Method and device for determining fetal heart sounds by passive sensing and system for examining fetal heart function

Abstract

In the method according to the invention a phonocardiographic signal, obtained by a passive acoustic sensor (10) from a maternal abdominal wall, is pre-filtered, amplified, digitized, digitally filtered by means of a programmable amplifier and filter unit (20), is stored in an intermediate memory and autocorrelation is performed by means of an autocorrelation unit (30) in a time window of a predetermined size. The signals obtained as a result of autocorrelation are fed to an input of a fuzzy expert system (40), wherein local maximums of the signals, temporal location of the local maximums and variation of the temporal location of the local maximums are determined by the fuzzy expert system (40), and, applying those as input parameters or signals of the fuzzy expert system, those are classified into probability groups utilizing a fuzzy rule set of a decision logic stored in a knowledge base and biologically expected data and are evaluated.

Description

technical field [0001] The present invention relates to a method for determining fetal heart sounds by passive sensing and a device for implementing the method, preferably the device can be used in a home environment and preferably , the device can also be applied to telemedicine. The invention also relates to a system for examining fetal heart function. Background technique [0002] It is known that clearly interpretable measurements of fetal cardiac function can only be obtained with tests of longer duration (approximately 20 minutes); A phenomenon associated with a possible symptom of a disease. [0003] The type of measurement most commonly used today is the ultrasound method based on the Doppler principle, which is an active method and thus involves continuous energy irradiation over a non-negligible period of time and does not Suitable for unsupervised testing at home. The choice of passive methods suitable for examining fetal cardiac function is very limited, prim...

AI Technical Summary

Problems solved by technology

[0006] According to known schemes, the aim is to filter out the signal generated by the periodic heartbeat from the detected noise-laden signal by means of autocorrelation, which results in a lower amplitude aperiodic signal (essentially noise ) decreases but does not increase sensitivity and accuracy

In many schemes, mathematical methods of error correction are applied to filter the sound produced by the heartbeat from the noisy signal, but even these methods do not improve the effective sensitivity and accuracy

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