Mean squared error performance of speckle-imaging using the bispectrum in horizontal imaging applications

Abstract

The problem of horizontal imaging through the atmospheric boundary layer is common in defense, surveillance and remote sensing applications. Like all earth-bound imaging systems the resolving capability of an imaging system is limited by atmospheric turbulence. Using speckle imaging techniques it is often possible to overcome these effects and recover images with resolution approaching the diffraction-limit. We examine the performance of a bispectrum-based speckle imaging technique when applied to imaging scenarios near the ground. Computer simulations were used to generate three sets of 70, turbulence degraded images with varied turbulence strength. Early results indicate the bispectrum to be a robust estimator for images corrupted by the anisoplanatic turbulence encountered when imaging horizontally. Bispectrum reconstructed image frames show an improvement of nearly 60% in Mean Squared Error (MSE) on average over the examined turbulence strengths. The improvement in MSE was found to increase as additional input frames used for image reconstruction though using a few as 10 input frames provided a 50% improvement in MSE on average over turbulence strengths.