【作者】 伍小明；

【导师】 厉小润；

【作者基本信息】 浙江大学 ， 控制理论与控制工程， 2011， 硕士

【摘要】 高光谱遥感影像以其光谱分辨率高、成像波段多的优势(0.4μm-2.5μm),丰富了光谱信息同时也提高了光谱解混能力。由于受到遥感器空间分辨力限制和自然界地物的复杂多样性影响,遥感影像中存在大量的混合像元。高光谱解混能利用高光谱遥感提供的上百个波段图像数据,进入像元内部挖掘图像中的亚像元级信息,提高地物分类和目标探测及识别的精度,为微小地物或者异常地物的探测提供了一个研究途径。高光谱遥感混合像元分解方法主要分为两大类：基于线性模型的解混算法和基于非线性模型的解混算法。本论文主要研究基于核方法的高光谱混合像元非线性解混技术及应用。在系统分析传统的光谱解混理论基础上,本文重点研究运用核方法将传统的基于线性光谱混合模型的解混算法推广到非线性特征空间,解决非线性光谱解混问题。论文的主要工作如下：(1)正交子空间投影(orthogonal subspace projection, OSP)作为传统的监督解混算法,其突出的特点在于提取端元和丰度时,能消除背景信息的影响,同时也可以抑制图像数据噪声的干扰。该算法是在最小均方误差意义上的一种最优化的压缩投影方法。本文这部分工作主要对其非线性推广的理论进行分析验证。该方法不仅揭示了典型地物光谱之间的高阶特性,同时对噪声影响具有较强的鲁棒性。(2)针对现有的非负矩阵分解(nonnegative matrix factorization, NMF)算法,本文给出了一种基于核的非负矩阵方法,并就图像本身是否存在纯像元将其分为(pure pixels kernel based nonnegative matrix factorization, pKNMF)算法和(null pixels kernel based nonnegative matrix factorization, npKNMF)算法。该方法对传统的NMF方法进行非线性映射,运用核函数理论,对输入空间数据点积运算进行核转化,解决了寻找具体非线性映射函数的难题。仿真实验结果和实际遥感数据实验均证明了该算法是有效的。(3)利用高光谱数据端元空间分布的连续性,本文结合端元空间复杂度的思想,提出了基于核方法的空间复杂度非负矩阵分解算法。该方法实现了非线性混合下的像元分解的目的,通过核技巧,对高维特征空间中的映射数据进行高阶特征提取,提高了光谱解混的精度。更多还原

【Abstract】 Hyperspectral remote sensing images can provide enough information for spectral unmixing, owing to its high spectral resolution and hundreds of spectral channels ranging from 0.4 to 2.5 micrometers. However, the modern spectrometer could not bring us to the same high spatial resolution, so the mixed pixels are widespread in hyperspectral imagery. It can improve the precision of imagery classification and target detection by use of the decomposition of the subpixels in the hundreds of imagery data. It is a good research direction for the detection and analysis of the micro-scale and anomaly objection. There are two main hyperspectral unmixing methods that include linear-based and nonlinear-based algorithms. Recently, many scholars develop kinds of new methods in the area of hyperspectral decomposition. The dissertation mainly studies the kernel-based hyperspectral imagery nonlinear umixing techniques and applications. By systematically analysing the traditional spectral decomposition theory, the thesis focuses on extending the algorithms based on linear spectral model to nonlinear feature space in terms of the kernel functions for resolving the difficulties of hyperspectral nonlinear unmixing problem.The major works and contribution of this dissertation are as follows:(1) The orthogonal subspcace projection approach is an traditional supervised unmixing method. It can suppress undesired or interfering spectral signatures, and detect the presence of a spectral signature of interest. This operation is an optimal interference suppression process in the least squares sense. In our thesis, we extend it to nonlinear space to exploit the high order features between the spectral data, and get better robust performance.(2) We extend the traditional nonnegtive matrix factorization method to nonlinear space, and then get a kernel-based nonnegative matrix factorization method that includes pure pixels kernel NMF and null pure pixels kernel NMF. It is a nonlinear version of NMF by using the kernel function to transform the dot product without any knowledge of the nonlinear mapping function. The simulated data and the real hyperspectral imagery experiments show that the methods can provide good performance.(3) According to the spatial continuity of the spectral abundances, we develop a kernel spatial complexity-based nonnegative matrix factorization by incorporating the spatial complexity into a nonlinear version of NMF method. We realize the nonlinear decomposition of hyperspectral imagery via kernel methods. It can improve the performance of the spectral umixing by exploiting the high order features in the high-dimensional feature space.更多还原