序列图像轴对称物体中轴线提取方法

针对轴对称目标三维姿态参数中的偏航角、俯仰角的提取问题,提出了一种自动提取目标中轴线方法.该方法运用自适应Canny算子检测目标边缘,改进的Hough变换获得边缘图像中各条直线边缘的坐标点;通过优化的最小二乘算法将各条直线边缘的坐标点进行拟合获得边缘直线方程;结合序列图像中目标特性,检测出边缘直线中特定的两条平行直线进而获得目标的中轴线方程.实验表明:该方法能够有效地、高精度地提取轴对称目标的中轴线,提取的中轴线平均角度误差为0.022°.     

基于Hough拟合算法的对称目标姿态测量新方法

针对空中对称刚体目标,提出了一种基于Hough变换拟合算法的姿态测量新方法.它对于中轴线提取过程进行了改进,通过详实的仿真实验和精度分析,证明该算法在一定程度上提高了中轴线测量法的抗噪性和测量精度,且易于实现,对于实际的工程应用具有一定的借鉴价值.     

一种基于虚拟目标的飞行器姿态测量方法

提出了一种使用虚拟目标代替真实目标对姿态测量系统进行测试和评估的方法,同时给出了由光学成像设备跟踪状态和目标飞行状态计算目标在光学成像设备像面上成像中轴线斜率和截距的算法.根据姿态测量系统的特点,仿真出大量具有针对性的理论数据和图像,并使用其对姿态测量系统中的图像判读精度和姿态交会算法分别进行了测试和评估.实验结果表明,当虚拟目标长度在80 pixel时,提取精度可达0.1°;而当虚拟目标长度在6 pixel时,提取精度仅为5.7°;姿态交会算法对判读误差具有一定放大作用;图像判读误差是姿态测量中的主要误差源.     

一种多目标ISAR成像方法

在逆合成孔径雷达(ISAR)多目标成像中,当各目标相互靠近且目标相对雷达的径向速度又相差较大时,存在使用已有的多目标成像方法无法对其成像的问题,文中提出了一种结合Radon变换、包络相关和DCFT的多目标成像方法。该方法采用Radon变换估计目标个数并对目标包络进行粗对齐;用传统的包络相关法结合目标隔离和曲线拟合法对目标进行精确的包络对齐;通过DCFT算法完成相位补偿,最后获得多个目标清晰的ISAR像。仿真实验结果验证了该方法的有效性。     

SAR微动目标检测及其参数估计方法

针对机载合成孔径雷达（SAR）系统在环境变化比较剧烈或者载机飞行不稳时噪声较大的问题,提出了基于信号时频分析和逆Radon变换的微动目标检测与参数估计方法。首先对振动目标回波信号作DPCA处理;然后对其进行时频分析,提取微动目标的微多普勒特征;最后对时频分析后的信号进行逆Radon变换,估计振动目标参数。干涉信号的微多普勒频率表现为正弦函数的形式,逆Radon变换对正弦信号聚焦但对噪声不聚焦,整个系统所需回波信噪比使用时频分析时低得多。仿真实验验证了算法的有效性。     

Radon变换的计算机模拟

从数学上,严格论述了Radon变换的概念和数学意义。将Radon变换的数学坐标系统直接建立在物理场上,不仅将抽象的数学模型直观化,而且使Radon变换的物理意义简单明了。用三峰函数模拟了三维物体的切片,计算了该模拟平面场全方向180°范围内、角度间隔为1°的全部投影,从而给出了Ra-don变换应用于光学层析(OCT)的方法。     

多站ISAR空间目标姿态估计方法

该文提出一种基于多站逆合成孔径雷达(ISAR)序列成像的空间目标姿态估计方法。方法提取各帧ISAR图像中目标的典型线性结构,结合目标轨道信息实现关键部件姿态估计。该文建立了较为稳健的空间目标ISAR几何结构分析流程,采用Radon变换对太阳能翼、平板天线等线性结构进行提取和关联,继而估计典型线性结构在距离-多普勒成像平面的姿态角变化,同时利用卫星轨道信息获得ISAR距离-多普勒投影矩阵进行线性结构的3维姿态解算,最终实现典型部件姿态的优化求解估计。仿真实验验证了所提算法可有效实现空间目标典型部件的姿态估计,同时利用多站ISAR观测数据可有效提升算法的估计精度。     

转角速度矢量估计和三维ISAR成像

逆合成孔径雷达成像中,观测目标通常具有明显的几何特性,且随目标转角的变化,其在成像平面的投影也随之变化.提出了利用Radon变换估计线性几何目标在各次"快照"的变化位置,估计雷达视线角和转角速度的方向,并对其三维位置和二维ISAR像建立映射关系,获得三维图像.由于Radon变换对直线检测具有很强的鲁棒性,该文的方法在已知目标转角模值的条件下对转角方向实现高精度估计,在此基础上可以对线性几何目标实现三维重构.仿真结果验证了算法的正确性.     

基于视频的投弃式温深仪速度测量技术研究

投弃式温深仪(XBT)的下降速率公式对XBT所测量的海水温度剖面有很大影响,通过分析视频测量系统所拍摄的XBT探头下落过程中的序列图像可计算其下落过程中的位姿参数并改进其下降速率公式.为测量XBT探头的下落速度,提出了一种基于积分投影和Radon变换的速度测量新方法.该方法无需复杂的图像处理算法及测量数据后处理算法,只需计算各帧图像的水平积分投影合成时间堆栈图像,根据时间堆栈图像的物理意义来确定目标运动轨迹的时空关系.通过对时间堆栈图像做Radon变换处理检测直线边缘特征,计算出目标的运动速度.实验表明,该方法简单、可靠,在图像质量较差的情况下仍能有效地计算出目标的运动速度.     

远距离运动目标三维测量中图像匹配的研究

采用两个摄像机光轴平行的双目立体视觉测量系统,检测远距离运动物体的三维物体轮廓.阐述了该三维轮廓测量系统中的两个关键技术:提取出合适的图像特征;建立特征间的对应关系.将同一空间物理点在不同图像中的映象点对应起来,由此得到相应的视差图像,实现立体匹配,恢复出物体的三维轮廓.仿真实验结果表明,该三维轮廓测量方法容易实现、对硬件要求不高、精度较高和具有较高稳定性,能够满足远距离运动物体姿态和速度测量的要求.     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

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.     

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.     

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.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.