一种端元可变的混合像元分解方法

混合像元线性分解是高光谱影像处理的常用方法，它使用相同的端元矩阵对像元进行分解，其结果是分解精度不高。为此提出了一种端元可变的混合像元分解方法，在确定端元矩阵时，首先考察混合像元与端元的光谱相似性，结合地物空间分布特点，实现了可变端元的混合像元分解。试验结果表明，该分解方法分解精度优于传统线性模型，符合实际情况。     

基于改进SAM的高光谱影像混合像元分解算法研究

将传统遥感图像分类方法中的光谱角度制图法(Spectral Angle Mapping-SAM)加以变换,改进为一种符合全约束条件下的高光谱遥感图像的混合像元分解模型.新算法在端元丰度比例满足全约束的条件下,通过逼近的方法寻找一种端元丰度的比例组合,使测试光谱与目标光谱的广义夹角最小,从而认为该比例组合就是混合像元分解...     

端元约束下的高光谱混合像元非负矩阵分解

提出一种端元约束条件下的非负矩阵分解方法来自动反演混合像元组分。以端元光谱之间的差距为约束条件,使得目标函数综合了影像的分解误差和端元光谱的影响,并以最大后验概率方法导出了限制性非负矩阵分解的迭代算法。成像光谱数据实验结果表明该方法能够自动提取影像的端元光谱矩阵与组分信息,且分解精度比IEA方法高。     

多端元光谱混合分析综述

多端元光谱混合分析是一种端元可变的线性光谱混合分析方法,通过由不同种类和数量的纯净像元(端元)构成的端元组合,对混合像元进行分解。针对每类地物,该方法可以采用多条同种端元光谱进行解混,在一定程度上克服了同种地物的光谱变异问题,能够提高解混的精度。本文对多端元光谱混合分析的具体方法进行综述。首先,基于对多端元解混研究现状的深入分析,归纳了多端元光谱混合分析的基本流程。其次,对多端元解混涉及的端元选取方法进行总结,分别概述了图像端元和参考端元扩充的策略及优化的指标;在此基础上,系统论述了端元光谱库构建主要途径及其优缺点,并指出针对特定的研究区域最佳端元模型确定的方法。最后,提出多端元光谱混合分析存在的问题并给出相应的解决方案。     

非监督正交子空间投影的高光谱混合像元自动分解

利用混合像元线性分解技术处理高光谱影像，以获取研究区域中同一像元的不同组份是遥感应用的主要目的之一。近年来，研究者们发展了一种正交子空间投影技术(0SP)，用来探测感兴趣目标，进一步可以用来分解混合像元，然而应用这种方法分解混合像元的缺陷是需要有研究区域的先验信息，这就制约了它在这方面的应用。为此针对这种不足，提出一种非监督的正交子空间投影(UOSP)技术，用来自动获取影像端元光谱，同时进行混合像元分解。并用成像光谱数据(PHI)实例测试了这个方法，结果表明该方法自动获取的端元比较合理，且分解混合像元精度较高。     

基于修正MCMC的端元可变的混合像元分解算法

传统的混合像元分解一般是基于固定端元的,然而实际上影像中像元并非都由完全相同的端元组成。基于波谱库,将端元选取和丰度反演合为一个步骤,抽象成一个估计参数的随机过程,在端元数目可变的前提下,基于可逆的跳跃式MCMC方法估计参数,从波谱库中选取端元并对混合像元进行线性解混。在状态转移过程中,加入端元的累积知识,以提高算法效率。这种算法不需要人工干预,能够实现自动化像元分解,并且具有较高的精度。实验表明,基于修正MCMC的端元可变的自动化解混算法在分解精度和稳定性方面均优于基于固定端元的混合像元分解方法。     

基于自组织映射和模糊隶属度的混合像元分解

遥感图像中普遍存在着混合像元,将混合像元分解为端元和它们之间混合的丰度,对于高精度的地物识别和定量遥感具有重要意义.结合自组织映射神经网络和模糊理论中的模糊隶属度,提出一种新的多光谱和高光谱遥感图像混合像元分解的方法.首先对自组织映射神经网络进行有监督的训练,然后基于模糊模型对混合像元进行分解.其分解结果自动满足混合像元分解问题所要求的2个约束:丰度值非负约束及丰度值和为1约束.实验结果表明,该方法不仅适用于线性光谱混合的情况,也适用于非线性光谱混合的情况,能够获得较好的混合像元分解结果,同时具有较强的抗噪声能力.     

基于混合像元分解的喀斯特石漠化地物丰度估测

我国西南喀斯特地区长期存在以石漠化为特征的土地退化问题,是我国三大生态问题之一。喀斯特地区地表复杂度高,具有高度时空异质性,像元混合现象严重,植被、裸岩和裸土为喀斯特地区典型地物,使得评价喀斯特石漠化的关键指标(如裸岩率、植被覆盖度)获取比较困难,高光谱遥感在混合像元分解方面有独特优势,可以获取地物端元的丰度。通过地面试验表明光谱指数能够表征地物覆盖度,进而以Hyperion高光谱影像为数据源,利用连续最大角凸锥方法从影像中提取这3类地物的端元,运用半约束和全约束线性光谱分解方法估算其丰度。研究表明:半约束线性分解得到的丰度优于全约束分解结果,其反演的植被、裸土和裸岩的丰度与相应的光谱指数间具有显著线性相关性,确定系数R²分别为0.92、0.66与0.84,表明地物丰度能够表征其覆盖度。因此,通过混合像元分解算法反演地物丰度来提取喀斯特石漠化因子具有一定的可行性,这为高光谱遥感在喀斯特石漠化中的评价和监测奠定了理论和算法基础。     

基于异常探测的高光谱端元提取方法研究

端元提取是高光谱影像分析重要且具有挑战性的任务,是解决高光谱图像混合像元分解关键的步骤。现行的高光谱端元提取算法在端元提取过程中,异常像元同时加入到端元数组中,如何有效区分异常与端元,成为高光谱遥感端元提取的瓶颈,也是提高高光谱图像混合像元分解精度的关键因素。提出一种基于异常探测的高光谱端元提取方法,首先利用RX算法对原始影像进行异常探测,根据异常探测的结果剔除一定数量的像元,将剔除的像元用原始图像均值向量替代,再对影像进行正交子空间投影(OSP)提取端元。实验表明,该方法能够有效区分异常与端元,抑制异常像元参与端元提取,同时处理后的图像端元提取的结果受异常处理的影响很小,证明了去除异常信息后提取端元的可行性。     

端元光谱变化与混合像元分解精度的关系研究

从误差传播理论的角度,分析了多选端元光谱、漏选端元光谱以及端元内部光谱变化等情况与混合像元分解精度之间的关系。然后用数值模拟的方式进一步研究了端元内部光谱与限定性混合像元分解精度的关系。研究结果表明:(1)端元光谱间差距越大,端元光谱内差距越小,则混合像元分解精度越高;(2)如果漏选了端元光谱会造成很大的模型误差,然而多选端元光谱却仍然是端元组分的无偏估计。数值模拟结果表明混合像元分解精度与端元类内变化的方差存在负相关的特点。最后就理论推导的结论,讨论了提高混合像元分解精度的可能方法。     

基于离散粒子群算法的应急物资调度系统研究

应急物资的调度是一个非常重要而实际的研究课题,首要条件是时间最短,在时间最短的基础上要求费用最低。在此基础上,建立了时间最短、成本最低的多目标带约束的数学模型,并利用理想点法将此多目标问题转化为单目标问题,而后利用粒子群算法中的罚函数法将此蒂约束的问题转化为不带约束的问题,最后用离散的粒子群算法求解。实验表明,用粒子群算法求解应急物资调度问题有效可行。     

基于变量转换的并行优化算法

针对大规模边界约束优化问题,现有并行变量转换(PVT)算法不适于直接求解。基于此,采用内点法和逐步下降的思想,提出一个并行求解边界约束最优化问题的可行算法。在下降方向满足梯度相关、步长满足Goldstein规则的条件下,证明该算法的收敛性。当约束失效时,该算法退化为求解无约束的PVT算法,从而成为原有算法向约束优化问题的一个推广。     

多班级交互式教学优化算法

针对教学优化算法（Teaching-Learning-Based Optimization,TLBO）寻优精度低、稳定性差的问题,提出多班级交互式教学优化算法（Multi-Classes Interaction TLBO,MCITLBO）。通过引入基于欧氏距离的新型聚类划分方法,实现多班级教学,加强优秀个体周围邻域的搜索,保证算法具有较好的平衡和局部搜索能力,通过引入两种新的学习方式,实现学习方式多样化,加强种群信息交互、避免子群“滞后”或“早熟”。对6个无约束、4个约束函数和优化拉压弹簧设计问题的数值实验表明,MCITLBO相比其他算法在寻优精度和稳定性上更具优势。     

Estimation of yellow starthistle abundance through CASI-2 hyperspectral imagery using linear spectral mixture models

The invasive weed yellow starthistle (Centaurea solstitialis) has infested between 4 and 6 million hectares in California. It often forms dense infestations and rapidly depletes soil moisture, preventing the establishment of other species. Precise assessment of its canopy cover, especially low-density abundance in the earlier growing season, is the key to effective management. Compact Airborne Spectrographic Imager 2 (CASI-2) hyperspectral imagery was acquired at the western edge of California's Central Valley grasslands on July 15, 2003. Four linear spectral mixture models (LSMM) were investigated from the original CASI-2 data. Band selections based upon residual analysis and feature extraction (PCA) were further explored to reduce the data dimension. All approaches, except four band-selection unconstrained LSMMs, provide consistent results. The uncertainty of the PCA-based LSMM was estimated through a Monte-Carlo simulation. The maximum standard deviation was approximately 11%. The results suggest that unmixing CASI-2 imagery could be used for estimating and mapping yellow starthistle for larger regional areas.     

A modified augmented Lagrangian with improved grey wolf optimization to constrained optimization problems

This paper presents a novel constrained optimization algorithm named MAL-IGWO, which integrates the benefit of the improved grey wolf optimization (IGWO) capability for discovering the global optimum with the modified augmented Lagrangian (MAL) multiplier method to handle constraints. In the proposed MAL-IGWO algorithm, the MAL method effectively converts a constrained problem into an unconstrained problem and the IGWO algorithm is applied to deal with the unconstrained problem. This algorithm is tested on 24 well-known benchmark problems and 3 engineering applications, and compared with other state-of-the-art algorithms. Experimental results demonstrate that the proposed algorithm shows better performance in comparison to other approaches.

     

基于聚类的NSGA-II算法

采用精英策略的非支配排序遗传算法（NSGA-II）种群收敛分布不均匀,全局搜索能力较弱。针对该问题,基于现有的算法,提出一种基于聚类学习机制的多目标进化算法KMCNSGA—II。利用K均值聚类对目标函数和个体分别进行聚类,对聚类后的个体进行局部学习,以提高适应度。将该算法应用于经典的多目标约束和非约束测试函数中,通过收敛性指标世代距离和多样性指标△进行性能评价。实验结果表明,与NSGA—II算法相比,该算法在算法收敛性和种群多样性保持方面均有明显提高。     

Genetic reinforcement learning through symbiotic evolution forfuzzy controller design

An efficient genetic reinforcement learning algorithm for designing fuzzy controllers is proposed in this paper. The genetic algorithm (GA) adopted in this paper is based upon symbiotic evolution which, when applied to fuzzy controller design, complements the local mapping property of a fuzzy rule. Using this Symbiotic-Evolution-based Fuzzy Controller (SEFC) design method, the number of control trials, as well as consumed CPU time, are considerably reduced when compared to traditional GA-based fuzzy controller design methods and other types of genetic reinforcement learning schemes. Moreover, unlike traditional fuzzy controllers, which partition the input space into a grid, SEFC partitions the input space in a flexible way, thus creating fewer fuzzy rules. In SEFC, different types of fuzzy rules whose consequent parts are singletons, fuzzy sets, or linear equations (TSK-type fuzzy rules) are allowed. Further, the free parameters (e.g., centers and widths of membership functions) and fuzzy rules are all tuned automatically. For the TSK-type fuzzy rule especially, which put the proposed learning algorithm in use, only the significant input variables are selected to participate in the consequent of a rule. The proposed SEFC design method has been applied to different simulated control problems, including the cart-pole balancing system, a magnetic levitation system, and a water bath temperature control system. The proposed SEFC has been verified to be efficient and superior from these control problems, and from comparisons with some traditional GA-based fuzzy systems.     

三种训练光滑支持向量分类器方法的比较

光滑支持向量分类机（SSVC）是支持向量分类机（SVC）的快速求解模型,本质上是求解数学规划中具有光滑性和强凸性的无约束最优化问题。BFGS-Armijo和Newton-Armijo算法被用来训练SSVC,相比而言后者拥有更快的训练速度;牛顿-预优共轭梯度法（Newton-PCG）适用于求解无约束的最优化问题,理论上快于一般的Newton类算法。使用Newton-Armijo、BFGS-Armijo和Newton-PCG三种算法来训练光滑支持向量分类机,根据数值实验结果进行分析比较,证明了Newton-PCG算法有更优的效果。     

Constrained least absolute deviation neural networks.

It is well known that least absolute deviation (LAD) criterion or L(1)-norm used for estimation of parameters is characterized by robustness, i.e., the estimated parameters are totally resistant (insensitive) to large changes in the sampled data. This is an extremely useful feature, especially, when the sampled data are known to be contaminated by occasionally occurring outliers or by spiky noise. In our previous works, we have proposed the least absolute deviation neural network (LADNN) to solve unconstrained LAD problems. The theoretical proofs and numerical simulations have shown that the LADNN is Lyapunov-stable and it can globally converge to the exact solution to a given unconstrained LAD problem. We have also demonstrated its excellent application value in time-delay estimation. More generally, a practical LAD application problem may contain some linear constraints, such as a set of equalities and/or inequalities, which is called constrained LAD problem, whereas the unconstrained LAD can be considered as a special form of the constrained LAD. In this paper, we present a new neural network called constrained least absolute deviation neural network (CLADNN) to solve general constrained LAD problems. Theoretical proofs and numerical simulations demonstrate that the proposed CLADNN is Lyapunov stable and globally converges to the exact solution to a given constrained LAD problem, independent of initial values. The numerical simulations have also illustrated that the proposed CLADNN can be used to robustly estimate parameters for nonlinear curve fitting, which is extensively used in signal and image processing.     

关于切换回归的集成模糊聚类算法 GFC

已经有多个方法可用于解决切换回归问题.根据所提出的基于Newton引力定理的引力聚类算法GC,结合模糊聚类算法,进一步提出了新的集成模糊聚类算法 GFC.理论分析表明GFC 能收敛到局部最小.实验结果表明GFC在解决切换回归问题时,比标准模糊聚类算法更有效,特别在收敛速度方面.