基于二进小波变换和软阈值改进的信号消噪

软阈值消噪是信号消噪中的标准算法.理论上,软阈值方法在最小最大误差方面是近 似最优的.研究表明,通过结合系数消噪和软阈值方法,可以达到更低的误差下界.由于离散小 波是非平移不变的,因而重构过程中会出现人工噪声.为了避免这个问题,采用了具有平移不变 性的二进小波变换.实验结果表明,文中所提算法的消噪结果具有更高的信噪比和更光滑的外观.

Signal De-Noising by Improving Soft Thresholding on the Dyadic Wavelet Transform

Soft thresholding method has been a standard procedure in signal de-noising. Theoretically, it is also almost optimal in the sense of minimax mean-squared error. This paper shows that by combining coefficient de-noising and soft thresholding, a lower bound of mean-squared-error can be achieved. Furthermore, the translation-invariant (TI) dyadic wavelet transform is used instead of DWT, which can avoid the artifacts caused by the non-TI reconstruction. Experiments show that the proposed method improves the signal-to-noise ratios of the de-noised signals. Moreover, the de-noised signals have smooth and nice visual appearance.