近红外光谱分析中的变量选择算法研究进展

随着人们对近红外光谱分析技术了解的深入,人们发现通过剔除近红外光谱中的冗余变量不仅可以简化近红外光谱分析模型,提高模型的可解读性,通常还可以提高模型的预测效果及稳健性。变量选择的有效性已经在各种近红外光谱应用体系中得到了广泛的验证,发展成为了近红外光谱分析建模过程中一个越来越重要的步骤。为此,化学计量学家们近些年来开发了大量原理不同的新型变量选择算法,基于各种原理的衍生算法也层出不穷。为了让近红外光谱分析研究人员能够较为迅速地对这些算法的特点有所认识,对目前常见的各种变量选择算法的算法原理和优缺点进行了梳理。根据各种算法依据的原理不同,将目前近红外光谱领域常见的变量选择算法大致分为基于偏最小二乘模型参数,基于智能优化算法,基于连续投影策略,基于模型集群分析策略和基于变量区间等五类。在梳理的过程中,我们发现变量选择算法的发展趋势目前主要集中在以下两点:第一,算法的复杂程度不断提高;第二,不同变量选择算法之间的联用开始逐渐增多。此外,作者结合自身在应用变量选择算法时的体会和思考,还总结了变量选择算法在应用层面上存在的一些问题。例如光谱预处理方法对变量选择算法使用效果的影响,以及部分算法存在的稳定性较差,选择变量的可靠性存疑等。

Research Advance of Variable Selection Algorithms in Near Infrared Spectroscopy Analysis

Researchers begin to realize that near infrared spectroscopy analysis mod el can be simplified by removing some redundant variabl es from the full-spectrum with the growing understanding of near infrared spect roscopy.It is obvious that the simplified model constructed with retained infor mative variables can be interpreted more easily.Moreover,both prediction perfo rmance and robustness of calibration model can be improved wi hvariable selectio n,which has been proved in numerous applied examples.Therefore,variable selec tion has become a critical step in the process of constructing near infrared spe ctroscopy analysis models,and various kinds of variable selection algorithms an d their derivative algorithms have been developed by chemometrics scientists.In order to help the researchers in near infrared spectroscopy analysis field to h ave a fast overview on variable selection algorithms,we try to review some vari able selection algorithms commonly used in near infrared spectroscopy area in th is article,including their main rationales and characteristics.These variable selection algorithms are divided into five categories according to their differe nt features.These algorithms are based on parameters of partial least squares (PLS) model,intelligent optimization algorithms,successive projections strategy,model population analysis strategy,and spectral intervals respectively.Durin g the process of carding literatures,we find that the development trends of var iable selection algorithms mainly focus on two points:firstly,complexity of ne w proposed algorithms increaces continually;secondly,the combination of differ ent algorithms becomes more and more popular.Furthermore,we also summarized se veral specific applied problems that may be occurred when variable selection alg orithms are applied in near infrared spectroscopy analysis area.For example,ho w do different spectral pretreatment methods affect the performance of variable selection algorithm? How to address the poor stability and reliability of some variable selection algorithms?