基于改进加权局部对比度的红外小目标检测

在复杂背景的红外图像中弱小目标通常淹没在高亮边缘与强杂波处,提出一种基于改进加权局部对比度的红外小目标检测方法。利用小目标的局部特性建立一种加权函数将目标与其背景邻域的差异点乘凸显目标,进而与相接背景邻域作比值运算达到抑制复杂背景的效果;通过目标的各向同性和背景的各向异性,采用六方向梯度决策法创建背景抑制模型进一步抑制高亮边缘,实现降低虚警率,提高检测率的目的;最后,通过卷积计算将两者结合,采用自适应阈值分割检测真实目标。实验结果表明,该算法在复杂背景及强杂波干扰下有较强的鲁棒性。     

基于MRF的自适应正则化红外背景杂波抑制算法

针对复杂背景下红外弱小目标检测难题,将背景杂波抑制归结为从原始红外弱小目标图像中重建目标数据的过程,据此提出了一种基于马尔可夫随机场模型(MRF)的自适应正则化滤波算法.该算法采用MRF,建立了红外弱小目标图像的先验概率模型,并根据图像的粗糙度设计了新的势函数.在此基础上,采用MRF对背景杂波抑制过程进行正则化处理,从而实现了对红外背景杂波的自适应各向异性抑制.理论分析与实验结果表明,该算法能够随图像局部纹理特征的变化自适应地调整滤波算子结构,从而可在复杂背景下自适应地抑制杂波、增强信号,有效地提高了图像的信噪比,且该算法结构简单,更易于硬件实时实现.     

双邻域差值放大的高动态红外弱小目标检测方法（特邀）

针对现有红外弱小目标检测方法背景抑制不充分、计算复杂度高,导致红外侦察预警系统虚警率高、响应速度慢的问题,提出一种基于双邻域差值放大的高动态红外弱小目标检测方法。首先,分析真实红外图像中目标与邻域的均值特性;然后,计算出目标区域与内外双层邻域的差异,从而提升亮、暗弱小目标的局部对比度并抑制复杂背景和噪声;最后,利用自适应阈值分割算法获取目标的位置。针对信杂比增益和背景抑制因子难以客观评价红外图像序列的目标增强和背景抑制性能的问题,提出一种目标轨迹显著图评价方法,有效评价红外图像序列目标检测性能。实验结果表明:与同类检测方法相比,该方法的信杂比增益与背景抑制因子分别提高了12%与10%,运行时间约缩短了34 ms,是一种有效可行的高动态红外弱小目标检测方法。     

基于复杂背景的红外弱小目标识别

为了降低红外图像中弱小目标检测的虚警率,提升图像边缘处理效果,提出一种基于局部对比度联合facet小面模型的红外弱小目标检测改进算法。首先采用高斯滤波去除图像中高斯噪声。然后,利用改进算法进行图像子块遍历,去除图像中可疑的弱小目标。最后,利用facet模型方向导数特征得到不同方向的弱小目标梯度分布,使算法具有良好的边缘处理特性,从而获得待处理图像中真实的弱小目标。实验结果表明,与传统算法相比,改进算法的虚警率最低,大大提高了图像边缘处理效果。     

基于梯度特征的弱小目标检测北大核心CSCD

针对传统检测方法对低对比度和低信噪比弱小目标检测难度大的问题,提出一种基于梯度特征提取的弱小目标检测方法。首先利用弱小目标的各向同性及在梯度空间中的正负分布特性,提取两个方向梯度特征;然后通过改进的局部对比度算法分别抑制两个方向梯度特征的相似性,融合两个抑制相似性的方向梯度特征,增强目标同时抑制背景;最后通过自适应阈值对结果图进行分割,得到最终检测结果。实验结果表明,该算法不仅能够有效检测极低信噪比与对比度的目标,而且对复杂边缘场景具有很好的抑制效果,在信噪比、背景抑制因子以及检测率方面优于其他算法。     

基于杂波抑制的海平线红外弱小目标检测

针对红外图像中海天交接处目标能量较弱,难以获得精确检测的问题,本文提出一种基于杂波抑制的海平线弱小目标检测方法。该方法通过对红外图像特征分析,检测海平线像素特征,去除障碍物干扰,确定海平线区域;对海平线区域采用改进的均值差滤波与背景建模,去除海平线杂波;杂波滤除后,计算两个区间自适应阈值作为滞后阈值,从而检测出海平线弱小目标像素。实验结果表明,本文提出的算法能够有效去除海平线杂波,确定海平线区域,有效提取海平线像素,从而准确检测出海平线弱小目标,具有较高的检测率与较低的虚警率,验证了该算法的有效性。     

基于权重强化局部方差对比的红外小目标检测

针对红外图像中背景与目标对比度低、边缘高亮的问题,提出了一种用于红外小目标检测的局部方差对比测度算法.该算法由局部方差对比测度的计算和权重强化函数的设计两个模块组成:局部区域对比利用目标区域三层图像块模型之间的方差差异突出增强真实目标;权重强化函数的设计是为了能更好地抑制背景杂波,充分考虑了目标的统计特征、目标与其相邻背景的统计差异和背景的统计特征.实验结果表明,该方法在增强小目标和抑制背景杂波方面具有较好的效果,时间较短,鲁棒性好.     

RBNSM:一种复杂背景下红外弱小目标检测新方法

弱小目标检测是红外探测与跟踪任务中的经典难题。针对复杂背景下红外弱小目标普遍存在检测率低、虚警率高的问题,提出一种基于区域双邻域显著图（Regional Bi-Neighborhood Saliency Map,RBNSM）的复杂背景红外弱小目标检测新方法。利用弱小目标的局部先验特性定义滑动窗口并划分为多个单元,计算中心单元前若干个最大灰度的均值来凸显弱目标;分别构建中心单元的相接邻域和相隔邻域并计算各自的灰度均值,进而,从不同方向上提取两邻域显著图并点乘二者以进一步抑制杂波背景、增强弱小目标;最后,通过自适应提取准确检测目标。多种典型红外复杂背景图像和SIRST数据集检测结果表明:与7种代表性方法相比,RBNSM在复杂背景下具有更好的检测性能与杂波抑制能力。     

基于视觉对比机制的红外弱小目标检测方法

为解决复杂背景下红外弱小目标检测精度低的问题,本文提出一种基于视觉对比机制的红外弱小目标检测方法,算法主要模拟了人眼对目标对比度敏感这一机制。首先利用8向梯度方程提取红外图像的梯度显著图并二值化处理;根据小目标的尺寸大小特征对梯度显著图进行优化处理,剔除孤立的噪声点和尺寸较大的背景梯度显著区域;利用视觉对比机制对优化后的显著图进行局部对比度计算,通过阈值处理剔除虚警目标,完成红外弱小目标检测。仿真实验表明,该算法在低信噪比情况下对红外弱小目标的检测率较高,且虚警率低,单帧检测时间较小。     

基于多方向梯度和形态学算法的红外弱小目标检测

受多种因素的影响,通常获得的红外图像信噪比低、对比度差,为目标的提取带来一定的困难。在分析弱小目标方向梯度的基础上,结合形态学算法,提出一种新的红外弱小目标检测算法。首先在待检测点四邻域方向上选取4个参考点,根据该方向待检测点与参考点之间的多级梯度特征,确定出潜在目标;然后利用结构元可调节的特性,选择合适的结构元素,通过形态学处理,剔除噪声点并最终确定出目标。实验表明,该算法计算简单,无需预测背景,可在低信噪比图像中有效检测弱小目标。     

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.