Improvement in visibility of an in-focus reconstructed image in digital holography by reduction of the influence of out-of-focus objects

When a reconstruction is performed on a digital holographic image that contains small objects at different depths, diffraction that is due to out-offocus objects disrupts the visibility of the nearby focused objects. We propose a method to substitute for focused object amplitudes other amplitudes that will reduce propagation diffraction effects when other depths are investigated. The replacement amplitudes are computed by use of an algorithm that reduces the highest spatial frequencies of the resultant image. The theoretical aspects of the method are presented, and results for simulated and experimental examples are shown.