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Proceedings Paper

GPU-based simulation of optical propagation through turbulence for active and passive imaging
Author(s): Goulven Monnier; François-Régis Duval; Solène Amram
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Paper Abstract

The usual numerical approach for accurate, spatially resolved simulation of optical propagation through atmospheric turbulence involves Fresnel diffraction through a series of phase screens. When used to reproduce instantaneous laser beam intensity distribution on a target, this numerical scheme may get quite expensive in terms of CPU and memory resources, due to the many constraints to be fulfilled to ensure the validity of the resulting quantities. In particular, computational requirements grow rapidly with higher-divergence beam, longer propagation distance, stronger turbulence and larger turbulence outer scale. Our team recently developed IMOTEP, a software which demonstrates the benefits of using the computational power of the Graphics Processing Units (GPU) for both accelerating such simulations and increasing the range of accessible simulated conditions. Simulating explicitly the instantaneous effects of turbulence on the backscattered optical wave is even more challenging when the isoplanatic or totally anisoplanatic approximations are not applicable. Two methods accounting for anisoplanatic effects have been implemented in IMOTEP. The first one, dedicated to narrow beams and non-imaging applications, involves exact propagation of spherical waves for an array of isoplanatic sources in the laser spot. The second one, designed for active or passive imaging applications, involves precomputation of the DSP of parameters describing the instantaneous PSF. PSF anisoplanatic statistics are "numerically measured" from numerous simulated realizations. Once the DSP are computed and stored for given conditions (with no intrinsic limitation on turbulence strength), which typically takes 5 to 30 minutes on a recent GPU, output blurred and distorted images are easily and quickly generated. The paper gives an overview of the software with its physical and numerical backgrounds. The approach developed for generating anisoplanatic instantaneous images is emphasized.

Paper Details

Date Published: 1 November 2012
PDF: 10 pages
Proc. SPIE 8535, Optics in Atmospheric Propagation and Adaptive Systems XV, 85350D (1 November 2012); doi: 10.1117/12.981528
Show Author Affiliations
Goulven Monnier, ALYOTECH Technologies (France)
François-Régis Duval, ALYOTECH Technologies (France)
Solène Amram, ALYOTECH Technologies (France)

Published in SPIE Proceedings Vol. 8535:
Optics in Atmospheric Propagation and Adaptive Systems XV
Karin Stein; John Gonglewski, Editor(s)

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