Fig. 1. Schematic of the light field microscopic imaging (f_o, f_t and f_μ are the focal length of the objective lens, the tube lens and the microlens, respectively)

Fig. 2. Schematic of the light field Micro-PIV system (L_l is the flange distance of C lens mount)

Fig. 3. Schematic of the light field microscopic imaging and the deconvolution reconstruction for micro-scale flow

Fig. 4. Imaging process of a point light source in light field microscopic imaging system

Fig. 5. PSFs of the light field microscopic imaging system obtained by calculation at different depths

Fig. 6. Photography of the experimental system

Fig. 7. Assembled cage light field camera system. (a) Schematic; (b) photography

Fig. 8. PSFs of the light field microscopic imaging system obtained by experiments at different depths

Fig. 9. V_SSIM evaluation of PSFs calculated based on wave optics theory and obtained by experiment

Fig. 10. Reconstructed particle at z=40 μm. (a) Reconstructed tracer particle light intensity distribution; (b) front view; (c) side view

Fig. 11. Variation of the length of elongation with the defocusing distance (R_x and R_z are the results of theoretical calculation, and R_xe and R_ze are the results of experiments)

Fig. 12. Variation of the reconstructed position error with the defocusing distance

Fig. 13. Light field image of the tracer particles and reconstruction by simulation at particle concentration of 2.75×10⁷ cm^-3. (a) Light field image of tracer particles; (b) reconstructed tracer particles

Fig. 14. Reconstructed position errors of tracer particles at x and y directions

Fig. 15. Reconstructed position errors of tracer particles at z direction

Fig. 16. Light field images and reconstructed tracer particles by experiments. (a)(c) Light field images obtained at particle concentration of 2.75×10⁶ cm^-3 and 2.75×10⁷ cm^-3, respectively; (b)(d) reconstructed tracer particles at particle concentration of 2.75×10⁶ cm^-3 and 2.75×10⁷ cm^-3, respectively