Fig. 1. Image acquisition schematic of phase diversity method combined with defocusing grating

Fig. 2. Flow chart of HPSO algorithm

Fig. 3. Extended object and focal plane and defocusing plane images after passing through optical system. (a) Extended object; (b) focal plane image; (c) defocusing plane image

Fig. 4. Focal and defocusing images containing aberrations. (a) Focal image; (b) defocusing image

Fig. 5. Simulated wavefront. (a) Loaded wavefront; (b) restored wavefront; (c) wavefront residual

Fig. 6. Iteration curve of HPSO algorithm

Fig. 7. Line chart of wavefront residual mean value for different aberration

Fig. 8. Line charts of wavefront residual of HPSO algorithm and SPGD algorithm when the RMS value of aberration is 0.144λ