  We report the nonlocal imaging of an object by conditional averaging of the
random exposure frames of a reference detector, which only sees the freely
propagating field from a thermal light source. A bucket detector, synchronized
with the reference detector, records the intensity fluctuations of an identical
beam passing through the object mask. These fluctuations are sorted according
to their values relative to the mean, then the reference data in the
corresponding time-bins for a given fluctuation range are averaged, to produce
either positive or negative images. Since no correlation calculations are
involved, this correspondence imaging technique challenges our former
interpretations of "ghost" imaging. Compared with conventional correlation
imaging or compressed sensing schemes, both the number of exposures and
computation time are greatly reduced, while the visibility is much improved. A
simple statistical model is presented to explain the phenomenon.
