Fig. 1. Two-pupil heterodyne scanning image processor.

Fig. 2. Electronic demodulation system (⊗ is electronic multiplier).

Fig. 3. (a) Original object and (b) its logarithmic magnitude spectrum.

Fig. 4. (a) |OTF| [fx and fy are spatial frequencies in unit of 1/mm] and (b) reconstructed image of single-offset SPP with 5 mm shift in the horizontal direction. (c) and (d) Output images of the single-offset SPP with different shift directions.

Fig. 5. (a) and (b) |OTF| and the reconstructed image of the two-offset SPP pupil with same charge and 5 mm shift. (c) and (d) |OTF| and the reconstructed image of the two-offset SPP pupil with same charge and 2.5 mm shift.

Fig. 6. Comparison of the edge extracted images of a square object using (a) single-offset SPP and (b) two-offset SPPs.

Fig. 7. (a) |OTF| and (b) reconstructed image of the two-offset SPPs as a pupil with opposite charges and 2.5 mm shift, (c) |OTF| and (d) reconstructed image of the two-offset SPPs as a pupil with opposite charges in the vertical direction.

Fig. 8. Improved |OTF| and the reconstructed images of the two-offset SPPs as a pupil with opposite charges in the form of Eq. (11), and φ0 is (a) and (b) 3π/4 and (c) and (d) π/2.