基于DSP的改进粒子滤波算法研究

介绍了粒子滤波基本原理,针对粒子滤波计算量大和难以用硬件实现等缺点对粒子滤波算法进行了改进,使其平均计算周期缩短为原来的90%,应用DSP实现了粒子滤波算法。改进粒子滤波算法主要优化了原粒子滤波算法中权值计算、重采样和输出步骤,使其计算速度和滤波精度有所提高。这种改进粒子滤波算法在DSP系统中进行仿真,结果证明它具有速度快,精度高的优点。     

一种改进的粒子滤波重采样算法研究

粒子滤波是基于递推的蒙特卡罗模拟方法的总称,可用于任意非线性,非高斯随机系统的状态估计.为了减轻退化现象,引入重采样过程,但重采样过程算法复杂,计算量大,不利于硬件实现,并且会削弱粒子的多样性,从而导致滤波性能下降.提出了一种将局部重采样和优化组合算法结合的重采样算法.将粒子按权值大小分类,小权值的粒子抛弃,大权值的粒...     

代表点理论在粒子滤波算法中的应用

将统计学中的数论方法应用于粒子滤波,使用随机分布的均方差代表点,对粒子滤波中关键的初始粒子生成、重点密度采样及再采样过程给出了相应的代表点算法,得到了一个包含最少随机操作的、使用非等权值粒子的改进粒子滤波算法.     

基于流水线高斯粒子滤波的无人机姿态估计算法及FPGA实现

采用高斯粒子滤波算法进行姿态估计算法设计,将四元数离散方程作为状态方程。算法由采样调节粒子、采样粒子、权值计算、均值协方差计算和Cholesky 5个模块组成。通过采用非标准化权值计算四元数"平均"值和协方差阵,并且改写协方差阵计算公式,实现流水线高斯粒子滤波算法。同时提出了并行化设计方案,利用FPGA剩余资源进一步优化运行速率。给出的简化粒子滤波算法与高斯粒子滤波算法设计不仅可用于无人机姿态估计,对于其他非线性估计问题及应用亦适用。仿真结果表明了本设计的可行性和有效性。     

基于颜色直方图的粒子跟踪算法在视频监控中的应用

摘 要：本文通过对跟踪目标颜色特征的分析,采用了基于颜色直方图的粒子滤波跟踪算法对目标进行实时跟踪。该算法首先确定目标跟踪模型并归一化颜色直方图,其次设定粒子初始化参数、计算粒子参数、比较颜色直方图从而确定目标位置,最后通过重采样更新粒子。该算法充分利用颜色直方图作为目标的描述特征,同时兼顾粒子滤波对复杂环境的要求,可以实现非线性和非高斯噪声系统的目标跟踪。仿真效果表明,该算法可以很好的对单目标和多目标进行实时跟踪。     

基于FPGA实现粒子滤波算法的实时细胞跟踪系统设计

面向背景是静止的运动细胞图像序列,通过简化粒子滤波算法并在FPGA实现其硬件逻辑来设计快速跟踪系统。其是按照目标辨识和跟踪要求,用模块化思想设计采样和存储模块、权值及阀值计算模块、重采样模块和状态估计输出模块后通过硬件描述语言VHDL下载到FPGA。针对单个细胞跟踪,单个细胞分裂跟踪和多细胞跟踪的测试对该系统的快速性和准确性进行验证。实验结果表明该系统满足对移动目标快速识别和跟踪要求。     

改进的粒子滤波算法

针对标准粒子滤波算法重采样后粒子多样性丧失问题,提出一种在粒子补偿的基础上,利用预测值与观测值的方差进行粒子重采样的改进粒子滤波算法。该算法是在标准粒子滤波算法的基础上,加入粒子补偿的步骤,然后利用预测值与观测值的方差在权值较高的粒子周围进行重采样来改善标准粒子滤波算法中粒子多样性丧失问题。实验结果表明:在相同条件下,改进粒子滤波算法比标准粒子滤波算法具有更小的平均均方误差(RMSE)和更高的目标跟踪精度,数据表明,其目标跟踪精确度提高30%以上。     

用于纯方位跟踪的简化粒子滤波算法及其硬件实现

针对粒子滤波运算量大,硬件复杂性高的问题,该文提出了一种用于纯方位跟踪的简化粒子滤波算法,该算法引入了一种新的基于阈值的重采样方法,降低了硬件实现的复杂度。在算法研究的基础上,论文研究了基于FGPA的硬件电路实现方法,给出了系统的整体硬件结构及重采样/采样模块的实现方案,讨论了粒子滤波硬件实现的资源优化及时间优化问题。仿真结果表明,对于纯方位跟踪问题,该粒子滤波算法具有优于扩展Kalman滤波器(EKF)的性能;硬件电路实验表明,该滤波器可以实现对被动目标的纯方位跟踪,并具有比通用粒子滤波器较快的处理速度。     

自适应差分演化粒子滤波器

针对非线性、非高斯系统中的粒子滤波算法存在粒子权值退化和重采样后引起样本枯竭问题,提出一种自适应差分演化粒子滤波算法。用一种自适应参数控制策略对差分演化算法的参数进行控制,并以此代替粒子滤波中的重采样算法。通过对状态更新后的粒子做自适应差分变异、自适应杂交和选择等优化操作,利用权值大小选出下一时刻的粒子集合。实验表明,该算法能有效缓解粒子权值退化和样本枯竭问题,缩短算法运行时间,提高估计精度,同一般的差分演化粒子滤波算法相比,状态估计的精度更高。     

同频不同速率数字调制混合信号的单通道盲分离

针对同频不同速率数字调制混合信号的单通道盲分离问题,建立了信号的状态空间转移模型,提出了基于粒子滤波的盲分离算法,并重点推导了重要性采样概率密度函数的表达式和粒子权值更新公式.仿真结果表明,粒子滤波算法可以对各项信号参数进行实时动态跟踪,从而有效的实现信号的分离.     

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.