Phase retrieval and twin-image elimination for in-line Fresnel holograms

Fourier phase-retrieval algorithms are modified and applied to in-line holography, where phase is lost during the hologram recording process. Retrieval of phase permits separation of real-object distributions from the twin-image interference that accompanies conventional optical reconstruction. The rate of convergence is enhanced by the availability of a good initial guess based on the digital equivalent of conventional optical reconstruction.