title: Overcoming turbulence-induced space-variant blur by using phase-diverse speckle.
abstract: Space-variant blur occurs when imaging through volume turbulence over sufficiently large fields of view. Space-variant effects are particularly severe in horizontal-path imaging, slant-path (air-to-ground or ground-to-air) geometries, and ground-based imaging of low-elevation satellites or astronomical objects. In these geometries, the isoplanatic angle can be comparable to or even smaller than the diffraction-limited resolution angle. We report on a postdetection correction method that seeks to correct for the effects of space-variant aberrations, with the goal of reconstructing near-diffraction-limited imagery. Our approach has been to generalize the method of phase-diverse speckle (PDS) by using a physically motivated distributed-phase-screen model. Simulation results are presented that demonstrate the reconstruction of near-diffraction-limited imagery under both matched and mismatched model assumptions. In addition, we present evidence that PDS could be used as a beaconless wavefront sensor in a multiconjugate adaptive optics system when imaging extended scenes.
authors.affiliation: General Dynamics Advanced Information Systems, Ypsilanti, MI 48197, USA. brian.thelen@mtu.edu
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Thelen
authors.forename: Richard G
authors.initials: RG
authors.lastname: Paxman
authors.forename: David A
authors.initials: DA
authors.lastname: Carrara
authors.forename: John H
authors.initials: JH
authors.lastname: Seldin