Fig. 1. Flowchart of the algorithm

Fig. 2. Sky region segmentation.(a) Hazy image; (b) brightness component; (c) rough segmentation result; (d) fine segmentation result

Fig. 3. Experimental comparison of fusion dark channel and dark channel of different sizes. (a) Hazy image; (b) weight map; (c) fusion dark channel; (d) small-size dark channel restoration image; (e) large-size dark channel restoration image; (f) fusion dark channel restoration image

Fig. 4. Transmission combining and refining effect. (a) Hazy image; (b) edge detection graph; (c) transition zone; (d) rough transmission; (e) fine transmission; (f) fog-free image

Fig. 5. Comparison of experimental results obtained by different algorithms.(a) Hazy image; (b) method in Ref. [11]; (c) method in Ref. [13]; (d) method in Ref. [14]; (e) method in Ref. [15]; (f) our algorithm

Fig. 6. the objective experimental results. (a) Percentage of saturated pixels; (b) increasing rate of visible edges; (c) average gradient; (d) average running time