基于平稳小波变换的冬小麦覆盖度高光谱监测"  

Monitoring Winter Wheat Percentage Vegetation Cover Based on Stationary Wavelet Transformation Derived from Hyperspectral Reflectance

作　　者：姚付启[1] 蔡焕杰[1] 王海江[2] 张倩[1] 王健[1] 

机构地区：[1]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 [2]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《农业机械学报》2012年第3期173-180,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金资助项目(51179162);国家科技支撑计划资助项目(2011BAD29B01)

摘　　要：在2010与2011年度冬小麦生长季,通过大田小区试验,实测了冬小麦冠层的高光谱反射率与覆盖度。分析了不同覆盖度下的冬小麦冠层光谱特征以及不同生育期冬小麦冠层光谱反射率与覆盖度的相关性,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覆盖度估算模型。结果表明:覆盖度越大,冬小麦光谱反射率在可见光波段越小,在近红外波段越大。在可见光波段,光谱反射率与覆盖度负相关,在"红边"处,由负相关变成正相关。在返青期、拔节期,NDVI估算效果好(R2为0.835 9、0.805 7);在抽穗期、灌浆期,RVI估算效果好(R2为0.803 1、0.829 4)。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覆盖度估算模型的R2分别达到0.911 2、0.895 4、0.880 2、0.927 5。By field trials, the canopy hyperspectral reflectance and percentage vegetation cover （PVC） for winter wheat during 2010 and 2011 growth periods were measured. The canopy spectral characteristic of different PVC and the relationship between canopy reflectance and PVC were analyzed in different growth periods. The winter wheat PVC estimation models based on normalized difference vegetation index （NDVI） , ratio vegetation index （RVI） , wavelet energy coefficients were established in different growth periods. The results showed that the spectral reflectance of winter wheat decreased in visible bands, however, increased in near infrared bands following the PVC increased. The spectral reflectance was negatively correlated with the PVC in visible bands, but the correlation coefficient turned to positive correlation near the red edge. The PVC estimation models based on NDVI was performed better at the regreening stage and elongation stage with determination of coefficient （RE） 0. 835 9 and 0. 805 7, respectively. However, the PVC estimation models based on RVI was better at the heading stage, filling stage with Rz 0. 803 1 and 0. 829 4, respectively. R2 of the PVC estimation models based on high frequency energy coefficient and low frequency energy coefficient were 0. 911 2, 0. 895 4, 0. 880 2, and 0. 927 5 at the regreening stage, elongation stage, heading stage and filling stage, respectively.

关 键 词：冬小麦 覆盖度 高光谱遥感 平稳小波变换 估算模型 

分 类 号：S127[农业科学—农业基础科学]