Comparison of shift-and-add & bispectrum image reconstruction methods for astronomy in the near-infrared

It is well known that atmospheric turbulence limits the resolution available to ground based astronomical observations to 0.5-1.0 arcseconds in the infrared. The advent of speckle interferometry in the 1970’s [1] has allowed the recovery of diffraction limited Fourier modulus information of astronomical objects of interest to be attempted routinely. A number of methods have since been proposed to obtain diffraction limited Fourier phase information, and thus image recovery. In the visible, where D/r o is large, it is now generally accepted that phase recovery from the average image bispectrum (or equivalently the triple correlation) appears to be the most successful [2] [3] [4].