Search for: photoplethysmography--ppg
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    Low complexity heart rate measurement from wearable wrist-type photoplethysmographic sensors robust to motion artifacts

    , Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, 15 April 2018 through 20 April 2018 ; Volume 2018-April , 2018 , Pages 921-924 ; 15206149 (ISSN) ; 9781538646588 (ISBN) Boloursaz Mashhadi, M ; Farhadi, M ; Essalat, M ; Marvasti, F ; Sharif University of Technology
    This paper presents a low complexity while accurate Heart Rate (HR) estimation technique from signals captured by Photoplethysmographic (PPG) sensors worn on the wrist during intensive physical exercise. Wrist-type PPG signals experience severe Motion Artifacts (MA) that hinder efficient HR estimation especially during intensive physical exercises. To suppress the motion artifacts efficiently, simultaneous 3 dimensional acceleration signals are used as reference MAs. The proposed method achieves an Average Absolute Error (AAE) of 1.19 Beats Per Minute (BPM) on the 12 benchmark PPG recordings in which subjects run at speeds of up to 15 km/h. This method also achieves an AAE of 2.17 BPM on the... 

    Sensor module for multi-channel wireless photoplethysmography system

    , Article 2007 5th Student Conference on Research and Development, SCORED, Selangor, 11 December 2007 through 12 December 2007 ; 2007 ; 1424414709 (ISBN); 9781424414703 (ISBN) Kadhim, A. Y ; Mohd Ali, M. A ; Zahedi, E ; Sharif University of Technology
    The digital sensor module is developed to sample the input signal fed from a photo-sensor probe at sampling times ranging from 400-4000 μs equivalent to sampling rates of 2500-250 sample/second (S/s), respectively. The module produces 16-bit data packets which are transmitted serially and plotted to output the photoplethysmography signal (PPG). It displays accurate sampling values (packets) similar to the calculated ones. ©2007 IEEE  

    An age index for vascular system based on photoplethysmogram pulse contour analysis

    , Article IFMBE Proceedings ; Volume 21 IFMBE, Issue 1 , 2008 , Pages 125-128 ; 16800737 (ISSN); 9783540691389 (ISBN) Chellappan, K ; Mohd Ali, M. A ; Zahedi, E ; Sharif University of Technology
    Springer Verlag  2008
    An approach based pulse on contour analysis is proposed for the development of an aging index for the vascular system. The approach is non-invasive, using photoplethysmography (PPG), which is in wide clinical use. A probe is applied to the subject's finger-tip to provide a measure of the pulse waveform. The measured waveforms are filtered, digitized and post-processed. Individual pulses are extracted and the best pulse was selected by using the best pulse selection algorithm. Pulse contour analysis is then performed with specially formulated PPG fitness equation. Results of measurements taken from 72 subjects are reported. The age range of the subjects was from 19 to 68 years, all of them... 

    Modeling of photoplethysmography signal for quantitative analysis of endothelial cells during reactive hyperemia

    , Article 2012 19th Iranian Conference of Biomedical Engineering, ICBME 2012 ; 2012 , Pages 174-178 ; 9781467331302 (ISBN) Shiri, F ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
    In this study, at first the cardiovascular system is modeled based on the 1D method and then the simulation of the reactive hyperemia experiment has been applied on the model. In this simulation, by applying a cuff at the brachial artery, the flow downstream of the cuff is occluded. Then with releasing the cuff immediately, a large amount of shear stress, about 4 times the basal amount, is applied downstream of the cuff and consequently to the endothelial cells in a very short moment. Considering a reported experimental transfer function between shear stress and vasodilation, the increase of the artery diameter due to the sudden increase of the shear stress is obtained. Finally, the... 

    Cuff-less high-accuracy calibration-free blood pressure estimation using pulse transit time

    , Article Proceedings - IEEE International Symposium on Circuits and Systems, 24 May 2015 through 27 May 2015 ; Volume 2015-July , 2015 , Pages 1006-1009 ; 02714310 (ISSN) ; 9781479983919 (ISBN) Kachuee, M ; Kiani, M.M ; Mohammadzade, H ; Shabany, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Recently a few methods have been proposed in the literature for non-invasive cuff-less estimation of systolic and diastolic blood pressures. One of the most prominent methods is to use the Pulse Transit Time (PTT). Although it is proven that PTT has a strong correlation with the systolic and diastolic blood pressures, this relation is highly dependent to each individuals physiological properties. Therefore, it requires per person calibration for accurate and reliable blood pressure estimation from PTT, which is a big drawback. To alleviate this issue, in this paper, a novel method is proposed for accurate and reliable estimation of blood pressure that is calibration-free. This goal is... 

    Non-invasive techniques for assessing the endothelial dysfunction: ultrasound versus photoplethysmography

    , Article IFMBE Proceedings, 3 December 2008 through 6 December 2008 ; Volume 23 , 2009 , Pages 65-68 ; 16800737 (ISSN) ; 9783540928409 (ISBN) Zaheditochai, M ; Jaafar, R ; Zahedi, E ; Sharif University of Technology
    Endothelial dysfunction, which can be noninvasively assessed by flow mediated vasodilation (FMD), predicts an increased rate of adverse cardiovascular events. The endothelial dysfunction is considered as a leading cause of development and progression of the atherosclerotic process. The main aim of this study is to review different non-invasive methods to assess the endothelial dysfunction and to propose enhancements to a new method based on photoplethysmography (PPG). First, non-invasive techniques developed for the evaluation of peripheral endothelial function (including the Doppler ultrasound (US)) will be reviewed. Although noninvasive, US -based techniques present a few disadvantages. To... 

    A brief comparison of adaptive noise cancellation, wavelet and cycle-by-cycle fourier series analysis for reduction of motional artifacts from PPG signals

    , Article IFMBE Proceedings, 30 April 2010 through 2 May 2010 ; Volume 32 IFMBE , April , 2010 , Pages 243-246 ; 16800737 (ISSN) ; 9783642149979 (ISBN) Malekmohammadi, M ; Moein, A ; Sharif University of Technology
    The accuracy of Photoplethysmographic signals is often not adequate due to motional artifacts induced in the recording site. Over recent decades there has been a widespread effort to reduce these artifacts and different methods are used for this aim. Nevertheless there are still some contradictory results reported by different methods about their effectiveness in artifact reduction. In this paper, we aim to compare three of established methods for PPG noise reduction on a unique dataset. Among different reported methods, we have chosen Adaptive Noise Cancellation (ANC), Discrete Wavelet Transform (DWT) and a newly developed method Cycle-by-cycle Fourier Series Analysis (CFSA) for denoising.... 

    A low-power signal-dependent sampling technique: analysis, implementation, and applications

    , Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 67, Issue 12 , 2020 , Pages 4334-4347 Hadizadeh Hafshejani, E ; Elmi, M ; Taherinejad, N ; Fotowat Ahmady, A ; Mirabbasi, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Sensors are among essential building blocks of any Cyber-Physical Systems (CPSs). Acquisition and processing of their sensory data contribute to the power consumption and computation load of the overall CPSs. For data acquisition, the conventional fixed frequency sampling in many such systems is sub-optimal since a sizable number of samples do not contain important information. In this work, we propose a Signal-Dependent Sampling (SDS) method and present its associated circuit implementation. Using the proposed SDS method, the number of retained samples is significantly reduced with little or negligible compromise in the quality of the (reconstructed) signal. The associated error and added...