Fig. 1. OSH system. BS, beam splitter; AOFS, acousto-optic frequency shifter; M, mirror; p(x,y), pupil; L, lens; PD, photodetector; BPF, bandpass filter; LPF, low-pass filter.

Fig. 2. The Lissajous curve and the selected test positions.

Fig. 3. (a) The generated hologram; (b) the first 50 eigenvalues.

Fig. 4. The sum of the pseudo-spectrum along the z axis, with target at (a) (10,6) and (b) (30,10).

Fig. 5. The sum of the pseudo-spectrum along the z axis. (a) Frequency ratio p∶q = 13∶21 or p∶q = 23∶11; (b) phase difference ϕ = 0 or ϕ = π.

Fig. 6. (a) The first 50 eigenvalues of TR matrix; (b) the sum of the pseudo-spectrum along the z axis.

Fig. 7. (a) The first 50 eigenvalues of TR matrix; (b) the sum of pseudo-spectrum of each layer along the z axis.

Fig. 8. The sum of pseudo-spectrum of each layer along the z axis.

Fig. 9. The sum of pseudo-spectrum along the z axis. (a) z₁ = 30 mm, z₂ = 31.5 mm, (b) z₁ = 50 mm, z₂ = 51.5 mm, (c) z₁ = 70 mm, z₂ = 71.5 mm.

Fig. 10. The sum of pseudo-spectrum along the z axis. (a) λ = 405 nm, (b) λ = 780 nm, (c) λ = 980 nm.

Fig. 11. The relationship between SNR and resolution.

Fig. 12. Complex objects (a) at z₁ = 30 mm and (b) at z₂ = 35 mm.

Fig. 13. (a) The generated hologram; (b) the eigenvalues of TR matrix.

Fig. 14. The proposed method is compared with various positioning methods. (a) Entropy minimization; (b) TR-MUSIC based on diagonal elements.

Fig. 15. The recorded hologram. (a) Real part; (b) imaginary part.

Fig. 16. (a) Eigenvalues of TR matrix; (b) parameters calculated along the z axis obtained by different methods.

Fig. 17. Reconstructed image at (a) z₁ and (b) z₂.