基于高光谱成像技术的中药栀子产地识别

Origin identification of Gardeniae Fructus based on hyperspectral imaging technology

为实现快速无损识别中药栀子的产地,建立一种基于高光谱成像技术的方法。利用高光谱成像系统分别从可见-近红外波段(410~990 nm, VNIR)和短波红外波段(950~2 500 nm, SWIR)获取8个产地栀子样品的高光谱图像,使用ENVI 5.3软件提取并计算感兴趣区域内的平均光谱反射率,最终获得1 600个样品的光谱数据。将VNIR和SWIR的光谱数据结合即得覆盖410~2 500 nm的可见-短波红外波段(即融合波段)光谱数据。从VNIR、SWIR和融合波段这3个维度,使用多元散射校正、Savitzky-Golay平滑、标准正态变换、一阶导数(FD)和二阶导数等5种常用的预处理方法,对3组光谱数据进行降噪处理。使用偏最小二乘判别分析、线性支持向量机分类器(LinearSVC)和随机森林这3种分类算法分别建立栀子产地识别模型。结果表明,融合波段光谱数据经FD预处理后建立的栀子产地识别模型结果较好。根据混淆矩阵评估结果,使用LinearSVC构建的模型预测集识别准确率达到100%,确定栀子产地最佳识别模型为融合波段-FD-LinearSVC。因此,高光谱技术能够实现快速、无损、准确地识别不同产地栀子样品,可为栀子及其他中药材鉴别检测提供技术参考。

In order to realize rapid and non-destructive identification of the origin of Gardeniae Fructus, a technical method based on hyperspectral imaging technology was established in this study. Spectral information of Gardeniae Fructus samples from eight production origins was acquired from visible NIR(410-990 nm, VNIR) and short wavelength NIR(950-2 500 nm, SWIR) bands based on hyperspectral imaging techniques. The average spectral reflectance within the region of interest was extracted and calculated using the ENVI 5.3 software, resulting in 1 600 sample data. The visible short wavelength infrared band(fused bands) spectral data covering the range 410-2 500 nm were obtained after combining the spectral data of VNIR and SWIR. Data were de-noised by five common preprocessing methods, including multivariate scatter correction, Savitzky-Golay smoothing, standard normal variate, first derivative(FD), and second derivative from VNIR, SWIR, and fused bands(VNIR+SWIR). Partial least squares discriminant analysis, linear support vector classification(LinearSVC), and random forest were used to establish the model for origin identification of Gardeniae Fructus. The results indicated that the identification model of Gardeniae Fructus origin established after FD pretreatment of the spectral data in the fused bands could yield good results. According to the confusion matrix evaluation results, the model prediction set using LinearSVC reached 100% accuracy, so the optimum identification model of Gardeniae Fructus origin was determined as fusion bands-FD-LinearSVC. Therefore, the hyperspectral imaging technology can achieve rapid, nondestructive, and accurate identification of Gardeniae Fructus samples of different origins, which provides a technical reference for the differential detection of Gardeniae Fructus and other Chinese medicines.