基于激光视觉技术的运动目标位姿测量与误差分析

针对当前方法测量运动目标姿态和位置存在精度较低的问题,将激光视觉技术应用到运动目标位姿的测量中,提出基于激光视觉技术的运动目标位姿测量与误差分析方法。利用三维激光扫描仪和双目相机构成的系统,实现运动目标位姿的测量,分别采用三维激光扫描仪和双目相机采集运动目标的深度信息和二维图像信息,融合深度信息和二维图像信息,获取运动目标的位姿。通过三维坐标和光斑图像坐标、外部参数以及位姿解算之间存在的误差传递矩阵,构建运动目标位姿测量综合误差传递模型,利用误差传递模型对测量结果中存在的位姿误差进行分析,根据分析结果对运动目标位姿测量过程进行改进和优化,提高运动目标位姿测量结果的精度。在模拟风洞的实验环境中,验证了基于激光视觉技术的运动目标位姿测量与误差分析方法的可行性。     

基于多传感器融合的航天器间位姿参数估计

提出了利用单目视觉与激光测距仪混合的航天器间相对位置和姿态参数测量的解析算法。首先利用四元数测量算法,采用5个非共面特征光点和单目视觉获取航天器间相对位置和姿态参数的解析解,并对解析解进行修正;然后,将上述6D位姿参数与激光测距仪获取的1D距离进行融合,以进一步对6D位姿参数进行修正。最后,通过计算实例对该算法进行数学仿真,仿真结果表明:该算法保证了在相机标定和特征光点提取及匹配较大误差下的位姿参数的估计精度,能够满足航天器相对位姿确定精度和实时计算要求。     

位姿视觉测量方法及应用综述

位置和姿态参数是表征目标空间朝向和位置的基本几何量参数，比如飞行器的飞行位姿、高端装备大部件的对接位姿、自由运动中的人体位姿等。因此，位姿参数的准确快速测量一直是航空航天、国防军事、工业生产、体育竞技等诸多领域的重要研究内容，并发展出惯导、卫星、雷达、星敏感器和视觉测量等多种不同测量技术途径。本文重点针对位姿视觉测量方法及其应用进行了综述，主要内容包括位姿视觉测量基本原理、位姿视觉测量典型方法、多源数据融合的位姿视觉测量方法和位姿视觉测量典型应用领域。     

应用多传感器激光视觉的焊接机器人变质心补偿控制

制造、安装、机械传动和温度变化等诸多方面的误差较大,产生补偿机器人变质心偏移度,任务执行途中失去期望位姿,为了提高焊接机器人工作效率,提出应用多传感器激光视觉的焊接机器人变质心补偿控制方法。建立焊接机器人变质心模型,应用激光传感器扫描焊接机器人实际轨迹和位姿的几何特征,获取激光视觉图像标定管道焊缝,结合PLC控制器,调整焊接机器人轨迹和位姿,消除惯性力对变质心位移的干扰,实现焊接机器人变质心补偿控制。实验结果表明,在X-Y坐标面、Z-X坐标面和Z-Y坐标面上的变质心补偿轨迹均与期望轨迹误差5 cm左右,高度重合;控制后,焊接机器人惯性位移在0.1 cm之内,近似于零,惯性力不再引导焊接机器人移动,可以稳定停靠在目标位置,变质心控制性能好。     

基于最佳偏振角的线性位姿测量方法研究

在基于视觉图像的位姿测量中,非线性位姿测量算法的全局收敛存在不确定性,测量结果取决于初值的选取,不能保证位姿测量的鲁棒性。线性位姿测量算法对图像处理的要求比较高,如果定位特征点图像坐标提取不够精确,会导致位姿测量精度降低。在自然光条件下,相机采集定位特征点图像,图像中高亮度区域的存在对定位特征点提取精度产生影响,进而使有效定位特征点数量减少,影响位姿测量精度。针对上述问题,文中提出了一种基于最佳偏振角的线性位姿测量方法:在相机镜头前加装线偏振片,根据Stokes矢量建立偏振片最佳偏振角度求解模型,在使用最佳偏振角度的前提下采集定位特征点图像,提取图像坐标;建立线性位姿求解模型,计算被测物体位姿。实验结果表明,该方法能够有效减少图像中的高亮度区域,改善成像质量,提高线性位姿测量精度,在?60°~+60°的测量范围内,角度测量误差小于±0.16°,在0~20 mm的测量范围内,位移测量误差小于±0.05 mm。     

多像机非共视场的非合作飞行器位姿测量方法

以空间非合作飞行器视觉位姿测量为背景,针对近距离及超近距离情况下由于成像空间小、像机视场等限制,位姿测量所用的视觉特征将不能在单像机中完整成像而无法完成定位的问题,提出一种多像机非共视场的非合作飞行器位姿测量方法。首先将多个像机配置成非共视场的形式,标定各个像机之间的位置关系;然后利用多个像机对目标上的不同特征成像,来自不同像机的底层信息既有冗余又有互补,为位姿测量提供足够的视觉特征和几何特征;最后结合像机之间的位置关系将各个像机中的特征信息进行融合,进而以闭式解法计算目标位姿。实验结果验证了该方法的有效性以及在大目标近距离位姿测量应用中的优越性。     

高速列车动态位姿测量方法及校准技术研究

针对高速列车动态位姿测量中高速、大视场和高精度的测量需求,构建由两台高速相机组成的双目视觉测量系统,通过同步捕捉由大功率线激光瞬时光源构造的测量特征,实现对高速列车动态位姿的实时测量。提出基于非成像模型的相机校准方法,重构相机光学成像过程,构造三维空间成像光束和图像像点之间的一一对应关系,通过建立入射光束角度值与像点坐标的数学模型,实现大视场相机的高精度校准。基于光束平差原理,利用已知长度的基准尺实现双相机位置关系的快速精确校准。实验结果表明,采用上述方法可达到±5"的相机校准精度和±0.2mm的双相机校准精度,整个系统能达到±0.5mm的测量精度,为高速列车动态位姿的测量提供了一种全新有效的手段。     

直线匹配的四元数位姿估计算法

摄像机的位姿估计在计算机视觉和机器人学等领域得到了广泛的研究与应用。通过已知的3D几何特征和其对应的2D几何特征获得摄像机的旋转和平移参数是实现摄像机位姿估计的一种重要方法。在此基础上,文中针对单目相机位姿估计提出了一种新的基于3D~2D对应几何特征实现摄像机位姿估计的算法。该算法利用单位四元数表示旋转矩阵,通过建立位姿参数约束方程解出旋转和平移参数。相对于Ansar的NLL算法,该算法能更好地克服图像噪声对位姿计算精度的影响,且能保证其计算出的旋转矩阵具有正交性。模拟实验将该算法同NLL算法进行了比较,结果表明:该算法在鲁棒性、计算精度及复杂度等方面具有明显的优势,实验结果验证了该算法的有效性。     

基于视觉/惯导的掘进机实时位姿测量方法研究

针对煤矿井下掘进机实时位姿自动检测的难题,通过分析比较现有几种位姿测量方法的优缺点,提出了一种基于视觉/惯导的掘进机位姿组合测量方法。该方法通过激光捷联式惯导系统得到掘进机的姿态信息、单目视觉测量掘进机的位置信息,从而实现掘进机实时位姿的5自由度测量。依托大柳塔煤矿的快掘设备对该方法进行了实验验证。结果表明,姿态测量精度为0.1°,静态漂移的标准差不大于0.25°,位置定位精度优于1cm。该方法能够用于掘进机实时位姿测量,具有广阔的工程应用前景。     

六自由度工业机器人位姿误差的补偿方法

为了实现工业机器人的位姿误差补偿,在分析了机器人的位置误差和姿态误差的基础上,利用修正后的D-H算法建立了机器人运动学方程,并利用矩阵法建立了机器人的位姿误差分析模型。提出一种将机械结构参数综合映射到关节角度参数的补偿方法,并设计了一套适合此方法的补偿实验。通过对实验结果的分析与计算,验证了该方法适用于机器人位姿误差补偿,大幅度提高了机器人的绝对精度。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.