光学 精密工程, 2010, 18 (3): 586, 网络出版: 2010-08-31
应用近红外漫反射光谱快速测定土壤锌含量
Rapid measurement of zinc contents in soils by near-infrared diffuse reflectance spectroscopy
土壤 锌 近红外漫反射光谱 偏最小二乘法 波段选择 soil Zn near-infrared diffuse reflectance spectroscopy partial least square method wave band choice
摘要
采用近红外漫反射光谱和偏最小二乘法(PLS)建立了土壤锌快速分析的定量模型,并进行了波段优选。首先,基于单波长模型预测效果将全体样品划分为定标集和预测集;然后,采用多元散射校正(MSC)和Savitzky-Golay(SG)平滑方法对光谱进行预处理。选取全谱400~2 500 nm,400~1 100 nm,1 100~1 900 nm,1 900~2 500 nm,580~900 nm等5个波段,每个波段分别采用原谱、一阶导数谱、二阶导数谱,共建立了15个定标模型。同时调整SG平滑点数和PLS因子数,每个模型分别进行PLS数值实验,按照预测效果进行优选。结果显示,采用1 900~2 500 nm波段一阶导数谱的模型效果最好,预测相关系数(RP)、RMSEP、RRMSEP分别为0.806,31.0 mg/kg和19.96%。这些结果表明,1 900~2500 nm波段可以代替全谱波段得到更好的预测效果,可为设计专用土壤近红外光谱仪提供依据。
Abstract
The quantification model of zinc rapid analysis in the soils was established by using near-infrared diffuse reflectance spectroscopy and a Partial Least Square (PLS) method, and the optimal measured wave band was also selected.All the samples were divided into calibration set and prediction set based on the prediction effect of single wavelength model, and then the spectra were pretreated by Multiplicative Scatter Correction (MSC) and Savitzky-Golay (SG) smoothing methods.The following five wave bands, the whole region 400-2 500 nm,400-1 100 nm,1 100-1 900 nm,1 900-2 500 nm,580-900 nm were selected, and 15 calibration models were constructed for each band selected by the original spectra, the first derivative spectra and the second derivative spectra respectively.By simultaneous adjusting the numbers of SG smoothing points and PLS factors,the PLS computational experiments for each model were carried out and the best model was selected according to the prediction effect.The results indicate that the prediction effect of the model using the first derivative spectra in 1 900-2 500 nm is the best, and its prediction correlation coefficient (RP), RMSEP and RRMSEP are 0.806, 31.0 mg/kg, and 19.96% respectively.Obtained results show that 1 900-2 500 nm can replace the whole band to get a better calibration effect, and can provide a basis for the design of special soil near-infrared spectroscopy instruments.
黄富荣, 潘涛, 张甘霖, 潘贤章, 刘登飞. 应用近红外漫反射光谱快速测定土壤锌含量[J]. 光学 精密工程, 2010, 18(3): 586. HUANG Fu-rong, PAN Tao, ZHANG Gan-lin, PAN Xian-zhang, LIU Deng-fei. Rapid measurement of zinc contents in soils by near-infrared diffuse reflectance spectroscopy[J]. Optics and Precision Engineering, 2010, 18(3): 586.