【作者】 孙书进；

【导师】 邹焕新；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2011， 硕士

【摘要】 合成孔径雷达(Synthetic Aperture Radar,SAR)作为一种信息获取手段,在国防、环境等方面具有突出的战略意义。SAR图像地物分类是SAR图像解译的重要内容,基于马尔可夫随机场(Markov Random Field,MRF)和统计建模的SAR图像地物分类方法充分利用了图像中的上下文信息和图像灰度统计分布特征,在图像处理中得到了广泛的应用。本文系统研究了基于MRF和统计建模的SAR图像地物分类方法。首先,作为全文研究的理论基础,深入分析了SAR图像杂波的统计模型。文中全面概括了现有SAR图像杂波统计模型,深入研究了基于Mellin变换的参数估计方法,总结了该参数估计方法在已有分布模型中的参数求解方程。为了满足高分辨率条件下的数据建模需求,文中重点研究分析了一种基于字典集的SAR图像统计建模方法(DSEM)。为了完成多极化SAR数据建模,研究了多通道数据建模工具:copula连接函数。其次,研究了基于MRF模型和统计建模的单极化SAR图像分类方法。文中研究了MRF模型应用于图像分类的理论框架,并结合SAR图像统计建模基础知识,研究了SAR图像分类方法以及求解最优标记矩阵的优化算法。基于copulas理论提出一种首先建立灰度数据空间和对比度纹理数据空间的联合分布,然后基于MRF模型完成单极化图像分类的方法。最后,研究了基于MRF模型和统计建模的多极化SAR图像分类方法。文中研究了基于copulas函数多极化SAR图像统计建模方法,并借鉴字典集的思想提出了一种基于字典集的混合copulas建模方法。实验证实,对于多极化SAR图像统计分布建模,该方法有更好的数据描述能力。同时也验证了,与单极化SAR图像分类相比较,多极化SAR图像分类由于综合利用了多通道数据信息,能够取得更好的分类结果。更多还原

【Abstract】 As a tool of acquiring information, SAR is of significant strategic sense, the interpretation of SAR imagery is a very important task. Terrain classification plays an important part in the interpretation of SAR imagery. The classification method based on MRF model and statistic modeling, which is able to unify the contextual information from label images and statistical properties of observed images, was widely used and developed in image processing. In this thesis, SAR image classification method based on MRF and statistical modeling is thoroughly studied.Firstly, as the foundation theory, SAR clutter statistical model is studied in depth. According to existing work and the progresses made recently, the relevant techniques of statistical modeling of clutter in SAR image are comprehensively reviewed, and a parameter estimation approach stemming from Mellin transform which is also named“Method of Log-Cumulant”(MoLC) is introduced and analyzed in detail. Based on MoLC, the estimate equations of the statistical distribution models mentioned are induced and comprehensively summarized. To satisfy the requirement in the modeling of high-resolution SAR imagery, a recently proposed method named“Dictionary based stochastic expectation maximization for SAR amplitude probability density function”is studied. Copula, a statistical tool that was designed for constructing joint distributions from marginals with a wide variety of allowable dependence structures, is introduced to model the join distribution of multi-channel space of data.Secondly, the classification of single polarized SAR imagery based on MRF model and statistical modeling is studied. Based on MRF model, the process of image classification is turned to be a problem of energy-minimum by seeking the optimal label Matrix. A classification method based on MRF model and the joint distribution of the data space of gray level and texture information (Contrast Statistics) deduced from Gray Level Co-occurrence Matrix (GLCM) via copulas is proposed.Finally, the classification of multi-polarized SAR imagery based on MRF model and statistical modeling is studied. Statistical modeling approach based on copula theory is studied. After the in depth study of finite mixture copulas model, a dictionary based mixture copulas model is proposed, which has good statistical representation ability. Experiments verified the better performance, compared with the classification process only using single-polarized data.更多还原