Structure profiles from optical interferometric data can be identified by
obtaining a plurality of broadband interferometric optical profiles of a
structure as a function of structure depth in an axial direction. Each of
the plurality of interferometric optical profiles include a reference
signal propagated through a reference path and a sample signal reflected
from a sample reflector in the axial direction. An axial position
corresponding to at least a portion of the structure is selected. Phase
variations of the plurality of interferometric optical profiles are
determined at the selected axial position. A physical displacement of the
structure is identified based on the phase variations at the selected
axial position.