人眼波像差测量中形心探测的新方法

子孔径光斑的形心探测和计算精度是影响哈特曼传感器波像差探测精度的重要因素，而探测窗口的选取对探测误差的影响很大。分析了Prieto等人采用的逐步缩小窗口尺寸的探测方法，并根据哈特曼波前传感器探测人眼波像差的光斑特点，采用模板匹配法选取光斑窗口的形心探测方法。该方法与Prieto的方法相比提高了探测精义。光斑阵列的仿真计算结果表明，用文中采用的方法探测误差的均方根值降低了53．7％。另外，该方法还避免了Prieto方法中多次迭代计算，减少了运算量。     

提高波前探测精度的高阶矩方法

夏克-哈特曼波前传感器测量畸变波前的探测精度主要取决于光斑质心的测量精度。提出了一种提高光斑质心探测精度的新方法,在优化的探测窗口内使用高阶矩方法计算光斑的质心。首先,在整个子孔径内,通过一阶矩方法获得光斑的近似中心,然后以这个近似中心为中心,包含整个光斑,建立一个矩形窗口,并在该窗口内通过高阶矩方法重新计算光斑的质心。通过该改进的方法,在优化的探测窗口外,噪声的影响基本被消除;在优化的探测窗口内,噪声的影响也因为光斑权值比重的增大而削弱。实验结果证明:与传统方法相比,新方法提高了光斑质心测量的精度、重复性和稳定性。     

哈特曼波前传感器光斑质心探测窗口的自动确定方法研究

根据在进行激光系统输出波前诊断时使用Hartman传感器探测到的光斑特点,提出一种基于光斑特征识别的自动搜寻并选取光斑质心探测窗口的新方法。通过对仿真光斑阵列的计算和对实际采样图像的实验,验证了这种方法的可行性和探测精度。     

哈特曼-夏克波前传感器的高精度质心探测方法

为提高哈特曼-夏克波前传感器(HS-WFS)的光斑质心探测精度以实现光学系统的高精度波前检测,提出了一种有效的质心探测方法。该方法利用非线性滤波和窗口法对整幅光斑图像进行全局处理后,结合中值滤波、三次样条插值和自适应Otsu阈值法对单个光斑进行局部处理。分析了三次样条灰度插值点个数不同,探测精度和计算时间的变化规律。采用该方法探测了含有噪声的光斑图像,其质心探测误差仅为0.0442pixel,比传统的非线性滤波、Otsu阈值法和探测窗口法探测精度分别提高了91.86%、87.97%和31.79%。对已知波像差的光学系统进行了仿真检测,得到的波前检测精度峰谷(P-V)值为0.0098λ,精度均方根(RMS)值达到0.0027λ。结果表明该方法能够提高质心探测精度,可用于高精度光学系统的检测。     

Shack-Hartmann 波前传感器质心探测的优化方法

为提高Shack-Hartmann(S-H)波前传感器的光斑质心探测精度,在分析质心探测误差来源的基础上,提出基于模板匹配的探测窗口选取方法和基于单个光斑的自适应阈值选取方法,将这两种方法与加权质心算法相结合求取质心,提高了质心探测精度。与固定阈值和传统质心算法相比较,当SNR 大于3 时,质心探测精度平均提高了约40%。将文中的方法应用于可见光波段的商品S-H 波前传感器,实验表明:文中方法得到的质心偏离度由传统方法的0.83 pixel 的最大值减小至0.15 pixel。该工作有重要的应用价值。     

Hartmann-Shack波前传感器的自适应质心探测方法

在分析影响Hartmann-Shack(H-S)传感器质心探测精度因素的基础上,提出结合自平方算法、大津算法、光斑位置区域自适应标定、回归局部阈值法等方法,给出一套适合波前像差测量的质心自适应探测方法,该方法具有准确、自适应性强的特点.经验证,与传统的质心探测方法相比,该方法能准确识别并保留更多的有效光斑信息,提高质心探测的精度,扩大H-S传感器的适用范围.     

基于图像处理技术的光斑质心高精度测量

针对传统的光斑质心测量方法子孔径窗口内远离光斑的噪声对一阶矩质心算法的影响,本文提出一种利用图像处理技术提高光斑质心探测精度的新方法。在哈特曼-夏克（H-S）波前传感器测得的光斑阵列图像中,采用自适应阈值方法优化每个子孔径的探测窗口,使探测窗口和光斑分布区域最佳匹配;然后在探测窗口内,采用线性插值方法提高图像的分辨率。...     

光斑图抑噪预处理的方法研究

为了提高光斑的质心探测精度,要对采集的光斑图在质心位置确定之前进行抑噪预处理,采用5种常用的图像处理方法对光斑图进行抑噪处理。仿真和实验结果表明,两种非线性滤波算法效果最好,极大地提高了质心探测精度,为波前相位探测中的数据处理提供了有益的参考。     

基于近红外CMOS的激光光斑质心检测系统设计

为实现在复杂背景光照条件下具有较高的光斑探测灵敏度,高精度的坐标计算,及大于1000 fps的结果输出速度,介绍了一种基于近红外CMOS图像传感器,实时计算光斑质心坐标并输出的系统.设计使用安森美半导体公司的Python1300系列近红外图像传感器NOIP1FN1300A对激光光斑成像.利用Cyclone4系列低功耗F...     

夏克—哈特曼波前传感器的探测误差

夏克—哈特曼（S－H）传感器的探测误差是自适应光学系统的一个主要误差源。本文主要分析了S-H传感器的系统误差和随机误差，其误差源包括：CCD相机的读出噪声和背景电平，探测的像素数以及光子噪声。通过在计算哈特曼传感器子光斑质心时设定一个阈值可以大大提高传感器的探测精度。本文同时列举了实验数据和理论分析结果。     

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