Fig. 1. Schematic diagram of the surface reflection properties of the different media

Fig. 2. Schematic diagram of the BRDF calculations

Fig. 3. Schematic diagram of the radiance measurement system

Fig. 4. Reflection brightness and BRDF measurements in 3~5 μm bands

Fig. 5. Reflection brightness and BRDF measurements in 8~14 μm bands

Fig. 6. Schematic diagram of the humpback whale's ascending spiral predation method

Fig. 7. IWOA algorithm flow chart

Fig. 8. Improved effect of the IWOA model in the 3~5 μm band

Fig. 9. Comparison of the inversion results of the IWOA model in the 3~5 μm band

Fig. 10. Comparison of the inversion results of the IWOA model in the 8~14 μm band

Fig. 11. Comparison of the inversion results of three algorithms and actual values in the 3~5 μm band

Fig. 12. Comparison of the inversion results of three algorithms and actual values in the 8~14 μm band

Fig. 13. Reflection characteristic curve in 3~5 μm bands

Fig. 14. Reflection characteristic curve in 8~14 μm bands

Fig. 15. The reflected brightness envelope when the light source incidents vertically on the wall