Multilevel computer-processed displays of small concealed objects remotely imaged by microwave holography

High-definition microwave images of small objects are displayed. Image reconstitution, achieved by computer processing and printout on electrically sensitive paper, is seen to be superior to coherent optical processing of microwave holograms. It is shown that dielectric, as well as conducting, scatterers can be imaged through low-loss concealing media, and that concealed objects can also be recognised through rough surfaces.