Polarized spectra-hyperspectral data fusion technique was used to estimate the soluble sugar(SS),total nitrogen(N),and their ratio(SS/N),of greenhouse tomato leaves.Fresh tomato leaves of five different growth stages(...Polarized spectra-hyperspectral data fusion technique was used to estimate the soluble sugar(SS),total nitrogen(N),and their ratio(SS/N),of greenhouse tomato leaves.Fresh tomato leaves of five different growth stages(seedling,flowering,initial fruiting,mid-fruiting and picking stage)and five different nitrogen treatments(severe stress 25%,moderate stress 50%,mild stress 75%,normal 100%,and excess 150%)at every stage were collected for spectra acquisition and SS and N determination.Polarized reflectance spectra were acquired with a polarization reflectance spectrum spectro-goniophotometer system and four polarization degree features were extracted.Hyperspectral data were collected with a hyperspectral imaging system and four reflectance spectrum features and eight image features were extracted.Initially,models were built with polarization degree features,image features,and spectral features respectively.Linear and nonlinear fusion methods were comparatively used for modeling based on normalized data of the three sources.The results suggest that the performances of SS/N models are better than those of N and SS models,and the prediction capability of the Support Vector Machine(SVM)models of N and SS/N are superior to those obtained with single kind feature.This work indicates that the polarized spectrum-hyperspectral multidimensional information detecting method can feasibly judge the tomato nutrient stress conditions.Multi-features data fusion analysis technique can enhance the prediction accuracy of spectral diagnostics technology in precision agriculture.展开更多
A sequential method for estimating the optical properties of two-layer biological tissues with spatially-resolved diffuse reflectance was proposed and validated using Monte Carlo simulations.The relationship between t...A sequential method for estimating the optical properties of two-layer biological tissues with spatially-resolved diffuse reflectance was proposed and validated using Monte Carlo simulations.The relationship between the penetration depth of detected photons and source-detector separation was first studied.Photons detected at larger source-detector separations generally penetrated deeper into the medium than those detected at small source-detector separations.The effect of each parameter involved in the two-layer diffusion model(i.e.,the absorption and reduced scattering coefficients(μa andμs′)of each layer,and the thickness of top layer)on reflectance was investigated.It was found that the relationship between the optical properties and thickness of top layer was a critical factor in determining whether photons would have sufficient interactions with the top layer and also penetrate into the bottom layer.The constraints for the proposed sequential estimation method were quantitatively determined by the curve fitting procedure coupledwith error contourmap analyses.Results showed that the optical properties of top layer could be determinedwithin 10%error using the semi-infinite diffusion model for reflectance profiles with properly selected start and end points,when the thickness of top layer was larger than two times its mean free path(mfp′).And the optical properties of the bottom layer could be estimatedwithin 10%error by the two-layer diffusion model,when the thickness of top layerwas b16 times its mfp′.The proposed sequential estimation method is promising for improving the estimation of the optical properties of two-layer tissues from the same spatially-resolved reflectance.展开更多
基金The authors are grateful to the financial support by China national key research and development plan(2017YFD0700504)China Postdoctoral Science Foundation(2016M601743)+3 种基金Senior talent research start-up fund of Jiangsu University(14JDG151)Natural Science Foundation of China Youth Fund(61901194)Natural Science Youth Foundation of Jiangsu Province(BK20180863,BK20180861)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD-2018-87).
文摘Polarized spectra-hyperspectral data fusion technique was used to estimate the soluble sugar(SS),total nitrogen(N),and their ratio(SS/N),of greenhouse tomato leaves.Fresh tomato leaves of five different growth stages(seedling,flowering,initial fruiting,mid-fruiting and picking stage)and five different nitrogen treatments(severe stress 25%,moderate stress 50%,mild stress 75%,normal 100%,and excess 150%)at every stage were collected for spectra acquisition and SS and N determination.Polarized reflectance spectra were acquired with a polarization reflectance spectrum spectro-goniophotometer system and four polarization degree features were extracted.Hyperspectral data were collected with a hyperspectral imaging system and four reflectance spectrum features and eight image features were extracted.Initially,models were built with polarization degree features,image features,and spectral features respectively.Linear and nonlinear fusion methods were comparatively used for modeling based on normalized data of the three sources.The results suggest that the performances of SS/N models are better than those of N and SS models,and the prediction capability of the Support Vector Machine(SVM)models of N and SS/N are superior to those obtained with single kind feature.This work indicates that the polarized spectrum-hyperspectral multidimensional information detecting method can feasibly judge the tomato nutrient stress conditions.Multi-features data fusion analysis technique can enhance the prediction accuracy of spectral diagnostics technology in precision agriculture.
基金The authors gratefully acknowledge the financial support provided by the Natural Science Foundation of Jiangsu Province,China(No.BK20180861)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.14KJA210001).
文摘A sequential method for estimating the optical properties of two-layer biological tissues with spatially-resolved diffuse reflectance was proposed and validated using Monte Carlo simulations.The relationship between the penetration depth of detected photons and source-detector separation was first studied.Photons detected at larger source-detector separations generally penetrated deeper into the medium than those detected at small source-detector separations.The effect of each parameter involved in the two-layer diffusion model(i.e.,the absorption and reduced scattering coefficients(μa andμs′)of each layer,and the thickness of top layer)on reflectance was investigated.It was found that the relationship between the optical properties and thickness of top layer was a critical factor in determining whether photons would have sufficient interactions with the top layer and also penetrate into the bottom layer.The constraints for the proposed sequential estimation method were quantitatively determined by the curve fitting procedure coupledwith error contourmap analyses.Results showed that the optical properties of top layer could be determinedwithin 10%error using the semi-infinite diffusion model for reflectance profiles with properly selected start and end points,when the thickness of top layer was larger than two times its mean free path(mfp′).And the optical properties of the bottom layer could be estimatedwithin 10%error by the two-layer diffusion model,when the thickness of top layerwas b16 times its mfp′.The proposed sequential estimation method is promising for improving the estimation of the optical properties of two-layer tissues from the same spatially-resolved reflectance.
