Corn Chlorophyll- a Concentration and LAI Estimation Models Based on Wavelet Transformed Canopy Hyperspectral Reflectance
In order to evaluate the precision of hyperspeetral reflectance model for monitoring eom Chlorophyll a eoncentration and leaf area index (IAI), eom canopy reflectance data were collected with ASD spectroradiometer (350 - 1050nm) in 2003 and 2004 at two sampling sites, one was at Changchun suburban area, and the other was in Hailun Black Soil Ecology Station, Chinese Academy of Sciences. First, four vegetation indices(NDVI,SAVI,MTVI2,SUM_FDR) were applied to regress against eom chlorophyll a concentration and LAI; Secondly, eom canopy reflectances were transformed with wavelet analysis, and extracted wavelet energy coefficient were applied in regression model for chlorophyll a concentration and IAI estimation. It were found that these four vegetation indices have intimate correlation with corn chlorophyll a concentration and/.Al, with regression determination eoefficient R2 greater than 0. 70. Single variable regression model based upon wavelet extracted reflectance energy coefficient can accurately estimate eom chlorophyll a eoncentrafion and IAI,ia for chlorophyll a concentration and IAI were O. 79, 0. 82 respectively, while with multivariate regression model, R2 were O. 87, 0. 90 for chlorophyll a concentration and LAI respectively. By above analysis, it indicated that wavelet analysis can be applied to in-situ collected hyperspectral data for com chlorophyll a concentration and IAI estimation with better performance. And in the future, wavelet analysis methods should be applied to hyperspectral data for other vegetation biophysical and biochemical parameters esfimation.
hyperspectralehlorophyll-a concentrationvegetation indexwavelet energy coefficient
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