基于Sentinel-2 MSI影像与面向对象相结合的红树林树种精细化分类方法研究  

Study on the refined classification method of mangrove tree species based on Sentinel-2 MSI images combined with object-oriented

作　　者：赵阳 李尉尉[1,2] 田震 薛志泳 朱建华 ZHAO Yang;LI Weiwei;TIAN Zhen;XUE Zhiyong;ZHU Jianhua(National Ocean Technology Center,Tianjin 300112,China;Key Laboratory of Ocean Observation Technology,MNR,Tianjin 300112,China)

机构地区：[1]国家海洋技术中心,天津300112 [2]自然资源部海洋观测技术重点实验室,天津300112

出　　处：《Marine Science Bulletin》2023年第2期43-62,共20页海洋通报（英文版）

基　　金：supported by the fund of Provincial and Ministerial Key Laboratory(No. G6210QT01)

摘　　要：红树林是最为典型的滨海生态系统之一,红树林种间类型的精确识别对于红树林生态系统保护、修复及碳储量评估均具有重要意义。遥感是开展红树林种间类型识别的有效手段,但传统的遥感红树林分类方法多是基于像元开展的,分类结果“椒盐”现象严重且精度还有很大提升空间,因此本研究以东寨港红树林保护区为例,基于Sentinel-2 MSI影像,在传统遥感分类方法的基础上引入图像分割技术,分别构建了面向对象的支持向量机(Support Vector Machine,SVM)和随机森林(Random Forest,RF)分类法,并在此基础上对各模型的分类精度和适用性进行了分析,四个模型对比表明:(1)图像分割技术的引入能有效改善分类结果的“椒盐”现象,提升红树林种间类型的识别精度,基于像元使用SVM和RF分类算法总体分类精度为78.82%(Kappa=0.75)、82.94%(Kappa=0.82),面向对象的SVM和RF模型分类总体精度分别为81.5%(Kappa=0.78)、92.67%(Kappa=0.88),相较于以像元为分类对象的模型而言,后者精度提高了2.68%和7.43%;(2)四个模型从总体分类精度、各树种分类精度、模型稳定性和适用性方面RF算法均优于SVM算法;(3)东寨港红树林分为6类,使用面向对象的随机森林分类,榄李和红海榄精度最高,其次为角果木,秋茄和无瓣海桑,海莲精度最低为86.6%,6类树种分类精度均达85%以上。综上所述,基于面向对象使用随机森林分类算法构建分类模型可以准确识别分类红树林不同树种,为红树林种间精细化分类提供理论和技术支持。Mangroves are one of the most typical coastal ecosystems,and the accurate identification of mangrove interspecies types is of great significance for the conservation,restoration and carbon stock assessment of mangrove ecosystems.Remote sensing is an effective means to identify mangrove interspecies types,but traditional remote sensing methods for mangrove classification are mostly based on image elements,and there is much room for improving the accuracy of the classification results.Therefore,based on Sentinel-2 MSI images,this study introduced image segmentation techniques on the basis of traditional remote sensing classification methods.Object-oriented Support Vector Machine(SVM)and Random Forest(RF)classification methods have been respectively constructed,and the classification accuracy and applicability of each model have been analyzed on this basis.(1)The introduction of image segmentation technology can effectively improve the"salt and pepper"phenomenon of classification results and enhance the recognition accuracy of mangrove interspecies types.The overall classification accuracy of SVM and RF classification algorithms based on image elements was 78.82%(Kappa=0.75)and 82.94%(Kappa=0.82),respectively.In contrast,the overall classification accuracy of object-oriented SVM and RF models was 81.5%(Kappa=0.78)and 92.67%(Kappa=0.88),respectively,representing an improvement of 2.68%and 7.43%compared to the image element-based models;(2)the RF algorithm outperformed the SVM algorithm in terms of overall classification accuracy,classification accuracy of each tree species,model stability,and applicability among the four models;(3)Dongzhaigang mangrove forest was classified into 6 categories,and using the object-oriented random forest classification,the highest precision was achieved for Lumnitzeraracemosa and Rhizophora stylosa,followed by Ceriops tagal,Kandeliaobovata,and Sonneratia apetala,and the lowest precision was 86.6%for Bruguierasexangula,while the precision of all 6 categories reached over 85%.In summary,t

关 键 词：红树林种间分类 多光谱 面向对象 随机森林 支持向量机 

分 类 号：S718.5[农业科学—林学] P237[天文地球—摄影测量与遥感]