Fig. 1. Spectrum of “Cameraman” image with the resolution of $\mathrm{64}\times \mathrm{64}$

Fig. 2. Flow of DQN-SPI

Fig. 3. The reconstructed "Cameraman" images using different down-sampling strategies at different sampling ratios

Fig. 4. The spectrum of the reconstructed "Cameraman" images using different down-sampling strategies at different sampling ratios

Fig. 5. Reconstruction at low sampling ratios

Fig. 6. $S(k)$ curve of DSPI，FSPI，HSPI and KMSPI

Fig. 7. Schematic of the experimental setup

Fig. 8. The reconstructed images of "tortoise" using different down-sampling strategies at different sampling ratios