  The phasor field has been shown to be a valuable tool for non-line-of-sight
imaging. We present a formal analysis of phasor-field imaging using paraxial
wave optics. Then, we derive a set of propagation primitives---using the
two-frequency, spatial Wigner distribution---that extend the purview of
phasor-field imaging. We use these primitives to analyze a set of simple
imaging scenarios involving occluded and unoccluded geometries with modulated
and unmodulated light. These scenarios demonstrate how to apply the primitives
in practice and reveal what kind of insights can be expected from them.
