Reconstructing the density operator by using generalized field   quadratures
  The Wigner function for one and two-mode quantum systems is explicitely expressed in terms of the marginal distribution for the generic linearly transformed quadratures. Then, also the density operator of those systems is written in terms of the marginal distribution of these quadratures. Some examples to apply this formalism, and a reduction to the usual optical homodyne tomography are considered. 
G. M. D'Ariano, S. Mancini, V. I. Man'ko and P. Tombesi