Wavefront reconstruction for in-line holograms formed by pure amplitude objects

A recursive algorithm is described which gives a numerical solution to the twin image problem of in-line holography for pure amplitude objects. This a lgorithm combines the benefits of the Fraurahofer method and the Gerchberg- Saxton type algorithm, so that the applicability is extended to include fea tures whose Fresnel numbers are significantly larger than one. A solution t o the wavefront reconstruction problem from a single hologram formed by a g eneral object is found to be impossible, due to non-uniqueness of the solut ion. (C) 1999 Published by Elsevier Science B.V. All rights reserved.