Speckle imaging, photon by photon.
A speckle processing prescription is described that should yield diffraction-limited performance for large telescopes in spite of atmospheric turbulence and at light levels as low as 100 photons/sec in the picture. The prescription involves rearranging the spatial frequency components of running glimpses of the scene according to the complex information (entropy) of those components. The imaginary part (phase) of the information is rendered unambiguous by maintaining track of the phase. A 2-D photon counter furnishes the raw observations. Comparisons and ramifications of the procedure are discussed.
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