Microwave holography

During the past 10 years microwave holography has been developed from an interesting extension of optical holography to a means of remote imaging with properties unique to this long-wavelength region of the electromagnetic spectrum. This review contains a concise derivation of the diffraction and communication theory of holography applied to the microwave regime and to small-scale imaging systems. Methods of recording microwave field distributions and reconstituting visible images are given with particular emphasis on digital image restoration and enhancement. Psychophysical aspects of image recognition are considered with other new developments. A wide range of possible applications are indicated including the remote imaging of concealed objects, subsurface probing, and antenna metrology.