衍射法X射线激光分束光栅平行度测量系统(英文)

介绍了软X射线光栅分束镜Mach-Zehnder干涉等离子体诊断系统调整用双频光栅线条平行度的衍射法测量系统.该系统主要由激光器,准直镜,待测光栅,精密转台(含角度测量仪),直线工作台,光栅调节架和探测器组成.分析了系统中各种误差对测量精度的影响其中包括距离测量误差、波长误差、光栅准直误差即光栅刻线与入射光和反射光组成的平面不垂直、光栅转动过程的误差、光栅表面面型误差、探测器误差,经计算得到系统的绝对误差为minute.计算表明,该系统的测量精度满足软X射线Mach-Zehnder干涉系统对双频调整光栅的性能要求.     

斜入射衍射光栅对波长测量的影响

为了研究斜入射衍射光栅对波长测量的影响,采用了平行光斜入射衍射光栅,得出了平行光斜入射角越大,其波长误差也就越大,并推导出了入射角与波长误差的经验公式,其研究结果将有利于对测量波长的矫正。     

常角法测量经纬仪测角标准偏差的测量结果不确定度分析

用多支平行光管组成常角 ,进行全圆检定对经纬仪进行测角标准偏差的测量 ,对测量结果进行不确定度分析。     

非接触表面轮廓测量仪的研制

本文研究了一种始终使得光学测头处于焦点位置,以正交衍射光栅干涉位移传感器为位移测量系统,以压电陶瓷作为驱动部件的非接触表面轮廓测量仪,用于实现对零件表面粗糙度,波度,表面形状误差和尺寸的综合测量。论文着重介绍了该仪器的整体结构,测量原理及衍射光栅干涉计量系统的工作原理。     

常角法测量经纬仪测角标准偏差的测量结果不确定度

用多支平行光管组成常角,进行全圆检定对经纬仪进行测角标准偏差的测量,对测量结果进行不确定度分析.     

常角法测量经纬仪测角标准偏差的测量结果不确定度分析

用多支平行光管组成常角，进行全圆检定对经纬仪进行测角标准偏差的测量，对测量结果进行不确定度分析。     

在一米测长机上测定长光栅数显仪的不确定度

长光栅数显仪是一种应用于各种数控、数显机床及长度计量仪器的新型线位移测量器件。它的不确定度直接影响着加工精度或测量精度。目前人们常用激光测长装置来测定长光栅数显仪的不确定度。在没有激光测长装置的精况下,可在一米测长机上加上自制的专用检具,     

光栅分振幅光偏振测量系统的研制

使用一个既能产生反射光衍射又能产生透射光衍射的特殊金属光栅作为分光器,研制一种新颖的高速光波偏振态测量系统。它没有使用转动光学部件或调制器,而是将金属光栅产生的四条1级衍射光的光强线性地转换为电信号,通过定标方法得到系统的非奇异的仪器矩阵,然后通过线性运算得到入射光的待测Stokes矢量。该系统结构紧凑、安装方便,可用作实时偏振测量术和椭偏测量术中的偏振态探测器。     

激光线位移传感器基本误差测得值的不确定度评定

本文介绍了用光栅式指示表检定仪测量输出为电流信号的线位移传感器的不确定度评定方法,为以后测量输出为电信号的线位移传感器的不确定度评定提供参考.     

公法线千分尺的调修

公法线千分尺在使用中,由于测量面的磨损等原因,造成两测量面不平行,使测量值与工件实际值不相符。为此需要对两测量面进行修理。我们采用下述方法进行修复,现以0～25mm公法线千分尺为例: 首先对两测量面进行平行性误差测量,把固定测砧平面作为标准面(见图1)。再把每次误差记录下来,并进行分析,一般有三种情况: 第一种情况如图2所示:按图分析,因四个测量面的误差,大致都在同一位置上,可以认定是固定测砧平面对轴心线不垂直,而活动测量砧平面是垂直轴心线的,只要修研固定测砧平面+8部位,待研出后再测量直至修复。     

Simultaneous multiplane imaging with a distorted diffraction grating

We describe a simple technique for simultaneously imaging multiple layers within an object field onto a single camera. The approach uses a binary diffraction grating in which the lines are distorted such that a different level of defocus is associated with each diffraction order. The design of the gratings is discussed, and their ability to image multiple object planes is validated experimentally. Extension of the technique for spherical-aberration correction is described, and it is shown how the gratings can be used as part of a wave-front-sensing system.     

二自由度云台的机器视觉控制

本文建立了基于机器视觉反馈的云台控制模型,并通过相邻帧间的目标位置预测来简化搜索算法,实现快速高效的视觉云台对运动目标的连续跟踪.在制定系统空间转角输入量的控制策略中,简化了控制模型并对产生的偏差量进行了分析.结果表明,简化后的控制算法能够实现快速反馈和像面调整,在25帧/秒时实现对运动目标稳健跟踪,且跟踪精度高于传统算法;在目标速度2 m/s、相机60帧/秒时,改进算法实现了对运动目标的连续跟踪.同时提出了立体视觉系统模型及其在云台控制中的应用,通过像面坐标获取空间位置信息以规避目标跟丢现象.     

利用鱼眼照片恢复景物的深度信息

通过照片获取深度信息的技术已经研究多年，也产生了各种算法，但这些算法或者需要一张以上的照片来计算，或者运算量比较大。此外，它们的共同点是：各种方法采用的照片是用普通镜头拍摄的。笔者给出一种新的方法：利用一张鱼眼镜头照片和少量的辅助手段来获取深度信息。建立了一种简便而又准确的辅助手段，从而可以构造景物的三维框架，最终可以实现在景物内的任意位置向任意方向进行虚拟浏览。     

红外测量系统动态测角误差分析

介绍了一种光电测量设备红外测量系统动态测角误差检测方法，该方法是通过将红外系统测量数据与主摄影系统测量数据相比对，并对红外系统与主摄影系统平行度进行了定点修正，且与主摄影系统动态测角误差合成后实现的，叙述了检测设备的组成、检测方法、数据处理过程及测量结果，这一检测方法适用于具有摄影系统的光电测量设备的红外系统和电视系统等其它分系统动态测角误差的检测。     

Profile measurement taken with liquid-crystal gratings

Profile measurement taken with liquid-crystal gratings and a phase-shifting technique is proposed, and its effectiveness is verified by experiment. The surface profile is obtained by measurement of the phase distributions of the sinusoidal gratings deformed by an object's surface. The liquid-crystal grating gives an accurate phase shift, an arbitrary projection pitch, and a constant surface brightness compared with conventional gratings such as a laser interference fringe grating and a Ronchi grating. Therefore a flexible measuring system may be developed with it. Two gratings with different pitches are used to measure an object with large steps. A two-color projection system can be used to produce such gratings simultaneously. Locally varying reflectivity on a surface can also be compensated by adjustment of the color component of the projected grating with a liquid-crystal grating. Thus the contrast in the projected grating can be made uniform, and a good profile measurement can be accomplished.     

Performance Analysis and Evaluation of Geometric Parameters in Stereo Deflectometry

This paper presents a novel geometric parameters analysis to improve the measurement accuracy of stereo deflectometry. Stereo deflectometry can be used to obtain form information for freeform specular surfaces. A measurement system based on stereo deflectometry typically consists of a fringe-displaying screen, a main camera, and a reference camera. The arrangement of the components of a stereo deflectometry system is important for achieving high-accuracy measurements. In this paper, four geometric parameters of a stereo deflectometry system are analyzed and evaluated: the distance between the main camera and the measured object surface, the angle between the main camera ray and the surface normal, the distance between the fringe-displaying screen and the object, and the angle between the main camera and the reference camera. The influence of the geometric parameters on the measurement accuracy is evaluated. Experiments are performed using simulated and experimental data. The experimental results confirm the impact of these parameters on the measurement accuracy. A measurement system based on the proposed analysis has been set up to measure a stock concave mirror. Through a comparison of the given surface parameters of the concave mirror, a global measurement accuracy of 154.2 nm was achieved.     

基于车道线斜率的车道偏离检测

针对结构化道路上运动车辆的车道偏离检测问题,采用单目视觉作为感知手段,分别从针孔模型下摄像机成像的空间几何关系和图像中车道线消失点的位置特点两个方面出发,推导出车辆直行情况下车道偏离率与两侧车道线斜率比之间的简单函数关系,该函数与摄像机内外参数无关。同时完成了在摄像机不同方向角下的车道偏离率测量试验,结果表明由于行车方向瞬时变化引起的摄像机方向角微小改变对车道偏离检测的影响可以忽略。道路现场试验结果表明,上述视觉测量方法得到的车道偏离率与手工实测结果相比,其相对误差小于5%。基于车道线斜率的单目视觉检测方法避开了繁琐的摄像机参数标定过程,达到了较高的车道偏离检测精度。     

莫尔偏折技术用于测量镜片屈光度的研究

本文从莫尔偏折技术的基本原理出发,结合镜片屈光度的概念,分别从泰伯效应与光栅遮光阴影原理相结合以及菲涅耳-基尔霍夫理论的角度推导了变形后的莫尔条纹倾角与被测镜片屈光度的关系.两种方法推算结果是一致的,即:镜片的屈光度与透过镜片后产生的莫尔条纹的倾角的正切成正比.对影响镜片屈光度测量误差的几个参量进行了讨论,理论分析表明,选用合适的光栅周期,设定合理的两光栅间夹角,莫尔偏折技术用于测量低屈光度及中高屈光度的镜片具有很高的测量精度.最后给出了测量单光镜片,非球面镜片和渐进多焦点镜片的莫尔条纹图,并进行了分析讨论.     

Tilt sensitivity of the two-grating interferometer

Fringe formation in the two-grating interferometer is analyzed in the presence of a small parallelism error between the diffraction gratings assumed in the direction of grating shear. Our analysis shows that with partially coherent illumination, fringe contrast in the interference plane is reduced in the presence of nonzero grating tilt with the effect proportional to the grating tilt angle and the grating spatial frequencies. Our analysis also shows that for a given angle between the gratings there is an angle between the final grating and the interference plane that optimizes fringe contrast across the field.