Filtering Analysis Based on Improved Wavelet Threshold Function
Xiaoyan Zhao · Noise and Vibration Control · 2013
Wavelet analysis,as one of the advanced time-frequency analysis methods,has been widely used in signal and figure processing,damage detection and so on.Many threshold functions have been proposed based on wavelet transformation in noise processing,but their filtering efficiencies are quite different.In this paper,based on binary wavelet transformation and Sigmoid function,a new threshold function between soft and hard threshold functions was built.By adjusting different parameters of this function,the soft or hard threshold functions could asymptotically approached.According to the results of filtering of six different signals using different thresholds,it can be concluded that the new threshold function can raise the signal-to-noise ratio,and make the filtered signal closer to the true signal.