Digital in-line holographic techniques for long wavelength imaging

In-line holography involves a very simple data recording procedure. However, the image obtained from the in-line hologram suffers from a high degree of interference with the unwanted holographic outputs. The proposed techniques of digital image reconstitution provide convenient solutions to this problem compared to those attempted in optics. Various techniques for suppressing the interfering holographic outputs are given. In particular, the feasibility of using the volume hologram principle to reduce the twin image and autocorrelation interferences is demonstrated. Experimental validations are given at microwave and ultrasonic frequencies.