比较了软阈值，硬阈值及当今各种阈值计算方法,ML法能够很好的估计信号的信噪比,最终的权值矩阵就是滤波器的系数。- Comparison of soft threshold and hard threshold and today various threshold calculation method, ML estimation method can be a good signal to noise ratio, The final weight matrix is ??the filter