Chlorophyll Content Inversion with Hyperspectral Technology for Apple Leaves Based on Support Vector Regression Algorithm
To realize the chlorophyll content inversion with hyperspectral technology for apple leaves,the spectral data and SPAD values were obtained by SVC HR-1024i full band spectrometer and SPAD-502 portable chlorophyll analyzer,respectively.The correlation of original spectral data,the first derivative spectral data and measured SPAD values were analyzed,various spectral parameters were selected based on the sensitive wave bands and models between spectral parameters and measured SPAD values were established.The original spectra and the SPAD value were significantly negatively correlated in visible bands,and significantly positively correlated in NIR bands.The first order derivations of spectra and the SPAD value were negatively correlated in blue and green light bands,and positively correlated in yellow and red light bands.The SPAD inversion model based on NDVI and R565 fitted well.The first derivative spectral data and measured SPAD values had improved correlation coefficient compared with the original spectral data,and the determination coefficient R2 in the inspection process of models establishment based on normalized difference vegetation index (NDVI) and R565 were 0.889 6 and 0.852 4,which showed better prediction ability than other models.To avoid the difference of order of magnitude,the spectral parameters and measured SPAD values were normalized,and polynomial regression and support vector regression (SVR) were carried out by using the normalized spectral parameters and SPAD values.The R2 in the modeling process and inspection process of SVR inversion model were 0.741 0 and 0.891 4 with root mean square error of 0.133 2 and 0.125 6,respectively,which indicated that the SVR inversion had high precision and good prediction ability.Compared with polynomial regression,the SVR algorithm had better inversion effect,thus it can be used as an optimization algorithm for chlorophyll content inversion.
apple leaveschlorophyllspectral parametersSPAD valuesupport vector regressioninversion
国家科技期刊平台
NSTL
万方数据
维普
