{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T13:45:35Z","timestamp":1775742335492,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2023,5,9]],"date-time":"2023-05-09T00:00:00Z","timestamp":1683590400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Applied Sciences"],"abstract":"<jats:p>Solar activity has been subject to increasingly more research in the last decades. Its influence on life on Earth is now better understood. Solar winds impact the earth\u2019s magnetic field and atmosphere. They can disrupt satellite communication and navigation tools and even electrical power grids and several other infrastructure crucial for our technology-based society. Coronal mass ejections (CMEs), solar energetic particles, and flares are the main causes of problems that affect the systems mentioned. It is possible to predict some of those by monitoring the sun and analyzing the images obtained in different spectra, thus identifying solar phenomena related to its activity, such as filaments, pores, and sunspots. Several studies have already been carried out on the subject of automation of the mentioned analysis, most of which use neural networks and other machine learning approaches. In this work, we develop a method for sunspot detection based on the YOLOv5 network, applying it to a dataset of images from the Geophysical and Astronomical Observatory of the University of Coimbra (OGAUC), which has one of the oldest and more complete datasets of sun images in the world. Our method reaches mAP@.5 over 90% with YOLOv5s, which is higher than other methods previously applied for the same dataset. This shows that CNN models can be used in spectroheliographs for detecting and tracking sunspots.<\/jats:p>","DOI":"10.3390\/app13105833","type":"journal-article","created":{"date-parts":[[2023,5,10]],"date-time":"2023-05-10T03:32:27Z","timestamp":1683689547000},"page":"5833","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Sunspot Detection Using YOLOv5 in Spectroheliograph H-Alpha Images"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-5597-7791","authenticated-orcid":false,"given":"Jos\u00e9","family":"Santos","sequence":"first","affiliation":[{"name":"Coimbra Institute of Engineering, Rua Pedro Nunes-Quinta da Nora, Polytechnic Institute of Coimbra, 3030-199 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6830-476X","authenticated-orcid":false,"given":"Nuno","family":"Peixinho","sequence":"additional","affiliation":[{"name":"Instituto de Astrof\u00edsica e Ci\u00eancias do Espa\u00e7o, Universidade de Coimbra, 3040-004 Coimbra, Portugal"},{"name":"Departamento de F\u00edsica, Faculdade de Ci\u00eancias e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6106-8285","authenticated-orcid":false,"given":"Teresa","family":"Barata","sequence":"additional","affiliation":[{"name":"Instituto de Astrof\u00edsica e Ci\u00eancias do Espa\u00e7o, Universidade de Coimbra, 3040-004 Coimbra, Portugal"},{"name":"Departamento de Ci\u00eancias da Terra, Faculdade de Ci\u00eancias e Tecnologia, Universidade de Coimbra, 3030-790 Coimbra, Portugal"}]},{"given":"Carlos","family":"Pereira","sequence":"additional","affiliation":[{"name":"Coimbra Institute of Engineering, Rua Pedro Nunes-Quinta da Nora, Polytechnic Institute of Coimbra, 3030-199 Coimbra, Portugal"},{"name":"Centre for Informatics and Systems of the University of Coimbra, 3030-290 Coimbra, Portugal"}]},{"given":"A. Paulo","family":"Coimbra","sequence":"additional","affiliation":[{"name":"Institute of Systems and Robotics, University of Coimbra, 3004-531 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3240-7564","authenticated-orcid":false,"given":"Manuel M.","family":"Cris\u00f3stomo","sequence":"additional","affiliation":[{"name":"Institute of Systems and Robotics, University of Coimbra, 3004-531 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4313-7966","authenticated-orcid":false,"given":"Mateus","family":"Mendes","sequence":"additional","affiliation":[{"name":"Coimbra Institute of Engineering, Rua Pedro Nunes-Quinta da Nora, Polytechnic Institute of Coimbra, 3030-199 Coimbra, Portugal"},{"name":"Institute of Systems and Robotics, University of Coimbra, 3004-531 Coimbra, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2","DOI":"10.12942\/lrsp-2006-2","article-title":"Space weather: The solar perspective","volume":"3","author":"Schwenn","year":"2006","journal-title":"Living Rev. 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