一种新的多元校正模型分子光谱传递方法

无论是近红外还是红外光谱，多元校正模型的传递问题都尚未解决。为了实现模型和光谱的传递，提出了一种改进的PDS算法——SA-PDS算法，论方法通过PDS算法进行模型传递，使用光谱间的夹角大小作为判定准则来选择传递参数，使得模型传递过程不受到样品性质参考值的影响，也不再依赖于模型，并且可以双向传递。该方法分别通过在近红外数据和中红外数据中应用来证明模型传递的可行性，实验收集烟叶样本测得其近红外光谱，沥青样本测得其中红外光谱，将烟叶总糖会计师和沥青蜡含量作为模型预测对象。使用光谱夹角作为PDS参数选择标准与使用预测标准偏差作为判定准则相比，实验表明：对于近红外光谱的从机向主机的传递，其验证集预测精密度RMSEP从5.257 4降低至1.337 1，优于RMSEP(1.350 3)方法，预测偏差也同样被改善。对于中红外光谱从机向主机的传递，新方法验证集预测精密度RMSEP从0.525 1降低至0.186 9，优于RMSEP(0.219)方法。主机向从机的传递也取得了满意的传递结果。

A New Spectra Transfer Method for Multivariate Calibration Model of Molecular Spectroscopy Analysis

Whether it is for near-infrared (NIR) spectra or mid-infrared (MIR) spectra, the issue of multivariate calibration model transfer between spectrometers has not been satisfactorily solved yet. To realize the sharing of model or spectra between the spectrometers, an improvedpiecewise direct standardization (PDS) method, Spectra-Angle-PDS (SA-PDS), is proposed in this work. Spectral angle (SA) measurement which can evaluate the similarity between spectra or the difference between the spectral vector and the shape of the spectral curve is used as a criterion for optimization of parameters of PDS. The model transfer no longer needs reference data so that the model transfer is not affected by the error of properties of validation samples and the model. The model transfer from master spectrometer to slave one or opposite on the contrary can be more easily realized with SA-PDS. The proposed spectra transfer method (SA-PDS) has been applied to predict the content of glycosides in tobacco and thecontent of wax in asphalt using NIR and MIR spectra respectively. The PDS method using RMSEP to select parameters has also been performed for comparative study of the proposed model transfer technique. For the spectra transfer from salve to master spectrometers of NIR, comparative experiment results have shown thatthe root-mean-square error of prediction (RMSEP)with the proposed SA-PDS method is reduced from 5.257 4 (before transfer) to 1.337 1 (after transfer), and much smaller than that with PDS method (1.350 3). For the spectra transfer from salve to master spectrometers of MIR, the precision of model transfer also improved significantly, accompanied by the reduction in RMSEP from 0.525 1 to 0.186 9, is proven to be better than that with PDS method (0.219 4). The satisfactory spectra transfer results with the proposed SA-PDS method from the master spectrometer to the slave spectrometer has also been verified.