基于特征空间优化的随机森林算法在GF-2影像湿地分类中的研究  

The Random Forest Classification of Wetland from GF-2 Imagery Based on the Optimized Feature Space

作　　者：詹国旗 杨国东[1] 王凤艳[1] 辛秀文 国策 赵强[1] ZHAN Guoqi;YANG Guodong;WANG Fengyan;XIN Xiuwen;GUO Ce;ZHAO Qiang(College of Geo-exploration Science and Technology,Jilin University,Changchun 130012,China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130012

出　　处：《地球信息科学学报》2018年第10期1520-1528,共9页Journal of Geo-information Science

基　　金：国家自然科学基金项目(41472243)~~

摘　　要：由于季节性的植被动态和水文波动,湿地遥感影像分类常常比较困难。本文采用优化特征空间的随机森林算法(Random Forest)对吉林省白城市通榆县东部地区预处理后的GF-2影像进行湿地分类研究,具体分为2步:(1)对研究区遥感影像进行多尺度分割和对象特征的提取。针对一些学者获取最佳分割尺度时仍受主观因素影响较大的情况,本文通过改进全局最优分割方法来获得最佳分割尺度。(2)在最优分割的基础上,基于特征重要性对随机森林分类算法的特征空间进行优化,以得到最佳的随机森林分类结果,并与相同条件下(同数据、同分割尺度、同训练样本,同特征空间)的K-NN、SVM、CART 3种算法以及未优化特征空间的RF算法的分类结果进行了比较。结果表明,基于优化特征空间的RF算法的分类结果总精度和Kappa系数分别为93.038%和0.9177,而K-NN、SVM和CART 3种分类算法的分类结果的总精度分别为83.357%、78.068%、77.136%,未优化特征空间的RF算法分类结果总精度为90.937%。相较于K-NN、SVM、CART 3种分类算法,RF算法在GF-2湿地影像数据中具有更好的分类性能,同时优化特征空间的RF算法精度有所提高,在湿地资源管理中可以发挥非常重要的作用。Due to seasonal vegetation dynamics and hydrological fluctuations, classification of wetland from remote sensing images is often more difficult. In this paper, a pretreated GF-2 image in the east of Tongyu Country, Baicheng City, Jilin Province, was analyzed by Random Forest with optimized feature space. The key method is divided into two steps. The first step is to perform multi-scale segmentation and extraction of object features in the remote sensing image of the study area. For a situation that some scholars obtain the best segmentation scale subjected to subjective factors, this paper obtains the best segmentation scale by improving the global optimal segmentation method, The second step is based on optimal segmentation, to optimize the feature space of the random forest classification algorithm on the basis of the importance of features to obtain the best random forest classification results, and then the classification results of the K-NN, SVM, and CART algorithms with the same data, the same segmentation scale, the same training sample and the same feature space, and the RF algorithm with unoptimized feature space are compared. The results show that the total classification accuracy and Kappa coefficient of the RF algorithm based on optimized feature space are 93.038%and 0.9177, respectively, while the total accuracy of the classification results of K-NN, SVM and CART are83.357% and 78.068%, respectively, 77.136%, the total accuracy of the classification results of RF algorithm with unoptimized feature space is 90.937%. Compared with K-NN, SVM and CART classification algorithms,the RF algorithm has better classification performance in GF-2 wetland image data. At the same time, the accuracy of the RF algorithm with the optimized feature space has been improved, and it can play a very important role in wetland resource management.

关 键 词：GF-2影像 面向对象 随机森林 湿地分类 最优分割尺度 特征空间优化 

分 类 号：X87[环境科学与工程—环境工程] TP751[自动化与计算机技术—检测技术与自动化装置]