The Application of an Improved Wavelet Threshold Function in De-noising of Heart Sound Signal

Heart sound can reflect the pathological characteristics of cardiovascular system. De-noising of heart sound is the basis of accurate identifying information. Wavelet transform is often used to de-noise heart sound signals. In this paper, by analyzing the advantages and disadvantages of traditional wavelet threshold and two improved threshold functions, a new two parameter adjustable wavelet threshold function is proposed. This function has a transition region which is more consistent with the continuous characteristics of the signal, and improves the signal integrity after de-noising. The experimental results show that the improved new function is better than the traditional wavelet threshold de-noising method in SNR and RMSE of heart sound signal, which has a certain practical value.