In
mathematics,
integral geometry is the theory of
measures on a geometrical space invariant under the
symmetry group of that space. In more recent times, the meaning has been broadened to include a view of invariant (or
equivariant) transformations from the space of functions on one geometrical space to the space of functions on another geometrical space. Such transformations often take the form of
integral transforms such as the
Radon transform and its generalizations.