Fig. 1. Schematic diagram of obstacles at different locations in pre-modulated SPI system

Fig. 2. Schematic diagram of ring slit forming scanning Bessel beam. (a) Optical path diagram; (b) annular slit diagram; (c) Bessel distribution intensity diagram and intensity distribution curve in x direction formed by annular slit behind lens; (d) displacement diagram of annular slit in certain direction; (e) corresponding Bessel beam scanning diagram

Fig. 3. Schematic diagram of scanning Bessel beam obtained by DMD. (a) Schematic diagram of optical path from DMD plane to object plane; (b) x-z plane intensity distribution of Bessel beam

Fig. 4. Bessel-SPI simulation results. (a) Object image; (b1)‒(e1) Bessel beam illumination areas obtained by different Δs; (b2)‒(e2) Bessel-SPI results obtained from different Δs

Fig. 5. Imaging results of SPI without obstacles. (a) Original image of object; Bessel-SPI imaging results when (b) N=600, (c) N=900, and (d) N=1200; Hadamard-SPI imaging results when (e) N=600, (f) N=900, and (g) N=1200

Fig. 6. Optical path under center occluded type obstacle. (a) Schematic diagram of Bessel beam self-reconstruction after obstacle; (b) obstacle shape

Fig. 7. Influences of center-occluded obstacles on Bessel-SPI. (a) xz intensity distribution of beam when obstacles are located at different z₁ positions; (b1)‒(b5) intensity illuminated on object and (b6)‒(b10) corresponding Bessel-SPI results when z=12 cm; (c1)‒(c5) intensity illuminated on object and (c6)‒(c10) corresponding Bessel-SPI results when z₂=11 cm

Fig. 8. Effects of off-axis central occlusion type obstacles on reconstruction results of Bessel-SPI. (a) Obstacle diagram; (b)‒(f) Bessel intensity illuminated on object; (g)‒(k) corresponding Bessel-SPI reconstruction images

Fig. 9. Optical path diagram under occlusion of surrounding obstacle. (a) Bessel beam self-reconstruction diagram of light field behind obstacle; (b) obstacle shape

Fig. 10. Effects of peripheral occlusion type obstacles on reconstruction results of Bessel-SPI. (a) Intensity distribution in xz plane of beam when obstacles are located at different z₁ positions; (b1)‒(b5) intensity illuminated on object and (b6)‒(b10) corresponding Bessel-SPI results when the object is fixed at z=12 cm

Fig. 11. Effects of off-axis peripheral occlusion type obstacles on reconstruction results of Bessel-SPI. (a) Obstacle diagram; (b)‒(f) Bessel intensity illuminated on object; (g)‒(k) corresponding Bessel-SPI reconstruction results

Fig. 12. Comparison of imaging results between Bessel-SPI and Hadamard-SPI for occluded object. (a)(b) Distributions of intensities of Bessel beams illuminated on object with and without obstacle; (c)‒(e) Bessel-SPI reconstruction images for different N; (f)(g) distributions of Hadamard modes illuminated on object with and without obstacle; (h)‒(j) Hadamard-SPI reconstruction results for different N

Fig. 13. Diagram of experimental light path

Fig. 14. Diagram of experimental optical path. (a) Diagram of light path between DMD and object; (b) intensity distribution of Bessel beam without obstacle; (c)‒(g) intensity distributions of beam illuminated on object when z₁=2 cm and z₂ are 5, 14, 48, 72 and 120 cm respectively

Fig. 15. Experimental results of Bessel-SPI. (a) Object image; (b) obstacle; (c)‒(f) Bessel-SPI results for object without obstacle; (g)‒(j) Bessel-SPI results for occluded object when z₁=2 cm and z₂=58 cm; (k)‒(n) Bessel-SPI results for occluded object when z₁=2 cm and z₂=120 cm