Radiometric sensing of biological layered media

Abstract

The retrieval of temperature profiles in layered living tissues from microwave radiometric measurements is considered. The brightness temperature of a layered biological structure is expressed as a function of the thermal distribution in the tissues for different microwave frequencies, angles of observation, and polarization of the emitted waves. A “coherent” approach to the radiative transfer problem is followed to obtain the weighting functions in closed form for use in the inverse problem. Finally, the extraction of the thermal profiles from brightness data sets by use of Kalman filtering is discussed, with particular reference to the detectability of deep thermal anomalies.