Wearable photoplethysmographic sensors—past and present
Open accessAbstract
Photoplethysmography (PPG) technology has been used to develop small, wearable, pulse rate sensors. These devices, consisting of infrared light-emitting diodes (LEDs) and photodetectors, offer a simple, reliable, low-cost means of monitoring the pulse rate noninvasively. Recent advances in optical technology have facilitated the use of high-intensity green LEDs for PPG, increasing the adoption of this measurement technique. In this review, we briefly present the history of PPG and recent developments in wearable pulse rate sensors with green LEDs. The application of wearable pulse rate monitors is discussed.
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Motion artifacts may manifest as missing or false beats, which result in incorrect heart rate calculations.
“Motion artifacts may manifest as missing or false beats which result in incorrect HR calculations.”
From Investigating sources of inaccuracy in wearable optical heart rate sensors (2020) · cites this paper as [37]
Section 3.4.4.3 (page unavailable) reports heart-rate estimation errors in motion-corrupted PPG signals and reductions in those errors after artifact removal. The copy does not describe motion artifacts as missing or false beats, so it supports the effect on heart-rate calculations but not the claimed manifestation. (LLM, conf=0.86)
Experimental — accuracy not yet measuredGreen-wavelength pulse oximeters display the greatest modulation depth with pulsatile blood absorption, i.e., a greater absorbance for both deoxyhemoglobin and oxyhemoglobin than infrared light.
“Green-wavelength pulse oximeters display the greatest modulation depth with pulsatile blood absorption, i.e., a greater absorbance for both deoxyhemoglobin and oxyhemoglobin than infrared light [40].”
From Skin pigmentation influence on pulse oximetry accuracy: a systematic review and bibliometric analysis (2022) · cites this paper as [40]
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Cites
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“In addition, by exploiting the independence between PPG and motion artifacts, Kim and Yoo proposed that the combination of ICA and block interleaving with a low-pass filter can reduce the motion artifacts under the conditions used in general dual-wavelength measurements [72].”
BackgroundA Novel Approach for Motion Artifact Reduction in PPG Signals Based on AS-LMS Adaptive Filter
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“A simple, efficient approach, based on the AS-LMS adaptive filter, was applied to reduce motion artifacts in corrupted PPG signals [59].”
MethodSkin photoplethysmography — a review
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Artifact-resistant power-efficient design of finger-ring plethysmographic sensors
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“Adaptive filtering, combined with an improved mechanical design and probe configuration, increased the accuracy of the PPG signal received [14].”
BackgroundMethodA Motion-Tolerant Adaptive Algorithm for Wearable Photoplethysmographic Biosensors
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The advantages of wearable green reflected photoplethysmography
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BackgroundSelf-citationMotion-tolerant magnetic earring sensor and wireless earpiece for wearable photoplethysmography
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Investigating a smartphone imaging unit for photoplethysmography
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“The other is the contact type for short-distance measurements, such as placing the finger on the mobile phone camera to cover the entire camera view and using the phone camera flash LED light (white light) to illuminate the finger [47].”
BackgroundThe effect of contacting force on photoplethysmographic signals
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“Changes in the AC pulse amplitude, DC amplitude, ratio of AC/DC amplitudes and normalized pulse area of the reflected PPG signal have been investigated [35].”
BackgroundReddy, K. A., George, B., & Kumar, V. J. (2008) · IEEE Transactions on Instrumentation and Measurement · doi:10.1109/tim.2008.2009136 · Cited by 165 · cited 1× · see citing works
“Experimental results have verified the efficacy of the proposed method [51].”
MethodBasal perfusion of the cutaneous microcirculation: Measurements as a function of anatomic position
Tur, E., Tur, M., Maibach, H. I., & Guy, R. H. (1983) · Journal of Investigative Dermatology · doi:10.1111/1523-1747.ep12522619 · Cited by 163 · cited 1× · see citing works
“The perfusion values of 52 anatomical sites in healthy subjects showed that the fingers, palm, face, and ears offer much higher perfusion values compared with other measurement sites [33]; the transmitted PPG signal amplitude from the earlobe provides the largest perfusion value.”
BackgroundReduction of motion artifact in pulse oximetry by smoothed pseudo Wigner-Ville distribution
Yan, Y. S., Poon, C. C. Y., & Zhang, Y. (2005) · Journal of NeuroEngineering and Rehabilitation · doi:10.1186/1743-0003-2-3 · Cited by 157 · see citing works
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“, NLMS, RLS, and conventional Kalman filter algorithms), can be used to estimate motion artifact reduction, and has been shown to provide reliable information from the reconstructed PPG signals [63].”
MethodIn vivo reflectance of blood and tissue as a function of light wavelength
Cui, W., Ostrander, L. E., & Lee, B. Y. (1990) · IEEE Transactions on Biomedical Engineering · doi:10.1109/10.55667 · Cited by 149 · cited 1× · see citing works
“However, green-wavelength PPG devices are becoming increasingly popular due to the large intensity variations in modulation observed during the cardiac cycle for these wavelengths [7–9].”
BackgroundA new method for pulse oximetry possessing inherent insensitivity to artifact
Hayes, M. J., & Smith, P. R. (2001) · IEEE Transactions on Biomedical Engineering · doi:10.1109/10.915711 · Cited by 122 · cited 1× · see citing works
“The scope and power of this methodology was investigated based on the results obtained with a practical electronic system [77,78].”
MethodLee, C. M., & Zhang, Y. (2004) · doi:10.1109/apbme.2003.1302650 · Cited by 114 · cited 2× · see citing works
“, wavelet transforms [67] and smoothed pseudo Wigner-Ville distributions [68]) may provide better signal enhancement for PPG signals than traditional methods.”
MethodMultichannel reflective PPG earpiece sensor with passive motion cancellation
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“01 and 10% relative strength compared with the finger-based approach were recorded from superior and posterior auricular skin [25].”
BackgroundResultThe Periodic Moving Average Filter for Removing Motion Artifacts from PPG Signals
Lee, H.-W., Lee, J., Jung, W.-G., & Lee, G.-K. (2007) · International Journal of Control Automation and Systems · Cited by 114 · see citing works
Active noise cancellation using MEMS accelerometers for motion-tolerant wearable bio-sensors
Asada, H. H., Jiang, H.-H., & Gibbs, P. (2005) · Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) · doi:10.1109/iembs.2004.1403631 · Cited by 113 · cited 1× · see citing works
“Figure 5 shows a motion-tolerant wearable biosensor using a MEMS accelerometer [52,53], which operates based on adaptive noise cancellation utilizing an acceleration reference.”
MethodChan, K. W., & Zhang, Y. (2003) · Proceedings of IEEE Sensors/Proceedings of IEEE Sensors ... · doi:10.1109/icsens.2002.1037314 · Cited by 104 · cited 1× · see citing works
“A LMS filter with automatic step-size control was used to mitigate the effects of motion artifacts in PPG recordings for long-term patient monitoring [54].”
MethodDevelopment of real-time motion artifact reduction algorithm for a wearable photoplethysmography
Han, H., Kim, M.-J., & Kim, J. (2007) · 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society · doi:10.1109/iembs.2007.4352596 · Cited by 101 · cited 1× · see citing works
“In another study, a two-dimensional (2-D) active noise cancellation algorithm was applied to compensate for motion-distorted signals using directional accelerometer data [55]; a NLMS adaptive filter (fourth-order) was used in the algorithm, resulting in a reduction in signal distortion from 52.”
MethodCardiovascular Monitoring Using Earphones and a Mobile Device
Poh, M., Kim, K., Goessling, A. D., Swenson, N. C., & Picard, R. W. (2010) · IEEE Pervasive Computing · doi:10.1109/mprv.2010.91 · Cited by 92 · cited 1× · see citing works
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Han, H., & Kim, J. (2011) · Computers in Biology and Medicine · doi:10.1016/j.compbiomed.2011.12.005 · Cited by 92 · cited 1× · see citing works
“In one study, the correlations among six representative daily motions and patterns of motion artifacts were examined to obtain more precise analysis [58].”
BackgroundDesign of filter to reject motion artifact of pulse oximetry
Lee, J., Jung, W.-G., Kang, I., Kim, Y., & Lee, G.-K. (2003) · Computer Standards & Interfaces · doi:10.1016/s0920-5489(03)00077-1 · Cited by 91 · cited 2× · see citing works
“Instead, motion artifacts can be removed using a filter bank and a matched filter consisting of several frequency bands [50].”
BackgroundA Flexible, Low Noise Reflective PPG Sensor Platform for Ear-Worn Heart Rate Monitoring
Patterson, J. A. C., McIlwraith, D. C., & Yang, G.-Z. (2009) · 2009 Sixth International Workshop on Wearable and Implantable Body Sensor Networks · doi:10.1109/bsn.2009.16 · Cited by 91 · cited 1× · see citing works
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Feasibility of Imaging Photoplethysmography
Zheng, J., Hu, S., Chouliaras, V. A., & Summers, R. (2008) · International Conference on Biomedical Engineering and Informatics (BMEI) · doi:10.1109/bmei.2008.365 · Cited by 84 · cited 1× · see citing works
“Plethysmographic signals can be measured remotely (>1 m) using ambient light and PD with either a simple consumer-level digital camera in movie mode or a cellular phone [11,44–46].”
MethodYao, J., & Warren, S. (2005) · Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) · doi:10.1109/iembs.2005.1617256 · Cited by 83 · cited 1× · see citing works
“Analyses have indicated that motion significantly affects arterial flow, so care must be taken when applying ICA to light-based sensor data acquired from wearable platforms [71].”
BackgroundOptical noninvasive monitoring of skin blood pulsations
Spīgulis, J. (2005) · Applied Optics · doi:10.1364/ao.44.001850 · Cited by 75 · cited 1× · see citing works
“8 N was applied to the finger [36].”
MethodMendelson, Y., & Pujary, C. J. (2004) · doi:10.1109/iembs.2003.1280775 · Cited by 74 · cited 2× · see citing works
“Forehead sensors have shown greater sensitivity to pulsatile signal changes under low perfusion conditions, compared with other peripheral body locations [31].”
BackgroundArtifact reduction in photoplethysmography
Hayes, M., & Smith, P. R. (1998) · Applied Optics · doi:10.1364/ao.37.007437 · Cited by 71 · cited 1× · see citing works
“The scope and power of this methodology was investigated based on the results obtained with a practical electronic system [77,78].”
MethodFoo, J. Y. A. (2006) · Biomedical Signal Processing and Control · doi:10.1016/j.bspc.2006.01.001 · Cited by 70 · cited 1× · see citing works
“A comparative study in the efficiency of wavelet transform and adaptive filtering techniques for restoring artifact-reduced PPG signals for heart rate estimations revealed that both methods introduce a phase shift to the PPG signals [69,70].”
MethodIn-Ear Vital Signs Monitoring Using a Novel Microoptic Reflective Sensor
Vogel, S., Hülsbusch, M., Hennig, T., Blažek, V., & Leonhardt, S. K. (2009) · IEEE Transactions on Information Technology in Biomedicine · doi:10.1109/titb.2009.2033268 · Cited by 68 · cited 1× · see citing works
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Budidha, K., & Kyriacou, P. A. (2014) · Physiological Measurement · doi:10.1088/0967-3334/35/2/111 · Cited by 67 · cited 3× · see citing works
“Earpiece PPG sensor (with permission [24]).”
BackgroundKalman Filter Based Adaptive Reduction Of Motion Artifact From Photoplethysmographic Signal
Seyedtabaii, S., & Seyedtabaii, L. (2008) · Zenodo (CERN European Organization for Nuclear Research) · doi:10.5281/zenodo.1333655 · Cited by 59 · see citing works
Wood, L. B., & Asada, H. H. (2007) · Conference proceedings · doi:10.1109/iembs.2007.4352374 · Cited by 52 · cited 1× · see citing works
“Time domain data shows how a Laguerre model outperforms a FIR model in accordance with computed model variance [75].”
MethodEsophageal pulse oximetry utilizing reflectance photoplethysmography
Kyriacou, P. A., Powell, S., Langford, R. M., & Jones, D. P. (2002) · IEEE Transactions on Biomedical Engineering · doi:10.1109/tbme.2002.804584 · Cited by 51 · cited 1× · see citing works
“In addition, the esophageal region has been used in clinical practice [28–30].”
MethodBiomedical Sensors and Instruments
Tagawa, T., TAMURA, T., & Öberg, P. Å. (2011) · CRC Press eBooks · doi:10.1201/b10775 · Cited by 51 · see citing works
ZigBee Device Access Control and Reliable Data Transmission in ZigBee Based Health Monitoring System
Jung, J.-W., & Lee, J. (2008) · International Conference on Advanced Communication Technology · doi:10.1109/icact.2008.4493875 · Cited by 49 · cited 1× · see citing works
“In recent years, different measurement sites for PPG sensors have been explored extensively, including the ring finger [14], wrist [15,16], brachia [9,17,18], earlobe [19–21], external ear cartilage [22–24], and the superior auricular region [25–27].”
BackgroundEffect of probe contact pressure on the photoplethysmographic assessment of conduit artery stiffness
Grabovskis, A., Marcinkevics, Z., Rubins, U., & Kviesis-Kipge, E. (2013) · Journal of Biomedical Optics · doi:10.1117/1.jbo.18.2.027004 · Cited by 47 · cited 2× · see citing works
“To determine the optimal contact pressure, one group obtained in vivo PPG readings from conduit artery sites in five healthy subjects recorded with probe contact pressures ranging from 0 to 15 kPa [43].”
MethodPulsed multifrequency photoplethysmograph
Giltvedt, J., Sira, A., & Helme, P. (1984) · Medical & Biological Engineering & Computing · doi:10.1007/bf02442745 · Cited by 47 · cited 1× · see citing works
“Thus, IR light has been used in PPG devices for some time [6].”
MethodHsiu, H., Hsu, C.-L., & Wu, T.-L. (2011) · Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine · doi:10.1177/0954411910396288 · Cited by 46 · cited 1× · see citing works
“In one particular study, blood pressure and finger PPG waveforms were simultaneously measured in healthy volunteers under different contact pressures ranging from 0 to 200 mmHg [42].”
MethodA New Wristband Wearable Sensor Using Adaptive Reduction Filter to Reduce Motion Artifact
Wei, P., Guo, R., Zhang, J., & Zhang, Y. (2008) · IEEE International Conference on Information Technology and Applications in Biomedicine · doi:10.1109/itab.2008.4570636 · Cited by 44 · cited 2× · see citing works
“In another study, a triaxial MEMS accelerometer was attached to a PPG sensor to detect wrist movement [56].”
BackgroundMethodDevelopment of a wristwatch-type PPG array sensor module
Lee, Y., Shin, H., Jo, J. H., & Lee, Y.-K. (2011) · IEEE International Conference on Consumer Electronics - Berlin (ICCE-Berlin) · doi:10.1109/icce-berlin.2011.6031811 · Cited by 41 · cited 3× · see citing works
“In the experiments, the proposed module was assessed and compared with the commercially available product produced by BIOPAC [16].”
BackgroundMethodInfluentialGibbs, P., Wood, L. B., & Asada, H. H. (2005) · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · doi:10.1117/12.600781 · Cited by 41 · cited 1× · see citing works
“Figure 5 shows a motion-tolerant wearable biosensor using a MEMS accelerometer [52,53], which operates based on adaptive noise cancellation utilizing an acceleration reference.”
MethodReflectance pulse oximetry at the forehead improves by pressure on the probe
Dassel, A. C. M., Graaff, R., Sikkema, M., Meijer, A., Zijlstra, W. G., & Aarnoudse, J. G. (1995) · The Journal of Clinical Monitoring · doi:10.1007/bf01617518 · Cited by 40 · cited 1× · see citing works
“Note that in SpO2 studies, the ratio between the relative change in the red and IR light intensities (R/IR) was used to indicate accurate oxygen saturation; R/IR values varied from 0 to 80 mmHg for the forehead of a newborn infant, with a portion of the PPG signal derived from tissue underneath the skull [39–41].”
MethodWood, L. B., & Asada, H. H. (2006) · 2006 International Conference of the IEEE Engineering in Medicine and Biology Society · doi:10.1109/iembs.2006.260359 · Cited by 39 · cited 1× · see citing works
“6% [74].”
Direct Pulse Oximetry Within the Esophagus, on the Surface of Abdominal Viscera, and on Free Flaps
Kyriacou, P. A. (2013) · Anesthesia & Analgesia · doi:10.1213/ane.0b013e3182a1bef6 · Cited by 30 · see citing works
A system for investigating oesophageal photoplethysmographic signals in anaesthetised patients
Kyriacou, P. A., Moye, A. R., Gregg, A., Choi, D. M., Langford, R. M., & Jones, D. P. (1999) · Medical & Biological Engineering & Computing · doi:10.1007/bf02513360 · Cited by 29 · cited 1× · see citing works
“In addition, the esophageal region has been used in clinical practice [28–30].”
MethodDassel, A. C. M., Graaff, R., Meijer, A., Zijlstra, W. G., & Aarnoudse, J. G. (1996) · The Journal of Clinical Monitoring · doi:10.1007/bf02199702 · Cited by 28 · cited 1× · see citing works
“Note that in SpO2 studies, the ratio between the relative change in the red and IR light intensities (R/IR) was used to indicate accurate oxygen saturation; R/IR values varied from 0 to 80 mmHg for the forehead of a newborn infant, with a portion of the PPG signal derived from tissue underneath the skull [39–41].”
MethodProcessing of Pulse Oximeter Data Using Discrete Wavelet Analysis
Lee, S., Ibey, B. L., Xü, W., Wilson, M. A., Ericson, M. N., & Coté, G. L. (2005) · IEEE Transactions on Biomedical Engineering · doi:10.1109/tbme.2005.847538 · Cited by 27 · cited 2× · see citing works
“In this study [69], data were acquired from both in vitro and in vivo sources: a perfusion model and the proximal jejunum of an adult pig.”
MethodEffect of location of the sensor on reflectance pulse oximetry
Dassel, A. C. M., Graaff, R., Aardema, M. W., Zijlstra, W. G., & Aarnoudse, J. G. (1997) · BJOG An International Journal of Obstetrics & Gynaecology · doi:10.1111/j.1471-0528.1997.tb14350.x · Cited by 22 · cited 1× · see citing works
“Note that in SpO2 studies, the ratio between the relative change in the red and IR light intensities (R/IR) was used to indicate accurate oxygen saturation; R/IR values varied from 0 to 80 mmHg for the forehead of a newborn infant, with a portion of the PPG signal derived from tissue underneath the skull [39–41].”
MethodLee, B., Kee, Y., Han, J., & Yi, W. J. (2011) · Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) · doi:10.1109/iembs.2011.6091957 · Cited by 18 · cited 1× · see citing works
“signals [61].”
A Novel Headset with a Transmissive PPG Sensor for Heart Rate Measurement
Shin, K., Kim, Y., Bae, S., Park, K., & Kim, S. (2009) · World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany · doi:10.1007/978-3-540-92841-6_127 · Cited by 17 · cited 2× · see citing works
“Year published 2009 [20] 2008 [26] 2007 [19] 2009 [27] 2010 [22] 2012 [24] 2004 [23] 2009 [21]”
BackgroundActive Motion Artifact Reduction for Wearable Sensors Using Laguerre Expansion and Signal Separation
Wood, L. B., & Asada, H. H. (2005) · doi:10.1109/iembs.2005.1617251 · Cited by 17 · cited 3× · see citing works
“The experimental results indicated that the active noise cancellation method was capable of recovering ring PPG sensor signals corrupted with 2G acceleration in the longitudinal direction of the digital artery [76].”
BackgroundMethodInfluentialHome-Telecare of the elderly living alone using an new designed ear-wearable sensor
Wang, C., & Zheng, Y. (2008) · IEEE/EMBS International Summer School on Medical Devices and Biosensors (ISSS-MDBS) · doi:10.1109/issmdbs.2008.4575019 · Cited by 16 · cited 1× · see citing works
“Year published 2009 [20] 2008 [26] 2007 [19] 2009 [27] 2010 [22] 2012 [24] 2004 [23] 2009 [21]”
Particle filter-based noise reduction of PPG signals for robust emotion recognition
Lee, Y.-K., Jo, J. H., Lee, Y., Shin, H. S., & Kwon, O. (2012) · International Conference on Consumer Electronics · doi:10.1109/icce.2012.6162034 · Cited by 14 · cited 1× · see citing works
“2%) for arm movement and walking, respectively, compared with the conventional NLMS algorithm (conventional Kalman filter-based algorithm) [65]; the output SNR improved by 4.”
MethodOptical non-invasive monitoring of skin blood pulsations
Spīgulis, J. (2005) · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · doi:10.1117/12.639414 · Cited by 13 · see citing works
Wood, L. B. (2008) · DSpace@MIT (Massachusetts Institute of Technology) · Cited by 11 · see citing works
Glass-type wireless PPG measuring system
Lee, E.-T., Shin, J.-I., Hong, J. H., Cha, E. J., & Lee, T. S. (2010) · Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) · doi:10.1109/iembs.2010.5626704 · Cited by 10 · cited 2× · see citing works
“In addition, use of a glass-type wireless PPG has been examined [32].”
BackgroundMethodKim, S. C., Hwang, E. J., & Kim, D. W. (2007) · Springer eBooks · doi:10.1007/978-3-540-36841-0_287 · Cited by 7 · cited 1× · see citing works
“Similarly, an adaptive scaled Fourier linear combiner (SFLC) was used to reduce motion artifacts in PPG signals without the need for additional sensors [62].”
MethodThe Effect of Contact Pressure to the Photoplethysmographic Sensor During Walking
Maeda, Y., Sekine, M., TAMURA, T., & Mizutani, K. (2013) · Seitai ikougaku/Seitai ikogaku · doi:10.11239/jsmbe.51.r-307 · Cited by 7 · cited 1× · see citing works
“A similar contact force study was conducted on the upper arm [37]; an average compression pressure of 30 mmHg (4 kPa) produced a PPG peak amplitude for IR and green light sources.”
MethodThe Design And Clinical Use Of A Reflective Brachial Photoplethysmograph
Maguire, M. F., & Ward, T. E. (2002) · Maynooth University ePrints and eTheses Archive (Maynooth University) · Cited by 6 · see citing works
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Wearable Sensors for Human Activity Monitoring: A Review
Mukhopadhyay, S. C. (2015) · IEEE Sensors Journal · doi:10.1109/jsen.2014.2370945 · Cited by 1,401 · see citing works
“based technology [23], [24], sound based [25], based on”
BackgroundGhamari, M. (2018) · International Journal of Biosensors & Bioelectronics · doi:10.15406/ijbsbe.2018.04.00125 · Cited by 945 · see citing works
Toward ubiquitous blood pressure monitoring via pulse transit time: Theory and practice
Mukkamala, R., Hahn, J.-O., Inan, O. T., Mestha, L. K., Kim, C.-S., Toreyin, H., & Kyal, S. (2015) · IEEE Transactions on Biomedical Engineering · doi:10.1109/tbme.2015.2441951 · Cited by 935 · see citing works
“The advantage of reflectance-mode PPG is that it is less restrictive in terms of measurement locations [66], [67], [69].”
BackgroundMethodInfluentialWearable health devices-vital sign monitoring, systems and technologies
Dias, D., & Paulo Silva Cunha, J. (2018) · Sensors · doi:10.3390/s18082414 · Cited by 919 · see citing works
“One of the problems in blood oxygen saturation measurement is when the patient is anemic [13,38,39].”
BackgroundInvestigating sources of inaccuracy in wearable optical heart rate sensors
Bent, B., Goldstein, B. A., Kibbe, W. A., & Dunn, J. P. (2020) · npj Digital Medicine · doi:10.1038/s41746-020-0226-6 · Cited by 673 · see citing works
Human Emotion Recognition: Review of Sensors and Methods
Dzedzickis, A., Kaklauskas, A., & Bučinskas, V. (2020) · Sensors · doi:10.3390/s20030592 · Cited by 596 · see citing works
“(i) the static part of signal depends on the structure of the tissue and the average blood volume arterial and venous blood, and it varies very slowly depending on respiration; (ii) the dynamic part represents changes in the blood volume that occurs between the systolic and diastolic phases of the cardiac cycle [104].”
BackgroundInfluentialPhotoplethysmography Revisited: From Contact to Noncontact, From Point to Imaging
Sun, Y., & Thakor, N. V. (2015) · IEEE Transactions on Biomedical Engineering · doi:10.1109/tbme.2015.2476337 · Cited by 567 · see citing works
Hong, Y. J., Jeong, H., Cho, K. W., Lu, N., & Kim, D. (2019) · Advanced Functional Materials · doi:10.1002/adfm.201808247 · Cited by 559 · see citing works
Self‐Powered Pulse Sensor for Antidiastole of Cardiovascular Disease
Ouyang, H., Tian, J., Sun, G., Zou, Y., Liu, Z., Li, H., Zhao, L., Shi, B., Fan, Y., Fan, Y., et al. (2017) · Advanced Materials · doi:10.1002/adma.201703456 · Cited by 468 · see citing works
Flexible Wearable Sensors for Cardiovascular Health Monitoring
Chen, S., Qi, J., Fan, S., Qiao, Z., Yeo, J. C., & Lim, C. T. (2021) · Advanced Healthcare Materials · doi:10.1002/adhm.202100116 · Cited by 453 · see citing works
Contact-Based Methods for Measuring Respiratory Rate
Massaroni, C., Nicolò, A., Presti, D. L., Sacchetti, M., Silvestri, S., & Schena, E. (2019) · Sensors · doi:10.3390/s19040908 · Cited by 442 · see citing works
“, the green-yellow region of the visible spectrum) at the tissue [233], and (ii) one photodetector, PD, to record the intensity of the non-absorbed light reflected from the tissue [246].”
BackgroundMethodOrganic Light‐Emitting Diodes: Pushing Toward the Limits and Beyond
Song, J., Lee, H., Jeong, E. G., Choi, K. C., & Yoo, S. (2020) · Advanced Materials · doi:10.1002/adma.201907539 · Cited by 412 · see citing works
Zhang, Z. (2015) · IEEE Transactions on Biomedical Engineering · doi:10.1109/tbme.2015.2406332 · Cited by 388 · see citing works
“W ITH the emerging of smart watches and smart wristbands for healthcare and fitness, heart rate (HR) monitoring using photoplethysmography (PPG) [1], [2] recorded from wearers’ wrists becomes a new research topic both in industry and academia.”
BackgroundReview on Wearable Technology Sensors Used in Consumer Sport Applications
Aroganam, G., Manivannan, N., & Harrison, D. (2019) · Sensors · doi:10.3390/s19091983 · Cited by 370 · see citing works
“Initially, there is no current, thus every time the hammer connects to the other side, an open circuit becomes closed.”
BackgroundSources of inaccuracy in photoplethysmography for continuous cardiovascular monitoring
Fine, J., Branan, K. L., Rodriguez, A. J., Boonya-ananta, T., Ajmal, Ramella-Roman, J. C., McShane, M. J., & Coté, G. L. (2021) · Biosensors · doi:10.3390/bios11040126 · Cited by 348 · see citing works
Skin bioelectronics towards long-term, continuous health monitoring
Wang, Y., Haick, H., Guo, S., Wang, C., Lee, S., Yokota, T., & Someya, T. (2022) · Chemical Society Reviews · doi:10.1039/d2cs00207h · Cited by 320 · see citing works
Photoplethysmography based atrial fibrillation detection: a review
Pereira, T., Tran, N., Gadhoumi, K., Pelter, M. M., Do, D. H., Lee, R. J., Colorado, R., Meisel, K., & Hu, X. (2020) · npj Digital Medicine · doi:10.1038/s41746-019-0207-9 · Cited by 300 · see citing works
Flexible graphene photodetectors for wearable fitness monitoring
Polat, E. O., Mercier, G., Nikitskiy, I., Puma, E., Galán, T., Gupta, S., Marques, M. M., Piqueras, J. J., Bouwens, M., Durduran, T., et al. (2019) · Science Advances · doi:10.1126/sciadv.aaw7846 · Cited by 299 · see citing works
Lee, H., Kim, E., Lee, Y., Kim, H., Lee, J., Kim, M., Yoo, H., & Yoo, S. (2018) · Science Advances · doi:10.1126/sciadv.aas9530 · Cited by 277 · see citing works
“It is based on a reflective configuration, and thus, light sources and detectors are on the same plane (15).”
BackgroundSensors and Functionalities of Non-Invasive Wrist-Wearable Devices: A Review
Kamišalić, A., Fister, I., Turkanović, M., & Karakatič, S. (2018) · Sensors · doi:10.3390/s18061714 · Cited by 272 · see citing works
“Heart rate is mostly measured using a PPG sensor, which is mostly based on finger measurements sites in commercial solutions [72].”
MethodHeart Rate Estimation From Wrist-Worn Photoplethysmography: A Review
Biswas, D., Simões‐Capela, N., Hoof, C. A. V., & Helleputte, N. V. (2019) · IEEE Sensors Journal · doi:10.1109/jsen.2019.2914166 · Cited by 263 · see citing works
Khan, S., Ali, S., & Bermak, A. (2019) · Sensors · doi:10.3390/s19051230 · Cited by 256 · see citing works
Current progress of photoplethysmography and SPO2 for health monitoring
TAMURA, T. (2019) · Biomedical Engineering Letters · doi:10.1007/s13534-019-00097-w · Cited by 260 · see citing works
A new look at the essence of the imaging photoplethysmography
Kamshilin, A. A., Nippolainen, E., Sidorov, I. S., Васильев, П. В., Ерофеев, Н. П., Podolyan, N. P., & Владимирович, Р. Р. (2015) · Scientific Reports · doi:10.1038/srep10494 · Cited by 250 · see citing works
Soft Bioelectronics Based on Nanomaterials
Cho, K. W., Sunwoo, S., Hong, Y. J., Koo, J. H., Kim, J. H., Baik, S., Hyeon, T., & Kim, D. (2021) · Chemical Reviews · doi:10.1021/acs.chemrev.1c00531 · Cited by 247 · see citing works
Blood pressure estimation from appropriate and inappropriate PPG signals using A whole-based method
Mousavi, S. S., Firouzmand, M., Charmi, M., Hemmati, M. R., Moghadam, M., & Ghorbani, Y. (2018) · Biomedical Signal Processing and Control · doi:10.1016/j.bspc.2018.08.022 · Cited by 234 · see citing works
A Rigid-Flex Wearable Health Monitoring Sensor Patch for IoT-Connected Healthcare Applications
Wu, T., Wu, F., Qiu, C., Redouté, J., & Yuce, M. R. (2020) · IEEE Internet of Things Journal · doi:10.1109/jiot.2020.2977164 · Cited by 230 · see citing works
“As the blood volume in vessels varies during the systolic and diastolic phase of a heartbeat, the light intensity variation detected by the PD is in the same frequency of the HR [41].”
BackgroundKim, K. B., & Baek, H. J. (2023) · Electronics · doi:10.3390/electronics12132923 · Cited by 238 · see citing works
“In early 2010, as wrist-wearable devices with PPG sensors began to be commercialized, a review of wearable PPG systems was published in the journal Electronics [16].”
Wearable-Based Affect Recognition—A Review
Schmidt, P., Reiss, A., Dürichen, R., & Laerhoven, K. V. (2019) · Sensors · doi:10.3390/s19194079 · Cited by 267 · see citing works
“Hence, the cardiac cycle is captured by the PPG signal, where the pulsatile part of the PPG signal reflects the pulsatile component in arterial blood flow [61].”
Dieffenderfer, J., Goodell, H., Mills, S., McKnight, M., Yao, S., Lin, F., Beppler, E., Bent, B., Lee, B., Misra, V., et al. (2016) · IEEE Journal of Biomedical and Health Informatics · doi:10.1109/jbhi.2016.2573286 · Cited by 212 · see citing works
“normalized least means square (NLMS) adaptive filtering algorithm [42], [43] was used to remove the noise distortion from the physiological signal where the noise is highly correlated”
Human Vital Signs Detection Methods and Potential Using Radars: A Review
Kebe, M., Gadhafi, R., Mohammad, B. S., Sanduleanu, M., Saleh, H. H., & Al‐Qutayri, M. (2020) · Sensors · doi:10.3390/s20051454 · Cited by 208 · see citing works
“At least one light-emitting-diode (LED) in direct contact with the tissue is used to emit light with wavelengths between 500 nm and 600 nm, corresponding to the green and yellow regions [36,37].”
InfluentialFlexible and Stretchable Light-Emitting Diodes and Photodetectors for Human-Centric Optoelectronics
Chang, S., Koo, J. H., Yoo, J., Kim, M. S., Choi, M. K., Kim, D., & Song, Y. M. (2024) · Chemical Reviews · doi:10.1021/acs.chemrev.3c00548 · Cited by 209 · see citing works
Lo, L.-W., Zhao, J., Wan, H., Wang, Y., Chakrabartty, S., & Wang, C. (2021) · ACS Applied Materials & Interfaces · doi:10.1021/acsami.1c00537 · Cited by 199 · see citing works
Zeagler, C. (2017) · ACM International Symposium on Wearable Computers (ISWC) · doi:10.1145/3123021.3123042 · Cited by 204 · see citing works
Diagnostic Features and Potential Applications of PPG Signal in Healthcare: A Systematic Review
Almarshad, M. A., Islam, M. S., Al-Ahmadi, S. A., & BaHammam, A. S. (2022) · Healthcare · doi:10.3390/healthcare10030547 · Cited by 200 · see citing works
“Some of them focus on the specific medical use of PPG like pulse rate [3], blood pressure [4,5], atrial fibrillation [6,7], circulatory monitoring [8], nociception [9], or on the specific placement of PPG [10,11], others instead focused on reviewing the way that the signal has been analyzed [7,12–16] or the type of th…”
BackgroundEmotion Recognition from Multimodal Physiological Signals for Emotion Aware Healthcare Systems
Ayata, D., Yaslan, Y., & Kamasak, M. E. (2020) · Journal of Medical and Biological Engineering · doi:10.1007/s40846-019-00505-7 · Cited by 182 · see citing works
Milstein, N., & Gordon, I. (2020) · Frontiers in Behavioral Neuroscience · doi:10.3389/fnbeh.2020.00148 · Cited by 180 · see citing works
“We imported the raw data obtained from the E4 wristband into Kubios, after it was organized to fit Kubios’ specifications with MATLAB 2018a. Kubios HRV Premium software includes an adaptive QRS detection algorithm, pulse wave detectors and tools for automatic and threshold based artifact correction, trend removal and…”
MethodInfluentialCuffless Blood Pressure Measurement
Mukkamala, R., Stergiou, G. S., & Avolio, A. P. (2022) · Annual Review of Biomedical Engineering · doi:10.1146/annurev-bioeng-110220-014644 · Cited by 180 · see citing works
Wristband-type wearable health devices to measure construction workers' physical demands
Hwang, S., & Lee, S. H. (2017) · Automation in Construction · doi:10.1016/j.autcon.2017.06.003 · Cited by 169 · see citing works
Wearable activity trackers–advanced technology or advanced marketing?
Shei, R., Holder, I. G., Oumsang, A. S., Paris, B. A., & Paris, H. L. R. (2022) · European Journal of Applied Physiology · doi:10.1007/s00421-022-04951-1 · Cited by 169 · see citing works
“Transmission of light through the tissue, or reflection of light from the tissue, alter light intensity and are associated with changes in tissue perfusion (Tamura et al. 2014).”
BackgroundWearable Hardware Design for the Internet of Medical Things (IoMT)
Qureshi, F., & Krishnan, S. (2018) · Italian National Conference on Sensors · doi:10.3390/s18113812 · Cited by 128 · see citing works
A Review of Wearable Multi-Wavelength Photoplethysmography
Ray, D., Collins, T., Woolley, S., & Ponnapalli, P. (2023) · IEEE Reviews in Biomedical Engineering · doi:10.1109/rbme.2021.3121476 · Cited by 155 · see citing works
“At this point the amplitude of the pulsatile component of the signal starts to decrease as the external pressure increases until circulation is cut off due to the flattening of the arterial walls [78], [83], [109].”
BackgroundResultInfluentialFlexible heartbeat sensor for wearable device
Kwak, Y. H., Kim, W.-H., Park, K.-B., Kim, K., & Seo, S. (2017) · Biosensors and Bioelectronics · doi:10.1016/j.bios.2017.03.016 · Cited by 151 · see citing works
Local Group Invariance for Heart Rate Estimation from Face Videos in the Wild
Pilz, C. S., Zaunseder, S., Krajewski, J., & Blažek, V. (2018) · IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW) · doi:10.1109/cvprw.2018.00172 · Cited by 149 · see citing works
Novel Wearable Optical Sensors for Vital Health Monitoring Systems—A Review
Kaur, B., Kumar, S., & Kaushik, B. K. (2023) · Biosensors · doi:10.3390/bios13020181 · Cited by 152 · see citing works
“sion from Electron, Copyright 2014, MDPI [65].”
MethodInfluentialMotion Artifact Removal Techniques for Wearable EEG and PPG Sensor Systems
Seok, D., Lee, S.-H., Kim, M., Cho, J., & Kim, C. (2021) · Frontiers in Electronics · doi:10.3389/felec.2021.685513 · Cited by 148 · see citing works
“MindWave, 2021; Kappel, 2018) and (B) PPG (Nellcor, 2021; Nonin Medical, 2021; Tamura et al., 2014; Poh et al., 2010)”
A Survey of Wearable Biometric Recognition Systems
Blasco, J., Chen, T., Tapiador, J., & Lopez, P. P. (2016) · ACM Computing Surveys · doi:10.1145/2968215 · Cited by 145 · see citing works
“A PPG sensor measures blood volume changes within the microvascular bed of the tissue [Tamura et al. 2014].”
Application of Wearable Biosensors to Construction Sites. I: Assessing Workers’ Stress
Jebelli, H., Choi, B., & Lee, S. H. (2019) · Journal of Construction Engineering and Management · doi:10.1061/(asce)co.1943-7862.0001729 · Cited by 146 · see citing works
Liu, J., Yan, B. P., Zhang, Y., Ding, X., Su, P., & Zhao, N. (2018) · IEEE Transactions on Biomedical Engineering · doi:10.1109/tbme.2018.2874957 · Cited by 139 · see citing works
“emitting diode (LED) and photodetector has already been widely adopted by various wearable fitness trackers owing to its low cost, compact size and ease of use [20].”
Hwang, S., Seo, J., Jebelli, H., & Lee, S. H. (2016) · Automation in Construction · doi:10.1016/j.autcon.2016.08.029 · Cited by 139 · see citing works
Monitoring vital signs over multiplexed radio by near-field coherent sensing
Hui, X., & Kan, E. C.-C. (2017) · Nature Electronics · doi:10.1038/s41928-017-0001-0 · Cited by 135 · see citing works
Lee, H., Lee, J., & Shin, M. (2019) · Electronics · doi:10.3390/electronics8020192 · Cited by 131 · see citing works
Algorithms for Monitoring Heart Rate and Respiratory Rate From the Video of a User’s Face
Sanyal, S., & Nundy, K. K. (2018) · IEEE Journal of Translational Engineering in Health and Medicine · doi:10.1109/jtehm.2018.2818687 · Cited by 125 · see citing works
“While there has been some work [12]–[14], [30], [31]–[33] in the optical and near optical frequency ranges, non-contact optical respiratory rate measurement still has potential for”
BackgroundMethodCabanas, A. M., Fuentes-Guajardo, M., Latorre, K., León, D., & Martín-Escudero, P. (2022) · Sensors · doi:10.3390/s22093402 · Cited by 124 · see citing works
“, a greater absorbance for both deoxyhemoglobin and oxyhemoglobin than infrared light [40].”
BackgroundKroll, R. R., Boyd, J. G., & Maslove, D. M. (2016) · Journal of Medical Internet Research · doi:10.2196/jmir.6025 · Cited by 123 · see citing works
“Many newer wearable devices use photoplethysmography (PPG) to record heart rate by measuring differential reflection of light from the skin, based on the pulsatility of superficial blood vessels [14].”
BackgroundWang, G., Atef, M., & Lian, Y. (2018) · IEEE Circuits and Systems Magazine · doi:10.1109/mcas.2018.2849261 · Cited by 121 · see citing works
“However, the signal received from reflectance mode is easily affected by MAs and pressure disturbances, which limit the measurement accuracy [17], [18].”
BackgroundEmerging sensing and modeling technologies for wearable and cuffless blood pressure monitoring
Zhao, L., Liang, C., Huang, Y., Zhou, G., Xiao, Y., Ji, N., Zhang, Y., & Zhao, N. (2023) · npj Digital Medicine · doi:10.1038/s41746-023-00835-6 · Cited by 120 · see citing works
Min, S., An, J., Lee, J. H., Kim, J. H., Joe, D. J., Eom, S. H., Yoo, C. D., Ahn, H., Hwang, J.-Y., Xu, S. H., et al. (2025) · Nature Reviews Cardiology · doi:10.1038/s41569-025-01127-0 · Cited by 132 · see citing works
“…using intrinsic properties such as mechanoelectric 52 (including piezoelectric 53 and triboelectic 54 pulse sensors, piezoresistive sensors 55 , capacitive sensors 56 , field effect transistors 57,58 and electrets 59 ), optoelectronic 60 , ultrasonic 61 and electrophysiological 62 (Tables 1 and 2).”
Anwer, S., Li, H., Antwi‐Afari, M. F., Umer, W., & Wong, A. Y. L. (2021) · Journal of Construction Engineering and Management · doi:10.1061/(asce)co.1943-7862.0002038 · Cited by 119 · see citing works
Mühlen, J. M., Stang, J. S., Skovgaard, E. L., Júdice, P. B., Molina‐García, P., Johnston, W., Sardinha, L. B., Ortega, F. B., Caulfield, B., Bloch, W., et al. (2021) · British Journal of Sports Medicine · doi:10.1136/bjsports-2020-103148 · Cited by 118 · see citing works
Scardulla, F., Cosoli, G., Spinsante, S., Poli, A., Iadarola, G., Pernice, R., Busacca, A., Pasta, S., Scalise, L., & D’Acquisto, L. (2023) · Measurement · doi:10.1016/j.measurement.2023.113150 · Cited by 120 · see citing works
Recent Progress and Challenges of Implantable Biodegradable Biosensors
Alam, F., Ahmed, M. A., Jalal, A. H., Siddiquee, I., Adury, R. Z., Hossain, G. M. M., & Pala, N. (2024) · Micromachines · doi:10.3390/mi15040475 · Cited by 116 · see citing works
“For instance, photo-plethysmography (PPG) sensors, which measure changes in blood volume using light, are used for continuous monitoring of oxygen levels [7].”
MethodIoT Based Remote Health Monitoring System for Patients and Elderly People
Hamim, M., Paul, S., Hoque, S. I., Rahman, M. N., & Baqee, I.-A. (2019) · International Conference on Robotics, Electrical and Signal Processing Techniques (ICREST) · doi:10.1109/icrest.2019.8644514 · Cited by 113 · see citing works
“The changes in blood volume during the transition of phases, systolic to diastolic and vice versa, is exhibited by AC component; the heart rate is responsible for the fundamental frequency of the AC component which is then superimposed onto the DC component [7], [8].”
BackgroundLee, B. G., Choi, B., Jebelli, H., & Lee, S. H. (2021) · Journal of Building Engineering · doi:10.1016/j.jobe.2021.102824 · Cited by 125 · see citing works
Wang, L., Zhou, W., Xing, Y., & Zhou, X. (2018) · Journal of Healthcare Engineering · doi:10.1155/2018/7804243 · Cited by 109 · see citing works
“5mmHg for 85% or more of simultaneous observations [13, 28].”
BackgroundServati, A., Zou, L., Wang, Z. J., Ko, F., & Servati, P. (2017) · Sensors · doi:10.3390/s17071622 · Cited by 110 · see citing works
Wearables in cardiology: Here to stay
Dagher, L., Shi, H., Zhao, Y., & Marrouche, N. F. (2020) · Heart Rhythm · doi:10.1016/j.hrthm.2020.02.023 · Cited by 107 · see citing works
Wearable Sensing of In-Ear Pressure for Heart Rate Monitoring with a Piezoelectric Sensor
Park, J.-H., Jang, D.-G., Park, J., & Youm, S. (2015) · Sensors · doi:10.3390/s150923402 · Cited by 105 · see citing works
“PPG sensors have mainly been applied to fingers, earlobes, or wrists in the form of tweezers- or watch-shaped apparatuses [6].”
MethodA review of IoT systems to enable independence for the elderly and disabled individuals
Pérez, A. J., Siddiqui, F. A., Zeadally, S., & Lane, D. R. (2022) · Internet of Things · doi:10.1016/j.iot.2022.100653 · Cited by 107 · see citing works
Heart rate tracking in photoplethysmography signals affected by motion artifacts: a review
Ismail, S., Akram, U., & Siddiqi, I. (2021) · EURASIP Journal on Advances in Signal Processing · doi:10.1186/s13634-020-00714-2 · Cited by 101 · see citing works
TENG-Boosted Smart Sports with Energy Autonomy and Digital Intelligence
Wang, Y., Gao, Z., Wu, W., Xiong, Y., Luo, J., Sun, Q., Mao, Y., & Wang, Z. L. (2025) · Nano-Micro Letters · doi:10.1007/s40820-025-01778-1 · Cited by 108 · see citing works
“…r e qu e n c y [ 152 ] , po s iti on i ng [ 153 ] , r o t a ti on [ 154 ] , a ng l e , l o a d [ 155 ] , b l ood p r e ss u r e , b l ood oxyg e n [ 156 ] H ea r t r a t e [ 157 ] , b l ood p r e ss u r e , fr e qu e n c y [ 158 ] , a m p lit ud e , acce l e r a ti on [ 159 ] , s w ea t d e t ec…”
Evaluation of biases in remote photoplethysmography methods
Dasari, A., Prakash, S. K. A., Jeni, L. A., & Tucker, C. S. (2021) · npj Digital Medicine · doi:10.1038/s41746-021-00462-z · Cited by 98 · see citing works
Delbeck, S., Vahlsing, T., Leonhardt, S. K., Steiner, G. R., & Heise, H. M. (2018) · Analytical and Bioanalytical Chemistry · doi:10.1007/s00216-018-1395-x · Cited by 95 · see citing works
“The latter originates from several cardiac synchronous vascular factors including changes of blood volume, blood-vessel wall movement, and the variable orientation of red blood cells in vessels [57] mainly assigned to changes in arteries and arterioles, due to the blood pressure changes with each heartbeat.”
BackgroundA stretchable crumpled graphene photodetector with plasmonically enhanced photoresponsivity
Kim, M., Kang, P., Leem, J., & Nam, S. (2017) · Nanoscale · doi:10.1039/c6nr09338h · Cited by 91 · see citing works
A Chair–Based Unobtrusive Cuffless Blood Pressure Monitoring System Based on Pulse Arrival Time
Tang, Z., TAMURA, T., Sekine, M., Huang, M., Chen, W., Yoshida, M., Sakatani, K., Kobayashi, H., & Kanaya, S. (2016) · IEEE Journal of Biomedical and Health Informatics · doi:10.1109/jbhi.2016.2614962 · Cited by 91 · see citing works
“For this reason, the change in reflected green light is greater than that in reflected infrared light when blood pulses through the skin, resulting in a better signal-to-noise ratio for green light source [33].”
BackgroundSignal quality and patient experience with wearable devices for epilepsy management
Nasseri, M., Nurse, E., Glasstetter, M., Böttcher, S., Gregg, N. M., Laks Nandakumar, A., Joseph, B., Pal Attia, T., Viana, P. F., Bruno, E., et al. (2020) · Epilepsia · doi:10.1111/epi.16527 · Cited by 90 · see citing works
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“, infrared, red, and green) to the skin surface and acquiring the light reflection via photodetectors [40].”
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“Heart rate can be measured by PPG-based technologies [79,80], sound-based techniques [81], etc.”
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3D Printing Silicone Elastomer for Patient‐Specific Wearable Pulse Oximeter
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A Review of Skin-Wearable Sensors for Non-Invasive Health Monitoring Applications
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“The most common sites for transmission the are fingertip and earlobe; however, these sites have limited blood perfusion and are susceptible to environmental extremes and daily activities [149].”
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Use of smartphone technology in cardiology
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“In contrast to ECG electrodes, the photoplethysmographic sensors are more patient–friendly since the sensor can be attached to a finger [16], to be integrated into the ear-phones [17], [18], implemented in a forehead band [18], [19] or used as a wrist sensor [18]–[20].”
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“Similarly to contact PPG, iPPG traces variations in the intensity of light reflected by the skin (see (Allen 2007, Tamura et al 2014) for details), but a video camera is used instead of simple photo-detector.”
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BackgroundHuman photoplethysmogram: new insight into chaotic characteristics
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Recent Progress on Organic Near‐Infrared Photodetectors: Mechanism, Devices, and Applications †
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“They are also cheaper and require less maintenance than ECG devices [2].”
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“Ratio of the ac to dc component gives the perfusion index (PI) [12], which”
BackgroundPervasive blood pressure monitoring using Photoplethysmogram (PPG) sensor
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“Figure 2: Principle of the PPG signals (adapted from [20]).”
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“Among different technologies, optical sensors based on photoplethysmography (PPG) have become increasingly popular [9,10] and nowadays have been adopted and integrated in wrist-worn products of several companies.”
BackgroundInfluentialPPG-based Finger-level Gesture Recognition Leveraging Wearables
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“Such applications only focus on examining regular blood flow changing patterns in the radial artery and the ulnar artery, and consider mechanical movement artifacts as noise [18].”
BackgroundHighly stretchable sensors for wearable biomedical applications
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- Authors
- Tamura, T., Maeda, Y., Sekine, M., & Yoshida, M.
- Affiliations
- Osaka Electro-Communication University (JP)
- University of Tsukuba (JP)
- Corresponding author
- Tamura, Toshiyo
- Venue
- Electronics
- Publisher
- MDPI AG
- Published
- 2014-04-23
- Volume
- 3
- Issue
- 2
- Pages
- 282-302
- ISSN
- 2079-9292 (ISSN-L)
- OpenAlex
- W1988681682
- Cited by
- 912
- References
- 75
- Citations by year
- 2026: 67 · 2025: 81 · 2024: 67 · 2023: 76 · 2022: 96 · 2021: 75 · 2020: 86 · 2019: 101 · 2018: 88 · 2017: 77 · 2016: 59 · 2015: 33 · 2014: 6
- FWCI
- 30.29
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Electronics (publishedVersion, cc-by)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
- Physical Sciences › Engineering › Biomedical Engineering › Advanced Sensor and Energy Harvesting Materials
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Rate Variability and Autonomic Control
- Keywords
- photoplethysmography, wearable sensors, pulse rate monitoring, green light-emitting diodes, photodetectors
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