Kernel Phase and Kernel Amplitude in Fizeau Imaging

TL;DR

This paper discusses kernel phase and introduces kernel amplitude methods to improve high angular resolution imaging by self-calibrating amplitude errors, extending speckle imaging capabilities.

Contribution

It proposes a novel generalization of closure amplitude to kernel amplitudes, enhancing calibration in optical imaging for symmetric targets.

Findings

Kernel amplitude extends kernel phase techniques to amplitude calibration.

Self-calibration of throughput and scintillation errors improves imaging quality.

Enables high angular resolution imaging of symmetric targets.

Abstract

Kernel phase interferometry is an approach to high angular resolution imaging which enhances the performance of speckle imaging with adaptive optics. Kernel phases are self-calibrating observables that generalize the idea of closure phases from non-redundant arrays to telescopes with arbitrarily shaped pupils, by considering a matrix-based approximation to the diffraction problem. In this paper I discuss the recent history of kernel phase, in particular in the matrix-based study of sparse arrays, and propose an analogous generalization of the closure amplitude to kernel amplitudes. This new approach can self-calibrate throughput and scintillation errors in optical imaging, which extends the power of kernel phase-like methods to symmetric targets where amplitude and not phase calibration can be a significant limitation, and will enable further developments in high angular resolution astronomy.