  In this paper we analyze an imaging technique based on intensity speckle
correlations over incident field position proposed in [J. A. Newmann and K. J.
Webb, Phys. Rev. Lett. 113, 263903 (2014)]. Its purpose is to reconstruct a
field incident on a strongly scattering random medium. The thickness of the
complex medium is much larger than the scattering mean free path so that the
wave emerging from the random section forms an incoherent speckle pattern. Our
analysis clarifies the conditions under which the method can give a good
reconstruction and characterizes its performance. The analysis is carried out
in the white-noise paraxial regime, which is relevant for the applications in
optics that motivated the original paper.
