PMID- 35684820 OWN - NLM STAT- MEDLINE DCOM- 20220613 LR - 20220716 IS - 1424-8220 (Electronic) IS - 1424-8220 (Linking) VI - 22 IP - 11 DP - 2022 May 31 TI - Identity Recognition in Sanitary Facilities Using Invisible Electrocardiography. LID - 10.3390/s22114201 [doi] LID - 4201 AB - This article proposes a new method of identity recognition in sanitary facilities based on electrocardiography (ECG) signals. Our team previously proposed a novel approach of invisible ECG at the thighs using polymeric electrodes, leading to the creation of a proof-of-concept system integrated into a toilet seat. In this work, a biometrics pipeline was devised, which tested four different classifiers, varying the population from 2 to 17 subjects and simulating a residential environment. However, for this approach to be industrially viable, further optimization is required, particularly regarding electrode materials that are compatible with industrial processes. As such, we also explore the use of a conductive silicone material as electrodes, aiming at the industrial-scale production of a toilet seat capable of recording ECG data, without the need for body-worn devices. A desirable aspect when using such a system is matching the recorded data with the monitored user, ideally using a minimal sensor set, further reinforcing the relevance of user identification through ECG signals collected at the thighs. Our approach was evaluated against a reference device for a population of 17 healthy and pathological individuals, covering a wide age range (24-70 years). With the silicone composite, we were able to acquire signals in 100% of the sessions, with a mean heart rate deviation between a reference system and our experimental device of 2.82 +/- 1.99 beats per minute (BPM). In terms of ECG waveform morphology, the best cases showed a Pearson correlation coefficient of 0.91 +/- 0.06. For biometric detection, the best classifier was the Binary Convolutional Neural Network (BCNN), with an accuracy of 100% for a population of up to four individuals. FAU - Silva, Aline Santos AU - Silva AS AUID- ORCID: 0000-0001-7588-1349 AD - FEUP-Faculdade de Engenharia da Universidade do Porto, 4200-465 Porto, Portugal. AD - IT-Instituto de Telecomunicacoes, 1049-001 Lisboa, Portugal. FAU - Correia, Miguel Velhote AU - Correia MV AUID- ORCID: 0000-0001-6065-9358 AD - FEUP-Faculdade de Engenharia da Universidade do Porto, 4200-465 Porto, Portugal. AD - INESC TEC-Institute for Systems and Computer Engineering, Technology and Science, 4200-365 Porto, Portugal. FAU - de Melo, Francisco AU - de Melo F AUID- ORCID: 0000-0003-1919-4661 AD - IT-Instituto de Telecomunicacoes, 1049-001 Lisboa, Portugal. FAU - da Silva, Hugo Placido AU - da Silva HP AUID- ORCID: 0000-0001-6764-8432 AD - IT-Instituto de Telecomunicacoes, 1049-001 Lisboa, Portugal. AD - Department of Bioengineering, Instituto Superior Tecnico, 1049-001 Lisboa, Portugal. LA - eng PT - Journal Article DEP - 20220531 PL - Switzerland TA - Sensors (Basel) JT - Sensors (Basel, Switzerland) JID - 101204366 RN - 0 (Silicones) SB - IM MH - Adult MH - Aged MH - *Electrocardiography/methods MH - Heart Rate/physiology MH - Humans MH - Identity Recognition MH - Middle Aged MH - *Signal Processing, Computer-Assisted MH - Silicones MH - Young Adult PMC - PMC9185406 OTO - NOTNLM OT - biometrics OT - electrocardiography OT - identity recognition OT - invisibles OT - off-the-person OT - pervasive sensing OT - telemedicine COIS- The authors declare no conflict of interest, although noting that H.P.d.S. is a co-founder of PLUX-Wireless Biosignals, A.S.S., the company that commercializes the BITalino device used as reference, and that the research group at IT-Instituto de Telecomunicacoes within which the work is being developed has generated a spin-off company (CardioID-Technologies, Lda.) which commercializes ECG-based biometric systems. EDAT- 2022/06/11 06:00 MHDA- 2022/06/14 06:00 PMCR- 2022/05/31 CRDT- 2022/06/10 01:26 PHST- 2022/03/21 00:00 [received] PHST- 2022/05/25 00:00 [revised] PHST- 2022/05/26 00:00 [accepted] PHST- 2022/06/10 01:26 [entrez] PHST- 2022/06/11 06:00 [pubmed] PHST- 2022/06/14 06:00 [medline] PHST- 2022/05/31 00:00 [pmc-release] AID - s22114201 [pii] AID - sensors-22-04201 [pii] AID - 10.3390/s22114201 [doi] PST - epublish SO - Sensors (Basel). 2022 May 31;22(11):4201. doi: 10.3390/s22114201.