摘要
自然农田生态系统中,农作物的各种生化参数受重金属污染胁迫后虽表现异常,但其特征往往极为微弱,极不稳定。利用处理非稳定信号方法中常用的信号处理方法——小波分析法(Db-5),对水稻的光谱反射率数据进行处理,有效提取光谱信号中受重金属污染胁迫而潜藏的一些“突变”弱信息。利用Db-5小波基进行小波变换,从中选取具有异常光谱特征的奇异点,利用奇异点对应波段(716、745、766nm)的光谱反射率构建反向传播(BP)神经网络模型,对水稻冠层4种重金属含量进行反演。将利用模型得到的预测值与实测值进行相关性分析,结果表明,基于BP神经网络的水稻冠层重金属含量反演模型对于实验区镉、铅、汞、砷4种重金属胁迫,具有良好的反演效果。
In the "natural farmland ecosystem ",although the biochemical parameters of crops are abnormal under the stress of heavy metal pollution,their characteristics are often very weak,with small changes and extreme unstability. Wavelet analysis,a common signal processing method in unstable signal processing,was used to process spectral reflectance data of crops( rice) and effectively extract weak information of "mutation"hidden in spectral signals under the stress of heavy metal pollution. Wavelet transform was carried out by using Db-5 wavelet basis,and singular points with abnormal spectral characteristics were selected. Back propagation neural network model( BPNN) was constructed by using spectral reflectance of corresponding bands of singular points( 716 nm,745 nm and 766 nm) to invert the contents of four heavy metals in rice canopy. Correlation analysis was conducted between the predicted and measured values of the model,and the results showed that the inversion model of heavy metal content in rice canopy based on BP neural network had a good inversion effect on the stress of cadmium,lead,mercury and arsenic in the experimental area.
作者
李旭青
李龙
庄连英
刘玮琦
刘湘南
李杰
LI Xuqing;LI Long;ZHUANG Lianying;LIU Weiqi;LIU Xiangnan;LI Jie(Institute of Computer and Remote Sensing Information Technology,North China Institute of Aerospace Engineering,Langfang 065000,China;Aerospace Remote Sensing Information Processing and Application Collaborative Innovation Center of Hebei Province,Langfang 065000,China;School of Information Engineering,China University of Geosciences(Beijing),Beijing 100083,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2019年第6期226-232,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家高分辨率对地观测系统重大专项(67-Y20A07-9002-16/17)
国家自然科学基金项目(41371407)
河北省青年科学基金项目(D2018409029)
河北省高等学校科学技术研究重点项目(ZD2016126)
北华航天工业学院博士基金项目(BKY-2015-02)
河北省航天遥感信息处理与应用协同创新中心开放课题项目(XTZXKF201701)
关键词
小波变换
高光谱
重金属胁迫
农作物污染
反演模型
wavelet transform
hyperspectra
heavy metal stress
crop pollution
inversion model
