Foggy Scene Rendering Based on Transmission Map Estimation

Table 1

International visibility grades with their medium extinction coefficients.

Grade	Weather	Visibility distance	Extinction coefficient
0	Dense fog	<50 m	>78.2
1	Thick fog	50–200 m	78.2–19.6
2	Moderate fog	200–500 m	19.6–7.82
3	Light fog	500 m–1 km	7.82–3.91
4	Thin fog	1 km-2 km	3.91–1.96
5	Haze	2 km–4 km	1.960–0.954
6	Light haze	4 km–10 km	0.954–0.391
7	Clear	10 km–20 km	0.391–0.196
8	Very clear	20 km–50 km	0.196–0.078
9	Extremely clear	>50 km	0.0141