Baseline Correction And Noise Suppression Of Raman Spectroscopy

Raman spectroscopy is a scattering spectrum,which can provide fast,simple,repeatable detection as a new development of the analytical means.However,in application,when the laser stimulates the measured material,the environment and equipment noise as well as the fluorescence interference are brought into the receiving.The interference may cause baseline drift,which reduces the quality of Raman spectrum and affect the accuracy of material testing.Therefore,it is important to carry out the research of Raman spectrum baseline correction and noise suppression technology.In this thesis,the theoretical analysis,simulation analysis and experimental verification are carried out,and the noise suppression and baseline correction techniques are studied for the noise and baseline drift in Raman spectrum.This thesis describes the basic theory of Raman spectroscopy,analyzes the source and classification of noise in Raman spectroscopy,and studies the causes of baseline drift in Raman spectroscopy.The noise suppression technique is studied.On the basis of the respective limitations of moving window averaging method,moving window mean method and Savitzky-Golay least squares method,the design of noise suppression scheme based on multi-scale adaptive dynamic window averaging method is completed and the scheme is verified.Noise effect.The scheme solves the problem that the degree of noise suppression and the degree of spectral distortion can not be taken into account in the Raman spectrum noise suppression technology,and the noise suppression is realized.Then,aiming at the phenomenon of baseline drift in Raman spectroscopy,this paper discusses the limitations of minimized piecewise linear fitting method and moving window local extremum median method,and completes the baseline correction scheme based on local dynamic moving average adaptive method.And the baseline correction effect of the scheme is verified by simulation.The scheme calculates the residuals of the baseline by calculating the residuals of the baselines in each iteration and compares them with the standard deviations to automatically determine the fitting interval width,solves the problem of inaccurate baseline estimation in the baseline correction technique,and achieves the baseline correction adaptive.Finally,a Raman spectroscopic material detection system was constructed and the Raman spectroscopy test was carried out,it verified the feasibility and effectiveness of the baseline correction scheme and the noise suppression scheme in practical use.