  Digital holographic microscopy based on Gabor in-line holography is a
well-known method to reconstruct both the amplitude and phase of small objects.
To reconstruct the image of an object from its hologram, obtained under
illumination by monochromatic scalar waves, numerical calculations of Fresnel
integrals are required. To improve spatial resolution in the resulting
reconstruction, we re-sample the holographic data before application of the
reconstruction algorithm. This procedure amounts to inverting an interpolated
Fresnel diffraction image to recover the object. The advantage of this method
is demonstrated on experimental data, for the case of visible-light Gabor
holography of a resolution grid and a gnat wing.
