基于阈值的小波域非线性滤波的核心步骤是阈值的选取 .硬阈值t=cσ被证明是很有效的 ,但一般来说最佳的参数c会随信号的不同和迭加噪声的强度而变化 .本文构造了一个信号MSE(均方差 )函数的近似函数 ,以此做为阈值参数c选取的一种依据 .通过计算不同c下该函数的值 ,来判断使该函数最小的阈值参数c.仿真结果表明了真实MSE函数与本文提出的近似函数的一致性 ,据此选取c是可信的 The key step in the threshold-based nonlinear filtering of wavelet domain is the selection of the threshold.The hard threshold t = cσ proved to be very effective, but in general the best parameter c will vary with different signals and intensity of superimposed noise In this paper, an approximate function of signal MSE (Mean Square Error) function is constructed, which is used as a basis for selecting threshold parameter C. By calculating the value of this function under different c, the threshold parameter c that minimizes the function is determined. The simulation results show the consistency between the real MSE function and the approximate function proposed in this paper, so c is credible