Research on the measurement of CO₂ concentration based on multi-band fusion model

Abstract

In this paper, a multi-band fusion model to improve the performances of the super-continuum laser absorption spectrometer (SCLAS) of CO₂ was proposed and demonstrated. Various concentrations of CO₂ were measured by the super-continuum laser in the wavelength of 1425–1445 nm, 1565–1585 nm, and 1595–1615 nm, respectively, at 295 K and 1 atm. The method for derivation of CO₂ concentration using the integrated area of spectrum peaks is proposed. Linear models of the CO₂ concentration and the integrated area of the absorption peaks in different bands were established, which achieves R² of 0.9947, 0.9937, and 0.9824, respectively. The measurement accuracy with the models is evaluated with the parameter of relative analysis error (RPD), which results in a of more than 2, indicating reasonable prediction ability of the models. In order to improve the accuracy of the single model, the models of the three bands are weighted and fused based on R² and RMSE, respectively. One of the fusion models reduces the prediction error and improves the accuracy of the single model effectively by decreasing the maximum relative error from 3.4 to 1.2% for a single model. The experimental results show that SCLAS can measure the CO₂ concentration under different environments. The multi-band fusion model proposed here is feasible for CO₂ measurement, which provides a new idea and new method for the detection of gases.