A physiologic facsimile image of a biological target is obtained by: scang the target by transmitting a microwave signal through the target and measuring at least one of the amplitude and phase components of the complex microwave power transmission coefficient at each one of a plurality of sample locations which are spaced so as to define a two-dimensional array and such that a set of digital data for each of the measured components is obtained, and for at least one of the sets of data; sorting the set of data into column order; magnifying data derived from the sorting step so as to enhance the resolution of the image; mapping data derived from the magnifying step into further data using a predetermined mapping function so as to enhance the contrast between selected portions of the image; and obtaining the set of control signals by filtering data derived from the mapping step using a band pass function which rejects spatial frequencies below a predetermined first frequency and/or rejects spatial frequencies above a predetermined second frequency so as to minimize, respectively, the effects of variations in the thickness of the target and/or spurious frequencies resulting from the magnifying step.