Wavelet-based detection of crop zinc stress assessment using hyperspectral reflectance
Wavelet-based detection of crop zinc stress assessment using hyperspectral reflectance
复制标题
使用高光谱反射率进行基于小波检测的作物锌胁迫评估
DOI：
10.1016/j.cageo.2010.11.019
复制
发表时间：
2011-09-01
影响因子：
4.4
通讯作者：
Zhong, Binqing
中科院分区：
文献类型：
--
作者：
Liu, Meiling;Liu, Xiangnan;Zhong, Binqing
准确检测重金属胁迫对作物生长的影响对农业生态环境和粮食安全至关重要。利用小波分析方法对作物的高光谱反射率进行分析，探索奇异参数作为作物锌胁迫水平评价的指标。实验场地位于中国吉林省长春市。收集了水稻、玉米、大豆和白菜4种锌污染土壤作物的高光谱和生物化学数据。对作物的高光谱反射率（350 ~ 1300 nm）进行小波变换，并探索了奇点范围（S(R)）、奇点幅度（S(a)）和Lipschitz指数（alpha）这三类奇点参数作为作物Zn胁迫的指标。结果表明：(1)利用Daubechies 5 （db5）母小波的第5分解层次小波系数可以较好地识别作物锌胁迫；Zn胁迫下，作物集中在该区域的S(R)光谱信号在550 ~ 850 nm左右；（ii） S(R)趋于稳定，但S(A)和α在作物生长阶段发生了一些变化；(3) 4种作物的S(R)、S(A)和α存在差异；S(A)随作物种类S(R)的增加而增加；（iv） α与Zn浓度呈较强的非线性关系（R(2):0.7601 ~ 0.9451）；S(A)与Zn浓度呈较强的线性关系（R(2):0.5141 ~ 0.8281）。奇异参数可以作为作物锌胁迫水平的指标，也可以定量分析谱信号的奇异性。小波变换技术在作物重金属胁迫检测中具有广阔的应用前景。(C) 2011 Elsevier Ltd.版权所有。
Accurate detection of heavy metal-induced stress on the growth of crops is essential for agricultural ecological environment and food security. This study focuses on exploring singularity parameters as indicators for a crop's Zn stress level assessment by applying wavelet analysis to the hyperspectral reflectance. The field in which the experiment was conducted is located in the Changchun City, Jilin Province, China. The hyperspectral and biochemistry data from four crops growing in Zn contaminated soils: rice, maize, soybean and cabbage were collected. We performed a wavelet transform to the hyperspectral reflectance (350-1300 nm), and explored three categories of singularity parameters as indicators of crop Zn stress, including singularity range (S(R)), singularity amplitude (S(A)) and a Lipschitz exponent (alpha). The results indicated that (i) the wavelet coefficient of the fifth decomposition level by applying Daubechies 5 (db5) mother wavelets proved successful for identifying crop Zn stress; the S(R) of crop concentrated on the region was around 550-850 nm of the spectral signal under Zn stress; (ii) the S(R) stabilized, but S(A) and alpha had developed some variations at the growth stages of the crop; (iii) the S(R), S(A) and alpha were found among four crop species differentially; and moreover the S(A) increased in relation to an increase in the S(R) of crop species; (iv) the alpha had a strong non-linear relationship with the Zn concentration (R(2):0.7601-0.9451); the S(A) had a strong linear relationship with Zn concentration (R(2):0.5141-0.8281). Singularity parameters can be used as indicators for a crop's Zn stress level as well as offer a quantitative analysis of the singularity of spectrum signal. The wavelet transform technique has been shown to be very promising in detecting crops with heavy metal stress. (C) 2011 Elsevier Ltd. All rights reserved.