【摘要】 针对传统小波阈值函数在阈值处的不连续性、小波估计系数存在偏差等不足,导致去噪后的图像出现失真、产生吉布斯震荡等问题,提出了一种改进的阈值函数,与常用的硬阈值、软阈值以及已有改进的阈值函数相比,该函数不仅易于计算,而且具有优越的数学特性。为了验证该阈值函数的优越性,通过仿真实验对几种小波去噪方法的峰值信噪比(PSNR)与均方差(MSE)进行了对比。实验结果表明,此去噪方法无论是在视觉效果上,还是在均方差和信噪比性能分析上均优于常用的阈值函数。更多还原

【Abstract】 Since the traditional wavelet threshold functions have some drawbacks such as the non-continuity on the points of threshold,and large deviation of estimated wavelet coefficient,distortion and Gibbs phenomenon occur after denoising.To overcome these drawbacks,an improved threshold function was proposed.Compared with the hard,soft threshold functions and the existing improved threshold function,the proposed function not only is easy to be calculated,but also has the superior mathematical characteristics.To verify its advantages,a series of simulation experiments were performed,the Peak Signal-toNoise Ratio(PSNR) and Mean Squared Error(MSE) values were compared with other different denoising methods.The experimental results indicate that it is better than above mentioned denoising methods in both the visual effects and the performance of PSNR and MSE.更多还原