Passive Millimeter Wave Systems often have low spatial resolution which limits the size of detectable objects.
However, there are some special cases in which objects that do not completely fill a pixel may be readily detected. The
geometry of wires and pipes make them particularly visible, although the contrast can vary rapidly with detector - target
geometry. In this paper a model is developed for the contrast of a reflective cylinder against an arbitrary background.
Experimental data is presented from a high clutter environment that shows sub pixel detection in practical