Correlated imaging with macroscopic fields

We demonstrate analytically that correlated imaging in the regime of large photon number can be implemented using both a classical and an entangled source. The classically correlated beams are obtained by dividing thermal radiation by a beam splitter while entangled beams are obtained through parametric down-conversion. By treating the two system in parallel, a formal analogy is outlined between the two cases showing that classical beams can mimic qualitatively all the imaging features of the entangled beams. We also propose a method to improve substantially the imaging performances of correlated imaging which is based on homodyne detection combined with spatial averages.