Radio wave holography is useful for imaging and diagnostics but it has time delays. Data acquisition is slow if an antenna is mechanically scanned; this delay can be eliminated with a receptor array. Additional delays arise in acquiring and processing data. For example, visible light reconstruction requires producing scale-reduced replicas of holograms. Digital reconstruction has delays in analog-to-digital conversion and in computation. These delays are undesirable for real-time imaging, say of transient events or scenes. This paper demonstrates a method for real-time wavefront reconstruction and presents two implementations. We start with previously formed microwave holograms, and reconstruct first with an infrared radiation and then with millimeter waves. Two reconstruction wavelengths were utilized because of our interest in scaling between formation and reconstruction.
J. T. Nilles,
E. L. Rope,
"Spatially Non-Coherent Processing With Infrared Or Millimeter Waves", Proc. SPIE 0963, Optical Computing '88, (8 February 1988); doi: 10.1117/12.947908; https://doi.org/10.1117/12.947908