Fig. 1. Schematic diagram of coding-aperture imaging

Fig. 2. Point spread function and neighbourhood weight coefficients of the potential function at 3 times the samples

Fig. 3. Too small a neighbourhood range results in lower hotspot values

Fig. 4. Schematic diagram of the penalty coefficient calculation method

Fig. 5. Schematic and photograph of the coded-aperture gamma camera

Fig. 6. Diagram of Monte Carlo simulation

Fig. 7. System response matrix (484×961)

Fig. 8. Experimental platform for precision imaging of γ sources

Fig. 9. MLEM and MAP reconstruction images of ²²Na point source with increasing iterations

Fig. 10. 2D slices of MLEM and MAP reconstructed images for a ²²Na point source with increasing iterations

Fig. 11. Comparison of the mean gradient values and CNRs of reconstructed images using MLEM and MAP algorithms at 300, 500, 800, and 1200 iterations

Fig. 12. Comparison of the reconstruction results of multipoint ²²Na sources using MLEM, 3×3 neighbourhood MAP and 5×5 neighbourhood MAP algorithms with the same parameters (δ = 0.003, β = 0.03, 500 iterations)

Fig. 13. 2D slices of the MLEM reconstructed image and the MAP reconstructed image when using the L1, L2, and Huber potential functions, respectively, for the same radiation source

Fig. 14. Comparison of the effectiveness between the MLEM and the MAP algorithms when imaging at long distances

Fig. 15. Comparison of the effectiveness between the MLEM and MAP algorithms in a confined environment with disturbance sources