Kalman filtering techniques for focal plane electric field estimation

TL;DR

This paper introduces a Kalman filter-based estimator for focal plane electric field estimation in coronagraphs, significantly reducing the number of exposures needed for high-contrast imaging of exoplanets.

Contribution

It presents a novel Kalman filter approach that leverages prior knowledge to improve electric field estimation efficiency and stability in high-contrast imaging systems.

Findings

Reduces the number of exposures required for electric field estimation.

Improves stability of the electric field estimate against low signal-to-noise ratios.

Demonstrates potential for adaptive, robust wavefront control algorithms.

Abstract

For a coronagraph to detect faint exoplanets, it will require focal plane wavefront control techniques to continue reaching smaller angular separations and higher contrast levels. These correction algorithms are iterative and the control methods need an estimate of the electric field at the science camera, which requires nearly all of the images taken for the correction. The best way to make such algorithms the least disruptive to science exposures is to reduce the number required to estimate the field. We demonstrate a Kalman filter estimator that uses prior knowledge to create the estimate of the electric field, dramatically reducing the number of exposures required to estimate the image plane electric field while stabilizing the suppression against poor signal-to-noise (SNR). In addition to a significant reduction in exposures, we discuss the relative merit of this algorithm to estimation schemes that do not incorporate prior state estimate history, particularly in regard to estimate error and covariance. Ultimately the filter will lead to an adaptive algorithm which can estimate physical parameters in the laboratory for robustness to variance in the optical train.