The use of wavelet packets to improve the detection of cardiac sounds from the fetal phonocardiogram

Jiménez, Alfredo; Ortiz, Mario R; Peña, Marcela; Charleston, S.; Aljama, A.T.; Gonzalez, Rosa Maria

doi:10.1109/cic.1999.826008

Cited by 14 publications

(8 citation statements)

References 4 publications

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“…The data of maximal value on the smoothed signal can be, therefore, right-or left-shifted from the real peak of the sound, causing certain dispersion and variability manifested as random noise. It is possible that improving the quality of the acoustic signal and the application of other more robust processing techniques could decrease the technical errors [27].…”

Section: Discussionmentioning

confidence: 99%

Differences in foetal heart rate variability from phonocardiography and abdominal electrocardiography

Ortiz

Gonzalez

Peña

et al. 2002

Journal of Medical Engineering & Technology

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The agreement of the phonocardiographic method to provide foetal heart rate variability (FHRV) indices equivalent to those derived from abdominal electrocardiography was tested. 15 pregnant women were recruited in order to obtain antepartum foetal phonocardiograms and abdominal electrocardiograms three minutes long. From the respective sound (SS) and electric (RR) time series, typical temporal and spectral indices of FHRV were computed and compared. Means of the SS and RR intervals were not significant (P> 0.05) and these showed a correlation r=0.98. However, the temporal indices, P(TOT), HF and LF/HF presented differences (P< 0.05), since SS values were higher. Spectral coherence decreased below 0.5 for frequencies above 0.28+ 0.07 Hz, where bands resembling maternal and foetal breathing movements were noted. Particularly above 0.28Hz, temporal and spectral FHRV indices derived from phonocardiography and electrocardiography show differences. Quality of the signal, processing techniques, and maternal and foetal respiratory factors could account to explain these.

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Section: Discussionmentioning

confidence: 99%

Differences in foetal heart rate variability from phonocardiography and abdominal electrocardiography

Ortiz

Gonzalez

Peña

et al. 2002

Journal of Medical Engineering & Technology

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“…An additive white Gaussian noise with zero mean [5] and limited duration impulses (LDI) that saturate the !peG signal and simulate different kinds of acoustic bursts due to maternal fast body movements, maternal coughing, acoustic sensor displacements and generic high magnitude external noises. LDI were simulated by generating random spikes along the whole length of simulated !peG signals.…”

Section: B Jpeg Simulationmentioning

confidence: 99%

“…The result is an attenuation of the signals and the fetal heart sound becomes too weak causing a poor SNR [4,5].…”

Section: Introductionmentioning

confidence: 99%

A simulating software of fetal phonocardiographic signals

Ruffo

Cesarelli

Romano

et al. 2010

Proceedings of the 10th IEEE International Conference on Information Technology and Applications in Biomedicine

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A valuable alternative to traditional diagnostic tool to record fetal heart rate, to monitor the general fetal wellbeing, is fetal phonocardiography, a passive and low cost acoustic recording of fetal heart sounds. In this paper, it is presented a simulating software of fetal phonocardiographic signals relative to different fetal physiological states and recording conditions (for example different kinds and levels of noise). This software can be useful to test and assess fetal heart rate extraction algorithms from fetal phonocardiographic recordings and as a teaching tool for demonstration to medical students and others

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“…Indeed, FHS and FBM have been long researched giving rise to methods with different types of sensors [3,6,10,26,31], number of channels [17,28], and signal processing schemes [1,[14][15][16]. However, even though high quality technology and powerful processing schemes have been combined, there is no such foetal device yet available.…”

Section: Introductionmentioning

confidence: 98%

“…Furthermore, because of the interest in specific foetal information, there might be some extra and valuable foetal/ maternal information that is irreversibly discarded such as maternal heart and respiratory rates. Some studies have shown some improvement in the SNR of the signals [6,14,28], but the detection of FHS and FBM may still be difficult, and it is clear that the solution requires not only sophisticated signal processing methods but also a complete different signal processing perspective for the abdominal phonogram. This signal processing perspective, instead of searching for a pre-selected component, should take advantage of the abundance of information in the abdominal phonogram and separate all its components out.…”

Section: Introductionmentioning

confidence: 98%

Extracting sources from noisy abdominal phonograms: a single-channel blind source separation method

Jiménez-González

James

2009

Med Biol Eng Comput

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In this work we highlight a methodology that extracts sources from noisy single-channel abdominal phonograms. First, an appropriate matrix of delays is constructed. Next, multiple independent components are calculated using the FastICA algorithm. Then these components are projected back to the measurement space and classified for recovering the sources of interest. Single-channel phonograms obtained from three different subjects were analysed. Results show successful extraction of foetal heart sounds (FHS), maternal respiration/pulse wave, and line noise. It is important to point out the high performance of the method for extracting the former two as separate sources; especially due to the fact that pulse wave and FHS may overlap as maternal and foetal QRSs do in the abdominal ECG. The most outstanding factor is that this is achieved using a single-channel method. So, this approach extracts physiological sources from noisy abdominal phonograms, and we believe it will be useful for surveillance, not only for foetal well-being but also for maternal condition.

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The use of wavelet packets to improve the detection of cardiac sounds from the fetal phonocardiogram

Cited by 14 publications

References 4 publications

Differences in foetal heart rate variability from phonocardiography and abdominal electrocardiography

Differences in foetal heart rate variability from phonocardiography and abdominal electrocardiography

A simulating software of fetal phonocardiographic signals

Extracting sources from noisy abdominal phonograms: a single-channel blind source separation method

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