Fig. 1. Schematic diagrams of experimental setup and sample preparation process. (a) Schematic diagram of LIBS-LIF system setup;

Fig. 2. Spectra of kelp samples. (a) LIBS spectra; (b) LIBS-LIF spectra

Fig. 3. Prediction results based on LIBS-LIF univariate quantitative analysis and bispectral fusion multivariate quantitative analysis.

Fig. 4. Feature importance analysis and spectra of LIBS-LIF and LIBS after fusion. (a) Schematic diagram of feature importance; (b) schematic diagram of fusion spectra

Fig. 5. Schematic diagram of feature equilibrium processing process. (a) Schematic diagram of the original spectral fusion; (b) schematic diagram of the spectra before and after the interpolation of the LIBS-LIF spectrum and the selection of the peak fragment for LIBS spectrum; (c) SVR multiple regression importance analysis result of characteristic equilibrium spectra

Fig. 6. Performance analysis of feature equilibrium method in SVR regression

Fig. 7. Comparison of prediction performances for different regression models. (a) RMSE; (b) R²