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平稳小波变换在冬小麦SPAD高光谱监测中的应用

姚付启1,2,蔡焕杰2**,孙金伟3,乔伟1   

  1. 1长江科学院农业水利研究所, 武汉 430010; 2西北农林科技大学旱区农业水土工程教育部重点实验室,  陕西杨凌 712100;
    3长江科学院水土保持研究所, 武汉 430010)
  • 出版日期:2015-07-18 发布日期:2015-07-18

Application of stationary wavelet transformation to winter wheat SPAD hyperspectral monitoring.

YAO Fu-qi1,2, CAI Huan-jie2, SUN Jin-wei3, QIAO Wei1   

  1. (1Institute of Agricultural Water Conservancy, Changjiang River Scientific Research Institute, Wuhan 430010, China; 2 Ministry of Education Key Laboratory of Agricultural Soil and Water Engineering in Arid Areas, Northwest A&F University, Yangling 712100, Shannxi, China; 3Institute of Soil and Water Conservation, Changjiang River Scientific Research Institute, Wuhan 430010, China)
  • Online:2015-07-18 Published:2015-07-18

摘要: 在2010与2011年度冬小麦生长季通过大田小区试验,利用ASD便携式野外光谱仪和SPAD502叶绿素计实测冬小麦冠层的高光谱反射率与SPAD值.分析不同SPAD值下的冬小麦冠层光谱特征,建立了基于归一化植被指数(NDVI)与比值植被指数(RVI)、小波能量系数的不同生育期冬小麦SPAD估算模型.结果表明: 随着SPAD值的增大,“绿峰”与“红谷”特征愈加明显.在冬小麦返青期、拔节期、抽穗期、灌浆期NDVI估算SPAD的效果较好,估算模型的R2分别为0.7957、0.8096、0.7557、0.5033.小波能量系数回归模型可以提高冬小麦SPAD的估算精度,在返青期、拔节期、抽穗期、灌浆期以高频、低频小波能量系数为自变量的冬小麦SPAD估算模型的R2分别达到0.9168、0.9154、0.8802、0.9087.

Abstract:

By field trials, the canopy hyperspectral reflectance and chlorophyll content (SPAD) for winter wheat during 2010 and 2011 growth periods were measured by the ASD portable spectrometer and portable chlorophyll meter SPAD-502, respectively. The canopy spectral characteristics of different SPAD values were analyzed in different growth periods. The winter wheat SPAD estimation models based on normalized difference vegetation index (NDVI), ratio vegetation index (RVI) and wavelet energy coefficients were established in different growth periods. The results showed that green peak and red valley characteristics became more and more obvious with the increase of the SPAD. The SPAD estimation models based on NDVI performed better at the regreening stage, elongation stage, heading stage and filling stage with determination coefficients (R2) being 0.7957, 0.8096, 0.7557 and 0.5033, respectively. The winter wheat SPAD estimation models based on wavelet energy coefficients could greatly improve the SPAD estimation accuracy, with regression determination coefficients (R2) of the PVC estimation models based on high frequency energy coefficient and low frequency energy coefficient being 0.9168, 0.9154, 0.8802 and 0.9087 at the regreening stage, elongation stage, heading stage and filling stage, respectively.