局部保持鉴别投影及其在人脸识别中的应用

针对流形学习在人脸识别中的应用,该文提出基于局部保持投影(Locality Preserving Projection,LPP)的监督线性维数约简方法.利用样本的类别信息,将LPP的最近邻图分解为类内图和类外图,通过优化,最优保持同类数据固有的局部邻域关系,缩小数据之间的距离,同时最大化不同类数据之间的距离,从而增大各类数据分布之间的间隔,提高了嵌入空间的辨别能力.此外,在构建图的过程中采用了自适应邻域,增强了对数据分布稀疏性的表征.在Extended Yale B和CMU PIE两个开放人脸数据库上进行了试验,验证了算法的有效性.     

一种半监督稀疏保持近邻判别嵌入算法

保持近邻嵌入（NPE）算法对局部线性嵌入（LLE）算法进行了改进,克服了新来样本问题,但在处理分类问题上表现不足。本文提出了一种半监督稀疏保持近邻判别嵌入算法,该方法首先采用小波变换对数据进行预处理,然后执行等距离映射(Isomap)算法选择合适的低维嵌入维数,最后结合稀疏表示理论、NPE和线性判别分析（LDA）的思想,重构邻域图,并在建立目标函数时使得已标签信息中同类样本点之间相互靠近,异类样本点之间相互远离,未标签信息邻域信息得以保持,这样,既得到了高维映射函数,又提高了分类正确率。通过在人脸数据库上实验,并和其他半监督算法作比较,本文提出的算法在识别率上表现较好。     

基于局部保持判别子空间的ISAR目标识别

由于目标运动及其所处环境的复杂性,雷达目标数据之间往往呈现出局部的非线性,如果采用传统的线性子空间方法降维,必将会使雷达目标识别性能有所下降,基于以上原因,文章尝试将流形学习的思想应用于逆合成孔径雷达(ISAR,inverse synthetic aperture radar)目标二维像的目标识别.局部保持投影(LPP,locality preserving projections)是一类有效的流形学习算法,但它在构建权矩阵时没有充分利用样本的类别信息.针对此问题,提出了一种称为局部保持判别投影(LP-DP,locality preserving discriminant projections)的子空间学习方法,该方法通过构建类内和类间两个权矩阵来描述多类样本数据集的局部几何结构,以使在高维空间中相互靠近的同类数据点在低维嵌入空间中也相互靠近,而不同类的近邻点则尽可能地远离.对三类飞机目标的仿真实验结果表明,与PCA、LDA和LPP等算法相比,LPDP算法具有更好的识别性能.     

最大边缘准则图形嵌入在人脸识别中的应用

局部线性嵌入是一种有效地非线性维数约减方法,它能保持降维后的数据与原空间有相同的拓扑关系。但是这种方法在降维处理、可视化以及数据分类方面应用不是很广泛,针对上述问题,提出了一种新的、有效的降维以及数据分类方法——基于最大边缘准则图形嵌入方法。该方法首先构建最近邻关系图聚合数据点之间的最近邻样本,同时最大化类间间隔,保证不同类之间数据可分性大,从而更好地实现数据分类。最后,该方法的有效性分别在ORL及Yale两大人脸库上得到了验证。     

加权鉴别保持投影降维的非约束人脸识别研究

非约束环境下采集的人脸图像复杂多变,因稀疏保留投影(Sparse Preserving Projection, SPP)算法没有考虑到样本的局部结构使其降维效果不理想,针对该问题,本文提出了加权判别稀疏保留投影(Weighted Discriminant Sparse Preserving Projection, WDSPP)算法。首先,引入样本类别标签和类内紧凑项,用以增强待测样本和同类样本之间的重构关系;其次,非控环境下样本质量参差不齐,考虑以样本距离权值约束稀疏重构系数,降低同类奇异样本的影响,进一步提高重构关系的准确度;最后,低维投影阶段增加全局约束因子,利用样本全局分布中隐含的鉴别信息使低维子空间分布更紧凑、更易于鉴别。在AR库、Extended Yale B库、LFW库和PubFig库上的大量实验结果表明,本文所提算法在复杂人脸环境下具有较好的识别结果。       

基于随机子空间-正交局部保持投影的支持向量机

针对高维数、小样本数据分类问题,提出一种基于随机子空间-正交局部保持投影的支持向量机.利用随机子空间方法对原始高维样本的特征空间进行多次随机采样,生成多个具有不同特征子集的基支持向量机(SVM)分类器;利用正交局部保持投影对各基SVM分类器的样本进行特征提取,实现维数约简;然后,利用降维后的样本对各基SVM分类器进行训...     

自适应邻域选取的邻域嵌入超分辨率重建算法

在邻域嵌入超分辨率重建算法中,训练和重建过程均在特征空间进行的,因此,特征选择对算法的性能具有较大的影响。另外,大多数基于邻域嵌入算法对训练得到的样本库未经测试直接使用,使得邻域选择具有“盲目”性。考虑到特征选择的重要性以及避免邻域选择的盲目性,本文提出了一种新的邻域嵌入超分辨率重建算法。第一步:利用专家矢量场模型估计出输入图像的全局图像;第二步:利用邻域嵌入算法重建残差图像。在重建残差图像的过程中,首先将图像分成若干子块并利用线性滤波器提取特征;然后,将训练图像分成两组,第一组训练得到高、低分辨率重建样本库,第二组对重建样本库测试,得到邻域选择库;最后,自适应的选择输入图像子块的邻域数目,并利用重建样本库重建。仿真实验结果表明,相比其他基于邻域嵌入算法,提出算法可以重建更多的细节信息和锐利的边缘,重建得到的高分辨率图像具有较高的主客观质量。      

基于核邻域保持投影的人脸识别

提出了一种有效的非线性子空间学习方法:核邻域保持投影.其主要思想是通过引入线性变换矩阵来近似经典的局部线性嵌入(LLE),然后通过核方法的技巧在高维空间里求解.经过推导,实际的子空间的计算可归结为标准的特征值分解问题而非推广的特征值分解问题.在AR人脸数据库上的试验表明该方法是有效的.     

应用于人脸识别的监督局部邻域保持嵌入算法

提出了一种应用于人脸识别的监督线性维数约简 算法。首先引入图像距离度量方法以确定人脸数据 之间的相似程度,之后将训练样本的类标先验信息融入到邻域保持嵌入(NPE,neighborhood preserving embedding)算法的目标函 数中,使得降维后的嵌入空间的投影数据呈多流形分布,不仅最优保持了样本空间的局部几 何结构,同时各类样本 投影的类内散度最小化,类间散度最大化,增大了各类数据分布之间的间隔,提高了嵌入空 间的辨别能力。在Extended Yale B和CMU PIE两个开放人脸数据库上进行了识别实验,结果表明,本文算法取得了很好 的识别效果。     

空间一致性邻域保留嵌入的高光谱数据特征提取

局部线性嵌入(LLE)和邻域保留嵌入(NPE)等流形学习方法可以提取高光谱数据的主要结构特征,有助于对数据的理解和进一步处理。但是,这些方法忽视了高光谱图像中相邻像素之间的相关性。针对这个问题,提出一种基于空间一致性思想的邻域保留嵌入(SC-NPE)特征提取算法,通过一个优化的局部线性嵌入,并考虑相邻像素的相关特性,在高维空间建立数据的局部邻域结构。然后寻找一个优化的变换矩阵,将局部邻域结构投影到低维空间,实现数据的特征提取。与LLE和NPE算法相比,SC-NPE既考虑高光谱数据的流形结构,又考虑了其图像域空间信息,可以更好地应用在高光谱数据的特征提取过程中。实验结果表明,SC-NPE特征提取算法在高光谱图像分类方面的性能明显优于其他同类算法。     

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.