Research And Implementation Of Remote Pulse Raman Spectroscopy

In the field of substance detection,Raman scattering spectrum remote substance detection technology has been welcomed for its fast,non-destructive,high sensitivity and wide applicability.With the progress of laser technology and spectrometer technology,it has become a feasible detection means in the fields of mineral composition analysis,metal composition analysis,dangerous explosives composition analysis and so on.With the increase of detection distance,the noise interference and fluorescence interference of Raman spectrum will also increase.Excessive interference will drown the Raman scattering echo signal captured by the spectrometer,resulting in the decrease of spectral signal-to-noise ratio and the reduction of substance identification rate.How to design the algorithm of noise suppression and baseline correction,reduce the noise interference in the original Raman spectrum,eliminate the background baseline,improve the signal-to-noise ratio of the acquired spectrum,and make the processed spectral image close to the ideal spectrum,has become an important research topic in long-distance pull-down spectral matter detection.In this thesis,based on the research and analysis of the basic theory of Raman scattering spectrum,spectral technology and pretreatment technology,in order to solve the problem that the noise and background baseline interference of the original Raman spectral image are too large,this paper analyzes the composition and causes of the noise and background baseline interference factors in the original spectral image.The design of noise suppression scheme based on wavelet decomposition and correlation denoising is completed,and the design of baseline correction scheme based on punitive least squares is completed.In this thesis,through the design of simulation experiments,through the simulation of Raman spectrum and real Raman spectrum data preprocessing,verify that the design of the preprocessing scheme can effectively eliminate the noise interference in the original spectrum,reduce the background baseline,improve the spectrum signal-to-noise ratio,and verify the effectiveness of the preprocessing scheme designed in the thesis.In this thesis,we designed and carried out the remote pulse Raman spectral substance detection experiment verification work.We used the independently designed and built pulse Raman spectral detection system to carry out the 100 m distance Raman spectral substance detection experiment under the outdoor daylight condition.The pre-processing scheme designed in this paper is used to suppress the noise and eliminate the baseline of the original Raman spectrum,which verifies the de-noising and de-baseline capability of the pre-processing scheme designed in this thesis on the remote Raman spectrum,and verifies the feasibility and effectiveness of the scheme designed in this thesis.