ISREA: An Efficient Peak-Preserving Baseline Correction Algorithm for Raman Spectra
ISREA: An Efficient Peak-Preserving Baseline Correction Algorithm for Raman Spectra
复制标题
DOI：
10.1177/0003702820955245
复制
发表时间：
2020-10
影响因子：
3.5
通讯作者：
Yunnan Xu;Pang Du;R. Senger;John L. Robertson;J. Pirkle
中科院分区：
文献类型：
--
作者：
Yunnan Xu;Pang Du;R. Senger;John L. Robertson;J. Pirkle
在拉曼光谱学中的关键步骤是基线校正。该过程消除了由残余瑞利散射或荧光产生的背景信号。最近已经采用了依赖于非对称损失函数的基线校正程序。它们以减少的对正光谱偏差的惩罚来操作，正光谱偏差基本上从侵入的拉曼峰面积推低基线估计。然而，它们与多项式拟合的耦合可能不适用于整个谱域，并且可能产生不一致的基线。它们对阈值的指定和相应目标函数的非凸性的要求进一步使计算复杂化。从他们的优点和缺点，我们已经开发出一种新的基线校正程序称为迭代平滑样条根误差调整（ISREA），有三个明显的优势。首先，ISREA使用平滑样条来估计基线，这比多项式更灵活，并且能够捕获整个谱域上的复杂趋势。其次，ISREA模拟了非对称平方根损失，并消除了阈值的需要。最后，ISREA通过迭代更新预测误差和重新调整基线，避免了对非凸损失函数的直接优化。通过我们对各种光谱（包括模拟光谱、矿物光谱和透析液光谱）的广泛数值实验，我们表明ISREA简单、快速，并且可以产生一致且准确的基线，从而保留所有有意义的拉曼峰。
A critical step in Raman spectroscopy is baseline correction. This procedure eliminates the background signals generated by residual Rayleigh scattering or fluorescence. Baseline correction procedures relying on asymmetric loss functions have been employed recently. They operate with a reduced penalty on positive spectral deviations that essentially push down the baseline estimates from invading Raman peak areas. However, their coupling with polynomial fitting may not be suitable over the whole spectral domain and can yield inconsistent baselines. Their requirement of the specification of a threshold and the non-convexity of the corresponding objective function further complicates the computation. Learning from their pros and cons, we have developed a novel baseline correction procedure called the iterative smoothing-splines with root error adjustment (ISREA) that has three distinct advantages. First, ISREA uses smoothing splines to estimate the baseline that are more flexible than polynomials and capable of capturing complicated trends over the whole spectral domain. Second, ISREA mimics the asymmetric square root loss and removes the need of a threshold. Finally, ISREA avoids the direct optimization of a non-convex loss function by iteratively updating prediction errors and refitting baselines. Through our extensive numerical experiments on a wide variety of spectra including simulated spectra, mineral spectra, and dialysate spectra, we show that ISREA is simple, fast, and can yield consistent and accurate baselines that preserve all the meaningful Raman peaks.