Fig. 1. (a) The larger the variance of the normal direction of the micro surface, the rougher the macro surface; (b) The smaller the variance of the normal direction of the micro surface, the smoother the macro surface

Fig. 2. Schematic diagram of Oren-Nayar model

Fig. 3. Hyperspectral LiDAR system. (a) Composition diagram of hyperspectral LiDAR system; (b) Principle prototype of hyperspectral LiDAR

Fig. 4. Experimental sample. (a) White paper; (b) Floor tiles; (c) Concrete; (d) Gypsum; (e) Orthoclase; (f) Silica; (g) Granite; (h) Griotte

Fig. 5. Schematic diagram of distance effect experiment

Fig. 6. Incident angle effect of backscatter intensity of hyperspectral LiDAR at different wavelengths. (a) White paper; (b) Floor tiles; (c) Concrete; (d) Gypsum; (e) Orthoclase; (f) Silica; (g) Granite; (h) Griotte

Fig. 7. Scatter plot and Lambertian model fitting curve of backscatter intensity (650 nm). (a) Floor tiles; (b) Concrete

Fig. 8. Distance effect of backscatter intensity of 100% diffuse reflective whiteboard at different wavelengths. (a) The curve of the backscatter intensity varying with R; (b) Curve of backscatter intensity varying with \begin{document}$ 1/{R}^{2} $\end{document}

Fig. 9. Distance effect of backscatter intensity of 70% diffuse reflective whiteboard at different wavelengths. (a) The curve of the backscatter intensity varying with R; (b) Curve of backscatter intensity varying with \begin{document}$ 1/{R}^{2} $\end{document}

Fig. 10. Calculation results of \begin{document}$ {\sigma }\left({\lambda }\right) $\end{document} of different samples of Oren-Nayar model

Fig. 11. Backscatter intensity of different wavelengths after correction of Oren-Nayar model. (a) White paper; (b) Floor tiles; (c) Concrete; (d) Gypsum; (e) Orthoclase; (f) Silica; (g) Granite; (h) Griotte

Fig. 12. Reflectance comparison of different incident angles before and after correction of concrete. (a) Before correction; (b) After correction of Lambert model; (c) After correction of Oren-Nayar model

Fig. 13. Standard deviation of reflectance at different incident angles. (a) White paper; (b) Floor tiles; (c) Concrete; (d) Gypsum; (e) Orthoclase; (f) Silica; (g) Granite; (h) Griotte