Phase retrieval of photon-limited stellar images from information of the power spectrum only

We have obtained reconstructions of photon-limited stellar images by using iterative phase-retrieval methods. These procedures operate with the autocorrelation or, equivalently, power-spectrum data that are estimated by applying stellar speckle interferometry techniques to turbulence-degraded, short-exposure specklegrams. We present results from both real data and computer-simulated data. We also compare these results according to the phase-retrieval algorithm used and address whether we impose the available information in the object space (autocorrelation) or in the spatial-frequency space (power spectrum).