A displacement measurement system based on optical triangulation method

A new displacement measurement system is described in this paper according to the basic principles of traditional lasertriangulation method. The range of the traditional measuring method is enlarged by measuring in sections. Three independent CCDs, which are distributed uniformly along the optical axis, are used to achieve subsection measurement. The planemirror is regarded as a virtual detector. When imaging beam is reflected by the plane mirror, the beam is imaged on theCC D. The designed system is equivalent to add a CCD. The feasibility of the displacement measurement system is verifiedby the experiment.     

A new method for measuring laser beam straightness error based on common-path compensation

A novel method for laser beam straightness error measurements based on common-path compensation is proposed. The basic principle of the method is described and the math-model is established. Furthermore, the influence of laser beam drift on straightness error measurements is analyzed. The experimental results show that the measurement accuracy can be greatly improved by using the common-path compensation for laser beam drift.     

A Novel Method to Simultaneously Measure the Straightness

A precise two--degree--of--freedom measuring system (2DMS) is developed based on single--mode optical fiber, LD, cube corner retroreflector and four--quadrant photodetector (4-Q), and the simultaneous on--line measurement of lateral and vertical direction straightness errors of the linear stage is carried out. The moving part is wireless, which eliminates any errors introduced by pushing and pulling the wires. The sensitivity of the straightness error measurement can be improved by a factor of 2 with the cube corner retroreflector. This fiber- based optically aligned beam is used to establish a reference line for the straightness measurement of any mechanical system. 4--Q detector is used to receive the laser beam. A chip microcomputer is developed to conduct alldata acquisition and signal processing. The beam drift influence can be removed in the greatest extent from the system. The experiments on the measurement system stability,repeatability and its comparison with the HP5528 double--frequency laser interferometer are carried out.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Velocity measurement based on orthogonal CCD shadow photograph system in Ballistic range

A method of measuring the velocity of fast moving object by charge coupled device(CCD) shadow photograph system is developed.This system consists of high resolution orthogonal CCD cameras,time detecting device and the pulsed laser which can generate two short laser pulses with adjustable interval more than 100 μs.Experiments are conducted to measure the velocity of the flying steel ball.The results show that the proposed velocity measurement is effective in modern ballistic measurement.     

A non-contact gear measurement method based on laser vision

In order to classify the gears and achieve high precision measurement results, a non-contact gear measurement system based on the laser vision is developed in this paper. The laser vision precision measurement method （LVPMM） is pro- posed to ensure the accuracy. Experimental results indicate that the gear measuring uncertainty is 2.1 /am. The preci- sion can satisfy the gear measurement requirements for two-grade or under two-grade standard gears in industry, and can classifv the gears very well     

Performance analysis of quantum key distribution based on air-water channel

In order to realize the online measurement of lamp dimension,the bulb image dimension measurement based on vision(BIDMV)is proposed.The image of lamp is obtained by camera.After image processing,such as Otsu algorithm,median filter,ellipse fitting and envelope rectangle fitting,the dimension of lamp can be calculated.Based on this method,a non-contact real-time measurement system of the lamp’s dimension is developed.The precision of the proposed method is 0.07 mm,and it can satisfy the tolerance of the National Standard GB15766.1-2008.The experiment results show that the proposed method has a faster measuring speed and a higher precision compared with other measurement methods.     

Photoelectric Inspecting Techniques for Parallelism and Swaying of Rocket

Introduced is a traditional method for measuring the swaying and multi-barrel parallelism, and deficiencies are analyzed too. Based on that, expatiated is a new method of using a set of equipments to measure the two parameters synthetically, adopting integrative photoelectric inspecting technique, laser technique and computer picture processing technique.     

Marine Mobile Wireless Channel Modeling Based on Improved Spatial Partitioning Ray Tracing

In 5G era,it is expected to achieve wireless network coverage including offshore areas.Modeling of marine wireless channels is the basis of constructing a marine communication system.In this paper,a communication scene between an unmanned aerial vehicle(UAV)and a boat is simulated to study the marine wireless channel.Firstly,an improved spatial partitioning ray tracing algorithm is proposed to track the propagation path of electromagnetic waves at sea surface.Secondly,a mobile channel is simulated and modeled based on the track results.Finally,a loss measurement is carried out in the coastal waters based on the simple wireless channel loss measuring platform,and a path loss propagation model is built.Then we compare the actual measurement data with the simulation results and find that the two are have good consistency,which further verifies the reliability of the simulation.     

High Speed Laser 3D Measurement System

Using the method of line structure light produced by a laser diode, three dimensional profile measurement is deeply researched. A hardware circuit developed is used to get the center position of light section for the improvement of the measurement speed. A double CCD compensation technology is used to improve the measurement precision. An easy and effective calibration method of the least squares to fit the parameter of system structure is used to get the relative coordinate relationship of objects and images of light section in the directions of height and axis. Sensor scanning segment by segment and layer by layer makes the measurement range expand greatly.     

CCD的非线性响应特性对光束质量测量的影响及修正

在利用电荷耦合器件CCD对激光光束质量测量的过程中,通过对比不同的激光波长,分析了CCD的光电响应非线性特性对光束质量M2因子评价的影响。由于对未进行线性标定的CCD所测得的四种不同波长的激光器的光束束宽值相对比较大,这会对激光光束质量的测量精度带来影响,因此提出了一种新的基于面阵型光电探测器的光电响应标定方法。搭建基于CCD测量法的激光光束质量测量系统,建立高斯型激光光束的近远场传输模型,对激光束在传输方向上不同位置处的焦散廓形进行多次采样,利用统计学方法得到CCD的光电响应线性区间。仿真和实验结果表明:利用CCD光电响应特性的标定结果对图像进行非线性灰度修正,对比国际标准激光光束质量分析仪,所测得的激光光束质量M2因子更加准确且相对误差降低了2.36%。提出的方法可有效提高激光光束质量M2因子的测量精度,对于评价激光光束质量具有重要的应用价值。     

基于CCD的脉冲激光器远场发散角工程化研究

简述了激光光束的基本参数及特性,并介绍了采用CCD进行激光发散角测量的基本原理和装置.用CCD测量光斑可以及时获得光斑的二维扫描结果.实际工程应用时常采用CCD来测量激光远场发散角.进一步介绍了使用CCD摄像法进行发散角测量所采用的系统软件设计,首次提出了采用图像处理的方法来捕捉脉冲激光光斑.     

固体激光远场瞬时光斑时空分布测量技术

基于漫透射CCD成像法原理,建立了固体激光瞬时光斑时空分布测量系统。开展了该测量方法的可行性验证实验,能够精确地获得激光远场光斑图像,并运用Matlab软件对测量数据进行处理,得到激光远场光斑半径、光束质量、质心位置、光轴抖动、光强分布以及平均功率密度等参数。实验结果表明:利用漫透射CCD成像法测量固体激光远场瞬时光斑时空分布是可行的,测试系统采集频率可达120 Hz。该方法具有高分辨率、高帧频、低成本、使用方便的突出优点,能同时实现激光强度分布和功率的测量,测量功率误差小于2%。     

激光强度时空分布测量漫散射取样衰减技术研究

激光强度时空分布的测量对于诊断与评估激光系统的性能具有重要意义,减少激光入射角度影响、对大尺度激光束进行高分辨力、高占空比取样是准确测量激光强度分布的关键,结合漫散射光分布与入射光方向无关的原理,提出了激光强度时空分布测量漫散射取样衰减方法,设计了漫散射取样衰减单元,建立了光强计算模型,推导了光强计算公式并进行了验证,光强衰减倍数实验结果与理论值一致。介绍了漫散射取样衰减装置与光电管阵列或CCD成像系统的组合应用。该方法的优点:空间取样分辨力高,可达2 mm左右;使用角度宽,可达30而不需要响应修正;占空比高,可达40%以上;衰减倍数范围大,可以通过调节衰减结构参数实现任意需要的衰减倍数。漫散射取样衰减为阵列探测器对大尺寸激光束进行取样和衰减提供了一种新方法,提高了激光强度分布测量能力和测量精度。     

利用CCD测量液体折射率

提出一种利用ＣＣＤ测量流体折射率的简单方法,当一束激光斜入射到一个主以满液体的长方形样品池时,航向光线将产生一定量的偏移,利用ＣＣＤ自动测量这一偏移量,就可以很快地计算出流体的折射率。采用Ｈｅ－Ｎｅ激光测量了纯水、乙醇和丙酮的折射率。     

基于高斯光束的飞秒激光光束质量检测技术

为了研究飞秒激光光束质量因子M2基于高斯光束的传播特性和能量密度分布, 在对飞秒激光光束质量因子进行理论研究的基础上, 进行了相应的数据计算, 给出了飞秒激光脉冲照射屏幕表面时所形成的环形光斑宽度的测量方法, 设计了一套由飞秒激光器、透镜、介电材料玻璃屏幕所组成的实验平台; 将该方法与刀口法和CCD法测量值进行了对照, 并用刀口法、CCD法确认了飞秒激光束腰在不同位置时的激光光束质量因子取值范围。结果表明, 光束质量因子M2在x和y方向上的测量值分别为2.04, 1.24。该实验结果与理论分析基本一致, 比刀口法和CCD法结构简单, 所得结论数据可靠、执行方便, 对精密测量有一定的参考价值。     

基于线阵CCD的线路方向测量系统的开发

该系统硬件设备采用长距离准直激光光源、CCD图像传感器、旋转编码器、系统终端PC等器件,利用线阵CCD测量技术、数据处理技术、多信息传感融合技术等高新技术,能够对铁路路轨区段(长度≤200m)轨道几何形状进行高精度检测,将线路轨向测量结果直接数字化显示,为线路设备维修提供可靠的测量数据,解决了既有方法测量精度差、效率低的问题,能满足铁路工务系统作业要求、提高作业质量。     

COIL光束填充因子F的实验研究

采用CCD阵列测量技术,设计了对非稳腔、高遮拦比的COIL激光填充因子F的测量系统,利用两台光束质量分析仪同时测量了激光近场和远场光斑,通过Matlab软件对光束质量分析仪所测数据进行处理,给出光束填充因子。在与测得的光束质量数据进行对比后表明,填充因子F与光束质量存在一定的关系,F值越大,光束质量越好。     

一种测量激光束横模结构的非线性网络

提出以激光束的横模结构特别是基模所占的比例作为激光光束质量的评价依据,并研究了测量方法.建立了基于Hopfield神经网络原理的非线性网络,使用CCD采集激光束的光斑图像作为网络的输入,通过计算该网络的能量函数,实行调整训练,获得网络的动力学稳定状态,此时网络中各阶横模的比例即为测量结果.实验采集了一束光的多幅光斑图像,经预处理后输入该网络,可获得模式结构数据,其中基模分量为69%.利用所得结果合成一幅光斑,与输入的原光斑图像的相对误差为3.53%.