一种基于中值滤波和统计学的拉曼光谱spike剔除算法  

A Spike Removal Algorithm Based on Median Filter and Statistic for Raman Spectra

作　　者：叶瑞乾 何浩 郑鹏 徐梦溪[2] 王磊 YE Rui-qian;HE Hao;ZHENG Peng;XU Meng-xi;WANG Lei(School of Aerospace Engineering,Xiamen University,Xiamen 361101,China;State Key Laboratory of Physical Chemistry of Solid Surfaces,Collaborative Innovation Center of Chemistry for Energy Materials(iChEM),College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361101,China)

机构地区：[1]厦门大学航空航天学院,福建厦门361101 [2]厦门大学化学化工学院,固体表面物理化学国家重点实验室,能源材料化学协同创新中心(iChEM),福建厦门361101

出　　处：《光谱学与光谱分析》2022年第10期3174-3179,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21373173)资助。

摘　　要：拉曼光谱是一种已广泛应用于化学、生物学和物理学的技术。然而拉曼光谱仪的电荷耦合器件很容易受到宇宙射线的影响,从而产生随机的窄带宽、高强度的spike。在真实样品中出现概率较低,约为千分之一,但一旦出现将严重降低信号对比度。该研究提出一种实用的spike剔除算法。该算法对中值滤波后的数据与原始数据作差,得到偏差数据。用分位数的方法将偏差数据从小到大排序,取中间99%数据作为真实数据作高斯分布拟合。根据spike强度高,稀疏的特性,以光谱中高强度数据的出现概率作为阈值标准剔除spike。最后以中值滤波结果带入原始数据代替spike,从而最大程度还原样本原始信息且不需任何调试参数。以加入不同强度spike的拉曼光谱作为验证对象,实验结果表明本算法对spike检测与去除的灵敏度可以高达99.5%。本算法同时适用于一维拉曼光谱、二维拉曼图像和三维拉曼数据立方体,且算法表现随着维度的增加而提高,一维spike剔除算法能检测超过最大峰强度40%的spike,而在三维拉曼数据立方体中,超过峰值20%的spike即能被检测出。用该算法对40000条真实拉曼光谱进行处理,可以在不扭曲真实信号的情况下有效地剔除spike,进一步证明了算法的实用性。Raman spectroscopy is a promising technique widely used in chemistry,biology,and physics.However,as the key part of the Raman spectrometer,the charge-coupled device is vulnerable to cosmic rays,resulting in a random narrow bandwidth and a high-intensity spikes.It will cause a significant reduction in signal contrast.In this paper,we propose a practical spike removal algorithm.Firstly,the algorithm obtains deviation data by separating the median filtered data from the original data.Then,deviation data is sorted from small to large by quantile method,and the intermediate 99%data are selected for Gaussian distribution fitting.Considering the characteristics of high-intensity and sparsity of the spike,the occurrence probability of high intensity data in the spectra is used as the threshold standard to remove spike.Finally,the spikes are replaced by new data using median filtered at corresponding positions.This algorithm restores the original sample information without any debugging parameters.Different intensities of spikes are added in Raman spectra to verify the algorithm,and the experimental results show that this algorithm’s sensitivity can reach 99.5%.Besides,this algorithm is applicable for one-dimensional Raman spectra,two-dimensional Raman images and three-dimensional Raman data cubes,and the performance improves with the increase of dimensionality.Specifically,the one-dimensional spike removal algorithm can detect spikes exceeding 40%of the maximum peak intensity.The Raman data cubes can be detected exceeding 20%of the peak value.The algorithm is used to process 40000 real Raman spectra and can effectively remove spikes without distorting the real signal,proving the algorithm’s practicability.

关 键 词：拉曼光谱 宇宙射线 中值滤波 spike剔除 

分 类 号：O657.37[理学—分析化学]