水中矿物油三维荧光谱的特征提取与光谱重构

基于荧光激发-发射矩阵的奇异值分解方法，提取矿物油三维荧光谱的特征序列并进行光谱重构研究。对数十个水中污染油的三维荧光谱进行了奇异值分解和参数计算，表明奇异值参数具有明显的能量聚拢特性； 在适当截取奇异值特征参数后，将奇异值与相应的伴随特征向量组合构成三维荧光谱泛基因序列，实现了三维光谱反演重构。作为比较典型的示例，给出了水中柴油的原始三维荧光谱和重构三维荧光谱的对照图。重构的三维荧光谱与原始三维荧光谱基本相同。研究表明，矿物油三维荧光谱的奇异值特征谱能够代表三维荧光谱主能量的分布特征，有限的奇异值泛基因序列具有三维光谱反演重构能力。该结论对于水环境中的污染油模式识别以及矿物油荧光信息文库的建设有重要意义。

Feature Abstraction and Spectral Reconstruction of Three-Dimensional Fluorescence Spectra of Oil in Water

In the present paper,spectral reconstruction of three-dimensional fluorescence spectra of oil was studied based on singular value division(SVD)of fluorescence excitation-emission matrix(EEM).Depending on oil components,three-dimensional(3-D)fluorescence spectra of oils can be seen as their "fingerprints".Feature abstraction and selection of 3-D fluorescence spectra is important to oil identification.Statistic parameters such as the average,standard error,centroid,kurtosis,geometrical distribution as well as main-shaft slope selected,forming "apparent statistic feature" vector of 3-D fluorescence spectra of oils,are limited due to their roughness.And the apparent statistic feature vector can not support spectral reconstruction reversely.In this paper,with singular-value features abstracted from EEMs composing the feature chain,reversal spectral reconstruction can be realized,and its information loss can be estimated.In other words,a pan-gene series of 3-D fluorescence spectra consists of singular values and their corresponding accompanying vectors.By SVD operation on EEMs of dozens of oil samples in water,their singular values accompanied with corresponding vectors were calculated showing obviously gathering energy distribution.With singular values being properly cut,principal feature parameters were selected and combined with their accompanying vectors composing the pan-gene series(or singular-value pan-gene chain)and spectral reconstruction was reversely completed.A couple of spectra(original and reconstructed)of diesel as the typical oil in water were presented for comparison.It can be seen that there is no obvious difference between the reconstructed and original spectra.Certainly,information loss exists but in an scheduled extent.It is shown that the singular-value features of fluorescence excitation-emission matrix(EEM)represent spectral gathering energy,and the length-limited pan-gene chain has the ability to reconstruct three-dimensional fluorescence spectra.Practically,for common kinds of mineral oils such as crude,diesel,kerosene and lubricant,the preceding three principal parameters are enough to complete spectral reconstruction and oil identification,with every singular value being followed by its right accompanying vector respectively.This is meaningful for recognition of contaminating oil in water,and important to construct oil fluorescence database.