  Here we present practical methods for simulation and reconstruction of
in-line digital holograms recorded with plane and spherical waves. The
algorithms described here are applicable to holographic imaging of an object
exhibiting absorption as well as phase shifting properties. Optimal parameters,
related to distances, sampling rate, and other factors for successful
simulation and reconstruction of holograms are evaluated and criteria for the
achievable resolution are worked out. Moreover, we show that the numerical
procedures for the reconstruction of holograms recorded with plane and
spherical waves are identical under certain conditions. Experimental examples
of holograms and their reconstructions are also discussed.
