光传感器组成。实验结果表明:在60 s内完成10块工件的20个端面垂直度的测量,测量速度可提高10倍,测量精度为±3.86μm,标准差为1.04μm,测量精度优于传统测量方法。该系统具有快速、稳定、无损测量、操作简便、精度高等特点,符合端面对轴线垂直度的定义,且满足用户需求。     

光学机械式仪器有关垂直度检测和调修调整方法的研究

光学机械式仪器有关垂直度的要求,大体可分为以下几种类别：纵、横向滑板移动方向的垂直度;臂架移动方向与工作台面的垂直度;照明光轴与工作台面的垂直度;测量轴线与工作台面的垂直度;测帽工作面与测量轴线的垂直度等。     

基于近场声全息的高频换能器阵列声场测量方法

在二维平面声压构建技术理论基础上,结合空间傅里叶变换的近场声全息技术,提出一种高测量效率的声场测量方法。以由4个压电元件所构成的矩形活塞换能器阵列为测量对象,进行声场仿真和实验测量,验证该测量方法的测量精度与效率。结果表明,该方法相比面扫描法测量效率提高了560倍,相比积分法计算速度提高两倍,可有效应用于高频换能器阵列的声场测量。     

形状尺寸自动检测系统的设计

综合运用机器视觉技术和数控技术设计了一套能实现多种形状尺寸自动检测的系统。该系统使用步进电机驱动二维数控平台,采用CCD摄像头和光栅分段采集被测零件的轮廓图像和坐标,运用轮廓自动跟踪算法实现零件完整轮廓坐标数据的自动获取,利用形状尺寸检测软件实现零件直线度、圆度、平行度、垂直度等的检测。实验结果表明所设计的形状尺寸自动检测系统自动化程度较高,检测精度可达微米级。     

面结构光的货车侧面防护装置安装尺寸的测量

提出一种基于面结构光的货车侧面防护装置尺寸测量方法.即采用激光三角法原理,利用投影装置产生条纹状结构光,投射到货车侧面,结构光信息被视觉装置采集后由计算机处理,计算机通过结构光的条纹信息,实现货车侧面防护装置及车轮的空间三维信息反演,从而实现货车侧面防护装置尺寸测量.该方法避免了在普通机器视觉方法货车侧面防护装置检测中,由于车轮和防护装置与视觉装置的距离不同带来的测量误差.在系统设计的基础上,搭建了实验平台,进行了实验研究.由实验结果可知,采用本方法的货车侧面防护装置尺寸测量误差小于3mm,而原有视觉方法测量精度为10mm,可见本方法的测量精度远高于原有方法.     

三轴转台轴线垂直度的测试方法

为了测量中环轴、内环轴不能全回转的三轴转台回转轴线的垂直度误差,设计了利用自准直仪和平面反射镜将有限回转轴系轴线引出的方法。根据自准直仪读数与平面反射镜对回转轴线的垂直度误差、自准直仪的光轴与回转轴线的平行度误差之间的关系,利用最小二乘法引出外环轴处于不同位置时的中环轴轴线、内环轴轴线,实现了三轴转台轴线垂直度的测量。     

基于机器视觉的自动扶梯梯级测速方法

针对自动扶梯运行速度的检测,提出一种基于机器视觉的自动扶梯梯级测速方法。首先,对机器视觉系统采集得到的梯级运行图像进行一系列的预处理,通过设置阈值实现目标颜色的识别;然后,采用直线扫描法对颜色提取后的不连通区域进行填充,对得到的二值图像进行边缘检测与轮廓识别,返回轮廓面积最大的图像;最后,提取每张图像中黄色区域右边界直线起始端点的横坐标,通过差分法计算得到梯级的速度。结果表明,该方法实现了非接触测量并且能够得到较为准确的检测结果。     

同轴度测量方法综述

阐述了机械结构间同轴度、光轴间同轴度、光轴与机械轴间同轴度的定义,介绍了引伸计同轴度 测量方法、应变计同轴度测量方法、百分表同轴度测量方法、三坐标测量机同轴度测量方法、激光对中仪法等 机械结构间同轴度测量方法的原理和优缺点;分析了干涉比较测量法、反射式定心测量法、透射直接测量法等 光轴间同轴度测量方法的特点;介绍了基于图像处理和机器视觉技术的光轴与机械轴之间同轴度测量方法的原 理及应用。指出机械结构间同轴度的测量方法较为传统,存在测量效率低、需要人为判断等缺点;同轴度测量 技术将向高精度、自动化、非接触的方向发展。     

双目立体视觉的远距离运动物体运行姿态研究

提出了一种采用双目立体视觉测量技术来获得炮弹运行姿态的新方法.首先利用加权平均的方法求炮弹的质心,然后利用炮弹表面点到弹轴的距离相等的原理,用最小二乘拟合法推导出弹轴方程,得到弹轴矢量,最后通过建立弹轴矢量与姿态角之间的数学关系得到炮弹运行时的姿态角.仿真实验结果表明,该测量方法具有较高的精度,能满足远距离运动物体运动参数的测量要求.     

Machine vision assisted characterization of machined surfaces

This paper demonstrates the feasibility of using an inexpensive machine vision system to compute non-contact, optical parameters for the characterization of surface roughness of machined surfaces. Two parameters were selected for online analysis, where surface roughness is measured during the rotation of a specimen on a lathe. The sensitivity of the vision-based optical parameters to differences in surface roughness, ambient light and spindle speed of a lathe during measurement was evaluated. Statistical analysis of data collected through experimentation revealed that the vision parameters can discriminate different surface roughness heights and are insensitive to changes in ambient lighting and speed of rotation during measurement. The results of the experimental analysis were used to conclude the feasibility of using machine vision for the evaluation of surfaces.     

精仪工作台定量调整的原理及方法

论述了可调结构仪器工作台的结构、调整原理和调整方法,并以三点支撑结构、锥面支撑结构仪器工作台表面与测量轴线垂直度的调整为例,具体地阐述了调整方法和步骤。     

Simultaneous measurement of the velocity and the displacement of the moving rough surface by a laser Doppler velocimeter

A formula that can analyze the laser Doppler velocimeter spectrum was derived. The formula showed good agreement with computational experimental results. The use of a Fourier transform lens as detection optics was proposed and was found to be independent of the displacement of the object along the direction parallel to the optical axis. An experimental method was also proposed that can make the simultaneous measurement of velocity and displacement possible simply by adding a second detector. By using two detectors, not only can displacement of the surface be measured, but also the results of the speed measurement can be compensated for.     

基于MCNP的X光机模拟及足跟效应修正

为修正X射线管的足跟效应,根据常用的X射线管参数,基于MCNP建立了X光机仿真模型,模仿光机成像系统增感屏,建立了169个像素的探测器阵列,并利用该阵列探究了X射线管的足跟效应现象,采用多项式拟合分段修正的方法设计了足跟效应过滤片HEF,对足跟效应照度过高的区域进行匀整修正。通过平面过滤片与HEF的通量分布对比,发现HEF成功地将阴阳极轴线方向-12°至19°的范围修正到无过滤片时强度的60%,该区域通量的最大相对误差小于3%,实现较大匀整面积。通过模拟成像对比分析发现,经过HEF修正后的X光机,大大提高了物体分辨的能力。所提出的对特定X光管参数和成像阵列面足跟效应的修正方法具有一定的实用性与可推广性,对X光机的设计和使用具有一定的参考价值。     

基于颜色分割的印版网点面积率测量方法

基于机器视觉的印版质量检测角度,提出了一种基于颜色分割的印版图像网点面积率测量方法。首先,通过图像采集设备获取印版网点的显微图像,对采集的印版网点显微图像进行颜色空间转换,利用饱和度信息对变换后的图像进行粗分割;而后依据图像颜色色相信息对其进行精确分割,经过形态学去噪处理后,对分割后的印版显微图像进行像素统计,并计算网点面积率。实验结果表明,基于颜色分割的网点面积率测量方法的测量精度较高,版材适用性较好。     

Measurement based on fringe reflection for testing aspheric optical axis precisely and flexibly

A method based on fringe reflection is proposed to measure the optical axis of an aspheric mirror precisely and flexibly. In the measurement, a screen displaying a fringe pattern is moved along its normal direction, and a camera is located beside and observes the fringe pattern reflected via a tested surface. This method can test the optical axis of an aspheric mirror quantitatively before measuring the absolute height of the tested surface. And it can be combined with some presented methods that need to fit the aspheric mirror according to the optical axis to measure the surface. To validate the ability of this method, it is combined with one of the presented methods to measure absolute height of an aspheric mirror precisely and flexibly. Computer simulations and preliminary experiment validate the feasibility of this method.     

Study on the method of precision adjustment of star sensor

Star sensors are indispensable spatial measurement sensors for high-resolution earth observation and astronomical observations, and the demand for high measurement accuracy of satellite sensors continues to increase; thus, the star sensor optical machine adjustment error cannot be ignored. The commonly used installation error correction method cannot solely meet the precision analysis requirements. In this paper, the relationship between the optical machine installation and the star sensor measurement error is analyzed, and several common adjustment error correction methods are compared. An adjustment method for optical machines is proposed to meet the requirements of very high precision star sensors. The assembly precision requirements of the investigated very high precision star sensor are analyzed considering the whole machine, and then the optical components are controlled through optical precision adjustments to satisfy the precision requirements. Finally, through the complete machine calibration, the star sensor precision adjustment for an optical machine structure is verified. This method meets the requirements of very high precision sensors and is suitable for the precision adjustment of optical machine structures, which is of practical significance to improve the precision of star sensors.