Developments in Microwave Holographic Imaging

The evolution of microwave imaging is traced from its origin as a primitive analogue of optical holography to its present stage as a diagnostic imaging technique in its own right. The essential operations comprising data acquisition, data processing and display are described in terms of techniques in current use. New results from two applications which. have already demonstrated some potency - reflector antenna aperture and profile measurements and the imaging of sub-surface pipes and cables - are given. Recent approacges to microwave data processing including superresolution, `in-line´ holography, and three-dimensional image construction, are also presented.