多传感器分布式推广卡尔曼滤波算法及其在雷达红外目标跟踪中…

本文提出了一种用于非线性系统的多传感器分布式推广卡尔曼滤波算法，该算法系统的动态方程和传感器的观测方程分别围绕全局估计和全局预测线性化，融合中心基于所有传感器观测的全局估计由各传感器基于自身观测的局部估计来重构。     

一种基于分步式滤波的数据融合算法

本文提出了一种基于分步式滤波的多传感器动态系统数据融合算法.在由多传感器组成的分布式动态系统中,当对目标状态的所有观测值到来时,首先基于系统先前信息对该时刻目标状态进行预测估计,利用Kalman滤波器和各局部观测值依次对该时刻目标状态的估计值进行更新,从而得到该时刻目标状态基于全局信息的融合估计值.文中详细推证了融合算法的具体形式,并与传统的集中式数据融合算法在计算复杂度上进行了比较,计算机仿真表明该算法与传统的集中式算法对目标状态具有相同的估计精确度.     

船舶动力定位多传感器闭环分级融合算法

为了改善船舶动力定位多传感器的融合性能,提出了一种多传感器闭环分级融合算法.该算法包括基于卡尔曼滤波的局部和全局两级估计,以全局融合信息的反馈作为局部估计的初始值进行时间更新,定义两级估计的映射关系并引入调节系数,自适应地调节全局融合增益.全局估计融入各局部估计过程中,两级估计组成了一个相互补偿的闭环系统.利用船舶半实物仿真系统的试验,仿真验证了该算法的有效性.     

单传感器多尺度状态融合估计算法

该文在离散小波变换理论和动态多尺度系统理论的基础上,建立了一种基于单传感器的多尺度状态融合估计新算法。该方法利用离散小波变换,对Kalman滤波模型的状态方程和观测方程分别进行多尺度处理,构建多尺度Kalman滤波模型,充分利用状态估计和观测数据在不同尺度上的特征进行融合估计,获得了优于单尺度Kalman滤波及已有多尺度状态融合估计方法的处理效果。并利用Monte Carlo仿真验证该算法的有效性。      

一种基于异步数据融合的传感器管理方法

针对多传感器系统存在观测数据过多,数据融合中心处理负担过重的问题,在引入一种基于传感器观测数据序贯处理的最优异步融合算法的基础上,提出一种基于目标协方差控制的传感器选择算法对异步观测数据进行优化组合,从而实现以最小的计算量达到所要求的目标状态估计精度。最后的仿真结果证明了该算法的有效性和可行性。     

多分辨率传感器多尺度融合估计算法

该文在基于信号统计特性的离散小波变换理论(DWT)和基于状态转移模型的动态多尺度系统理论(DMS)的基础上,提出了一种多分辨率传感器的多尺度状态融合估计新算法.该方法利用离散小波变换,首先对不同分辨率传感器Kalman滤波模型的状态方程和观测方程分别进行多尺度处理,构建统一的多尺度Kalman滤波模型,然后将不同分辨率...     

非线性系统的异步多速率数据 融合估计算法研究

 研究了一类非线性时变动态系统的状态估计问题,在不同传感器以不同采样率异步对同一目标进行观测时,提出了一种有效的数据融合估计算法.通过建立多尺度模型,将异步多速率系统形式转化为同步多速率系统;在每一步分别进行状态的预测和更新.在状态和观测预测时,采用强跟踪滤波(STF)算法;在状态更新时,采用有反馈分布式结构,顺序的利用每一个传感器的观测信息去更新状态的估计;从而基于给定的非线性系统模型,得到融合所有异步、多速率传感器观测信息的状态估计结果.该方法不需要对状态或观测进行扩维,计算量适当,从而保证了算法的实时性.仿真结果验证了算法的有效性.     

基于非合作目标的误差配准算法

误差配准是消除传感器系统误差必不可少的过程。针对非合作目标情况下如何估计传感器系统误差的问题,提出了一种基于线性卡尔曼和最小二乘的三维误差配准算法。该算法考虑了地球曲率的影响, 解决了传统的二维算法无法估计俯仰角系统误差的问题。通过构造系统模型, 将传感器系统误差和目标运动情况统一到同一量测方程中, 并结合线性卡尔曼和最小二乘得到系统误差的估计。仿真结果表明, 该方法能有效地估计包括俯仰角误差在内的多种系统误差。     

基于有理数倍采样的异步数据融合算法研究

本文研究了一类具有不同采样率的分布式多传感器动态系统的数据融合问题,针对一类采样率呈有理数倍关系的动态系统,提出一种基于多源异步采样数据的新融合算法.新算法首先是将来自各个传感器的测量值在融合中心的坐标系中和时钟下进行映射统一;其次,以对目标状态下一时刻的预测值与目标在该时刻状态的估计值之差为基础,建立起描述该融合周期内各个观测点处的目标状态向量之间的动态模型;然后,以该时刻目标状态基于全局信息的估计值为条件,结合建立的新模型和传统的Kalman滤波器,利用本周期内按序到达的各传感器观测值,依次对各个观测点处目标的状态进行估计和更新;最后,在顺序得到本周期内各个观测点处目标估计值的同时,也将获得下一时刻目标状态基于全局信息的估计值或预测估计值.文中在给出新算法基本思想的同时,也较为详细地对融合算法进行了推导,并通过计算机仿真的方法,将新算法与基于时间校准的算法在估计精确度上进行了比较,从而验证了新算法的有效性.     

基于序贯修正灰关联度的全局最优航迹关联算法

航迹关联是分布式多传感器航迹融合的前提。针对融合中心无法获得目标状态估计协方差的情形,该文提出一种基于序贯修正灰关联度的全局最优航迹关联算法。该算法取消数据列的区间值化,对数据列指标绝对差进行序贯积累,对灰关联系数计算式进行可交换性修正,得到各传感器航迹间的序贯修正灰关联度,以此关联度为全局统计量进行全局最优的航迹关联判决。仿真结果表明,在密集平行编队、随机交叉目标和存在非共同观测目标环境下,该算法的性能和稳健性明显优于传统方法。     

MULTISENSOR DISTRIBUTED EXTENDED KALMAN FILTERING ALGORITHM AND ITS APPLICATION TO RADAR/IR TARGET TRACKING

A multisensor distributed extended Kalman filtering algorithm is presented for nonlinear system, in which the dynamic equation of the system and the equations of sensor's measurements are linearized in the global estimate and global prediction respectively and the suboptimal global estimate based on all available information can be reconstructed from the estimates computed by local sensors based solely on their own local information and transmitted to the data fusion center. An analysis of the properties of the algorithm presented here shows that the global estimate has higher precision than the local one and smaller linearization error than the existing method. Finally, an application of the algorithm to radar/IR tracking of a maneuvering target is illustrated. Simulation results show the effectiveness of the algorithm.     

Global identifiability of nonlinear models of biological systems

A prerequisite for well-posedness of parameter estimation of biological and physiological systems is a priori global identifiability, a property which concerns uniqueness of the solution for the unknown model parameters. Assessing a priori global identifiability is particularly difficult for nonlinear dynamic models. Various approaches have been proposed in the literature but no solution exists in the general case. In this paper, we present a new algorithm for testing global identifiability of nonlinear dynamic models, based on differential algebra. The characteristic set associated to the dynamic equations is calculated in an efficient way and computer algebra techniques are used to solve the resulting set of nonlinear algebraic equations. The algorithm is capable of handling many features arising in biological system models, including zero initial conditions and time-varying parameters. Examples of usage of the algorithm for analyzing a priori global identifiability of nonlinear models of biological and physiological systems are presented.     

Distributed State Estimation for Discrete-Time Nonlinear System with Unknown Inputs

This paper investigated the problem of distributed estimation for a class of discrete-time nonlinear systems with unknown inputs in a sensor network. A modification scheme to the derivative-free versions of nonlinear robust two-stage Kalman filter (DNRTSKF) is first introduced based on recently developed cubature Kalman filter (CKF) technique. Afterward, a novel information filter is proposed by expressing the recursion in terms of the information matrix based upon DNRTSKF. In the end, distributed DNRTSKF is developed by applying a new information consensus filter to diffuse local statistics over the entire sensor network. In the implementation procedure, each sensor node only fuses the local observation instead of the global information and updates its local information state and matrix from its neighbors’ estimates using Average-Consensus Algorithm. Simulation results illustrate that the proposed distributed filter reveals the performance comparable to centralized DNRTSKF and better than distributed CKF.     

Ultrasonic multifeature maps of liver based on an amplitude losstechnique and a conventional B-scan

Recently, a novel ultrasonic amplitude loss technique for creating images of local tissue attenuation was presented. Based on this algorithm, global attenuation estimates were calculated and consistent variations of the estimated attenuation value was observed for different liver pathologies. With the exception of Hodgkin's and acute inflammatory liver disease, the detectability of the disease states was not increased by the global attenuation estimates. In an attempt to do so, pseudo-color maps were used in this study. The conventional B-scan was presented as a grey-scale image and a color-code attribute was based on the local attenuation estimate. In the vicinity of strong reflectors we noted a typical artifact. Modification of the classical physical model, describing the ultrasonic-tissue interaction, was observed to reduce the artifacts in the attenuation estimates; however, the detectability of disease states was not increased.     

确定分形函数的局部奇异性指数及其谱

基于配分函数的多分形形式仅仅提供了信号奇异性指数的全局描述,并没有给出局部信息,然而在实际应用中,揭示出信号的局部奇异性信息往往更具有重要性。该文提出了一种确定信号局部奇异性指数的新算法,构造了一种类似于奇异性谱的直方图,并用来描述信号奇异性的全局统计分布。数字试验验证了该算法的有效性。     

基于多速率传感器动态系统的多尺度递归融合估计

该文将基于模型的动态分析方法与具有统计性的多尺度信号变换方法相结合,基于最细尺度上给定的状态模型和不同尺度上给出的多速率传感器动态系统,建立了一组新的多尺度动态模型和多尺度误差模型;利用确立的尺度之间的递归关系,给出了一种新的多尺度递归数据融合估计算法,在最细尺度上获得了状态基于全局信息的融合估计值;理论推理证明了这种方法的正确性,计算机仿真验证了算法的有效性。     

An adaptive hybrid memetic algorithm for thermal-aware non-slicing VLSI floorplanning

Floorplanning is a crucial step in very large scale integration design flow. It provides valuable insights into the hardware decisions and estimates a floorplan with different cost metrics. In this paper, to handle a multi-objective thermal-aware non-slicing floorplanning optimization problem efficiently, an adaptive hybrid memetic algorithm is presented to optimize the area, the total wirelength, the maximum temperature and the average temperature of a chip. In the proposed algorithm, a genetic search algorithm is used as a global search method to explore the search space as much as possible, and a modified simulated annealing search algorithm is used as a local search method to exploit information in the search region. The global exploration and local exploitation are balanced by a death probability strategy. In this strategy, according to the natural mechanisms, each individual in the population is endowed with an actual age and a dynamic survival age. Experimental results on the standard tested benchmarks show that the proposed algorithm is efficient to obtain floorplans, with decreasing the average and the peak temperature.     

Retaining local image information in gamut mapping algorithms.

Our topic is the potential of combining global gamut mapping with spatial methods to retain the percepted local image information in gamut mapping algorithms. The main goal is to recover the original local contrast between neighboring pixels in addition to the usual optimization of preserving lightness, saturation, and global contrast. Special emphasis is placed on avoiding artifacts introduced by the gamut mapping algorithm itself. We present an unsharp masking technique based on an edge-preserving smoothing algorithm allowing to avoid halo artifacts. The good performance of the presented approach is verified by a psycho-visual experiment using newspaper printing as a representative of a small destination gamut application. Furthermore, the improved mapping properties are documented with local mapping histograms.     

基于模糊增强信息的图像边缘检测改进算法

针对经典的Pal和King模糊增强算法存在的固有缺陷,提出改进的模糊增强算法;为增强图像的对比度而获取更多的图像边缘细节信息,提出基于模糊对比度的图像增强算法;结合全局模糊增强与局部模糊对比度增强两种算法思想,提出基于模糊增强信息的图像边缘检测改进算法,由于该算法在增强图像边缘细节信息的同时也增强了噪声,因此,采用中值平滑滤波方法消除噪声.实验证明,该算法取得了良好的边缘检测效果.     

一种新的快速立体视觉导航算法

立体视觉技术被广泛的应用于视觉导航系统中.由于要求计算快速,以往的立体视觉导航系统通常采用局部匹配的方法,其匹配精确度较差,不能满足高性能视觉导航的需要.为此,我们提出了一种新的快速立体视觉匹配算法,该算法将每一条外极线分割成亮度一致的线段,并采用全局的树型动态规划进行优化求解,既充分利用了全图的相关信息,取得了较高的匹配准确度,又减少了搜索变量的个数,使得系统的效率得到大幅度的提高.实验结果表明,该算法能够取得与基于MRF的全局网格匹配算法相当的匹配结果,而执行时间上却很快,为视觉导航提供了可靠的环境三维数据.