STIX is a X-ray imaging spectroscopy device to be mounted as part of the Solar Orbiter cluster. Its goal is to provide images and spectra of solar flaring regions. The device provides 30 measurements of the incoming photon flux which can be interpreted as spatial Fourier samples. In this paper we present a method for reconstructing the...
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2017 (v1)PublicationUploaded on: March 27, 2023
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2008 (v1)Publication
The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) uses rotational modulation synthesis for imaging hard X-ray flares with unprecedented spatial and spectral resolution. As the spacecraft rotates, imaging information is encoded as rapid time-variations of the detected flux. We introduce a novel method for imaging spectroscopy...
Uploaded on: February 14, 2024 -
2019 (v1)Publication
We describe two inversion methods for the reconstruction of hard Xray solar images. The methods are tested against experimental visibilities recorded by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and synthetic visibilities based on the design of the Spectrometer/Telescope for Imaging X-rays (STIX).
Uploaded on: April 14, 2023 -
2021 (v1)Publication
We investigate an interpolation/extrapolation method that, given scattered observations of the Fourier transform, approximates its inverse. The interpolation algorithm takes advantage of modeling the available data via a shape-driven interpolation based on variably scaled Kernels (VSKs), whose implementation is here tailored for inverse...
Uploaded on: April 14, 2023 -
2022 (v1)Publication
The idea for this text emerged over several years as the authors participated in research projects related to analysis of data from NASA's RHESSI Small Explorer mission. The data produced over the operational lifetime of this mission inspired many investigations related to a specific science question: the when, where, and how of electron...
Uploaded on: February 4, 2024 -
2019 (v1)Publication
The Spectrometer/Telescope for Imaging X-rays (STIX) will study solar flares across the hard X-ray window provided by the Solar Orbiter cluster. Similarly to the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), STIX is a visibility-based imaging instrument that will require Fourier-based image reconstruction methods. However, in...
Uploaded on: April 14, 2023 -
2020 (v1)Publication
In the framework of the Hough transform technique to detect curves in images, we provide a bound for the number of Hough transforms to be considered for a successful optimization of the accumulator function in the recognition algorithm. Such a bound is consequence of geometrical arguments. We also show the robustness of the results when applied...
Uploaded on: April 14, 2023 -
2015 (v1)Publication
This paper describes a classification method for automatic fault detection in nuclear power plant (NPP) data. The method takes as input time series associated to specific parameters and realizes signal classification by using a clustering algorithm based on possibilistic C-means (PCM). This approach is applied to time series recorded in a...
Uploaded on: February 11, 2024 -
2021 (v1)Publication
Space telescopes for solar hard X-ray imaging provide observations made of sampled Fourier components of the incoming photon flux. The aim of this study is to design an image reconstruction method relying on enhanced visibility interpolation in the Fourier domain. The interpolation-based method is applied to synthetic visibilities generated by...
Uploaded on: April 14, 2023 -
2018 (v1)Publication
'Flare Likelihood and Region Eruption Forecasting (FLARECAST)' is a Horizon 2020 project, which realized a technological platform for machine learning algorithms, with the objective of providing the space weather community with a prediction service for solar flares. This paper describes the FLARECAST service and shows how the methods...
Uploaded on: October 11, 2023 -
2017 (v1)Publication
Synaptic activity in the nervous system consumes glucose. Therefore Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) may in principle provide iconographic representations of glucose utilization impairment in neurodegenerative diseases and, specifically, in Amyotrophic Lateral Sclerosis (ALS). In a previous paper, we developed a...
Uploaded on: April 14, 2023 -
2019 (v1)Publication
We describe here the application of a machine learning method for flare forecasting using vectors of properties extracted from images provided by the Helioseismic and Magnetic Imager in the Solar Dynamics Observatory (SDO/HMI). We also discuss how the method can be used to quantitatively assess the impact of such properties on the prediction process.
Uploaded on: April 14, 2023 -
2019 (v1)Publication
Image saturation has been an issue for several instruments in solar astronomy, mainly at EUV wavelengths. However, with the launch of the Atmospheric Imaging Assembly (AIA) as part of the payload of the Solar Dynamic Observatory image saturation has become a big data issue, involving around 105 frames of the impressive data set the telescope...
Uploaded on: April 14, 2023