{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T07:47:09Z","timestamp":1773733629677,"version":"3.50.1"},"reference-count":15,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2017,10,19]],"date-time":"2017-10-19T00:00:00Z","timestamp":1508371200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002560","name":"Soonchunhyang University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100002560","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100016400","name":"NRF","doi-asserted-by":"publisher","award":["NRF-2015M3A9D7067219"],"award-info":[{"award-number":["NRF-2015M3A9D7067219"]}],"id":[{"id":"10.13039\/100016400","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Smartphones and tablets are widely used in medical fields, which can improve healthcare and reduce healthcare costs. Many medical applications for smartphones and tablets have already been developed and widely used by both health professionals and patients. Specifically, video recordings of fingertips made using a smartphone camera contain a pulsatile component caused by the cardiac pulse equivalent to that present in a photoplethysmographic signal. By performing peak detection on the pulsatile signal, it is possible to estimate a continuous heart rate and a respiratory rate. To estimate the heart rate and respiratory rate accurately, which pixel regions of the color bands give the most optimal signal quality should be investigated. In this paper, we investigate signal quality to determine the best signal quality by the largest amplitude values for three different smartphones under different conditions. We conducted several experiments to obtain reliable PPG signals and compared the PPG signal strength in the three color bands when the flashlight was both on and off. We also evaluated the intensity changes of PPG signals obtained from the smartphones with motion artifacts and fingertip pressure force. Furthermore, we have compared the PSNR of PPG signals of the full-size images with that of the region of interests (ROIs).<\/jats:p>","DOI":"10.3390\/s17102385","type":"journal-article","created":{"date-parts":[[2017,10,19]],"date-time":"2017-10-19T11:07:29Z","timestamp":1508411249000},"page":"2385","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Photoplethysmography Signal Analysis for Optimal Region-of-Interest Determination in Video Imaging on a Built-In Smartphone under Different Conditions"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3318-9394","authenticated-orcid":false,"given":"Yunyoung","family":"Nam","sequence":"first","affiliation":[{"name":"Department of Computer Science and Engineering, Soonchunhyang University, Asan 31538, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yun-Cheol","family":"Nam","sequence":"additional","affiliation":[{"name":"Department of Architecture, Joongbu University, Goyang 10279, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,10,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Rahmati, A., and Zhong, L. 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Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1007\/s10439-013-0944-x","article-title":"Respiratory Rate Estimation from the Built-in Cameras of Smartphones and Tablets","volume":"42","author":"Nam","year":"2014","journal-title":"Ann. Biomed. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"9773","DOI":"10.3390\/s150509773","article-title":"Tidal Volume Estimation Using the Blanket Fractal Dimension of the Tracheal Sounds Acquired by Smartphone","volume":"15","author":"Reljin","year":"2015","journal-title":"Sensors"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Nam, Y., Kong, Y., Reyes, B., Reljin, N., and Chon, K.H. (2016). Monitoring of Heart and Respiratory Rates Using Dual Cameras on a Smartphone. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0151013"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Lamonaca, F., Kurylyak, Y., Grimaldi, D., and Spagnuolo, V. (2012, January 18\u201319). Reliable Pulse Rate Evaluation by Smartphone. Proceedings of the 2012 IEEE International Symposium on Medical Measurements and Applications (MeMeA), Budapest, Hungary.","DOI":"10.1109\/MeMeA.2012.6226672"},{"key":"ref_10","unstructured":"Kurylyak, Y., Lamonaca, F., and Grimaldi, D. (2012). Smartphone Based Photoplethysmogram Measurement. Digital Image and Signal Processing for Measurement Systems, River Publishers."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Po, L.M., Xu, X., Feng, L., Li, Y., Cheung, K.W., and Cheung, C.H. (2015, January 24\u201327). Frame Adaptive ROI for Photoplethysmography Signal Extraction from Fingertip Video Captured by Smartphone. Proceedings of the 2015 IEEE International Symposium on Circuits and Systems (ISCAS) IEEE, Lisbon, Portugal.","DOI":"10.1109\/ISCAS.2015.7168963"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1272","DOI":"10.3758\/s13428-012-0312-z","article-title":"iPhysioMeter: A New Approach for Measuring Heart Rate and Normalized Pulse Volume Using Only a Smartphone","volume":"45","author":"Matsumura","year":"2013","journal-title":"Behav. Res. Method."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Peng, R.C., Yan, W.R., Zhang, N.L., Lin, W.H., Zhou, X.L., and Zhang, Y.T. (2016). Investigation of Five Algorithms for Selection of the Optimal Region of Interest in Smartphone Photoplethysmography. J. Sens., 2016.","DOI":"10.1155\/2016\/6830152"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Calvo-Gallego, E., and de Haan, G. (2015, January 11\u201314). Automatic ROI for Remote Photoplethysmography Using PPG and Color Features. 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Technol., in press."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/10\/2385\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:47:54Z","timestamp":1760208474000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/10\/2385"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,10,19]]},"references-count":15,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2017,10]]}},"alternative-id":["s17102385"],"URL":"https:\/\/doi.org\/10.3390\/s17102385","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,10,19]]}}}