Document Type

Conference Paper

Publication Date

5-2017

Publication Source

Proceedings of SPIE 10204, Long-Range Imaging II

Abstract

We describe a numerical wave propagation method for simulating long range imaging of an extended scene under anisoplanatic conditions. Our approach computes an array of point spread functions (PSFs) for a 2D grid on the object plane. The PSFs are then used in a spatially varying weighted sum operation, with an ideal image, to produce a simulated image with realistic optical turbulence degradation. To validate the simulation we compare simulated outputs with the theoretical anisoplanatic tilt correlation and differential tilt variance. This is in addition to comparing the long- and short-exposure PSFs, and isoplanatic angle. Our validation analysis shows an excellent match between the simulation statistics and the theoretical predictions. The simulation tool is also used here to quantitatively evaluate a recently proposed block- matching and Wiener filtering (BMWF) method for turbulence mitigation. In this method block-matching registration algorithm is used to provide geometric correction for each of the individual input frames. The registered frames are then averaged and processed with a Wiener filter for restoration. A novel aspect of the proposed BMWF method is that the PSF model used for restoration takes into account the level of geometric correction achieved during image registration. This way, the Wiener filter is able fully exploit the reduced blurring achieved by registration. The BMWF method is relatively simple computationally, and yet, has excellent performance in comparison to state-of-the-art benchmark methods.

Inclusive pages

102040B-1-102040B-20

Document Version

Published Version

Comments

Document is provided in compliance with the publisher's policy on self-archiving. Permission documentation is on file. Paper was presented at SPIE Defense + Security, Anaheim, California, United States, April 9, 2017.

This work has been supported in part by funding from L-3 Communications Cincinnati Electronics and under AFRL Award No. FA8650-10-2-7028 and FA9550-14-1-0244.

Publisher

SPIE

Peer Reviewed

yes

Keywords

atmospheric turbulence, anisoplanatic, simulation, optical wave propagation, turbulence mitigation