Fig. 1. Principle diagram of inversion algorithm for oil film

Fig. 2. The relationship between E' and R_t/R

Fig. 3. Experimental equipment structure

Fig. 4. Spectral signals collected in the experiment
(a): Background fluorescence and Raman scattering light spectra of sea water; (b): Fluorescence spectra of 10 μm oil film;(c): Fluorescence spectra of crude oil films with different thickness; (d): Fluorescence spectra of diesel oil films with different thickness

Fig. 5. Feature fluorescence spectrum with different iterations

Fig. 6. Error of K_o with different iterations

Fig. 7. Error introduced by K_o

Fig. 8. Errors of oil films with different thickness
(a): Crude oil; (b): Diesel oil