Fig. 1. Diagram of SRCNN network structure

Fig. 2. Diagram of VDSR network structure

Fig. 3. Network structural diagram of proposed algorithm

Fig. 4. Jumping cascade block

Fig. 5. Visualization results of picture butterfly after 4-time magnification. (a) Low-level feature; (b) hopping cascade feature; (c) reconstructing feature

Fig. 6. Relationship between average PSNR of different layers with number of iterations under Set5 test set

Fig. 7. Relationship between iteration times and average PSNR of different network structures under Set5 test set

Fig. 8. Relationship between average PSNR of different activation functions with number of iterations under Set5 test set

Fig. 9. Relationship between average PSNR of different filter numbers with number of iterations under Set5 test set

Fig. 10. Relationship between run time and average PSNR of different methods under Set5 test set

Fig. 11. Comparison of butterfly images obtained by different algorithms

Fig. 12. Comparison of PPT obtained by different algorithms

Fig. 13. Comparison of man images obtained by different algorithms