Real-time deducting background nonlinear correction method for detecting concentration of oxygen in glass bottles by means of wavelength modulation spectroscopy

Abstract

The invention discloses a real-time deducting background nonlinear correction method for detecting the concentration of oxygen in glass bottles by means of wavelength modulation spectroscopy. The real-time deducting background nonlinear correction method includes acquiring secondary harmonic data of the glass bottles with the oxygen concentration of 0% and to-be-detected glass bottles, carrying out data mean and filter processing on the secondary harmonic data, carrying out nonlinear correction and then extracting corresponding harmonic characteristic peak values P<0> and P; utilizing a half of the sum of each characteristic peak value P' of atmosphere and a characteristic peak value P'<21> of each glass bottle with the oxygen concentration of 21% when oxygen concentration inversion modelsare built as a threshold for detecting the availability of the bottles, further carrying out real-time deducting background and multiplication correction processing if the harmonic characteristic peak values P are smaller than the threshold, in other words, dividing the characteristic peak values P<0>' of the glass bottles with the oxygen concentration of 0% when the models are initially built bythe current characteristic peak values P<0> to obtain correction factors, multiplying (P-P<0>) by the correction factors to obtain actual characteristic peak values of corresponding to-be-detected samples and feeding the characteristic peak values of the to-be-detected samples into the concentration inversion models to predict the concentration of the oxygen in the glass bottles. The real-time deducting background nonlinear correction method has the technical advantages that background fluctuation can be suppressed, and the precision and the stability of prediction for the concentration of the oxygen in the glass bottles can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of gas detection, in particular to a real-time background-subtraction nonlinear correction method mainly used for detecting oxygen concentration in a glass bottle based on wavelength modulation spectrum. Background technique [0002] In the pharmaceutical industry, international companies have applied wavelength modulation spectroscopy (WMS) technology to the detection of oxygen concentration in sealed glass vials, such as LIGHTHOUSE in the United States and Bevitti in Italy. However, the second harmonic signal extracted by WMS technology has background fluctuations. Due to the influence of optical noise caused by the glass bottle wall, system instrument noise, nonlinear intensity modulation, and random free space temperature and humidity, the background fluctuations are irregular. , so that the concentration-peak inversion model has different degrees of nonlinearity, which affects the accuracy and stability...

AI Technical Summary

Problems solved by technology

However, the second harmonic signal extracted by WMS technology has background fluctuations. Due to the influence of optical noise caused by the glass bottle wall, system instrument noise, nonlinear intensity modulation, and random free space temperature and humidity, the background fluctuations are irregular. , so that the concentration-peak inversion model has different degrees of nonlinearity, which affects the accuracy and stability of concentration measurement

[0003] At present, in the real-time subtraction background nonlinear correction research of spectral technology, Werle et al. proposed to collect the spectral line signal of the background gas first, and then collect the spectral line absorption signal of the target gas for subtraction. Persson et al. improved the optical path or gas chamber structure. Non-linear processing is used to reduce the influence of the baseline, but all of them are only suitable for systems with gas absorption cells; there are many methods for data preprocessing to perform baseline correction. Sex is not strong

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