基于高光谱成像技术的土壤水分机理研究及模型建立

发布时间：2018-06-04 09:24

本文选题：高光谱成像 + 土壤　；参考：《发光学报》2017年10期

【摘要】：为了研究宁夏地区土壤的水分迁移机理以及对土壤水分快速无损检测,利用高光谱成像(光谱范围900~1 700 nm)技术对土壤的含水率进行了研究。通过高光谱成像系统采集了208个土样,比较了不同天数下土壤含水率与光谱的变化、不同质量含水量光谱的差异。对采集到的土样进行PLSR模型建立,对比分析不同光谱预处理方法、不同方法提取特征波长(UVE、CARS、β系数、SPA)、不同建模方法(MLR、PCR、PLSR)建立的模型,优选出最佳模型。结果表明:在一定的土壤含水量范围内,光谱曲线的反射率与土壤含水率成反比;当增大到超过田间持水率时,光谱曲线的反射率与土壤含水率成正比。对比分析了不同预处理方法,优选出单位向量归一化预处理方法。对比不同的模型,优选出SPA提取的特征波长的MLR模型。最优的特征波长为987,1 386,1 466,1 568,1 636,1 645 nm,最优模型的预测相关系数Rp=0.984,预测均方根误差RMSEP为0.631。因此,今后可采用不同波段对土壤含水率进行定量分析。
[Abstract]:In order to study the mechanism of soil moisture migration and the rapid nondestructive detection of soil moisture in Ningxia region, the soil moisture content was studied by hyperspectral imaging (spectral range 900 ~ 1 700 nm). 208 soil samples were collected by hyperspectral imaging system. The variation of soil moisture content and spectrum and the spectral difference of soil moisture content in different days were compared. The PLSR model of the collected soil samples was established, and the models established by different spectral pretreatment methods, different methods of extracting characteristic wavelength UVECARSs, 尾 coefficient SPAS and different modeling methods were compared and analyzed, and the best model was selected. The results showed that the reflectivity of the spectral curve was inversely proportional to the soil moisture content in a certain range of soil water content, and the reflectivity of the spectral curve was in direct proportion to the soil moisture content when the soil moisture retention rate was increased to a certain extent. Different preprocessing methods are analyzed, and the unit vector normalization preprocessing method is selected. Compared with different models, the MLR model of characteristic wavelength extracted by SPA was selected. The optimum characteristic wavelength is 987 ~ 1386 ~ 1 466N ~ (1 568) ~ 1 636 ~ 1 645 nm, the prediction correlation coefficient of the optimal model is 0.984, and the root mean square error (RMSEP) of the prediction is 0.631nm. Therefore, quantitative analysis of soil moisture can be carried out in different bands in the future.
【作者单位】：宁夏大学土木水利工程学院;宁夏大学农学院;GraduateSchoolofScienceandTechnologyinNiigataUniversityNiigata950-2181;
【基金】：国家自然科学基金(31560481,31060233) 2011年度宁夏回族自治区科技攻关计划(2011HZF05J01) 国家科技支撑计划(2012BAF07B06)资助项目~~
【分类号】：O657.3;S152.7

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