Fig. 1. Development of advanced night vision imaging equipment

Fig. 2. Development stages of photoelectron multiplication mechanism of low-light level night vision devices

Fig. 3. Mathematical modeling of forward physical imaging processes and reconstruction of images with the help of constructive imaging methods

Fig. 4. Experimental results of negative dB signal reconstructive technique. (a) The original image of the checkerboard in the darkroom with an SNR of −10.03 dB; (b) The reconstructive image of the checkerboard in the darkroom with an SNR of 0.492 dB; (c) The original image of the mountain forest with an SNR of −5.3 dB; (d) The reconstructive image of the mountain forest with an SNR of 6.99 dB

Fig. 5. Scene based "passive" IR image nonuniformity correction

Fig. 6. Nyquist sampling limit imposed by detector pixel size (mosaic effect). Under-sampling (large pixel size) leads to spectral aliasing

Fig. 7. Diffraction resolution limit limited by the aperture of optical system (Airy spot). (a) The minimum resolvable distance (optical angular resolution) of the imaging system is inversely proportional to the aperture of the imaging system; (b)-(d) Airy spot images of two incoherent point targets at different distances

Fig. 8. Principle of coded aperture pixel super-resolution imaging. (a) Schematic diagram of optical path structure of imaging system; (b) The point spread function modulated by coded aperture is compared with the traditional fixed aperture imaging; (c) Distribution of optical transfer function and point spread function under different patterns; (d) Frequency domain aliasing caused by the insufficient spatial sampling of the detector and demodulated image after coded aperture constructive imaging

Fig. 9. Typical experimental results of coded aperture-based pixel super-resolution imaging technique. (a) Long-wave infrared imaging system for standard resolution target imaging test; (b)-(d) Comparison of imaging resolution before and after applying pixel super-resolution algorithm on USAF target and vehicle results

Fig. 10. Principle of incoherent synthetic aperture technology. (a) Process for synthetic aperture super-resolution imaging; (b) Point spread function optimization based on time and aperture division synthetic aperture of phase reconstructive; (c) Image comparison before and after super resolution

Fig. 11. Experimental equipment and imaging results of incoherent super-resolution imaging technology. (a) Experiment setup of the incoherent synthetic aperture; (b) Spectrum scanning expansion based on Fourier ptychography; (c) Single-aperture self-correlation wavefront restoration based on PZT phase-shifting; (d) Single-aperture self-correlation imaging and details; (e) Incoherent synthetic aperture super-resolution imaging and details, achieving super-resolution imaging corresponding to 4 times diffraction limit of the optical system