Fig. 1. Iterative reconstruction method for measurement of OTF based on multi-frame images. (a) Experiment setup; (b) process schematic

Fig. 2. Schematic diagram for relative translations of points 1-3 to ideal point 0. (a) Uncorrected condition; (b) corrected condition

Fig. 3. Phase with 1.234 pixel translation in both x and y directions within cutoff frequency. (a) Ideal result; (b) PTF result after iterating once

Fig. 4. Simulated phase diagrams after introducing coma aberration. (a) PTF caused by coma aberration; (b) phase of random translation in image 1; (c) PTF result of image 1 after iterating once; (d) phase of random translation in image 2; (e) PTF result of image 2 after iterating once

Fig. 5. Comparison between theoretical phase difference and calculated phase difference. (a) PTF result of image 1 after iterating once; (b) PTF result of image 2 after iterating once; (c) ideal translation phase difference between image 1 and image 2; (d) calculated translation phase difference between image 1 and image 2

Fig. 6. Object pattern and captured image. (a) One of object patterns; (b) complete image corresponding to Fig. 6(a); (c) partial picture of object pattern; (d) partial picture corresponding to Fig. 6 (c)

Fig. 7. OTF measurement results by calculation. (a) Two-dimensional MTF; (b) two-dimensional PTF;(c) corrected MTF

Table 1. Mean square error between calculated PTF and ideal phase under diffraction limit

Table 2. Effects of correction and non-correction of relative translation on number of iterations and mean square error under different translations