{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T18:09:10Z","timestamp":1782497350441,"version":"3.54.5"},"reference-count":27,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,11]],"date-time":"2023-07-11T00:00:00Z","timestamp":1689033600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Unobtrusive Monitoring of Sleep Apnea, UMOSA","award":["17117"],"award-info":[{"award-number":["17117"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Instantaneous heart rate (IHR) has been investigated for sleep applications, such as sleep apnea detection and sleep staging. To ensure the comfort of the patient during sleep, it is desirable for IHR to be measured in a contact-free fashion. In this work, we use speckle vibrometry (SV) to perform on-skin and on-textile IHR monitoring in a sleep setting. Minute motions on the laser-illuminated surface can be captured by a defocused camera, enabling the detection of cardiac motions even on textiles. We investigate supine, lateral, and prone sleeping positions. Based on Bland\u2013Altman analysis between SV cardiac measurements and electrocardiogram (ECG), with respect to each position, we achieve the best limits of agreement with ECG values of [\u22128.65, 7.79] bpm, [\u22129.79, 9.25] bpm, and [\u221210.81, 10.23] bpm, respectively. The results indicate the potential of using speckle vibrometry as a contact-free monitoring method for instantaneous heart rate in a setting where the participant is allowed to rest in a spontaneous position while covered by textile layers.<\/jats:p>","DOI":"10.3390\/s23146312","type":"journal-article","created":{"date-parts":[[2023,7,12]],"date-time":"2023-07-12T01:05:01Z","timestamp":1689123901000},"page":"6312","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Speckle Vibrometry for Instantaneous Heart Rate Monitoring"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2806-5255","authenticated-orcid":false,"given":"Shuhao","family":"Que","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5486-9663","authenticated-orcid":false,"given":"Fokke","family":"van Meulen","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands"},{"name":"Kempenhaeghe, 5590AB Heeze, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1381-2740","authenticated-orcid":false,"given":"Willem","family":"Verkruijsse","sequence":"additional","affiliation":[{"name":"Philips, 5656AE Eindhoven, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5422-0143","authenticated-orcid":false,"given":"Mark","family":"van Gastel","sequence":"additional","affiliation":[{"name":"Philips, 5656AE Eindhoven, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6445-9836","authenticated-orcid":false,"given":"Sebastiaan","family":"Overeem","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands"},{"name":"Kempenhaeghe, 5590AB Heeze, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sveta","family":"Zinger","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2518-6847","authenticated-orcid":false,"given":"Sander","family":"Stuijk","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/0013-4694(76)90161-9","article-title":"Detection of cyclic sleep phenomena using instantaneous heart rate","volume":"40","author":"Lisenby","year":"1976","journal-title":"Electroencephalogr. 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