Super-resolution from unregistered aliased astronomical images

Abstract

Images captured from astronomical telescopes always have aliasing artifacts due to atmospheric turbulence, which typically conveys additional high-frequency content containing extra details of the astronomical scene. Super-resolution (SR) reconstruction can exploit the information existing in the aliasing to create a higher-resolution astronomical image, where the precise registration of input observations is generally regarded as a necessary premise. We consider SR reconstruction as a multichannel sampling scheme with uncertain deviations mathematically and present a frequency domain technique to achieve accurate alignment of aliased astronomical images by utilizing their low-frequency and aliasing-free part of the spectrum. Moreover, a planar motion model including three parameters is allowed to describe the relative uncontrolled motions between the acquisition system and the astronomical scene. Finally, a sharp high-resolution astronomical image can be reconstructed by utilizing the adaptive normalized convolution algorithm. The technique proposed is tested in simulations and practical experiments and shows very excellent SR reconstruction capabilities in the case of aliased astronomical images.