Abstract:
To establish a rapid and accurate classification method for Astragalus herbs. Using a differential Raman
spectrometer,88 batches of Astragalus herbs were examined under the conditions that the light source used a dualfrequency output (δλ ≤ 1 nm),a single-frequency laser with an output power of 250 mw,a linewidth of ≤ 0.06 nm,a
wavelength of 785 nm,a spectral range of 180-2800 cm-1,and a scanning time of 3 seconds. According to the difference
of Raman peaks,comparing the differential Raman spectra of the samples found that the samples could be classified
into four kinds; the raw spectra were preprocessed by standard deviation standardisation method (Z-Score); the
discriminant analysis model was used for training,and the accuracy rates under prediction set and cross-validation were
95.5% and 81.8%,respectively; the accuracy rate of the test set in the established convolutional neural network model
reached 100%; to further determine the importance of feature wavelengths for prediction,a random forest algorithm
model was built using the same training and test sets,with accuracies of 90.8% and 85.0%,respectively. Differential
Raman spectroscopy is able to detect different kinds of Astragalus herbs,and the general prediction model established is
convenient and fast,which lays a foundation for the rapid examination and analysis of Astragalus herbs.