Study on the Polarized Reflectance-Hyperspectral Information Fusion Technology of Tomato Leaves Nutrient Diagnoses
ZHU Wen-jing1, MAO Han-ping1*, LI Qing-lin1, LIU Hong-yu1, SUN Jun2, ZUO Zhi-yu1, CHEN Yong2
1. Key Laboratory of Modern Agricultural Equipment and Technology，Ministry of Education & Jiangsu Province，Institute of Agricultural Engineering，Jiangsu University，Zhenjiang 212013，China 2. Institute of Electrical and Information Engineering，Jiangsu University，Zhenjiang 212013，China
Abstract：With 25%, 50%, 75%, 100% and 150%, five levels of, nitrogen(N), phosphorus(P) and potassium(K) nutrition stress samples cultivated in Venlo type greenhouse soilless cultivation mode as the research object, polarized reflectance spectra and hyperspectral images of different nutrient deficiency greenhouse tomato leaves were acquired by using polarized reflectance spectroscopy system developed by our own research group and hyperspectral imaging system respectively. The relationship between a certain number of changes in the bump and texture of non-smooth surface of the nutrient stress leaf and the level of polarization reflected radiation was clarified by scanning electron microscopy (SEM). On the one hand, the polarization spectrum was converted into the degree of polarization through Stokes equation, and the four polarization characteristics between the polarization spectroscopy and reference measurement values of N, P and K respectively were extracted. On the other hand, the four characteristic wavelengths of N, P, K hyperspectral image data were determined respectively through the principal component analysis, followed by eight hyperspectral texture features extracted corresponding to the four characteristic wavelengths through correlation analysis. Polarization characteristics and hyperspectral texture features combined with each characteristics of N, P, K were extracted. These 12 characteristic variables were normalized by maximum-minimum value method. N, P, K nutrient levels quantitative diagnostic models were established by SVR. Results of models are as follows: the correlation coefficient of nitrogen r=0.961 8, root mean square error RMSE=0.451; correlation coefficient of phosphorus ｒ=0.916 3, root mean square error RMSE=0.620; correlation coefficient of potassium ｒ=0.940 6, root mean square error RMSE=0.494. The results show that high precision tomato leaves nutrition prediction model could be built by using polarized reflectance spectroscopy combined with high spectral information fusion technology and achieve good diagnoses effect. It has a great significance for the improvement of model accuracy and the development of special instruments. The research provides a new idea for the rapid detection of tomato nutrient content.
Key words：Tomato leaf;Nitrogen;phosphorus and potassium;Polarization characteristics;Hyperspectral texture feature;Support vector regression
朱文静1，毛罕平1*，李青林1，刘红玉1，孙 俊2，左志宇1，陈 勇2 . 偏振-高光谱多维光信息的番茄叶片营养诊断 [J]. 光谱学与光谱分析, 2014, 34(09): 2500-2505.
ZHU Wen-jing1, MAO Han-ping1*, LI Qing-lin1, LIU Hong-yu1, SUN Jun2, ZUO Zhi-yu1, CHEN Yong2 . Study on the Polarized Reflectance-Hyperspectral Information Fusion Technology of Tomato Leaves Nutrient Diagnoses . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2014, 34(09): 2500-2505.
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