DeepAI AI Chat
Log In Sign Up

Imaging from STIX visibility amplitudes

08/10/2021
by   Paolo Massa, et al.
berkeley college
Università di Genova
FHNW
0

Aims: To provide the first demonstration of STIX Fourier-transform X-ray imaging using semi-calibrated (amplitude-only) visibility data acquired during the Solar Orbiter's cruise phase. Methods: We use a parametric imaging approach by which STIX visibility amplitudes are fitted by means of two non-linear optimization methods: a fast meta-heuristic technique inspired by social behavior, and a Bayesian Monte Carlo sampling method, which, although slower, provides better quantification of uncertainties. Results: When applied to a set of solar flare visibility amplitudes recorded by STIX on November 18, 2020 the two parametric methods provide very coherent results. The analysis also demonstrates the ability of STIX to reconstruct high time resolution information and, from a spectral viewpoint, shows the reliability of a double-source scenario consistent with a thermal versus nonthermal interpretation. Conclusions: In this preliminary analysis of STIX imaging based only on visibility amplitudes, we formulate the imaging problem as a non-linear parametric issue we addressed by means of two high-performance optimization techniques that both showed the ability to sample the parametric space in an effective fashion, thus avoiding local minima.

READ FULL TEXT

page 4

page 8

12/27/2020

Visibility Interpolation in Solar Hard X-ray Imaging: Application to RHESSI and STIX

Space telescopes for solar hard X-ray imaging provide observations made ...
12/20/2018

Compressed sensing and Sequential Monte Carlo for solar hard X-ray imaging

We describe two inversion methods for the reconstruction of hard X-ray s...
07/30/2018

Sparse Bayesian Imaging of Solar Flares

We consider imaging of solar flares from NASA RHESSI data as a parametri...
04/29/2022

Forward-fitting STIX visibilities

Aima. To determine to what extent the problem of forward fitting visibil...
08/13/2017

Solar hard X-ray imaging by means of Compressed Sensing and Finite Isotropic Wavelet Transform

This paper shows that compressed sensing realized by means of regularize...
04/24/2020

Bayesian Non-parametric Bragg-edge Fitting for Neutron Transmission Strain Imaging

Energy resolved neutron transmission techniques can provide high-resolut...
05/08/2020

Fast Automatic Visibility Optimization for Thermal Synthetic Aperture Visualization

In this article, we describe and validate the first fully automatic para...