Parallel faceted imaging in radio interferometry via proximal splitting (Faceted HyperSARA): II. Code and real data proof of concept

Pierre-Antoine Thouvenin, Arwa Dabbech, Ming Jiang, Abdullah Abdulaziz, Jean-Philippe Thiran, Adrian Jackson, Yves Wiaux

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
38 Downloads (Pure)

Abstract

In a companion paper, a faceted wideband imaging technique for radio interferometry, dubbed Faceted HyperSARA, has been introduced and validated on synthetic data. Building on the recent HyperSARA approach, Faceted HyperSARA leverages the splitting functionality inherent to the underlying primal-dual forward-backward algorithm to decompose the image reconstruction over multiple spatio-spectral facets. The approach allows complex regularization to be injected into the imaging process while providing additional parallelization flexibility compared to HyperSARA. This paper introduces new algorithm functionalities to address real data sets, implemented as part of a fully fledged MATLAB imaging library made available on GITHUB. A large-scale proof of concept is proposed to validate Faceted HyperSARA in a new data and parameter scale regime, compared to the state of the art. The reconstruction of a 15 GB wideband image of Cyg A from 7.4 GB of Very Large Array data is considered, utilizing 1440 CPU cores on a high-performance computing system for about 9 h. The conducted experiments illustrate the reconstruction performance of the proposed approach on real data, exploiting new functionalities to leverage known direction-dependent effects, for an accurate model of the measurement operator, and an effective noise level accounting for imperfect calibration. They also demonstrate that, when combined with a further dimensionality reduction functionality, Faceted HyperSARA enables the recovery of a 3.6 GB image of Cyg A from the same data using only 91 CPU cores for 39 h. In this setting, the proposed approach is shown to provide a superior reconstruction quality compared to the state-of-the-art wideband CLEAN-based algorithm of the WSCLEAN software.

Original languageEnglish
Pages (from-to)20–34
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume521
Issue number1
Early online date11 Nov 2022
DOIs
Publication statusPublished - May 2023

Keywords

  • image processing-techniques
  • interferometric
  • techniques

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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