Criteria for objects suitable for reconstruction from holograms and diffraction patterns

In this study, quantitative criteria for reconstruction of objects from their hologram and diffraction patterns, and in particular for the phase objects in digital holography, are derived. The criteria that allow distinguishing the hologram and diffraction pattern are outlined. Gabor derived his criterion for objects suitable for holography based on the condition that the background in the reconstructed object's distribution should be nearly flat so that its intensity contrast does not exceed 0.05.According to Gabor, an opaque object is suitable for holographic reconstruction if it occupies no more than 0.01 of the imaged area, and a phase-shifting object cannot be reconstructed in principle. We revisit these criteria and show that both types of objects can be reconstructed when the object occupies less than 0.01 of the total illuminated area. In addition, a simplified derivation of the criteria is provided that is based on the use of Parseval's theorem, and it is shown that in general, objects (including amplitude-only and phase-only) can be reconstructed at signal-to-noise ratio of 10 or higher, provided the object occupies less than 0.005 of the total illuminated area. In addition, a simplified derivation of the criteria is provided that is based on Parseval's theorem. It is shown that for objects reconstructed from their holograms and the twin image treated as noise, the signal-to-noise ratio of 10 or higher can be achieved provided the object occupies less than 0.005 of the total illuminated area When a hologram is reconstructed by applying iterative algorithms, the requirement for the object size is much more generous and identical to that applied in coherent diffraction imaging: any type of object (amplitude-only, phase-only, or amplitude-and-phase mixed properties) is suitable for holography when the object's size in each dimension is less than half of the probed region's extent.