In this paper we present a theoretical model describing the real images replayed from finite aperture Fraunhofer holograms of two identical co-planar objects. We have solved numerically the resulting image equations for the case of two circular disc objects, and compare our predictions with experimental measurements from in-line Fraunhofer holograms recorded on silver-halide emulsions. Three measurement criteria for calculating the disc diameters and separation are described, and their errors discussed. It is found experimentally that a criterion based on average intensity results in the smallest errors due to its insensitivity to the effects of coherent noise.
Peter R. Hobson,
"Finite aperture Fraunhofer holograms of two coplanar discs", Proc. SPIE 1732, Holographics International '92, (2 March 1993); doi: 10.1117/12.140459; https://doi.org/10.1117/12.140459