基于标记点的直升机旋翼动态三维测量方法

为快速方便地获取直升机旋翼动态三维坐标,提出了一种基于编码标记点和立体视觉的旋翼动态三维测量方法,该方法首先采用平面标定法及Bouguet校正算法实现立体标定和图像校正;其次,依据标记点形状和灰度特征,采用图像二值化和连通域标记等方法检测并定位编码标记点的中心,确定标记点像素坐标;然后,采用邻域扫描法对编码点进行解码,得到标记点的码值,并依据码值实现左右视图中同名标记点匹配;最后,利用投影方程求出标记点三维坐标,实现直升机旋翼动态三维测量。仿真实验结果表明该方法精度高,实际测量误差不超过0.3mm,可满足旋翼动态三维测量的要求。     

基于角点检测的双目视觉测距新方法

为解决双目视觉中立体匹配困难、效率低的问题,提出了一种基于角点检测的人工匹配方法实现双目视觉测距。首先介绍了双目测距基本原理,对摄像机进行了标定,并采用Bouguet立体校正算法对双目视觉系统进行立体校正;然后采用J.Shi和C.Tomasi提出的角点方法对立体校正后的左右摄像机图像中被测目标上的同一特征点进行了亚像素级角点提取,并利用提取的匹配角点坐标结合双目视觉测距公式实现距离测量。     

基于角点检测的双目视觉测距新方法

为解决双目视觉中立体匹配困难、效率低的问题,提出了一种基于角点检测的人工匹配方法实现双目视觉测距。首先介绍了双目测距基本原理,对摄像机进行了标定,并采用Bouguet 立体校正算法对双目视觉系统进行立体校正;然后采用J．Shi 和C．Tomasi提出的角点方法对立体校正后的左右摄像机图像中被测目标上的同一特征点进行了亚像素级角点提取,并利用提取的匹配角点坐标结合双目视觉测距公式实现距离测量。     

基于Harris-SIFT算法的双目立体视觉定位

针对基于尺度空间对图象保持不变性的SIFT算法在双目立体视觉应用时实时性差、误匹配等问题,提出一种运用Harris-SIFT算法进行双目立体视觉定位方法.通过介绍双目立体视觉的模型原理,利用Harris-SIFT算法从左右摄像机分别获取的图像中检测目标,并获取匹配目标的特征点,对两幅图像中目标物体的坐标标定,通过计算可得到目标物体的深度距离,还原其三维信息.实验证明,运用Harris-SIFT算法使该系统的实时性能和距离精度得到提高.     

基于双目视觉的医疗机器人摆位系统测量方法

为了实现精确放疗过程中精确定位和肿瘤位置的精确测量,建立了基于双目视觉的医疗机器人摆位测量系统,并对系统所采用的摄像机标定方法、标记点识别及其三维坐标计算、摆位系统的位置验证等算法进行研究。建立基于双目视觉的医疗机器人摆位测量系统;提出了一种对摄像机采用基于平面棋盘格和立体标定模板相结合的摄像机标定新方法;采用Roberts梯度算子对图像分割的方法,识别标记点中心并计算其三维坐标;通过比较基于双目视觉计算和三维坐标测量仪器测量的各个标记点三维坐标的摆位误差,实现放疗过程中位置验证和精确摆位。实验结果表明:摄像机的标定精度为36.5×10-3 mm和各个标记点的三维坐标平均偏差为δX=0.573mm、δY=0.495mm、δZ=0.430mm,测量方法可获得较高的标定精度和摆位精度,能满足精确放疗对高精度摆位系统的临床需求。     

基于超分辨率角点检测算法的双目相机高精度标定方法

双目相机标定是研究立体视觉的基础工作，标定的精度是视觉测量精度的关键。图像角点提取是相机标定的基础，但在现实应用场景中，外界影响使获取的图像不清晰，导致检测到的角点精度低，从而影响标定的精度。因此，提出一种基于超分辨率亚像素角点检测的端到端算法，从特征级解决低质量角点检测问题。首先，应用盲超分部分估计低分辨率图像模糊核，融合低分辨率图像特征重建出高分辨率图；然后，在此基础上得到角点亚像素位置；最后对双目相机进行高精度标定，并用测距实验对其进行检验。实验结果表明，所提基于超分辨的亚像素角点检测方法在真实场景下具有优越性。     

基于自标定双目视觉算法的3维图像构建

为了解决传统双目视觉标定方法构建3维图像的缺点,采用自标定双目视觉算法建立了双目视觉系统,确定了空间对象点;通过自标定数学模型构造矩阵,对两相邻图像的本质矩阵求解;并用立体空间方程的投影矩阵得到4个线性方程,用外极线约束法得图像点的世界坐标值。结果表明,物体空间轮廓清晰,避免重影,不再具有双重轮廓,3维表面比较逼真,具有较强的立体感。     

直升机桨叶共锥度测量中圆形标记点高精度定位方法

针对直升机桨叶共锥度测量中背景复杂、圆形标记点较小,易出现定位不准的问题,提出一种新的圆形标记点定位方法.首先,利用OTSU图像分割方法计算阈值;然后,以OTSU阈值为边界阈值,对图像进行多重分割;利用圆度特征和质心变化规律,对每一次分割后的连通域轮廓进行干扰排除,实现圆形标记点的粗定位;最后,采用最小二乘拟合法完成标记点的精确定位.通过圆形标记点定位实验,表明该方法在复杂场景下对较小的圆形标记点具有较高的定位精度,可用于提高大场景复杂环境下直升机桨叶共锥度测量精度.     

一种基于最小二乘法直升机旋翼桨叶挥舞角测量方法

为实现直升机旋翼桨叶挥舞角的测量,提出一种基于最小二乘法的测量方法。该方法使用双目视觉技术实现旋翼桨叶特征点的提取;使用最小二乘法对特征点三维信息进行处理,得到转轴方向向量和旋翼中心等参数;根据所得参数建立旋翼坐标系,并计算得到挥舞角大小。     

基于双目视觉的人体头部尺寸测量方法研究

为了CT系统进行定位片扫描时能够快速且准确的确定头部的扫描范围,提出了一种基于双目立体视觉的测量方法。方法能够在非接触环境下获取人体的头长和头宽。使用双目相机作为人体图像的采集设备,利用MATLAB、VS2017开发平台,使用张正友标定法标定双目相机获取相机内部参数。使用GrabCut图像分割算法对图像进行预处理,将前景的人体图像与背景分割。将立体校正后的左右图像通过SGBM算法进行立体匹配获得视差图,进而得到头部关键点的三维坐标,计算出人体的头长和头宽。实验结果表明该方法测量准确,误差小于1 cm。     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks