{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T13:02:15Z","timestamp":1782997335532,"version":"3.54.5"},"reference-count":79,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2020,3,30]],"date-time":"2020-03-30T00:00:00Z","timestamp":1585526400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Humanities and Social Sciences Foundation of China Ministry of Education","award":["18YJAZH065"],"award-info":[{"award-number":["18YJAZH065"]}]},{"name":"RD program of Shenzhen","award":["JCYJ20170307153032483"],"award-info":[{"award-number":["JCYJ20170307153032483"]}]},{"name":"RD program of Shenzhen","award":["JCYJ20170817161546744"],"award-info":[{"award-number":["JCYJ20170817161546744"]}]},{"name":"Shenzhen Key Research Base of Humanities and Social Sciences and the Interdisciplinary Research Project of Graduate School of Shenzhen of Tsinghua University","award":["JC2017005"],"award-info":[{"award-number":["JC2017005"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Heart rate variability (HRV) provides essential health information such as the risks of heart attacks and mental disorders. However, inconvenience related to the accurate detection of HRV limits its potential applications. The ubiquitous use of smartphones makes them an excellent choice for regular and portable health monitoring. Following this trend, smartphone photoplethysmography (PPG) has recently garnered prominence; however, the lack of robustness has prevented both researchers and practitioners from embracing this technology. This study aimed to bridge the gap in the literature by developing a novel smartphone PPG quality index (SPQI) that can filter corrupted data. A total of 226 participants joined the study, and results from 1343 samples were used to validate the proposed sinusoidal function-based model. In both the correlation coefficient and Bland\u2013Altman analyses, the agreement between HRV measurements generated by both the smartphone PPG and the reference electrocardiogram improved when data were filtered through the SPQI. Our results support not only the proposed approach but also the general value of using smartphone PPG in HRV analysis.<\/jats:p>","DOI":"10.3390\/s20071923","type":"journal-article","created":{"date-parts":[[2020,4,1]],"date-time":"2020-04-01T03:44:13Z","timestamp":1585712653000},"page":"1923","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Enhancing the Robustness of Smartphone Photoplethysmography: A Signal Quality Index Approach"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8171-9356","authenticated-orcid":false,"given":"Ivan","family":"Liu","sequence":"first","affiliation":[{"name":"Data Science and Information Technology Research Center, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiguang","family":"Ni","sequence":"additional","affiliation":[{"name":"Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kaiping","family":"Peng","sequence":"additional","affiliation":[{"name":"Data Science and Information Technology Research Center, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China"},{"name":"Department of Psychology, Tsinghua University, Beijing 100084, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1040","DOI":"10.3389\/fpsyg.2014.01040","article-title":"A healthy heart is not a metronome: An integrative review of the heart\u2019s anatomy and heart rate variability","volume":"5","author":"Shaffer","year":"2014","journal-title":"Front. 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