Bispectral analysis at low light levels and astronomical speckle masking

Abstract

The bispectrum is the Fourier transform of the triple correlation, sometimes also referred to as the triple-product integral. The influence of photon noise on the bispectrum of an image-intensity distribution is discussed. As an example, the astronomical speckle-masking method is considered. Speckle masking is a method to overcome image degradation that is due to the turbulent atmosphere. It is shown theoretically that bispectral analysis in speckle masking should yield true, diffraction-limited images in all those cases in which the speckle-interferometry process has been successful in reconstructing the object autocorrelation.