中国农业科学 ›› 2018, Vol. 51 ›› Issue (8): 1464-1474.doi: 10.3864/j.issn.0578-1752.2018.08.004

• 耕作栽培·生理生化·农业信息技术 • 上一篇    下一篇

一款无人机高光谱传感器的验证及其在玉米叶面积指数反演中的应用

陈鹏飞1,2,李刚3,石雅娇1,徐志涛1,4,杨粉团3,曹庆军3

 
  

  1. 1中国科学院地理科学与资源研究所/资源与环境信息系统国家重点实验室,北京100101;2白洋淀流域生态保护与京津冀可持续发展协同创新中心,河北保定 0710023吉林省农业科学院,长春 130033;4东华理工大学测绘工程学院,南昌 330000
  • 收稿日期:2017-10-12 出版日期:2018-04-16 发布日期:2018-04-16
  • 作者简介:陈鹏飞,E-mail:pengfeichen@igsnrr.ac.cn
  • 基金资助:
    国家重点研发计划项目(2017YFD02015,2017YFD0201501-05)、国家科技基础性工作专项(2014FY210100)

Validation of an Unmanned Aerial Vehicle Hyperspectral Sensor and Its Application in Maize Leaf Area Index Estimation

HEN PengFei1,2, LI Gang3, SHI YaJiao1, XU ZhiTao1,4, YANG FenTuan3, CAO QingJun3   

  1. 1Institute of Geographical Science and Natural Resources Research, Chinese Academy of Sciences/State Key Laboratory of Resources and Environment Information System, Beijing 100101; 2Collaborative Innovation Center for Ecological Protection of Baiyangdian Watershed and Sustainable Development of Beijing, Tianjing and Hebei, Baoding 071002, Hebei; 3Jilin Academy of Agricultural Sciences, Changchun 130033; 4Faculty of Geomatics, East China University of Technology, NanChang 330000
  • Received:2017-10-12 Online:2018-04-16 Published:2018-04-16

摘要: 【目的】验证无人机机载高光谱传感器S185,并基于其获得的影像探讨无人机高光谱遥感反演叶面积指数的新方法。【方法】以东北玉米为研究对象,在吉林省公主岭市开展了玉米氮肥梯度试验,共设5处理,每个处理3次重复。分别在玉米的V5—V6,V11,R1—R2等生育期(Ritchie生育期)进行无人机飞行试验和地面光谱及叶面积指数测定,共获得数据45组。为验证S185影像数据,在相同尺度下提取S185影像信息与地面光谱信息,一方面从测定同一目标地物两者光谱反射率间的相关性进行分析,另一方面筛选15种常用的各类光谱指数,从整个生育期通过影像数据计算的各光谱指值与地面光谱仪计算的相应值变化趋势的一致性进行分析;将45组样品随机选择30组,基于人工神经网络算法利用S185数据建立反演叶面积指数的模型,剩下15组样品作为外部验证样品,用来验证神经网络模型的预测效果。另外,基于相同的分组数据,利用前面筛选的各光谱指数分别建立叶面积指数的反演模型,以与人工神经网络建模结果进行比较。【结果】在各个生育时期,同种目标地物S185测定数据与地面光谱仪测定数据间具有很强的相关性,相关系数在0.99以上;在玉米整个生育期,S185数据计算的各光谱指数与地面光谱仪计算的各光谱指数变化趋势相同,相关系数在0.88以上;在构建基于人工神经网络法反演叶面积指数的模型中,建模时的决定系数为0.96,均方根误差为0.42,相对均方根误差为13.15%;外部验证时的决定系数为0.95,均方根误差为0.54,相对均方根误差为16.74%,这一结果优于基于各光谱指数建立的叶面积指数反演模型。【结论】无人机搭载S185传感器可用于准确获取玉米冠层高光谱信息,且可利用人工神经网络法基于这一数据建立玉米叶面积指数的反演模型。

关键词: 无人机, 高光谱, 叶面积指数, 玉米, S185

Abstract: 【Objective】 The objective of this study is to validate the unmanned aerial vehicle (UAV) hyperspectral sensor S185, and then to design a new method for maize leaf area index (LAI) estimation based on its collected image. 【Method】 Taking maize in northeastern China as study material, nitrogen fertilizer experiment was conducted in Gongzhuling city in Jilin province. In the experiment, five nitrogen treatments and three replications were applied. The UAV flight experiment, the ground spectrum and LAI were measured at V5-V6, V11, R1-R2 growth stage (Ritchie growth stage) of maize. At last, 45 groups of data were collected. To validate images from hyperspectral sensor S185, the spectra from S185 image and from ground spectral device were extracted and compared in the same scale. On the one hand, the correlation analysis was taken to analysis the relationship between S185 data and ground measured spectra, which were from the same target; On the other hand, 15 commonly used spectral indices were selected, and then they were calculated from S185 date and from the ground spectra, respectively, and at last, the relationship between them during the whole maize growth stage was analyzed to show their change trend consistency. 30 groups of data were randomly selected from the collected 45 groups of data, artificial neural network method (ANN) was used to establish LAI prediction model by using S185 images, and then the remainder 15 groups of data were used to validate the performance of ANN model. In addition, based on the same calibration and validation dataset, LAI prediction models were designed by using each selected spectral index individually in order to compare with ANN LAI prediction model. 【Result】 In each maize growth stage, S185 spectra had a high relationship with corresponding spectra measured by ground spectral device for the same target, with correlation coefficients higher than 0.99; in the whole maize growth stage, the calculated spectral indices from the S185 images had a high relationship with the corresponding value calculated from ground measured spectra, with correlation coefficient higher than 0.88; During the design of the ANN prediction model for LAI, the model had an R2 value of 0.96, a RMSE value of 0.42 and a RMSE% value of 13.15% during calibration and had an R2 value of 0.95, an RMSE value of 0.54 and an RMSE% value of 16.74% during external validation. The model performed better than models designed by spectral indices. 【Conclusion】 The results showed S185 can be mounted on UAV to measure maize canopy hyperspectra image accurately, and ANN method can be used to design LAI prediction model based on UAV.

Key words: unmanned aerial vehicle, hyperspectra, leaf area index, maize, S185