Fig. 1. Schematic diagram of circular hole placed between sub-mirrors

Fig. 2. Theoretical circular diffraction patterns when piston error is varying from 1 μm to −1 μm at 400−700 nm bandwidth

Fig. 3. Theoretical circular diffraction patterns when piston error is varying from 250 nm to −250 nm at 400−700 nm bandwidth

Fig. 4. (a) Template pattern and (b) Corr2 as a function of piston errors when piston error is greater than visible coherence length

Fig. 5. (a) Template pattern and (b) Corr2 as a function of piston errors when piston error is within the coherence length of visible light

Fig. 6. Corr2 as a function of piston errors when R₁ is 0.2, 0.3 and 0.4

Fig. 7. Corr2 as a function of piston errors when R₂ is 0.3, 0.4 and 0.5

Fig. 8. Corr2 as a function of piston errors when SNR is 45, 60 and 90

Fig. 9. Corr2 as a function of piston errors when R₁=0.2, R₂=0.3, SNR=90 and R₁=0.3, R₂=0.3, SNR=90