Method for eliminating friction noise of electronic stethoscope

Abstract

The invention discloses a method for eliminating friction noise of an electronic stethoscope. The method comprises the following step: S1 dividing an acquired mixed signal into n0 window signals for the first time, finding out the amplitude of each window signal, taking the absolute value, enabling the maximum value to be A_max, and recording the position i, j, wherein i is the mark number of thewindow, i=0, 1, 2..., j is the position corresponding to waveform data of the window, and j=0, 1, 2.... According to the method, the friction noise generated between an auscultation head and the garment is eliminated based on the period average energy proportion algorithm, the friction noise generated between the auscultation head and a garment can be eliminated, and thus heart sound signals without friction noise are obtained; and while the friction noise signals are eliminated, the integrity of the heart sound signals is guaranteed.

Description

technical field [0001] The invention relates to the technical field of medical devices, in particular to a method for eliminating friction sound of an electronic stethoscope. Background technique [0002] With the progress of the times, people pay more and more attention to health, and various medical device technologies have developed rapidly. As far as the stethoscopes that we are more likely to see every day are concerned, there are also many types, which are mainly divided into two categories: traditional stethoscopes and electronic stethoscopes. Compared with traditional stethoscopes, electronic stethoscopes generally have popular functions such as recording and playback; in addition, the essential difference between advanced electronic stethoscopes and traditional stethoscopes is that the former can actively reduce noise, while the latter can only passively Noise reduction. [0003] The doctor can obtain the patient's physiological information by listening to the pat...

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Problems solved by technology

[0007] However, in reality, the friction sound signal generated between the auscultation head and clothes has the characteristics of non-periodic, short-term, and non-continuous, and the friction noise not only appears in the first heart sound interval, but also in other heart sound intervals, so It is not suitable to directly apply the above method to remove the friction noise generated between the auscultation head and clothes, specifically: (1) because the peak value of the friction sound amplitude generated between the auscultation head and YYY material clothes is often higher than the peak value of the heart sound signal amplitude It should be small, even if there is a period of friction noise acting on a certain period of the heart sound signal and completely covering all periods of the second, third and fourth heart sound signals or even the entire heart sound signal, it is difficult for MAA>=3*MMAA to exist, that is, the above The method will mistakenly believe that there is no friction noise in the heart sound, but the friction noise does exist and seriously affects the doctor's hearing of the patient's heart sound; The first direction change point later, however, only eliminates the noise in the peak corresponding to the maximum peak value of the window, and also deletes the heart sound signal at this position, but it is powerless to the noise outside the peak, and it also causes Incompleteness of the heart sound signal

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