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林业科学 ›› 2018, Vol. 54 ›› Issue (9): 70-79.doi: 10.11707/j.1001-7488.20180909

• 论文与研究报告 • 上一篇    下一篇

基于多源遥感的森林地上生物量KNN-FIFS估测

韩宗涛1,2, 江洪1,4, 王威3, 李增元2, 陈尔学2, 闫敏2, 田昕2   

  1. 1. 福州大学地理空间信息技术国家地方联合工程研究中心 空间数据挖掘与信息共享教育部重点实验室 福州 350002;
    2. 中国林业科学研究院资源信息研究所 北京 100091;
    3. 国家林业和草原局调查规划设计院 北京 100714;
    4. 海西政务大数据应用协同创新中心 福州 350003
  • 收稿日期:2016-12-05 修回日期:2017-06-15 出版日期:2018-09-25 发布日期:2018-09-10
  • 基金资助:
    中央级公益性科研院所基本科研业务费专项资金“森林资源动态变化时空连续监测方法研究”(CAFYBB2017QC005)。

Forest Above-Ground Biomass Estimation Using KNN-FIFS Method Based on Multi-Source Remote Sensing Data

Han Zongtao1,2, Jiang Hong1,4, Wang Wei3, Li Zengyuan2, Chen Erxue2, Yan Min2, Tian Xin2   

  1. 1. Key Laboratory of Spatial Data Mining & Information Sharing of Ministry of Education National Engineering Research Center of Geo-spatial Information Technology, Fuzhou University Fuzhou 350002;
    2. Research Institute of Forest Resource Information Techniques, CAF Beijing 100091;
    3. Academy of Forestry Inventory and Planning, National Forestry and Grassland Administration Beijing 100714;
    4. Fujian Collaborative Innovation Center for Big Data Applications in Governments Fuzhou 350003
  • Received:2016-12-05 Revised:2017-06-15 Online:2018-09-25 Published:2018-09-10

摘要: [目的]针对多源遥感数据及其派生特征因子数据维度高、信息冗余、易造成估测模型过拟合等问题,从高维度遥感特征因子中高效优化特征组合,优化区域森林地上生物量(AGB)的k最近邻(k-NN)估测模型。[方法]提出基于快速迭代特征选择的k最近邻法(KNN-FIFS),以森林资源样地调查数据计算的森林AGB为参考,以留一法交叉验证(LOO)相应的k-NN模型反演的森林AGB均方根误差(RMSE)最小为原则,依次迭代选取遥感特征,优化区域森林AGB的k-NN估测模型。以大兴安岭根河森林保护区为研究区,结合Landsat-8 OLI各波段光谱信息、植被指数、纹理、地形因子、机载合成孔径雷达(SAR) P-波段HV极化后向散射强度信息(PHV)以及森林资源样地调查数据,利用KNN-FIFS方法估测研究区森林AGB,并与多元线性逐步回归法(SMLR)进行对比分析。[结果]利用KNN-FIFS方法,得到当k为3,特征组合为PHV、短波红外波段一均一性(H6)、短波红外波段一二阶矩(S6)、短波红外波段二二阶矩(S7)、海蓝波段相关性(Cr1)、近红外波段相关性(Cr5)、海蓝波段相异性(D1)、增强型植被指数(EVI)时,研究区森林AGB估测结果最优,其精度(R2=0.77,RMSE=22.74 t·hm-2)显著优于SMLR估测精度(R2=0.53,RMSE=32.37 t·hm-2)。[结论]KNN-FIFS方法相比SMLR更适用于森林AGB多源遥感估测;KNN-FIFS方法可以从高维度遥感特征因子中高效选取相关特征进行森林AGB估测。

关键词: KNN-FIFS, 特征选择, 地上生物量

Abstract: [Objective] Aiming at the over-fitting problem caused by information redundancy from multi-source remote sensing data and their derived high-dimensional features, this study is to effectively pre-select the optimal feature combination to optimize the k-nearest neighbor (k-NN) for regional forest above-ground biomass (AGB) estimation.[Method] This study proposed a fast iterative features selection method for k-NN method (KNN-FIFS). This method iteratively pre-select the optimal features which determined by the minimum root mean square error (RMSE) between the measured forest AGB values and the k-NN estimates based on the leave-one-out (LOO) cross-validation. Based on KNN-FIFS, multi-source data, including Landsat-8 OLI and its vegetation indices, texture metrics, topographic factors, HV polarization of P-band synthetic aperture radar (SAR) data, and forest inventory data (PHV), were used to estimate forest AGB over Daxing'an Mountain Genhe forest reserve located in Inner Mongolia. Afterwards, the model behaviors between KNN-FIFS and stepwise multiple linear regression (SMLR) method were compared.[Result] For KNN-FIFS method, the best configuration was that one with k of 3, the remotely sensed features using PHV, second moment of 1st and 2nd short-wave infrared bands (S6,S7), homogeneity of 1st short-wave infrared band (H6), correlation of coastal aerosol (Cr1), correlation of the near infrared (Cr5), dissimilarity of coastal aerosol (D1) and the enhanced vegetation index (EVI). This configuration generated the most accurate estimates with R2=0.77 and RMSE=22.74 t·hm-2,which performed much better than SMLR with R2=0.53 and RMSE=32.37 t·hm-2.[Conclusion] KNN-FIFS is a more suitable method for forest AGB estimation than SMLR. KNN-FIFS can efficiently select the optimal feature combination to estimate regional forest AGB by use of multi-source remote sensing data with high-dimensional information.

Key words: KNN-FIFS, feature selection, above-ground biomass(AGB)

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