1. A method in an apparatus for measuring optical anisotropic properties of a material, comprising: measuring a Mueller matrix of the material at a first angle; determining the diattenuation orientation of the material based on the measured Mueller matrix at the first angle; rotating the material to a second angle; measuring a Mueller matrix of the material at the second angle; determining the diattenuation orientation of the material based on the measured Mueller matrix at the second angle; storing a data set of the determined diattenuation orientations and the first and second angles; curve fitting a formula to the stored data set of determined diattenuation orientations and the first and second angles to determine fitting parameters, wherein the formula is: 
 P=A+B sin(2θ+φ B )+ C sin(θ+φ C ) and wherein P is the diattenuation orientation, θ is a rotational angle of the material, B is proportional to the anisotropic magnitude of the material, and φ B is the anisotropy orientation of the material; and determining anisotropic orientation and a value proportional to anisotropic magnitude of the material using the determined fitting parameters; and repeatedly performing; (1) rotating the material to a different angle, (2) measuring a Mueller matrix of the material at the different angle, and (3) determining the diattenuation orientation of the material based on the measured Mueller matrix at the different angle.