王雷光, 耿若筝, 代沁伶, 王军, 郑晨, 付志涛. 高光谱-LiDAR 融合的条件随机场分类方法[J]. 红外与激光工程, 2021, 50(12): 20210112. DOI: 10.3788/IRLA20210112
引用本文: 王雷光, 耿若筝, 代沁伶, 王军, 郑晨, 付志涛. 高光谱-LiDAR 融合的条件随机场分类方法[J]. 红外与激光工程, 2021, 50(12): 20210112. DOI: 10.3788/IRLA20210112
Wang Leiguang, Geng Ruozheng, Dai Qinling, Wang Jun, Zheng Chen, Fu Zhitao. Conditional random field classification method based on hyperspectral-LiDAR fusion[J]. Infrared and Laser Engineering, 2021, 50(12): 20210112. DOI: 10.3788/IRLA20210112
Citation: Wang Leiguang, Geng Ruozheng, Dai Qinling, Wang Jun, Zheng Chen, Fu Zhitao. Conditional random field classification method based on hyperspectral-LiDAR fusion[J]. Infrared and Laser Engineering, 2021, 50(12): 20210112. DOI: 10.3788/IRLA20210112

高光谱-LiDAR 融合的条件随机场分类方法

Conditional random field classification method based on hyperspectral-LiDAR fusion

  • 摘要: 为有效利用高光谱影像与LiDAR数据的互补性信息,解决单一融合策略造成的场景解译地物边界不准确和分类精度低的问题,提出了一种光谱-空间-高度特征融合、并顾及场景地物类别共生特性的条件随机场分类方法。首先,对两种数据分别提取光谱及形态学特征,对特征集采用图模型进行特征融合,将特征输入概率支持向量机分类器,得到初始分类结果。然后,基于融合特征计算反映像素间类别本质差异的局部光谱-空间-高度协同的异质性值,并统计类别间的空间共生关系。最后,在条件随机场框架内,整合初始分类结果、局部异质性信息及类别共生关系,通过目标函数的迭代求解获得最终分类结果。通过将像素间的权重定义为对应像素位置融合特征的归一化欧式距离的单调减函数,对标记不同但特征差异较大的类别间给予较小的权重,以达到地物边界空间规整化的目的。通过对标记不同但共生概率较大的类别对给予较小的权重,达到保留空间关系稳定的类别对的目的。采用城区场景的美国休斯顿地区数据集和林区场景的中国广西高峰林场两组数据集对提出方法进行了验证。实验结果表明:休斯顿和高峰林场数据集精度分别达到94.00%和92.84%,分类结果的“胡椒盐”现象明显减少,证明了该方法的有效性。

     

    Abstract: The interpretation of single remotely sensed data source may suffer from inaccurate boundary and low classification accuracy. The integration of hyperspectral and LiDAR data opens up the possibility to improve the classification performance. But, it is a challenge that how to appropriately integrate the considerable heterogeneity between the two types of data. In this paper, a conditional random field classification method was proposed to solve this problem by jointly taking both the heterogeneity of fused spectral-spatial-height features and co-occurrence of class labels into account. Firstly, the morphological features were extracted from two types of data respectively, and a graph model and training samples were jointly used to fuse the morphological features and spectral features. The obtained features were inputted into a support vector machine classifier to obtain the initial classification results with probabilistic outputs. Then, based on the fusion features, a local heterogeneity value was calculated to measure the essential difference of classes among pixels. Meanwhile, a class co-occurrence matrix, whose element calculated the spatial relationship between classes, was also obtained. Finally, a conditional random field framework was used to integrate the initial classification results, local heterogeneity information and the class co-occurrence matrix, and obtain the final classification results through inferencing two objective functions. In this process, by defining the weight between two neighboring pixel as a monotone decreasing function respect to the normalized Euclidean distance of the corresponding fused features, the object boundary could be regularized by giving a smaller weight to the class pairs with different labels and distinct features. Similarly, by giving a small weight to the class pairs with a strong spatial relationship, the purpose of maintaining the class pairs with stable spatial relations could be achieved. The method was validated with Houston and Gaofeng forest farm data sets. The overall accuracies of the proposed method reached to 94.00% and 92.84% respectively, and the "pepper and salt" phenomena of the initial classification results were significantly reduced. The result indicates the effectiveness of the proposed method.

     

/

返回文章
返回