Fig. 1. Flowchart of the proposed algorithm

Fig. 2. Atmospheric light and dehazed results based on different methods. (a) Input image; (b) atmospheric light of Ref. [7] method; (c) dehazed result of Ref. [7] method; (d) atmospheric light of Ref. [14] method; (e) dehazed result of Ref. [14] method; (f) low-pass filtering of proposed method; (g) atmospheric light of proposed method; (h) dehazed result of proposed method

Fig. 3. Mapping relationship between input image and output image

Fig. 4. Dehazed results based on different transmittances. (a) Input image; (b) t=0.1; (c) t=0.5; (d) t=0.9

Fig. 5. Estimation and optimization of transmittance. (a) Original image; (b) initial transmittance; (c) optimized transmittance; (d) dehazed image

Fig. 6. Color correction of nighttime image by different methods. (a1)(a2) Original images; (b1)(b2) corrected images by Shade of Gray[20] method; (c1)(c2) corrected images by White balance[21] method; (d1)(d2)corrected images by proposed method

Fig. 7. Dehazed results of different methods. (a1)(a2) Input nighttime images; (b1)(b2) results of Retinex method; (c1)(c2) results of histogram equalization method; (d1)(d2) results of proposed method

Fig. 8. Dehazed results of different methods for Pavilion. (a) Pavilion image; (b) result of Ref. [7] method; (c) result of Ref. [12] method; (d) result of Ref. [14] method; (e) result of proposed method

Fig. 9. Dehazed resultsof different methods for Train. (a) Train image; (b) result of Ref. [7] method; (c) result of Ref. [12] method; (d) result of Ref. [14] method; (e) result of proposed method

Fig. 10. Dehazed results of different methods for Building. (a) Building image; (b) result of Ref. [7] method; (c) result of Ref. [12] method; (d) result of Ref. [14] method; (e) result of proposed method

Fig. 11. Dehazed results of different methods for Street. (a) Street image; (b) result of Ref. [7] method; (c) result of Ref. [12] method; (d) result of Ref. [14] method; (e) result of proposed method

Table 1. Comparison of K/C of different methods