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Time-varying phase diversity turbulence compensation

Author: Eekeren, A.W.M. van · Schutte, K. · Dijk, J. · Schwering, P.B.W.
Type:article
Date:2011
Publisher: SPIE
Place: Bellingham, WA
Source:Andresen, B.F.Fulop, G.F.et al, Infrared Technology and Applications XXXVII, 25-29 April 2011, Orlando, FL
series:
Proceedings of SPIE
Identifier: 435958
doi: doi:10.1117/12.884580
Keywords: Image processing · Adaptive optics · Phase diversity · Turbulence compensation · Long range imaging · Visual identification · Defence Research · Defence, Safety and Security · Physics & Electronics · II - Intelligent Imaging ; ED - Electronic Defence · TS - Technical Sciences

Abstract

Long range object identification needs visual identification over large distances. However, atmospheric turbulence does hinder long range imaging. Therefore it is crucial to compensate the visual artifacts due to atmospheric turbulence. In this paper we propose a new method to compensate these turbulence effects, thus enabling identification at larger distances. Our method is based on applying phase diversity imaging by a wavefront modulator in free-running mode. As we have no feedback loop, we can simultaneously compensate turbulence for multiple isoplanatic angles. The wavefront modulator generates several images with known additional wave front aberrations. This extra information allows us to locally estimate the optimal wave front aberration and thus the optimal - turbulence free - image can be derived. This paper provides results on simulated data showing that this method performs well under realistic turbulence and noise conditions. Furthermore the robustness of the proposed method is shown for varying algorithmic settings. © 2011 SPIE.