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    基于聚类分析的局部建模方法在茶叶近红外光谱分析中的应用

    Application of Local Modelling Based on Cluster Analysis to NIRS Analysis of Tea

    • 摘要: 为提高茶叶中咖啡碱、氨基酸近红外光谱分析模型的预测精度,采用基于聚类分析的局部建模方法.先提取茶叶样品光谱数据的特征因子,使用聚类分析对样品进行硬划分,经样品间距离和类间距离判别,确定单个模型定标样品个数.完成特征谱带的分析并进行波段选择后,随机抽取15个样品,偏最小二乘法局部建模结果显示:咖啡碱、氨基酸的预测平均相对偏差分别由聚类前的5.80%和6.14%下降为聚类后的2.75%和2.44%,模型预测精度显著提高.

       

      Abstract: The local modelling based on cluster analysis was applied to NIRS analysis of tea to promote the predictive testing precision in determination of its caffeine and amino acid contents.The characteristic factors of spectral data of tea sample were collected,and crisp partition of the samples was done by cluster analysis.Through differentiation of the sample distances and inter-class distances,number of target sample with single model was determined.After completion of analyzing the characteristic spectral bands and of selection of wave sections,15 samples were taken at random for cluster analysis.Results of local modelling by PLS were obtained as follows: the values of average relative deviation of predictive testing of caffeine and amino acids were decreased from 5.80% and 6.14% (before cluster analysis) to 2.75% and 2.44% (after cluster analysis) respectively,showing a remarkable improving of the precision of modelling predictive testing.

       

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