铜污染土壤光谱特征及弱差信息的LH-PSD甄测模型  

The LH-PSD Analysis Model of Cu Contaminated Soil Spectral Characteristics and Weak Characteristic Information

作　　者：杨可明 张伟[1] 付萍杰 高鹏[1] 程凤 李燕[1] YANG Ke-ming;ZHANG Wei;FU Ping-jie;GAO Peng;CHENG Feng;LI Yan(State Key Laboratory Coal Resources and Safe Mining,China University of Mining&Technology,Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)煤炭资源与安全开采国家重点实验室

出　　处：《光谱学与光谱分析》2019年第7期2228-2236,共9页Spectroscopy and Spectral Analysis

基　　金：煤炭资源与安全开采国家重点实验室开放基金项目(SKLCRSM17KFA09);国家自然科学基金项目(41271436)资助

摘　　要：土壤受重金属污染后,会影响农作物及食品安全,危及人体健康,因此寻找快速、高效甄测土壤重金属污染信息的方法尤为关键。传统化学分析方法存在过程繁杂、费时耗力等缺点,而高光谱遥感因光谱分辨率高、信息量大、快速无损等特点在环境监测等应用方面优势明显。由于电磁遥感信号反射、辐射过程复杂,通过仪器获取的土壤高光谱数据难以直接解析出重金属污染信息,因而,研究并寻求一种能够有效挖掘土壤重金属污染信息的方法对高光谱遥感监测污染意义重大。不同浓度铜(Cu)污染会使土壤理化性质改变,引发土壤光谱产生微弱变化,该研究目的是对Cu污染土壤光谱的特征及弱差信息进行识别、提取与分析,进而挖掘光谱中的重金属污染信息。采用包络线去除(CR)对光谱进行预处理,通过定义局部极大值均值(LMM)与半波高(HWH),结合时频分析的短时傅里叶变换(STFT)及能量谱密度(PSD),构建LH-PSD甄测模型。通过模型对极相似土壤光谱进行处理,所获PSD分布图使光谱间的微弱差异可视化显现,并显著区分了相似光谱,验证了模型对光谱特征及弱差信息的甄别能力和有效性。同时应用该模型,对不同Cu污染梯度的土壤实验光谱进行重金属污染信息的提取与分析,研究结果表明,LH-PSD甄测模型中,LMM与HWH可有效提取光谱间差异特征并以阶梯状显现。经模型处理后得到的可视化PSD分布图能直观定性判别土壤是否受重金属Cu污染,即当土壤受重金属Cu污染后,相同采样频数下,在频率为100与600Hz附近PSD分布会出现明显空缺分离,随着Cu污染浓度的增加,在100~600Hz之间PSD的分布呈逐渐稀疏态势。能量值E可定量化监测土壤Cu污染程度,即随着土壤中Cu污染浓度的增加,E值呈下降趋势,且与Cu含量的相关系数达到-0.9105,显著相关。为检验模型的可靠性,研究结合栽种玉米作物的土壤光Soil environmental safety is of great significance. When soil is contaminated by heavy metals, it will affect the safety of crops and foods and endanger human health. Therefore, it is particularly critical to look for ways to rapidly and efficiently measure heavy metal pollution in soil. Traditional chemical analysis methods have some disadvantages such as complicated process, time-consuming and labor-consuming. Hyperspectral remote sensing has obvious advantages in environmental monitoring and other applications because of its high spectral resolution, large amount of information, and rapid losslessness. Due to the complex reflection and radiation process of electromagnetic remote sensing signals, the soil hyperspectral data acquired by the instrument is difficult to directly interpret the information of heavy metal pollution. Therefore, it is very important to find out a method that can effectively excavate heavy metal pollution information in soils. The soil physicochemical properties will change because of different concentrations pollution of Cu, causing slight changes in the soil spectrum, the purpose of this study is to identify, extract and analyze the characteristics and weak difference information in the spectrum of Cu contaminated soil, and then tap the heavy metal pollution information in the spectra. In this paper, the continuum removal(CR) was used to preprocess the spectrum, the LH-PSD analysis model for analyzing soil spectra was constructed bydefining local maximum mean(LMM) and half wave height(HWH), combined with Short-time Fourier transform(STFT) of the time-frequency analysis method and power spectral density(PSD). The extremely similar soil spectrum was processed by the LH-PSD model, and the PSD distribution map visualized the faint differences between the spectra, and significantly distinguished the similar spectra, which verified the ability of the model to discriminate spectral features and weak differential information. At the same time, this model was used to extract and analyze heavy m

关 键 词：高光谱遥感 重金属污染 特征信息 甄测模型 土壤污染监测 

分 类 号：TP7[自动化与计算机技术—检测技术与自动化装置]