The application of an improved wavelet threshold denoising method in heart sound signal

To reduce the noise in the heart sound signal, an improved wavelet threshold denoising method is proposed in this paper. The method is based on wavelet threshold denoising method proposed by Donoho. The auther analyzes advantages and disadvantages of two traditional threshold function, and propose a new method in order to improve their disadvantages. The new method not only improve the discontinuity of hard wavelet threshold denoising method but also reduce constant bias of soft wavelet threshold denoising method. The simulation shows that the SNR and MSE of the heart sound signal denoised by the improved method is superior to by the hard and soft wavelet threshold denoising method.