光谱技术结合BiPLS-GA-SPA和ELM算法的生菜冠层氮素含量检测研究  

Measurement of Nitrogen Content in Lettuce Canopy Using Spectroscopy Combined with BiPLS-GA-SPA and ELM

作　　者：高洪燕[1] 毛罕平[1] 张晓东[1] 

机构地区：[1]江苏大学现代农业装备与技术教育部重点实验室,江苏镇江212013

出　　处：《光谱学与光谱分析》2016年第2期491-495,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金重点项目(61233006);国家"十二五"科技支撑计划项目(2014BAD08B03);江苏省普通高校研究生科研创新计划项目(CXZZ13_0690);江苏高校优势学科建设工程资助项目(苏政办发[2014]37号)资助

摘　　要：氮素是影响生菜产量和品质的重要因素,光谱技术是检测作物氮素含量最有效的手段之一。通过获取不同氮素水平下生菜冠层的反射光谱,对其进行FDSGF(first-order derivative based savitzky-golay filt)滤波后,利用后向区间偏最小二乘算法(BiPLS)、遗传算法(GA)及连续投影算法(SPA)对特征波长进行梯度提取,最终从2 151个波长点中提取了8个与生菜氮素最为相关的特征波长。分别利用多元线性回归(MLR)、径向基函数神经网络(RBFNN)及极限学习机(ELM)三种算法建立了基于特征波段或特征波长的8个生菜冠层氮素含量检测模型。结果表明:BiPLS-GA-SPA-ELM模型(RMSEC=0.241 6%,Rc=0.934 6,RMSEP=0.284 2%,Rp=0.921 8)的预测结果优于其他模型,为指导合理施肥和开发便携式仪器提供了理论基础。Nitrogen fertilizer is necessary to improve yield and quality of lettuce.Spectroscopy is one of the most effective techniques used to detect crop nitrogen content.In this study,canopy reflectance spectra were acquired under five levels of nitrogen,and then were Savitzky-Golay smoothed,the first-order derivative spectra were calculated from the smoothed spectra to eliminate noise effects.Backward interval partial least squares（BiPLS）,genetic algorithm（GA）and successive projections algorithm（SPA）were combined to select the efficient wavelengths.The number of variables was decreased from 2 151 to 8.The optimal intervals or variables were used to build multivariable linear regression（MLR）model,radial basis function neural network（RBFNN）models and extreme learning machine（ELM）models.This work proved that the results of BiPLS-GA-SPA-ELM model was superior to others with RMSEC was 0.241 6%,Rc was 0.934 6,RMSEP was 0.284 2% and Rpwas 0.921 8.Our research results may provide a foundation for nutrition regulation and developing instrument.

关 键 词：反射光谱 后向区间偏最小二乘 遗传算法 连续投影算法 径向基函数神经网络 极限学习机 

分 类 号：S123[农业科学—农业基础科学] S127