  Group-theoretical analysis of arbitrary polarization devices is performed,
based on the theory of the Lorentz group. In effective "non-relativistic"
Mueller case, described by 3-dimensional orthogonal matrices, results of the
one polarization measurement determine group theoretical parameters within the
accuracy of an arbitrary numerical variable. There are derived formulas,
defining Muller parameter of the non-relativistic Mueller device uniquely and
in explicit form by by the results of two independent polarization
measurements. Analysis is extended to Lorentzian optical devices, described by
4-dimensional Mueller matrices.
