A Method of Improved Wavelet Threshold for Signal De-Noising

This paper presents an improved threshold function in order to improve the effect of electro-cardio signal denoising. This improved threshold function is continuous; the wavelet coefficients are reduced to zero smoothly according to the function when their absolute values are less than threshold value. Adding a factor to the function can change the form of threshold function and adjust the estimated deviation of wavelet coefficients. The results of MATLAB simulation show that the denoising effect of this method is better than soft and hard threshold. It may help to improve the quality of diagnosis if this method is applied to electro-cardio signal pre-processing and it can be applied in communication systems for speech signal denoising.