Fig. 1. Optical imaging systems. (a) Schematic diagram of direct imaging technology based on lenses (groups); (b) schematic diagram of lensless optical computational imaging system

Fig. 2. Partial minimalist lensless imaging systems. (a) Hyperspectral camera based on electrochromic device^[12]; (b) programmable Fresnel zone aperture (FZA) lensless camera^[13]; (c) Bio-FlatScope^[14]; (d) Bio-FlatScopeNHP^[15]; (e) full-Stocks polarization lensless camera^[16]; (f) FZA-based lensless camera^[17]

Fig. 3. Examples of applying the lensless imaging systems to biological experiments. (a) Schematic diagram and reconstructed image of Bio-FlatScope applied to freely running mice with fixed heads, and comparison test results of Bio-FlatScope and epifluorescence microscope^[14]; (b) imaging results of Bio-FlatScopeNHP applied to monkey brains observation with fixed and unrestricted heads^[15]

Fig. 4. Applications of lensless multi-modality imagings. (a) Temporal compressive edge detection imaging^[46]; (b) gesture recognition^[13]; (c) computational spectrometry^[47]; (d) light-field imaging^[48]; (e) full-Stocks polarization imaging^[16]; (f) multi-spectral imaging^[17]; (g) three-dimensional imaging^[49]; (h) high-resolution imaging^[33]; (i) hyper-spectral imaging^[50]

Fig. 5. Applications of hypersurface modulation in lensless imaging systems. (a) Ultra-compact snapshot spectral light-field imaging^[63]; (b) passive single-shot four-dimensional imaging^[64]

Fig. 6. Applications of lensless imaging systems for data security. (a) Image encryption^[78]; (b) privacy classification protection^[83]

Fig. 7. Representative works of imaging under special wavebands or low-light conditions. (a) Lensless ghost imaging with sunlight^[95]; (b) fast first-photon ghost imaging^[96]; (c) photon-limited single pixel imaging^[97]; (d) X-ray ghost imaging^[91]; (e) terahertz microscopy via nonlinear ghost imaging^[92]; (f) ultraviolet ghost imaging^[89]

Fig. 8. Partial intelligent reconstruction algorithms. (a) Quantum deep generative prior^[106]; (b) quantum neural network circuit structure^[107]; (c) implicit neural space-time network^[108]; (d) forward model-driven untrained deep network^[109]

Fig. 9. Reconstruction results via intelligent algorithms. (a) Implicit neural space-time network^[108]; (b) quantum deep generative prior^[106]

Fig. 10. Lensless systems based on optical diffraction neural networks. (a) All-optical machine learning^[117]; (b) computer-less all-light imaging^[116]; (c) lensless convolutional optical processor^[118]; (d) imaging through multimode fibers^[125]