Abstract

Since the average brightness distribution of astronomical objects and the mutual intensity (complex coherence function) of the observed field are related by a Fourier transform, it is possible to synthesize images from far-field correlation measurements. Owing to the fact that detected intensities (rather than complex fields) are correlated at the receiver, intensity interferometry is an approach to measuring such correlations, which is largely insensitive to the effects of the earth’s atmosphere. We investigate the effect that atmosphere-induced fluctuations in the detected field amplitude (i.e., atmospheric scintillation) have on one’s ability to recover imagery using intensity interferometer data. To model the effects of the atmosphere on two-point intensity correlation measurements, we have adopted the theory of Beran and Whitman¹ which provides expressions for the scintillation covariance function (in the case of isoplanaticity) and a first-order isoplanatic correction. We report on our attempt to verify these relations in a laboratory setting using Gaussian phase screens of known statistics² and an image recovery methodology known as imaging correlography.³ We also investigate the performance of postdetection processing schemes applied to compensate for the effects of scintillation in the digitally recovered imagery.

© 1988 Optical Society of America