Envelope line iteration method for trace gas Raman spectral detection baseline correction

Abstract

The invention provides an envelope line iteration method for trace gas Raman spectral detection baseline correction; a numerical differential of denoised gas Raman spectrum W is solved by using diff function, a minimum value point is solved by using find function under a condition where slope of a minimal value point left curve is less than 0and slope of a right curve is greater than 0, a primary envelope line l is obtained by using cubic spline curve interpolating function spine and the minimum value point, gas Raman spectrum non-uniform front and rear spectral peak densities is segmented, envelope lien iteration concept is introduced, an envelope line L2 (i.e., gas Raman spectral baseline) is obtained by means of a number of iterations of dense segments is greater than a number of iterations of sparse segments, and W is subtracted by the baseline L2 to finish baseline correction for W. Processing results of the invention can accurately correct trace gas Raman spectral baselines, reducing corrected spectral luminescence and improving quantitative analytical accuracy of gas Raman spectrum.

Description

technical field [0001] The invention relates to the field of gas Raman spectrum detection, in particular to the baseline correction technology of trace gas Raman spectrum. Background technique [0002] Raman spectroscopy (Raman spectroscopy) is a scattering spectrum based on the Raman scattering effect, discovered by Indian physicist Raman, and has the advantages of non-invasive, non-destructive and non-radiative. With the introduction of laser light sources, the improvement of signal detection technology and the popularization of computer technology, Raman spectroscopy is increasingly used in the fields of chemical engineering, biomedical detection and material production. [0003] However, affected by many factors such as the instrument system, detection environment, and samples, the obtained Raman spectrum detection signals always have different degrees of noise and background interference. The phenomenon that the Raman spectrum baseline is raised by factors such as fluo...

AI Technical Summary

Problems solved by technology

The cost of Raman spectroscopic analysis instrument improvement is high and the influence of fluorescent substances cannot be completely eliminated, while the data processing method is relatively low cost and effective

The existing polynomial fitting and segmented polynomial fitting algorithms are the most commonly used baseline correction methods, but they all have the problem of residual fluorescence background, which leads to poor accuracy of baseline correction, which is not conducive to improving the accuracy of gas Raman spectrum detection. Spend

The wavelet transform baseline correction method is to decompose the Raman signal into a series of superposition of sine waves, which can separate the low frequency and high frequency of the signal, and has the advantages of fast and accurate, but the decomposition scale depends on experience, which is difficult to achieve for different practical problems. The best processing effect, and the baseline correction is easy to be distorted or insufficient, and its calculation amount and computational complexity are relatively high

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