Wavelet-based denoising method for real phonocardiography signal recorded by mobile devices in noisy environment

Gradolewski, Dawid; Redlarski, Grzegorz

doi:10.1016/j.compbiomed.2014.06.011

Cited by 81 publications

(54 citation statements)

References 27 publications

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“…The most widely used noise reduction methods of HS are wavelet denoising algorithms which are based on DWT [ 39 , 40 , 51 – 58 ]. The general wavelet denoising procedure is as follows: Decomposition Apply DWT to the noisy signal to produce the multi-level wavelet coefficients.…”

Section: Literature Articles Review Resultsmentioning

confidence: 99%

“…One assumption made in [ 39 ] is that the environmental noise can be modeled as white Gaussian noise. However, according to the authors of [ 51 ], some color noises can also be found in the real HS signals collected by using their self-produced HS recording device. More specifically, based on the study of signal spectrum, the power spectral densities (PSD) of the noise registered during real HS signal measurements is very similar to the PSD of red or pink noise.…”

Section: Literature Articles Review Resultsmentioning

confidence: 99%

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The electronic stethoscope

et al. 2015

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Most heart diseases are associated with and reflected by the sounds that the heart produces. Heart auscultation, defined as listening to the heart sound, has been a very important method for the early diagnosis of cardiac dysfunction. Traditional auscultation requires substantial clinical experience and good listening skills. The emergence of the electronic stethoscope has paved the way for a new field of computer-aided auscultation. This article provides an in-depth study of (1) the electronic stethoscope technology, and (2) the methodology for diagnosis of cardiac disorders based on computer-aided auscultation. The paper is based on a comprehensive review of (1) literature articles, (2) market (state-of-the-art) products, and (3) smartphone stethoscope apps. It covers in depth every key component of the computer-aided system with electronic stethoscope, from sensor design, front-end circuitry, denoising algorithm, heart sound segmentation, to the final machine learning techniques. Our intent is to provide an informative and illustrative presentation of the electronic stethoscope, which is valuable and beneficial to academics, researchers and engineers in the technical field, as well as to medical professionals to facilitate its use clinically. The paper provides the technological and medical basis for the development and commercialization of a real-time integrated heart sound detection, acquisition and quantification system.

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Section: Literature Articles Review Resultsmentioning

confidence: 99%

Section: Literature Articles Review Resultsmentioning

confidence: 99%

The electronic stethoscope

et al. 2015

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“…The CM software interface allows real-time observation of the cervical ultrasound signal as well as applied pressure. The ultrasound peak position for cervix internal os signal was calculated with the use of a signal envelope after the Gaussian complex wavelet filtering [29] at 3 MHz frequency. The cervical elasticity was calculated as a ratio of the applied load (stress) to the surface of the cervix from the CM probe to the resultant changes of the cervical length (strain).…”

Section: Cervix Monitor (Cm)mentioning

confidence: 99%

Cervical Characterization with Tactile-Ultrasound Probe

Egorov¹,

Rosen

Raalte³

et al. 2020

OJOG

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Background: Premature cervical softening and shortening may be considered an early mechanical failure that predisposes to preterm birth. Preliminary clinical studies demonstrate that cervical elastography may be able to quantify this phenomenon and predict spontaneous preterm delivery. Objective: To explore a new approach for cervix elasticity and length measurements with tactile-ultrasound probe. Methods: Cervix probe has tactile array and ultrasound transducer designed to apply controllable load to cervix and acquire stress-strain data for calculation of cervical elasticity (Young's modulus) and cervical length for four cervix sectors. Average values, standard deviations, intraclass correlation coefficients and the 95% limits of agreement (Bland-Altman plots) were estimated. Results: Ten non-pregnant and ten pregnant women were examined with the probe. The study with non-pregnant women demonstrated a reliable acquisition of the tactile signals. The ultrasound signals had a prolonged appearance; identification of the internal os of the cervix in these signals was not reliable. The study with pregnant women with the gestational age of 25.4 ± 2.3 weeks demonstrated reliable data acquisition with real-time visualization of the ultrasound signals. Average values for cervical elasticity and standard deviations of 19.7 ± 15.4 kPa and length of 30.7 ± 6.6 mm were calculated based on two measurements per 4 sectors. Measurement repeatability calculated as intraclass correlation coefficients between two measurements at the same cervix sector on pregnant women was found to be 0.97 for cervical elasticity and 0.93 for the cervical length. The 95% limits of agreement of 1) cervical elasticity were from −22.4% to +14.9%, and 2) cervical length from −13.3% to +16.5%. Conclusions: This study demonstrated clinically acceptable measurement performance and reproducibility. The availability of stress-strain data allowed the computation of cervical elasticity and length. This approach has the potential to provide cervical markers to predict spontaneous preterm delivery.

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“…The underlying heart disorders and its nonlinearities can be observed by wavelet packet transform [24]. Wavelet denoising algorithms also provide the possibility of immediate processing of recorded PCG Signal [25] [26]. Various studies show that uncertainties in heart sounds can also be handled by fuzzy logic algorithms [27].…”

Section: Related Workmentioning

confidence: 99%

Doppler Ultrasound Based Non-Invasive Heart Rate Telemonitoring System for Wellbeing Assessment

Queyam¹,

Pahuja²,

Singh³

2018

IJISA

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Telemonitoring in the field of healthcare has vastly improved the quality of clinical diagnosis and disease prevention by providing timely medical consultation to people living in rural and remote areas. To monitor the health state of a patient certain vital physiological parameter like electrocardiogram (ECG), respiration rate, blood pressure, oxygen saturation, etc. are acquired and analyzed. Listening to the heart sounds (auscultation) is also a quick method to monitor the health state of the patient's heart. In this paper, we propose the use of a portable Doppler ultrasound sensor for measuring the heart sounds reliably and to transmit the data for further clinical telemonitoring. We have developed an ultrasound-based hardware prototype which is non-invasive in nature and easy to operate. Its portability, high accuracy, low cost, and wireless nature make this device suitable for home-based self-diagnostic applications. The developed prototype was successfully able to capture both fundamental heart sounds S 1 and S 2 reliably and transfer the signal wirelessly to the LabVIEW-based monitoring and data logging unit. This unit extracts clinically useful health information like heart rate (HR), R-R interval and heart rate variability (HRV) using signal processing algorithms. Health information is then transmitted via the Internet to a distant hospital for further improved clinical diagnosis and consultancy. The prototype was validated on 40 healthy males in the age group of 25-35 years, and the results show an overall accuracy of 96.74% in HR detection when compared with an ECG sensor, a photoplethysmograph (PPG) sensor, a pulse oximeter device and manual auscultation.

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Wavelet-based denoising method for real phonocardiography signal recorded by mobile devices in noisy environment

Cited by 81 publications

References 27 publications

The electronic stethoscope

The electronic stethoscope

Cervical Characterization with Tactile-Ultrasound Probe

Doppler Ultrasound Based Non-Invasive Heart Rate Telemonitoring System for Wellbeing Assessment

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