Speckle processing gives diffraction-limited true images from severely aberrated instruments.
Speckle images of spatially incoherent objects viewed under severe seeing conditions are formed in the optical laboratory (organized for simulations of stellar speckle interferometry). The brightest pixel in each speckle image is shifted to the center of image space, and the translated image is added to all other speckle images that have been similarly processed. A recognizable diffraction-limited version of the true image of the object results, even when the imaging instrument is defocused such that, under perfect seeing conditions, the Airy disk is spread over an area comparable with that covered by a typical speckle image.
Cady
F M
FM
Bates
R H
RH