Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
Analyst. 2010 Jun;135(6):1382-8. doi: 10.1039/b927501k. Epub 2010 Apr 19.
A standardization algorithm based on the application of Tucker3 models on the tensorized measurement signals is proposed to transfer calibration information between two Raman spectrometers. The secondary instrument in this study is a low cost and portable CCD based unit employing an efficient 532 nm green laser. The primary instrument is a high performance Fourier-transform based laboratory instrument using a low efficiency NIR laser at 1064 nm, albeit with very limited sample fluorescence interference. This work is a first investigation of calibration transfer on Raman spectral data which include different values of fluorescent background from one instrument to the other. The spectra of a small set of calibration samples are measured on both spectrometers. Using the ability of Tucker3 to estimate missing values in tensorized data, we reconstruct the spectrum of a new sample on the primary instrument based on its measured response of the secondary instrument without the need for constructing an explicit transfer model. This way spectra of a prediction sample measured on one spectrometer can be successfully transferred to another spectrometer as if it has been measured directly on the latter. Hence, the task of calibration transfer among instruments is posed as a missing data problem. A discrete wavelet transform is performed to improve the predictive ability. Performance criteria for judging the success of the calibration transfer are reported as the standard error of prediction for estimation of samples in a prediction set. By comparison, the proposed Tucker3 based standardization method shows a better performance as compared to piecewise direct standardization. The method is expected to be applicable for performing calibration transfer using data from instruments other than Raman spectrometers.
提出了一种基于 Tucker3 模型在张量化测量信号上的应用的标准化算法，用于在两台拉曼光谱仪之间传递校准信息。本研究中的辅助仪器是一种低成本、便携式的基于 CCD 的单元，采用高效的 532nm 绿光激光器。主要仪器是一种高性能的基于傅里叶变换的实验室仪器，使用效率较低的 1064nm 近红外激光，尽管样品荧光干扰非常有限。这项工作是首次对拉曼光谱数据进行校准转移的研究，其中包括一台仪器到另一台仪器的荧光背景值不同。在两台光谱仪上测量了一组校准样品的光谱。利用 Tucker3 估计张量化数据中缺失值的能力，我们可以根据辅助仪器测量的主要仪器的响应，在主要仪器上重建新样品的光谱，而无需构建显式转移模型。这样，一台光谱仪上测量的预测样品的光谱就可以成功地转移到另一台光谱仪上，就好像它是直接在后者上测量的一样。因此，仪器之间的校准转移任务被表述为一个缺失数据问题。执行离散小波变换以提高预测能力。报告了用于判断预测集中样本估计的校准转移成功的性能标准，即预测误差的标准误差。相比之下，与分段直接标准化相比，所提出的基于 Tucker3 的标准化方法表现出更好的性能。预计该方法适用于使用除拉曼光谱仪之外的仪器的数据进行校准转移。
