The SWAP Filter: A Simple Azimuthally Varying Radial Filter for Wide-Field EUV Solar Images

Daniel B. Seaton*, David Berghmans, Shaun Bloomfield, Anik De Groof, Elke D’Huys, Bogdan Nicula, Laurel A. Rachmeler, Matthew J. West

*Corresponding author for this work

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We present the SWAP Filter: an azimuthally varying, radial normalizing filter specifically developed for EUV images of the solar corona, named for the Sun Watcher with Active Pixels and Image Processing (SWAP) instrument on the Project for On-Board Autonomy 2 (PROBA2) spacecraft. We discuss the origins of our technique, its implementation and key user-configurable parameters, and highlight its effects on data via a series of examples. We discuss the filter’s strengths in a data environment in which wide field-of-view observations that specifically target the low signal-to-noise middle corona are newly available and expected to grow in the coming years.
Original languageEnglish
Article number92
Number of pages17
JournalSolar Physics
Issue number7
Publication statusPublished - 18 Jul 2023

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