Fig. 1. Overall architecture of the improved CycleGAN algorithm

Fig. 2. Generator G_VI of the improved CycleGAN algorithm

Fig. 3. Discriminator D_I of the improved CycleGAN algorithm

Fig. 4. Random paired data of dataset1. (a) Visible image; (b) Infrared image

Fig. 5. Random paired data of dataset2. (a) Visible image; (b) Infrared image

Fig. 6. Random paired data of dataset3. (a) Visible image; (b) Infrared image

Fig. 7. Comparison of test images of datasets1

Fig. 8. Detailed comparison of mountain peak details in the test image Fig. 7(a)

Fig. 9. Detailed comparison of ground surface details in the test image Fig.7(a)

Fig. 10. Detail comparison of the test image Fig.7(b)

Fig. 11. Comparison of test images of datasets2

Fig. 12. Detail comparison of the test image Fig.11(a)

Fig. 13. Comparison of test images of datasets3

Fig. 14. Detail comparison of the test image Fig.13(a)