Astronomical imaging nearly always involves a compact object against a relatively dark background. Often, the observer has some idea of the angular extent of the object even when detailed knowledge of the object structure is missing. I will demonstrate how this prior knowledge can be used to stablize the inverse problems involved in estimating the amplitude and phase spectrum of the unknown object. I will also demonstrate the use of a low-spatial frequency "seed" for phase estimation from the bispectrum. This latter technique is especially effective with image data compensated by adaptive optics (AO), but turns out to be effective without AO, as well.
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