Fig. 1. Mach-Zehnder interferometric optical setup with optical path through smoke

Fig. 2. Simulation of smoke imaging effect. (a) Object to be imaged; (b) imaging through smoke

Fig. 3. Holograms and reconstructed images. (a) Smoke-free hologram; (b) through-smoke hologram; (c) reconstructed image without smoke; (d) reconstructed image through smoke field; (e) smoke-free -1 order image extraction result; (f) through-smoke -1 order image extraction result

Fig. 4. Algorithm flow chart

Fig. 5. Reconstructed image denoising. (a) BM3D denoising; (b) bilateral filtering denoising

Fig. 6. Target object extraction result. (a) Target object area; (b) segmented target object

Fig. 7. Results of shaded area segmentation. (a) Edge processing by Sobel operator; (b) image expansion; (c) image filling; (d) segmentation of shaded area

Fig. 8. Tent‐SSA algorithm flow chart

Fig. 9. Comparison between SSA algorithm and Tent‐SSA algorithm. (a) Convergence plot of objective function; (b) brightness deviation curve

Fig. 10. Processing results of proposed algorithm. (a) t=8 s reconstructed image; (b) t=10 s reconstructed image; (c) t=12 s reconstructed image; (d) t=8 s enhanced image; (e) t=10 s enhanced image; (f) t=12 s enhanced image; (g) t=14 s reconstructed image; (h) t=16 s reconstructed image; (i) t=18 s reconstructed image; (j) t=14 s enhanced image; (k) t=16 s enhanced image; (l) t=18 s enhanced image

Fig. 11. Comparison of effects of four algorithms. (a) t=8 s, algorithm in Ref. [19]; (b) t=8 s, algorithm in Ref. [22]; (c) t=8 s, CLAHE algorithm; (d) t=8 s, algorithm in this paper; (e) t=10 s, algorithm in Ref. [19]; (f) t=10 s, algorithm in Ref. [22]; (g) t=10 s, CLAHE algorithm; (h) t=10 s, algorithm in this paper; (i) t=12 s, algorithm in Ref. [19]; (j) t=12 s, algorithm in Ref. [22]; (k) t=12 s, CLAHE algorithm; (l) t=12 s, algorithm in this paper