COMPARISON OF FOURIER PHASE SPECTRUM ESTIMATION USING DECONVOLUTION FROM WAVE-FRONT SENSING AND BISPECTRUM RECONSTRUCTION

Atmospheric turbulence limits the resolution of astronomical optical i maging systems, Speckle imaging and deconvolution from wavefront sensi ng (DWFS) are two post-detection image processing methods for overcomi ng some turbulence effects which do not require adaptive optics. Both speckle imaging and DWFS create estimates of the object irradiance dis tribution by first estimating the Fourier transform, or spectrum of th e object, Previous work has established the signal-to-noise ratio perf ormance for some of the estimators used in both speckle imaging and DW FS. However, the comparative quality of the object spectrum phase esti mation provided by these two techniques has not been studied in detail , In this paper we present the results of a simulation study of the co mparative Fourier phase estimation errors for speckle imaging using th e bispectrum technique, and DWFS, It is shown that even for good wavef ront sampling and bright objects DWFS provides Fourier phase spectrum estimation of lower quality than the phase spectrum estimate provided by the bispectrum technique, When the beacon is not bright enough to p rovide a good signal-to-noise ratio in the wavefront sensor the bispec trum technique provides much better Fourier phase spectrum estimation than DWFS.