{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,20]],"date-time":"2026-03-20T15:54:15Z","timestamp":1774022055964,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2022,10,15]],"date-time":"2022-10-15T00:00:00Z","timestamp":1665792000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Polytechnic Institute of Coimbra","award":["12598\/2020"],"award-info":[{"award-number":["12598\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>Prior to the implementation of digitisation processes, the handwritten signature in an attendance sheet was the preferred way to prove the presence of each student in a classroom. The method is still preferred, for example, for short courses or places where other methods are not implemented. However, human verification of handwritten signatures is a tedious process. The present work describes two methods for classifying signatures in an attendance sheet as valid or not. One method based on Optical Mark Recognition is general but determines only the presence or absence of a signature. The other method uses a multiclass convolutional neural network inspired by the AlexNet architecture and, after training with a few pieces of genuine training data, shows over 85% of precision and recall recognizing the author of the signatures. The use of data augmentation and a larger number of genuine signatures ensures higher accuracy in validating the signatures.<\/jats:p>","DOI":"10.3390\/en15207611","type":"journal-article","created":{"date-parts":[[2022,10,17]],"date-time":"2022-10-17T00:04:55Z","timestamp":1665965095000},"page":"7611","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Offline Handwritten Signature Verification Using Deep Neural Networks"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6216-7162","authenticated-orcid":false,"given":"Jos\u00e9","family":"Lopes","sequence":"first","affiliation":[{"name":"Polytechnic of Coimbra, Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8583-6904","authenticated-orcid":false,"given":"Bernardo","family":"Baptista","sequence":"additional","affiliation":[{"name":"Polytechnic of Coimbra, Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8237-3086","authenticated-orcid":false,"given":"Nuno","family":"Lavado","sequence":"additional","affiliation":[{"name":"Polytechnic of Coimbra, Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4313-7966","authenticated-orcid":false,"given":"Mateus","family":"Mendes","sequence":"additional","affiliation":[{"name":"Polytechnic of Coimbra, Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra, Portugal"},{"name":"Instituto de Sistemas e Rob\u00f3tica, University of Coimbra, 3030-194 Coimbra, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,15]]},"reference":[{"key":"ref_1","first-page":"63","article-title":"Tackling the digitalization challenge: How to benefit from digitalization in practice","volume":"5","author":"Parviainen","year":"2017","journal-title":"Int. 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