一种间接从高光谱数据中提取黑土硒含量的新方法  

A New Indirect Extraction Method for Selenium Content in Black Soil from Hyperspectral Data

作　　者：张东辉[1] 赵英俊[1] 赵宁博[1] 秦凯[1] 裴承凯[1] 杨越超 ZHANG Dong-hui;ZHAO Ying-jun;ZHAO Ning-bo;QIN Kai;PEI Cheng-kai;YANG Yue-chao(National Key Laboratory of Remote Sensing Information and Imagery Analyzing Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]核工业北京地质研究院遥感信息与图像分析技术国家级重点实验室

出　　处：《光谱学与光谱分析》2019年第7期2237-2243,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41602333);“十三五”装备预先研究专项技术项目(32101080302);中国地质调查局黑土地航空高光谱遥感调查项目(SYZXW2017101);遥感信息与图像分析技术国家级重点实验室基金项目(6142A0104041611003)资助

摘　　要：我国东北黑土富含养分,随着土壤数字制图、精确农业和土壤资源调查等研究的深入,引入航空高光谱数据并提供科学的预测结果成为研究热点。硒元素相对于黑土土壤的主要成分属于微量元素,但其对作物的正常生长的作用与大量元素是同等重要的,亦是人体健康所必要的营养元素。针对硒含量反演,建立了一个基于主要成分的间接提取模型,该模型能够显著提升硒含量回归系数,降低实测值与预测值的误差。数据源自CASI-1500航空高光谱成像系统,光谱范围380~1050nm,空间分辨率1.5m。在黑龙江建三江地区采集60个土壤样本,化验获得硒、有机质、全铁、pH和氧化钙含量数据,选择BP神经网络,建立光谱与含量的反演模型。分析不同含量的黑土成分在可见-近红波段范围内光谱变换规律,掌握了硒元素随着含量升高,光谱反射率会逐步升高的规律。但当硒含量较低时,在其他成分的干扰下,这一规律会逐渐减弱,直至不显著。有机质的光谱特征与硒元素相反,总体上随着含量的增高,反射率整体下降,这与有机质的光谱特性紧密相关。全铁光谱呈现出与有机质光谱类似的规律,说明二者具有较高的相关性。不同pH值和氧化钙含量的光谱特征与检测值没有呈现出明显的特征规律,反射规律不明显。对60个采样点不同养分含量进行逐波段求反射率对养分的相关系数。结果表明,pH值各个波段相关系数最高,均值达到0.63;其次是全铁的相关系数,为0.54;有机质和氧化钙的相关系数接近,分别为0.42和0.47;而硒元素含量与逐波段的平均相关系数最低,为0.38。选取相关系数较高的前5个波段,作为建模波段。硒特征波段为447,437,456,466和475nm;有机质特征波段为447,456,466,437和475nm;全铁特征波段为752,695,800,762和733nm;pH特征波段为905,752,800,943和695nm;氧化钙特征波段为752,695,800,523和762nm。通过计算样In the field of soil digital mapping, precision agriculture and soil resource investigation, the study of aerial hyperspectral data to provide scientific prediction results by aerial hyperspectral have become the focus of research, especially in the case of black soil rich in nutrients in Northeast China. Compared with the main components of soil in the black soil, selenium is a trace element, whose effect on the normal growth of crops is as important as a large number of elements, and it is also a necessary nutrient element for human. In this paper, an indirect extraction model based on the main component is created for the retrieval of selenium content. This model can significantly increase the regression coefficient of selenium content and reduce the error between the measured value and the predicted value. The data source is CASI-1500 aerial hyperspectral imaging system with a spectral range of 380~1 050 nm, and a spatial resolution of 1.5 m. 60 soil samples were collected from the Jiansanjiang area of Heilongjiang. The data of selenium, organic matter, total iron, pH and calcium oxide content were obtained. The BP neural network was selected to establish the inversion model of spectrum and content. In addition, the law of spectral change in the visible and near infrared range of different content of black soil composition was analyzed, and the rule that the spectral reflectance would increase gradually as the content of selenium increased. However, when the selenium content was low, the law would gradually weaken until the other components are disturbed. The spectral characteristics of organic matter were opposite to that of selenium. In general, the reflectance decreases as the content increases, which is closely related to the spectral properties of organic matter. The spectra of the total iron showed similar laws with the organic matter spectrum, indicating that the two have high correlation. The spectral characteristics and detection values of different pH values and calcium oxide contents did not show o

关 键 词：硒含量 东北黑土地 航空高光谱 神经网络 可见光-近红外 

分 类 号：O433.4[机械工程—光学工程]