Exploration of the Rayleigh roughness in THz medical imaging

Summary form only given. The effect of rough surface scattering on the contrast observed in THz medical imaging is explored. A Frequency Modulated Continuous Wave (FMCW) THz imaging system operating at a center frequency of 650 GHz with a time averaged bandwidth varied between ~ 0.01% and 1% bandwidth was used to image rough surface targets to explore the effect of rough surface scattering on the contrast observed in THz medical imaging. In addition to the commonly characterized expected power reflected in the specular direction we also ascertained the variance (second moment) of the power and computed the observed signal to clutter ratio (SCR). The results fit well to standard Rayleigh roughness theory and confirm that operating THz imaging systems at moderate incidence angles offer a significant increase in SCR at the minimal cost of spatial resolution.