The work would be useful for specialists in the field of ellipsometry and engineers engaged in the task of measuring the rough surface and of determination of properties of inhomogeneous structures or films, such as: polymorphous oxides of titanium or vanadium, silicon nitride after oxidation, growth defects of MBE film. The work would be useful for all who wish to improve the quality of desired parameter estimation; provided that experimenter uses the new algorithm of minimization procedure with statistical analysis of a set of found solutions and step-by-step variation of the simplex boundaries which restrict the domain of desired values.