Speckle statistics in adaptive optics images at visible wavelengths

TL;DR

This paper analyzes the statistical properties and dynamics of residual speckles in high-cadence adaptive optics images at visible wavelengths, aiding in the development of speckle noise mitigation techniques.

Contribution

It provides a detailed characterization of AO residual speckles using high-temporal-resolution data, enhancing simulation realism and informing noise reduction methods.

Findings

Speckle patterns are statistically characterized.

Speckle dynamics are analyzed using information theory.

Results improve speckle noise mitigation strategies.

Abstract

Residual speckles in adaptive optics (AO) images represent a well-known limitation on the achievement of the contrast needed for faint source detection. Speckles in AO imagery can be the result of either residual atmospheric aberrations, not corrected by the AO, or slowly evolving aberrations induced by the optical system. We take advantage of the high temporal cadence (1 ms) of the data acquired by the System for Coronagraphy with High-order Adaptive Optics from R to K bands-VIS forerunner experiment at the Large Binocular Telescope to characterize the AO residual speckles at visible wavelengths. An accurate knowledge of the speckle pattern and its dynamics is of paramount importance for the application of methods aimed at their mitigation. By means of both an automatic identification software and information theory, we study the main statistical properties of AO residuals and their dynamics. We therefore provide a speckle characterization that can be incorporated into numerical simulations to increase their realism and to optimize the performances of both real-time and postprocessing techniques aimed at the reduction of the speckle noise.