Fig. 1. Turbulence image degradation model

Fig. 2. Image degradation simulation results in uniform turbulence

Fig. 3. The simulated and the theoretical MTFA changes with $r_{\mathrm{0}}$ in uniform turbulence

Fig. 4. Variation of simulated and theoretical values of isoplanatic angle with $r_{\mathrm{0}}$ in uniform turbulence

Fig. 5. Average correlation coefficient changes with point source separation angle

Fig. 6. Changes of the approximate invariant region of the image square with $r_{\mathrm{0}}$

Fig. 7. Schematic of turbulence extreme distribution

Fig. 8. Simulation results under two turbulence distributions

Fig. 9. Variation of mean MTFA and approximate invariant region of image square with $r_{\mathrm{0}}$ for two turbulence scenarios