{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,4]],"date-time":"2025-12-04T10:02:07Z","timestamp":1764842527100,"version":"build-2065373602"},"reference-count":37,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2021,10,7]],"date-time":"2021-10-07T00:00:00Z","timestamp":1633564800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100016377","name":"Ministerium f\u00fcr Wirtschaft, Innovation, Digitalisierung und Energie des Landes Nordrhein-Westfalen","doi-asserted-by":"publisher","award":["LS-2-2-038a"],"award-info":[{"award-number":["LS-2-2-038a"]}],"id":[{"id":"10.13039\/501100016377","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["LS-2-2-038a"],"award-info":[{"award-number":["LS-2-2-038a"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Background: Biometric sensing is a security method for protecting information and property. State-of-the-art biometric traits are behavioral and physiological in nature. However, they are vulnerable to tampering and forgery. Methods: The proposed approach uses blood flow sounds in the carotid artery as a source of biometric information. A handheld sensing device and an associated desktop application were built. Between 80 and 160 carotid recordings of 11 s in length were acquired from seven individuals each. Wavelet-based signal analysis was performed to assess the potential for biometric applications. Results: The acquired signals per individual proved to be consistent within one carotid sound recording and between multiple recordings spaced by several weeks. The averaged continuous wavelet transform spectra for all cardiac cycles of one recording showed specific spectral characteristics in the time-frequency domain, allowing for the discrimination of individuals, which could potentially serve as an individual fingerprint of the carotid sound. This is also supported by the quantitative analysis consisting of a small convolutional neural network, which was able to differentiate between different users with over 95% accuracy. Conclusion: The proposed approach and processing pipeline appeared promising for the discrimination of individuals. The biometrical recognition could clinically be used to obtain and highlight differences from a previously established personalized audio profile and subsequently could provide information on the source of the deviation as well as on its effects on the individual\u2019s health. The limited number of individuals and recordings require a study in a larger population along with an investigation of the long-term spectral stability of carotid sounds to assess its potential as a biometric marker. Nevertheless, the approach opens the perspective for automatic feature extraction and classification.<\/jats:p>","DOI":"10.3390\/s21196656","type":"journal-article","created":{"date-parts":[[2021,10,10]],"date-time":"2021-10-10T21:37:49Z","timestamp":1633901869000},"page":"6656","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Vascular Auscultation of Carotid Artery: Towards Biometric Identification and Verification of Individuals"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6827-7765","authenticated-orcid":false,"given":"Rutuja","family":"Salvi","sequence":"first","affiliation":[{"name":"IDTM GmbH-Ingenieurgesellschaft f\u00fcr Diagnostischen und Therapeutische Medizintechnik mit Beschr\u00e4nkter Haftung, 45657 Recklinghausen, Germany"}]},{"given":"Patricio","family":"Fuentealba","sequence":"additional","affiliation":[{"name":"IDTM GmbH-Ingenieurgesellschaft f\u00fcr Diagnostischen und Therapeutische Medizintechnik mit Beschr\u00e4nkter Haftung, 45657 Recklinghausen, Germany"},{"name":"Instituto de Electricidad y Electr\u00f3nica, Facultad de Ciencias de la Ingenier\u00eda, Universidad Austral de Chile, Valdivia 5111187, Chile"}]},{"given":"Jasmin","family":"Henze","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Software and Systems Engineering, 44227 Dortmund, Germany"}]},{"given":"Pinar","family":"Bisgin","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Software and Systems Engineering, 44227 Dortmund, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5132-2884","authenticated-orcid":false,"given":"Thomas","family":"S\u00fchn","sequence":"additional","affiliation":[{"name":"INKA-Innovation Laboratory for Image Guided Therapy, Otto-von-Guericke University, 39120 Magdeburg, Germany"},{"name":"SURAG Medical GmbH-Surgical Audio Guidance, 39120 Magdeburg, Germany"}]},{"given":"Moritz","family":"Spiller","sequence":"additional","affiliation":[{"name":"INKA-Innovation Laboratory for Image Guided Therapy, Otto-von-Guericke University, 39120 Magdeburg, Germany"},{"name":"SURAG Medical GmbH-Surgical Audio Guidance, 39120 Magdeburg, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6989-1230","authenticated-orcid":false,"given":"Anja","family":"Burmann","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Software and Systems Engineering, 44227 Dortmund, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5874-7145","authenticated-orcid":false,"given":"Axel","family":"Boese","sequence":"additional","affiliation":[{"name":"MEDICS GmbH-Medical Innovation to Certification Services, 39114 Magdeburg, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0118-0483","authenticated-orcid":false,"given":"Alfredo","family":"Illanes","sequence":"additional","affiliation":[{"name":"INKA-Innovation Laboratory for Image Guided Therapy, Otto-von-Guericke University, 39120 Magdeburg, Germany"},{"name":"SURAG Medical GmbH-Surgical Audio Guidance, 39120 Magdeburg, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8624-0800","authenticated-orcid":false,"given":"Michael","family":"Friebe","sequence":"additional","affiliation":[{"name":"IDTM GmbH-Ingenieurgesellschaft f\u00fcr Diagnostischen und Therapeutische Medizintechnik mit Beschr\u00e4nkter Haftung, 45657 Recklinghausen, Germany"},{"name":"INKA-Innovation Laboratory for Image Guided Therapy, Otto-von-Guericke University, 39120 Magdeburg, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Babiker, A., Hassan, A., and Mustafa, H. (2017). Heart Sounds Biometric System. J. Biomed. Eng. Med. Devices, 2.","DOI":"10.4172\/2475-7586.1000129"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Stanuch, M., Wodzinski, M., and Skalski, A. (2020). Contact-Free Multispectral Identity Verification System Using Palm Veins and Deep Neural Network. Sensors, 20.","DOI":"10.3390\/s20195695"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"7532","DOI":"10.1109\/ACCESS.2016.2614720","article-title":"Unimodal and Multimodal Biometric Sensing Systems: A Review","volume":"4","author":"Oloyede","year":"2016","journal-title":"IEEE Access"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1109\/TCSVT.2003.818349","article-title":"An Introduction to Biometric Recognition","volume":"14","author":"Jain","year":"2004","journal-title":"IEEE Trans. Circuits Syst. Video Technol."},{"key":"ref_5","first-page":"10","article-title":"A Comparative Study of Biometric Technologies with Reference to Human Interface","volume":"14","year":"2011","journal-title":"Int. J. Comput. Appl."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1504\/IJBM.2010.030415","article-title":"A survey of the effects of aging on biometric identity verification","volume":"2","author":"Lanitis","year":"2010","journal-title":"Int. J. Biometeorol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1001\/jamadermatol.2013.1425","article-title":"Fingerprint changes and verification failure among patients with hand dermatitis","volume":"149","author":"Lee","year":"2013","journal-title":"JAMA Dermatol."},{"key":"ref_8","first-page":"e4040","article-title":"Adermatoglyphia: Barriers to Biometric Identification and the Need for a Standardized Alternative","volume":"11","author":"Sarfraz","year":"2019","journal-title":"Cureus"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Pa\u0142ka, N., and Kowalski, M. (2020). Towards Fingerprint Spoofing Detection in the Terahertz Range. Sensors, 20.","DOI":"10.3390\/s20123379"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"614","DOI":"10.1049\/iet-cvi.2014.0084","article-title":"Face recognition: Challenges, achievements and future directions","volume":"9","author":"Hassaballah","year":"2015","journal-title":"IET Comput. Vision"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.procs.2010.11.013","article-title":"Illumination invariant face recognition: A survey of passive methods","volume":"2","author":"Makwana","year":"2010","journal-title":"Procedia Comput. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Kowalski, M. (2020). A Study on Presentation Attack Detection in Thermal Infrared. Sensors, 20.","DOI":"10.3390\/s20143988"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Mehrotra, H., Vatsa, M., Singh, R., and Majhi, B. (2013). Does iris change over time?. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0078333"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"739","DOI":"10.1007\/s11760-013-0593-4","article-title":"Biometric authentication based on PCG and ECG signals: Present status and future directions","volume":"8","author":"Ahmed","year":"2014","journal-title":"Signal Image Video Process."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1016\/j.eswa.2016.09.030","article-title":"ECG databases for biometric systems: A systematic review","volume":"67","author":"Merone","year":"2017","journal-title":"Expert Syst. Appl."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"596","DOI":"10.1109\/TIFS.2007.902922","article-title":"Biometric Identification Based on Frequency Analysis of Cardiac Sounds","volume":"2","author":"Beritelli","year":"2007","journal-title":"IEEE Trans. Inf. Forensics Secur."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"CHENG, X., Wang, P., and She, C. (2020). Biometric Identification Method for Heart Sound Based on Multimodal Multiscale Dispersion Entropy. Entropy, 22.","DOI":"10.3390\/e22020238"},{"key":"ref_18","unstructured":"Lucerna, A., and Espinosa, J. (2021). StatPearls: Carotid Bruit, StatPearls Publishing."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/0002-9610(82)90509-8","article-title":"Diagnosis of carotid stenosis by bruit spectral analysis","volume":"144","author":"Baker","year":"1982","journal-title":"Am. J. Surg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1124","DOI":"10.1056\/NEJM197511272932205","article-title":"Evaluation of carotid stenosis by phonoangiography","volume":"293","author":"Duncan","year":"1975","journal-title":"N. Engl. J. Med."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Majerus, S.J.A., Knauss, T., Mandal, S., Vince, G., and Damaser, M.S. (2018, January 18\u201321). Bruit-enhancing phonoangiogram filter using sub-band autoregressive linear predictive coding. Proceedings of the 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Honolulu, HI, USA.","DOI":"10.1109\/EMBC.2018.8512588"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"29","DOI":"10.2147\/MDER.S135882","article-title":"Digital stethoscope: Technology update","volume":"11","author":"Swarup","year":"2018","journal-title":"Med. Devices"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e000594","DOI":"10.1161\/JAHA.113.000594","article-title":"Association of physical activity in childhood and early adulthood with carotid artery elasticity 21 years later: The cardiovascular risk in Young Finns Study","volume":"3","author":"Pahkala","year":"2014","journal-title":"J. Am. Heart Assoc."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Grossmann, A., Kronland-Martinet, R., and Morlet, J. (1990). Reading and understanding continuous wavelet transforms. Wavelets, Springer.","DOI":"10.1007\/978-3-642-75988-8_1"},{"key":"ref_25","first-page":"258","article-title":"Investigation of signal characteristics using the continuous wavelet transform","volume":"17","author":"Sadowsky","year":"1996","journal-title":"Johns Hopkins Apl Tech. Dig."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1515\/cdbme-2019-0044","article-title":"Computer assisted auscultation system for phonoangiography of the carotid artery","volume":"5","author":"Mahmoodian","year":"2019","journal-title":"Curr. Dir. Biomed. Eng."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"349","DOI":"10.2147\/MDER.S268057","article-title":"Auscultation System for Acquisition of Vascular Sounds\u2014Towards Sound-Based Monitoring of the Carotid Artery","volume":"13","author":"Spiller","year":"2020","journal-title":"Med. Devices"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1023\/A:1015075101937","article-title":"Comparison of wavelet transform and FFT methods in the analysis of EEG signals","volume":"26","author":"Akin","year":"2002","journal-title":"J. Med. Syst."},{"key":"ref_29","unstructured":"Douglas, G., Nicol, F., and Robertson, C. (2013). Macleod\u2019s Clinical Examination E-Book, Elsevier Health Sciences."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3226","DOI":"10.1161\/STROKEAHA.114.005202","article-title":"Atherosclerotic plaque in the left carotid artery is more vulnerable than in the right","volume":"45","author":"Selwaness","year":"2014","journal-title":"Stroke"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1161\/01.HYP.0000077983.66161.6F","article-title":"Is there a side predilection for cerebrovascular disease?","volume":"42","author":"Kroon","year":"2003","journal-title":"Hypertension"},{"key":"ref_32","first-page":"822","article-title":"Logistic regression-HSMM-based heart sound segmentation","volume":"63","author":"Springer","year":"2015","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1016\/j.patrec.2018.03.028","article-title":"Deep-ECG: Convolutional neural networks for ECG biometric recognition","volume":"126","author":"Labati","year":"2019","journal-title":"Pattern Recognit. Lett."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.neucom.2020.01.019","article-title":"Toward improving ECG biometric identification using cascaded convolutional neural networks","volume":"391","author":"Li","year":"2020","journal-title":"Neurocomputing"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Kirchner, J., Faghih-Naini, S., Bisgin, P., and Fischer, G. (2018, January 28\u201331). Sensor selection for classification of physical activity in long-term wearable devices. Proceedings of the 2018 IEEE SENSORS, New Delhi, India.","DOI":"10.1109\/ICSENS.2018.8589663"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Bisgin, P., Houta, S., Burmann, A., and Lenfers, T. (2020, January 8\u201310). REM Sleep Stage Detection of Parkinson\u2019s Disease Patients with RBD. Proceedings of the International Conference on Business Information Systems, Colorado Springs, CO, USA.","DOI":"10.1007\/978-3-030-53337-3_3"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"45","DOI":"10.4103\/0301-4738.37595","article-title":"Understanding and using sensitivity, specificity and predictive values","volume":"56","author":"Parikh","year":"2008","journal-title":"Indian J. Ophthalmol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/19\/6656\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:10:05Z","timestamp":1760166605000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/19\/6656"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,10,7]]},"references-count":37,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2021,10]]}},"alternative-id":["s21196656"],"URL":"https:\/\/doi.org\/10.3390\/s21196656","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2021,10,7]]}}}